<Tero.Kristo@xxxxxxxxx> writes: > > >>-----Original Message----- >>From: ext Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx] >>Sent: 13 August, 2009 17:17 >>To: Kristo Tero (Nokia-D/Tampere) >>Cc: linux-omap@xxxxxxxxxxxxxxx >>Subject: Re: [PATCH] PM OMAP3: Change omap3_save_secure_ram to >>be called only during init >> >>Tero Kristo <tero.kristo@xxxxxxxxx> writes: >> >>> This function is now called only once during the >>initialization of the device >>> and consequent sleep cycles will re-use the same saved >>contents for secure >>> RAM. Users who need secure services should do secure RAM >>saving before >>> entering off-mode, if a secure service has been accessed >>after last save. >>> Signed-off-by: Tero Kristo <tero.kristo@xxxxxxxxx> >> >>You explain what you're doing, but you don't explain why. >> >>Is there a large latency involved in this save/restore that you're >>trying to eliminate for the no-secure-services case? > > There are both latency and reliability issues. The context save uses a > hardware resource which takes an order of hundreds of milliseconds to > initialize after a wake up from off-mode, and also there is no way of > checking whether it is ready from kernel side or not. It just crashes > if you use it too quickly. Tero, OK, makes sense. Thanks or the clarification. I'll add this to the changelog and push to PM branch. Kevin >> >>Kevin >> >>> --- arch/arm/mach-omap2/pm34xx.c | 19 ++++++++++++++++++- 1 files >>> changed, 18 insertions(+), 1 deletions(-) >>> diff --git a/arch/arm/mach-omap2/pm34xx.c >>b/arch/arm/mach-omap2/pm34xx.c >>> index 4223622..b8cf5f2 100644 --- a/arch/arm/mach-omap2/pm34xx.c >>> +++ b/arch/arm/mach-omap2/pm34xx.c >>> @@ -127,6 +127,12 @@ static void omap3_core_restore_context(void) >>> omap_dma_global_context_restore(); } >>> >>> +/* * FIXME: This function should be called before entering >>off-mode after >>> + * OMAP3 secure services have been accessed. Currently it >>is only called >>> + * once during boot sequence, but this works as we are not >>using secure >>> + * services. */ >>> static void omap3_save_secure_ram_context(u32 target_mpu_state) { >>> u32 ret; @@ -349,7 +355,6 @@ void omap_sram_idle(void) >>> OMAP3_PRM_VOLTCTRL_OFFSET); omap3_core_save_context(); >>> omap3_prcm_save_context(); - >>> omap3_save_secure_ram_context(mpu_next_state); } /* Enable IO-PAD >>> wakeup */ prm_set_mod_reg_bits(OMAP3430_EN_IO, WKUP_MOD, PM_WKEN); >>> @@ -923,6 +928,18 @@ int __init omap3_pm_init(void) } >>> omap3_save_scratchpad_contents(); >>> >>> + if (omap_type() != OMAP2_DEVICE_TYPE_GP) { >>> + local_irq_disable(); >>> + local_fiq_disable(); >>> + >>> + omap_dma_global_context_save(); >>> + omap3_save_secure_ram_context(PWRDM_POWER_ON); >>> + omap_dma_global_context_restore(); >>> + >>> + local_irq_enable(); >>> + local_fiq_enable(); >>> + } >>> + >>> err1: return ret; err2: -- 1.5.4.3 >>> -- To unsubscribe from this list: send the line "unsubscribe >>linux-omap" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo >>> info at http://vger.kernel.org/majordomo-info.html >> -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
