[linux-block.git] / include / linux / nvram.h

/* 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 */
Commit	Line	Data
	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	#ifndef _LINUX_NVRAM_H
	3	#define _LINUX_NVRAM_H
	4
	5	#include <linux/errno.h>
	6	#include <uapi/linux/nvram.h>
	7
	8	#ifdef CONFIG_PPC
	9	#include <asm/machdep.h>
	10	#endif
	11
	12	/**
	13	* struct nvram_ops - NVRAM functionality made available to drivers
	14	* @read: validate checksum (if any) then load a range of bytes from NVRAM
	15	* @write: store a range of bytes to NVRAM then update checksum (if any)
	16	* @read_byte: load a single byte from NVRAM
	17	* @write_byte: store a single byte to NVRAM
	18	* @get_size: return the fixed number of bytes in the NVRAM
	19	*
	20	* Architectures which provide an nvram ops struct need not implement all
	21	* of these methods. If the NVRAM hardware can be accessed only one byte
	22	* at a time then it may be sufficient to provide .read_byte and .write_byte.
	23	* If the NVRAM has a checksum (and it is to be checked) the .read and
	24	* .write methods can be used to implement that efficiently.
	25	*
	26	* Portable drivers may use the wrapper functions defined here.
	27	* The nvram_read() and nvram_write() functions call the .read and .write
	28	* methods when available and fall back on the .read_byte and .write_byte
	29	* methods otherwise.
	30	*/
	31
	32	struct nvram_ops {
	33	ssize_t (*get_size)(void);
	34	unsigned char (*read_byte)(int);
	35	void (*write_byte)(unsigned char, int);
	36	ssize_t (read)(char , size_t, loff_t *);
	37	ssize_t (write)(char , size_t, loff_t *);
	38	#if defined(CONFIG_X86) \|\| defined(CONFIG_M68K)
	39	long (*initialize)(void);
	40	long (*set_checksum)(void);
	41	#endif
	42	};
	43
	44	extern const struct nvram_ops arch_nvram_ops;
	45
	46	static inline ssize_t nvram_get_size(void)
	47	{
	48	#ifdef CONFIG_PPC
	49	if (ppc_md.nvram_size)
	50	return ppc_md.nvram_size();
	51	#else
	52	if (arch_nvram_ops.get_size)
	53	return arch_nvram_ops.get_size();
	54	#endif
	55	return -ENODEV;
	56	}
	57
	58	static inline unsigned char nvram_read_byte(int addr)
	59	{
	60	#ifdef CONFIG_PPC
	61	if (ppc_md.nvram_read_val)
	62	return ppc_md.nvram_read_val(addr);
	63	#else
	64	if (arch_nvram_ops.read_byte)
	65	return arch_nvram_ops.read_byte(addr);
	66	#endif
	67	return 0xFF;
	68	}
	69
	70	static inline void nvram_write_byte(unsigned char val, int addr)
	71	{
	72	#ifdef CONFIG_PPC
	73	if (ppc_md.nvram_write_val)
	74	ppc_md.nvram_write_val(addr, val);
	75	#else
	76	if (arch_nvram_ops.write_byte)
	77	arch_nvram_ops.write_byte(val, addr);
	78	#endif
	79	}
	80
	81	static inline ssize_t nvram_read_bytes(char buf, size_t count, loff_t ppos)
	82	{
	83	ssize_t nvram_size = nvram_get_size();
	84	loff_t i;
	85	char *p = buf;
	86
	87	if (nvram_size < 0)
	88	return nvram_size;
	89	for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count)
	90	*p = nvram_read_byte(i);
	91	*ppos = i;
	92	return p - buf;
	93	}
	94
	95	static inline ssize_t nvram_write_bytes(char buf, size_t count, loff_t ppos)
	96	{
	97	ssize_t nvram_size = nvram_get_size();
	98	loff_t i;
	99	char *p = buf;
	100
	101	if (nvram_size < 0)
	102	return nvram_size;
	103	for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count)
	104	nvram_write_byte(*p, i);
	105	*ppos = i;
	106	return p - buf;
	107	}
	108
	109	static inline ssize_t nvram_read(char buf, size_t count, loff_t ppos)
	110	{
	111	#ifdef CONFIG_PPC
	112	if (ppc_md.nvram_read)
	113	return ppc_md.nvram_read(buf, count, ppos);
	114	#else
	115	if (arch_nvram_ops.read)
	116	return arch_nvram_ops.read(buf, count, ppos);
	117	#endif
	118	return nvram_read_bytes(buf, count, ppos);
	119	}
	120
	121	static inline ssize_t nvram_write(char buf, size_t count, loff_t ppos)
	122	{
	123	#ifdef CONFIG_PPC
	124	if (ppc_md.nvram_write)
	125	return ppc_md.nvram_write(buf, count, ppos);
	126	#else
	127	if (arch_nvram_ops.write)
	128	return arch_nvram_ops.write(buf, count, ppos);
	129	#endif
	130	return nvram_write_bytes(buf, count, ppos);
	131	}
	132
	133	#endif /* _LINUX_NVRAM_H */