Re: [v3,4/5] powerpc/pm: support deep sleep feature on T104x
From: C.H. Zhao
Date: Tue Sep 27 2016 - 17:15:57 EST
From: Scott Wood <oss@xxxxxxxxxxxx>
Sent: Sunday, September 25, 2016 3:24 PM
To: C.H. Zhao
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; z.chenhui@xxxxxxxxx; Jason Jin
Subject: Re: [v3,4/5] powerpc/pm: support deep sleep feature on T104x
On Tue, Aug 02, 2016 at 07:59:31PM +0800, Chenhui Zhao wrote:
> T104x has deep sleep feature, which can switch off most parts of
> the SoC when it is in deep sleep mode. This way, it becomes more
> energy-efficient.
>
> The DDR controller will also be powered off in deep sleep. Therefore,
> the last stage (the latter part of fsl_dp_enter_low) will run without DDR
> access. This piece of code and related TLBs are prefetched in advance.
>
> Due to the different initialization code between 32-bit and 64-bit, they
> have separate resume entry and precedure.
>
> The feature supports 32-bit and 64-bit kernel mode.
>
> Signed-off-by: Chenhui Zhao <chenhui.zhao@xxxxxxx>
> ---
> arch/powerpc/include/asm/fsl_pm.h | 24 ++
> arch/powerpc/kernel/asm-offsets.c | 12 +
> arch/powerpc/kernel/fsl_booke_entry_mapping.S | 10 +
> arch/powerpc/kernel/head_64.S | 2 +-
> arch/powerpc/platforms/85xx/Makefile | 1 +
> arch/powerpc/platforms/85xx/deepsleep.c | 278 ++++++++++++++
> arch/powerpc/platforms/85xx/qoriq_pm.c | 25 ++
> arch/powerpc/platforms/85xx/t104x_deepsleep.S | 531 ++++++++++++++++++++++++++
> arch/powerpc/sysdev/fsl_rcpm.c | 8 +-
> 9 files changed, 889 insertions(+), 2 deletions(-)
> create mode 100644 arch/powerpc/platforms/85xx/deepsleep.c
> create mode 100644 arch/powerpc/platforms/85xx/t104x_deepsleep.S
>
> diff --git a/arch/powerpc/include/asm/fsl_pm.h b/arch/powerpc/include/asm/fsl_pm.h
> index e05049b..48c2631 100644
> --- a/arch/powerpc/include/asm/fsl_pm.h
> +++ b/arch/powerpc/include/asm/fsl_pm.h
> @@ -20,6 +20,7 @@
>
> #define PLAT_PM_SLEEP 20
> #define PLAT_PM_LPM20 30
> +#define PLAT_PM_LPM35 40
>
> #define FSL_PM_SLEEP (1 << 0)
> #define FSL_PM_DEEP_SLEEP (1 << 1)
> @@ -48,4 +49,27 @@ extern const struct fsl_pm_ops *qoriq_pm_ops;
>
> int __init fsl_rcpm_init(void);
>
> +#ifdef CONFIG_FSL_QORIQ_PM
> +int fsl_enter_deepsleep(void);
> +int fsl_deepsleep_init(void);
> +#else
> +static inline int fsl_enter_deepsleep(void) { return -1; }
> +static inline int fsl_deepsleep_init(void) { return -1; }
> +#endif
Please return proper error codes.
Where can fsl_deepsleep_init() be called without CONFIG_FSL_QORIQ_PM?
[Chenhui] I can get rid of the ifdef here. And add it in arch/powerpc/sysdev/fsl_rcpm.c.
> +
> +extern void fsl_dp_enter_low(void *priv);
> +extern void fsl_booke_deep_sleep_resume(void);
> +
> +struct fsl_iomap {
> + void *ccsr_scfg_base;
> + void *ccsr_rcpm_base;
> + void *ccsr_ddr_base;
> + void *ccsr_gpio1_base;
> + void *ccsr_cpc_base;
> + void *dcsr_epu_base;
> + void *dcsr_npc_base;
> + void *dcsr_rcpm_base;
> + void *cpld_base;
> + void *fpga_base;
> +};
__iomem
[Chenhui] Yes. Will add it.
> #endif /* __PPC_FSL_PM_H */
> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
> index 9ea0955..cc488f9 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -68,6 +68,10 @@
> #include "../mm/mmu_decl.h"
> #endif
>
> +#ifdef CONFIG_FSL_QORIQ_PM
> +#include <asm/fsl_pm.h>
> +#endif
I know this file ifdefs headers a lot, but it's generally not good
practice. Does including this file cause any harm on other platforms?
[Chenhui] Not at all. Will remove it.
> diff --git a/arch/powerpc/kernel/fsl_booke_entry_mapping.S b/arch/powerpc/kernel/fsl_booke_entry_mapping.S
> index 83dd0f6..659b059 100644
> --- a/arch/powerpc/kernel/fsl_booke_entry_mapping.S
> +++ b/arch/powerpc/kernel/fsl_booke_entry_mapping.S
> @@ -173,6 +173,10 @@ skpinv: addi r6,r6,1 /* Increment */
> lis r6,MAS2_VAL(PAGE_OFFSET, BOOK3E_PAGESZ_64M, M_IF_NEEDED)@h
> ori r6,r6,MAS2_VAL(PAGE_OFFSET, BOOK3E_PAGESZ_64M, M_IF_NEEDED)@l
> mtspr SPRN_MAS2,r6
> +#ifdef ENTRY_DEEPSLEEP_SETUP
> + LOAD_REG_IMMEDIATE(r8, MEMORY_START)
> + ori r8,r8,(MAS3_SX|MAS3_SW|MAS3_SR)
> +#endif
> mtspr SPRN_MAS3,r8
> tlbwe
>
Have you tried this with a relocatable kernel?
[Chenhui] Not yet. Not sure whether it has been supported on QorIQ platform.
> +static void fsl_dp_set_resume_pointer(void)
> +{
> + u32 resume_addr;
> +
> + /* the bootloader will finally jump to this address to return kernel */
> +#ifdef CONFIG_PPC32
> + resume_addr = (u32)(__pa(fsl_booke_deep_sleep_resume));
> +#else
> + resume_addr = (u32)(__pa(*(u64 *)fsl_booke_deep_sleep_resume)
> + & 0xffffffff);
> +#endif
Why are you masking the physical address by 0xffffffff? Besides the
(u32) cast accomplishing the same thing, wouldn't it be a problem if
(e.g. due to a relocatable kernel) the address is above 4 GiB?
[Chenhui] Here, I assumed kernel is below 4 GiB. Maybe I should add a comment here.
> +static void fsl_dp_pins_setup(void)
> +{
> + u32 mask = BIT(31 - fsl_gpio_mcke);
> +
> + /* set GPIO1_29 as an output pin (not open-drain), and output 0 */
> + clrbits32(fsl_dp_priv.ccsr_gpio1_base + CCSR_GPIO1_GPDAT, mask);
> + clrbits32(fsl_dp_priv.ccsr_gpio1_base + CCSR_GPIO1_GPODR, mask);
> + setbits32(fsl_dp_priv.ccsr_gpio1_base + CCSR_GPIO1_GPDIR, mask);
> +
> + /* wait for the stabilization of GPIO1_29 */
> + udelay(10);
> +
> + /* enable the functionality of pins relevant to deep sleep */
> + if (fsl_dp_priv.cpld_base) {
> + setbits8(fsl_dp_priv.cpld_base + QORIQ_CPLD_MISCCSR,
> + QORIQ_CPLD_MISCCSR_SLEEPEN);
> + } else if (fsl_dp_priv.fpga_base) {
> + setbits8(fsl_dp_priv.fpga_base + QIXIS_PWR_CTL2,
> + QIXIS_PWR_CTL2_PCTL);
> + }
> +}
Please use callbacks to handle board-specific things.
[Chenhui] Yes. Will do it as you said.
> +/* reset time base to prevent from overflow */
> +#define DELAY(count) \
> + li r3, count; \
> + li r4, 0; \
> + mtspr SPRN_TBWL, r4; \
> +101: mfspr r4, SPRN_TBRL; \
> + cmpw r4, r3; \
> + blt 101b
Please find a better way of dealing with overflow than writing to the
timebase.
-Scott
[Chenhui] OK. Let me try other way. Thank you for your time.