ata: pata_parport: fit3: implement IDE command set registers

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>

diff --git a/drivers/ata/pata_parport/fit3.c b/drivers/ata/pata_parport/fit3.c
index bad7aa9..d2b81cf 100644 (file)
--- 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>
@@ -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: