linux-kernel - Re: [RESEND PATCH net-next v3 2/4] net: phy: aquantia: wait for FW reset before checking the vendor ID

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Message-ID: <8ac00a45-ac61-41b4-9f74-d18157b8b6bf@nvidia.com>
Date: Tue, 30 Jul 2024 10:59:59 +0100
From: Jon Hunter <jonathanh@...dia.com>
To: Bartosz Golaszewski <brgl@...ev.pl>, Andrew Lunn <andrew@...n.ch>,
 Heiner Kallweit <hkallweit1@...il.com>, Russell King
 <linux@...linux.org.uk>, "David S . Miller" <davem@...emloft.net>,
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
 Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
 "linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
 Brad Griffis <bgriffis@...dia.com>
Subject: Re: [RESEND PATCH net-next v3 2/4] net: phy: aquantia: wait for FW
 reset before checking the vendor ID

Hi Bartosz,

On 08/07/2024 08:50, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> 
> Checking the firmware register before it complete the boot process makes
> no sense, it will report 0 even if FW is available from internal memory.
> Always wait for FW to boot before continuing or we'll unnecessarily try
> to load it from nvmem/filesystem and fail.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> ---
>   drivers/net/phy/aquantia/aquantia_firmware.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/net/phy/aquantia/aquantia_firmware.c b/drivers/net/phy/aquantia/aquantia_firmware.c
> index 0c9640ef153b..524627a36c6f 100644
> --- a/drivers/net/phy/aquantia/aquantia_firmware.c
> +++ b/drivers/net/phy/aquantia/aquantia_firmware.c
> @@ -353,6 +353,10 @@ int aqr_firmware_load(struct phy_device *phydev)
>   {
>   	int ret;
>   
> +	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.

Although this fixed another issue we were seeing with this driver, we 
have been reviewing this change and have a question about it.

According to the description for the function aqr_wait_reset_complete() 
this function is intended to give the device time to load firmware and 
check there is a valid firmware ID.

If a valid firmware ID (non-zero) is detected, then 
aqr_wait_reset_complete() will return 0 (because 
phy_read_mmd_poll_timeout() returns 0 on success and -ETIMEDOUT upon a 
timeout).

If it times out, then it would appear that with the above code we don't 
attempt to load the firmware by any other means?

Hence, I was wondering if we want this ...

diff --git a/drivers/net/phy/aquantia/aquantia_firmware.c 
b/drivers/net/phy/aquantia/aquantia_firmware.c
index 524627a36c6f..a167f42ae36b 100644
--- a/drivers/net/phy/aquantia/aquantia_firmware.c
+++ b/drivers/net/phy/aquantia/aquantia_firmware.c
@@ -353,16 +353,12 @@ int aqr_firmware_load(struct phy_device *phydev)
  {
         int ret;

-       ret = aqr_wait_reset_complete(phydev);
-       if (ret)
-               return ret;
-
-       /* Check if the firmware is not already loaded by pooling
+       /* Check if the firmware is not already loaded by polling
          * the current version returned by the PHY. If 0 is returned,
-        * no firmware is loaded.
+        * firmware is loaded.
          */
-       ret = phy_read_mmd(phydev, MDIO_MMD_VEND1, VEND1_GLOBAL_FW_ID);
-       if (ret > 0)
+       ret = aqr_wait_reset_complete(phydev);
+       if (!ret)
                 goto exit;

         ret = aqr_firmware_load_nvmem(phydev);

Our Aquantia PHY has a SPI-NOR and so we don't to test the other 
firmware loading cases.

Jon

-- 
nvpublic