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>
(cherry picked from commit 1c48eee5b2bcfaf9815cc9a6f6664392d17164cb)

5 files changed, 357 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/831-v5.13-0001-firmware-bcm47xx_nvram-rename-finding-function-and-i.patch b/target/linux/generic/backport-5.4/831-v5.13-0001-firmware-bcm47xx_nvram-rename-finding-function-and-i.patch
new file mode 100644
index 0000000000..19938704b7
--- /dev/null
+++ b/target/linux/generic/backport-5.4/831-v5.13-0001-firmware-bcm47xx_nvram-rename-finding-function-and-i.patch
@@ -0,0 +1,80 @@
+From fb009cbdd0693bd633f11e99526617b3d392cfad 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 10:03:16 +0100
+Subject: [PATCH] firmware: bcm47xx_nvram: rename finding function and its
+ variables
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+1. Use "bcm47xx_" function name prefix for consistency
+2. It takes flash start as argument so s/iobase/flash_start/
+3. "off" was used for finding flash end so just call it "flash_size"
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
+---
+ drivers/firmware/broadcom/bcm47xx_nvram.c | 24 ++++++++++++-----------
+ 1 file changed, 13 insertions(+), 11 deletions(-)
+
+--- a/drivers/firmware/broadcom/bcm47xx_nvram.c
++++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
+@@ -48,11 +48,13 @@ static u32 find_nvram_size(void __iomem
+ 	return 0;
+ }
+ 
+-/* Probe for NVRAM header */
+-static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
++/**
++ * 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)
+ {
+ 	struct nvram_header __iomem *header;
+-	u32 off;
++	size_t flash_size;
+ 	u32 size;
+ 
+ 	if (nvram_len) {
+@@ -61,25 +63,25 @@ static int nvram_find_and_copy(void __io
+ 	}
+ 
+ 	/* TODO: when nvram is on nand flash check for bad blocks first. */
+-	off = FLASH_MIN;
+-	while (off <= lim) {
++	flash_size = FLASH_MIN;
++	while (flash_size <= res_size) {
+ 		/* Windowed flash access */
+-		size = find_nvram_size(iobase + off);
++		size = find_nvram_size(flash_start + flash_size);
+ 		if (size) {
+-			header = (struct nvram_header *)(iobase + off - size);
++			header = (struct nvram_header *)(flash_start + flash_size - size);
+ 			goto found;
+ 		}
+-		off <<= 1;
++		flash_size <<= 1;
+ 	}
+ 
+ 	/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
+-	header = (struct nvram_header *)(iobase + 4096);
++	header = (struct nvram_header *)(flash_start + 4096);
+ 	if (header->magic == NVRAM_MAGIC) {
+ 		size = NVRAM_SPACE;
+ 		goto found;
+ 	}
+ 
+-	header = (struct nvram_header *)(iobase + 1024);
++	header = (struct nvram_header *)(flash_start + 1024);
+ 	if (header->magic == NVRAM_MAGIC) {
+ 		size = NVRAM_SPACE;
+ 		goto found;
+@@ -124,7 +126,7 @@ int bcm47xx_nvram_init_from_mem(u32 base
+ 	if (!iobase)
+ 		return -ENOMEM;
+ 
+-	err = nvram_find_and_copy(iobase, lim);
++	err = bcm47xx_nvram_find_and_copy(iobase, lim);
+ 
+ 	iounmap(iobase);
+ 
diff --git a/target/linux/generic/backport-5.4/831-v5.13-0002-firmware-bcm47xx_nvram-add-helper-checking-for-NVRAM.patch b/target/linux/generic/backport-5.4/831-v5.13-0002-firmware-bcm47xx_nvram-add-helper-checking-for-NVRAM.patch
new file mode 100644
index 0000000000..6ab072883d
--- /dev/null
+++ b/target/linux/generic/backport-5.4/831-v5.13-0002-firmware-bcm47xx_nvram-add-helper-checking-for-NVRAM.patch
@@ -0,0 +1,90 @@
+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(-)
+
+--- 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(v
+ {
+ 	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(v
+ 		/* 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;
diff --git a/target/linux/generic/backport-5.4/831-v5.13-0003-firmware-bcm47xx_nvram-extract-code-copying-NVRAM.patch b/target/linux/generic/backport-5.4/831-v5.13-0003-firmware-bcm47xx_nvram-extract-code-copying-NVRAM.patch
new file mode 100644
index 0000000000..a1351f1197
--- /dev/null
+++ b/target/linux/generic/backport-5.4/831-v5.13-0003-firmware-bcm47xx_nvram-extract-code-copying-NVRAM.patch
@@ -0,0 +1,80 @@
+From 298923cf999cecd2ef06df126f85a3d68da8c4d8 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 10:03:18 +0100
+Subject: [PATCH] firmware: bcm47xx_nvram: extract code copying NVRAM
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This simplifies function finding NVRAM. It doesn't directly deal with
+NVRAM structure anymore and is a bit smaller.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
+---
+ drivers/firmware/broadcom/bcm47xx_nvram.c | 43 +++++++++++++----------
+ 1 file changed, 25 insertions(+), 18 deletions(-)
+
+--- a/drivers/firmware/broadcom/bcm47xx_nvram.c
++++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
+@@ -55,11 +55,34 @@ static u32 find_nvram_size(void __iomem
+ }
+ 
+ /**
++ * 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)
+ {
+-	struct nvram_header __iomem *header;
+ 	size_t flash_size;
+ 	size_t offset;
+ 	u32 size;
+@@ -95,23 +118,7 @@ static int bcm47xx_nvram_find_and_copy(v
+ 	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;
+-	}
+-	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 - 1);
+-		nvram_len = NVRAM_SPACE - 1;
+-	}
+-	/* proceed reading data after header */
+-	__ioread32_copy(nvram_buf + sizeof(*header), header + 1,
+-			DIV_ROUND_UP(nvram_len, 4));
+-	nvram_buf[NVRAM_SPACE - 1] = '\0';
++	bcm47xx_nvram_copy(flash_start + offset, res_size - offset);
+ 
+ 	return 0;
+ }
diff --git a/target/linux/generic/backport-5.4/831-v5.13-0004-firmware-bcm47xx_nvram-look-for-NVRAM-with-for-inste.patch b/target/linux/generic/backport-5.4/831-v5.13-0004-firmware-bcm47xx_nvram-look-for-NVRAM-with-for-inste.patch
new file mode 100644
index 0000000000..059a13220b
--- /dev/null
+++ b/target/linux/generic/backport-5.4/831-v5.13-0004-firmware-bcm47xx_nvram-look-for-NVRAM-with-for-inste.patch
@@ -0,0 +1,37 @@
+From 98b68324f67236e8c9152976535dc1f27fb67ba8 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 10:03:19 +0100
+Subject: [PATCH] firmware: bcm47xx_nvram: look for NVRAM with for instead of
+ while
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This loop requires variable initialization, stop condition and post
+iteration increment. It's pretty much a for loop definition.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
+---
+ drivers/firmware/broadcom/bcm47xx_nvram.c | 4 +---
+ 1 file changed, 1 insertion(+), 3 deletions(-)
+
+--- a/drivers/firmware/broadcom/bcm47xx_nvram.c
++++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
+@@ -93,15 +93,13 @@ static int bcm47xx_nvram_find_and_copy(v
+ 	}
+ 
+ 	/* TODO: when nvram is on nand flash check for bad blocks first. */
+-	flash_size = FLASH_MIN;
+-	while (flash_size <= res_size) {
++	for (flash_size = FLASH_MIN; flash_size <= res_size; flash_size <<= 1) {
+ 		/* Windowed flash access */
+ 		size = find_nvram_size(flash_start + flash_size);
+ 		if (size) {
+ 			offset = flash_size - size;
+ 			goto found;
+ 		}
+-		flash_size <<= 1;
+ 	}
+ 
+ 	/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
diff --git a/target/linux/generic/backport-5.4/831-v5.13-0005-firmware-bcm47xx_nvram-inline-code-checking-NVRAM-si.patch b/target/linux/generic/backport-5.4/831-v5.13-0005-firmware-bcm47xx_nvram-inline-code-checking-NVRAM-si.patch
new file mode 100644
index 0000000000..21d250049e
--- /dev/null
+++ b/target/linux/generic/backport-5.4/831-v5.13-0005-firmware-bcm47xx_nvram-inline-code-checking-NVRAM-si.patch
@@ -0,0 +1,70 @@
+From f52da4ccfec9192e17f5c16260dfdd6d3ea76f65 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 10:03:20 +0100
+Subject: [PATCH] firmware: bcm47xx_nvram: inline code checking NVRAM size
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Separated function was not improving code quality much (or at all).
+Moreover it expected possible flash end address as argument and it was
+returning NVRAM size.
+
+The new code always operates on offsets which means less logic and less
+calculations.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
+---
+ drivers/firmware/broadcom/bcm47xx_nvram.c | 25 +++++++----------------
+ 1 file changed, 7 insertions(+), 18 deletions(-)
+
+--- a/drivers/firmware/broadcom/bcm47xx_nvram.c
++++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
+@@ -42,18 +42,6 @@ static bool bcm47xx_nvram_is_valid(void
+ 	return ((struct nvram_header *)nvram)->magic == NVRAM_MAGIC;
+ }
+ 
+-static u32 find_nvram_size(void __iomem *end)
+-{
+-	int i;
+-
+-	for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
+-		if (bcm47xx_nvram_is_valid(end - nvram_sizes[i]))
+-			return nvram_sizes[i];
+-	}
+-
+-	return 0;
+-}
+-
+ /**
+  * bcm47xx_nvram_copy - copy NVRAM to internal buffer
+  */
+@@ -85,7 +73,7 @@ static int bcm47xx_nvram_find_and_copy(v
+ {
+ 	size_t flash_size;
+ 	size_t offset;
+-	u32 size;
++	int i;
+ 
+ 	if (nvram_len) {
+ 		pr_warn("nvram already initialized\n");
+@@ -93,12 +81,13 @@ static int bcm47xx_nvram_find_and_copy(v
+ 	}
+ 
+ 	/* 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) {
+-		/* Windowed flash access */
+-		size = find_nvram_size(flash_start + flash_size);
+-		if (size) {
+-			offset = flash_size - size;
+-			goto found;
++		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;
+ 		}
+ 	}
+