bcm53xx: add the latest fix version of brcm_nvram

It was just sent for upstream.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
(cherry picked from commit 943bd3c9f6244c928cd168302d638a6a218fd4e6)

1 files changed, 256 insertions, 0 deletions

diff --git a/target/linux/bcm53xx/patches-5.15/181-nvmem-brcm_nvram-store-a-copy-of-NVRAM-content.patch b/target/linux/bcm53xx/patches-5.15/181-nvmem-brcm_nvram-store-a-copy-of-NVRAM-content.patch
new file mode 100644
index 0000000000..cceb3635ac
--- /dev/null
+++ b/target/linux/bcm53xx/patches-5.15/181-nvmem-brcm_nvram-store-a-copy-of-NVRAM-content.patch
@@ -0,0 +1,256 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Thu, 14 Sep 2023 07:59:09 +0200
+Subject: [PATCH] nvmem: brcm_nvram: store a copy of NVRAM content
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This driver uses MMIO access for reading NVRAM from a flash device.
+Underneath there is a flash controller that reads data and provides
+mapping window.
+
+Using MMIO interface affects controller configuration and may break real
+controller driver. It was reported by multiple users of devices with
+NVRAM stored on NAND.
+
+Modify driver to read & cache NVRAM content during init and use that
+copy to provide NVMEM data when requested. On NAND flashes due to their
+alignment NVRAM partitions can be quite big (1 MiB and more) while
+actual NVRAM content stays quite small (usually 16 to 32 KiB). To avoid
+allocating so much memory check for actual data length.
+
+Link: https://lore.kernel.org/linux-mtd/CACna6rwf3_9QVjYcM+847biTX=K0EoWXuXcSMkJO1Vy_5vmVqA@mail.gmail.com/
+Fixes: 3fef9ed0627a ("nvmem: brcm_nvram: new driver exposing Broadcom's NVRAM")
+Cc: Arınç ÜNAL <arinc.unal@arinc9.com>
+Cc: Florian Fainelli <florian.fainelli@broadcom.com>
+Cc: Scott Branden <scott.branden@broadcom.com>
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
+---
+ drivers/nvmem/brcm_nvram.c | 134 ++++++++++++++++++++++++++-----------
+ 1 file changed, 94 insertions(+), 40 deletions(-)
+
+--- a/drivers/nvmem/brcm_nvram.c
++++ b/drivers/nvmem/brcm_nvram.c
+@@ -17,9 +17,23 @@
+ 
+ #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 underlaying 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;
+ };
+@@ -36,10 +50,47 @@ static int brcm_nvram_read(void *context
+ 			   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);
+ 
+-	while (bytes--)
+-		*dst++ = readb(priv->base + offset++);
++	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;
+ }
+@@ -67,8 +118,13 @@ static int brcm_nvram_add_cells(struct b
+ 				size_t len)
+ {
+ 	struct device *dev = priv->dev;
+-	char *var, *value, *eq;
++	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);
+@@ -78,67 +134,68 @@ static int brcm_nvram_add_cells(struct b
+ 	}
+ 
+ 	priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
+-	if (!priv->cells)
+-		return -ENOMEM;
++	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 = devm_kstrdup(dev, var, GFP_KERNEL);
+-		if (!priv->cells[idx].name)
+-			return -ENOMEM;
++		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(var, "et0macaddr") ||
+-		    !strcmp(var, "et1macaddr") ||
+-		    !strcmp(var, "et2macaddr")) {
++		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;
+ 		}
+ 	}
+ 
+-	return 0;
++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;
+-	struct brcm_nvram_header header;
+-	uint8_t *data;
+ 	size_t len;
+ 	int err;
+ 
+-	memcpy_fromio(&header, priv->base, sizeof(header));
+-
+-	if (memcmp(header.magic, NVRAM_MAGIC, 4)) {
++	if (memcmp(header->magic, NVRAM_MAGIC, 4)) {
+ 		dev_err(dev, "Invalid NVRAM magic\n");
+ 		return -EINVAL;
+ 	}
+ 
+-	len = le32_to_cpu(header.len);
+-
+-	data = kzalloc(len, GFP_KERNEL);
+-	if (!data)
+-		return -ENOMEM;
+-
+-	memcpy_fromio(data, priv->base, len);
+-	data[len - 1] = '\0';
+-
+-	err = brcm_nvram_add_cells(priv, data, len);
+-	if (err) {
+-		dev_err(dev, "Failed to add cells: %d\n", err);
+-		return err;
++	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;
+ 	}
+ 
+-	kfree(data);
++	err = brcm_nvram_add_cells(priv, priv->data, len);
++	if (err)
++		dev_err(dev, "Failed to add cells: %d\n", err);
+ 
+ 	return 0;
+ }
+@@ -150,7 +207,6 @@ static int brcm_nvram_probe(struct platf
+ 		.reg_read = brcm_nvram_read,
+ 	};
+ 	struct device *dev = &pdev->dev;
+-	struct resource *res;
+ 	struct brcm_nvram *priv;
+ 	int err;
+ 
+@@ -159,21 +215,19 @@ static int brcm_nvram_probe(struct platf
+ 		return -ENOMEM;
+ 	priv->dev = dev;
+ 
+-	priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &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;
+ 
+-	bcm47xx_nvram_init_from_iomem(priv->base, resource_size(res));
+-
+ 	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));
+ }