Re: [PATCH 4/4] pata_parport-fit3: implement IDE command set registers

Ondrej Zary
2023-10-03T17:13:37Z

On Monday 02 October 2023 22:06:52 Sergey Shtylyov wrote:
> On 9/30/23 10:15 PM, Ondrej Zary wrote:
>
> > fit3 protocol driver does not support accessing IDE control registers
> > (device control/altstatus). The DOS driver does not use these registers
> > either (as observed from DOSEMU trace). But the HW seems to be capable
> > of accessing these registers - I simply tried bit 3 and it works!
> >
> > The control register is required to properly reset ATAPI devices or
> > they will be detected only once (after a power cycle).
> >
> > Tested with EXP Computer CD-865 with MC-1285B EPP cable and
> > TransDisk 3000.
> >
> > Signed-off-by: Ondrej Zary <linux@zary.sk>
> > ---
> > drivers/ata/pata_parport/fit3.c | 16 ++++------------
> > 1 file changed, 4 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/ata/pata_parport/fit3.c b/drivers/ata/pata_parport/fit3.c
> > index bad7aa920cdc..86b39966755b 100644
> > --- a/drivers/ata/pata_parport/fit3.c
> > +++ b/drivers/ata/pata_parport/fit3.c
> [...]
> > @@ -35,10 +30,11 @@
> > * cont = 1 - access the IDE command set
> > */
> >
> > +static int cont_map[] = { 0x00, 0x08 };
>
> const?

There's no 'const' in other protocol drivers. Maybe it should be added to all of them.

> > +
> > static void fit3_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
> > {
> > - if (cont == 1)
> > - return;
> > + regr += cont_map[cont];
>
> Perhaps regr += cont << 3 instead?

I matched the style used by other protocol drivers.

> >
> > switch (pi->mode) {
> > case 0:
> > @@ -59,11 +55,7 @@ static int fit3_read_regr(struct pi_adapter *pi, int cont, int regr)
> > {
> > int a, b;
> >
> > - if (cont) {
> > - if (regr != 6)
> > - return 0xff;
> > - regr = 7;
> > - }
> > + regr += cont_map[cont];
>
> Likewise here?
>
> [...]
>
> MBR, Sergey
>

--
Ondrej Zary