diff options
Diffstat (limited to 'include/linux/nvram.h')
| -rw-r--r-- | include/linux/nvram.h | 133 |
1 files changed, 126 insertions, 7 deletions
diff --git a/include/linux/nvram.h b/include/linux/nvram.h index 28bfb9ab94ca..d29d9c93a927 100644 --- a/include/linux/nvram.h +++ b/include/linux/nvram.h @@ -2,13 +2,132 @@ #ifndef _LINUX_NVRAM_H #define _LINUX_NVRAM_H +#include <linux/errno.h> #include <uapi/linux/nvram.h> -/* __foo is foo without grabbing the rtc_lock - get it yourself */ -extern unsigned char __nvram_read_byte(int i); -extern unsigned char nvram_read_byte(int i); -extern void __nvram_write_byte(unsigned char c, int i); -extern void nvram_write_byte(unsigned char c, int i); -extern int __nvram_check_checksum(void); -extern int nvram_check_checksum(void); +#ifdef CONFIG_PPC +#include <asm/machdep.h> +#endif + +/** + * struct nvram_ops - NVRAM functionality made available to drivers + * @read: validate checksum (if any) then load a range of bytes from NVRAM + * @write: store a range of bytes to NVRAM then update checksum (if any) + * @read_byte: load a single byte from NVRAM + * @write_byte: store a single byte to NVRAM + * @get_size: return the fixed number of bytes in the NVRAM + * + * Architectures which provide an nvram ops struct need not implement all + * of these methods. If the NVRAM hardware can be accessed only one byte + * at a time then it may be sufficient to provide .read_byte and .write_byte. + * If the NVRAM has a checksum (and it is to be checked) the .read and + * .write methods can be used to implement that efficiently. + * + * Portable drivers may use the wrapper functions defined here. + * The nvram_read() and nvram_write() functions call the .read and .write + * methods when available and fall back on the .read_byte and .write_byte + * methods otherwise. + */ + +struct nvram_ops { + ssize_t (*get_size)(void); + unsigned char (*read_byte)(int); + void (*write_byte)(unsigned char, int); + ssize_t (*read)(char *, size_t, loff_t *); + ssize_t (*write)(char *, size_t, loff_t *); +#if defined(CONFIG_X86) || defined(CONFIG_M68K) + long (*initialize)(void); + long (*set_checksum)(void); +#endif +}; + +extern const struct nvram_ops arch_nvram_ops; + +static inline ssize_t nvram_get_size(void) +{ +#ifdef CONFIG_PPC + if (ppc_md.nvram_size) + return ppc_md.nvram_size(); +#else + if (arch_nvram_ops.get_size) + return arch_nvram_ops.get_size(); +#endif + return -ENODEV; +} + +static inline unsigned char nvram_read_byte(int addr) +{ +#ifdef CONFIG_PPC + if (ppc_md.nvram_read_val) + return ppc_md.nvram_read_val(addr); +#else + if (arch_nvram_ops.read_byte) + return arch_nvram_ops.read_byte(addr); +#endif + return 0xFF; +} + +static inline void nvram_write_byte(unsigned char val, int addr) +{ +#ifdef CONFIG_PPC + if (ppc_md.nvram_write_val) + ppc_md.nvram_write_val(addr, val); +#else + if (arch_nvram_ops.write_byte) + arch_nvram_ops.write_byte(val, addr); +#endif +} + +static inline ssize_t nvram_read_bytes(char *buf, size_t count, loff_t *ppos) +{ + ssize_t nvram_size = nvram_get_size(); + loff_t i; + char *p = buf; + + if (nvram_size < 0) + return nvram_size; + for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count) + *p = nvram_read_byte(i); + *ppos = i; + return p - buf; +} + +static inline ssize_t nvram_write_bytes(char *buf, size_t count, loff_t *ppos) +{ + ssize_t nvram_size = nvram_get_size(); + loff_t i; + char *p = buf; + + if (nvram_size < 0) + return nvram_size; + for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count) + nvram_write_byte(*p, i); + *ppos = i; + return p - buf; +} + +static inline ssize_t nvram_read(char *buf, size_t count, loff_t *ppos) +{ +#ifdef CONFIG_PPC + if (ppc_md.nvram_read) + return ppc_md.nvram_read(buf, count, ppos); +#else + if (arch_nvram_ops.read) + return arch_nvram_ops.read(buf, count, ppos); +#endif + return nvram_read_bytes(buf, count, ppos); +} + +static inline ssize_t nvram_write(char *buf, size_t count, loff_t *ppos) +{ +#ifdef CONFIG_PPC + if (ppc_md.nvram_write) + return ppc_md.nvram_write(buf, count, ppos); +#else + if (arch_nvram_ops.write) + return arch_nvram_ops.write(buf, count, ppos); +#endif + return nvram_write_bytes(buf, count, ppos); +} + #endif /* _LINUX_NVRAM_H */ |