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From 5652d1741574eb89cc02576e50ee3e348bd6dd77 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org>
Date: Wed, 4 Oct 2023 11:19:03 +0200
Subject: [PATCH 1/2] net: dsa: qca8k: fix regmap bulk read/write methods on
big endian systems
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Commit c766e077d927 ("net: dsa: qca8k: convert to regmap read/write
API") introduced bulk read/write methods to qca8k's regmap.
The regmap bulk read/write methods get the register address in a buffer
passed as a void pointer parameter (the same buffer contains also the
read/written values). The register address occupies only as many bytes
as it requires at the beginning of this buffer. For example if the
.reg_bits member in regmap_config is 16 (as is the case for this
driver), the register address occupies only the first 2 bytes in this
buffer, so it can be cast to u16.
But the original commit implementing these bulk read/write methods cast
the buffer to u32:
u32 reg = *(u32 *)reg_buf & U16_MAX;
taking the first 4 bytes. This works on little endian systems where the
first 2 bytes of the buffer correspond to the low 16-bits, but it
obviously cannot work on big endian systems.
Fix this by casting the beginning of the buffer to u16 as
u32 reg = *(u16 *)reg_buf;
Fixes: c766e077d927 ("net: dsa: qca8k: convert to regmap read/write API")
Signed-off-by: Marek Behún <kabel@kernel.org>
Tested-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/dsa/qca/qca8k-8xxx.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
@@ -504,8 +504,8 @@ qca8k_bulk_read(void *ctx, const void *r
void *val_buf, size_t val_len)
{
int i, count = val_len / sizeof(u32), ret;
- u32 reg = *(u32 *)reg_buf & U16_MAX;
struct qca8k_priv *priv = ctx;
+ u32 reg = *(u16 *)reg_buf;
if (priv->mgmt_master &&
!qca8k_read_eth(priv, reg, val_buf, val_len))
@@ -526,8 +526,8 @@ qca8k_bulk_gather_write(void *ctx, const
const void *val_buf, size_t val_len)
{
int i, count = val_len / sizeof(u32), ret;
- u32 reg = *(u32 *)reg_buf & U16_MAX;
struct qca8k_priv *priv = ctx;
+ u32 reg = *(u16 *)reg_buf;
u32 *val = (u32 *)val_buf;
if (priv->mgmt_master &&
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