On Thu, Jun 30, 2016 at 04:51:48PM +0800, Gong Qianyu wrote:
From: Mingkai Hu mingkai.hu@nxp.com
Data coherency is enabled only when the CPUECTLR.SMPEN bit is set. The SMPEN bit should be set before enabling the data cache. If not enabled, the cache is not coherent with other cores and data corruption could occur.
Signed-off-by: Mingkai Hu mingkai.hu@nxp.com Signed-off-by: Gong Qianyu Qianyu.Gong@nxp.com
diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index 670e323..735dd67 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -81,6 +81,11 @@ reset: msr cpacr_el1, x0 /* Enable FP/SIMD */ 0:
- /* Enalbe SMPEN bit */
- mrs x0, S3_1_c15_c2_1 /* cpuactlr_el1 */
- orr x0, x0, #0x40
- msr S3_1_c15_c2_1, x0
Please note that this register is IMPLEMENTATION DEFINED, and not architectural, even though it happens to be common among ARM Ltd implementations.
This is also not something that one can usually set on the Non-secure side, and I'd expect Secure FW such as the ARM Trusted Firmware to handle this.
If this is necessary within U-Boot, it should be guarded such that it only runs on the relevant CPUs.
Thanks, Mark.