linux-kernel - Re: [PATCH 1/2] fsi/sbefifo: Clean up correct FIFO when receiving reset request from SBE

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Date:   Mon, 27 Jul 2020 15:51:05 +1000
From:   Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:     Joel Stanley <joel@....id.au>, linux-fsi@...ts.ozlabs.org
Cc:     Joachim Fenkes <FENKES@...ibm.com>, linux-kernel@...r.kernel.org,
        Jeremy Kerr <jk@...abs.org>,
        Alistar Popple <alistair@...ple.id.au>,
        Eddie James <eajames@...ux.ibm.com>
Subject: Re: [PATCH 1/2] fsi/sbefifo: Clean up correct FIFO when receiving
 reset request from SBE

On Fri, 2020-07-24 at 16:45 +0930, Joel Stanley wrote:
> From: Joachim Fenkes <FENKES@...ibm.com>
> 
> When the SBE requests a reset via the down FIFO, that is also the
> FIFO we should go and reset ;)

Is it ?

I no longer work for IBM and dont have access to any of the
documentation here but I had vague memories that we would get a reset
request in the down fifo in order to reset the up one since we control
the up one and the host controls the down one, no ?

Cheers,
Ben.

> Fixes: 9f4a8a2d7f9d ("fsi/sbefifo: Add driver for the SBE FIFO")
> Signed-off-by: Joachim Fenkes <FENKES@...ibm.com>
> Signed-off-by: Joel Stanley <joel@....id.au>
> ---
>  drivers/fsi/fsi-sbefifo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/fsi/fsi-sbefifo.c b/drivers/fsi/fsi-sbefifo.c
> index f54df9ebc8b3..655b45c1f6ba 100644
> --- a/drivers/fsi/fsi-sbefifo.c
> +++ b/drivers/fsi/fsi-sbefifo.c
> @@ -400,7 +400,7 @@ static int sbefifo_cleanup_hw(struct sbefifo
> *sbefifo)
>  	/* The FIFO already contains a reset request from the SBE ? */
>  	if (down_status & SBEFIFO_STS_RESET_REQ) {
>  		dev_info(dev, "Cleanup: FIFO reset request set,
> resetting\n");
> -		rc = sbefifo_regw(sbefifo, SBEFIFO_UP,
> SBEFIFO_PERFORM_RESET);
> +		rc = sbefifo_regw(sbefifo, SBEFIFO_DOWN,
> SBEFIFO_PERFORM_RESET);
>  		if (rc) {
>  			sbefifo->broken = true;
>  			dev_err(dev, "Cleanup: Reset reg write failed,
> rc=%d\n", rc);