Re: [PATCH 14/25] OMAP4: PM: Add CPUX OFF mode support

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On Friday 09 September 2011 01:09 AM, Jean Pihet wrote:
On Sun, Sep 4, 2011 at 3:54 PM, Santosh Shilimkar
<santosh.shilimkar@xxxxxx>  wrote:
This patch adds the CPU0 and CPU1 off mode support. CPUX close switch
retention (CSWR) is not supported by hardware design.

The CPUx OFF mode isn't supported on OMAP4430 ES1.0

CPUx sleep code is common for hotplug, suspend and CPUilde.

Signed-off-by: Santosh Shilimkar<santosh.shilimkar@xxxxxx>
Cc: Kevin Hilman<khilman@xxxxxx>
---
  arch/arm/mach-omap2/Makefile                    |    3 +-
  arch/arm/mach-omap2/include/mach/omap-secure.h  |    8 +
  arch/arm/mach-omap2/include/mach/omap4-common.h |   25 +++
  arch/arm/mach-omap2/omap-mpuss-lowpower.c       |  249 +++++++++++++++++++++++
  arch/arm/mach-omap2/omap-smp.c                  |    6 +
  arch/arm/mach-omap2/omap4-sar-layout.h          |    9 +
  arch/arm/mach-omap2/pm44xx.c                    |    6 +
  arch/arm/mach-omap2/sleep44xx.S                 |  213 +++++++++++++++++++
  8 files changed, 518 insertions(+), 1 deletions(-)
  create mode 100644 arch/arm/mach-omap2/omap-mpuss-lowpower.c

diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
index b032c21..b4f2eeb 100644
--- a/arch/arm/mach-omap2/Makefile
+++ b/arch/arm/mach-omap2/Makefile
@@ -63,7 +63,8 @@ obj-$(CONFIG_ARCH_OMAP2)              += pm24xx.o
  obj-$(CONFIG_ARCH_OMAP2)               += sleep24xx.o
  obj-$(CONFIG_ARCH_OMAP3)               += pm34xx.o sleep34xx.o \
                                           cpuidle34xx.o
-obj-$(CONFIG_ARCH_OMAP4)               += pm44xx.o sleep44xx.o
+obj-$(CONFIG_ARCH_OMAP4)               += pm44xx.o sleep44xx.o \
+                                          omap-mpuss-lowpower.o
  obj-$(CONFIG_PM_DEBUG)                 += pm-debug.o
  obj-$(CONFIG_OMAP_SMARTREFLEX)          += sr_device.o smartreflex.o
  obj-$(CONFIG_OMAP_SMARTREFLEX_CLASS3)  += smartreflex-class3.o
diff --git a/arch/arm/mach-omap2/include/mach/omap-secure.h b/arch/arm/mach-omap2/include/mach/omap-secure.h
index e2f95a0..0062d49 100644
--- a/arch/arm/mach-omap2/include/mach/omap-secure.h
+++ b/arch/arm/mach-omap2/include/mach/omap-secure.h
@@ -35,10 +35,18 @@
  #define OMAP4_HAL_SAVEALL_INDEX                0x1c
  #define OMAP4_HAL_SAVEGIC_INDEX                0x1d

+/* Secure Monitor mode APIs */
+#define OMAP4_MON_SCU_PWR_INDEX                0x108
+
+/* Secure PPA(Primary Protected Application) APIs */
+#define OMAP4_PPA_CPU_ACTRL_SMP_INDEX  0x25
+
+#ifndef __ASSEMBLER__
  extern u32 omap_secure_dispatcher(u32 idx, u32 flag, u32 nargs,
                                u32 arg1, u32 arg2, u32 arg3, u32 arg4);
  extern u32 omap_smc2(u32 id, u32 falg, u32 pargs);
  extern phys_addr_t omap_secure_ram_mempool_base(void);
  extern int omap_secure_ram_reserve_memblock(void);

+#endif /* __ASSEMBLER__ */
  #endif /* OMAP_ARCH_OMAP_SECURE_H */
diff --git a/arch/arm/mach-omap2/include/mach/omap4-common.h b/arch/arm/mach-omap2/include/mach/omap4-common.h
index 040dcf6..662f37c 100644
--- a/arch/arm/mach-omap2/include/mach/omap4-common.h
+++ b/arch/arm/mach-omap2/include/mach/omap4-common.h
@@ -45,5 +45,30 @@ extern u32 omap_modify_auxcoreboot0(u32 set_mask, u32 clear_mask);
  extern void omap_auxcoreboot_addr(u32 cpu_addr);
  extern u32 omap_read_auxcoreboot0(void);
  #endif
+
+#if defined(CONFIG_SMP)&&  defined(CONFIG_PM)
+extern int omap4_mpuss_init(void);
+extern int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state);
+extern int omap4_finish_suspend(unsigned long cpu_state);
+extern void omap4_cpu_resume(void);
+#else
+static inline int omap4_enter_lowpower(unsigned int cpu,
+                                       unsigned int power_state)
+{
+       omap_do_wfi();
+       return 0;
+}
+
+static inline int omap4_mpuss_init(void)
+{
+       return 0;
+}
+
+static inline int omap4_finish_suspend(unsigned long cpu_state)
+{}
The int function should return something (0?)
Has the code been test compiled without SMP and/or PM?

+static inline void omap4_cpu_resume(void)
+{}
+#endif
+
  #endif /* __ASSEMBLER__ */
  #endif /* OMAP_ARCH_OMAP4_COMMON_H */
diff --git a/arch/arm/mach-omap2/omap-mpuss-lowpower.c b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
...

+/**
+ * omap4_enter_lowpower: OMAP4 MPUSS Low Power Entry Function
+ * The purpose of this function is to manage low power programming
+ * of OMAP4 MPUSS subsystem
+ * @cpu : CPU ID
+ * @power_state: Low power state.
+ */
+int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
+{
+       unsigned int save_state = 0;
+       unsigned int wakeup_cpu;
+
+       if (omap_rev() == OMAP4430_REV_ES1_0)
+               return -ENXIO;
+
+       switch (power_state) {
+       case PWRDM_POWER_ON:
+       case PWRDM_POWER_INACTIVE:
+               save_state = 0;
+               break;
+       case PWRDM_POWER_OFF:
+               save_state = 1;
+               break;
+       case PWRDM_POWER_RET:
+       default:
+               /*
+                * CPUx CSWR is invalid hardware state. Also CPUx OSWR
+                * doesn't make much scense, since logic is lost and $L1
+                * needs to be cleaned because of coherency. This makes
+                * CPUx OSWR equivalent to CPUX OFF and hence not supported
+                */
+               WARN_ON(1);
+               return -ENXIO;
+       }
+
+       clear_cpu_prev_pwrst(cpu);
+       set_cpu_next_pwrst(cpu, power_state);
+       set_cpu_wakeup_addr(cpu, virt_to_phys(omap4_cpu_resume));
+       scu_pwrst_prepare(cpu, power_state);
+
+       /*
+        * Call low level function  with targeted CPU id
+        * and its low power state.
+        */
+       cpu_suspend(save_state, omap4_finish_suspend);
There is no CPU id parameter to the call although the above comment says so.

...

diff --git a/arch/arm/mach-omap2/sleep44xx.S b/arch/arm/mach-omap2/sleep44xx.S
...

+/*
+ * =============================
+ * == CPU suspend finisher ==
+ * =============================
+ *
+ * void omap4_finish_suspend(unsigned long cpu_state)
+ *
+ * This function code saves the CPU context and performs the CPU
+ * power down sequence. Calling WFI effectively changes the CPU
+ * power domains states to the desired target power state.
+ *
+ * @cpu_state : contains context save state (r0)
+ *     0 - No context lost
+ *     1 - CPUx L1 and logic lost: MPUSS CSWR
+ *     2 - CPUx L1 and logic lost + GIC lost: MPUSS OSWR
+ *     3 - CPUx L1 and logic lost + GIC + L2 lost: MPUSS OFF
+ * @return: This function never returns for CPU OFF and DORMANT power states.
+ * Post WFI, CPU transitions to DORMANT or OFF power state and on wake-up
+ * from this follows a full CPU reset path via ROM code to CPU restore code.
Is the ROM code jumping to the physical address of omap4_cpu_resume?
If so please add it in the comment.

...

+/*
+ * ============================
+ * == CPU resume entry point ==
+ * ============================
+ *
+ * void omap4_cpu_resume(void)
+ *
+ * ROM code jumps to this function while waking up from CPU
+ * OFF or DORMANT state. Physical address of the function is
+ * stored in the SAR RAM while entering to OFF or DORMANT mode.
Which code stores the address in the SAR RAM? Please describe it here.

Will add that comment.

Regards
Santosh
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