From: "Mark A. Greer" <mgreer@mvista.com>
824x and 107 bridges from Freescale/Tundra have an erratum where
speculative PCI reads may return stale data. One of the two documented
workarounds is to turn of speculative PCI reads. This patch does that.
Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/ppc/syslib/mpc10x_common.c | 17 +++++++++++++++++
25-akpm/include/asm-ppc/mpc10x.h | 1 +
2 files changed, 18 insertions(+)
diff -puN arch/ppc/syslib/mpc10x_common.c~ppc32-workaround-for-mpc10x-speculative-pci-read-erratum arch/ppc/syslib/mpc10x_common.c
--- 25/arch/ppc/syslib/mpc10x_common.c~ppc32-workaround-for-mpc10x-speculative-pci-read-erratum 2005-01-27 17:43:55.082204440 -0800
+++ 25-akpm/arch/ppc/syslib/mpc10x_common.c 2005-01-27 17:43:55.088203528 -0800
@@ -306,6 +306,23 @@ mpc10x_bridge_init(struct pci_controller
mpc10x_disable_store_gathering(hose);
#endif
+ /*
+ * 8240 erratum 26, 8241/8245 erratum 29, 107 erratum 23: speculative
+ * PCI reads may return stale data so turn off.
+ */
+ if ((host_bridge == MPC10X_BRIDGE_8240)
+ || (host_bridge == MPC10X_BRIDGE_8245)
+ || (host_bridge == MPC10X_BRIDGE_107)) {
+
+ early_read_config_dword(hose, 0, PCI_DEVFN(0,0),
+ MPC10X_CFG_PICR1_REG, &picr1);
+
+ picr1 &= ~MPC10X_CFG_PICR1_SPEC_PCI_RD;
+
+ early_write_config_dword(hose, 0, PCI_DEVFN(0,0),
+ MPC10X_CFG_PICR1_REG, picr1);
+ }
+
if (ppc_md.progress) ppc_md.progress("mpc10x:exit", 0x100);
return 0;
}
diff -puN include/asm-ppc/mpc10x.h~ppc32-workaround-for-mpc10x-speculative-pci-read-erratum include/asm-ppc/mpc10x.h
--- 25/include/asm-ppc/mpc10x.h~ppc32-workaround-for-mpc10x-speculative-pci-read-erratum 2005-01-27 17:43:55.084204136 -0800
+++ 25-akpm/include/asm-ppc/mpc10x.h 2005-01-27 17:43:55.089203376 -0800
@@ -105,6 +105,7 @@
#define MPC10X_CFG_PICR1_ADDR_MAP_MASK 0x00010000
#define MPC10X_CFG_PICR1_ADDR_MAP_A 0x00010000
#define MPC10X_CFG_PICR1_ADDR_MAP_B 0x00000000
+#define MPC10X_CFG_PICR1_SPEC_PCI_RD 0x00000004
#define MPC10X_CFG_PICR1_ST_GATH_EN 0x00000040
#define MPC10X_CFG_MAPB_OPTIONS_REG 0xe0
_