ARM: OMAP4: PM: Add CPUX OFF mode support

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@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

1 files changed, 248 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/omap-mpuss-lowpower.c b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
new file mode 100644
index 000000000000..867fee51e42c
--- /dev/null
+++ b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
@@ -0,0 +1,248 @@
+/*
+ * OMAP MPUSS low power code
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ *	Santosh Shilimkar <santosh.shilimkar@ti.com>
+ *
+ * OMAP4430 MPUSS mainly consists of dual Cortex-A9 with per-CPU
+ * Local timer and Watchdog, GIC, SCU, PL310 L2 cache controller,
+ * CPU0 and CPU1 LPRM modules.
+ * CPU0, CPU1 and MPUSS each have there own power domain and
+ * hence multiple low power combinations of MPUSS are possible.
+ *
+ * The CPU0 and CPU1 can't support Closed switch Retention (CSWR)
+ * because the mode is not supported by hw constraints of dormant
+ * mode. While waking up from the dormant mode, a reset  signal
+ * to the Cortex-A9 processor must be asserted by the external
+ * power controller.
+ *
+ * With architectural inputs and hardware recommendations, only
+ * below modes are supported from power gain vs latency point of view.
+ *
+ *	CPU0		CPU1		MPUSS
+ *	----------------------------------------------
+ *	ON		ON		ON
+ *	ON(Inactive)	OFF		ON(Inactive)
+ *	OFF		OFF		CSWR
+ *	OFF		OFF		OSWR (*TBD)
+ *	OFF		OFF		OFF* (*TBD)
+ *	----------------------------------------------
+ *
+ * Note: CPU0 is the master core and it is the last CPU to go down
+ * and first to wake-up when MPUSS low power states are excercised
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/errno.h>
+#include <linux/linkage.h>
+#include <linux/smp.h>
+
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm/smp_scu.h>
+#include <asm/system.h>
+#include <asm/pgalloc.h>
+#include <asm/suspend.h>
+
+#include <plat/omap44xx.h>
+
+#include "common.h"
+#include "omap4-sar-layout.h"
+#include "pm.h"
+#include "powerdomain.h"
+
+#ifdef CONFIG_SMP
+
+struct omap4_cpu_pm_info {
+	struct powerdomain *pwrdm;
+	void __iomem *scu_sar_addr;
+	void __iomem *wkup_sar_addr;
+};
+
+static DEFINE_PER_CPU(struct omap4_cpu_pm_info, omap4_pm_info);
+
+/*
+ * Program the wakeup routine address for the CPU0 and CPU1
+ * used for OFF or DORMANT wakeup.
+ */
+static inline void set_cpu_wakeup_addr(unsigned int cpu_id, u32 addr)
+{
+	struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
+
+	__raw_writel(addr, pm_info->wkup_sar_addr);
+}
+
+/*
+ * Set the CPUx powerdomain's previous power state
+ */
+static inline void set_cpu_next_pwrst(unsigned int cpu_id,
+				unsigned int power_state)
+{
+	struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
+
+	pwrdm_set_next_pwrst(pm_info->pwrdm, power_state);
+}
+
+/*
+ * Read CPU's previous power state
+ */
+static inline unsigned int read_cpu_prev_pwrst(unsigned int cpu_id)
+{
+	struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
+
+	return pwrdm_read_prev_pwrst(pm_info->pwrdm);
+}
+
+/*
+ * Clear the CPUx powerdomain's previous power state
+ */
+static inline void clear_cpu_prev_pwrst(unsigned int cpu_id)
+{
+	struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
+
+	pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
+}
+
+/*
+ * Store the SCU power status value to scratchpad memory
+ */
+static void scu_pwrst_prepare(unsigned int cpu_id, unsigned int cpu_state)
+{
+	struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
+	u32 scu_pwr_st;
+
+	switch (cpu_state) {
+	case PWRDM_POWER_RET:
+		scu_pwr_st = SCU_PM_DORMANT;
+		break;
+	case PWRDM_POWER_OFF:
+		scu_pwr_st = SCU_PM_POWEROFF;
+		break;
+	case PWRDM_POWER_ON:
+	case PWRDM_POWER_INACTIVE:
+	default:
+		scu_pwr_st = SCU_PM_NORMAL;
+		break;
+	}
+
+	__raw_writel(scu_pwr_st, pm_info->scu_sar_addr);
+}
+
+/**
+ * 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 low power state.
+	 */
+	cpu_suspend(save_state, omap4_finish_suspend);
+
+	/*
+	 * Restore the CPUx power state to ON otherwise CPUx
+	 * power domain can transitions to programmed low power
+	 * state while doing WFI outside the low powe code. On
+	 * secure devices, CPUx does WFI which can result in
+	 * domain transition
+	 */
+	wakeup_cpu = smp_processor_id();
+	set_cpu_next_pwrst(wakeup_cpu, PWRDM_POWER_ON);
+
+	return 0;
+}
+
+/*
+ * Initialise OMAP4 MPUSS
+ */
+int __init omap4_mpuss_init(void)
+{
+	struct omap4_cpu_pm_info *pm_info;
+	void __iomem *sar_base = omap4_get_sar_ram_base();
+
+	if (omap_rev() == OMAP4430_REV_ES1_0) {
+		WARN(1, "Power Management not supported on OMAP4430 ES1.0\n");
+		return -ENODEV;
+	}
+
+	/* Initilaise per CPU PM information */
+	pm_info = &per_cpu(omap4_pm_info, 0x0);
+	pm_info->scu_sar_addr = sar_base + SCU_OFFSET0;
+	pm_info->wkup_sar_addr = sar_base + CPU0_WAKEUP_NS_PA_ADDR_OFFSET;
+	pm_info->pwrdm = pwrdm_lookup("cpu0_pwrdm");
+	if (!pm_info->pwrdm) {
+		pr_err("Lookup failed for CPU0 pwrdm\n");
+		return -ENODEV;
+	}
+
+	/* Clear CPU previous power domain state */
+	pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
+
+	/* Initialise CPU0 power domain state to ON */
+	pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
+
+	pm_info = &per_cpu(omap4_pm_info, 0x1);
+	pm_info->scu_sar_addr = sar_base + SCU_OFFSET1;
+	pm_info->wkup_sar_addr = sar_base + CPU1_WAKEUP_NS_PA_ADDR_OFFSET;
+	pm_info->pwrdm = pwrdm_lookup("cpu1_pwrdm");
+	if (!pm_info->pwrdm) {
+		pr_err("Lookup failed for CPU1 pwrdm\n");
+		return -ENODEV;
+	}
+
+	/* Clear CPU previous power domain state */
+	pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
+
+	/* Initialise CPU1 power domain state to ON */
+	pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
+
+	/* Save device type on scratchpad for low level code to use */
+	if (omap_type() != OMAP2_DEVICE_TYPE_GP)
+		__raw_writel(1, sar_base + OMAP_TYPE_OFFSET);
+	else
+		__raw_writel(0, sar_base + OMAP_TYPE_OFFSET);
+
+	return 0;
+}
+
+#endif