kernel: nvmem: fix "fixed-layout" & support "mac-base"

DT binding for MAC cells in fixed layout was upstream approved and
accepted. Add support for it. This can replace quite some of our
downstream hacks.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
(cherry picked from commit 61f674df4f)
This commit is contained in:
Rafał Miłecki 2023-07-13 19:39:42 +02:00
parent e465592155
commit b649b0bf71
2 changed files with 133 additions and 0 deletions

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@ -0,0 +1,40 @@
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Thu, 13 Jul 2023 17:30:59 +0200
Subject: [PATCH] nvmem: core: fix support for fixed cells NVMEM layout
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Returning -EPROBE_DEFER for "fixed-layout" makes nvmem_register() always
fail (that layout is supported internally with no external module). That
makes callers (e.g. mtd_nvmem_add()) fail as well and prevents booting
on devices with "fixed-layout" in DT.
Add a quick workaround for it.
Fixes: 6468a6f45148 ("nvmem: core: handle the absence of expected layouts")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -794,6 +794,19 @@ static struct nvmem_layout *nvmem_layout
return NULL;
/*
+ * We should return -EPROBE_DEFER only when layout driver is expected to
+ * become available later. Otherwise NVMEM will never probe successfully
+ * for unsupported layouts. There is no known solution for that right
+ * now.
+ *
+ * This problem also affects "fixed-layout". It's supported in NVMEM
+ * core code so there never will be layout for it. We shouldn't return
+ * -EPROBE_DEFER in such case. Add a quick workaround for that.
+ */
+ if (of_device_is_compatible(layout_np, "fixed-layout"))
+ return NULL;
+
+ /*
* In case the nvmem device was built-in while the layout was built as a
* module, we shall manually request the layout driver loading otherwise
* we'll never have any match.

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@ -0,0 +1,93 @@
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Thu, 13 Jul 2023 18:29:19 +0200
Subject: [PATCH] nvmem: core: support "mac-base" fixed layout cells
Fixed layout binding allows specifying "mac-base" NVMEM cells. It's used
for base MAC address (that can be used for calculating relative
addresses). It can be stored in a raw binary format or as an ASCII
string.
---
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
menuconfig NVMEM
bool "NVMEM Support"
+ select GENERIC_NET_UTILS
help
Support for NVMEM(Non Volatile Memory) devices like EEPROM, EFUSES...
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -7,9 +7,11 @@
*/
#include <linux/device.h>
+#include <linux/etherdevice.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/idr.h>
+#include <linux/if_ether.h>
#include <linux/init.h>
#include <linux/kref.h>
#include <linux/module.h>
@@ -696,6 +698,37 @@ static int nvmem_validate_keepouts(struc
return 0;
}
+static int nvmem_mac_base_raw_read(void *context, const char *id, int index, unsigned int offset,
+ void *buf, size_t bytes)
+{
+ if (WARN_ON(bytes != ETH_ALEN))
+ return -EINVAL;
+
+ if (index)
+ eth_addr_add(buf, index);
+
+ return 0;
+}
+
+static int nvmem_mac_base_ascii_read(void *context, const char *id, int index, unsigned int offset,
+ void *buf, size_t bytes)
+{
+ u8 mac[ETH_ALEN];
+
+ if (WARN_ON(bytes != 3 * ETH_ALEN - 1))
+ 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 nvmem_add_cells_from_dt(struct nvmem_device *nvmem, struct device_node *np)
{
struct nvmem_layout *layout = nvmem->layout;
@@ -731,6 +764,20 @@ static int nvmem_add_cells_from_dt(struc
if (layout && layout->fixup_cell_info)
layout->fixup_cell_info(nvmem, layout, &info);
+ if (of_device_is_compatible(np, "fixed-layout")) {
+ if (of_device_is_compatible(child, "mac-base")) {
+ if (info.bytes == 6) {
+ info.raw_len = info.bytes;
+ info.bytes = ETH_ALEN;
+ info.read_post_process = nvmem_mac_base_raw_read;
+ } else if (info.bytes == 3 * ETH_ALEN - 1) {
+ info.raw_len = info.bytes;
+ info.bytes = ETH_ALEN;
+ info.read_post_process = nvmem_mac_base_ascii_read;
+ }
+ }
+ }
+
ret = nvmem_add_one_cell(nvmem, &info);
kfree(info.name);
if (ret) {