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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/mips/bcm47xx/nvram.c
10817 views
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/*

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 * BCM947xx nvram variable access

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 *

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 * Copyright (C) 2005 Broadcom Corporation

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 * Copyright (C) 2006 Felix Fietkau <[email protected]>

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 * Copyright (C) 2010-2011 Hauke Mehrtens <[email protected]>

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 *

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 * This program is free software; you can redistribute  it and/or modify it

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 * under  the terms of  the GNU General  Public License as published by the

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 * Free Software Foundation;  either version 2 of the  License, or (at your

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 * option) any later version.

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 */

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#include <linux/init.h>

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#include <linux/types.h>

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#include <linux/module.h>

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#include <linux/ssb/ssb.h>

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#include <linux/kernel.h>

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#include <linux/string.h>

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#include <asm/addrspace.h>

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#include <asm/mach-bcm47xx/nvram.h>

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#include <asm/mach-bcm47xx/bcm47xx.h>

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static char nvram_buf[NVRAM_SPACE];

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/* Probe for NVRAM header */

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static void early_nvram_init(void)

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{

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	struct ssb_mipscore *mcore = &ssb_bcm47xx.mipscore;

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	struct nvram_header *header;

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	int i;

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	u32 base, lim, off;

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	u32 *src, *dst;

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	base = mcore->flash_window;

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	lim = mcore->flash_window_size;

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	off = FLASH_MIN;

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	while (off <= lim) {

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		/* Windowed flash access */

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		header = (struct nvram_header *)

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			KSEG1ADDR(base + off - NVRAM_SPACE);

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		if (header->magic == NVRAM_HEADER)

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			goto found;

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		off <<= 1;

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	}

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	/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */

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	header = (struct nvram_header *) KSEG1ADDR(base + 4096);

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	if (header->magic == NVRAM_HEADER)

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		goto found;

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	header = (struct nvram_header *) KSEG1ADDR(base + 1024);

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	if (header->magic == NVRAM_HEADER)

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		goto found;

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	return;

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found:

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	src = (u32 *) header;

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	dst = (u32 *) nvram_buf;

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	for (i = 0; i < sizeof(struct nvram_header); i += 4)

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		*dst++ = *src++;

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	for (; i < header->len && i < NVRAM_SPACE; i += 4)

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		*dst++ = le32_to_cpu(*src++);

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}

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int nvram_getenv(char *name, char *val, size_t val_len)

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{

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	char *var, *value, *end, *eq;

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	if (!name)

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		return NVRAM_ERR_INV_PARAM;

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	if (!nvram_buf[0])

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		early_nvram_init();

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	/* Look for name=value and return value */

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	var = &nvram_buf[sizeof(struct nvram_header)];

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	end = nvram_buf + sizeof(nvram_buf) - 2;

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	end[0] = end[1] = '\0';

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	for (; *var; var = value + strlen(value) + 1) {

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		eq = strchr(var, '=');

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		if (!eq)

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			break;

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		value = eq + 1;

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		if ((eq - var) == strlen(name) &&

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			strncmp(var, name, (eq - var)) == 0) {

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			snprintf(val, val_len, "%s", value);

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			return 0;

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		}

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	}

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	return NVRAM_ERR_ENVNOTFOUND;

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}

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EXPORT_SYMBOL(nvram_getenv);

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