Subject: [PATCH][PPC32] Workaround for mpc10x speculative PCI read erratum

From: "Mark A. Greer" <[email-masked]>
Date: Thu, 27 Jan 2005 18:37:23 -0700

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.

Please apply.

Signed-off-by: Mark A. Greer <[email-masked]>
--
diff -Nru a/arch/ppc/syslib/mpc10x_common.c b/arch/ppc/syslib/mpc10x_common.c
--- a/arch/ppc/syslib/mpc10x_common.c	2005-01-27 18:31:21 -07:00
+++ b/arch/ppc/syslib/mpc10x_common.c	2005-01-27 18:31:21 -07:00
@@ -306,6 +306,23 @@
 	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 -Nru a/include/asm-ppc/mpc10x.h b/include/asm-ppc/mpc10x.h
--- a/include/asm-ppc/mpc10x.h	2005-01-27 18:31:21 -07:00
+++ b/include/asm-ppc/mpc10x.h	2005-01-27 18:31:21 -07:00
@@ -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