1 files changed, 190 insertions, 10 deletions

diff --git a/drivers/nvmem/brcm_nvram.c b/drivers/nvmem/brcm_nvram.c
index bd2ecaaf4585..b4cf245fb246 100644
--- a/drivers/nvmem/brcm_nvram.c
+++ b/drivers/nvmem/brcm_nvram.c
@@ -3,25 +3,199 @@
  * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
  */
 
+#include <linux/bcm47xx_nvram.h>
+#include <linux/etherdevice.h>
+#include <linux/if_ether.h>
 #include <linux/io.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
+#include <linux/nvmem-consumer.h>
 #include <linux/nvmem-provider.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/slab.h>
 
+#define NVRAM_MAGIC			"FLSH"
+
+/**
+ * struct brcm_nvram - driver state internal struct
+ *
+ * @dev:		NVMEM device pointer
+ * @nvmem_size:		Size of the whole space available for NVRAM
+ * @data:		NVRAM data copy stored to avoid poking underlying flash controller
+ * @data_len:		NVRAM data size
+ * @padding_byte:	Padding value used to fill remaining space
+ * @cells:		Array of discovered NVMEM cells
+ * @ncells:		Number of elements in cells
+ */
 struct brcm_nvram {
 	struct device *dev;
-	void __iomem *base;
+	size_t nvmem_size;
+	uint8_t *data;
+	size_t data_len;
+	uint8_t padding_byte;
+	struct nvmem_cell_info *cells;
+	int ncells;
+};
+
+struct brcm_nvram_header {
+	char magic[4];
+	__le32 len;
+	__le32 crc_ver_init;	/* 0:7 crc, 8:15 ver, 16:31 sdram_init */
+	__le32 config_refresh;	/* 0:15 sdram_config, 16:31 sdram_refresh */
+	__le32 config_ncdl;	/* ncdl values for memc */
 };
 
 static int brcm_nvram_read(void *context, unsigned int offset, void *val,
 			   size_t bytes)
 {
 	struct brcm_nvram *priv = context;
-	u8 *dst = val;
+	size_t to_copy;
+
+	if (offset + bytes > priv->data_len)
+		to_copy = max_t(ssize_t, (ssize_t)priv->data_len - offset, 0);
+	else
+		to_copy = bytes;
+
+	memcpy(val, priv->data + offset, to_copy);
+
+	memset((uint8_t *)val + to_copy, priv->padding_byte, bytes - to_copy);
+
+	return 0;
+}
+
+static int brcm_nvram_copy_data(struct brcm_nvram *priv, struct platform_device *pdev)
+{
+	struct resource *res;
+	void __iomem *base;
+
+	base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	priv->nvmem_size = resource_size(res);
+
+	priv->padding_byte = readb(base + priv->nvmem_size - 1);
+	for (priv->data_len = priv->nvmem_size;
+	     priv->data_len;
+	     priv->data_len--) {
+		if (readb(base + priv->data_len - 1) != priv->padding_byte)
+			break;
+	}
+	WARN(priv->data_len > SZ_128K, "Unexpected (big) NVRAM size: %zu B\n", priv->data_len);
+
+	priv->data = devm_kzalloc(priv->dev, priv->data_len, GFP_KERNEL);
+	if (!priv->data)
+		return -ENOMEM;
+
+	memcpy_fromio(priv->data, base, priv->data_len);
+
+	bcm47xx_nvram_init_from_iomem(base, priv->data_len);
+
+	return 0;
+}
 
-	while (bytes--)
-		*dst++ = readb(priv->base + offset++);
+static int brcm_nvram_read_post_process_macaddr(void *context, const char *id, int index,
+						unsigned int offset, void *buf, size_t bytes)
+{
+	u8 mac[ETH_ALEN];
+
+	if (bytes != MAC_ADDR_STR_LEN)
+		return -EINVAL;
+
+	if (!mac_pton(buf, mac))
+		return -EINVAL;
+
+	if (index)
+		eth_addr_add(mac, index);
+
+	ether_addr_copy(buf, mac);
+
+	return 0;
+}
+
+static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data,
+				size_t len)
+{
+	struct device *dev = priv->dev;
+	char *var, *value;
+	uint8_t tmp;
+	int idx;
+	int err = 0;
+
+	tmp = priv->data[len - 1];
+	priv->data[len - 1] = '\0';
+
+	priv->ncells = 0;
+	for (var = data + sizeof(struct brcm_nvram_header);
+	     var < (char *)data + len && *var;
+	     var += strlen(var) + 1) {
+		priv->ncells++;
+	}
+
+	priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
+	if (!priv->cells) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	for (var = data + sizeof(struct brcm_nvram_header), idx = 0;
+	     var < (char *)data + len && *var;
+	     var = value + strlen(value) + 1, idx++) {
+		char *eq, *name;
+
+		eq = strchr(var, '=');
+		if (!eq)
+			break;
+		*eq = '\0';
+		name = devm_kstrdup(dev, var, GFP_KERNEL);
+		*eq = '=';
+		if (!name) {
+			err = -ENOMEM;
+			goto out;
+		}
+		value = eq + 1;
+
+		priv->cells[idx].name = name;
+		priv->cells[idx].offset = value - (char *)data;
+		priv->cells[idx].bytes = strlen(value);
+		priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
+		if (!strcmp(name, "et0macaddr") ||
+		    !strcmp(name, "et1macaddr") ||
+		    !strcmp(name, "et2macaddr")) {
+			priv->cells[idx].raw_len = strlen(value);
+			priv->cells[idx].bytes = ETH_ALEN;
+			priv->cells[idx].read_post_process = brcm_nvram_read_post_process_macaddr;
+		}
+	}
+
+out:
+	priv->data[len - 1] = tmp;
+	return err;
+}
+
+static int brcm_nvram_parse(struct brcm_nvram *priv)
+{
+	struct brcm_nvram_header *header = (struct brcm_nvram_header *)priv->data;
+	struct device *dev = priv->dev;
+	size_t len;
+	int err;
+
+	if (memcmp(header->magic, NVRAM_MAGIC, 4)) {
+		dev_err(dev, "Invalid NVRAM magic\n");
+		return -EINVAL;
+	}
+
+	len = le32_to_cpu(header->len);
+	if (len > priv->nvmem_size) {
+		dev_err(dev, "NVRAM length (%zd) exceeds mapped size (%zd)\n", len,
+			priv->nvmem_size);
+		return -EINVAL;
+	}
+
+	err = brcm_nvram_add_cells(priv, priv->data, len);
+	if (err)
+		dev_err(dev, "Failed to add cells: %d\n", err);
 
 	return 0;
 }
@@ -33,22 +207,27 @@ static int brcm_nvram_probe(struct platform_device *pdev)
 		.reg_read = brcm_nvram_read,
 	};
 	struct device *dev = &pdev->dev;
-	struct resource *res;
 	struct brcm_nvram *priv;
+	int err;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 	priv->dev = dev;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	priv->base = devm_ioremap_resource(dev, res);
-	if (IS_ERR(priv->base))
-		return PTR_ERR(priv->base);
+	err = brcm_nvram_copy_data(priv, pdev);
+	if (err)
+		return err;
+
+	err = brcm_nvram_parse(priv);
+	if (err)
+		return err;
 
 	config.dev = dev;
+	config.cells = priv->cells;
+	config.ncells = priv->ncells;
 	config.priv = priv;
-	config.size = resource_size(res);
+	config.size = priv->nvmem_size;
 
 	return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
 }
@@ -74,5 +253,6 @@ static int __init brcm_nvram_init(void)
 subsys_initcall_sync(brcm_nvram_init);
 
 MODULE_AUTHOR("Rafał Miłecki");
+MODULE_DESCRIPTION("Broadcom I/O-mapped NVRAM support driver");
 MODULE_LICENSE("GPL");
 MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table);