/* * 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/vmcore_info.h> MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …; /* 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) { … } #ifdef CONFIG_VMCORE_INFO static inline bool fw_cfg_dma_enabled(void) { … } /* 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) { … } static ssize_t fw_cfg_dma_transfer(void *address, u32 length, u32 control) { … } #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) { … } #ifdef CONFIG_VMCORE_INFO /* 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) { … } #endif /* CONFIG_VMCORE_INFO */ /* clean up fw_cfg device i/o */ static void fw_cfg_io_cleanup(void) { … } /* 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) || defined(CONFIG_RISCV)) #define FW_CFG_CTRL_OFF … #define FW_CFG_DATA_OFF … #define FW_CFG_DMA_OFF … # elif defined(CONFIG_PARISC) /* parisc */ #define FW_CFG_CTRL_OFF … #define FW_CFG_DATA_OFF … # elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */ #define FW_CFG_CTRL_OFF … #define FW_CFG_DATA_OFF … # elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */ #define FW_CFG_CTRL_OFF … #define FW_CFG_DATA_OFF … #define FW_CFG_DMA_OFF … # 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) { … } static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a, char *buf) { … } static const struct kobj_attribute fw_cfg_rev_attr = …; /* fw_cfg_sysfs_entry type */ struct fw_cfg_sysfs_entry { … }; #ifdef CONFIG_VMCORE_INFO static ssize_t fw_cfg_write_vmcoreinfo(const struct fw_cfg_file *f) { … } #endif /* CONFIG_VMCORE_INFO */ /* get fw_cfg_sysfs_entry from kobject member */ static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj) { … } /* fw_cfg_sysfs_attribute type */ struct fw_cfg_sysfs_attribute { … }; /* get fw_cfg_sysfs_attribute from attribute member */ static inline struct fw_cfg_sysfs_attribute *to_attr(struct 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) { … } static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry) { … } static void fw_cfg_sysfs_cache_cleanup(void) { … } /* per-entry attributes and show methods */ #define FW_CFG_SYSFS_ATTR(_attr) … static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf) { … } static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf) { … } static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf) { … } 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[] = …; ATTRIBUTE_GROUPS(…); /* 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) { … } static const struct sysfs_ops fw_cfg_sysfs_attr_ops = …; /* release: destructor, to be called via kobject_put() */ static void fw_cfg_sysfs_release_entry(struct kobject *kobj) { … } /* kobj_type: ties together all properties required to register an entry */ static struct kobj_type fw_cfg_sysfs_entry_ktype = …; /* 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) { … } static struct bin_attribute fw_cfg_sysfs_attr_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) { … } /* recursively unregister fw_cfg/by_name/ kset directory tree */ static void fw_cfg_kset_unregister_recursive(struct kset *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) { … } /* iterate over all fw_cfg directory entries, registering each one */ static int fw_cfg_register_dir_entries(void) { … } /* unregister top-level or by_key folder */ static inline void fw_cfg_kobj_cleanup(struct kobject *kobj) { … } static int fw_cfg_sysfs_probe(struct platform_device *pdev) { … } static void fw_cfg_sysfs_remove(struct platform_device *pdev) { … } static const struct of_device_id fw_cfg_sysfs_mmio_match[] = …; MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match); #ifdef CONFIG_ACPI static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = …; MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match); #endif static struct platform_driver fw_cfg_sysfs_driver = …; #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 … #else #define __PHYS_ADDR_PREFIX … #endif /* use special scanf/printf modifier for phys_addr_t, resource_size_t */ #define PH_ADDR_SCAN_FMT … #define PH_ADDR_PR_1_FMT … #define PH_ADDR_PR_3_FMT … #define PH_ADDR_PR_4_FMT … static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp) { … } static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp) { … } static const struct kernel_param_ops fw_cfg_cmdline_param_ops = …; device_param_cb(…); device_param_cb(…); #endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */ static int __init fw_cfg_sysfs_init(void) { … } static void __exit fw_cfg_sysfs_exit(void) { … } module_init(…) …; module_exit(fw_cfg_sysfs_exit);
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