For ARMv7-A architecture, the valid ISB instruction is asm volatile("isb").
This patch fixes the U-Boot was stuck in invalidate_dcache_all() before booting linux kernel, which occurred on rk3288-base development board such as evb-rk3288, rock2-rk3288. And something output via console like:
=> bootz 0x2000000 0x02000000 ramdisk start = 0x00000000, ramdisk end = 0x00000000 Continuing to boot without FDT Initial value for argc=3 Final value for argc=3 using: ATAGS
Starting kernel ...
Linux kernel exactly the same way(see arch/arm/include/asm/barrier.h).
Signed-off-by: Ziyuan Xu xzy.xu@rock-chips.com ---
arch/arm/include/asm/system.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index 2bdc0be..12d4ba0 100644 --- a/arch/arm/include/asm/system.h +++ b/arch/arm/include/asm/system.h @@ -227,13 +227,15 @@ void __noreturn psci_system_reset(bool smc); */ void save_boot_params_ret(void);
-#define isb() __asm__ __volatile__ ("" : : : "memory") - #define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");
#ifdef __ARM_ARCH_7A__ +#define isb() __asm__ __volatile__ ("isb" : : : "memory") + #define wfi() __asm__ __volatile__ ("wfi" : : : "memory") #else +#define isb() __asm__ __volatile__ ("" : : : "memory") + #define wfi() #endif