On 10/04/15 01:28, Gabriel L. Somlo wrote: > From: Gabriel Somlo <somlo@xxxxxxx> > > Make fw_cfg entries of type "file" available via sysfs. Entries > are listed under /sys/firmware/qemu_fw_cfg/by_key, in folders > named after each entry's selector key. Filename, selector value, > and size read-only attributes are included for each entry. Also, > a "raw" attribute allows retrieval of the full binary content of > each entry. > > This patch also provides a documentation file outlining the > guest-side "hardware" interface exposed by the QEMU fw_cfg device. > > Signed-off-by: Gabriel Somlo <somlo@xxxxxxx> > --- > .../ABI/testing/sysfs-firmware-qemu_fw_cfg | 167 ++++++++ > drivers/firmware/Kconfig | 10 + > drivers/firmware/Makefile | 1 + > drivers/firmware/qemu_fw_cfg.c | 456 +++++++++++++++++++++ > 4 files changed, 634 insertions(+) > create mode 100644 Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg > create mode 100644 drivers/firmware/qemu_fw_cfg.c > > diff --git a/Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg b/Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg > new file mode 100644 > index 0000000..f1ef44e > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg > @@ -0,0 +1,167 @@ > +What: /sys/firmware/qemu_fw_cfg/ > +Date: August 2015 > +Contact: Gabriel Somlo <somlo@xxxxxxx> > +Description: > + Several different architectures supported by QEMU (x86, arm, > + sun4*, ppc/mac) are provisioned with a firmware configuration > + (fw_cfg) device, used by the host to provide configuration data > + to the starting guest. While most of this data is meant for use > + by the guest firmware, starting with QEMU v2.4, guest VMs may > + be given arbitrary fw_cfg entries supplied directly on the > + command line, which therefore may be of interest to userspace. > + > + === Guest-side Hardware Interface === > + > + The fw_cfg device is available to guest VMs as a register pair > + (control and data), accessible as either a IO ports or as MMIO > + addresses, depending on the architecture. > + > + --- Control Register --- > + > + Width: 16-bit > + Access: Write-Only > + Endianness: LE (if IOport) or BE (if MMIO) > + > + A write to the control register selects the index for one of > + the firmware configuration items (or "blobs") available on the > + fw_cfg device, which can subsequently be read from the data > + register. > + > + Each time the control register is written, an data offset > + internal to the fw_cfg device will be set to zero. This data > + offset impacts which portion of the selected fw_cfg blob is > + accessed by reading the data register, as explained below. > + > + --- Data Register --- > + > + Width: 8-bit (if IOport), or 8/16/32/64-bit (if MMIO) > + Access: Read-Only > + Endianness: string preserving > + > + The data register allows access to an array of bytes which > + represent the fw_cfg blob last selected by a write to the > + control register. > + > + Immediately following a write to the control register, the data > + offset will be set to zero. Each successful read access to the > + data register will increment the data offset by the appropriate > + access width. > + > + Each fw_cfg blob has a maximum associated data length. Once the > + data offset exceeds this maximum length, any subsequent reads > + via the data register will return 0x00. > + > + An N-byte wide read of the data register will return the next > + available N bytes of the selected fw_cfg blob, as a substring, > + in increasing address order, similar to memcpy(), zero-padded > + if necessary should the maximum data length of the selected > + item be reached, as described above. > + > + --- Per-arch Register Details --- > + > + ------------------------------------------------------------- > + arch access base ctrl ctrl data max. > + mode address offset endian offset data > + (bytes) (bytes) > + ------------------------------------------------------------- > + x86* IOport 0x510 0 LE 1 1 > + arm MMIO 0x9020000 8 BE 0 8 > + sun4u IOport 0x510 0 LE 1 1 > + sun4m MMIO 0xd00000510 0 BE 2 1 > + ppc/mac MMIO 0xf0000510 0 BE 2 1 > + ------------------------------------------------------------- > + > + NOTE 1. On platforms where the fw_cfg registers are exposed as > + IO ports, the data port number will always be one greater than > + the port number of the control register. I.e., the two ports > + are overlapping, and can not be mapped separately. > + > + === Firmware Configuration Items of Interest === > + > + Originally, the index key, size, and formatting of blobs in > + fw_cfg was hard coded by mutual agreement between QEMU on the > + host side, and the guest-side firmware. Later on, a file > + transfer interface was added: by reading a special blob, the > + fw_cfg consumer can retrieve a list of records containing the > + name, selector key, and size of further fw_cfg blobs made > + available by the host. Below we describe three fw_cfg blobs > + of interest to the sysfs driver. > + > + --- Signature (Key 0x0000, FW_CFG_SIGNATURE) --- > + > + The presence of the fw_cfg device can be verified by selecting > + the signature blob by writing 0x0000 to the control register, > + and reading four bytes from the data register. If the fw_cfg > + device is present, the four bytes read will match the ASCII > + characters "QEMU". > + > + --- Revision (Key 0x0001, FW_CFG_ID) --- > + > + A 32-bit little-endian unsigned integer, this item is used as > + an interface revision number. > + > + --- File Directory (Key 0x0019, FW_CFG_FILE_DIR) --- > + > + Any fw_cfg blobs stored at key 0x0020 FW_CFG_FILE_FIRST() or > + higher will have an associated entry in this "directory" blob, > + which facilitates the discovery of available items by software > + (e.g. BIOS) running on the guest. The format of the directory > + blob is shown below. > + > + NOTE: All integers are stored in big-endian format! > + > + /* the entire file directory "blob" */ > + struct FWCfgFiles { > + u32 count; /* total number of entries */ > + struct FWCfgFile f[]; /* entry array, see below */ > + }; > + > + /* an individual directory entry, 64 bytes total */ > + struct FWCfgFile { > + u32 size; /* size of referenced blob */ > + u16 select; /* selector key for referenced blob */ > + u16 reserved; > + char name[56]; /* blob name, nul-terminated ASCII */ > + }; I think the above is somewhat redundant with regard to "Documentation/devicetree/bindings/arm/fw-cfg.txt". That may not necessarily be a problem, I'd just like to make you aware of that file too. Perhaps that file should be updated too. ... In any case, I wanted to call your attention to that file, because it's been now raised that the driver should handle both ACPI and DT guests. In DT, the device is already exposed -- that's how the UEFI guest firmware for aarch64 guests learns about it. So, if you'd like to follow the example of "drivers/virtio/virtio_mmio.c" (which I think would be a good idea), in order to recognize the device in both DT and ACPI guests, then on the QEMU side, you won't have to do anything for DT, because "qemu,fw-cfg-mmio" is already exposed in create_fw_cfg() [hw/arm/virt.c]. Thanks Laszlo > + > + === SysFS fw_cfg Interface === > + > + The fw_cfg sysfs interface described in this document is only > + intended to display discoverable blobs (i.e., those registered > + with the file directory), as there is no way to determine the > + presence or size of "legacy" blobs (with selector keys between > + 0x0002 and 0x0018) programmatically. > + > + All fw_cfg information is shown under: > + > + /sys/firmware/qemu_fw_cfg/ > + > + The only legacy blob displayed is the fw_cfg device revision: > + > + /sys/firmware/qemu_fw_cfg/rev > + > + --- Discoverable fw_cfg blobs by selector key --- > + > + All discoverable blobs listed in the fw_cfg file directory are > + displayed as entries named after their unique selector key > + value, e.g.: > + > + /sys/firmware/qemu_fw_cfg/by_key/32 > + /sys/firmware/qemu_fw_cfg/by_key/33 > + /sys/firmware/qemu_fw_cfg/by_key/34 > + ... > + > + Each such fw_cfg sysfs entry has the following values exported > + as attributes: > + > + name : The 56-byte nul-terminated ASCII string used as the > + blob's 'file name' in the fw_cfg directory. > + size : The length of the blob, as given in the fw_cfg > + directory. > + key : The value of the blob's selector key as given in the > + fw_cfg directory. This value is the same as used in > + the parent directory name. > + raw : The raw bytes of the blob, obtained by selecting the > + entry via the control register, and reading a number > + of bytes equal to the blob size from the data > + register. > diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig > index 665efca..0466e80 100644 > --- a/drivers/firmware/Kconfig > +++ b/drivers/firmware/Kconfig > @@ -135,6 +135,16 @@ config ISCSI_IBFT > detect iSCSI boot parameters dynamically during system boot, say Y. > Otherwise, say N. > > +config FW_CFG_SYSFS > + tristate "QEMU fw_cfg device support in sysfs" > + depends on SYSFS > + default n > + help > + Say Y or M here to enable the exporting of the QEMU firmware > + configuration (fw_cfg) file entries via sysfs. Entries are > + found under /sys/firmware/fw_cfg when this option is enabled > + and loaded. > + > config QCOM_SCM > bool > depends on ARM || ARM64 > diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile > index 2ee8347..efba22a 100644 > --- a/drivers/firmware/Makefile > +++ b/drivers/firmware/Makefile > @@ -12,6 +12,7 @@ obj-$(CONFIG_DMIID) += dmi-id.o > obj-$(CONFIG_ISCSI_IBFT_FIND) += iscsi_ibft_find.o > obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o > obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o > +obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o > obj-$(CONFIG_QCOM_SCM) += qcom_scm.o > obj-$(CONFIG_QCOM_SCM_64) += qcom_scm-64.o > obj-$(CONFIG_QCOM_SCM_32) += qcom_scm-32.o > diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c > new file mode 100644 > index 0000000..3a67a16 > --- /dev/null > +++ b/drivers/firmware/qemu_fw_cfg.c > @@ -0,0 +1,456 @@ > +/* > + * drivers/firmware/qemu_fw_cfg.c > + * > + * Expose entries from QEMU's firmware configuration (fw_cfg) device in > + * sysfs (read-only, under "/sys/firmware/qemu_fw_cfg/..."). > + * > + * Copyright 2015 Carnegie Mellon University > + */ > + > +#include <linux/module.h> > +#include <linux/slab.h> > +#include <linux/io.h> > +#include <linux/ioport.h> > + > +MODULE_AUTHOR("Gabriel L. Somlo <somlo@xxxxxxx>"); > +MODULE_DESCRIPTION("QEMU fw_cfg sysfs support"); > +MODULE_LICENSE("GPL"); > + > +/* selector key values for "well-known" fw_cfg entries */ > +#define FW_CFG_SIGNATURE 0x00 > +#define FW_CFG_ID 0x01 > +#define FW_CFG_FILE_DIR 0x19 > + > +/* size in bytes of fw_cfg signature */ > +#define FW_CFG_SIG_SIZE 4 > + > +/* fw_cfg "file name" is up to 56 characters (including terminating nul) */ > +#define FW_CFG_MAX_FILE_PATH 56 > + > +/* fw_cfg file directory entry type */ > +struct fw_cfg_file { > + u32 size; > + u16 select; > + u16 reserved; > + char name[FW_CFG_MAX_FILE_PATH]; > +}; > + > +/* fw_cfg device i/o access options type */ > +struct fw_cfg_access { > + const char *name; > + phys_addr_t base; > + u8 size; > + u8 ctrl_offset; > + u8 data_offset; > + bool is_mmio; > +}; > + > +/* table of fw_cfg device i/o access options for known architectures */ > +static struct fw_cfg_access fw_cfg_modes[] = { > + { > + .name = "fw_cfg IOport on i386, sun4u", > + .base = 0x510, > + .size = 0x02, > + .ctrl_offset = 0x00, > + .data_offset = 0x01, > + .is_mmio = false, > + }, { > + .name = "fw_cfg MMIO on arm", > + .base = 0x9020000, > + .size = 0x0a, > + .ctrl_offset = 0x08, > + .data_offset = 0x00, > + .is_mmio = true, > + }, { > + .name = "fw_cfg MMIO on sun4m", > + .base = 0xd00000510, > + .size = 0x03, > + .ctrl_offset = 0x00, > + .data_offset = 0x02, > + .is_mmio = true, > + }, { > + .name = "fw_cfg MMIO on ppc/mac", > + .base = 0xf0000510, > + .size = 0x03, > + .ctrl_offset = 0x00, > + .data_offset = 0x02, > + .is_mmio = true, > + }, { } /* END */ > +}; > + > +/* fw_cfg device i/o currently selected option set */ > +static struct fw_cfg_access *fw_cfg_mode; > + > +/* fw_cfg device i/o register addresses */ > +static void __iomem *fw_cfg_dev_base; > +static void __iomem *fw_cfg_reg_ctrl; > +static void __iomem *fw_cfg_reg_data; > + > +/* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */ > +static DEFINE_MUTEX(fw_cfg_dev_lock); > + > +/* pick appropriate endianness for selector key */ > +static inline u16 fw_cfg_sel_endianness(u16 key) > +{ > + return fw_cfg_mode->is_mmio ? cpu_to_be16(key) : cpu_to_le16(key); > +} > + > +/* type for fw_cfg "directory scan" visitor/callback function */ > +typedef int (*fw_cfg_file_callback)(const struct fw_cfg_file *f); > + > +/* run a given callback on each fw_cfg directory entry */ > +static int fw_cfg_scan_dir(fw_cfg_file_callback callback) > +{ > + int ret = 0; > + u32 count, i; > + struct fw_cfg_file f; > + > + mutex_lock(&fw_cfg_dev_lock); > + iowrite16(fw_cfg_sel_endianness(FW_CFG_FILE_DIR), fw_cfg_reg_ctrl); > + ioread8_rep(fw_cfg_reg_data, &count, sizeof(count)); > + for (i = 0; i < be32_to_cpu(count); i++) { > + ioread8_rep(fw_cfg_reg_data, &f, sizeof(f)); > + ret = callback(&f); > + if (ret) > + break; > + } > + mutex_unlock(&fw_cfg_dev_lock); > + return ret; > +} > + > +/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */ > +static inline void fw_cfg_read_blob(u16 key, > + void *buf, loff_t pos, size_t count) > +{ > + mutex_lock(&fw_cfg_dev_lock); > + iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl); > + while (pos-- > 0) > + ioread8(fw_cfg_reg_data); > + ioread8_rep(fw_cfg_reg_data, buf, count); > + mutex_unlock(&fw_cfg_dev_lock); > +} > + > +/* clean up fw_cfg device i/o */ > +static void fw_cfg_io_cleanup(void) > +{ > + if (fw_cfg_mode->is_mmio) { > + iounmap(fw_cfg_dev_base); > + release_mem_region(fw_cfg_mode->base, fw_cfg_mode->size); > + } else { > + ioport_unmap(fw_cfg_dev_base); > + release_region(fw_cfg_mode->base, fw_cfg_mode->size); > + } > +} > + > +/* probe and map fw_cfg device */ > +static int __init fw_cfg_io_probe(void) > +{ > + char sig[FW_CFG_SIG_SIZE]; > + > + for (fw_cfg_mode = &fw_cfg_modes[0]; > + fw_cfg_mode->base; fw_cfg_mode++) { > + > + phys_addr_t base = fw_cfg_mode->base; > + u8 size = fw_cfg_mode->size; > + > + /* reserve and map mmio or ioport region */ > + if (fw_cfg_mode->is_mmio) { > + if (!request_mem_region(base, size, fw_cfg_mode->name)) > + continue; > + fw_cfg_dev_base = ioremap(base, size); > + if (!fw_cfg_dev_base) { > + release_mem_region(base, size); > + continue; > + } > + } else { > + if (!request_region(base, size, fw_cfg_mode->name)) > + continue; > + fw_cfg_dev_base = ioport_map(base, size); > + if (!fw_cfg_dev_base) { > + release_region(base, size); > + continue; > + } > + } > + > + /* set control and data register addresses */ > + fw_cfg_reg_ctrl = fw_cfg_dev_base + fw_cfg_mode->ctrl_offset; > + fw_cfg_reg_data = fw_cfg_dev_base + fw_cfg_mode->data_offset; > + > + /* verify fw_cfg device signature */ > + fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE); > + if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) == 0) > + /* success, we're done */ > + return 0; > + > + /* clean up before probing next access mode */ > + fw_cfg_io_cleanup(); > + } > + > + return -ENODEV; > +} > + > +/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */ > +static u32 fw_cfg_rev; > + > +static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf) > +{ > + return sprintf(buf, "%u\n", fw_cfg_rev); > +} > + > +static const struct { > + struct attribute attr; > + ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf); > +} fw_cfg_rev_attr = { > + .attr = { .name = "rev", .mode = S_IRUSR }, > + .show = fw_cfg_showrev, > +}; > + > +/* fw_cfg_sysfs_entry type */ > +struct fw_cfg_sysfs_entry { > + struct kobject kobj; > + struct fw_cfg_file f; > + struct list_head list; > +}; > + > +/* get fw_cfg_sysfs_entry from kobject member */ > +static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj) > +{ > + return container_of(kobj, struct fw_cfg_sysfs_entry, kobj); > +} > + > +/* fw_cfg_sysfs_attribute type */ > +struct fw_cfg_sysfs_attribute { > + struct attribute attr; > + ssize_t (*show)(struct fw_cfg_sysfs_entry *entry, char *buf); > +}; > + > +/* get fw_cfg_sysfs_attribute from attribute member */ > +static inline struct fw_cfg_sysfs_attribute *to_attr(struct attribute *attr) > +{ > + return container_of(attr, struct fw_cfg_sysfs_attribute, attr); > +} > + > +/* global cache of fw_cfg_sysfs_entry objects */ > +static LIST_HEAD(fw_cfg_entry_cache); > + > +/* kobjects removed lazily by kernel, mutual exclusion needed */ > +static DEFINE_SPINLOCK(fw_cfg_cache_lock); > + > +static inline void fw_cfg_sysfs_cache_enlist(struct fw_cfg_sysfs_entry *entry) > +{ > + spin_lock(&fw_cfg_cache_lock); > + list_add_tail(&entry->list, &fw_cfg_entry_cache); > + spin_unlock(&fw_cfg_cache_lock); > +} > + > +static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry) > +{ > + spin_lock(&fw_cfg_cache_lock); > + list_del(&entry->list); > + spin_unlock(&fw_cfg_cache_lock); > +} > + > +static void fw_cfg_sysfs_cache_cleanup(void) > +{ > + struct fw_cfg_sysfs_entry *entry, *next; > + > + list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) { > + /* will end up invoking fw_cfg_sysfs_cache_delist() > + * via each object's release() method (i.e. destructor) > + */ > + kobject_put(&entry->kobj); > + } > +} > + > +/* default_attrs: per-entry attributes and show methods */ > + > +#define FW_CFG_SYSFS_ATTR(_attr) \ > +struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \ > + .attr = { .name = __stringify(_attr), .mode = S_IRUSR }, \ > + .show = fw_cfg_sysfs_show_##_attr, \ > +} > + > +static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf) > +{ > + return sprintf(buf, "%u\n", e->f.size); > +} > + > +static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf) > +{ > + return sprintf(buf, "%u\n", e->f.select); > +} > + > +static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf) > +{ > + return sprintf(buf, "%s\n", e->f.name); > +} > + > +static FW_CFG_SYSFS_ATTR(size); > +static FW_CFG_SYSFS_ATTR(key); > +static FW_CFG_SYSFS_ATTR(name); > + > +static struct attribute *fw_cfg_sysfs_entry_attrs[] = { > + &fw_cfg_sysfs_attr_size.attr, > + &fw_cfg_sysfs_attr_key.attr, > + &fw_cfg_sysfs_attr_name.attr, > + NULL, > +}; > + > +/* sysfs_ops: find fw_cfg_[entry, attribute] and call appropriate show method */ > +static ssize_t fw_cfg_sysfs_attr_show(struct kobject *kobj, struct attribute *a, > + char *buf) > +{ > + struct fw_cfg_sysfs_entry *entry = to_entry(kobj); > + struct fw_cfg_sysfs_attribute *attr = to_attr(a); > + > + return attr->show(entry, buf); > +} > + > +static const struct sysfs_ops fw_cfg_sysfs_attr_ops = { > + .show = fw_cfg_sysfs_attr_show, > +}; > + > +/* release: destructor, to be called via kobject_put() */ > +static void fw_cfg_sysfs_release_entry(struct kobject *kobj) > +{ > + struct fw_cfg_sysfs_entry *entry = to_entry(kobj); > + > + fw_cfg_sysfs_cache_delist(entry); > + kfree(entry); > +} > + > +/* kobj_type: ties together all properties required to register an entry */ > +static struct kobj_type fw_cfg_sysfs_entry_ktype = { > + .default_attrs = fw_cfg_sysfs_entry_attrs, > + .sysfs_ops = &fw_cfg_sysfs_attr_ops, > + .release = fw_cfg_sysfs_release_entry, > +}; > + > +/* raw-read method and attribute */ > +static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj, > + struct bin_attribute *bin_attr, > + char *buf, loff_t pos, size_t count) > +{ > + struct fw_cfg_sysfs_entry *entry = to_entry(kobj); > + > + if (pos > entry->f.size) > + return -EINVAL; > + > + if (count > entry->f.size - pos) > + count = entry->f.size - pos; > + > + fw_cfg_read_blob(entry->f.select, buf, pos, count); > + return count; > +} > + > +static struct bin_attribute fw_cfg_sysfs_attr_raw = { > + .attr = { .name = "raw", .mode = 0400 }, > + .read = fw_cfg_sysfs_read_raw, > +}; > + > +/* kobjects & kset representing top-level, by_key, and by_name folders */ > +static struct kobject *fw_cfg_top_ko; > +static struct kobject *fw_cfg_sel_ko; > + > +/* callback function to register an individual fw_cfg file */ > +static int __init fw_cfg_register_file(const struct fw_cfg_file *f) > +{ > + int err; > + struct fw_cfg_sysfs_entry *entry; > + > + /* allocate new entry */ > + entry = kzalloc(sizeof(*entry), GFP_KERNEL); > + if (!entry) > + return -ENOMEM; > + > + /* set file entry information */ > + entry->f.size = be32_to_cpu(f->size); > + entry->f.select = be16_to_cpu(f->select); > + strcpy(entry->f.name, f->name); > + > + /* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */ > + err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype, > + fw_cfg_sel_ko, "%d", entry->f.select); > + if (err) > + goto err_register; > + > + /* add raw binary content access */ > + err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw); > + if (err) > + goto err_add_raw; > + > + /* success, add entry to global cache */ > + fw_cfg_sysfs_cache_enlist(entry); > + return 0; > + > +err_add_raw: > + kobject_del(&entry->kobj); > +err_register: > + kfree(entry); > + return err; > +} > + > +/* unregister top-level or by_key folder */ > +static inline void fw_cfg_kobj_cleanup(struct kobject *kobj) > +{ > + kobject_del(kobj); > + kobject_put(kobj); > +} > + > +static int __init fw_cfg_sysfs_init(void) > +{ > + int err; > + > + /* probe for the fw_cfg "hardware" */ > + err = fw_cfg_io_probe(); > + if (err) > + return err; > + > + /* create /sys/firmware/qemu_fw_cfg/ and its subdirectories */ > + err = -ENOMEM; > + fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj); > + if (!fw_cfg_top_ko) > + goto err_top; > + fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko); > + if (!fw_cfg_sel_ko) > + goto err_sel; > + > + /* get revision number, add matching top-level attribute */ > + fw_cfg_read_blob(FW_CFG_ID, &fw_cfg_rev, 0, sizeof(fw_cfg_rev)); > + fw_cfg_rev = le32_to_cpu(fw_cfg_rev); > + err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); > + if (err) > + goto err_rev; > + > + /* process fw_cfg file directory entry, registering each file */ > + err = fw_cfg_scan_dir(fw_cfg_register_file); > + if (err) > + goto err_scan; > + > + /* success */ > + pr_debug("fw_cfg: loaded.\n"); > + return 0; > + > +err_scan: > + fw_cfg_sysfs_cache_cleanup(); > + sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); > +err_rev: > + fw_cfg_kobj_cleanup(fw_cfg_sel_ko); > +err_sel: > + fw_cfg_kobj_cleanup(fw_cfg_top_ko); > +err_top: > + fw_cfg_io_cleanup(); > + return err; > +} > + > +static void __exit fw_cfg_sysfs_exit(void) > +{ > + pr_debug("fw_cfg: unloading.\n"); > + fw_cfg_sysfs_cache_cleanup(); > + fw_cfg_kobj_cleanup(fw_cfg_sel_ko); > + fw_cfg_kobj_cleanup(fw_cfg_top_ko); > + fw_cfg_io_cleanup(); > +} > + > +module_init(fw_cfg_sysfs_init); > +module_exit(fw_cfg_sysfs_exit); > -- 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