Re: [PATCH net] net: libwx: fix firmware mailbox abnormal return

[Jakub Kicinski <kuba@kernel.org>]

On Thu, 26 Dec 2024 11:18:10 +0800 Jiawen Wu wrote:
> Firmware writes back 'firmware ready' and 'unknown command' in the mailbox
> message if there is an unknown command sent by driver. It tends to happen
> with the use of custom firmware. So move the check for 'unknown command'
> out of the poll timeout for 'firmware ready'. And adjust the debug log so
> that mailbox messages are always printed when commands timeout.

The commit message doesn't really explain what the problem is, 
just what the code does. What is the problem you're solving 
and how does it impact the user?

> Fixes: 1efa9bfe58c5 ("net: libwx: Implement interaction with firmware")
> Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
> ---
>  drivers/net/ethernet/wangxun/libwx/wx_hw.c | 22 ++++++++++------------
>  1 file changed, 10 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/net/ethernet/wangxun/libwx/wx_hw.c b/drivers/net/ethernet/wangxun/libwx/wx_hw.c
> index 1bf9c38e4125..7059e0100c7c 100644
> --- a/drivers/net/ethernet/wangxun/libwx/wx_hw.c
> +++ b/drivers/net/ethernet/wangxun/libwx/wx_hw.c
> @@ -334,27 +334,25 @@ int wx_host_interface_command(struct wx *wx, u32 *buffer,
>  	status = read_poll_timeout(rd32, hicr, hicr & WX_MNG_MBOX_CTL_FWRDY, 1000,
>  				   timeout * 1000, false, wx, WX_MNG_MBOX_CTL);
>  
> +	buf[0] = rd32(wx, WX_MNG_MBOX);
> +	if ((buf[0] & 0xff0000) >> 16 == 0x80) {
> +		wx_dbg(wx, "It's unknown cmd.\n");
> +		status = -EINVAL;
> +		goto rel_out;
> +	}

Why check this before the status check? If the poll timed out doesn't
it mean the FW did not respond?

>  	/* Check command completion */
>  	if (status) {
>  		wx_dbg(wx, "Command has failed with no status valid.\n");
> -
> -		buf[0] = rd32(wx, WX_MNG_MBOX);
> -		if ((buffer[0] & 0xff) != (~buf[0] >> 24)) {
> -			status = -EINVAL;
> -			goto rel_out;
> -		}
> -		if ((buf[0] & 0xff0000) >> 16 == 0x80) {
> -			wx_dbg(wx, "It's unknown cmd.\n");
> -			status = -EINVAL;
> -			goto rel_out;
> -		}
> 
> +		wx_dbg(wx, "check: %x %x\n", buffer[0] & 0xff, ~buf[0] >> 24);
> +		if ((buffer[0] & 0xff) != (~buf[0] >> 24))
> +			goto rel_out;

Inverse question here, I guess. Why is it only an error for FW not 
to be ready if cmd doesn't match?
-- 
pw-bot: cr