[PATCH] alpha: cia-1 fix [5/10]

From Jay Estabrook:
CIA rev 1 can't use DAC and windows 1,2 for SG.

arch/alpha/kernel/core_cia.c

@@ -370,7 +370,7 @@ cia_pci_tbi_try2(struct pci_controller *hose,
 }
 
 static inline void
-cia_prepare_tbia_workaround(void)
+cia_prepare_tbia_workaround(int cia_rev, int is_pyxis)
 {
 	unsigned long *ppte, pte;
 	long i;
@@ -382,10 +382,20 @@ cia_prepare_tbia_workaround(void)
 	for (i = 0; i < CIA_BROKEN_TBIA_SIZE / sizeof(unsigned long); ++i)
 		ppte[i] = pte;
 
+	if (is_pyxis || cia_rev != 1) {
+		/* We can use W1 for SG on PYXIS/CIA rev 2. */
 		*(vip)CIA_IOC_PCI_W1_BASE = CIA_BROKEN_TBIA_BASE | 3;
 		*(vip)CIA_IOC_PCI_W1_MASK = (CIA_BROKEN_TBIA_SIZE*1024 - 1)
 					    & 0xfff00000;
 		*(vip)CIA_IOC_PCI_T1_BASE = virt_to_phys(ppte) >> 2;
+	} else {
+		/* CIA rev 1 can't use W1 or W2 for SG, apparently,
+		   so use W3, which we made sure is not used for DAC. */
+		*(vip)CIA_IOC_PCI_W3_BASE = CIA_BROKEN_TBIA_BASE | 3;
+		*(vip)CIA_IOC_PCI_W3_MASK = (CIA_BROKEN_TBIA_SIZE*1024 - 1)
+					    & 0xfff00000;
+		*(vip)CIA_IOC_PCI_T3_BASE = virt_to_phys(ppte) >> 2;
+	}
 }
 
 static void __init
@@ -684,10 +694,10 @@ do_init_arch(int is_pyxis)
 	/*
 	 * Set up the PCI to main memory translation windows.
 	 *
-	 * Window 0 is scatter-gather 8MB at 8MB (for isa)
-	 * Window 1 is scatter-gather 1MB at 768MB (for tbia)
+	 * Window 0 is S/G 8MB at 8MB (for isa)
+	 * Window 1 is S/G 1MB at 768MB (for tbia) (unused for CIA rev 1)
 	 * Window 2 is direct access 2GB at 2GB
-	 * Window 3 is DAC access 4GB at 8GB
+	 * Window 3 is DAC access 4GB at 8GB (or S/G for tbia if CIA rev 1)
 	 *
 	 * ??? NetBSD hints that page tables must be aligned to 32K,
 	 * possibly due to a hardware bug.  This is over-aligned
@@ -697,6 +707,7 @@ do_init_arch(int is_pyxis)
 
 	hose->sg_pci = NULL;
 	hose->sg_isa = iommu_arena_new(hose, 0x00800000, 0x00800000, 32768);
+
 	__direct_map_base = 0x80000000;
 	__direct_map_size = 0x80000000;
 
@@ -715,8 +726,14 @@ do_init_arch(int is_pyxis)
 	   are compared against W_DAC.  We can, however, directly map 4GB,
 	   which is better than before.  However, due to assumptions made
 	   elsewhere, we should not claim that we support DAC unless that
-	   4GB covers all of physical memory.  */
-	if (is_pyxis || max_low_pfn > (0x100000000 >> PAGE_SHIFT)) {
+	   4GB covers all of physical memory.
+
+	   Also, don't do DAC on CIA rev 1, it has other problems and is
+	   unlikely to have more than 2GB of memory anyway, so direct is
+	   fine.
+	*/
+	if (cia_rev == 1 || is_pyxis ||
+	    max_low_pfn > (0x100000000UL >> PAGE_SHIFT)) {
 		*(vip)CIA_IOC_PCI_W3_BASE = 0;
 	} else {
 		*(vip)CIA_IOC_PCI_W3_BASE = 0x00000000 | 1 | 8;
@@ -728,7 +745,7 @@ do_init_arch(int is_pyxis)
 	}
 
 	/* Prepare workaround for apparently broken tbia. */
-	cia_prepare_tbia_workaround();
+	cia_prepare_tbia_workaround(cia_rev, is_pyxis);
 }
 
 void __init