Commit 194ef9d0 authored Sep 13, 2024 by Vladimir Oltean Committed by Paolo Abeni Sep 19, 2024

net: phy: aquantia: fix -ETIMEDOUT PHY probe failure when firmware not present

The author of the blamed commit apparently did not notice something
about aqr_wait_reset_complete(): it polls the exact same register -
MDIO_MMD_VEND1:VEND1_GLOBAL_FW_ID - as aqr_firmware_load().

Thus, the entire logic after the introduction of aqr_wait_reset_complete() is
now completely side-stepped, because if aqr_wait_reset_complete()
succeeds, MDIO_MMD_VEND1:VEND1_GLOBAL_FW_ID could have only been a
non-zero value. The handling of the case where the register reads as 0
is dead code, due to the previous -ETIMEDOUT having stopped execution
and returning a fatal error to the caller. We never attempt to load
new firmware if no firmware is present.

Based on static code analysis, I guess we should simply introduce a
switch/case statement based on the return code from aqr_wait_reset_complete(),
to determine whether to load firmware or not. I am not intending to
change the procedure through which the driver determines whether to load
firmware or not, as I am unaware of alternative possibilities.

At the same time, Russell King suggests that if aqr_wait_reset_complete()
is expected to return -ETIMEDOUT as part of normal operation and not
just catastrophic failure, the use of phy_read_mmd_poll_timeout() is
improper, since that has an embedded print inside. Just open-code a
call to read_poll_timeout() to avoid printing -ETIMEDOUT, but continue
printing actual read errors from the MDIO bus.

Fixes: ad649a1f ("net: phy: aquantia: wait for FW reset before checking the vendor ID")
Reported-by: Clark Wang <xiaoning.wang@nxp.com>
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Closes: https://lore.kernel.org/netdev/8ac00a45-ac61-41b4-9f74-d18157b8b6bf@nvidia.com/

Reported-by: Hans-Frieder Vogt <hfdevel@gmx.net>
Closes: https://lore.kernel.org/netdev/c7c1a3ae-be97-4929-8d89-04c8aa870209@gmx.net/

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Tested-by: Hans-Frieder Vogt <hfdevel@gmx.net>
Link: https://patch.msgid.link/20240913121230.2620122-1-vladimir.oltean@nxp.com

Signed-off-by: Paolo Abeni <pabeni@redhat.com>

parent 94106455

drivers/net/phy/aquantia/aquantia_firmware.c

+24 −18

Original line number	Diff line number	Diff line
		@@ -353,26 +353,32 @@ int aqr_firmware_load(struct phy_device *phydev)
		{
		int ret;

		/* Check if the firmware is not already loaded by polling
		* the current version returned by the PHY.
		*/
		ret = aqr_wait_reset_complete(phydev);
		if (ret)
		return ret;

		/* Check if the firmware is not already loaded by pooling
		* the current version returned by the PHY. If 0 is returned,
		* no firmware is loaded.
		switch (ret) {
		case 0:
		/* Some firmware is loaded => do nothing */
		return 0;
		case -ETIMEDOUT:
		/* VEND1_GLOBAL_FW_ID still reads 0 after 2 seconds of polling.
		* We don't have full confidence that no firmware is loaded (in
		* theory it might just not have loaded yet), but we will
		* assume that, and load a new image.
		*/
		ret = phy_read_mmd(phydev, MDIO_MMD_VEND1, VEND1_GLOBAL_FW_ID);
		if (ret > 0)
		goto exit;

		ret = aqr_firmware_load_nvmem(phydev);
		if (!ret)
		goto exit;
		return ret;

		ret = aqr_firmware_load_fs(phydev);
		if (ret)
		return ret;
		break;
		default:
		/* PHY read error, propagate it to the caller */
		return ret;
		}

		exit:
		return 0;
		}

drivers/net/phy/aquantia/aquantia_main.c

+15 −4

Original line number	Diff line number	Diff line
		@@ -435,6 +435,9 @@ static int aqr107_set_tunable(struct phy_device *phydev,
		}
		}

		#define AQR_FW_WAIT_SLEEP_US 20000
		#define AQR_FW_WAIT_TIMEOUT_US 2000000

		/* If we configure settings whilst firmware is still initializing the chip,
		* then these settings may be overwritten. Therefore make sure chip
		* initialization has completed. Use presence of the firmware ID as
		@@ -444,11 +447,19 @@ static int aqr107_set_tunable(struct phy_device *phydev,
		*/
		int aqr_wait_reset_complete(struct phy_device *phydev)
		{
		int val;
		int ret, val;

		ret = read_poll_timeout(phy_read_mmd, val, val != 0,
		AQR_FW_WAIT_SLEEP_US, AQR_FW_WAIT_TIMEOUT_US,
		false, phydev, MDIO_MMD_VEND1,
		VEND1_GLOBAL_FW_ID);
		if (val < 0) {
		phydev_err(phydev, "Failed to read VEND1_GLOBAL_FW_ID: %pe\n",
		ERR_PTR(val));
		return val;
		}

		return phy_read_mmd_poll_timeout(phydev, MDIO_MMD_VEND1,
		VEND1_GLOBAL_FW_ID, val, val != 0,
		20000, 2000000, false);
		return ret;
		}

		static void aqr107_chip_info(struct phy_device *phydev)