[SCSI] mac_esp: fix PIO mode, take 2

The mac_esp PIO algorithm no longer works in 2.6.31 and crashes my Centris
660av. So here's a better one.

Also, force async with esp_set_offset() rather than esp_slave_configure().

One of the SCSI drives I tested still doesn't like the PIO mode and fails
with "esp: esp0: Reconnect IRQ2 timeout" (the same drive works fine in
PDMA mode).

This failure happens when esp_reconnect_with_tag() tries to read in two
tag bytes but the chip only provides one (0x20). I don't know what causes
this. I decided not to waste any more time trying to fix it because the
best solution is to rip out the PIO mode altogether and use the DMA
engine.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 49 insertions, 46 deletions

diff --git a/drivers/scsi/mac_esp.c b/drivers/scsi/mac_esp.c
index c24e86f07804..dd808ae942a1 100644
--- a/drivers/scsi/mac_esp.c
+++ b/drivers/scsi/mac_esp.c
@@ -22,7 +22,6 @@
 
 #include <asm/irq.h>
 #include <asm/dma.h>
-
 #include <asm/macints.h>
 #include <asm/macintosh.h>
 
@@ -279,24 +278,27 @@ static void mac_esp_send_pdma_cmd(struct esp *esp, u32 addr, u32 esp_count,
  * Programmed IO routines follow.
  */
 
-static inline int mac_esp_wait_for_fifo(struct esp *esp)
+static inline unsigned int mac_esp_wait_for_fifo(struct esp *esp)
 {
         int i = 500000;
 
         do {
-                if (esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES)
-                        return 0;
+                unsigned int fbytes = esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES;
+
+                if (fbytes)
+                        return fbytes;
 
                 udelay(2);
         } while (--i);
 
         printk(KERN_ERR PFX "FIFO is empty (sreg %02x)\n",
                esp_read8(ESP_STATUS));
-        return 1;
+        return 0;
 }
 
 static inline int mac_esp_wait_for_intr(struct esp *esp)
 {
+        struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
         int i = 500000;
 
         do {
@@ -308,6 +310,7 @@ static inline int mac_esp_wait_for_intr(struct esp *esp)
         } while (--i);
 
         printk(KERN_ERR PFX "IRQ timeout (sreg %02x)\n", esp->sreg);
+        mep->error = 1;
         return 1;
 }
 
@@ -347,11 +350,10 @@ static inline int mac_esp_wait_for_intr(struct esp *esp)
 static void mac_esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
                                  u32 dma_count, int write, u8 cmd)
 {
-        unsigned long flags;
         struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
         u8 *fifo = esp->regs + ESP_FDATA * 16;
 
-        local_irq_save(flags);
+        disable_irq(esp->host->irq);
 
         cmd &= ~ESP_CMD_DMA;
         mep->error = 0;
@@ -359,11 +361,35 @@ static void mac_esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
         if (write) {
                 scsi_esp_cmd(esp, cmd);
 
-                if (!mac_esp_wait_for_intr(esp)) {
-                        if (mac_esp_wait_for_fifo(esp))
-                                esp_count = 0;
-                } else {
-                        esp_count = 0;
+                while (1) {
+                        unsigned int n;
+
+                        n = mac_esp_wait_for_fifo(esp);
+                        if (!n)
+                                break;
+
+                        if (n > esp_count)
+                                n = esp_count;
+                        esp_count -= n;
+
+                        MAC_ESP_PIO_LOOP("%2@,%0@+", n);
+
+                        if (!esp_count)
+                                break;
+
+                        if (mac_esp_wait_for_intr(esp))
+                                break;
+
+                        if (((esp->sreg & ESP_STAT_PMASK) != ESP_DIP) &&
+                            ((esp->sreg & ESP_STAT_PMASK) != ESP_MIP))
+                                break;
+
+                        esp->ireg = esp_read8(ESP_INTRPT);
+                        if ((esp->ireg & (ESP_INTR_DC | ESP_INTR_BSERV)) !=
+                            ESP_INTR_BSERV)
+                                break;
+
+                        scsi_esp_cmd(esp, ESP_CMD_TI);
                 }
         } else {
                 scsi_esp_cmd(esp, ESP_CMD_FLUSH);
@@ -374,47 +400,24 @@ static void mac_esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
                         MAC_ESP_PIO_LOOP("%0@+,%2@", esp_count);
 
                 scsi_esp_cmd(esp, cmd);
-        }
-
-        while (esp_count) {
-                unsigned int n;
-
-                if (mac_esp_wait_for_intr(esp)) {
-                        mep->error = 1;
-                        break;
-                }
-
-                if (esp->sreg & ESP_STAT_SPAM) {
-                        printk(KERN_ERR PFX "gross error\n");
-                        mep->error = 1;
-                        break;
-                }
 
-                n = esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES;
-
-                if (write) {
-                        if (n > esp_count)
-                                n = esp_count;
-                        esp_count -= n;
-
-                        MAC_ESP_PIO_LOOP("%2@,%0@+", n);
+                while (esp_count) {
+                        unsigned int n;
 
-                        if ((esp->sreg & ESP_STAT_PMASK) == ESP_STATP)
+                        if (mac_esp_wait_for_intr(esp))
                                 break;
 
-                        if (esp_count) {
-                                esp->ireg = esp_read8(ESP_INTRPT);
-                                if (esp->ireg & ESP_INTR_DC)
-                                        break;
+                        if (((esp->sreg & ESP_STAT_PMASK) != ESP_DOP) &&
+                            ((esp->sreg & ESP_STAT_PMASK) != ESP_MOP))
+                                break;
 
-                                scsi_esp_cmd(esp, ESP_CMD_TI);
-                        }
-                } else {
                         esp->ireg = esp_read8(ESP_INTRPT);
-                        if (esp->ireg & ESP_INTR_DC)
+                        if ((esp->ireg & (ESP_INTR_DC | ESP_INTR_BSERV)) !=
+                            ESP_INTR_BSERV)
                                 break;
 
-                        n = MAC_ESP_FIFO_SIZE - n;
+                        n = MAC_ESP_FIFO_SIZE -
+                            (esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES);
                         if (n > esp_count)
                                 n = esp_count;
 
@@ -429,7 +432,7 @@ static void mac_esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
                 }
         }
 
-        local_irq_restore(flags);
+        enable_irq(esp->host->irq);
 }
 
 static int mac_esp_irq_pending(struct esp *esp)