IB/ipath: Add flag and handling for chips with swapped register bug

The 6110 had a bug that caused some registers to be swapped; it was
fixed for the 7220 (and didn't affect the 6120 because it had fewer
registers).  This adds a flag and related code to handle that, and
includes some minor cleanups in the same area.

Signed-off-by:  Ralph Campbell <ralph.campbell@qlogic.com>

drivers/infiniband/hw/ipath/ipath_driver.c

@@ -1340,14 +1340,9 @@ static void ipath_update_pio_bufs(struct ipath_devdata *dd)
 		/*
 		 * Chip Errata: bug 6641; even and odd qwords>3 are swapped
 		 */
-		if (i > 3) {
-			if (i & 1)
-				piov = le64_to_cpu(
-					dd->ipath_pioavailregs_dma[i - 1]);
-			else
-				piov = le64_to_cpu(
-					dd->ipath_pioavailregs_dma[i + 1]);
-		} else
+		if (i > 3 && (dd->ipath_flags & IPATH_SWAP_PIOBUFS))
+			piov = le64_to_cpu(dd->ipath_pioavailregs_dma[i ^ 1]);
+		else
 			piov = le64_to_cpu(dd->ipath_pioavailregs_dma[i]);
 		pchg = _IPATH_ALL_CHECKBITS &
 			~(dd->ipath_pioavailshadow[i] ^ piov);

drivers/infiniband/hw/ipath/ipath_iba6110.c

@@ -1043,6 +1043,8 @@ static int ipath_setup_ht_config(struct ipath_devdata *dd,
 	} while ((pos = pci_find_next_capability(pdev, pos,
 						 PCI_CAP_ID_HT)));
 
+	dd->ipath_flags |= IPATH_SWAP_PIOBUFS;
+
 bail:
 	return ret;
 }

drivers/infiniband/hw/ipath/ipath_init_chip.c

@@ -528,12 +528,8 @@ static void enable_chip(struct ipath_devdata *dd,
 		/*
 		 * Chip Errata bug 6641; even and odd qwords>3 are swapped.
 		 */
-		if (i > 3) {
-			if (i & 1)
-				val = dd->ipath_pioavailregs_dma[i - 1];
-			else
-				val = dd->ipath_pioavailregs_dma[i + 1];
-		}
+		if (i > 3 && (dd->ipath_flags & IPATH_SWAP_PIOBUFS))
+			val = dd->ipath_pioavailregs_dma[i ^ 1];
 		else
 			val = dd->ipath_pioavailregs_dma[i];
 		dd->ipath_pioavailshadow[i] = le64_to_cpu(val);

drivers/infiniband/hw/ipath/ipath_intr.c

@@ -831,8 +831,8 @@ void ipath_clear_freeze(struct ipath_devdata *dd)
 	 */
 	for (i = 0; i < dd->ipath_pioavregs; i++) {
 		/* deal with 6110 chip bug */
-		im = i > 3 ? ((i&1) ? i-1 : i+1) : i;
-		val = ipath_read_kreg64(dd, (0x1000/sizeof(u64))+im);
+		im = i > 3 ? i ^ 1 : i;
+		val = ipath_read_kreg64(dd, (0x1000 / sizeof(u64)) + im);
 		dd->ipath_pioavailregs_dma[i] = dd->ipath_pioavailshadow[i]
 			= le64_to_cpu(val);
 	}

drivers/infiniband/hw/ipath/ipath_kernel.h

@@ -756,6 +756,7 @@ int ipath_set_rx_pol_inv(struct ipath_devdata *dd, u8 new_pol_inv);
 #define IPATH_DISABLED      0x80000 /* administratively disabled */
 		/* Use GPIO interrupts for new counters */
 #define IPATH_GPIO_ERRINTRS 0x100000
+#define IPATH_SWAP_PIOBUFS  0x200000
 
 /* Bits in GPIO for the added interrupts */
 #define IPATH_GPIO_PORT0_BIT 2