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133 lines
3.5 KiB
133 lines
3.5 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef _LINUX_NVRAM_H |
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#define _LINUX_NVRAM_H |
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#include <linux/errno.h> |
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#include <uapi/linux/nvram.h> |
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#ifdef CONFIG_PPC |
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#include <asm/machdep.h> |
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#endif |
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/** |
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* struct nvram_ops - NVRAM functionality made available to drivers |
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* @read: validate checksum (if any) then load a range of bytes from NVRAM |
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* @write: store a range of bytes to NVRAM then update checksum (if any) |
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* @read_byte: load a single byte from NVRAM |
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* @write_byte: store a single byte to NVRAM |
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* @get_size: return the fixed number of bytes in the NVRAM |
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* |
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* Architectures which provide an nvram ops struct need not implement all |
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* of these methods. If the NVRAM hardware can be accessed only one byte |
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* at a time then it may be sufficient to provide .read_byte and .write_byte. |
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* If the NVRAM has a checksum (and it is to be checked) the .read and |
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* .write methods can be used to implement that efficiently. |
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* |
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* Portable drivers may use the wrapper functions defined here. |
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* The nvram_read() and nvram_write() functions call the .read and .write |
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* methods when available and fall back on the .read_byte and .write_byte |
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* methods otherwise. |
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*/ |
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struct nvram_ops { |
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ssize_t (*get_size)(void); |
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unsigned char (*read_byte)(int); |
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void (*write_byte)(unsigned char, int); |
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ssize_t (*read)(char *, size_t, loff_t *); |
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ssize_t (*write)(char *, size_t, loff_t *); |
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#if defined(CONFIG_X86) || defined(CONFIG_M68K) |
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long (*initialize)(void); |
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long (*set_checksum)(void); |
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#endif |
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}; |
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extern const struct nvram_ops arch_nvram_ops; |
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static inline ssize_t nvram_get_size(void) |
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{ |
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#ifdef CONFIG_PPC |
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if (ppc_md.nvram_size) |
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return ppc_md.nvram_size(); |
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#else |
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if (arch_nvram_ops.get_size) |
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return arch_nvram_ops.get_size(); |
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#endif |
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return -ENODEV; |
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} |
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static inline unsigned char nvram_read_byte(int addr) |
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{ |
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#ifdef CONFIG_PPC |
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if (ppc_md.nvram_read_val) |
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return ppc_md.nvram_read_val(addr); |
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#else |
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if (arch_nvram_ops.read_byte) |
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return arch_nvram_ops.read_byte(addr); |
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#endif |
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return 0xFF; |
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} |
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static inline void nvram_write_byte(unsigned char val, int addr) |
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{ |
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#ifdef CONFIG_PPC |
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if (ppc_md.nvram_write_val) |
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ppc_md.nvram_write_val(addr, val); |
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#else |
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if (arch_nvram_ops.write_byte) |
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arch_nvram_ops.write_byte(val, addr); |
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#endif |
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} |
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static inline ssize_t nvram_read_bytes(char *buf, size_t count, loff_t *ppos) |
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{ |
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ssize_t nvram_size = nvram_get_size(); |
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loff_t i; |
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char *p = buf; |
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if (nvram_size < 0) |
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return nvram_size; |
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for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count) |
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*p = nvram_read_byte(i); |
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*ppos = i; |
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return p - buf; |
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} |
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static inline ssize_t nvram_write_bytes(char *buf, size_t count, loff_t *ppos) |
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{ |
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ssize_t nvram_size = nvram_get_size(); |
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loff_t i; |
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char *p = buf; |
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if (nvram_size < 0) |
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return nvram_size; |
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for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count) |
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nvram_write_byte(*p, i); |
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*ppos = i; |
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return p - buf; |
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} |
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static inline ssize_t nvram_read(char *buf, size_t count, loff_t *ppos) |
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{ |
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#ifdef CONFIG_PPC |
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if (ppc_md.nvram_read) |
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return ppc_md.nvram_read(buf, count, ppos); |
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#else |
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if (arch_nvram_ops.read) |
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return arch_nvram_ops.read(buf, count, ppos); |
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#endif |
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return nvram_read_bytes(buf, count, ppos); |
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} |
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static inline ssize_t nvram_write(char *buf, size_t count, loff_t *ppos) |
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{ |
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#ifdef CONFIG_PPC |
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if (ppc_md.nvram_write) |
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return ppc_md.nvram_write(buf, count, ppos); |
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#else |
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if (arch_nvram_ops.write) |
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return arch_nvram_ops.write(buf, count, ppos); |
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#endif |
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return nvram_write_bytes(buf, count, ppos); |
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} |
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#endif /* _LINUX_NVRAM_H */
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