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. This patch also provides a documentation file outlining the guest-side "hardware" interface exposed by the QEMU fw_cfg device. 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 | 198 +++++++ drivers/firmware/Kconfig | 19 + drivers/firmware/Makefile | 1 + drivers/firmware/qemu_fw_cfg.c | 611 +++++++++++++++++++++ 4 files changed, 829 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..b908b6d --- /dev/null +++ b/Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg @@ -0,0 +1,198 @@ +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. + + === 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. + + NOTE 2. QEMU publishes the base and size of the register set + in ACPI (as _HID "QEMU0002", on x86 and select aarch64 subsets) + and in the Device Tree (as compatible = "qemu,fw-cfg-mmio", on + arm guests). + + NOTE 3. On architectures where automatic detection of fw_cfg + "hardware" (via ACPI or DT) is not supported, the guest side + kernel driver allows configuration using a 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 + and, optionally: + <ctrl_off> : offset of control register + <data_off> : offset of data register + + Since neither ACPI nor DT provide specific details on register + offsets within the overall specified register set range, using + <ctrl_off> and <data_off> allows the arm-specific default MMIO + offset values (8 and 0, respectively) to be overridden for e.g. + sun4m and ppc/mac, where the ofsets should be 0 and 2, + respectively. Using ppc/mac as an example: + + fw_cfg.mmio=3@0xf0000510:0:2 + + === 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 */ + }; + + === 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 cf478fe..3cf920a 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 + 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..618304a --- /dev/null +++ b/drivers/firmware/qemu_fw_cfg.c @@ -0,0 +1,611 @@ +/* + * 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); + } +} + +/* 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; + } + /* set register addresses (using arm/mmio offsets) */ + fw_cfg_reg_ctrl = fw_cfg_dev_base + 0x08; + fw_cfg_reg_data = fw_cfg_dev_base + 0x00; + } 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; + } + /* set register addresses (using pc/i386/ioport offsets) */ + fw_cfg_reg_ctrl = fw_cfg_dev_base + 0x00; + fw_cfg_reg_data = fw_cfg_dev_base + 0x01; + } + + /* 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; + } + + /* 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; + +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, "@%lli%n:%lli:%lli%n", + &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, "0x%llx@0x%llx", + resource_size(&fw_cfg_cmdline_dev->resource[0]), + fw_cfg_cmdline_dev->resource[0].start); + case 3: + return snprintf(buf, PAGE_SIZE, "0x%llx@0x%llx:%llu:%llu", + 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