diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/firmware/qemu_fw_cfg.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/firmware/qemu_fw_cfg.c')
-rw-r--r-- | drivers/firmware/qemu_fw_cfg.c | 940 |
1 files changed, 940 insertions, 0 deletions
diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c new file mode 100644 index 0000000000..a69399a6b7 --- /dev/null +++ b/drivers/firmware/qemu_fw_cfg.c @@ -0,0 +1,940 @@ +/* + * 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: + * + * [qemu_fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]] + * or + * [qemu_fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_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 + * <dma_off> := (optional) offset of dma register + * + * e.g.: + * qemu_fw_cfg.ioport=12@0x510:0:1:4 (the default on x86) + * or + * qemu_fw_cfg.mmio=16@0x9020000:8:0:16 (the default on arm) + */ + +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/acpi.h> +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <uapi/linux/qemu_fw_cfg.h> +#include <linux/delay.h> +#include <linux/crash_dump.h> +#include <linux/crash_core.h> + +MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>"); +MODULE_DESCRIPTION("QEMU fw_cfg sysfs support"); +MODULE_LICENSE("GPL"); + +/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */ +static u32 fw_cfg_rev; + +/* 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; +static void __iomem *fw_cfg_reg_dma; + +/* 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 void fw_cfg_sel_endianness(u16 key) +{ + if (fw_cfg_is_mmio) + iowrite16be(key, fw_cfg_reg_ctrl); + else + iowrite16(key, fw_cfg_reg_ctrl); +} + +#ifdef CONFIG_CRASH_CORE +static inline bool fw_cfg_dma_enabled(void) +{ + return (fw_cfg_rev & FW_CFG_VERSION_DMA) && fw_cfg_reg_dma; +} + +/* qemu fw_cfg device is sync today, but spec says it may become async */ +static void fw_cfg_wait_for_control(struct fw_cfg_dma_access *d) +{ + for (;;) { + u32 ctrl = be32_to_cpu(READ_ONCE(d->control)); + + /* do not reorder the read to d->control */ + rmb(); + if ((ctrl & ~FW_CFG_DMA_CTL_ERROR) == 0) + return; + + cpu_relax(); + } +} + +static ssize_t fw_cfg_dma_transfer(void *address, u32 length, u32 control) +{ + phys_addr_t dma; + struct fw_cfg_dma_access *d = NULL; + ssize_t ret = length; + + d = kmalloc(sizeof(*d), GFP_KERNEL); + if (!d) { + ret = -ENOMEM; + goto end; + } + + /* fw_cfg device does not need IOMMU protection, so use physical addresses */ + *d = (struct fw_cfg_dma_access) { + .address = cpu_to_be64(address ? virt_to_phys(address) : 0), + .length = cpu_to_be32(length), + .control = cpu_to_be32(control) + }; + + dma = virt_to_phys(d); + + iowrite32be((u64)dma >> 32, fw_cfg_reg_dma); + /* force memory to sync before notifying device via MMIO */ + wmb(); + iowrite32be(dma, fw_cfg_reg_dma + 4); + + fw_cfg_wait_for_control(d); + + if (be32_to_cpu(READ_ONCE(d->control)) & FW_CFG_DMA_CTL_ERROR) { + ret = -EIO; + } + +end: + kfree(d); + + return ret; +} +#endif + +/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */ +static ssize_t fw_cfg_read_blob(u16 key, + void *buf, loff_t pos, size_t count) +{ + u32 glk = -1U; + acpi_status status; + + /* If we have ACPI, ensure mutual exclusion against any potential + * device access by the firmware, e.g. via AML methods: + */ + status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk); + if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) { + /* Should never get here */ + WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n"); + memset(buf, 0, count); + return -EINVAL; + } + + mutex_lock(&fw_cfg_dev_lock); + fw_cfg_sel_endianness(key); + while (pos-- > 0) + ioread8(fw_cfg_reg_data); + ioread8_rep(fw_cfg_reg_data, buf, count); + mutex_unlock(&fw_cfg_dev_lock); + + acpi_release_global_lock(glk); + return count; +} + +#ifdef CONFIG_CRASH_CORE +/* write chunk of given fw_cfg blob (caller responsible for sanity-check) */ +static ssize_t fw_cfg_write_blob(u16 key, + void *buf, loff_t pos, size_t count) +{ + u32 glk = -1U; + acpi_status status; + ssize_t ret = count; + + /* If we have ACPI, ensure mutual exclusion against any potential + * device access by the firmware, e.g. via AML methods: + */ + status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk); + if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) { + /* Should never get here */ + WARN(1, "%s: Failed to lock ACPI!\n", __func__); + return -EINVAL; + } + + mutex_lock(&fw_cfg_dev_lock); + if (pos == 0) { + ret = fw_cfg_dma_transfer(buf, count, key << 16 + | FW_CFG_DMA_CTL_SELECT + | FW_CFG_DMA_CTL_WRITE); + } else { + fw_cfg_sel_endianness(key); + ret = fw_cfg_dma_transfer(NULL, pos, FW_CFG_DMA_CTL_SKIP); + if (ret < 0) + goto end; + ret = fw_cfg_dma_transfer(buf, count, FW_CFG_DMA_CTL_WRITE); + } + +end: + mutex_unlock(&fw_cfg_dev_lock); + + acpi_release_global_lock(glk); + + return ret; +} +#endif /* CONFIG_CRASH_CORE */ + +/* 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_CFG_DATA_OFF)) +# if (defined(CONFIG_ARM) || defined(CONFIG_ARM64)) +# define FW_CFG_CTRL_OFF 0x08 +# define FW_CFG_DATA_OFF 0x00 +# define FW_CFG_DMA_OFF 0x10 +# elif defined(CONFIG_PARISC) /* parisc */ +# define FW_CFG_CTRL_OFF 0x00 +# define FW_CFG_DATA_OFF 0x04 +# 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 +# define FW_CFG_DMA_OFF 0x04 +# else +# error "QEMU FW_CFG not available on this architecture!" +# 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, *dma; + + /* 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"); + dma = platform_get_resource_byname(pdev, IORESOURCE_REG, "dma"); + 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; + } + + if (dma) + fw_cfg_reg_dma = fw_cfg_dev_base + dma->start; +#ifdef FW_CFG_DMA_OFF + else + fw_cfg_reg_dma = fw_cfg_dev_base + FW_CFG_DMA_OFF; +#endif + + /* verify fw_cfg device signature */ + if (fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, + 0, FW_CFG_SIG_SIZE) < 0 || + memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) { + fw_cfg_io_cleanup(); + return -ENODEV; + } + + return 0; +} + +static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a, + char *buf) +{ + return sprintf(buf, "%u\n", fw_cfg_rev); +} + +static const struct kobj_attribute 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; + u32 size; + u16 select; + char name[FW_CFG_MAX_FILE_PATH]; + struct list_head list; +}; + +#ifdef CONFIG_CRASH_CORE +static ssize_t fw_cfg_write_vmcoreinfo(const struct fw_cfg_file *f) +{ + static struct fw_cfg_vmcoreinfo *data; + ssize_t ret; + + data = kmalloc(sizeof(struct fw_cfg_vmcoreinfo), GFP_KERNEL); + if (!data) + return -ENOMEM; + + *data = (struct fw_cfg_vmcoreinfo) { + .guest_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF), + .size = cpu_to_le32(VMCOREINFO_NOTE_SIZE), + .paddr = cpu_to_le64(paddr_vmcoreinfo_note()) + }; + /* spare ourself reading host format support for now since we + * don't know what else to format - host may ignore ours + */ + ret = fw_cfg_write_blob(be16_to_cpu(f->select), data, + 0, sizeof(struct fw_cfg_vmcoreinfo)); + + kfree(data); + return ret; +} +#endif /* CONFIG_CRASH_CORE */ + +/* 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) { + fw_cfg_sysfs_cache_delist(entry); + kobject_del(&entry->kobj); + kobject_put(&entry->kobj); + } +} + +/* 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->size); +} + +static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf) +{ + return sprintf(buf, "%u\n", e->select); +} + +static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf) +{ + return sprintf(buf, "%s\n", e->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, +}; +ATTRIBUTE_GROUPS(fw_cfg_sysfs_entry); + +/* 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); + + kfree(entry); +} + +/* kobj_type: ties together all properties required to register an entry */ +static struct kobj_type fw_cfg_sysfs_entry_ktype = { + .default_groups = fw_cfg_sysfs_entry_groups, + .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->size) + return -EINVAL; + + if (count > entry->size - pos) + count = entry->size - pos; + + return fw_cfg_read_blob(entry->select, buf, pos, count); +} + +static struct bin_attribute fw_cfg_sysfs_attr_raw = { + .attr = { .name = "raw", .mode = S_IRUSR }, + .read = fw_cfg_sysfs_read_raw, +}; + +/* + * Create a kset subdirectory matching each '/' delimited dirname token + * in 'name', starting with sysfs kset/folder 'dir'; At the end, create + * a symlink directed at the given 'target'. + * NOTE: We do this on a best-effort basis, since 'name' is not guaranteed + * to be a well-behaved path name. Whenever a symlink vs. kset directory + * name collision occurs, the kernel will issue big scary warnings while + * refusing to add the offending link or directory. We follow up with our + * own, slightly less scary error messages explaining the situation :) + */ +static int fw_cfg_build_symlink(struct kset *dir, + struct kobject *target, const char *name) +{ + int ret; + struct kset *subdir; + struct kobject *ko; + char *name_copy, *p, *tok; + + if (!dir || !target || !name || !*name) + return -EINVAL; + + /* clone a copy of name for parsing */ + name_copy = p = kstrdup(name, GFP_KERNEL); + if (!name_copy) + return -ENOMEM; + + /* create folders for each dirname token, then symlink for basename */ + while ((tok = strsep(&p, "/")) && *tok) { + + /* last (basename) token? If so, add symlink here */ + if (!p || !*p) { + ret = sysfs_create_link(&dir->kobj, target, tok); + break; + } + + /* does the current dir contain an item named after tok ? */ + ko = kset_find_obj(dir, tok); + if (ko) { + /* drop reference added by kset_find_obj */ + kobject_put(ko); + + /* ko MUST be a kset - we're about to use it as one ! */ + if (ko->ktype != dir->kobj.ktype) { + ret = -EINVAL; + break; + } + + /* descend into already existing subdirectory */ + dir = to_kset(ko); + } else { + /* create new subdirectory kset */ + subdir = kzalloc(sizeof(struct kset), GFP_KERNEL); + if (!subdir) { + ret = -ENOMEM; + break; + } + subdir->kobj.kset = dir; + subdir->kobj.ktype = dir->kobj.ktype; + ret = kobject_set_name(&subdir->kobj, "%s", tok); + if (ret) { + kfree(subdir); + break; + } + ret = kset_register(subdir); + if (ret) { + kfree(subdir); + break; + } + + /* descend into newly created subdirectory */ + dir = subdir; + } + } + + /* we're done with cloned copy of name */ + kfree(name_copy); + return ret; +} + +/* recursively unregister fw_cfg/by_name/ kset directory tree */ +static void fw_cfg_kset_unregister_recursive(struct kset *kset) +{ + struct kobject *k, *next; + + list_for_each_entry_safe(k, next, &kset->list, entry) + /* all set members are ksets too, but check just in case... */ + if (k->ktype == kset->kobj.ktype) + fw_cfg_kset_unregister_recursive(to_kset(k)); + + /* symlinks are cleanly and automatically removed with the directory */ + kset_unregister(kset); +} + +/* 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; +static struct kset *fw_cfg_fname_kset; + +/* 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; + +#ifdef CONFIG_CRASH_CORE + if (fw_cfg_dma_enabled() && + strcmp(f->name, FW_CFG_VMCOREINFO_FILENAME) == 0 && + !is_kdump_kernel()) { + if (fw_cfg_write_vmcoreinfo(f) < 0) + pr_warn("fw_cfg: failed to write vmcoreinfo"); + } +#endif + + /* allocate new entry */ + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return -ENOMEM; + + /* set file entry information */ + entry->size = be32_to_cpu(f->size); + entry->select = be16_to_cpu(f->select); + strscpy(entry->name, f->name, FW_CFG_MAX_FILE_PATH); + + /* 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->select); + if (err) + goto err_put_entry; + + /* add raw binary content access */ + err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw); + if (err) + goto err_del_entry; + + /* try adding "/sys/firmware/qemu_fw_cfg/by_name/" symlink */ + fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->name); + + /* success, add entry to global cache */ + fw_cfg_sysfs_cache_enlist(entry); + return 0; + +err_del_entry: + kobject_del(&entry->kobj); +err_put_entry: + kobject_put(&entry->kobj); + return err; +} + +/* iterate over all fw_cfg directory entries, registering each one */ +static int fw_cfg_register_dir_entries(void) +{ + int ret = 0; + __be32 files_count; + u32 count, i; + struct fw_cfg_file *dir; + size_t dir_size; + + ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, &files_count, + 0, sizeof(files_count)); + if (ret < 0) + return ret; + + count = be32_to_cpu(files_count); + dir_size = count * sizeof(struct fw_cfg_file); + + dir = kmalloc(dir_size, GFP_KERNEL); + if (!dir) + return -ENOMEM; + + ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, + sizeof(files_count), dir_size); + if (ret < 0) + goto end; + + for (i = 0; i < count; i++) { + ret = fw_cfg_register_file(&dir[i]); + if (ret) + break; + } + +end: + 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; + __le32 rev; + + /* 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 (and by_name) 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 and by_name subdirs 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; + fw_cfg_fname_kset = kset_create_and_add("by_name", NULL, fw_cfg_top_ko); + if (!fw_cfg_fname_kset) + goto err_name; + + /* 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 */ + err = fw_cfg_read_blob(FW_CFG_ID, &rev, 0, sizeof(rev)); + if (err < 0) + goto err_probe; + + fw_cfg_rev = le32_to_cpu(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_kset_unregister_recursive(fw_cfg_fname_kset); +err_name: + 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(); + sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); + fw_cfg_io_cleanup(); + fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset); + fw_cfg_kobj_cleanup(fw_cfg_sel_ko); + 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[] = { + { FW_CFG_ACPI_DEVICE_ID, }, + {}, +}; +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" \ + ":%" __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" + +#define PH_ADDR_PR_4_FMT PH_ADDR_PR_3_FMT \ + ":%" __PHYS_ADDR_PREFIX "u" + +static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp) +{ + struct resource res[4] = {}; + char *str; + phys_addr_t base; + resource_size_t size, ctrl_off, data_off, dma_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>[:<dma_off>]]" chunks */ + processed = sscanf(str, PH_ADDR_SCAN_FMT, + &base, &consumed, + &ctrl_off, &data_off, &consumed, + &dma_off, &consumed); + + /* sscanf() must process precisely 1, 3 or 4 chunks: + * <base> is mandatory, optionally followed by <ctrl_off> + * and <data_off>, and <dma_off>; + * there must be no extra characters after the last chunk, + * so str[consumed] must be '\0'. + */ + if (str[consumed] || + (processed != 1 && processed != 3 && processed != 4)) + 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; + } + if (processed > 3) { + res[3].name = "dma"; + res[3].start = dma_off; + res[3].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); + + return PTR_ERR_OR_ZERO(fw_cfg_cmdline_dev); +} + +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); + case 4: + return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_4_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, + fw_cfg_cmdline_dev->resource[3].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) +{ + int ret; + + /* 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; + + ret = platform_driver_register(&fw_cfg_sysfs_driver); + if (ret) + fw_cfg_kobj_cleanup(fw_cfg_top_ko); + + return ret; +} + +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); |