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ata: pata_parport: fit3: implement IDE command set registers

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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>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
This commit is contained in:
Ondrej Zary 2023-10-05 22:55:59 +02:00 committed by Damien Le Moal
parent f343e578fe
commit 0c1e81d0b5
1 changed files with 2 additions and 12 deletions
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14
drivers/ata/pata_parport/fit3.c
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@ -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>
@ -37,8 +32,7 @@
static void fit3_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
{
if (cont == 1)
return;
regr += cont << 3;
switch (pi->mode) {
case 0:
@ -59,11 +53,7 @@ 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 << 3;
switch (pi->mode) {
case 0: