Thread (11 messages) 11 messages, 2 authors, 2016-10-03

Re: [v3,4/5] powerpc/pm: support deep sleep feature on T104x

From: Scott Wood <oss@buserror.net>
Date: 2016-09-25 07:24:11
Also in: lkml

On Tue, Aug 02, 2016 at 07:59:31PM +0800, Chenhui Zhao wrote:
quoted hunk ↗ jump to hunk
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 <redacted>
---
 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?
+
+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
quoted hunk ↗ jump to hunk
 #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?
quoted hunk ↗ jump to hunk
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?
+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?
+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.
+/* 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
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