arm: K3: Avoid use of MCU_PSRAM0 before SYSFW is loaded

On HS devices the 512b region of reset isolated memory called
MCU_PSRAM0 is firewalled by default. Until SYSFW is loaded we
cannot use this memory. It is only used to store a single value
left at the end of SRAM by ROM that will be needed later. Save
that value to a global variable stored in the .data section.
This section is used as .bss will be cleared between saving
this value and using it.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Andreas Dannenberg <dannenberg@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>

diff --git a/arch/arm/mach-k3/am6_init.c b/arch/arm/mach-k3/am6_init.c
index 77cd15f388c40cb68b006dd27f9bd2d040ae3f53..60a580305df01d27e157d5696897fd748a436b92 100644 (file)
--- a/arch/arm/mach-k3/am6_init.c
+++ b/arch/arm/mach-k3/am6_init.c
@@ -49,11 +49,16 @@ static void ctrl_mmr_unlock(void)
        mmr_unlock(CTRL_MMR0_BASE, 7);
 }
 
+/*
+ * This uninitialized global variable would normal end up in the .bss section,
+ * but the .bss is cleared between writing and reading this variable, so move
+ * it to the .data section.
+ */
+u32 bootindex __attribute__((section(".data")));
+
 static void store_boot_index_from_rom(void)
 {
-       u32 *boot_index = (u32 *)K3_BOOT_PARAM_TABLE_INDEX_VAL;
-
-       *boot_index = *(u32 *)(CONFIG_SYS_K3_BOOT_PARAM_TABLE_INDEX);
+       bootindex = *(u32 *)(CONFIG_SYS_K3_BOOT_PARAM_TABLE_INDEX);
 }
 
 void board_init_f(ulong dummy)
@@ -92,7 +97,6 @@ u32 spl_boot_mode(const u32 boot_device)
 {
 #if defined(CONFIG_SUPPORT_EMMC_BOOT)
        u32 devstat = readl(CTRLMMR_MAIN_DEVSTAT);
-       u32 bootindex = readl(K3_BOOT_PARAM_TABLE_INDEX_VAL);
 
        u32 bootmode = (devstat & CTRLMMR_MAIN_DEVSTAT_BOOTMODE_MASK) >>
                        CTRLMMR_MAIN_DEVSTAT_BOOTMODE_SHIFT;
@@ -168,7 +172,6 @@ static u32 __get_primary_bootmedia(u32 devstat)
 u32 spl_boot_device(void)
 {
        u32 devstat = readl(CTRLMMR_MAIN_DEVSTAT);
-       u32 bootindex = readl(K3_BOOT_PARAM_TABLE_INDEX_VAL);
 
        if (bootindex == K3_PRIMARY_BOOTMODE)
                return __get_primary_bootmedia(devstat);

diff --git a/arch/arm/mach-k3/include/mach/am6_hardware.h b/arch/arm/mach-k3/include/mach/am6_hardware.h
index b5244609afafd0f1f0b42fdc2e6535cb6000f334..3343233aa3ca735becb81ac088405a2c147898c3 100644 (file)
--- a/arch/arm/mach-k3/include/mach/am6_hardware.h
+++ b/arch/arm/mach-k3/include/mach/am6_hardware.h
@@ -44,7 +44,4 @@
 #define CTRLMMR_LOCK_KICK1                             0x0100c
 #define CTRLMMR_LOCK_KICK1_UNLOCK_VAL                  0xd172bc5a
 
-/* MCU SCRATCHPAD usage */
-#define K3_BOOT_PARAM_TABLE_INDEX_VAL  CONFIG_SYS_K3_MCU_SCRATCHPAD_BASE
-
 #endif /* __ASM_ARCH_AM6_HARDWARE_H */