123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133 |
- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef _LINUX_NVRAM_H
- #define _LINUX_NVRAM_H
- #include <linux/errno.h>
- #include <uapi/linux/nvram.h>
- #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 */
|