Hi Mathieu, On Fri, 14 Feb 2020 at 23:17, Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> wrote: > > On Tue, Feb 11, 2020 at 10:58:05AM +0000, Mike Leach wrote: > > To allow the connections between coresight components to be represented > > in sysfs, generic methods for creating sysfs links between two coresight > > devices are added. > > > > Signed-off-by: Mike Leach <mike.leach@xxxxxxxxxx> > > Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> > > --- > > drivers/hwtracing/coresight/Makefile | 3 +- > > drivers/hwtracing/coresight/coresight-priv.h | 4 + > > drivers/hwtracing/coresight/coresight-sysfs.c | 124 ++++++++++++++++++ > > include/linux/coresight.h | 20 +++ > > 4 files changed, 150 insertions(+), 1 deletion(-) > > create mode 100644 drivers/hwtracing/coresight/coresight-sysfs.c > > > > diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile > > index 0e3e72f0f510..19497d1d92bf 100644 > > --- a/drivers/hwtracing/coresight/Makefile > > +++ b/drivers/hwtracing/coresight/Makefile > > @@ -2,7 +2,8 @@ > > # > > # Makefile for CoreSight drivers. > > # > > -obj-$(CONFIG_CORESIGHT) += coresight.o coresight-etm-perf.o coresight-platform.o > > +obj-$(CONFIG_CORESIGHT) += coresight.o coresight-etm-perf.o \ > > + coresight-platform.o coresight-sysfs.o > > obj-$(CONFIG_CORESIGHT_LINK_AND_SINK_TMC) += coresight-tmc.o \ > > coresight-tmc-etf.o \ > > coresight-tmc-etr.o > > diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h > > index 1cad642f27aa..a4a658d46045 100644 > > --- a/drivers/hwtracing/coresight/coresight-priv.h > > +++ b/drivers/hwtracing/coresight/coresight-priv.h > > @@ -153,6 +153,10 @@ struct coresight_device *coresight_get_sink_by_id(u32 id); > > struct list_head *coresight_build_path(struct coresight_device *csdev, > > struct coresight_device *sink); > > void coresight_release_path(struct list_head *path); > > +int coresight_add_sysfs_link(struct coresight_sysfs_link *info); > > +void coresight_remove_sysfs_link(struct coresight_sysfs_link *info); > > +int coresight_create_conns_sysfs_group(struct coresight_device *csdev); > > +void coresight_remove_conns_sysfs_group(struct coresight_device *csdev); > > > > #ifdef CONFIG_CORESIGHT_SOURCE_ETM3X > > extern int etm_readl_cp14(u32 off, unsigned int *val); > > diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c > > new file mode 100644 > > index 000000000000..17d565941e5e > > --- /dev/null > > +++ b/drivers/hwtracing/coresight/coresight-sysfs.c > > @@ -0,0 +1,124 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Copyright (c) 2019, Linaro Limited, All rights reserved. > > + * Author: Mike Leach <mike.leach@xxxxxxxxxx> > > + */ > > + > > +#include <linux/device.h> > > +#include <linux/kernel.h> > > + > > +#include "coresight-priv.h" > > + > > +/* > > + * Connections group - links attribute. > > + * Count of created links between coresight components in the group. > > + */ > > +static ssize_t nr_links_show(struct device *dev, > > + struct device_attribute *attr, > > + char *buf) > > +{ > > + struct coresight_device *csdev = to_coresight_device(dev); > > + > > + return scnprintf(buf, PAGE_SIZE, "%d\n", csdev->nr_links); > > +} > > +static DEVICE_ATTR_RO(nr_links); > > + > > +static struct attribute *coresight_conns_attrs[] = { > > + &dev_attr_nr_links.attr, > > + NULL, > > +}; > > + > > +static struct attribute_group coresight_conns_group = { > > + .attrs = coresight_conns_attrs, > > + .name = "connections", > > +}; > > + > > +/* > > + * Create connections group for CoreSight devices. > > + * This group will then be used to collate the sysfs links between > > + * devices. > > + */ > > +int coresight_create_conns_sysfs_group(struct coresight_device *csdev) > > +{ > > + int ret = 0; > > + > > + if (!csdev) > > + return -EINVAL; > > + > > + ret = sysfs_create_group(&csdev->dev.kobj, &coresight_conns_group); > > + if (ret) > > + return ret; > > + > > + csdev->has_conns_grp = true; > > The only place coresight_create_conns_sysfs_group() is used is in > coresight_register() where an error is returned to driver probe() functions if > an error occurs. Have you found places where csdev->has_conns_grp is needed? > If not please remove. > There is a sequence of calls in coresight_register() which occur after the coresight_create_conns_sysfs_group() - any one of which may throw an error resulting in an immediate coresight_unregister() and hence coresight_release_platform_data() => coresight_remove_conns_sysfs_group(). There is also an alternate path through coresight_register() which also results in coresight_release_platform_data() occurring before we have created the group. The flag ensures that both paths clean up the sysfs connection data correctly and safely. Regards Mike > > + return ret; > > +} > > + > > +void coresight_remove_conns_sysfs_group(struct coresight_device *csdev) > > +{ > > + if (!csdev) > > + return; > > + > > + if (csdev->has_conns_grp) { > > + sysfs_remove_group(&csdev->dev.kobj, &coresight_conns_group); > > + csdev->has_conns_grp = false; > > + } > > +} > > + > > +int coresight_add_sysfs_link(struct coresight_sysfs_link *info) > > +{ > > + int ret = 0; > > + > > + if (!info) > > + return -EINVAL; > > + if (!info->orig || !info->target || > > + !info->orig_name || !info->target_name) > > + return -EINVAL; > > + if (!info->orig->has_conns_grp || !info->target->has_conns_grp) > > + return -EINVAL; > > + > > + /* first link orig->target */ > > + ret = sysfs_add_link_to_group(&info->orig->dev.kobj, > > + coresight_conns_group.name, > > + &info->target->dev.kobj, > > + info->orig_name); > > + if (ret) > > + return ret; > > + > > + /* second link target->orig */ > > + ret = sysfs_add_link_to_group(&info->target->dev.kobj, > > + coresight_conns_group.name, > > + &info->orig->dev.kobj, > > + info->target_name); > > + > > + /* error in second link - remove first - otherwise inc counts */ > > + if (ret) { > > + sysfs_remove_link_from_group(&info->orig->dev.kobj, > > + coresight_conns_group.name, > > + info->orig_name); > > + } else { > > + info->orig->nr_links++; > > + info->target->nr_links++; > > + } > > + > > + return ret; > > +} > > + > > +void coresight_remove_sysfs_link(struct coresight_sysfs_link *info) > > +{ > > + if (!info) > > + return; > > + if (!info->orig || !info->target || > > + !info->orig_name || !info->target_name) > > + return; > > + > > + sysfs_remove_link_from_group(&info->orig->dev.kobj, > > + coresight_conns_group.name, > > + info->orig_name); > > + > > + sysfs_remove_link_from_group(&info->target->dev.kobj, > > + coresight_conns_group.name, > > + info->target_name); > > + > > + info->orig->nr_links--; > > + info->target->nr_links--; > > +} > > diff --git a/include/linux/coresight.h b/include/linux/coresight.h > > index 193cc9dbf448..a2ec25e02ca9 100644 > > --- a/include/linux/coresight.h > > +++ b/include/linux/coresight.h > > @@ -148,6 +148,20 @@ struct coresight_connection { > > struct coresight_device *child_dev; > > }; > > > > +/** > > + * struct coresight_sysfs_link - representation of a connection in sysfs. > > + * @orig: Originating (master) coresight device for the link. > > + * @orig_name: Name to use for the link orig->target. > > + * @target: Target (slave) coresight device for the link. > > + * @target_name: Name to use for the link target->orig. > > + */ > > +struct coresight_sysfs_link { > > + struct coresight_device *orig; > > + const char *orig_name; > > + struct coresight_device *target; > > + const char *target_name; > > +}; > > + > > /** > > * struct coresight_device - representation of a device as used by the framework > > * @pdata: Platform data with device connections associated to this device. > > @@ -165,6 +179,9 @@ struct coresight_connection { > > * @ea: Device attribute for sink representation under PMU directory. > > * @ect_dev: Associated cross trigger device. Not part of the trace data > > * path or connections. > > + * @nr_links: number of sysfs links created to other components from this > > + * device. These will appear in the "connections" group. > > + * @has_conns_grp: Have added a "connections" group for sysfs links. > > */ > > struct coresight_device { > > struct coresight_platform_data *pdata; > > @@ -180,6 +197,9 @@ struct coresight_device { > > struct dev_ext_attribute *ea; > > /* cross trigger handling */ > > struct coresight_device *ect_dev; > > + /* sysfs links between components */ > > + int nr_links; > > + bool has_conns_grp; > > }; > > With the above: > > Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> > > > > > /* > > -- > > 2.17.1 > > -- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK