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Message-ID: <20231110195628.GA673918@kernel.org>
Date: Fri, 10 Nov 2023 19:57:02 +0000
From: Simon Horman <horms@...nel.org>
To: Christian Marangi <ansuelsmth@...il.com>
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>, Andrew Lunn <andrew@...n.ch>,
Heiner Kallweit <hkallweit1@...il.com>,
Russell King <linux@...linux.org.uk>,
Robert Marko <robimarko@...il.com>,
Vladimir Oltean <vladimir.oltean@....com>, netdev@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [net-next RFC PATCH v6 3/4] net: phy: aquantia: add firmware
load support
On Thu, Nov 09, 2023 at 01:32:52PM +0100, Christian Marangi wrote:
> From: Robert Marko <robimarko@...il.com>
>
> Aquantia PHY-s require firmware to be loaded before they start operating.
> It can be automatically loaded in case when there is a SPI-NOR connected
> to Aquantia PHY-s or can be loaded from the host via MDIO.
>
> This patch adds support for loading the firmware via MDIO as in most cases
> there is no SPI-NOR being used to save on cost.
> Firmware loading code itself is ported from mainline U-boot with cleanups.
>
> The firmware has mixed values both in big and little endian.
> PHY core itself is big-endian but it expects values to be in little-endian.
> The firmware is little-endian but CRC-16 value for it is stored at the end
> of firmware in big-endian.
>
> It seems the PHY does the conversion internally from firmware that is
> little-endian to the PHY that is big-endian on using the mailbox
> but mailbox returns a big-endian CRC-16 to verify the written data
> integrity.
>
> Co-developed-by: Christian Marangi <ansuelsmth@...il.com>
> Signed-off-by: Robert Marko <robimarko@...il.com>
> Signed-off-by: Christian Marangi <ansuelsmth@...il.com>
Hi Christian and Robert,
thanks for your patch-set.
I spotted some minor endien issues which I have highlighted below.
...
> +/* load data into the phy's memory */
> +static int aqr_fw_load_memory(struct phy_device *phydev, u32 addr,
> + const u8 *data, size_t len)
> +{
> + u16 crc = 0, up_crc;
> + size_t pos;
> +
> + /* PHY expect addr in LE */
> + addr = cpu_to_le32(addr);
The type of addr is host byte-order,
but here it is assigned a little-endian value.
Flagged by Sparse.
> +
> + phy_write_mmd(phydev, MDIO_MMD_VEND1,
> + VEND1_GLOBAL_MAILBOX_INTERFACE1,
> + VEND1_GLOBAL_MAILBOX_INTERFACE1_CRC_RESET);
> + phy_write_mmd(phydev, MDIO_MMD_VEND1,
> + VEND1_GLOBAL_MAILBOX_INTERFACE3,
> + VEND1_GLOBAL_MAILBOX_INTERFACE3_MSW_ADDR(addr));
VEND1_GLOBAL_MAILBOX_INTERFACE3_MSW_ADDR() performs a bit-shift on addr,
and applies a mask which is in host-byte order.
But, as highlighted above, addr is a little-endian value.
This does not seem right.
This is all hidden by a cast in VEND1_GLOBAL_MAILBOX_INTERFACE3_MSW_ADDR()
This seems dangerous to me.
> + phy_write_mmd(phydev, MDIO_MMD_VEND1,
> + VEND1_GLOBAL_MAILBOX_INTERFACE4,
> + VEND1_GLOBAL_MAILBOX_INTERFACE4_LSW_ADDR(addr));
There seem to be similar issues with the use of addr here.
> +
> + /* We assume and enforce the size to be word aligned.
> + * If a firmware that is not word aligned is found, please report upstream.
> + */
> + for (pos = 0; pos < len; pos += sizeof(u32)) {
> + u32 word = get_unaligned((const u32 *)(data + pos));
> +
> + phy_write_mmd(phydev, MDIO_MMD_VEND1, VEND1_GLOBAL_MAILBOX_INTERFACE5,
> + VEND1_GLOBAL_MAILBOX_INTERFACE5_MSW_DATA(word));
> + phy_write_mmd(phydev, MDIO_MMD_VEND1, VEND1_GLOBAL_MAILBOX_INTERFACE6,
> + VEND1_GLOBAL_MAILBOX_INTERFACE6_LSW_DATA(word));
> +
> + phy_write_mmd(phydev, MDIO_MMD_VEND1, VEND1_GLOBAL_MAILBOX_INTERFACE1,
> + VEND1_GLOBAL_MAILBOX_INTERFACE1_EXECUTE |
> + VEND1_GLOBAL_MAILBOX_INTERFACE1_WRITE);
> +
> + /* calculate CRC as we load data to the mailbox.
> + * We convert word to big-endiang as PHY is BE and mailbox will
> + * return a BE CRC.
> + */
> + word = cpu_to_be32(word);
Similarly here, Sparse flags that a little-endian value is assigned to a
host byte-order variable.
> + crc = crc_ccitt_false(crc, (u8 *)&word, sizeof(word));
> + }
...
pw-bot: changes-requested
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