From a18378409fee1cac0f0c58a4770ff557b498c778 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Fri, 1 Sep 2023 10:44:26 +0200
Subject: [PATCH] nvmem: brcm_nvram: store a copy of NVRAM content
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
 drivers/nvmem/brcm_nvram.c | 54 +++++++++++++++++++-------------------
 1 file changed, 27 insertions(+), 27 deletions(-)

--- a/drivers/nvmem/brcm_nvram.c
+++ b/drivers/nvmem/brcm_nvram.c
@@ -19,7 +19,7 @@
 
 struct brcm_nvram {
 	struct device *dev;
-	void __iomem *base;
+	uint8_t *data;
 	struct nvmem_cell_info *cells;
 	int ncells;
 };
@@ -36,10 +36,8 @@ static int brcm_nvram_read(void *context
 			   size_t bytes)
 {
 	struct brcm_nvram *priv = context;
-	u8 *dst = val;
 
-	while (bytes--)
-		*dst++ = readb(priv->base + offset++);
+	memcpy(val, priv->data + offset, bytes);
 
 	return 0;
 }
@@ -110,35 +108,27 @@ static int brcm_nvram_add_cells(struct b
 
 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;
+	uint8_t tmp;
 	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);
+	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';
+	tmp = priv->data[len - 1];
+	priv->data[len - 1] = '\0';
 
-	err = brcm_nvram_add_cells(priv, data, len);
-	if (err) {
+	err = brcm_nvram_add_cells(priv, priv->data, len);
+	if (err)
 		dev_err(dev, "Failed to add cells: %d\n", err);
-		return err;
-	}
 
-	kfree(data);
+	priv->data[len - 1] = tmp;
 
 	return 0;
 }
@@ -150,8 +140,10 @@ static int brcm_nvram_probe(struct platf
 		.reg_read = brcm_nvram_read,
 	};
 	struct device *dev = &pdev->dev;
-	struct resource *res;
 	struct brcm_nvram *priv;
+	struct resource *res;
+	void __iomem *base;
+	size_t size;
 	int err;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
@@ -159,21 +151,29 @@ 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);
+	base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	size = resource_size(res);
+
+	priv->data = kzalloc(size, GFP_KERNEL);
+	if (!priv->data)
+		return -ENOMEM;
+
+	memcpy_fromio(priv->data, base, size);
 
 	err = brcm_nvram_parse(priv);
 	if (err)
 		return err;
 
-	bcm47xx_nvram_init_from_iomem(priv->base, resource_size(res));
+	bcm47xx_nvram_init_from_iomem(base, size);
 
 	config.dev = dev;
 	config.cells = priv->cells;
 	config.ncells = priv->ncells;
 	config.priv = priv;
-	config.size = resource_size(res);
+	config.size = size;
 
 	return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
 }