From 5652d1741574eb89cc02576e50ee3e348bd6dd77 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marek=20Beh=C3=BAn?= 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 Tested-by: Christian Marangi Reviewed-by: Christian Marangi Signed-off-by: David S. Miller --- 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 &&