1 files changed, 266 insertions, 0 deletions
diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
new file mode 100644
index 000000000..9b5f3c427
--- /dev/null
+++ b/arch/arm/mach-vexpress/tc2_pm.c
@@ -0,0 +1,266 @@
+/*
+ * arch/arm/mach-vexpress/tc2_pm.c - TC2 power management support
+ *
+ * Created by:	Nicolas Pitre, October 2012
+ * Copyright:	(C) 2012-2013  Linaro Limited
+ *
+ * Some portions of this file were originally written by Achin Gupta
+ * Copyright:   (C) 2012  ARM Limited
+ *
+ * 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/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/errno.h>
+#include <linux/irqchip/arm-gic.h>
+
+#include <asm/mcpm.h>
+#include <asm/proc-fns.h>
+#include <asm/cacheflush.h>
+#include <asm/cputype.h>
+#include <asm/cp15.h>
+
+#include <linux/arm-cci.h>
+
+#include "spc.h"
+
+/* SCC conf registers */
+#define RESET_CTRL		0x018
+#define RESET_A15_NCORERESET(cpu)	(1 << (2 + (cpu)))
+#define RESET_A7_NCORERESET(cpu)	(1 << (16 + (cpu)))
+
+#define A15_CONF		0x400
+#define A7_CONF			0x500
+#define SYS_INFO		0x700
+#define SPC_BASE		0xb00
+
+static void __iomem *scc;
+
+#define TC2_CLUSTERS			2
+#define TC2_MAX_CPUS_PER_CLUSTER	3
+
+static unsigned int tc2_nr_cpus[TC2_CLUSTERS];
+
+static int tc2_pm_cpu_powerup(unsigned int cpu, unsigned int cluster)
+{
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	if (cluster >= TC2_CLUSTERS || cpu >= tc2_nr_cpus[cluster])
+		return -EINVAL;
+	ve_spc_set_resume_addr(cluster, cpu,
+			       __pa_symbol(mcpm_entry_point));
+	ve_spc_cpu_wakeup_irq(cluster, cpu, true);
+	return 0;
+}
+
+static int tc2_pm_cluster_powerup(unsigned int cluster)
+{
+	pr_debug("%s: cluster %u\n", __func__, cluster);
+	if (cluster >= TC2_CLUSTERS)
+		return -EINVAL;
+	ve_spc_powerdown(cluster, false);
+	return 0;
+}
+
+static void tc2_pm_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster)
+{
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER);
+	ve_spc_cpu_wakeup_irq(cluster, cpu, true);
+	/*
+	 * If the CPU is committed to power down, make sure
+	 * the power controller will be in charge of waking it
+	 * up upon IRQ, ie IRQ lines are cut from GIC CPU IF
+	 * to the CPU by disabling the GIC CPU IF to prevent wfi
+	 * from completing execution behind power controller back
+	 */
+	gic_cpu_if_down(0);
+}
+
+static void tc2_pm_cluster_powerdown_prepare(unsigned int cluster)
+{
+	pr_debug("%s: cluster %u\n", __func__, cluster);
+	BUG_ON(cluster >= TC2_CLUSTERS);
+	ve_spc_powerdown(cluster, true);
+	ve_spc_global_wakeup_irq(true);
+}
+
+static void tc2_pm_cpu_cache_disable(void)
+{
+	v7_exit_coherency_flush(louis);
+}
+
+static void tc2_pm_cluster_cache_disable(void)
+{
+	if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A15) {
+		/*
+		 * On the Cortex-A15 we need to disable
+		 * L2 prefetching before flushing the cache.
+		 */
+		asm volatile(
+		"mcr	p15, 1, %0, c15, c0, 3 \n\t"
+		"isb	\n\t"
+		"dsb	"
+		: : "r" (0x400) );
+	}
+
+	v7_exit_coherency_flush(all);
+	cci_disable_port_by_cpu(read_cpuid_mpidr());
+}
+
+static int tc2_core_in_reset(unsigned int cpu, unsigned int cluster)
+{
+	u32 mask = cluster ?
+		  RESET_A7_NCORERESET(cpu)
+		: RESET_A15_NCORERESET(cpu);
+
+	return !(readl_relaxed(scc + RESET_CTRL) & mask);
+}
+
+#define POLL_MSEC 10
+#define TIMEOUT_MSEC 1000
+
+static int tc2_pm_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
+{
+	unsigned tries;
+
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER);
+
+	for (tries = 0; tries < TIMEOUT_MSEC / POLL_MSEC; ++tries) {
+		pr_debug("%s(cpu=%u, cluster=%u): RESET_CTRL = 0x%08X\n",
+			 __func__, cpu, cluster,
+			 readl_relaxed(scc + RESET_CTRL));
+
+		/*
+		 * We need the CPU to reach WFI, but the power
+		 * controller may put the cluster in reset and
+		 * power it off as soon as that happens, before
+		 * we have a chance to see STANDBYWFI.
+		 *
+		 * So we need to check for both conditions:
+		 */
+		if (tc2_core_in_reset(cpu, cluster) ||
+		    ve_spc_cpu_in_wfi(cpu, cluster))
+			return 0; /* success: the CPU is halted */
+
+		/* Otherwise, wait and retry: */
+		msleep(POLL_MSEC);
+	}
+
+	return -ETIMEDOUT; /* timeout */
+}
+
+static void tc2_pm_cpu_suspend_prepare(unsigned int cpu, unsigned int cluster)
+{
+	ve_spc_set_resume_addr(cluster, cpu, __pa_symbol(mcpm_entry_point));
+}
+
+static void tc2_pm_cpu_is_up(unsigned int cpu, unsigned int cluster)
+{
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER);
+	ve_spc_cpu_wakeup_irq(cluster, cpu, false);
+	ve_spc_set_resume_addr(cluster, cpu, 0);
+}
+
+static void tc2_pm_cluster_is_up(unsigned int cluster)
+{
+	pr_debug("%s: cluster %u\n", __func__, cluster);
+	BUG_ON(cluster >= TC2_CLUSTERS);
+	ve_spc_powerdown(cluster, false);
+	ve_spc_global_wakeup_irq(false);
+}
+
+static const struct mcpm_platform_ops tc2_pm_power_ops = {
+	.cpu_powerup		= tc2_pm_cpu_powerup,
+	.cluster_powerup	= tc2_pm_cluster_powerup,
+	.cpu_suspend_prepare	= tc2_pm_cpu_suspend_prepare,
+	.cpu_powerdown_prepare	= tc2_pm_cpu_powerdown_prepare,
+	.cluster_powerdown_prepare = tc2_pm_cluster_powerdown_prepare,
+	.cpu_cache_disable	= tc2_pm_cpu_cache_disable,
+	.cluster_cache_disable	= tc2_pm_cluster_cache_disable,
+	.wait_for_powerdown	= tc2_pm_wait_for_powerdown,
+	.cpu_is_up		= tc2_pm_cpu_is_up,
+	.cluster_is_up		= tc2_pm_cluster_is_up,
+};
+
+/*
+ * Enable cluster-level coherency, in preparation for turning on the MMU.
+ */
+static void __naked tc2_pm_power_up_setup(unsigned int affinity_level)
+{
+	asm volatile (" \n"
+"	cmp	r0, #1 \n"
+"	bxne	lr \n"
+"	b	cci_enable_port_for_self ");
+}
+
+static int __init tc2_pm_init(void)
+{
+	unsigned int mpidr, cpu, cluster;
+	int ret, irq;
+	u32 a15_cluster_id, a7_cluster_id, sys_info;
+	struct device_node *np;
+
+	/*
+	 * The power management-related features are hidden behind
+	 * SCC registers. We need to extract runtime information like
+	 * cluster ids and number of CPUs really available in clusters.
+	 */
+	np = of_find_compatible_node(NULL, NULL,
+			"arm,vexpress-scc,v2p-ca15_a7");
+	scc = of_iomap(np, 0);
+	if (!scc)
+		return -ENODEV;
+
+	a15_cluster_id = readl_relaxed(scc + A15_CONF) & 0xf;
+	a7_cluster_id = readl_relaxed(scc + A7_CONF) & 0xf;
+	if (a15_cluster_id >= TC2_CLUSTERS || a7_cluster_id >= TC2_CLUSTERS)
+		return -EINVAL;
+
+	sys_info = readl_relaxed(scc + SYS_INFO);
+	tc2_nr_cpus[a15_cluster_id] = (sys_info >> 16) & 0xf;
+	tc2_nr_cpus[a7_cluster_id] = (sys_info >> 20) & 0xf;
+
+	irq = irq_of_parse_and_map(np, 0);
+
+	/*
+	 * A subset of the SCC registers is also used to communicate
+	 * with the SPC (power controller). We need to be able to
+	 * drive it very early in the boot process to power up
+	 * processors, so we initialize the SPC driver here.
+	 */
+	ret = ve_spc_init(scc + SPC_BASE, a15_cluster_id, irq);
+	if (ret)
+		return ret;
+
+	if (!cci_probed())
+		return -ENODEV;
+
+	mpidr = read_cpuid_mpidr();
+	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	if (cluster >= TC2_CLUSTERS || cpu >= tc2_nr_cpus[cluster]) {
+		pr_err("%s: boot CPU is out of bound!\n", __func__);
+		return -EINVAL;
+	}
+
+	ret = mcpm_platform_register(&tc2_pm_power_ops);
+	if (!ret) {
+		mcpm_sync_init(tc2_pm_power_up_setup);
+		/* test if we can (re)enable the CCI on our own */
+		BUG_ON(mcpm_loopback(tc2_pm_cluster_cache_disable) != 0);
+		pr_info("TC2 power management initialized\n");
+	}
+	return ret;
+}
+
+early_initcall(tc2_pm_init);