[U-Boot] [PATCH 11/11] powerpc/mpc85xx: Workaround for A-005812

[York Sun]

Erratum A-005812 Incorrect reservation clearing in Write Shadow mode can
result in invalid atomic operations. For u-boot, this erratum only impacts
SoCs running in write shadow mode.

Signed-off-by: York Sun <yorksun at freescale.com>
---
 arch/powerpc/cpu/mpc85xx/cmd_errata.c     |    3 +++
 arch/powerpc/cpu/mpc85xx/cpu_init.c       |    8 ++++++++
 arch/powerpc/cpu/mpc85xx/release.S        |   15 +++++++++++++++
 arch/powerpc/include/asm/config_mpc85xx.h |    3 +++
 4 files changed, 29 insertions(+)

diff --git a/arch/powerpc/cpu/mpc85xx/cmd_errata.c b/arch/powerpc/cpu/mpc85xx/cmd_errata.c
index 422782c..7db06ac 100644
--- a/arch/powerpc/cpu/mpc85xx/cmd_errata.c
+++ b/arch/powerpc/cpu/mpc85xx/cmd_errata.c
@@ -258,6 +258,9 @@ static int do_errata(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 #ifdef CONFIG_SYS_FSL_ERRATUM_USB14
 	puts("Work-around for Erratum USB14 enabled\n");
 #endif
+#ifdef CONFIG_SYS_FSL_ERRATUM_A005812
+	puts("Work-around for Erratum A-005812 enabled\n");
+#endif
 	return 0;
 }
 
diff --git a/arch/powerpc/cpu/mpc85xx/cpu_init.c b/arch/powerpc/cpu/mpc85xx/cpu_init.c
index fd19d99..ca799ac 100644
--- a/arch/powerpc/cpu/mpc85xx/cpu_init.c
+++ b/arch/powerpc/cpu/mpc85xx/cpu_init.c
@@ -412,6 +412,14 @@ int cpu_init_r(void)
 		sync();
 	}
 #endif
+#ifdef CONFIG_SYS_FSL_ERRATUM_A005812
+	/*
+	 * A-005812 workaround sets bit 32 of SPR 976 for SoCs running
+	 * in write shadow mode. Checking DCWS before setting SPR 976.
+	 */
+	if (mfspr(L1CSR2) & L1CSR2_DCWS)
+		mtspr(SPRN_HDBCR0, (mfspr(SPRN_HDBCR0) | 0x80000000));
+#endif
 
 #if defined(CONFIG_PPC_SPINTABLE_COMPATIBLE) && defined(CONFIG_MP)
 	spin = getenv("spin_table_compat");
diff --git a/arch/powerpc/cpu/mpc85xx/release.S b/arch/powerpc/cpu/mpc85xx/release.S
index a4a21b0..6af2efd 100644
--- a/arch/powerpc/cpu/mpc85xx/release.S
+++ b/arch/powerpc/cpu/mpc85xx/release.S
@@ -242,6 +242,21 @@ __secondary_start_page:
 2:
 #endif
 
+#ifdef CONFIG_SYS_FSL_ERRATUM_A005812
+	/*
+	 * A-005812 workaround sets bit 32 of SPR 976 for SoCs running in
+	 * write shadow mode. This code should run after other code setting
+	 * DCWS.
+	 */
+	mfspr	r3,L1CSR2
+	andis.	r3,r3,(L1CSR2_DCWS)@h
+	beq	1f
+	mfspr	r3, SPRN_HDBCR0
+	oris	r3, r3, 0x8000
+	mtspr	SPRN_HDBCR0, r3
+1:
+#endif
+
 #ifdef CONFIG_BACKSIDE_L2_CACHE
 	/* skip L2 setup on P2040/P2040E as they have no L2 */
 	mfspr	r3,SPRN_SVR
diff --git a/arch/powerpc/include/asm/config_mpc85xx.h b/arch/powerpc/include/asm/config_mpc85xx.h
index 057402b..9370a89 100644
--- a/arch/powerpc/include/asm/config_mpc85xx.h
+++ b/arch/powerpc/include/asm/config_mpc85xx.h
@@ -383,6 +383,7 @@
 #define CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY 0xf0000000
 #define CONFIG_SYS_FSL_ERRATUM_SRIO_A004034
 #define CONFIG_SYS_FSL_ERRATUM_A004849
+#define CONFIG_SYS_FSL_ERRATUM_A005812
 
 #elif defined(CONFIG_PPC_P4080) /* also supports P4040 */
 #define CONFIG_SYS_FSL_QORIQ_CHASSIS1
@@ -429,6 +430,7 @@
 #define CONFIG_SYS_FSL_ERRATUM_A004849
 #define CONFIG_SYS_FSL_ERRATUM_A004580
 #define CONFIG_SYS_P4080_ERRATUM_PCIE_A003
+#define CONFIG_SYS_FSL_ERRATUM_A005812
 
 #elif defined(CONFIG_PPC_P5020) /* also supports P5010 */
 #define CONFIG_SYS_PPC64		/* 64-bit core */
@@ -491,6 +493,7 @@
 #define CONFIG_SYS_FSL_ERRATUM_A004510
 #define CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV	0x10
 #define CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY 0xf0000000
+#define CONFIG_SYS_FSL_ERRATUM_A005812
 
 #elif defined(CONFIG_BSC9131)
 #define CONFIG_MAX_CPUS			1
-- 
1.7.9.5