Re: [PATCH 2/2] hwmon (occ): Retry for checksum failure

[Eddie James]

On 4/25/22 04:10, David Laight wrote:
> From: Guenter Roeck
> > Sent: 24 April 2022 18:18
> >
> > On Mon, Mar 21, 2022 at 10:31:12AM -0500, Eddie James wrote:
> > > Due to the OCC communication design with a shared SRAM area,
> > > checkum errors are expected due to corrupted buffer from OCC
> > > communications with other system components. Therefore, retry
> > > the command twice in the event of a checksum failure.
> > >
> > > Signed-off-by: Eddie James <eajames@xxxxxxxxxxxxx>
> > I assume this will be applied together with patch 1 of the series.
> >
> > Acked-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> >
> > Guenter
> >
> > > ---
> > >   drivers/hwmon/occ/p9_sbe.c | 28 ++++++++++++++++++----------
> > >   1 file changed, 18 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/drivers/hwmon/occ/p9_sbe.c b/drivers/hwmon/occ/p9_sbe.c
> > > index 49b13cc01073..7f4c3f979c54 100644
> > > --- a/drivers/hwmon/occ/p9_sbe.c
> > > +++ b/drivers/hwmon/occ/p9_sbe.c
> > > @@ -84,17 +84,25 @@ static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd, size_t len)
> > >   	struct p9_sbe_occ *ctx = to_p9_sbe_occ(occ);
> > >   	size_t resp_len = sizeof(*resp);
> > >   	int rc;
> > > -
> > > -	rc = fsi_occ_submit(ctx->sbe, cmd, len, resp, &resp_len);
> > > -	if (rc < 0) {
> > > -		if (resp_len) {
> > > -			if (p9_sbe_occ_save_ffdc(ctx, resp, resp_len))
> > > -				sysfs_notify(&occ->bus_dev->kobj, NULL,
> > > -					     bin_attr_ffdc.attr.name);
> > > +	int tries = 0;
> > > +
> > > +	do {
> Why not use a for() loop?
>
> > > +		rc = fsi_occ_submit(ctx->sbe, cmd, len, resp, &resp_len);
> > > +		if (rc < 0) {
> > > +			if (resp_len) {
> > > +				if (p9_sbe_occ_save_ffdc(ctx, resp, resp_len))
> > > +					sysfs_notify(&occ->bus_dev->kobj, NULL,
> > > +						     bin_attr_ffdc.attr.name);
> > > +
> > > +				return rc;
> > > +			} else if (rc != -EBADE) {
> > > +				return rc;
> > > +			}
> No need for else after return.
>
> > > +			/* retry twice for checksum failures */
> > > +		} else {
> > > +			break;
> I'd break on the success path after testing (rc >= 0).
> Saves a level of indent.
>
> > >   		}
> > > -
> > > -		return rc;
> > > -	}
> > > +	} while (++tries < 3);
> > >
> > >   	switch (resp->return_status) {
> > >   	case OCC_RESP_CMD_IN_PRG:
> Probably end up with something like:
> 	for (tries = 0; tries < 3; tries++) {
> 		rc = ...;
> 		if (rc >= 0)
> 			break;
> 		if (resp_len) {
> 			...
> 			return rc;
> 		}
> 		if (rc != -EBADE)
> 			return rc;
> 	}
>
> 	David


Thanks David, Ack.


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