[PATCH] ppc32: Fix MPC52xx configuration space access

This patch takes care of an errata of the MPC5200 by avoiding 32 bits access
in type 1 configuration accesses.  All others accesses are still 32 bits wide.
 It also adds some mb() since the simple out_be(...) are not sufficient in
this case.
Signed-off-by: NSylvain Munaut <tnt@246tNt.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/ppc/syslib/mpc52xx_pci.c

@@ -24,6 +24,12 @@
 #include <asm/machdep.h>
 
 
+/* This macro is defined to activate the workaround for the bug
+   435 of the MPC5200 (L25R). With it activated, we don't do any
+   32 bits configuration access during type-1 cycles */
+#define MPC5200_BUG_435_WORKAROUND
+
+
 static int
 mpc52xx_pci_read_config(struct pci_bus *bus, unsigned int devfn,
 				int offset, int len, u32 *val)
@@ -40,17 +46,39 @@ mpc52xx_pci_read_config(struct pci_bus *bus, unsigned int devfn,
 		((bus->number - hose->bus_offset) << 16) |
 		(devfn << 8) |
 		(offset & 0xfc));
-
+	mb();
+
+#ifdef MPC5200_BUG_435_WORKAROUND
+	if (bus->number != hose->bus_offset) {
+		switch (len) {
+			case 1:
+				value = in_8(((u8 __iomem *)hose->cfg_data) + (offset & 3));
+				break;
+			case 2:
+				value = in_le16(((u16 __iomem *)hose->cfg_data) + ((offset>>1) & 1));
+				break;
+
+			default:
+				value = in_le16((u16 __iomem *)hose->cfg_data) |
+					(in_le16(((u16 __iomem *)hose->cfg_data) + 1) << 16);
+				break;
+		}
+	}
+	else
+#endif
+	{
 		value = in_le32(hose->cfg_data);
 
 		if (len != 4) {
 			value >>= ((offset & 0x3) << 3);
 			value &= 0xffffffff >> (32 - (len << 3));
 		}
+	}
 
 	*val = value;
 
 	out_be32(hose->cfg_addr, 0);
+	mb();
 
 	return PCIBIOS_SUCCESSFUL;
 }
@@ -71,7 +99,31 @@ mpc52xx_pci_write_config(struct pci_bus *bus, unsigned int devfn,
 		((bus->number - hose->bus_offset) << 16) |
 		(devfn << 8) |
 		(offset & 0xfc));
-
+	mb();
+
+#ifdef MPC5200_BUG_435_WORKAROUND
+	if (bus->number != hose->bus_offset) {
+		switch (len) {
+			case 1:
+				out_8(((u8 __iomem *)hose->cfg_data) +
+					(offset & 3), val);
+				break;
+			case 2:
+				out_le16(((u16 __iomem *)hose->cfg_data) +
+					((offset>>1) & 1), val);
+				break;
+
+			default:
+				out_le16((u16 __iomem *)hose->cfg_data,
+					(u16)val);
+				out_le16(((u16 __iomem *)hose->cfg_data) + 1,
+					(u16)(val>>16));
+				break;
+		}
+	}
+	else
+#endif
+	{
 		if (len != 4) {
 			value = in_le32(hose->cfg_data);
 
@@ -84,8 +136,11 @@ mpc52xx_pci_write_config(struct pci_bus *bus, unsigned int devfn,
 		}
 
 		out_le32(hose->cfg_data, val);
+	}
+	mb();
 
 	out_be32(hose->cfg_addr, 0);
+	mb();
 
 	return PCIBIOS_SUCCESSFUL;
 }