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From: Ondrej Zary <linux@zary.sk>
To: Damien Le Moal <dlemoal@kernel.org>,
	Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Sergey Shtylyov <s.shtylyov@omp.ru>, Tim Waugh <tim@cyberelk.net>,
	linux-parport@lists.infradead.org, linux-ide@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 4/4] ata: pata_parport: fit3: implement IDE command set registers
Date: Wed,  4 Oct 2023 20:52:35 +0200	[thread overview]
Message-ID: <20231004185235.27417-5-linux@zary.sk> (raw)
In-Reply-To: <20231004185235.27417-1-linux@zary.sk>

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
@@ -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:
-- 
Ondrej Zary


  parent reply	other threads:[~2023-10-04 18:53 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-04 18:52 [PATCH v2 0/4] ata: pata_parport: fix EXP Computer CD-865 with MC-1285B EPP cable Ondrej Zary
2023-10-04 18:52 ` [PATCH 1/4] ata: pata_parport: fix pata_parport_devchk Ondrej Zary
2023-10-04 18:52 ` [PATCH 2/4] ata: pata_parport: implement set_devctl Ondrej Zary
2023-10-04 22:44   ` Damien Le Moal
2023-10-04 18:52 ` [PATCH 3/4] ata: pata_parport: add custom version of wait_after_reset Ondrej Zary
2023-10-04 18:52 ` Ondrej Zary [this message]
2023-10-04 22:43   ` [PATCH 4/4] ata: pata_parport: fit3: implement IDE command set registers Damien Le Moal
  -- strict thread matches above, loose matches on Subject: below --
2023-10-05 19:24 [PATCH v3 0/4] ata: pata_parport: fix EXP Computer CD-865 with MC-1285B EPP cable Ondrej Zary
2023-10-05 19:24 ` [PATCH 4/4] ata: pata_parport: fit3: implement IDE command set registers Ondrej Zary
2023-10-05 19:53   ` Sergey Shtylyov
2023-10-05 20:46     ` Ondrej Zary
2023-10-05 20:55 [PATCH v4 0/4] ata: pata_parport: fix EXP Computer CD-865 with MC-1285B EPP cable Ondrej Zary
2023-10-05 20:55 ` [PATCH 4/4] ata: pata_parport: fit3: implement IDE command set registers Ondrej Zary

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