kernel: backport Broadcom NVRAM driver cleanups

Refactoring of bcm47xx_nvram driver. It's used by bcm47xx and bcm53xx.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

1 files changed, 95 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.10/800-v5.13-0002-firmware-bcm47xx_nvram-add-helper-checking-for-NVRAM.patch b/target/linux/generic/backport-5.10/800-v5.13-0002-firmware-bcm47xx_nvram-add-helper-checking-for-NVRAM.patch
new file mode 100644
index 0000000000..beef1cf675
--- /dev/null
+++ b/target/linux/generic/backport-5.10/800-v5.13-0002-firmware-bcm47xx_nvram-add-helper-checking-for-NVRAM.patch
@@ -0,0 +1,95 @@
+From 0a24b51a3264a3f942a75025ea5ff6133c8989b0 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Mon, 8 Mar 2021 10:03:17 +0100
+Subject: [PATCH] firmware: bcm47xx_nvram: add helper checking for NVRAM
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This avoids duplicating code doing casting and checking for NVRAM magic.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
+---
+ drivers/firmware/broadcom/bcm47xx_nvram.c | 30 ++++++++++++++---------
+ 1 file changed, 18 insertions(+), 12 deletions(-)
+
+diff --git a/drivers/firmware/broadcom/bcm47xx_nvram.c b/drivers/firmware/broadcom/bcm47xx_nvram.c
+index b04007adc79f..99f3ec180be6 100644
+--- a/drivers/firmware/broadcom/bcm47xx_nvram.c
++++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
+@@ -34,14 +34,20 @@ 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;
++}
++
+ 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)
++		if (bcm47xx_nvram_is_valid(end - nvram_sizes[i]))
+ 			return nvram_sizes[i];
+ 	}
+ 
+@@ -55,6 +61,7 @@ static int bcm47xx_nvram_find_and_copy(void __iomem *flash_start, size_t res_siz
+ {
+ 	struct nvram_header __iomem *header;
+ 	size_t flash_size;
++	size_t offset;
+ 	u32 size;
+ 
+ 	if (nvram_len) {
+@@ -68,31 +75,30 @@ static int bcm47xx_nvram_find_and_copy(void __iomem *flash_start, size_t res_siz
+ 		/* Windowed flash access */
+ 		size = find_nvram_size(flash_start + flash_size);
+ 		if (size) {
+-			header = (struct nvram_header *)(flash_start + flash_size - size);
++			offset = flash_size - size;
+ 			goto found;
+ 		}
+ 		flash_size <<= 1;
+ 	}
+ 
+ 	/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
+-	header = (struct nvram_header *)(flash_start + 4096);
+-	if (header->magic == NVRAM_MAGIC) {
+-		size = NVRAM_SPACE;
++
++	offset = 4096;
++	if (bcm47xx_nvram_is_valid(flash_start + offset))
+ 		goto found;
+-	}
+ 
+-	header = (struct nvram_header *)(flash_start + 1024);
+-	if (header->magic == NVRAM_MAGIC) {
+-		size = NVRAM_SPACE;
++	offset = 1024;
++	if (bcm47xx_nvram_is_valid(flash_start + offset))
+ 		goto found;
+-	}
+ 
+ 	pr_err("no nvram found\n");
+ 	return -ENXIO;
+ 
+ found:
++	header = (struct nvram_header *)(flash_start + offset);
+ 	__ioread32_copy(nvram_buf, header, sizeof(*header) / 4);
+ 	nvram_len = ((struct nvram_header *)(nvram_buf))->len;
++	size = res_size - offset;
+ 	if (nvram_len > size) {
+ 		pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n");
+ 		nvram_len = size;
+-- 
+2.26.2
+