[PATCH v4 0/2] Some esp_scsi updates

[PATCH v4 0/2] Some esp_scsi updates

[Kars de Jong]

When trying kernel 5.4.0-rc5 on my Amiga, I experienced data transfer failures
when reading from my FAST-10 SCSI disk. I have a Blizzard 12x0 IV SCSI
controller which uses a Symbios Logic SYM53CF94-2 "FSC" chip.

This used to work with the old generic NCR53C9x driver, so I investigated the
issue.

It turned out to be caused by lacking detection of FSC silicon in the new
driver.

The second patch in this series adds support for the FSC.

When adding support for the chip, I found out the hard way that the esp_rev
enum is ordered (I just added it to the end of the enum).

Then I also discovered that the definition for the PCSCSI chip was in the
wrong place of the enum. It will probably have issues with FAST-10 SCSI
targets, because its CONFIG3 settings are wrong.

The first patch fixes this, and adds comments to the enum to hopefully prevent
this from happening again.

When discussing this on the Linux/m68k mailing list, it was suggested to
perhaps replace the dependency on ordering of the esp_rev enum by feature flags.
I did not implement this for now.

Changes since v3:
- Reduce scope of family_code variable
- Remove some redundant comments
- Explicitly show the NCR/Symbios Logic part code instead of FSC, which is
  only used in the data manual

Changes since v2:
- Fixed merge conflict in second patch

Changes since v1:
- Removed confusing comments from esp_rev enum
- Remove unneeded definitions for UID register
- Remove unneeded local uid variable

Kars de Jong (2):
  esp_scsi: Correct ordering of PCSCSI definition in esp_rev enum
  esp_scsi: Add support for FSC chip

 drivers/scsi/esp_scsi.c | 20 +++++++++++---------
 drivers/scsi/esp_scsi.h | 41 +++++++++++++++++++++++++----------------
 2 files changed, 36 insertions(+), 25 deletions(-)

-- 
2.17.1

[PATCH v4 1/2] esp_scsi: Correct ordering of PCSCSI definition in esp_rev enum

[Kars de Jong]

The order of the definitions in the esp_rev enum is important. The values
are used in comparisons for chip features.

Add a comment to the enum explaining this.

Also, the actual values for the enum fields are irrelevant, so remove the
explicit values (suggested by Geert Uytterhoeven). This makes adding a new
field in the middle of the enum easier.

Finally, move the PCSCSI definition to the right place in the enum. In its
previous location, at the end of the enum, the wrong values are written to
the CONFIG3 register when used with FAST-SCSI targets.

Signed-off-by: Kars de Jong <jongk@linux-m68k.org>
---
 drivers/scsi/esp_scsi.c |  2 +-
 drivers/scsi/esp_scsi.h | 17 +++++++++--------
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
index bb88995a12c7..4fc3eee3138b 100644
--- a/drivers/scsi/esp_scsi.c
+++ b/drivers/scsi/esp_scsi.c
@@ -2373,10 +2373,10 @@ static const char *esp_chip_names[] = {
 	"ESP100A",
 	"ESP236",
 	"FAS236",
+	"AM53C974",
 	"FAS100A",
 	"FAST",
 	"FASHME",
-	"AM53C974",
 };
 
 static struct scsi_transport_template *esp_transport_template;
diff --git a/drivers/scsi/esp_scsi.h b/drivers/scsi/esp_scsi.h
index 91b32f2a1a1b..f764d64e1f25 100644
--- a/drivers/scsi/esp_scsi.h
+++ b/drivers/scsi/esp_scsi.h
@@ -257,15 +257,16 @@ struct esp_cmd_priv {
 };
 #define ESP_CMD_PRIV(CMD)	((struct esp_cmd_priv *)(&(CMD)->SCp))
 
+/* NOTE: this enum is ordered based on chip features! */
 enum esp_rev {
-	ESP100     = 0x00,  /* NCR53C90 - very broken */
-	ESP100A    = 0x01,  /* NCR53C90A */
-	ESP236     = 0x02,
-	FAS236     = 0x03,
-	FAS100A    = 0x04,
-	FAST       = 0x05,
-	FASHME     = 0x06,
-	PCSCSI     = 0x07,  /* AM53c974 */
+	ESP100,  /* NCR53C90 - very broken */
+	ESP100A, /* NCR53C90A */
+	ESP236,
+	FAS236,
+	PCSCSI,  /* AM53c974 */
+	FAS100A,
+	FAST,
+	FASHME,
 };
 
 struct esp_cmd_entry {
-- 
2.17.1

[PATCH v4 2/2] esp_scsi: Add support for FSC chip

[Kars de Jong]

The FSC (NCR53CF9x-2 / SYM53CF9x-2) has a different family code than QLogic
or Emulex parts. This caused it to be detected as a FAS100A.

Unforunately, this meant the configuration of the CONFIG3 register was
incorrect. This causes data transfer issues with FAST-SCSI targets.

The FSC also has the CONFIG4 register. It can be used to enable a feature
called Active Negation which should always be enabled according to the data
manual.

Signed-off-by: Kars de Jong <jongk@linux-m68k.org>
---
 drivers/scsi/esp_scsi.c | 18 ++++++++++--------
 drivers/scsi/esp_scsi.h | 24 ++++++++++++++++--------
 2 files changed, 26 insertions(+), 16 deletions(-)

diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
index 4fc3eee3138b..1cfb1689bed5 100644
--- a/drivers/scsi/esp_scsi.c
+++ b/drivers/scsi/esp_scsi.c
@@ -243,8 +243,6 @@ static void esp_set_all_config3(struct esp *esp, u8 val)
 /* Reset the ESP chip, _not_ the SCSI bus. */
 static void esp_reset_esp(struct esp *esp)
 {
-	u8 family_code, version;
-
 	/* Now reset the ESP chip */
 	scsi_esp_cmd(esp, ESP_CMD_RC);
 	scsi_esp_cmd(esp, ESP_CMD_NULL | ESP_CMD_DMA);
@@ -257,13 +255,16 @@ static void esp_reset_esp(struct esp *esp)
 	 */
 	esp->max_period = ((35 * esp->ccycle) / 1000);
 	if (esp->rev == FAST) {
-		version = esp_read8(ESP_UID);
-		family_code = (version & 0xf8) >> 3;
-		if (family_code == 0x02)
+		u8 family_code = ESP_FAMILY(esp_read8(ESP_UID));
+		if (family_code == ESP_UID_F236)
 			esp->rev = FAS236;
-		else if (family_code == 0x0a)
+		else if (family_code == ESP_UID_HME)
 			esp->rev = FASHME; /* Version is usually '5'. */
-		else
+		else if (family_code == ESP_UID_FSC) {
+			esp->rev = FSC;
+			/* Enable Active Negation */
+			esp_write8(ESP_CONFIG4_RADE, ESP_CFG4);
+		} else
 			esp->rev = FAS100A;
 		esp->min_period = ((4 * esp->ccycle) / 1000);
 	} else {
@@ -308,7 +309,7 @@ static void esp_reset_esp(struct esp *esp)
 
 	case FAS236:
 	case PCSCSI:
-		/* Fast 236, AM53c974 or HME */
+	case FSC:
 		esp_write8(esp->config2, ESP_CFG2);
 		if (esp->rev == FASHME) {
 			u8 cfg3 = esp->target[0].esp_config3;
@@ -2374,6 +2375,7 @@ static const char *esp_chip_names[] = {
 	"ESP236",
 	"FAS236",
 	"AM53C974",
+	"53CF9x-2",
 	"FAS100A",
 	"FAST",
 	"FASHME",
diff --git a/drivers/scsi/esp_scsi.h b/drivers/scsi/esp_scsi.h
index f764d64e1f25..446a3d18c022 100644
--- a/drivers/scsi/esp_scsi.h
+++ b/drivers/scsi/esp_scsi.h
@@ -78,12 +78,14 @@
 #define ESP_CONFIG3_IMS       0x80     /* ID msg chk'ng        (esp/fas236)  */
 #define ESP_CONFIG3_OBPUSH    0x80     /* Push odd-byte to dma (hme)         */
 
-/* ESP config register 4 read-write, found only on am53c974 chips */
-#define ESP_CONFIG4_RADE      0x04     /* Active negation */
-#define ESP_CONFIG4_RAE       0x08     /* Active negation on REQ and ACK */
-#define ESP_CONFIG4_PWD       0x20     /* Reduced power feature */
-#define ESP_CONFIG4_GE0       0x40     /* Glitch eater bit 0 */
-#define ESP_CONFIG4_GE1       0x80     /* Glitch eater bit 1 */
+/* ESP config register 4 read-write */
+#define ESP_CONFIG4_BBTE      0x01     /* Back-to-back transfers     (fsc)   */
+#define ESP_CONGIG4_TEST      0x02     /* Transfer counter test mode (fsc)   */
+#define ESP_CONFIG4_RADE      0x04     /* Active negation   (am53c974/fsc)   */
+#define ESP_CONFIG4_RAE       0x08     /* Act. negation REQ/ACK (am53c974)   */
+#define ESP_CONFIG4_PWD       0x20     /* Reduced power feature (am53c974)   */
+#define ESP_CONFIG4_GE0       0x40     /* Glitch eater bit 0    (am53c974)   */
+#define ESP_CONFIG4_GE1       0x80     /* Glitch eater bit 1    (am53c974)   */
 
 #define ESP_CONFIG_GE_12NS    (0)
 #define ESP_CONFIG_GE_25NS    (ESP_CONFIG_GE1)
@@ -209,10 +211,15 @@
 #define ESP_TEST_TS           0x04     /* Tristate test mode */
 
 /* ESP unique ID register read-only, found on fas236+fas100a only */
+#define ESP_UID_FAM           0xf8     /* ESP family bitmask */
+
+#define ESP_FAMILY(uid) (((uid) & ESP_UID_FAM) >> 3)
+
+/* Values for the ESP family bits */
 #define ESP_UID_F100A         0x00     /* ESP FAS100A  */
 #define ESP_UID_F236          0x02     /* ESP FAS236   */
-#define ESP_UID_REV           0x07     /* ESP revision */
-#define ESP_UID_FAM           0xf8     /* ESP family   */
+#define ESP_UID_HME           0x0a     /* FAS HME      */
+#define ESP_UID_FSC           0x14     /* NCR/Symbios Logic 53CF9x-2 */
 
 /* ESP fifo flags register read-only */
 /* Note that the following implies a 16 byte FIFO on the ESP. */
@@ -264,6 +271,7 @@ enum esp_rev {
 	ESP236,
 	FAS236,
 	PCSCSI,  /* AM53c974 */
+	FSC,     /* NCR/Symbios Logic 53CF9x-2 */
 	FAS100A,
 	FAST,
 	FASHME,
-- 
2.17.1