powerpc/85xx: implement check for erratum A-004580 work-around

The work-around for erratum A-004580 ("Internal tracking loop can falsely
lock causing unrecoverable bit errors") is implemented via the PBI
(pre-boot initialization code, typically attached to the RCW binary).
This is because the work-around is easier to implement in PBI than in
U-Boot itself.

It is still useful, however, for the 'errata' command to tell us whether
the work-around has been applied.  For A-004580, we can do this by verifying
that the values in the specific registers that the work-around says to
update.

This change requires access to the SerDes lane sub-structure in
serdes_corenet_t, so we make it a named struct.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>

arch/powerpc/cpu/mpc85xx/cmd_errata.c

@@ -24,6 +24,7 @@
 #include <command.h>
 #include <linux/compiler.h>
 #include <asm/processor.h>
+#include "fsl_corenet_serdes.h"
 
 #ifdef CONFIG_SYS_FSL_ERRATUM_A004849
 /*
@@ -84,6 +85,49 @@ static void check_erratum_a4849(uint32_t svr)
 }
 #endif
 
+#ifdef CONFIG_SYS_FSL_ERRATUM_A004580
+/*
+ * This work-around is implemented in PBI, so just check to see if the
+ * work-around was actually applied.  To do this, we check for specific data
+ * at specific addresses in the SerDes register block.
+ *
+ * The work-around says that for each SerDes lane, write BnTTLCRy0 =
+ * 0x1B00_0001, Register 2 = 0x0088_0000, and Register 3 = 0x4000_0000.
+
+ */
+static void check_erratum_a4580(uint32_t svr)
+{
+	const serdes_corenet_t __iomem *srds_regs =
+		(void *)CONFIG_SYS_FSL_CORENET_SERDES_ADDR;
+	unsigned int lane;
+
+	for (lane = 0; lane < SRDS_MAX_LANES; lane++) {
+		if (serdes_lane_enabled(lane)) {
+			const struct serdes_lane __iomem *srds_lane =
+				&srds_regs->lane[serdes_get_lane_idx(lane)];
+
+			/*
+			 * Verify that the values we were supposed to write in
+			 * the PBI are actually there.  Also, the lower 15
+			 * bits of res4[3] should be the same as the upper 15
+			 * bits of res4[1].
+			 */
+			if ((in_be32(&srds_lane->ttlcr0) != 0x1b000001) ||
+			    (in_be32(&srds_lane->res4[1]) != 0x880000) ||
+			    (in_be32(&srds_lane->res4[3]) != 0x40000044)) {
+				printf("Work-around for Erratum A004580 is "
+				       "not enabled\n");
+				return;
+			}
+		}
+	}
+
+	/* Everything matches, so the erratum work-around was applied */
+
+	printf("Work-around for Erratum A004580 enabled\n");
+}
+#endif
+
 static int do_errata(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 #ifdef CONFIG_SYS_FSL_ERRATUM_NMG_CPU_A011
@@ -199,6 +243,10 @@ static int do_errata(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 #ifdef CONFIG_SYS_FSL_ERRATUM_A004849
 	/* This work-around is implemented in PBI, so just check for it */
 	check_erratum_a4849(svr);
+#endif
+#ifdef CONFIG_SYS_FSL_ERRATUM_A004580
+	/* This work-around is implemented in PBI, so just check for it */
+	check_erratum_a4580(svr);
 #endif
 	return 0;
 }

arch/powerpc/include/asm/config_mpc85xx.h

@@ -426,6 +426,7 @@
 #define CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY 0xff000000
 #define CONFIG_SYS_FSL_ERRATUM_SRIO_A004034
 #define CONFIG_SYS_FSL_ERRATUM_A004849
+#define CONFIG_SYS_FSL_ERRATUM_A004580
 
 #elif defined(CONFIG_PPC_P5020) /* also supports P5010 */
 #define CONFIG_SYS_PPC64		/* 64-bit core */

arch/powerpc/include/asm/immap_85xx.h

@@ -2619,7 +2619,7 @@ typedef struct serdes_corenet {
 #define SRDS_PCCR2_RST_XGMII1		0x00800000
 #define SRDS_PCCR2_RST_XGMII2		0x00400000
 	u32	res5[197];
-	struct {
+	struct serdes_lane {
 		u32	gcr0;	/* General Control Register 0 */
 #define SRDS_GCR0_RRST			0x00400000
 #define SRDS_GCR0_1STLANE		0x00010000