Re: [PATCH 3/4] pata_parport: add custom version of wait_after_reset

Ondrej Zary
2023-10-03T17:20:39Z

On Monday 02 October 2023 22:48:59 Sergey Shtylyov wrote:
> On 9/30/23 10:15 PM, Ondrej Zary wrote:
>
> > Some parallel adapters (e.g. EXP Computer MC-1285B EPP Cable) return
> > bogus values when there's no master device present. This can cause
> > reset to fail, preventing the lone slave device (such as EXP Computer
> > CD-865) from working.
> >
> > Add custom version of wait_after_reset that ignores master failure when
> > a slave device is present. The custom version is also needed because
> > the generic ata_sff_wait_after_reset uses direct port I/O for slave
> > device detection.
> >
> > Signed-off-by: Ondrej Zary <linux@zary.sk>
> > ---
> > drivers/ata/pata_parport/pata_parport.c | 65 ++++++++++++++++++++++++-
> > 1 file changed, 64 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/ata/pata_parport/pata_parport.c b/drivers/ata/pata_parport/pata_parport.c
> > index cf87bbb52f1f..b3db953e615a 100644
> > --- a/drivers/ata/pata_parport/pata_parport.c
> > +++ b/drivers/ata/pata_parport/pata_parport.c
> > @@ -80,6 +80,69 @@ static bool pata_parport_devchk(struct ata_port *ap, unsigned int device)
> > return (nsect == 0x55) && (lbal == 0xaa);
> > }
> >
> > +static int pata_parport_wait_after_reset(struct ata_link *link,
> > + unsigned int devmask,
> > + unsigned long deadline)
> > +{
> > + struct ata_port *ap = link->ap;
> > + struct pi_adapter *pi = ap->host->private_data;
> > + unsigned int dev0 = devmask & (1 << 0);
> > + unsigned int dev1 = devmask & (1 << 1);
> > + int rc, ret = 0;
> > +
> > + ata_msleep(ap, ATA_WAIT_AFTER_RESET);
> > +
> > + /* always check readiness of the master device */
> > + rc = ata_sff_wait_ready(link, deadline);
> > + /* some adapters return bogus values if master device is not present,
>
> The multiline comments should start with /* on its own line.
> Have you run scripts/checkpatch.pl on the patches?

Checkpatch doesn't complain.

> > + * so don't abort now if a slave device is present
> > + */
> > + if (rc) {
> > + if (!dev1)
> > + return rc;
> > + ret = -ENODEV;
> > + }
> > +
> > + /* if device 1 was found in ata_devchk, wait for register
>
> Likewise here...
>
> > + * access briefly, then wait for BSY to clear.
> > + */
> > + if (dev1) {
> > + int i;
> > +
> > + pata_parport_dev_select(ap, 1);
> > +
> > + /* Wait for register access. Some ATAPI devices fail
>
> And here...
>
> [...]
>
> MBR, Sergey
>

--
Ondrej Zary