v4.19.13 snapshot.
diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
new file mode 100644
index 0000000..039e0f9
--- /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_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 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;
+ 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) {
+ /* 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->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,
+};
+
+/* 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->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);
+ memcpy(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_register;
+
+ /* add raw binary content access */
+ err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw);
+ if (err)
+ goto err_add_raw;
+
+ /* 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_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;
+ __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);