From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8A375DDC7 for ; Tue, 3 Oct 2023 15:22:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA801C433C7; Tue, 3 Oct 2023 15:22:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696346546; bh=GATpp7gLk+9vH4S+ZsqxKEXorMVjpzl17S6e9IMF6Ug=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pF3Rw9+BWoA4AVvAYwySQBDtgOoPjaC3ODX2YvtSeXexKph9UTnOh67F/rOXiNKcu Rr8O8rOryG+loxf9SkMsrQn9UZd6kcOjzxNt+JhL4NMJpZbMbzcH/SOuyObrYEtbfP hhfhk2m/dVqjAqUpGBGndaFQQrFDO9q/2gEQmKga67JXPYRjartMQ3GW8a5DcF+9Ga J1fwawlMj+ePJPr8lw4fb0uOVnJ0c4zE2NmDrspjjz3nHUr01PivBztSIZBBcXwkc3 kOWtyJHG7cnFS40UvaGEUJ9NUbraApDPg7ipkcl/5eYdLpKKsEn2ebTq2JcOdZJVpt SdRiS2dqR01ig== Date: Tue, 3 Oct 2023 17:22:22 +0200 From: Simon Horman To: Marek =?utf-8?B?QmVow7pu?= Cc: Christian Marangi , "David S. Miller" , Paolo Abeni , netdev@vger.kernel.org Subject: Re: [PATCH net 1/2] net: dsa: qca8k: fix regmap bulk read/write methods on big endian systems Message-ID: References: <20231002104612.21898-1-kabel@kernel.org> <20231002104612.21898-2-kabel@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20231002104612.21898-2-kabel@kernel.org> On Mon, Oct 02, 2023 at 12:46:11PM +0200, Marek Behún wrote: > 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 correnspond to the low 16-bits, but it nit: correspond > 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 > --- > drivers/net/dsa/qca/qca8k-8xxx.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c > index de1dc22cf683..d2df30640269 100644 > --- a/drivers/net/dsa/qca/qca8k-8xxx.c > +++ b/drivers/net/dsa/qca/qca8k-8xxx.c > @@ -505,8 +505,8 @@ qca8k_bulk_read(void *ctx, const void *reg_buf, size_t reg_len, > 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)) > @@ -527,8 +527,8 @@ qca8k_bulk_gather_write(void *ctx, const void *reg_buf, size_t reg_len, > 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 && > -- > 2.41.0 > >