On 07/26/2013 03:15 AM, Joseph Lo wrote: > The common LP1 resuming procedures of LP1 on Tegra was checking the LP1 > mask first. The LP1 mask indicated that the Tegra device was in LP1 then > we need to resume the Tegra from the LP1 reset handler. > > And the LP1 was putting the SDRAM to self-refresh mode, the SDRAM wasn't > accessible when resuming from LP1. We need to copy the LP1 reset handler > to IRAM before suspending. That's why you can see the address of LP1 > reset handler was located in IRAM.
That's rather hard to understand. How about: ========== Add support to the Tegra CPU reset vector to detect whether the CPU is resuming from LP1 suspend state. If it is, branch to the LP1-specific resume code. When Tegra enters the LP1 suspend state, the SDRAM controller is placed into a self-refresh state. For this reason, we must place the LP1 resume code into IRAM, so that it is accessible before SDRAM access has been re-enabled. ========== Talking about *copying* the LP1 resume code to IRAM isn't appropriate here, since nothing in this patch performs any copying of the resume code. > diff --git a/arch/arm/mach-tegra/reset-handler.S > b/arch/arm/mach-tegra/reset-handler.S > @@ -182,6 +182,19 @@ after_errata: > 1: > #endif > > + /* Waking up from LP1? */ > + ldr r8, [r12, #RESET_DATA(MASK_LP1)] > + tst r8, r11 @ if in_lp1 > + beq __is_not_lp1 > + cmp r10, #0 > + bne __die @ only CPU0 can be here > + ldr lr, [r12, #RESET_DATA(STARTUP_LP1)] > + THUMB( add lr, lr, #1 ) @ switch to Thumb mode > + cmp lr, #0 > + bleq __die @ no LP1 startup handler On thumb, lr==#1 at this point. I think you want to move the THUMB() instruction after the bleq. > diff --git a/arch/arm/mach-tegra/sleep.h b/arch/arm/mach-tegra/sleep.h > +#define TEGRA_IRAM_CODE_AREA (TEGRA_IRAM_BASE + SZ_4K) The layout of IRAM should be described in irammap.h not sleep.h. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
