[SCSI] m68k: mac_esp asm fix

Fix asm constraints and arguments so as not to transfer an odd byte when
there may be more words to transfer. The bug would probably also cause
exceptions sometimes by transferring one too many bytes.
Signed-off-by: NFinn Thain <fthain@telegraphics.com.au>
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/mac_esp.c

@@ -170,7 +170,7 @@ static inline int mac_esp_wait_for_dreq(struct esp *esp)
 
 #define MAC_ESP_PDMA_LOOP(operands) \
 	asm volatile ( \
-	     "       tstw %2                   \n" \
+	     "       tstw %1                   \n" \
 	     "       jbeq 20f                  \n" \
 	     "1:     movew " operands "        \n" \
 	     "2:     movew " operands "        \n" \
@@ -188,14 +188,14 @@ static inline int mac_esp_wait_for_dreq(struct esp *esp)
 	     "14:    movew " operands "        \n" \
 	     "15:    movew " operands "        \n" \
 	     "16:    movew " operands "        \n" \
-	     "       subqw #1,%2               \n" \
+	     "       subqw #1,%1               \n" \
 	     "       jbne 1b                   \n" \
-	     "20:    tstw %3                   \n" \
+	     "20:    tstw %2                   \n" \
 	     "       jbeq 30f                  \n" \
 	     "21:    movew " operands "        \n" \
-	     "       subqw #1,%3               \n" \
+	     "       subqw #1,%2               \n" \
 	     "       jbne 21b                  \n" \
-	     "30:    tstw %4                   \n" \
+	     "30:    tstw %3                   \n" \
 	     "       jbeq 40f                  \n" \
 	     "31:    moveb " operands "        \n" \
 	     "32:    nop                       \n" \
@@ -223,8 +223,8 @@ static inline int mac_esp_wait_for_dreq(struct esp *esp)
 	     "       .long  31b,40b            \n" \
 	     "       .long  32b,40b            \n" \
 	     "       .previous                 \n" \
-	     : "+a" (addr) \
-	     : "a" (mep->pdma_io), "r" (count32), "r" (count2), "g" (esp_count))
+	     : "+a" (addr), "+r" (count32), "+r" (count2) \
+	     : "g" (count1), "a" (mep->pdma_io))
 
 static void mac_esp_send_pdma_cmd(struct esp *esp, u32 addr, u32 esp_count,
 				  u32 dma_count, int write, u8 cmd)
@@ -247,19 +247,20 @@ static void mac_esp_send_pdma_cmd(struct esp *esp, u32 addr, u32 esp_count,
 	do {
 		unsigned int count32 = esp_count >> 5;
 		unsigned int count2 = (esp_count & 0x1F) >> 1;
+		unsigned int count1 = esp_count & 1;
 		unsigned int start_addr = addr;
 
 		if (mac_esp_wait_for_dreq(esp))
 			break;
 
 		if (write) {
-			MAC_ESP_PDMA_LOOP("%1@,%0@+");
+			MAC_ESP_PDMA_LOOP("%4@,%0@+");
 
 			esp_count -= addr - start_addr;
 		} else {
 			unsigned int n;
 
-			MAC_ESP_PDMA_LOOP("%0@+,%1@");
+			MAC_ESP_PDMA_LOOP("%0@+,%4@");
 
 			if (mac_esp_wait_for_empty_fifo(esp))
 				break;