1 files changed, 221 insertions, 50 deletions

diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
index 445f30a2c5ef..9f59041a172b 100644
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -23,6 +23,7 @@
 #include <asm/cpuidle.h>
 #include <asm/code-patching.h>
 #include <asm/smp.h>
+#include <asm/runlatch.h>
 
 #include "powernv.h"
 #include "subcore.h"
@@ -30,8 +31,34 @@
 /* Power ISA 3.0 allows for stop states 0x0 - 0xF */
 #define MAX_STOP_STATE	0xF
 
+#define P9_STOP_SPR_MSR 2000
+#define P9_STOP_SPR_PSSCR      855
+
 static u32 supported_cpuidle_states;
 
+/*
+ * The default stop state that will be used by ppc_md.power_save
+ * function on platforms that support stop instruction.
+ */
+static u64 pnv_default_stop_val;
+static u64 pnv_default_stop_mask;
+static bool default_stop_found;
+
+/*
+ * First deep stop state. Used to figure out when to save/restore
+ * hypervisor context.
+ */
+u64 pnv_first_deep_stop_state = MAX_STOP_STATE;
+
+/*
+ * psscr value and mask of the deepest stop idle state.
+ * Used when a cpu is offlined.
+ */
+static u64 pnv_deepest_stop_psscr_val;
+static u64 pnv_deepest_stop_psscr_mask;
+static u64 pnv_deepest_stop_flag;
+static bool deepest_stop_found;
+
 static int pnv_save_sprs_for_deep_states(void)
 {
 	int cpu;
@@ -42,12 +69,14 @@ static int pnv_save_sprs_for_deep_states(void)
 	 * all cpus at boot. Get these reg values of current cpu and use the
 	 * same across all cpus.
 	 */
-	uint64_t lpcr_val = mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1;
+	uint64_t lpcr_val = mfspr(SPRN_LPCR);
 	uint64_t hid0_val = mfspr(SPRN_HID0);
 	uint64_t hid1_val = mfspr(SPRN_HID1);
 	uint64_t hid4_val = mfspr(SPRN_HID4);
 	uint64_t hid5_val = mfspr(SPRN_HID5);
 	uint64_t hmeer_val = mfspr(SPRN_HMEER);
+	uint64_t msr_val = MSR_IDLE;
+	uint64_t psscr_val = pnv_deepest_stop_psscr_val;
 
 	for_each_possible_cpu(cpu) {
 		uint64_t pir = get_hard_smp_processor_id(cpu);
@@ -61,6 +90,18 @@ static int pnv_save_sprs_for_deep_states(void)
 		if (rc != 0)
 			return rc;
 
+		if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+			rc = opal_slw_set_reg(pir, P9_STOP_SPR_MSR, msr_val);
+			if (rc)
+				return rc;
+
+			rc = opal_slw_set_reg(pir,
+					      P9_STOP_SPR_PSSCR, psscr_val);
+
+			if (rc)
+				return rc;
+		}
+
 		/* HIDs are per core registers */
 		if (cpu_thread_in_core(cpu) == 0) {
 
@@ -72,17 +113,21 @@ static int pnv_save_sprs_for_deep_states(void)
 			if (rc != 0)
 				return rc;
 
-			rc = opal_slw_set_reg(pir, SPRN_HID1, hid1_val);
-			if (rc != 0)
-				return rc;
+			/* Only p8 needs to set extra HID regiters */
+			if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
 
-			rc = opal_slw_set_reg(pir, SPRN_HID4, hid4_val);
-			if (rc != 0)
-				return rc;
+				rc = opal_slw_set_reg(pir, SPRN_HID1, hid1_val);
+				if (rc != 0)
+					return rc;
 
-			rc = opal_slw_set_reg(pir, SPRN_HID5, hid5_val);
-			if (rc != 0)
-				return rc;
+				rc = opal_slw_set_reg(pir, SPRN_HID4, hid4_val);
+				if (rc != 0)
+					return rc;
+
+				rc = opal_slw_set_reg(pir, SPRN_HID5, hid5_val);
+				if (rc != 0)
+					return rc;
+			}
 		}
 	}
 
@@ -96,15 +141,24 @@ static void pnv_alloc_idle_core_states(void)
 	u32 *core_idle_state;
 
 	/*
-	 * core_idle_state - First 8 bits track the idle state of each thread
-	 * of the core. The 8th bit is the lock bit. Initially all thread bits
-	 * are set. They are cleared when the thread enters deep idle state
-	 * like sleep and winkle. Initially the lock bit is cleared.
-	 * The lock bit has 2 purposes
-	 * a. While the first thread is restoring core state, it prevents
-	 * other threads in the core from switching to process context.
-	 * b. While the last thread in the core is saving the core state, it
-	 * prevents a different thread from waking up.
+	 * core_idle_state - The lower 8 bits track the idle state of
+	 * each thread of the core.
+	 *
+	 * The most significant bit is the lock bit.
+	 *
+	 * Initially all the bits corresponding to threads_per_core
+	 * are set. They are cleared when the thread enters deep idle
+	 * state like sleep and winkle/stop.
+	 *
+	 * Initially the lock bit is cleared.  The lock bit has 2
+	 * purposes:
+	 * 	a. While the first thread in the core waking up from
+	 * 	   idle is restoring core state, it prevents other
+	 * 	   threads in the core from switching to process
+	 * 	   context.
+	 * 	b. While the last thread in the core is saving the
+	 *	   core state, it prevents a different thread from
+	 *	   waking up.
 	 */
 	for (i = 0; i < nr_cores; i++) {
 		int first_cpu = i * threads_per_core;
@@ -112,7 +166,7 @@ static void pnv_alloc_idle_core_states(void)
 		size_t paca_ptr_array_size;
 
 		core_idle_state = kmalloc_node(sizeof(u32), GFP_KERNEL, node);
-		*core_idle_state = PNV_CORE_IDLE_THREAD_BITS;
+		*core_idle_state = (1 << threads_per_core) - 1;
 		paca_ptr_array_size = (threads_per_core *
 				       sizeof(struct paca_struct *));
 
@@ -132,8 +186,40 @@ static void pnv_alloc_idle_core_states(void)
 
 	update_subcore_sibling_mask();
 
-	if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT)
-		pnv_save_sprs_for_deep_states();
+	if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT) {
+		int rc = pnv_save_sprs_for_deep_states();
+
+		if (likely(!rc))
+			return;
+
+		/*
+		 * The stop-api is unable to restore hypervisor
+		 * resources on wakeup from platform idle states which
+		 * lose full context. So disable such states.
+		 */
+		supported_cpuidle_states &= ~OPAL_PM_LOSE_FULL_CONTEXT;
+		pr_warn("cpuidle-powernv: Disabling idle states that lose full context\n");
+		pr_warn("cpuidle-powernv: Idle power-savings, CPU-Hotplug affected\n");
+
+		if (cpu_has_feature(CPU_FTR_ARCH_300) &&
+		    (pnv_deepest_stop_flag & OPAL_PM_LOSE_FULL_CONTEXT)) {
+			/*
+			 * Use the default stop state for CPU-Hotplug
+			 * if available.
+			 */
+			if (default_stop_found) {
+				pnv_deepest_stop_psscr_val =
+					pnv_default_stop_val;
+				pnv_deepest_stop_psscr_mask =
+					pnv_default_stop_mask;
+				pr_warn("cpuidle-powernv: Offlined CPUs will stop with psscr = 0x%016llx\n",
+					pnv_deepest_stop_psscr_val);
+			} else { /* Fallback to snooze loop for CPU-Hotplug */
+				deepest_stop_found = false;
+				pr_warn("cpuidle-powernv: Offlined CPUs will busy wait\n");
+			}
+		}
+	}
 }
 
 u32 pnv_get_supported_cpuidle_states(void)
@@ -231,56 +317,127 @@ static DEVICE_ATTR(fastsleep_workaround_applyonce, 0600,
 			show_fastsleep_workaround_applyonce,
 			store_fastsleep_workaround_applyonce);
 
-/*
- * The default stop state that will be used by ppc_md.power_save
- * function on platforms that support stop instruction.
- */
-static u64 pnv_default_stop_val;
-static u64 pnv_default_stop_mask;
-static bool default_stop_found;
+static unsigned long __power7_idle_type(unsigned long type)
+{
+	unsigned long srr1;
+
+	if (!prep_irq_for_idle_irqsoff())
+		return 0;
+
+	__ppc64_runlatch_off();
+	srr1 = power7_idle_insn(type);
+	__ppc64_runlatch_on();
+
+	fini_irq_for_idle_irqsoff();
+
+	return srr1;
+}
+
+void power7_idle_type(unsigned long type)
+{
+	unsigned long srr1;
+
+	srr1 = __power7_idle_type(type);
+	irq_set_pending_from_srr1(srr1);
+}
+
+void power7_idle(void)
+{
+	if (!powersave_nap)
+		return;
+
+	power7_idle_type(PNV_THREAD_NAP);
+}
+
+static unsigned long __power9_idle_type(unsigned long stop_psscr_val,
+				      unsigned long stop_psscr_mask)
+{
+	unsigned long psscr;
+	unsigned long srr1;
+
+	if (!prep_irq_for_idle_irqsoff())
+		return 0;
+
+	psscr = mfspr(SPRN_PSSCR);
+	psscr = (psscr & ~stop_psscr_mask) | stop_psscr_val;
+
+	__ppc64_runlatch_off();
+	srr1 = power9_idle_stop(psscr);
+	__ppc64_runlatch_on();
+
+	fini_irq_for_idle_irqsoff();
+
+	return srr1;
+}
+
+void power9_idle_type(unsigned long stop_psscr_val,
+				      unsigned long stop_psscr_mask)
+{
+	unsigned long srr1;
+
+	srr1 = __power9_idle_type(stop_psscr_val, stop_psscr_mask);
+	irq_set_pending_from_srr1(srr1);
+}
 
 /*
  * Used for ppc_md.power_save which needs a function with no parameters
  */
-static void power9_idle(void)
+void power9_idle(void)
 {
-	power9_idle_stop(pnv_default_stop_val, pnv_default_stop_mask);
+	power9_idle_type(pnv_default_stop_val, pnv_default_stop_mask);
 }
 
-/*
- * First deep stop state. Used to figure out when to save/restore
- * hypervisor context.
- */
-u64 pnv_first_deep_stop_state = MAX_STOP_STATE;
+#ifdef CONFIG_HOTPLUG_CPU
+static void pnv_program_cpu_hotplug_lpcr(unsigned int cpu, u64 lpcr_val)
+{
+	u64 pir = get_hard_smp_processor_id(cpu);
 
-/*
- * psscr value and mask of the deepest stop idle state.
- * Used when a cpu is offlined.
- */
-static u64 pnv_deepest_stop_psscr_val;
-static u64 pnv_deepest_stop_psscr_mask;
-static bool deepest_stop_found;
+	mtspr(SPRN_LPCR, lpcr_val);
+	opal_slw_set_reg(pir, SPRN_LPCR, lpcr_val);
+}
 
 /*
  * pnv_cpu_offline: A function that puts the CPU into the deepest
  * available platform idle state on a CPU-Offline.
+ * interrupts hard disabled and no lazy irq pending.
  */
 unsigned long pnv_cpu_offline(unsigned int cpu)
 {
 	unsigned long srr1;
-
 	u32 idle_states = pnv_get_supported_cpuidle_states();
+	u64 lpcr_val;
+
+	/*
+	 * We don't want to take decrementer interrupts while we are
+	 * offline, so clear LPCR:PECE1. We keep PECE2 (and
+	 * LPCR_PECE_HVEE on P9) enabled as to let IPIs in.
+	 *
+	 * If the CPU gets woken up by a special wakeup, ensure that
+	 * the SLW engine sets LPCR with decrementer bit cleared, else
+	 * the CPU will come back to the kernel due to a spurious
+	 * wakeup.
+	 */
+	lpcr_val = mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1;
+	pnv_program_cpu_hotplug_lpcr(cpu, lpcr_val);
+
+	__ppc64_runlatch_off();
 
 	if (cpu_has_feature(CPU_FTR_ARCH_300) && deepest_stop_found) {
-		srr1 = power9_idle_stop(pnv_deepest_stop_psscr_val,
-					pnv_deepest_stop_psscr_mask);
-	} else if (idle_states & OPAL_PM_WINKLE_ENABLED) {
-		srr1 = power7_winkle();
+		unsigned long psscr;
+
+		psscr = mfspr(SPRN_PSSCR);
+		psscr = (psscr & ~pnv_deepest_stop_psscr_mask) |
+						pnv_deepest_stop_psscr_val;
+		srr1 = power9_idle_stop(psscr);
+
+	} else if ((idle_states & OPAL_PM_WINKLE_ENABLED) &&
+		   (idle_states & OPAL_PM_LOSE_FULL_CONTEXT)) {
+		srr1 = power7_idle_insn(PNV_THREAD_WINKLE);
 	} else if ((idle_states & OPAL_PM_SLEEP_ENABLED) ||
 		   (idle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
-		srr1 = power7_sleep();
+		srr1 = power7_idle_insn(PNV_THREAD_SLEEP);
 	} else if (idle_states & OPAL_PM_NAP_ENABLED) {
-		srr1 = power7_nap(1);
+		srr1 = power7_idle_insn(PNV_THREAD_NAP);
 	} else {
 		/* This is the fallback method. We emulate snooze */
 		while (!generic_check_cpu_restart(cpu)) {
@@ -291,8 +448,21 @@ unsigned long pnv_cpu_offline(unsigned int cpu)
 		HMT_medium();
 	}
 
+	__ppc64_runlatch_on();
+
+	/*
+	 * Re-enable decrementer interrupts in LPCR.
+	 *
+	 * Further, we want stop states to be woken up by decrementer
+	 * for non-hotplug cases. So program the LPCR via stop api as
+	 * well.
+	 */
+	lpcr_val = mfspr(SPRN_LPCR) | (u64)LPCR_PECE1;
+	pnv_program_cpu_hotplug_lpcr(cpu, lpcr_val);
+
 	return srr1;
 }
+#endif
 
 /*
  * Power ISA 3.0 idle initialization.
@@ -449,6 +619,7 @@ static int __init pnv_power9_idle_init(struct device_node *np, u32 *flags,
 			max_residency_ns = residency_ns[i];
 			pnv_deepest_stop_psscr_val = psscr_val[i];
 			pnv_deepest_stop_psscr_mask = psscr_mask[i];
+			pnv_deepest_stop_flag = flags[i];
 			deepest_stop_found = true;
 		}