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

Damien Le Moal
2023-10-03T00:56:43Z

On 10/1/23 04:15, 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>

For all patches of this series: please change the commit title to:

ata: pata_parport: xxx

> ---
> 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
> @@ -9,11 +9,6 @@
> *
> * The TD-2000 and certain older devices use a different protocol.
> * Try the fit2 protocol module with them.
> - *
> - * NB: The FIT adapters do not appear to support the control
> - * registers. So, we map ALT_STATUS to STATUS and NO-OP writes
> - * to the device control register - this means that IDE reset
> - * will not work on these devices.
> */
>
> #include <linux/module.h>
> @@ -35,10 +30,11 @@
> * cont = 1 - access the IDE command set
> */
>
> +static int cont_map[] = { 0x00, 0x08 };
> +
> static void fit3_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
> {
> - if (cont == 1)
> - return;
> + regr += cont_map[cont];
>
> 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];
>
> switch (pi->mode) {
> case 0:

--
Damien Le Moal
Western Digital Research