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authorJon Medhurst <tixy@linaro.org>2013-05-03 14:24:38 +0100
committerJon Medhurst <tixy@linaro.org>2013-05-03 14:24:38 +0100
commitc65283a962e8e391283db37939f8483249b0d276 (patch)
tree3934cce1e78da41ec9e55b70c7114b9ef212be5c /arch/arm/mach-vexpress/dcscb.c
parent84b4b2e12997f29a0c1890fcb700111a905ee6ad (diff)
parent23c5ac41ee7db68b1d64e75e641f026e8f1afe97 (diff)
downloadvexpress-lsk-c65283a962e8e391283db37939f8483249b0d276.tar.gz
Merge branch 'tracking-armlt-dcscb' into integration-linux-vexpress
Diffstat (limited to 'arch/arm/mach-vexpress/dcscb.c')
-rw-r--r--arch/arm/mach-vexpress/dcscb.c256
1 files changed, 256 insertions, 0 deletions
diff --git a/arch/arm/mach-vexpress/dcscb.c b/arch/arm/mach-vexpress/dcscb.c
new file mode 100644
index 00000000000..0dc3caca227
--- /dev/null
+++ b/arch/arm/mach-vexpress/dcscb.c
@@ -0,0 +1,256 @@
+/*
+ * arch/arm/mach-vexpress/dcscb.c - Dual Cluster System Configuration Block
+ *
+ * Created by: Nicolas Pitre, May 2012
+ * Copyright: (C) 2012-2013 Linaro 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/init.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/spinlock.h>
+#include <linux/errno.h>
+#include <linux/of_address.h>
+#include <linux/vexpress.h>
+#include <linux/arm-cci.h>
+
+#include <asm/mcpm.h>
+#include <asm/proc-fns.h>
+#include <asm/cacheflush.h>
+#include <asm/cputype.h>
+#include <asm/cp15.h>
+#include <asm/psci.h>
+
+
+#define RST_HOLD0 0x0
+#define RST_HOLD1 0x4
+#define SYS_SWRESET 0x8
+#define RST_STAT0 0xc
+#define RST_STAT1 0x10
+#define EAG_CFG_R 0x20
+#define EAG_CFG_W 0x24
+#define KFC_CFG_R 0x28
+#define KFC_CFG_W 0x2c
+#define DCS_CFG_R 0x30
+
+/*
+ * We can't use regular spinlocks. In the switcher case, it is possible
+ * for an outbound CPU to call power_down() after its inbound counterpart
+ * is already live using the same logical CPU number which trips lockdep
+ * debugging.
+ */
+static arch_spinlock_t dcscb_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+
+static void __iomem *dcscb_base;
+static int dcscb_use_count[4][2];
+static int dcscb_mcpm_cpu_mask[2];
+
+static int dcscb_power_up(unsigned int cpu, unsigned int cluster)
+{
+ unsigned int rst_hold, cpumask = (1 << cpu);
+ unsigned int mcpm_mask = dcscb_mcpm_cpu_mask[cluster];
+
+ pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+ if (cpu >= 4 || cluster >= 2)
+ return -EINVAL;
+
+ /*
+ * Since this is called with IRQs enabled, and no arch_spin_lock_irq
+ * variant exists, we need to disable IRQs manually here.
+ */
+ local_irq_disable();
+ arch_spin_lock(&dcscb_lock);
+
+ dcscb_use_count[cpu][cluster]++;
+ if (dcscb_use_count[cpu][cluster] == 1) {
+ rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
+ if (rst_hold & (1 << 8)) {
+ /* remove cluster reset and add individual CPU's reset */
+ rst_hold &= ~(1 << 8);
+ rst_hold |= mcpm_mask;
+ }
+ rst_hold &= ~(cpumask | (cpumask << 4));
+ writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
+ } else if (dcscb_use_count[cpu][cluster] != 2) {
+ /*
+ * The only possible values are:
+ * 0 = CPU down
+ * 1 = CPU (still) up
+ * 2 = CPU requested to be up before it had a chance
+ * to actually make itself down.
+ * Any other value is a bug.
+ */
+ BUG();
+ }
+
+ arch_spin_unlock(&dcscb_lock);
+ local_irq_enable();
+
+ return 0;
+}
+
+static void dcscb_power_down(void)
+{
+ unsigned int mpidr, cpu, cluster, rst_hold, cpumask, mcpm_mask;
+ bool last_man = false, skip_wfi = false;
+
+ mpidr = read_cpuid_mpidr();
+ cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+ cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+ cpumask = (1 << cpu);
+ mcpm_mask = dcscb_mcpm_cpu_mask[cluster];
+
+ pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+ BUG_ON(cpu >= 4 || cluster >= 2);
+
+ __mcpm_cpu_going_down(cpu, cluster);
+
+ arch_spin_lock(&dcscb_lock);
+ BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
+ dcscb_use_count[cpu][cluster]--;
+ if (dcscb_use_count[cpu][cluster] == 0) {
+ rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
+ rst_hold |= cpumask;
+ if (((rst_hold | (rst_hold >> 4)) & mcpm_mask) == mcpm_mask) {
+ rst_hold |= (1 << 8);
+ last_man = true;
+ }
+ writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
+ } else if (dcscb_use_count[cpu][cluster] == 1) {
+ /*
+ * A power_up request went ahead of us.
+ * Even if we do not want to shut this CPU down,
+ * the caller expects a certain state as if the WFI
+ * was aborted. So let's continue with cache cleaning.
+ */
+ skip_wfi = true;
+ } else
+ BUG();
+
+ if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) {
+ arch_spin_unlock(&dcscb_lock);
+
+ /*
+ * Flush all cache levels for this cluster.
+ *
+ * A15/A7 can hit in the cache with SCTLR.C=0, so we don't need
+ * a preliminary flush here for those CPUs. At least, that's
+ * the theory -- without the extra flush, Linux explodes on
+ * RTSM (maybe not needed anymore, to be investigated).
+ */
+ flush_cache_all();
+ set_cr(get_cr() & ~CR_C);
+ flush_cache_all();
+
+ /*
+ * This is a harmless no-op. On platforms with a real
+ * outer cache this might either be needed or not,
+ * depending on where the outer cache sits.
+ */
+ outer_flush_all();
+
+ /* Disable local coherency by clearing the ACTLR "SMP" bit: */
+ set_auxcr(get_auxcr() & ~(1 << 6));
+
+ /*
+ * Disable cluster-level coherency by masking
+ * incoming snoops and DVM messages:
+ */
+ disable_cci(cluster);
+
+ __mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
+ } else {
+ arch_spin_unlock(&dcscb_lock);
+
+ /*
+ * Flush the local CPU cache.
+ *
+ * A15/A7 can hit in the cache with SCTLR.C=0, so we don't need
+ * a preliminary flush here for those CPUs. At least, that's
+ * the theory -- without the extra flush, Linux explodes on
+ * RTSM (maybe not needed anymore, to be investigated).
+ */
+ flush_cache_louis();
+ set_cr(get_cr() & ~CR_C);
+ flush_cache_louis();
+
+ /* Disable local coherency by clearing the ACTLR "SMP" bit: */
+ set_auxcr(get_auxcr() & ~(1 << 6));
+ }
+
+ __mcpm_cpu_down(cpu, cluster);
+
+ /* Now we are prepared for power-down, do it: */
+ if (!skip_wfi) {
+ dsb();
+ wfi();
+ }
+
+ /* Not dead at this point? Let our caller cope. */
+}
+
+static const struct mcpm_platform_ops dcscb_power_ops = {
+ .power_up = dcscb_power_up,
+ .power_down = dcscb_power_down,
+};
+
+static void __init dcscb_usage_count_init(void)
+{
+ unsigned int mpidr, cpu, cluster;
+
+ 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);
+ BUG_ON(cpu >= 4 || cluster >= 2);
+ dcscb_use_count[cpu][cluster] = 1;
+}
+
+extern void dcscb_power_up_setup(unsigned int affinity_level);
+
+static int __init dcscb_init(void)
+{
+ struct device_node *node;
+ unsigned int cfg;
+ int ret;
+
+ ret = psci_probe();
+ if (!ret) {
+ pr_debug("psci found. Aborting native init\n");
+ return -ENODEV;
+ }
+
+ node = of_find_compatible_node(NULL, NULL, "arm,rtsm,dcscb");
+ if (!node)
+ return -ENODEV;
+ dcscb_base= of_iomap(node, 0);
+ if (!dcscb_base)
+ return -EADDRNOTAVAIL;
+ cfg = readl_relaxed(dcscb_base + DCS_CFG_R);
+ dcscb_mcpm_cpu_mask[0] = (1 << (((cfg >> 16) >> (0 << 2)) & 0xf)) - 1;
+ dcscb_mcpm_cpu_mask[1] = (1 << (((cfg >> 16) >> (1 << 2)) & 0xf)) - 1;
+ dcscb_usage_count_init();
+
+ ret = mcpm_platform_register(&dcscb_power_ops);
+ if (!ret)
+ ret = mcpm_sync_init(dcscb_power_up_setup);
+ if (ret) {
+ iounmap(dcscb_base);
+ return ret;
+ }
+
+ /*
+ * Future entries into the kernel can now go
+ * through the cluster entry vectors.
+ */
+ vexpress_flags_set(virt_to_phys(mcpm_entry_point));
+
+ return 0;
+}
+
+early_initcall(dcscb_init);