1 files changed, 240 insertions, 0 deletions
diff --git a/drivers/firmware/broadcom/bcm47xx_nvram.c b/drivers/firmware/broadcom/bcm47xx_nvram.c
new file mode 100644
index 000000000..bd235833b
--- /dev/null
+++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
@@ -0,0 +1,240 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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>
+ */
+
+#include <linux/io.h>
+#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			0x10000
+#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 size_t nvram_len;
+static const u32 nvram_sizes[] = {0x6000, 0x8000, 0xF000, 0x10000};
+
+/**
+ * bcm47xx_nvram_is_valid - check for a valid NVRAM at specified memory
+ */
+static bool bcm47xx_nvram_is_valid(void __iomem *nvram)
+{
+	return ((struct nvram_header *)nvram)->magic == NVRAM_MAGIC;
+}
+
+/**
+ * bcm47xx_nvram_copy - copy NVRAM to internal buffer
+ */
+static void bcm47xx_nvram_copy(void __iomem *nvram_start, size_t res_size)
+{
+	struct nvram_header __iomem *header = nvram_start;
+	size_t copy_size;
+
+	copy_size = header->len;
+	if (copy_size > res_size) {
+		pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n");
+		copy_size = res_size;
+	}
+	if (copy_size >= NVRAM_SPACE) {
+		pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
+		       copy_size, NVRAM_SPACE - 1);
+		copy_size = NVRAM_SPACE - 1;
+	}
+
+	__ioread32_copy(nvram_buf, nvram_start, DIV_ROUND_UP(copy_size, 4));
+	nvram_buf[NVRAM_SPACE - 1] = '\0';
+	nvram_len = copy_size;
+}
+
+/**
+ * bcm47xx_nvram_find_and_copy - find NVRAM on flash mapping & copy it
+ */
+static int bcm47xx_nvram_find_and_copy(void __iomem *flash_start, size_t res_size)
+{
+	size_t flash_size;
+	size_t offset;
+	int i;
+
+	if (nvram_len) {
+		pr_warn("nvram already initialized\n");
+		return -EEXIST;
+	}
+
+	/* TODO: when nvram is on nand flash check for bad blocks first. */
+
+	/* Try every possible flash size and check for NVRAM at its end */
+	for (flash_size = FLASH_MIN; flash_size <= res_size; flash_size <<= 1) {
+		for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
+			offset = flash_size - nvram_sizes[i];
+			if (bcm47xx_nvram_is_valid(flash_start + offset))
+				goto found;
+		}
+	}
+
+	/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
+
+	offset = 4096;
+	if (bcm47xx_nvram_is_valid(flash_start + offset))
+		goto found;
+
+	offset = 1024;
+	if (bcm47xx_nvram_is_valid(flash_start + offset))
+		goto found;
+
+	pr_err("no nvram found\n");
+	return -ENXIO;
+
+found:
+	bcm47xx_nvram_copy(flash_start + offset, res_size - offset);
+
+	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(base, lim);
+	if (!iobase)
+		return -ENOMEM;
+
+	err = bcm47xx_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;
+
+	mtd = get_mtd_device_nm("nvram");
+	if (IS_ERR(mtd))
+		return -ENODEV;
+
+	err = mtd_read(mtd, 0, sizeof(header), &bytes_read, (uint8_t *)&header);
+	if (!err && header.magic == NVRAM_MAGIC &&
+	    header.len > sizeof(header)) {
+		nvram_len = header.len;
+		if (nvram_len >= NVRAM_SPACE) {
+			pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
+				nvram_len, NVRAM_SPACE);
+			nvram_len = NVRAM_SPACE - 1;
+		}
+
+		err = mtd_read(mtd, 0, nvram_len, &nvram_len,
+			       (u8 *)nvram_buf);
+		return err;
+	}
+#endif
+
+	return -ENXIO;
+}
+
+int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len)
+{
+	char *var, *value, *end, *eq;
+	int err;
+
+	if (!name)
+		return -EINVAL;
+
+	if (!nvram_len) {
+		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);
+	while (var < end && *var) {
+		eq = strchr(var, '=');
+		if (!eq)
+			break;
+		value = eq + 1;
+		if (eq - var == strlen(name) &&
+		    strncmp(var, name, eq - var) == 0)
+			return snprintf(val, val_len, "%s", value);
+		var = value + strlen(value) + 1;
+	}
+	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);
+
+char *bcm47xx_nvram_get_contents(size_t *nvram_size)
+{
+	int err;
+	char *nvram;
+
+	if (!nvram_len) {
+		err = nvram_init();
+		if (err)
+			return NULL;
+	}
+
+	*nvram_size = nvram_len - sizeof(struct nvram_header);
+	nvram = vmalloc(*nvram_size);
+	if (!nvram)
+		return NULL;
+	memcpy(nvram, &nvram_buf[sizeof(struct nvram_header)], *nvram_size);
+
+	return nvram;
+}
+EXPORT_SYMBOL(bcm47xx_nvram_get_contents);
+
+MODULE_LICENSE("GPL v2");