lkml.org 
[lkml]   [2016]   [Jan]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v8 1/4] firmware: introduce sysfs driver for QEMU's fw_cfg device
    Date
    From: Gabriel Somlo <somlo@cmu.edu>

    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.

    The fw_cfg device can be instantiated automatically from ACPI or
    the Device Tree, or manually by using a kernel module (or command
    line) parameter, with a syntax outlined in the documentation file.

    Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
    ---
    .../ABI/testing/sysfs-firmware-qemu_fw_cfg | 58 ++
    drivers/firmware/Kconfig | 19 +
    drivers/firmware/Makefile | 1 +
    drivers/firmware/qemu_fw_cfg.c | 648 +++++++++++++++++++++
    4 files changed, 726 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..e9e58d4
    --- /dev/null
    +++ b/Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg
    @@ -0,0 +1,58 @@
    +What: /sys/firmware/qemu_fw_cfg/
    +Date: August 2015
    +Contact: Gabriel Somlo <somlo@cmu.edu>
    +Description:
    + Several different architectures supported by QEMU (x86, arm,
    + sun4*, ppc/mac) are provisioned with a firmware configuration
    + (fw_cfg) device, originally intended as a way for the host to
    + provide configuration data to the guest firmware. Starting
    + with QEMU v2.4, arbitrary fw_cfg file entries may be specified
    + by the user on the command line, which makes fw_cfg additionally
    + useful as an out-of-band, asynchronous mechanism for providing
    + configuration data to the guest userspace.
    +
    + The authoritative guest-side hardware interface documentation
    + to the fw_cfg device can be found in "docs/specs/fw_cfg.txt"
    + in the QEMU source tree.
    +
    + === 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 49a3a11..5130f74 100644
    --- a/drivers/firmware/Kconfig
    +++ b/drivers/firmware/Kconfig
    @@ -161,6 +161,25 @@ config RASPBERRYPI_FIRMWARE
    This option enables support for communicating with the firmware on the
    Raspberry Pi.

    +config FW_CFG_SYSFS
    + tristate "QEMU fw_cfg device support in sysfs"
    + depends on SYSFS && (ARM || ARM64 || PPC_PMAC || SPARC || X86)
    + 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 FW_CFG_SYSFS_CMDLINE
    + bool "QEMU fw_cfg device parameter parsing"
    + depends on FW_CFG_SYSFS
    + help
    + Allow the qemu_fw_cfg device to be initialized via the kernel
    + command line or using a module parameter.
    + WARNING: Using incorrect parameters (base address in particular)
    + may crash your system.
    +
    config QCOM_SCM
    bool
    depends on ARM || ARM64
    diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
    index 48dd417..474bada 100644
    --- a/drivers/firmware/Makefile
    +++ b/drivers/firmware/Makefile
    @@ -14,6 +14,7 @@ obj-$(CONFIG_ISCSI_IBFT_FIND) += iscsi_ibft_find.o
    obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o
    obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o
    obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.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..83e8a5c
    --- /dev/null
    +++ b/drivers/firmware/qemu_fw_cfg.c
    @@ -0,0 +1,648 @@
    +/*
    + * drivers/firmware/qemu_fw_cfg.c
    + *
    + * Copyright 2015 Carnegie Mellon University
    + *
    + * Expose entries from QEMU's firmware configuration (fw_cfg) device in
    + * sysfs (read-only, under "/sys/firmware/qemu_fw_cfg/...").
    + *
    + * The fw_cfg device may be instantiated via either an ACPI node (on x86
    + * and select subsets of aarch64), a Device Tree node (on arm), or using
    + * a kernel module (or command line) parameter with the following syntax:
    + *
    + * [fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>]
    + * or
    + * [fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>]
    + *
    + * where:
    + * <size> := size of ioport or mmio range
    + * <base> := physical base address of ioport or mmio range
    + * <ctrl_off> := (optional) offset of control register
    + * <data_off> := (optional) offset of data register
    + *
    + * e.g.:
    + * fw_cfg.ioport=2@0x510:0:1 (the default on x86)
    + * or
    + * fw_cfg.mmio=0xA@0x9020000:8:0 (the default on arm)
    + */
    +
    +#include <linux/module.h>
    +#include <linux/platform_device.h>
    +#include <linux/acpi.h>
    +#include <linux/slab.h>
    +#include <linux/io.h>
    +#include <linux/ioport.h>
    +
    +MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>");
    +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 register addresses */
    +static bool fw_cfg_is_mmio;
    +static phys_addr_t fw_cfg_p_base;
    +static resource_size_t fw_cfg_p_size;
    +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_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
    +}
    +
    +/* 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_is_mmio) {
    + iounmap(fw_cfg_dev_base);
    + release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
    + } else {
    + ioport_unmap(fw_cfg_dev_base);
    + release_region(fw_cfg_p_base, fw_cfg_p_size);
    + }
    +}
    +
    +/* arch-specific ctrl & data register offsets are not available in ACPI, DT */
    +#if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CTRL_DATA_OFF))
    +# if (defined(CONFIG_ARM) || defined(CONFIG_ARM64))
    +# define FW_CFG_CTRL_OFF 0x08
    +# define FW_CFG_DATA_OFF 0x00
    +# elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */
    +# define FW_CFG_CTRL_OFF 0x00
    +# define FW_CFG_DATA_OFF 0x02
    +# elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */
    +# define FW_CFG_CTRL_OFF 0x00
    +# define FW_CFG_DATA_OFF 0x01
    +# else
    +# warning "QEMU FW_CFG may not be available on this architecture!"
    +# define FW_CFG_CTRL_OFF 0x00
    +# define FW_CFG_DATA_OFF 0x01
    +# endif
    +#endif
    +
    +/* initialize fw_cfg device i/o from platform data */
    +static int fw_cfg_do_platform_probe(struct platform_device *pdev)
    +{
    + char sig[FW_CFG_SIG_SIZE];
    + struct resource *range, *ctrl, *data;
    +
    + /* acquire i/o range details */
    + fw_cfg_is_mmio = false;
    + range = platform_get_resource(pdev, IORESOURCE_IO, 0);
    + if (!range) {
    + fw_cfg_is_mmio = true;
    + range = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    + if (!range)
    + return -EINVAL;
    + }
    + fw_cfg_p_base = range->start;
    + fw_cfg_p_size = resource_size(range);
    +
    + if (fw_cfg_is_mmio) {
    + if (!request_mem_region(fw_cfg_p_base,
    + fw_cfg_p_size, "fw_cfg_mem"))
    + return -EBUSY;
    + fw_cfg_dev_base = ioremap(fw_cfg_p_base, fw_cfg_p_size);
    + if (!fw_cfg_dev_base) {
    + release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
    + return -EFAULT;
    + }
    + } else {
    + if (!request_region(fw_cfg_p_base,
    + fw_cfg_p_size, "fw_cfg_io"))
    + return -EBUSY;
    + fw_cfg_dev_base = ioport_map(fw_cfg_p_base, fw_cfg_p_size);
    + if (!fw_cfg_dev_base) {
    + release_region(fw_cfg_p_base, fw_cfg_p_size);
    + return -EFAULT;
    + }
    + }
    +
    + /* were custom register offsets provided (e.g. on the command line)? */
    + ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl");
    + data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data");
    + if (ctrl && data) {
    + fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start;
    + fw_cfg_reg_data = fw_cfg_dev_base + data->start;
    + } else {
    + /* use architecture-specific offsets */
    + fw_cfg_reg_ctrl = fw_cfg_dev_base + FW_CFG_CTRL_OFF;
    + fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF;
    + }
    +
    + /* 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) {
    + fw_cfg_io_cleanup();
    + return -ENODEV;
    + }
    +
    + return 0;
    +}
    +
    +/* 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 = S_IRUSR },
    + .read = fw_cfg_sysfs_read_raw,
    +};
    +
    +/* kobjects representing top-level and by_key folders */
    +static struct kobject *fw_cfg_top_ko;
    +static struct kobject *fw_cfg_sel_ko;
    +
    +/* register an individual fw_cfg file */
    +static int 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 */
    + memcpy(&entry->f, f, sizeof(struct fw_cfg_file));
    +
    + /* 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;
    +}
    +
    +/* iterate over all fw_cfg directory entries, registering each one */
    +static int fw_cfg_register_dir_entries(void)
    +{
    + int ret = 0;
    + u32 count, i;
    + struct fw_cfg_file *dir;
    + size_t dir_size;
    +
    + fw_cfg_read_blob(FW_CFG_FILE_DIR, &count, 0, sizeof(count));
    + count = be32_to_cpu(count);
    + dir_size = count * sizeof(struct fw_cfg_file);
    +
    + dir = kmalloc(dir_size, GFP_KERNEL);
    + if (!dir)
    + return -ENOMEM;
    +
    + fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(count), dir_size);
    +
    + for (i = 0; i < count; i++) {
    + dir[i].size = be32_to_cpu(dir[i].size);
    + dir[i].select = be16_to_cpu(dir[i].select);
    + ret = fw_cfg_register_file(&dir[i]);
    + if (ret)
    + break;
    + }
    +
    + kfree(dir);
    + return ret;
    +}
    +
    +/* 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 fw_cfg_sysfs_probe(struct platform_device *pdev)
    +{
    + int err;
    +
    + /* NOTE: If we supported multiple fw_cfg devices, we'd first create
    + * a subdirectory named after e.g. pdev->id, then hang per-device
    + * by_key subdirectories underneath it. However, only
    + * one fw_cfg device exist system-wide, so if one was already found
    + * earlier, we might as well stop here.
    + */
    + if (fw_cfg_sel_ko)
    + return -EBUSY;
    +
    + /* create by_key subdirectory of /sys/firmware/qemu_fw_cfg/ */
    + err = -ENOMEM;
    + fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko);
    + if (!fw_cfg_sel_ko)
    + goto err_sel;
    +
    + /* initialize fw_cfg device i/o from platform data */
    + err = fw_cfg_do_platform_probe(pdev);
    + if (err)
    + goto err_probe;
    +
    + /* 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_register_dir_entries();
    + if (err)
    + goto err_dir;
    +
    + /* success */
    + pr_debug("fw_cfg: loaded.\n");
    + return 0;
    +
    +err_dir:
    + fw_cfg_sysfs_cache_cleanup();
    + sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
    +err_rev:
    + fw_cfg_io_cleanup();
    +err_probe:
    + fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
    +err_sel:
    + return err;
    +}
    +
    +static int fw_cfg_sysfs_remove(struct platform_device *pdev)
    +{
    + pr_debug("fw_cfg: unloading.\n");
    + fw_cfg_sysfs_cache_cleanup();
    + fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
    + fw_cfg_io_cleanup();
    + return 0;
    +}
    +
    +static const struct of_device_id fw_cfg_sysfs_mmio_match[] = {
    + { .compatible = "qemu,fw-cfg-mmio", },
    + {},
    +};
    +MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match);
    +
    +#ifdef CONFIG_ACPI
    +static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = {
    + { "QEMU0002", },
    + {},
    +};
    +MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
    +#endif
    +
    +static struct platform_driver fw_cfg_sysfs_driver = {
    + .probe = fw_cfg_sysfs_probe,
    + .remove = fw_cfg_sysfs_remove,
    + .driver = {
    + .name = "fw_cfg",
    + .of_match_table = fw_cfg_sysfs_mmio_match,
    + .acpi_match_table = ACPI_PTR(fw_cfg_sysfs_acpi_match),
    + },
    +};
    +
    +#ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
    +
    +static struct platform_device *fw_cfg_cmdline_dev;
    +
    +/* this probably belongs in e.g. include/linux/types.h,
    + * but right now we are the only ones doing it...
    + */
    +#ifdef CONFIG_PHYS_ADDR_T_64BIT
    +#define __PHYS_ADDR_PREFIX "ll"
    +#else
    +#define __PHYS_ADDR_PREFIX ""
    +#endif
    +
    +/* use special scanf/printf modifier for phys_addr_t, resource_size_t */
    +#define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \
    + ":%" __PHYS_ADDR_PREFIX "i" \
    + ":%" __PHYS_ADDR_PREFIX "i%n"
    +
    +#define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \
    + "0x%" __PHYS_ADDR_PREFIX "x"
    +
    +#define PH_ADDR_PR_3_FMT PH_ADDR_PR_1_FMT \
    + ":%" __PHYS_ADDR_PREFIX "u" \
    + ":%" __PHYS_ADDR_PREFIX "u"
    +
    +static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
    +{
    + struct resource res[3] = {};
    + char *str;
    + phys_addr_t base;
    + resource_size_t size, ctrl_off, data_off;
    + int processed, consumed = 0;
    +
    + /* only one fw_cfg device can exist system-wide, so if one
    + * was processed on the command line already, we might as
    + * well stop here.
    + */
    + if (fw_cfg_cmdline_dev) {
    + /* avoid leaking previously registered device */
    + platform_device_unregister(fw_cfg_cmdline_dev);
    + return -EINVAL;
    + }
    +
    + /* consume "<size>" portion of command line argument */
    + size = memparse(arg, &str);
    +
    + /* get "@<base>[:<ctrl_off>:<data_off>]" chunks */
    + processed = sscanf(str, PH_ADDR_SCAN_FMT,
    + &base, &consumed,
    + &ctrl_off, &data_off, &consumed);
    +
    + /* sscanf() must process precisely 1 or 3 chunks:
    + * <base> is mandatory, optionally followed by <ctrl_off>
    + * and <data_off>;
    + * there must be no extra characters after the last chunk,
    + * so str[consumed] must be '\0'.
    + */
    + if (str[consumed] ||
    + (processed != 1 && processed != 3))
    + return -EINVAL;
    +
    + res[0].start = base;
    + res[0].end = base + size - 1;
    + res[0].flags = !strcmp(kp->name, "mmio") ? IORESOURCE_MEM :
    + IORESOURCE_IO;
    +
    + /* insert register offsets, if provided */
    + if (processed > 1) {
    + res[1].name = "ctrl";
    + res[1].start = ctrl_off;
    + res[1].flags = IORESOURCE_REG;
    + res[2].name = "data";
    + res[2].start = data_off;
    + res[2].flags = IORESOURCE_REG;
    + }
    +
    + /* "processed" happens to nicely match the number of resources
    + * we need to pass in to this platform device.
    + */
    + fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg",
    + PLATFORM_DEVID_NONE, res, processed);
    + if (IS_ERR(fw_cfg_cmdline_dev))
    + return PTR_ERR(fw_cfg_cmdline_dev);
    +
    + return 0;
    +}
    +
    +static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp)
    +{
    + /* stay silent if device was not configured via the command
    + * line, or if the parameter name (ioport/mmio) doesn't match
    + * the device setting
    + */
    + if (!fw_cfg_cmdline_dev ||
    + (!strcmp(kp->name, "mmio") ^
    + (fw_cfg_cmdline_dev->resource[0].flags == IORESOURCE_MEM)))
    + return 0;
    +
    + switch (fw_cfg_cmdline_dev->num_resources) {
    + case 1:
    + return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_1_FMT,
    + resource_size(&fw_cfg_cmdline_dev->resource[0]),
    + fw_cfg_cmdline_dev->resource[0].start);
    + case 3:
    + return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_3_FMT,
    + resource_size(&fw_cfg_cmdline_dev->resource[0]),
    + fw_cfg_cmdline_dev->resource[0].start,
    + fw_cfg_cmdline_dev->resource[1].start,
    + fw_cfg_cmdline_dev->resource[2].start);
    + }
    +
    + /* Should never get here */
    + WARN(1, "Unexpected number of resources: %d\n",
    + fw_cfg_cmdline_dev->num_resources);
    + return 0;
    +}
    +
    +static const struct kernel_param_ops fw_cfg_cmdline_param_ops = {
    + .set = fw_cfg_cmdline_set,
    + .get = fw_cfg_cmdline_get,
    +};
    +
    +device_param_cb(ioport, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
    +device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
    +
    +#endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */
    +
    +static int __init fw_cfg_sysfs_init(void)
    +{
    + /* create /sys/firmware/qemu_fw_cfg/ top level directory */
    + fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj);
    + if (!fw_cfg_top_ko)
    + return -ENOMEM;
    +
    + return platform_driver_register(&fw_cfg_sysfs_driver);
    +}
    +
    +static void __exit fw_cfg_sysfs_exit(void)
    +{
    + platform_driver_unregister(&fw_cfg_sysfs_driver);
    +
    +#ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
    + platform_device_unregister(fw_cfg_cmdline_dev);
    +#endif
    +
    + /* clean up /sys/firmware/qemu_fw_cfg/ */
    + fw_cfg_kobj_cleanup(fw_cfg_top_ko);
    +}
    +
    +module_init(fw_cfg_sysfs_init);
    +module_exit(fw_cfg_sysfs_exit);
    --
    2.4.3
    \
     
     \ /
      Last update: 2016-01-28 15:41    [W:4.369 / U:0.140 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site