On Mon, Jul 6, 2015 at 6:08 PM, Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> wrote: > A System Trace Module (STM) is a device exporting data in System Trace > Protocol (STP) format as defined by MIPI STP standards. Examples of such > devices are Intel Trace Hub and Coresight STM. > > This abstraction provides a unified interface for software trace sources > to send their data over an STM device to a debug host. In order to do > that, such a trace source needs to be assigned a pair of master/channel > identifiers that all the data from this source will be tagged with. The > STP decoder on the debug host side will use these master/channel tags to > distinguish different trace streams from one another inside one STP > stream. > > This abstraction provides a configfs-based policy management mechanism > for dynamic allocation of these master/channel pairs based on trace > source-supplied string identifier. It has the flexibility of being > defined at runtime and at the same time (provided that the policy > definition is aligned with the decoding end) consistency. > > For userspace trace sources, this abstraction provides write()-based and > mmap()-based (if the underlying stm device allows this) output mechanism. > > For kernel-side trace sources, we provide "stm_source" device class that > can be connected to an stm device at run time. > > Cc: linux-api@xxxxxxxxxxxxxxx > Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> > Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> > --- > Documentation/ABI/testing/configfs-stp-policy | 48 + > Documentation/ABI/testing/sysfs-class-stm | 14 + > Documentation/ABI/testing/sysfs-class-stm_source | 11 + > Documentation/ioctl/ioctl-number.txt | 3 + > Documentation/trace/stm.txt | 80 ++ > drivers/Kconfig | 2 + > drivers/Makefile | 1 + > drivers/hwtracing/stm/Kconfig | 8 + > drivers/hwtracing/stm/Makefile | 3 + > drivers/hwtracing/stm/core.c | 1029 ++++++++++++++++++++++ > drivers/hwtracing/stm/policy.c | 529 +++++++++++ > drivers/hwtracing/stm/stm.h | 87 ++ > include/linux/stm.h | 126 +++ > include/uapi/linux/stm.h | 50 ++ > 14 files changed, 1991 insertions(+) > create mode 100644 Documentation/ABI/testing/configfs-stp-policy > create mode 100644 Documentation/ABI/testing/sysfs-class-stm > create mode 100644 Documentation/ABI/testing/sysfs-class-stm_source > create mode 100644 Documentation/trace/stm.txt > create mode 100644 drivers/hwtracing/stm/Kconfig > create mode 100644 drivers/hwtracing/stm/Makefile > create mode 100644 drivers/hwtracing/stm/core.c > create mode 100644 drivers/hwtracing/stm/policy.c > create mode 100644 drivers/hwtracing/stm/stm.h > create mode 100644 include/linux/stm.h > create mode 100644 include/uapi/linux/stm.h > > diff --git a/Documentation/ABI/testing/configfs-stp-policy b/Documentation/ABI/testing/configfs-stp-policy > new file mode 100644 > index 0000000000..421ce6825c > --- /dev/null > +++ b/Documentation/ABI/testing/configfs-stp-policy > @@ -0,0 +1,48 @@ > +What: /config/stp-policy > +Date: June 2015 > +KernelVersion: 4.3 > +Description: > + This group contains policies mandating Master/Channel allocation > + for software sources wishing to send trace data over an STM > + device. > + > +What: /config/stp-policy/<device>.<policy> > +Date: June 2015 > +KernelVersion: 4.3 > +Description: > + This group is the root of a policy; its name is a concatenation > + of an stm device name to which this policy applies and an > + arbitrary string. If <device> part doesn't match an existing > + stm device, mkdir will fail with ENODEV; if that device already > + has a policy assigned to it, mkdir will fail with EBUSY. > + > +What: /config/stp-policy/<device>.<policy>/device > +Date: June 2015 > +KernelVersion: 4.3 > +Description: > + STM device to which this policy applies, read only. Same as the > + <device> component of its parent directory. > + > +What: /config/stp-policy/<device>.<policy>/<node> > +Date: June 2015 > +KernelVersion: 4.3 > +Description: > + Policy node is a string identifier that software clients will > + use to request a master/channel to be allocated and assigned to > + them. > + > +What: /config/stp-policy/<device>.<policy>/<node>/masters > +Date: June 2015 > +KernelVersion: 4.3 > +Description: > + Range of masters from which to allocate for users of this node. > + Write two numbers: the first master and the last master number. > + > +What: /config/stp-policy/<device>.<policy>/<node>/channels > +Date: June 2015 > +KernelVersion: 4.3 > +Description: > + Range of channels from which to allocate for users of this node. > + Write two numbers: the first channel and the last channel > + number. > + > diff --git a/Documentation/ABI/testing/sysfs-class-stm b/Documentation/ABI/testing/sysfs-class-stm > new file mode 100644 > index 0000000000..c9aa4f3fc9 > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-class-stm > @@ -0,0 +1,14 @@ > +What: /sys/class/stm/<stm>/masters > +Date: June 2015 > +KernelVersion: 4.3 > +Contact: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> > +Description: > + Shows first and last available to software master numbers on > + this STM device. > + > +What: /sys/class/stm/<stm>/channels > +Date: June 2015 > +KernelVersion: 4.3 > +Contact: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> > +Description: > + Shows the number of channels per master on this STM device. > diff --git a/Documentation/ABI/testing/sysfs-class-stm_source b/Documentation/ABI/testing/sysfs-class-stm_source > new file mode 100644 > index 0000000000..57b8dd39bb > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-class-stm_source > @@ -0,0 +1,11 @@ > +What: /sys/class/stm_source/<stm_source>/stm_source_link > +Date: June 2015 > +KernelVersion: 4.3 > +Contact: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> > +Description: > + stm_source device linkage to stm device, where its tracing data > + is directed. Reads return an existing connection or "<none>" if > + this stm_source is not connected to any stm device yet. > + Write an existing (registered) stm device's name here to > + connect that device. If a device is already connected to this > + stm_source, it will first be disconnected. > diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt > index 611c52267d..7fa29b4ece 100644 > --- a/Documentation/ioctl/ioctl-number.txt > +++ b/Documentation/ioctl/ioctl-number.txt > @@ -81,6 +81,9 @@ Code Seq#(hex) Include File Comments > 0x22 all scsi/sg.h > '#' 00-3F IEEE 1394 Subsystem Block for the entire subsystem > '$' 00-0F linux/perf_counter.h, linux/perf_event.h > +'%' 00-0F include/uapi/linux/stm.h > + System Trace Module subsystem > + <mailto:alexander.shishkin@xxxxxxxxxxxxxxx> > '&' 00-07 drivers/firewire/nosy-user.h > '1' 00-1F <linux/timepps.h> PPS kit from Ulrich Windl > <ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/> > diff --git a/Documentation/trace/stm.txt b/Documentation/trace/stm.txt > new file mode 100644 > index 0000000000..e140f2e8d7 > --- /dev/null > +++ b/Documentation/trace/stm.txt > @@ -0,0 +1,80 @@ > +System Trace Module > +=================== > + > +System Trace Module (STM) is a device described in MIPI STP specs as > +STP trace stream generator. STP (System Trace Protocol) is a trace > +protocol multiplexing data from multiple trace sources, each one of > +which is assigned a unique pair of master and channel. While some of > +these masters and channels are statically allocated to certain > +hardware trace sources, others are available to software. Software > +trace sources are usually free to pick for themselves any > +master/channel combination from this pool. > + > +On the receiving end of this STP stream (the decoder side), trace > +sources can only be identified by master/channel combination, so in > +order for the decoder to be able to make sense of the trace that > +involves multiple trace sources, it needs to be able to map those > +master/channel pairs to the trace sources that it understands. > + > +For instance, it is helpful to know that syslog messages come on > +master 7 channel 15, while arbitrary user applications can use masters > +48 to 63 and channels 0 to 127. > + > +To solve this mapping problem, stm class provides a policy management > +mechanism via configfs, that allows defining rules that map string > +identifiers to ranges of masters and channels. If these rules (policy) > +are consistent with what decoder expects, it will be able to properly > +process the trace data. > + > +This policy is a tree structure containing rules (policy_node) that > +have a name (string identifier) and a range of masters and channels > +associated with it, located in "stp-policy" subsystem directory in > +configfs. The topmost directory's name (the policy) is formatted as > +the STM device name to which this policy applies and and arbitrary > +string identifier separated by a stop. From the examle above, a rule > +may look like this: > + > +$ ls /config/stp-policy/dummy_stm.my-policy/user > +channels masters > +$ cat /config/stp-policy/dummy_stm.my-policy/user/masters > +48 63 > +$ cat /config/stp-policy/dummy_stm.my-policy/user/channels > +0 127 > + > +which means that the master allocation pool for this rule consists of > +masters 48 through 63 and channel allocation pool has channels 0 > +through 127 in it. Now, any producer (trace source) identifying itself > +with "user" identification string will be allocated a master and > +channel from within these ranges. > + > +These rules can be nested, for example, one can define a rule "dummy" > +under "user" directory from the example above and this new rule will > +be used for trace sources with the id string of "user/dummy". > + > +Trace sources have to open the stm class device's node and write their > +trace data into its file descriptor. In order to identify themselves > +to the policy, they need to do a STP_POLICY_ID_SET ioctl on this file > +descriptor providing their id string. Otherwise, they will be > +automatically allocated a master/channel pair upon first write to this > +file descriptor according to the "default" rule of the policy, if such > +exists. > + > +Some STM devices may allow direct mapping of the channel mmio regions > +to userspace for zero-copy writing. One mappable page (in terms of > +mmu) will usually contain multiple channels' mmios, so the user will > +need to allocate that many channels to themselves (via the > +aforementioned ioctl() call) to be able to do this. That is, if your > +stm device's channel mmio region is 64 bytes and hardware page size is > +4096 bytes, after a successful STP_POLICY_ID_SET ioctl() call with > +width==64, you should be able to mmap() one page on this file > +descriptor and obtain direct access to an mmio region for 64 channels. > + > +For kernel-based trace sources, there is "stm_source" device > +class. Devices of this class can be connected and disconnected to/from > +stm devices at runtime via a sysfs attribute. > + > +Examples of STM devices are Intel Trace Hub [1] and Coresight STM > +[2]. > + > +[1] https://software.intel.com/sites/default/files/managed/d3/3c/intel-th-developer-manual.pdf > +[2] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0444b/index.html > diff --git a/drivers/Kconfig b/drivers/Kconfig > index 6e973b8e3a..96efe4522c 100644 > --- a/drivers/Kconfig > +++ b/drivers/Kconfig > @@ -184,4 +184,6 @@ source "drivers/android/Kconfig" > > source "drivers/nvdimm/Kconfig" > > +source "drivers/hwtracing/stm/Kconfig" > + > endmenu > diff --git a/drivers/Makefile b/drivers/Makefile > index b64b49f6e0..6647bc923f 100644 > --- a/drivers/Makefile > +++ b/drivers/Makefile > @@ -164,4 +164,5 @@ obj-$(CONFIG_MCB) += mcb/ > obj-$(CONFIG_RAS) += ras/ > obj-$(CONFIG_THUNDERBOLT) += thunderbolt/ > obj-$(CONFIG_CORESIGHT) += hwtracing/coresight/ > +obj-$(CONFIG_STM) += hwtracing/stm/ > obj-$(CONFIG_ANDROID) += android/ > diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig > new file mode 100644 > index 0000000000..90ed327461 > --- /dev/null > +++ b/drivers/hwtracing/stm/Kconfig > @@ -0,0 +1,8 @@ > +config STM > + tristate "System Trace Module devices" > + help > + A System Trace Module (STM) is a device exporting data in System > + Trace Protocol (STP) format as defined by MIPI STP standards. > + Examples of such devices are Intel Trace Hub and Coresight STM. > + > + Say Y here to enable System Trace Module device support. > diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile > new file mode 100644 > index 0000000000..adec701649 > --- /dev/null > +++ b/drivers/hwtracing/stm/Makefile > @@ -0,0 +1,3 @@ > +obj-$(CONFIG_STM) += stm_core.o > + > +stm_core-y := core.o policy.o > diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c > new file mode 100644 > index 0000000000..b79c42c625 > --- /dev/null > +++ b/drivers/hwtracing/stm/core.c > @@ -0,0 +1,1029 @@ > +/* > + * System Trace Module (STM) infrastructure > + * Copyright (c) 2014, Intel Corporation. > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * This program is distributed in the hope it will be useful, but WITHOUT > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > + * more details. > + * > + * STM class implements generic infrastructure for System Trace Module devices > + * as defined in MIPI STPv2 specification. > + */ > + > +#include <linux/uaccess.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/device.h> > +#include <linux/compat.h> > +#include <linux/kdev_t.h> > +#include <linux/srcu.h> > +#include <linux/slab.h> > +#include <linux/stm.h> > +#include <linux/fs.h> > +#include <linux/mm.h> > +#include "stm.h" > + > +#include <uapi/linux/stm.h> > + > +static unsigned int stm_core_up; > + > +/* > + * The SRCU here makes sure that STM device doesn't disappear from under a > + * stm_source_write() caller, which may want to have as little overhead as > + * possible. > + */ > +static struct srcu_struct stm_source_srcu; > + > +static ssize_t masters_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct stm_device *stm = to_stm_device(dev); > + int ret; > + > + ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end); > + > + return ret; > +} > + > +static DEVICE_ATTR_RO(masters); > + > +static ssize_t channels_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct stm_device *stm = to_stm_device(dev); > + int ret; > + > + ret = sprintf(buf, "%u\n", stm->data->sw_nchannels); > + > + return ret; > +} > + > +static DEVICE_ATTR_RO(channels); > + > +static struct attribute *stm_attrs[] = { > + &dev_attr_masters.attr, > + &dev_attr_channels.attr, > + NULL, > +}; > + > +ATTRIBUTE_GROUPS(stm); > + > +static struct class stm_class = { > + .name = "stm", > + .dev_groups = stm_groups, > +}; > + > +static int stm_dev_match(struct device *dev, const void *data) > +{ > + const char *name = data; > + > + return sysfs_streq(name, dev_name(dev)); > +} > + > +/** > + * stm_find_device() - find stm device by name > + * @buf: character buffer containing the name > + * > + * This is called when either policy gets assigned to an stm device or an > + * stm_source device gets linked to an stm device. > + * > + * This grabs device's reference (get_device()) and module reference, both > + * of which the calling path needs to make sure to drop with stm_put_device(). > + * > + * Return: stm device pointer or null if lookup failed. > + */ > +struct stm_device *stm_find_device(const char *buf) > +{ > + struct stm_device *stm; > + struct device *dev; > + > + if (!stm_core_up) > + return NULL; > + > + dev = class_find_device(&stm_class, NULL, buf, stm_dev_match); > + if (!dev) > + return NULL; > + > + stm = to_stm_device(dev); > + if (!try_module_get(stm->owner)) { > + put_device(dev); > + return NULL; > + } > + > + return stm; > +} > + > +/** > + * stm_put_device() - drop references on the stm device > + * @stm: stm device, previously acquired by stm_find_device() > + * > + * This drops the module reference and device reference taken by > + * stm_find_device(). > + */ > +void stm_put_device(struct stm_device *stm) > +{ > + module_put(stm->owner); > + put_device(&stm->dev); > +} > + > +/* > + * Internally we only care about software-writable masters here, that is the > + * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need > + * original master numbers to be visible externally, since they are the ones > + * that will appear in the STP stream. Thus, the internal bookkeeping uses > + * $master - stm_data->sw_start to reference master descriptors and such. > + */ > + > +#define __stm_master(_s, _m) \ > + ((_s)->masters[(_m) - (_s)->data->sw_start]) > + > +static inline struct stp_master * > +stm_master(struct stm_device *stm, unsigned int idx) > +{ > + if (idx < stm->data->sw_start || idx > stm->data->sw_end) > + return NULL; > + > + return __stm_master(stm, idx); > +} > + > +static int stp_master_alloc(struct stm_device *stm, unsigned int idx) > +{ > + struct stp_master *master; > + size_t size; > + > + size = ALIGN(stm->data->sw_nchannels, 8) / 8; > + size += sizeof(struct stp_master); > + master = kzalloc(size, GFP_ATOMIC); > + if (!master) > + return -ENOMEM; > + > + master->nr_free = stm->data->sw_nchannels; > + __stm_master(stm, idx) = master; > + > + return 0; > +} > + > +static void stp_master_free(struct stm_device *stm, unsigned int idx) > +{ > + struct stp_master *master = stm_master(stm, idx); > + > + if (!master) > + return; > + > + __stm_master(stm, idx) = NULL; > + kfree(master); > +} > + > +static void stm_output_claim(struct stm_device *stm, struct stm_output *output) > +{ > + struct stp_master *master = stm_master(stm, output->master); > + > + if (WARN_ON_ONCE(master->nr_free < output->nr_chans)) > + return; > + > + bitmap_allocate_region(&master->chan_map[0], output->channel, > + ilog2(output->nr_chans)); > + > + master->nr_free -= output->nr_chans; > +} > + > +static void > +stm_output_disclaim(struct stm_device *stm, struct stm_output *output) > +{ > + struct stp_master *master = stm_master(stm, output->master); > + > + bitmap_release_region(&master->chan_map[0], output->channel, > + ilog2(output->nr_chans)); > + > + output->nr_chans = 0; > + master->nr_free += output->nr_chans; > +} > + > +/* > + * This is like bitmap_find_free_region(), except it can ignore @start bits > + * at the beginning. > + */ > +static int find_free_channels(unsigned long *bitmap, unsigned int start, > + unsigned int end, unsigned int width) > +{ > + unsigned int pos; > + int i; > + > + for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) { > + pos = find_next_zero_bit(bitmap, end + 1, pos); > + if (pos + width > end + 1) > + break; > + > + if (pos & (width - 1)) > + continue; > + > + for (i = 1; i < width && !test_bit(pos + i, bitmap); i++) > + ; > + if (i == width) > + return pos; > + } > + > + return -1; > +} > + > +static unsigned int > +stm_find_master_chan(struct stm_device *stm, unsigned int width, > + unsigned int *mstart, unsigned int mend, > + unsigned int *cstart, unsigned int cend) > +{ > + struct stp_master *master; > + unsigned int midx; > + int pos, err; > + > + for (midx = *mstart; midx <= mend; midx++) { > + if (!stm_master(stm, midx)) { > + err = stp_master_alloc(stm, midx); > + if (err) > + return err; > + } > + > + master = stm_master(stm, midx); > + > + if (!master->nr_free) > + continue; > + > + pos = find_free_channels(master->chan_map, *cstart, cend, > + width); > + if (pos < 0) > + continue; > + > + *mstart = midx; > + *cstart = pos; > + return 0; > + } > + > + return -ENOSPC; > +} > + > +static int stm_output_assign(struct stm_device *stm, unsigned int width, > + struct stp_policy_node *policy_node, > + struct stm_output *output) > +{ > + unsigned int midx, cidx, mend, cend; > + int ret = -EINVAL; > + > + if (width > stm->data->sw_nchannels) > + return -EINVAL; > + > + if (policy_node) { > + stp_policy_node_get_ranges(policy_node, > + &midx, &mend, &cidx, &cend); > + } else { > + midx = stm->data->sw_start; > + cidx = 0; > + mend = stm->data->sw_end; > + cend = stm->data->sw_nchannels - 1; > + } > + > + spin_lock(&stm->mc_lock); > + /* output is already assigned -- shouldn't happen */ > + if (WARN_ON_ONCE(output->nr_chans)) > + goto unlock; > + > + ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend); > + if (ret) > + goto unlock; > + > + output->master = midx; > + output->channel = cidx; > + output->nr_chans = width; > + stm_output_claim(stm, output); > + dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width); > + > + ret = 0; > +unlock: > + spin_unlock(&stm->mc_lock); > + > + return ret; > +} > + > +static void stm_output_free(struct stm_device *stm, struct stm_output *output) > +{ > + spin_lock(&stm->mc_lock); > + if (output->nr_chans) > + stm_output_disclaim(stm, output); > + spin_unlock(&stm->mc_lock); > +} > + > +static int major_match(struct device *dev, const void *data) > +{ > + unsigned int major = *(unsigned int *)data; > + > + return MAJOR(dev->devt) == major; > +} > + > +static int stm_char_open(struct inode *inode, struct file *file) > +{ > + struct stm_file *stmf; > + struct device *dev; > + unsigned int major = imajor(inode); > + int err = -ENODEV; > + > + dev = class_find_device(&stm_class, NULL, &major, major_match); > + if (!dev) > + return -ENODEV; > + > + stmf = kzalloc(sizeof(*stmf), GFP_KERNEL); > + if (!stmf) > + return -ENOMEM; > + > + stmf->stm = to_stm_device(dev); > + > + if (!try_module_get(stmf->stm->owner)) > + goto err_free; > + > + file->private_data = stmf; > + > + return nonseekable_open(inode, file); > + > +err_free: > + kfree(stmf); > + > + return err; > +} > + > +static int stm_char_release(struct inode *inode, struct file *file) > +{ > + struct stm_file *stmf = file->private_data; > + > + stm_output_free(stmf->stm, &stmf->output); > + stm_put_device(stmf->stm); > + kfree(stmf); > + > + return 0; > +} > + > +static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width) > +{ > + struct stm_device *stm = stmf->stm; > + int ret; > + > + stmf->policy_node = stp_policy_node_lookup(stm, id); > + > + ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output); > + > + if (stmf->policy_node) > + stp_policy_node_put(stmf->policy_node); > + > + return ret; > +} > + > +static void stm_write(struct stm_data *data, unsigned int master, > + unsigned int channel, const char *buf, size_t count) > +{ > + unsigned int flags = STP_PACKET_TIMESTAMPED; > + const unsigned char *p = buf, nil = 0; > + size_t pos; > + ssize_t sz; > + > + for (pos = 0, p = buf; count > pos; pos += sz, p += sz) { > + sz = min_t(unsigned int, count - pos, 8); > + sz = data->packet(data, master, channel, STP_PACKET_DATA, flags, > + sz, p); > + flags = 0; > + } > + > + data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil); > +} > + > +static ssize_t stm_char_write(struct file *file, const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + struct stm_file *stmf = file->private_data; > + struct stm_device *stm = stmf->stm; > + char *kbuf; > + int err; > + > + /* > + * if no m/c have been assigned to this writer up to this > + * point, use "default" policy entry > + */ > + if (!stmf->output.nr_chans) { > + err = stm_file_assign(stmf, "default", 1); > + /* > + * EBUSY means that somebody else just assigned this > + * output, which is just fine for write() > + */ > + if (err && err != -EBUSY) > + return err; > + } > + > + kbuf = kmalloc(count + 1, GFP_KERNEL); > + if (!kbuf) > + return -ENOMEM; > + > + err = copy_from_user(kbuf, buf, count); > + if (err) { > + kfree(kbuf); > + return -EFAULT; > + } > + > + stm_write(stm->data, stmf->output.master, stmf->output.channel, kbuf, > + count); > + > + kfree(kbuf); > + > + return count; > +} > + > +static int stm_char_mmap(struct file *file, struct vm_area_struct *vma) > +{ > + struct stm_file *stmf = file->private_data; > + struct stm_device *stm = stmf->stm; > + unsigned long size, phys; > + > + if (!stm->data->mmio_addr) > + return -EOPNOTSUPP; > + > + if (vma->vm_pgoff) > + return -EINVAL; > + > + size = vma->vm_end - vma->vm_start; > + > + if (stmf->output.nr_chans * stm->data->sw_mmiosz != size) > + return -EINVAL; > + > + phys = stm->data->mmio_addr(stm->data, stmf->output.master, > + stmf->output.channel, > + stmf->output.nr_chans); > + > + if (!phys) > + return -EINVAL; > + > + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); > + vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; > + vm_iomap_memory(vma, phys, size); > + > + return 0; > +} > + > +static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg) > +{ > + struct stm_device *stm = stmf->stm; > + struct stp_policy_id *id; > + int ret = -EINVAL; > + u32 size; > + > + if (stmf->output.nr_chans) > + return -EBUSY; > + > + if (copy_from_user(&size, arg, sizeof(size))) > + return -EFAULT; > + > + if (size >= PATH_MAX + sizeof(*id)) > + return -EINVAL; > + > + /* > + * size + 1 to make sure the .id string at the bottom is terminated, > + * which is also why memdup_user() is not useful here > + */ > + id = kzalloc(size + 1, GFP_KERNEL); > + if (!id) > + return -ENOMEM; > + > + if (copy_from_user(id, arg, size)) { > + ret = -EFAULT; > + goto err_free; > + } > + > + if (id->__reserved_0 || id->__reserved_1) > + goto err_free; > + > + if (id->width < 1 || > + id->width > PAGE_SIZE / stm->data->sw_mmiosz) > + goto err_free; > + > + ret = stm_file_assign(stmf, id->id, id->width); > + if (ret) > + goto err_free; > + > + ret = 0; > + > + if (stm->data->link) > + ret = stm->data->link(stm->data, stmf->output.master, > + stmf->output.channel); > + > + if (ret) { > + stm_output_free(stmf->stm, &stmf->output); > + stm_put_device(stmf->stm); > + } > + > +err_free: > + kfree(id); > + > + return ret; > +} > + > +static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg) > +{ > + struct stp_policy_id id = { > + .size = sizeof(id), > + .master = stmf->output.master, > + .channel = stmf->output.channel, > + .width = stmf->output.nr_chans, > + .__reserved_0 = 0, > + .__reserved_1 = 0, > + }; > + > + return copy_to_user(arg, &id, id.size) ? -EFAULT : 0; > +} > + > +static long > +stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > +{ > + struct stm_file *stmf = file->private_data; > + struct stm_data *stm_data = stmf->stm->data; > + int err = -ENOTTY; > + u64 options; > + > + switch (cmd) { > + case STP_POLICY_ID_SET: > + err = stm_char_policy_set_ioctl(stmf, (void __user *)arg); > + if (err) > + return err; > + > + return stm_char_policy_get_ioctl(stmf, (void __user *)arg); > + > + case STP_POLICY_ID_GET: > + return stm_char_policy_get_ioctl(stmf, (void __user *)arg); > + > + case STP_SET_OPTIONS: > + if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64))) > + return -EFAULT; > + > + if (stm_data->set_options) > + err = stm_data->set_options(stm_data, > + stmf->output.master, > + stmf->output.channel, > + stmf->output.nr_chans, > + options); > + > + break; > + default: > + break; > + } > + > + return err; > +} > + > +#ifdef CONFIG_COMPAT > +static long > +stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > +{ > + return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); > +} > +#else > +#define stm_char_compat_ioctl NULL > +#endif > + > +static const struct file_operations stm_fops = { > + .open = stm_char_open, > + .release = stm_char_release, > + .write = stm_char_write, > + .mmap = stm_char_mmap, > + .unlocked_ioctl = stm_char_ioctl, > + .compat_ioctl = stm_char_compat_ioctl, > + .llseek = no_llseek, > +}; > + > +static void stm_device_release(struct device *dev) > +{ > + struct stm_device *stm = to_stm_device(dev); > + > + kfree(stm); > +} > + > +int stm_register_device(struct device *parent, struct stm_data *stm_data, > + struct module *owner) > +{ > + struct stm_device *stm; > + unsigned int nmasters; > + int err = -ENOMEM; > + > + if (!stm_core_up) > + return -EPROBE_DEFER; > + > + if (!stm_data->packet || !stm_data->sw_nchannels) > + return -EINVAL; > + > + nmasters = stm_data->sw_end - stm_data->sw_start; > + stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL); > + if (!stm) > + return -ENOMEM; > + > + stm->major = register_chrdev(0, stm_data->name, &stm_fops); > + if (stm->major < 0) > + goto err_free; > + > + device_initialize(&stm->dev); > + stm->dev.devt = MKDEV(stm->major, 0); > + stm->dev.class = &stm_class; > + stm->dev.parent = parent; > + stm->dev.release = stm_device_release; > + > + err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name); > + if (err) > + goto err_device; > + > + err = device_add(&stm->dev); > + if (err) > + goto err_device; > + > + spin_lock_init(&stm->link_lock); > + INIT_LIST_HEAD(&stm->link_list); > + > + spin_lock_init(&stm->mc_lock); > + mutex_init(&stm->policy_mutex); > + stm->sw_nmasters = nmasters; > + stm->owner = owner; > + stm->data = stm_data; > + stm_data->stm = stm; > + > + return 0; > + > +err_device: > + put_device(&stm->dev); > +err_free: > + kfree(stm); > + > + return err; > +} > +EXPORT_SYMBOL_GPL(stm_register_device); > + > +static void __stm_source_link_drop(struct stm_source_device *src, > + struct stm_device *stm); > + > +void stm_unregister_device(struct stm_data *stm_data) > +{ > + struct stm_device *stm = stm_data->stm; > + struct stm_source_device *src, *iter; > + int i; > + > + spin_lock(&stm->link_lock); > + list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) { > + __stm_source_link_drop(src, stm); > + } > + spin_unlock(&stm->link_lock); > + > + synchronize_srcu(&stm_source_srcu); > + > + unregister_chrdev(stm->major, stm_data->name); > + > + mutex_lock(&stm->policy_mutex); > + if (stm->policy) > + stp_policy_unbind(stm->policy); > + mutex_unlock(&stm->policy_mutex); > + > + for (i = 0; i < stm->sw_nmasters; i++) > + stp_master_free(stm, i); > + > + device_unregister(&stm->dev); > + stm_data->stm = NULL; > +} > +EXPORT_SYMBOL_GPL(stm_unregister_device); > + > +/** > + * stm_source_link_add() - connect an stm_source device to an stm device > + * @src: stm_source device > + * @stm: stm device > + * > + * This function establishes a link from stm_source to an stm device so that > + * the former can send out trace data to the latter. > + * > + * Return: 0 on success, -errno otherwise. > + */ > +static int stm_source_link_add(struct stm_source_device *src, > + struct stm_device *stm) > +{ > + char *id; > + int err; > + > + spin_lock(&stm->link_lock); > + spin_lock(&src->link_lock); > + > + /* src->link is dereferenced under stm_source_srcu but not the list */ > + rcu_assign_pointer(src->link, stm); > + list_add_tail(&src->link_entry, &stm->link_list); > + > + spin_unlock(&src->link_lock); > + spin_unlock(&stm->link_lock); > + > + id = kstrdup(src->data->name, GFP_KERNEL); > + if (id) { > + src->policy_node = > + stp_policy_node_lookup(stm, id); > + > + kfree(id); > + } > + > + err = stm_output_assign(stm, src->data->nr_chans, > + src->policy_node, &src->output); > + > + if (src->policy_node) > + stp_policy_node_put(src->policy_node); > + > + if (err) > + goto fail_detach; > + > + /* this is to notify the STM device that a new link has been made */ > + if (stm->data->link) > + err = stm->data->link(stm->data, src->output.master, > + src->output.channel); > + > + if (err) > + goto fail_free_output; > + > + /* this is to let the source carry out all necessary preparations */ > + if (src->data->link) > + src->data->link(src->data); > + > + return 0; > + > +fail_free_output: > + stm_output_free(stm, &src->output); > + stm_put_device(stm); > + > +fail_detach: > + spin_lock(&stm->link_lock); > + spin_lock(&src->link_lock); > + > + rcu_assign_pointer(src->link, NULL); > + list_del_init(&src->link_entry); > + > + spin_unlock(&src->link_lock); > + spin_unlock(&stm->link_lock); > + > + return err; > +} > + > +/** > + * __stm_source_link_drop() - detach stm_source from an stm device > + * @src: stm_source device > + * @stm: stm device > + * > + * If @stm is @src::link, disconnect them from one another and put the > + * reference on the @stm device. > + * > + * Caller must hold stm::link_lock. > + */ > +static void __stm_source_link_drop(struct stm_source_device *src, > + struct stm_device *stm) > +{ > + spin_lock(&src->link_lock); > + if (WARN_ON_ONCE(src->link != stm)) { > + spin_unlock(&src->link_lock); > + return; > + } > + > + stm_output_free(src->link, &src->output); > + /* caller must hold stm::link_lock */ > + list_del_init(&src->link_entry); > + /* matches stm_find_device() from stm_source_link_store() */ > + stm_put_device(src->link); > + rcu_assign_pointer(src->link, NULL); > + > + spin_unlock(&src->link_lock); > +} > + > +/** > + * stm_source_link_drop() - detach stm_source from its stm device > + * @src: stm_source device > + * > + * Unlinking means disconnecting from source's STM device; after this > + * writes will be unsuccessful until it is linked to a new STM device. > + * > + * This will happen on "stm_source_link" sysfs attribute write to undo > + * the existing link (if any), or on linked STM device's de-registration. > + */ > +static void stm_source_link_drop(struct stm_source_device *src) > +{ > + struct stm_device *stm; > + int idx; > + > + idx = srcu_read_lock(&stm_source_srcu); > + stm = srcu_dereference(src->link, &stm_source_srcu); > + > + if (stm) { > + if (src->data->unlink) > + src->data->unlink(src->data); > + > + spin_lock(&stm->link_lock); > + __stm_source_link_drop(src, stm); > + spin_unlock(&stm->link_lock); > + } > + > + srcu_read_unlock(&stm_source_srcu, idx); > +} > + > +static ssize_t stm_source_link_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct stm_source_device *src = to_stm_source_device(dev); > + struct stm_device *stm; > + int idx, ret; > + > + idx = srcu_read_lock(&stm_source_srcu); > + stm = srcu_dereference(src->link, &stm_source_srcu); > + ret = sprintf(buf, "%s\n", > + stm ? dev_name(&stm->dev) : "<none>"); > + srcu_read_unlock(&stm_source_srcu, idx); > + > + return ret; > +} > + > +static ssize_t stm_source_link_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct stm_source_device *src = to_stm_source_device(dev); > + struct stm_device *link; > + int err; > + > + stm_source_link_drop(src); > + > + link = stm_find_device(buf); > + if (!link) > + return -EINVAL; > + > + err = stm_source_link_add(src, link); > + if (err) > + stm_put_device(link); > + > + return err ? : count; > +} > + > +static DEVICE_ATTR_RW(stm_source_link); > + > +static struct attribute *stm_source_attrs[] = { > + &dev_attr_stm_source_link.attr, > + NULL, > +}; > + > +ATTRIBUTE_GROUPS(stm_source); > + > +static struct class stm_source_class = { > + .name = "stm_source", > + .dev_groups = stm_source_groups, > +}; > + > +static void stm_source_device_release(struct device *dev) > +{ > + struct stm_source_device *src = to_stm_source_device(dev); > + > + kfree(src); > +} > + > +/** > + * stm_source_register_device() - register an stm_source device > + * @parent: parent device > + * @data: device description structure > + * > + * This will create a device of stm_source class that can write > + * data to an stm device once linked. > + * > + * Return: 0 on success, -errno otherwise. > + */ > +int stm_source_register_device(struct device *parent, > + struct stm_source_data *data) > +{ > + struct stm_source_device *src; > + int err; > + > + if (!stm_core_up) > + return -EPROBE_DEFER; > + I tried to update Coresight-stm driver[1] based on your this version patch, but the Coresight-stm driver probe() failed. the reason was: In the end of Coresight stm_probe(), we called this function, but "stm_core_up" was zero then, so the error returned value "-EPROBE_DEFER" was received. In fact, "stm_core_up" would increase itself until "stm_core_init" be called - it's the root of this problem, I'll explain this where the function "stm_core_init" defined. And redoing Coresight stm_probe() will incur a WARN_ON() like below: [ 1.075746] coresight-stm 10006000.stm: stm_register_device failed [ 1.082118] ------------[ cut here ]------------ [ 1.086819] WARNING: CPU: 1 PID: 1 at drivers/clk/clk.c:657 clk_core_disable+0x138/0x13c() [ 1.095353] Modules linked in: [ 1.098487] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G S 4.2.0-rc1+ #107 [ 1.106398] Hardware name: Spreadtrum SC9836 Openphone Board (DT) [ 1.112678] Call trace: [ 1.115194] [<ffffffc00008a5b4>] dump_backtrace+0x0/0x138 [ 1.120761] [<ffffffc00008a708>] show_stack+0x1c/0x28 [ 1.125972] [<ffffffc0003320e0>] dump_stack+0x84/0xc8 [ 1.131179] [<ffffffc00009b580>] warn_slowpath_common+0xa4/0xdc [ 1.137285] [<ffffffc00009b700>] warn_slowpath_null+0x34/0x44 [ 1.143213] [<ffffffc000321eb4>] clk_core_disable+0x134/0x13c [ 1.149140] [<ffffffc000322154>] clk_disable+0x30/0x48 [ 1.154439] [<ffffffc0002b5e58>] amba_put_disable_pclk.isra.6+0x20/0x40 [ 1.161264] [<ffffffc0002b6134>] amba_probe+0x16c/0x19c [ 1.166653] [<ffffffc0002e664c>] driver_probe_device+0x1a4/0x2b4 [ 1.172849] [<ffffffc0002e6804>] __driver_attach+0xa8/0xb0 [ 1.178506] [<ffffffc0002e45fc>] bus_for_each_dev+0x68/0xac [ 1.184253] [<ffffffc0002e60b4>] driver_attach+0x28/0x34 [ 1.189731] [<ffffffc0002e5cd0>] bus_add_driver+0x1cc/0x234 [ 1.195479] [<ffffffc0002e73d8>] driver_register+0x64/0x124 [ 1.201226] [<ffffffc0002b58cc>] amba_driver_register+0x64/0x74 [ 1.207333] [<ffffffc00045591c>] stm_driver_init+0x10/0x1c [ 1.212990] [<ffffffc0000828e0>] do_one_initcall+0x90/0x1a8 [ 1.218739] [<ffffffc000431adc>] kernel_init_freeable+0x150/0x1f4 [ 1.225026] [<ffffffc00032fbe4>] kernel_init+0x1c/0xe0 [ 1.230321] ---[ end trace 487f4b7838ebf86a ]--- [ 1.235102] ------------[ cut here ]------------ > + src = kzalloc(sizeof(*src), GFP_KERNEL); > + if (!src) > + return -ENOMEM; > + > + device_initialize(&src->dev); > + src->dev.class = &stm_source_class; > + src->dev.parent = parent; > + src->dev.release = stm_source_device_release; > + > + err = kobject_set_name(&src->dev.kobj, "%s", data->name); > + if (err) > + goto err; > + > + err = device_add(&src->dev); > + if (err) > + goto err; > + > + spin_lock_init(&src->link_lock); > + INIT_LIST_HEAD(&src->link_entry); > + src->data = data; > + data->src = src; > + > + return 0; > + > +err: > + put_device(&src->dev); > + kfree(src); > + > + return err; > +} > +EXPORT_SYMBOL_GPL(stm_source_register_device); > + > +/** > + * stm_source_unregister_device() - unregister an stm_source device > + * @data: device description that was used to register the device > + * > + * This will remove a previously created stm_source device from the system. > + */ > +void stm_source_unregister_device(struct stm_source_data *data) > +{ > + struct stm_source_device *src = data->src; > + > + stm_source_link_drop(src); > + > + device_destroy(&stm_source_class, src->dev.devt); > +} > +EXPORT_SYMBOL_GPL(stm_source_unregister_device); > + > +int stm_source_write(struct stm_source_data *data, unsigned int chan, > + const char *buf, size_t count) > +{ > + struct stm_source_device *src = data->src; > + struct stm_device *stm; > + int idx; > + > + if (!src->output.nr_chans) > + return -ENODEV; > + > + if (chan >= src->output.nr_chans) > + return -EINVAL; > + > + idx = srcu_read_lock(&stm_source_srcu); > + > + stm = srcu_dereference(src->link, &stm_source_srcu); > + if (stm) > + stm_write(stm->data, src->output.master, > + src->output.channel + chan, > + buf, count); > + else > + count = -ENODEV; > + > + srcu_read_unlock(&stm_source_srcu, idx); > + > + return count; > +} > +EXPORT_SYMBOL_GPL(stm_source_write); > + > +static int __init stm_core_init(void) > +{ > + int err; > + > + err = class_register(&stm_class); > + if (err) > + return err; > + > + err = class_register(&stm_source_class); > + if (err) > + goto err_stm; > + > + err = stp_configfs_init(); > + if (err) > + goto err_src; > + > + init_srcu_struct(&stm_source_srcu); > + > + stm_core_up++; > + > + return 0; > + > +err_src: > + class_unregister(&stm_source_class); > +err_stm: > + class_unregister(&stm_class); > + > + return err; > +} > + > +module_init(stm_core_init); Since you are using module_init() instead of postcore_initcall() which was in the last version patch, as such, this function would be executed after Coresight "stm_probe" finished. So, we think there a few optional solutions: 1) Remove the "stm_register_device" out from Coresight "stm_probe", but we have to save another global variable: struct device *stm_dev; in the process of Coresight "stm_probe". 2) Change module_init() to other XYX_init() which would run prior to "amba_probe()" (i.e. the caller of Coresight stm_probe), this may be a better one. 3) stm_core_init() could be turned into a library call where initialisation of the internals is done when first called. Looking forward to your reply/comments. Thanks, Chunyan [1] https://lkml.org/lkml/2015/2/4/729 > + > +static void __exit stm_core_exit(void) > +{ > + cleanup_srcu_struct(&stm_source_srcu); > + class_unregister(&stm_source_class); > + class_unregister(&stm_class); > + stp_configfs_exit(); > +} > + > +module_exit(stm_core_exit); > + > +MODULE_LICENSE("GPL v2"); > +MODULE_DESCRIPTION("System Trace Module device class"); > +MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>"); > diff --git a/drivers/hwtracing/stm/policy.c b/drivers/hwtracing/stm/policy.c > new file mode 100644 > index 0000000000..6498a9dbb7 > --- /dev/null > +++ b/drivers/hwtracing/stm/policy.c > @@ -0,0 +1,529 @@ > +/* > + * System Trace Module (STM) master/channel allocation policy management > + * Copyright (c) 2014, Intel Corporation. > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * This program is distributed in the hope it will be useful, but WITHOUT > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > + * more details. > + * > + * A master/channel allocation policy allows mapping string identifiers to > + * master and channel ranges, where allocation can be done. > + */ > + > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include <linux/types.h> > +#include <linux/module.h> > +#include <linux/device.h> > +#include <linux/configfs.h> > +#include <linux/slab.h> > +#include <linux/stm.h> > +#include "stm.h" > + > +/* > + * STP Master/Channel allocation policy configfs layout. > + */ > + > +struct stp_policy { > + struct config_group group; > + struct stm_device *stm; > +}; > + > +struct stp_policy_node { > + struct config_group group; > + struct stp_policy *policy; > + unsigned int first_master; > + unsigned int last_master; > + unsigned int first_channel; > + unsigned int last_channel; > +}; > + > +static struct configfs_subsystem stp_policy_subsys; > + > +void stp_policy_node_get_ranges(struct stp_policy_node *policy_node, > + unsigned int *mstart, unsigned int *mend, > + unsigned int *cstart, unsigned int *cend) > +{ > + *mstart = policy_node->first_master; > + *mend = policy_node->last_master; > + *cstart = policy_node->first_channel; > + *cend = policy_node->last_channel; > +} > + > +static inline char *stp_policy_node_name(struct stp_policy_node *policy_node) > +{ > + return policy_node->group.cg_item.ci_name ? : "<none>"; > +} > + > +static inline struct stp_policy *to_stp_policy(struct config_item *item) > +{ > + return item ? > + container_of(to_config_group(item), struct stp_policy, group) : > + NULL; > +} > + > +static inline struct stp_policy_node * > +to_stp_policy_node(struct config_item *item) > +{ > + return item ? > + container_of(to_config_group(item), struct stp_policy_node, > + group) : > + NULL; > +} > + > +static ssize_t stp_policy_node_masters_show(struct stp_policy_node *policy_node, > + char *page) > +{ > + ssize_t count; > + > + count = sprintf(page, "%u %u\n", policy_node->first_master, > + policy_node->last_master); > + > + return count; > +} > + > +static ssize_t > +stp_policy_node_masters_store(struct stp_policy_node *policy_node, > + const char *page, size_t count) > +{ > + unsigned int first, last; > + struct stm_device *stm; > + char *p = (char *)page; > + ssize_t ret = -ENODEV; > + > + if (sscanf(p, "%u %u", &first, &last) != 2) > + return -EINVAL; > + > + mutex_lock(&stp_policy_subsys.su_mutex); > + stm = policy_node->policy->stm; > + if (!stm) > + goto unlock; > + > + /* must be within [sw_start..sw_end], which is an inclusive range */ > + if (first > INT_MAX || last > INT_MAX || first > last || > + first < stm->data->sw_start || > + last > stm->data->sw_end) { > + ret = -ERANGE; > + goto unlock; > + } > + > + ret = count; > + policy_node->first_master = first; > + policy_node->last_master = last; > + > +unlock: > + mutex_unlock(&stp_policy_subsys.su_mutex); > + > + return ret; > +} > + > +static ssize_t > +stp_policy_node_channels_show(struct stp_policy_node *policy_node, char *page) > +{ > + ssize_t count; > + > + count = sprintf(page, "%u %u\n", policy_node->first_channel, > + policy_node->last_channel); > + > + return count; > +} > + > +static ssize_t > +stp_policy_node_channels_store(struct stp_policy_node *policy_node, > + const char *page, size_t count) > +{ > + unsigned int first, last; > + struct stm_device *stm; > + char *p = (char *)page; > + ssize_t ret = -ENODEV; > + > + if (sscanf(p, "%u %u", &first, &last) != 2) > + return -EINVAL; > + > + mutex_lock(&stp_policy_subsys.su_mutex); > + stm = policy_node->policy->stm; > + if (!stm) > + goto unlock; > + > + if (first > INT_MAX || last > INT_MAX || first > last || > + last >= stm->data->sw_nchannels) { > + ret = -ERANGE; > + goto unlock; > + } > + > + ret = count; > + policy_node->first_channel = first; > + policy_node->last_channel = last; > + > +unlock: > + mutex_unlock(&stp_policy_subsys.su_mutex); > + > + return ret; > +} > + > +static void stp_policy_node_release(struct config_item *item) > +{ > + kfree(to_stp_policy_node(item)); > +} > + > +struct stp_policy_node_attribute { > + struct configfs_attribute attr; > + ssize_t (*show)(struct stp_policy_node *, char *); > + ssize_t (*store)(struct stp_policy_node *, const char *, size_t); > +}; > + > +static ssize_t stp_policy_node_attr_show(struct config_item *item, > + struct configfs_attribute *attr, > + char *page) > +{ > + struct stp_policy_node *policy_node = to_stp_policy_node(item); > + struct stp_policy_node_attribute *pn_attr = > + container_of(attr, struct stp_policy_node_attribute, attr); > + ssize_t count = 0; > + > + if (pn_attr->show) > + count = pn_attr->show(policy_node, page); > + > + return count; > +} > + > +static ssize_t stp_policy_node_attr_store(struct config_item *item, > + struct configfs_attribute *attr, > + const char *page, size_t len) > +{ > + struct stp_policy_node *policy_node = to_stp_policy_node(item); > + struct stp_policy_node_attribute *pn_attr = > + container_of(attr, struct stp_policy_node_attribute, attr); > + ssize_t count = -EINVAL; > + > + if (pn_attr->store) > + count = pn_attr->store(policy_node, page, len); > + > + return count; > +} > + > +static struct configfs_item_operations stp_policy_node_item_ops = { > + .release = stp_policy_node_release, > + .show_attribute = stp_policy_node_attr_show, > + .store_attribute = stp_policy_node_attr_store, > +}; > + > +static struct stp_policy_node_attribute stp_policy_node_attr_range = { > + .attr = { > + .ca_owner = THIS_MODULE, > + .ca_name = "masters", > + .ca_mode = S_IRUGO | S_IWUSR, > + }, > + .show = stp_policy_node_masters_show, > + .store = stp_policy_node_masters_store, > +}; > + > +static struct stp_policy_node_attribute stp_policy_node_attr_channels = { > + .attr = { > + .ca_owner = THIS_MODULE, > + .ca_name = "channels", > + .ca_mode = S_IRUGO | S_IWUSR, > + }, > + .show = stp_policy_node_channels_show, > + .store = stp_policy_node_channels_store, > +}; > + > +static struct configfs_attribute *stp_policy_node_attrs[] = { > + &stp_policy_node_attr_range.attr, > + &stp_policy_node_attr_channels.attr, > + NULL, > +}; > + > +static struct config_item_type stp_policy_type; > +static struct config_item_type stp_policy_node_type; > + > +static struct config_group * > +stp_policy_node_make(struct config_group *group, const char *name) > +{ > + struct stp_policy_node *policy_node, *parent_node; > + struct stp_policy *policy; > + > + if (group->cg_item.ci_type == &stp_policy_type) { > + policy = container_of(group, struct stp_policy, group); > + } else { > + parent_node = container_of(group, struct stp_policy_node, > + group); > + policy = parent_node->policy; > + } > + > + if (!policy->stm) > + return ERR_PTR(-ENODEV); > + > + policy_node = kzalloc(sizeof(struct stp_policy_node), GFP_KERNEL); > + if (!policy_node) > + return ERR_PTR(-ENOMEM); > + > + config_group_init_type_name(&policy_node->group, name, > + &stp_policy_node_type); > + > + policy_node->policy = policy; > + > + /* default values for the attributes */ > + policy_node->first_master = policy->stm->data->sw_start; > + policy_node->last_master = policy->stm->data->sw_end; > + policy_node->first_channel = 0; > + policy_node->last_channel = policy->stm->data->sw_nchannels - 1; > + > + return &policy_node->group; > +} > + > +static void > +stp_policy_node_drop(struct config_group *group, struct config_item *item) > +{ > + config_item_put(item); > +} > + > +static struct configfs_group_operations stp_policy_node_group_ops = { > + .make_group = stp_policy_node_make, > + .drop_item = stp_policy_node_drop, > +}; > + > +static struct config_item_type stp_policy_node_type = { > + .ct_item_ops = &stp_policy_node_item_ops, > + .ct_group_ops = &stp_policy_node_group_ops, > + .ct_attrs = stp_policy_node_attrs, > + .ct_owner = THIS_MODULE, > +}; > + > +/* > + * Root group: policies. > + */ > +static struct configfs_attribute stp_policy_attr_device = { > + .ca_owner = THIS_MODULE, > + .ca_name = "device", > + .ca_mode = S_IRUGO, > +}; > + > +static struct configfs_attribute *stp_policy_attrs[] = { > + &stp_policy_attr_device, > + NULL, > +}; > + > +static ssize_t stp_policy_attr_show(struct config_item *item, > + struct configfs_attribute *attr, > + char *page) > +{ > + struct stp_policy *policy = to_stp_policy(item); > + ssize_t count; > + > + count = sprintf(page, "%s\n", > + (policy && policy->stm) ? > + policy->stm->data->name : > + "<none>"); > + > + return count; > +} > + > +void stp_policy_unbind(struct stp_policy *policy) > +{ > + struct stm_device *stm = policy->stm; > + > + if (WARN_ON_ONCE(!policy->stm)) > + return; > + > + mutex_lock(&stm->policy_mutex); > + stm->policy = NULL; > + mutex_unlock(&stm->policy_mutex); > + > + policy->stm = NULL; > + > + stm_put_device(stm); > +} > + > +static void stp_policy_release(struct config_item *item) > +{ > + struct stp_policy *policy = to_stp_policy(item); > + > + stp_policy_unbind(policy); > + kfree(policy); > +} > + > +static struct configfs_item_operations stp_policy_item_ops = { > + .release = stp_policy_release, > + .show_attribute = stp_policy_attr_show, > +}; > + > +static struct configfs_group_operations stp_policy_group_ops = { > + .make_group = stp_policy_node_make, > +}; > + > +static struct config_item_type stp_policy_type = { > + .ct_item_ops = &stp_policy_item_ops, > + .ct_group_ops = &stp_policy_group_ops, > + .ct_attrs = stp_policy_attrs, > + .ct_owner = THIS_MODULE, > +}; > + > +static struct config_group * > +stp_policies_make(struct config_group *group, const char *name) > +{ > + struct config_group *ret; > + struct stm_device *stm; > + char *devname, *p; > + > + devname = kasprintf(GFP_KERNEL, "%s", name); > + if (!devname) > + return ERR_PTR(-ENOMEM); > + > + /* > + * node must look like <device_name>.<policy_name>, where > + * <device_name> is the name of an existing stm device and > + * <policy_name> is an arbitrary string > + */ > + p = strchr(devname, '.'); > + if (!p) { > + kfree(devname); > + return ERR_PTR(-EINVAL); > + } > + > + *p++ = '\0'; > + > + stm = stm_find_device(devname); > + kfree(devname); > + > + if (!stm) > + return ERR_PTR(-ENODEV); > + > + mutex_lock(&stm->policy_mutex); > + if (stm->policy) { > + ret = ERR_PTR(-EBUSY); > + goto unlock_policy; > + } > + > + stm->policy = kzalloc(sizeof(*stm->policy), GFP_KERNEL); > + if (!stm->policy) { > + ret = ERR_PTR(-ENOMEM); > + goto unlock_policy; > + } > + > + config_group_init_type_name(&stm->policy->group, name, > + &stp_policy_type); > + stm->policy->stm = stm; > + > + ret = &stm->policy->group; > + > +unlock_policy: > + mutex_unlock(&stm->policy_mutex); > + > + if (IS_ERR(ret)) > + stm_put_device(stm); > + > + return ret; > +} > + > +static struct configfs_group_operations stp_policies_group_ops = { > + .make_group = stp_policies_make, > +}; > + > +static struct config_item_type stp_policies_type = { > + .ct_group_ops = &stp_policies_group_ops, > + .ct_owner = THIS_MODULE, > +}; > + > +static struct configfs_subsystem stp_policy_subsys = { > + .su_group = { > + .cg_item = { > + .ci_namebuf = "stp-policy", > + .ci_type = &stp_policies_type, > + }, > + }, > +}; > + > +/* > + * Lock the policy mutex from the outside > + */ > +static struct stp_policy_node * > +__stp_policy_node_lookup(struct stp_policy *policy, char *s) > +{ > + struct stp_policy_node *policy_node, *ret; > + struct list_head *head = &policy->group.cg_children; > + struct config_item *item; > + char *start, *end = s; > + > + if (list_empty(head)) > + return NULL; > + > + /* return the first entry if everything else fails */ > + item = list_entry(head->next, struct config_item, ci_entry); > + ret = to_stp_policy_node(item); > + > +next: > + for (;;) { > + start = strsep(&end, "/"); > + if (!start) > + break; > + > + if (!*start) > + continue; > + > + list_for_each_entry(item, head, ci_entry) { > + policy_node = to_stp_policy_node(item); > + > + if (!strcmp(start, > + policy_node->group.cg_item.ci_name)) { > + ret = policy_node; > + > + if (!end) > + goto out; > + > + head = &policy_node->group.cg_children; > + goto next; > + } > + } > + break; > + } > + > +out: > + return ret; > +} > + > + > +struct stp_policy_node * > +stp_policy_node_lookup(struct stm_device *stm, char *s) > +{ > + struct stp_policy_node *policy_node = NULL; > + > + mutex_lock(&stp_policy_subsys.su_mutex); > + > + mutex_lock(&stm->policy_mutex); > + if (stm->policy) > + policy_node = __stp_policy_node_lookup(stm->policy, s); > + mutex_unlock(&stm->policy_mutex); > + > + if (policy_node) > + config_item_get(&policy_node->group.cg_item); > + mutex_unlock(&stp_policy_subsys.su_mutex); > + > + return policy_node; > +} > + > +void stp_policy_node_put(struct stp_policy_node *policy_node) > +{ > + config_item_put(&policy_node->group.cg_item); > +} > + > +int __init stp_configfs_init(void) > +{ > + int err; > + > + config_group_init(&stp_policy_subsys.su_group); > + mutex_init(&stp_policy_subsys.su_mutex); > + err = configfs_register_subsystem(&stp_policy_subsys); > + > + return err; > +} > + > +void __exit stp_configfs_exit(void) > +{ > + configfs_unregister_subsystem(&stp_policy_subsys); > +} > diff --git a/drivers/hwtracing/stm/stm.h b/drivers/hwtracing/stm/stm.h > new file mode 100644 > index 0000000000..cf33bf976a > --- /dev/null > +++ b/drivers/hwtracing/stm/stm.h > @@ -0,0 +1,87 @@ > +/* > + * System Trace Module (STM) infrastructure > + * Copyright (c) 2014, Intel Corporation. > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * This program is distributed in the hope it will be useful, but WITHOUT > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > + * more details. > + * > + * STM class implements generic infrastructure for System Trace Module devices > + * as defined in MIPI STPv2 specification. > + */ > + > +#ifndef _STM_STM_H_ > +#define _STM_STM_H_ > + > +struct stp_policy; > +struct stp_policy_node; > + > +struct stp_policy_node * > +stp_policy_node_lookup(struct stm_device *stm, char *s); > +void stp_policy_node_put(struct stp_policy_node *policy_node); > +void stp_policy_unbind(struct stp_policy *policy); > + > +void stp_policy_node_get_ranges(struct stp_policy_node *policy_node, > + unsigned int *mstart, unsigned int *mend, > + unsigned int *cstart, unsigned int *cend); > +int stp_configfs_init(void); > +void stp_configfs_exit(void); > + > +struct stp_master { > + unsigned int nr_free; > + unsigned long chan_map[0]; > +}; > + > +struct stm_device { > + struct device dev; > + struct module *owner; > + struct stp_policy *policy; > + struct mutex policy_mutex; > + int major; > + unsigned int sw_nmasters; > + struct stm_data *data; > + spinlock_t link_lock; > + struct list_head link_list; > + /* master allocation */ > + spinlock_t mc_lock; > + struct stp_master *masters[0]; > +}; > + > +#define to_stm_device(_d) \ > + container_of((_d), struct stm_device, dev) > + > +struct stm_output { > + unsigned int master; > + unsigned int channel; > + unsigned int nr_chans; > +}; > + > +struct stm_file { > + struct stm_device *stm; > + struct stp_policy_node *policy_node; > + struct stm_output output; > +}; > + > +struct stm_device *stm_find_device(const char *name); > +void stm_put_device(struct stm_device *stm); > + > +struct stm_source_device { > + struct device dev; > + struct stm_source_data *data; > + spinlock_t link_lock; > + struct stm_device *link; > + struct list_head link_entry; > + /* one output per stm_source device */ > + struct stp_policy_node *policy_node; > + struct stm_output output; > +}; > + > +#define to_stm_source_device(_d) \ > + container_of((_d), struct stm_source_device, dev) > + > +#endif /* _STM_STM_H_ */ > diff --git a/include/linux/stm.h b/include/linux/stm.h > new file mode 100644 > index 0000000000..9d0083d364 > --- /dev/null > +++ b/include/linux/stm.h > @@ -0,0 +1,126 @@ > +/* > + * System Trace Module (STM) infrastructure apis > + * Copyright (C) 2014 Intel Corporation. > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * This program is distributed in the hope it will be useful, but WITHOUT > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > + * more details. > + */ > + > +#ifndef _STM_H_ > +#define _STM_H_ > + > +#include <linux/device.h> > + > +/** > + * enum stp_packet_type - STP packets that an STM driver sends > + */ > +enum stp_packet_type { > + STP_PACKET_DATA = 0, > + STP_PACKET_FLAG, > + STP_PACKET_USER, > + STP_PACKET_MERR, > + STP_PACKET_GERR, > + STP_PACKET_TRIG, > + STP_PACKET_XSYNC, > +}; > + > +/** > + * enum stp_packet_flags - STP packet modifiers > + */ > +enum stp_packet_flags { > + STP_PACKET_MARKED = 0x1, > + STP_PACKET_TIMESTAMPED = 0x2, > +}; > + > +struct stp_policy; > + > +struct stm_device; > + > +/** > + * struct stm_data - STM device description and callbacks > + * @name: device name > + * @stm: internal structure, only used by stm class code > + * @sw_start: first STP master available to software > + * @sw_end: last STP master available to software > + * @sw_nchannels: number of STP channels per master > + * @sw_mmiosz: size of one channel's IO space, for mmap, optional > + * @packet: callback that sends an STP packet > + * @mmio_addr: mmap callback, optional > + * @link: called when a new stm_source gets linked to us, optional > + * @unlink: likewise for unlinking, again optional > + * @set_options: set device-specific options on a channel > + * > + * Fill out this structure before calling stm_register_device() to create > + * an STM device and stm_unregister_device() to destroy it. It will also be > + * passed back to @packet(), @mmio_addr(), @link(), @unlink() and @set_options() > + * callbacks. > + * > + * Normally, an STM device will have a range of masters available to software > + * and the rest being statically assigned to various hardware trace sources. > + * The former is defined by the the range [@sw_start..@sw_end] of the device > + * description. That is, the lowest master that can be allocated to software > + * writers is @sw_start and data from this writer will appear is @sw_start > + * master in the STP stream. > + */ > +struct stm_data { > + const char *name; > + struct stm_device *stm; > + unsigned int sw_start; > + unsigned int sw_end; > + unsigned int sw_nchannels; > + unsigned int sw_mmiosz; > + ssize_t (*packet)(struct stm_data *, unsigned int, > + unsigned int, unsigned int, > + unsigned int, unsigned int, > + const unsigned char *); > + phys_addr_t (*mmio_addr)(struct stm_data *, unsigned int, > + unsigned int, unsigned int); > + int (*link)(struct stm_data *, unsigned int, > + unsigned int); > + void (*unlink)(struct stm_data *, unsigned int, > + unsigned int); > + long (*set_options)(struct stm_data *, unsigned int, > + unsigned int, unsigned int, > + unsigned long); > +}; > + > +int stm_register_device(struct device *parent, struct stm_data *stm_data, > + struct module *owner); > +void stm_unregister_device(struct stm_data *stm_data); > + > +struct stm_source_device; > + > +/** > + * struct stm_source_data - STM source device description and callbacks > + * @name: device name, will be used for policy lookup > + * @src: internal structure, only used by stm class code > + * @nr_chans: number of channels to allocate > + * @link: called when this source gets linked to an STM device > + * @unlink: called when this source is about to get unlinked from its STM > + * > + * Fill in this structure before calling stm_source_register_device() to > + * register a source device. Also pass it to unregister and write calls. > + */ > +struct stm_source_data { > + const char *name; > + struct stm_source_device *src; > + unsigned int percpu; > + unsigned int nr_chans; > + int (*link)(struct stm_source_data *data); > + void (*unlink)(struct stm_source_data *data); > +}; > + > +int stm_source_register_device(struct device *parent, > + struct stm_source_data *data); > +void stm_source_unregister_device(struct stm_source_data *data); > + > +int stm_source_write(struct stm_source_data *data, unsigned int chan, > + const char *buf, size_t count); > + > +#endif /* _STM_H_ */ > diff --git a/include/uapi/linux/stm.h b/include/uapi/linux/stm.h > new file mode 100644 > index 0000000000..626a8d3f63 > --- /dev/null > +++ b/include/uapi/linux/stm.h > @@ -0,0 +1,50 @@ > +/* > + * System Trace Module (STM) userspace interfaces > + * Copyright (c) 2014, Intel Corporation. > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * This program is distributed in the hope it will be useful, but WITHOUT > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > + * more details. > + * > + * STM class implements generic infrastructure for System Trace Module devices > + * as defined in MIPI STPv2 specification. > + */ > + > +#ifndef _UAPI_LINUX_STM_H > +#define _UAPI_LINUX_STM_H > + > +#include <linux/types.h> > + > +/** > + * struct stp_policy_id - identification for the STP policy > + * @size: size of the structure including real id[] length > + * @master: assigned master > + * @channel: first assigned channel > + * @width: number of requested channels > + * @id: identification string > + * > + * User must calculate the total size of the structure and put it into > + * @size field, fill out the @id and desired @width. In return, kernel > + * fills out @master, @channel and @width. > + */ > +struct stp_policy_id { > + __u32 size; > + __u16 master; > + __u16 channel; > + __u16 width; > + /* padding */ > + __u16 __reserved_0; > + __u32 __reserved_1; > + char id[0]; > +}; > + > +#define STP_POLICY_ID_SET _IOWR('%', 0, struct stp_policy_id) > +#define STP_POLICY_ID_GET _IOR('%', 1, struct stp_policy_id) > +#define STP_SET_OPTIONS _IOW('%', 2, __u64) > + > +#endif /* _UAPI_LINUX_STM_H */ > -- > 2.1.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
