bcm53xx: backport NVRAM driver sent upstream

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

SVN-Revision: 43612

target/linux/bcm53xx/files/drivers/firmware/broadcom/Kconfig

@@ -0,0 +1,11 @@
+config BCM47XX_NVRAM
+	bool "Broadcom NVRAM driver"
+	depends on BCM47XX || ARCH_BCM_5301X
+	help
+	  Broadcom home routers contain flash partition called "nvram" with all
+	  important hardware configuration as well as some minor user setup.
+	  NVRAM partition contains a text-like data representing name=value
+	  pairs.
+	  This driver provides an easy way to get value of requested parameter.
+	  It simply reads content of NVRAM and parses it. It doesn't control any
+	  hardware part itself.

target/linux/bcm53xx/files/drivers/firmware/broadcom/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_BCM47XX_NVRAM)		+= bcm47xx_nvram.o

target/linux/bcm53xx/files/drivers/firmware/broadcom/bcm47xx_nvram.c

@@ -0,0 +1,232 @@
+/*
+ * BCM947xx nvram variable access
+ *
+ * Copyright (C) 2005 Broadcom Corporation
+ * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de>
+ *
+ * This program is free software; you can redistribute	it and/or modify it
+ * under  the terms of	the GNU General	 Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/mtd/mtd.h>
+#include <linux/bcm47xx_nvram.h>
+
+#define NVRAM_MAGIC			0x48534C46	/* 'FLSH' */
+#define NVRAM_SPACE			0x8000
+#define NVRAM_MAX_GPIO_ENTRIES		32
+#define NVRAM_MAX_GPIO_VALUE_LEN	30
+
+#define FLASH_MIN		0x00020000	/* Minimum flash size */
+
+struct nvram_header {
+	u32 magic;
+	u32 len;
+	u32 crc_ver_init;	/* 0:7 crc, 8:15 ver, 16:31 sdram_init */
+	u32 config_refresh;	/* 0:15 sdram_config, 16:31 sdram_refresh */
+	u32 config_ncdl;	/* ncdl values for memc */
+};
+
+static char nvram_buf[NVRAM_SPACE];
+static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
+
+static u32 find_nvram_size(void __iomem *end)
+{
+	struct nvram_header __iomem *header;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
+		header = (struct nvram_header *)(end - nvram_sizes[i]);
+		if (header->magic == NVRAM_MAGIC)
+			return nvram_sizes[i];
+	}
+
+	return 0;
+}
+
+/* Probe for NVRAM header */
+static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
+{
+	struct nvram_header __iomem *header;
+	int i;
+	u32 off;
+	u32 *src, *dst;
+	u32 size;
+
+	if (nvram_buf[0]) {
+		pr_warn("nvram already initialized\n");
+		return -EEXIST;
+	}
+
+	/* TODO: when nvram is on nand flash check for bad blocks first. */
+	off = FLASH_MIN;
+	while (off <= lim) {
+		/* Windowed flash access */
+		size = find_nvram_size(iobase + off);
+		if (size) {
+			header = (struct nvram_header *)(iobase + off - size);
+			goto found;
+		}
+		off <<= 1;
+	}
+
+	/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
+	header = (struct nvram_header *)(iobase + 4096);
+	if (header->magic == NVRAM_MAGIC) {
+		size = NVRAM_SPACE;
+		goto found;
+	}
+
+	header = (struct nvram_header *)(iobase + 1024);
+	if (header->magic == NVRAM_MAGIC) {
+		size = NVRAM_SPACE;
+		goto found;
+	}
+
+	pr_err("no nvram found\n");
+	return -ENXIO;
+
+found:
+	if (header->len > size)
+		pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
+	if (header->len > NVRAM_SPACE)
+		pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
+		       header->len, NVRAM_SPACE);
+
+	src = (u32 *)header;
+	dst = (u32 *)nvram_buf;
+	for (i = 0; i < sizeof(struct nvram_header); i += 4)
+		*dst++ = __raw_readl(src++);
+	for (; i < header->len && i < NVRAM_SPACE && i < size; i += 4)
+		*dst++ = readl(src++);
+
+	return 0;
+}
+
+/*
+ * On bcm47xx we need access to the NVRAM very early, so we can't use mtd
+ * subsystem to access flash. We can't even use platform device / driver to
+ * store memory offset.
+ * To handle this we provide following symbol. It's supposed to be called as
+ * soon as we get info about flash device, before any NVRAM entry is needed.
+ */
+int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
+{
+	void __iomem *iobase;
+	int err;
+
+	iobase = ioremap_nocache(base, lim);
+	if (!iobase)
+		return -ENOMEM;
+
+	err = nvram_find_and_copy(iobase, lim);
+
+	iounmap(iobase);
+
+	return err;
+}
+
+static int nvram_init(void)
+{
+#ifdef CONFIG_MTD
+	struct mtd_info *mtd;
+	struct nvram_header header;
+	size_t bytes_read;
+	int err, i;
+
+	mtd = get_mtd_device_nm("nvram");
+	if (IS_ERR(mtd))
+		return -ENODEV;
+
+	for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
+		loff_t from = mtd->size - nvram_sizes[i];
+
+		if (from < 0)
+			continue;
+
+		err = mtd_read(mtd, from, sizeof(header), &bytes_read,
+			       (uint8_t *)&header);
+		if (!err && header.magic == NVRAM_MAGIC) {
+			u8 *dst = (uint8_t *)nvram_buf;
+			size_t len = header.len;
+
+			if (header.len > NVRAM_SPACE) {
+				pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
+				       header.len, NVRAM_SPACE);
+				len = NVRAM_SPACE;
+			}
+
+			err = mtd_read(mtd, from, len, &bytes_read, dst);
+			if (err)
+				return err;
+
+			return 0;
+		}
+	}
+#endif
+
+	return -ENXIO;
+}
+
+int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len)
+{
+	char *var, *value, *end, *eq;
+	int data_left, err;
+
+	if (!name)
+		return -EINVAL;
+
+	if (!nvram_buf[0]) {
+		err = nvram_init();
+		if (err)
+			return err;
+	}
+
+	/* Look for name=value and return value */
+	var = &nvram_buf[sizeof(struct nvram_header)];
+	end = nvram_buf + sizeof(nvram_buf) - 2;
+	end[0] = '\0';
+	end[1] = '\0';
+	for (; *var; var = value + strlen(value) + 1) {
+		data_left = end - var;
+
+		eq = strnchr(var, data_left, '=');
+		if (!eq)
+			break;
+		value = eq + 1;
+		if (eq - var == strlen(name) &&
+		    strncmp(var, name, eq - var) == 0)
+			return snprintf(val, val_len, "%s", value);
+	}
+	return -ENOENT;
+}
+EXPORT_SYMBOL(bcm47xx_nvram_getenv);
+
+int bcm47xx_nvram_gpio_pin(const char *name)
+{
+	int i, err;
+	char nvram_var[] = "gpioXX";
+	char buf[NVRAM_MAX_GPIO_VALUE_LEN];
+
+	/* TODO: Optimize it to don't call getenv so many times */
+	for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) {
+		err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
+		if (err <= 0)
+			continue;
+		err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf));
+		if (err <= 0)
+			continue;
+		if (!strcmp(name, buf))
+			return i;
+	}
+	return -ENOENT;
+}
+EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
+
+MODULE_LICENSE("GPLv2");