diff options
Diffstat (limited to 'arch/arm/cpu/arm926ejs/spear/spl.c')
| -rw-r--r-- | arch/arm/cpu/arm926ejs/spear/spl.c | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/arch/arm/cpu/arm926ejs/spear/spl.c b/arch/arm/cpu/arm926ejs/spear/spl.c index b004cccafd..b2cacf2d3e 100644 --- a/arch/arm/cpu/arm926ejs/spear/spl.c +++ b/arch/arm/cpu/arm926ejs/spear/spl.c @@ -16,6 +16,12 @@ #include <asm/arch/spr_syscntl.h> #include <linux/mtd/st_smi.h> +/* Reserve some space to store the BootROM's stack pointer during SPL operation. + * The BSS cannot be used for this purpose because it will be zeroed after + * having stored the pointer, so force the location to the data section. + */ +u32 bootrom_stash_sp __attribute__((section(".data"))); + static void ddr_clock_init(void) { struct misc_regs *misc_p = (struct misc_regs *)CONFIG_SPEAR_MISCBASE; @@ -223,8 +229,9 @@ u32 spl_boot_device(void) { u32 mode = 0; - /* Currently only SNOR is supported as the only */ - if (snor_boot_selected()) { + if (usb_boot_selected()) { + mode = BOOT_DEVICE_BOOTROM; + } else if (snor_boot_selected()) { /* SNOR-SMI initialization */ snor_init(); @@ -252,3 +259,27 @@ void board_init_f(ulong dummy) mpmc_init(); spear_late_init(); } + +/* + * In a few cases (Ethernet, UART or USB boot, we might want to go back into the + * BootROM code right after having initialized a few components like the DRAM). + * The following function is called from SPL common code (board_init_r). + */ +void board_return_to_bootrom(void) +{ + /* + * Retrieve the BootROM's stack pointer and jump back to the start of + * the SPL, where we can easily branch back into the BootROM. Don't do + * it right here because SPL might be compiled in Thumb mode while the + * BootROM expects ARM mode. + */ + asm volatile ("ldr r0, =bootrom_stash_sp;" + "ldr r0, [r0];" + "mov sp, r0;" +#if defined(CONFIG_SPL_SYS_THUMB_BUILD) + "blx back_to_bootrom;" +#else + "bl back_to_bootrom;" +#endif + ); +} |