Re: [U-Boot] [PATCH] MIPS: Hang if run on a secondary CPU

On Wednesday, 21 September 2016 12:59:39 BST Langer, Thomas wrote:

Hello Paul,

...

diff --git a/arch/mips/cpu/start.S b/arch/mips/cpu/start.S index fc6dd66..dd37ac3 100644 --- a/arch/mips/cpu/start.S +++ b/arch/mips/cpu/start.S @@ -112,6 +112,31 @@ ENTRY(_start)

.align 4

reset: +#if __mips_isa_rev >= 6

• .set push
• .set reorder
• mfc0 t0, CP0_CONFIG, 1
• bgez t0, 1f
• mfc0 t0, CP0_CONFIG, 2
• bgez t0, 1f
• mfc0 t0, CP0_CONFIG, 3
• bgez t0, 1f
• mfc0 t0, CP0_CONFIG, 4
• bgez t0, 1f
• mfc0 t0, CP0_CONFIG, 5
• and t0, t0, MIPS_CONF5_VP
• beqz t0, 1f
• mfc0 t0, CP0_GLOBALNUMBER
• b 2f
• .set pop

+#endif

+1: mfc0 t0, CP0_EBASE

• and t0, t0, EBASE_CPUNUM
• /* Hang if this isn't the first CPU in the system */

+2: bnez t0, .

This loop should include a "wait" instruction. Otherwise the CPU will burn power for doing nothing.

Thomas

Hi Thomas,

True, it would spin until (typically) it gets reset by Linux or whatever OS is booted. I'll add a wait.

Thanks, Paul