[PATCH] arm: mach-k3: j721s2: j784s4: Add errata i2378 workaround

[Neha Malcom Francis]

The shadow copies of WAY_SELECT MSMC MMRs have incorrect reset values.
The main copy has the correct reset value but MSMC functionality uses
the shadow copy values. This incorrect reset value results in
under-utilization of MSMC L3 data cache and snoop filter for DDR
accesses.

The workaround is to write 0x00000303 to both MSMC MMRs after reset.
This ensures that their shadow copies get the correct post-reset value.

Link: https://www.ti.com/lit/er/sprz530c/sprz530c.pdf
Link: https://www.ti.com/lit/er/sprz536b/sprz536b.pdf
Signed-off-by: Neha Malcom Francis <n-francis at ti.com>
---
 arch/arm/mach-k3/include/mach/j721s2_hardware.h |  4 ++++
 arch/arm/mach-k3/include/mach/j784s4_hardware.h |  4 ++++
 arch/arm/mach-k3/j721s2/j721s2_init.c           | 11 +++++++++++
 arch/arm/mach-k3/j784s4/j784s4_init.c           | 11 +++++++++++
 4 files changed, 30 insertions(+)

diff --git a/arch/arm/mach-k3/include/mach/j721s2_hardware.h b/arch/arm/mach-k3/include/mach/j721s2_hardware.h
index 82f076a45e0..a4d7fe48662 100644
--- a/arch/arm/mach-k3/include/mach/j721s2_hardware.h
+++ b/arch/arm/mach-k3/include/mach/j721s2_hardware.h
@@ -37,6 +37,10 @@
 /* MCU SCRATCHPAD usage */
 #define TI_SRAM_SCRATCH_BOARD_EEPROM_START	CONFIG_SYS_K3_MCU_SCRATCHPAD_BASE
 
+/* MSMC RT_WAY MMR addresses */
+#define K3_MSMC_RT_WAY_SELECT		0x6E008000
+#define K3_MSMC_NRT_WAY_SELECT		0x6E008008
+
 #if defined(CONFIG_SYS_K3_SPL_ATF) && !defined(__ASSEMBLY__)
 
 #define J721S2_DEV_MCU_RTI0			295
diff --git a/arch/arm/mach-k3/include/mach/j784s4_hardware.h b/arch/arm/mach-k3/include/mach/j784s4_hardware.h
index 29a894baed3..bb5c58d00e4 100644
--- a/arch/arm/mach-k3/include/mach/j784s4_hardware.h
+++ b/arch/arm/mach-k3/include/mach/j784s4_hardware.h
@@ -37,6 +37,10 @@
 /* MCU SCRATCHPAD usage */
 #define TI_SRAM_SCRATCH_BOARD_EEPROM_START	CONFIG_SYS_K3_MCU_SCRATCHPAD_BASE
 
+/* MSMC RT_WAY MMR addresses */
+#define K3_MSMC_RT_WAY_SELECT		0x6E008000
+#define K3_MSMC_NRT_WAY_SELECT		0x6E008008
+
 #if defined(CONFIG_SYS_K3_SPL_ATF) && !defined(__ASSEMBLY__)
 
 #define J784S4_DEV_MCU_RTI0			367
diff --git a/arch/arm/mach-k3/j721s2/j721s2_init.c b/arch/arm/mach-k3/j721s2/j721s2_init.c
index b5453d8895d..d996dfcc332 100644
--- a/arch/arm/mach-k3/j721s2/j721s2_init.c
+++ b/arch/arm/mach-k3/j721s2/j721s2_init.c
@@ -163,6 +163,14 @@ static void store_boot_info_from_rom(void)
 	       sizeof(struct rom_extended_boot_data));
 }
 
+void apply_msmc_shadow_copy_errata(void)
+{
+	/* Errata i2378: Write 0x00000303 to MSMC shadow copy MMRs */
+	writel(0x00000303, K3_MSMC_RT_WAY_SELECT);
+	writel(0x00000303, K3_MSMC_NRT_WAY_SELECT);
+	debug("%s: Applied errata i2378\n", __func__);
+}
+
 void k3_spl_init(void)
 {
 	struct udevice *dev;
@@ -176,6 +184,9 @@ void k3_spl_init(void)
 	/* Make all control module registers accessible */
 	ctrl_mmr_unlock();
 
+	/* Apply MSMC shadow copy errata workaround */
+	apply_msmc_shadow_copy_errata();
+
 	if (IS_ENABLED(CONFIG_CPU_V7R)) {
 		disable_linefill_optimization();
 		setup_k3_mpu_regions();
diff --git a/arch/arm/mach-k3/j784s4/j784s4_init.c b/arch/arm/mach-k3/j784s4/j784s4_init.c
index 53f152ccd9c..48b52fcb333 100644
--- a/arch/arm/mach-k3/j784s4/j784s4_init.c
+++ b/arch/arm/mach-k3/j784s4/j784s4_init.c
@@ -180,6 +180,14 @@ static void store_boot_info_from_rom(void)
 	       sizeof(struct rom_extended_boot_data));
 }
 
+void apply_msmc_shadow_copy_errata(void)
+{
+	/* Errata i2378: Write 0x00000303 to MSMC shadow copy MMRs */
+	writel(0x00000303, K3_MSMC_RT_WAY_SELECT);
+	writel(0x00000303, K3_MSMC_NRT_WAY_SELECT);
+	debug("%s: Applied errata i2378\n", __func__);
+}
+
 void k3_spl_init(void)
 {
 	struct udevice *dev;
@@ -194,6 +202,9 @@ void k3_spl_init(void)
 	/* Make all control module registers accessible */
 	ctrl_mmr_unlock();
 
+	/* Apply MSMC shadow copy errata workaround */
+	apply_msmc_shadow_copy_errata();
+
 	if (IS_ENABLED(CONFIG_CPU_V7R)) {
 		disable_linefill_optimization();
 		setup_k3_mpu_regions();
-- 
2.34.1