[PATCH] ahci: ignore PORT_IRQ_IF_ERR on JMB controllers

JMicron AHCI controllers set PORT_IRQ_IF_ERR on device errors.  The
IRQ status bit indicates interface error or protocol mismatch and ahci
driver interprets it into AC_ERR_ATA_BUS.  So, whenever an ATAPI
device raises check condition, ahci interprets it as ATA bus error and
thus resets it which, in turn, raises check condition thus creating a
reset loop and rendering the device unuseable.

This patch makes JMB controllers ignore PORT_IRQ_IF_ERR when
interpreting error condition.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Justin Tsai <justin@jmicron.com>

drivers/ata/ahci.c

@@ -78,6 +78,7 @@ enum {
 
 	board_ahci		= 0,
 	board_ahci_vt8251	= 1,
+	board_ahci_ign_iferr	= 2,
 
 	/* global controller registers */
 	HOST_CAP		= 0x00, /* host capabilities */
@@ -168,6 +169,7 @@ enum {
 	/* ap->flags bits */
 	AHCI_FLAG_RESET_NEEDS_CLO	= (1 << 24),
 	AHCI_FLAG_NO_NCQ		= (1 << 25),
+	AHCI_FLAG_IGN_IRQ_IF_ERR	= (1 << 26), /* ignore IRQ_IF_ERR */
 };
 
 struct ahci_cmd_hdr {
@@ -295,6 +297,17 @@ static const struct ata_port_info ahci_port_info[] = {
 		.udma_mask	= 0x7f, /* udma0-6 ; FIXME */
 		.port_ops	= &ahci_ops,
 	},
+	/* board_ahci_ign_iferr */
+	{
+		.sht		= &ahci_sht,
+		.flags		= ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY |
+				  ATA_FLAG_MMIO | ATA_FLAG_PIO_DMA |
+				  ATA_FLAG_SKIP_D2H_BSY |
+				  AHCI_FLAG_IGN_IRQ_IF_ERR,
+		.pio_mask	= 0x1f, /* pio0-4 */
+		.udma_mask	= 0x7f, /* udma0-6 ; FIXME */
+		.port_ops	= &ahci_ops,
+	},
 };
 
 static const struct pci_device_id ahci_pci_tbl[] = {
@@ -327,11 +340,11 @@ static const struct pci_device_id ahci_pci_tbl[] = {
 	{ PCI_VDEVICE(INTEL, 0x294e), board_ahci }, /* ICH9M */
 
 	/* JMicron */
-	{ PCI_VDEVICE(JMICRON, 0x2360), board_ahci }, /* JMicron JMB360 */
-	{ PCI_VDEVICE(JMICRON, 0x2361), board_ahci }, /* JMicron JMB361 */
-	{ PCI_VDEVICE(JMICRON, 0x2363), board_ahci }, /* JMicron JMB363 */
-	{ PCI_VDEVICE(JMICRON, 0x2365), board_ahci }, /* JMicron JMB365 */
-	{ PCI_VDEVICE(JMICRON, 0x2366), board_ahci }, /* JMicron JMB366 */
+	{ PCI_VDEVICE(JMICRON, 0x2360), board_ahci_ign_iferr }, /* JMB360 */
+	{ PCI_VDEVICE(JMICRON, 0x2361), board_ahci_ign_iferr }, /* JMB361 */
+	{ PCI_VDEVICE(JMICRON, 0x2363), board_ahci_ign_iferr }, /* JMB363 */
+	{ PCI_VDEVICE(JMICRON, 0x2365), board_ahci_ign_iferr }, /* JMB365 */
+	{ PCI_VDEVICE(JMICRON, 0x2366), board_ahci_ign_iferr }, /* JMB366 */
 
 	/* ATI */
 	{ PCI_VDEVICE(ATI, 0x4380), board_ahci }, /* ATI SB600 non-raid */
@@ -980,6 +993,10 @@ static void ahci_error_intr(struct ata_port *ap, u32 irq_stat)
 	/* analyze @irq_stat */
 	ata_ehi_push_desc(ehi, "irq_stat 0x%08x", irq_stat);
 
+	/* some controllers set IRQ_IF_ERR on device errors, ignore it */
+	if (ap->flags & AHCI_FLAG_IGN_IRQ_IF_ERR)
+		irq_stat &= ~PORT_IRQ_IF_ERR;
+
 	if (irq_stat & PORT_IRQ_TF_ERR)
 		err_mask |= AC_ERR_DEV;