[PATCH RFC/RFT 5/6] ARM: Exynos: migrate DCSCB to the new MCPM backend abstraction
Nicolas Pitre
nicolas.pitre at linaro.org
Tue Mar 24 16:24:30 PDT 2015
On Wed, 18 Mar 2015, Nicolas Pitre wrote:
> The custom suspend callback is removed for this change. That includes
> the dubious call to exynos_cpu_power_up(() that was present at the end
> of exynos_suspend().
After testing on actual hardware, it turns out that this call is
important. This patch is therefore amended with the following:
diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c
index d4bbbfb5fe..9bdf54795f 100644
--- a/arch/arm/mach-exynos/mcpm-exynos.c
+++ b/arch/arm/mach-exynos/mcpm-exynos.c
@@ -152,6 +152,12 @@ static int exynos_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
return -ETIMEDOUT; /* timeout */
}
+static void exynos_cpu_is_up(unsigned int cpu, unsigned int cluster)
+{
+ /* especially when resuming: make sure power control is set */
+ exynos_cpu_powerup(cpu, cluster);
+}
+
static const struct mcpm_platform_ops exynos_power_ops = {
.cpu_powerup = exynos_cpu_powerup,
.cluster_powerup = exynos_cluster_powerup,
@@ -160,6 +166,7 @@ static const struct mcpm_platform_ops exynos_power_ops = {
.cpu_cache_disable = exynos_cpu_cache_disable,
.cluster_cache_disable = exynos_cluster_cache_disable,
.wait_for_powerdown = exynos_wait_for_powerdown,
+ .cpu_is_up = exynos_cpu_is_up,
};
/*
The whole commit now appears as follows in my git tree:
commit 0d86b0b4cf869fa48d96bde231b9d04ea68b6422
Author: Nicolas Pitre <nicolas.pitre at linaro.org>
Date: Mon Mar 16 17:16:07 2015 -0400
ARM: Exynos: migrate DCSCB to the new MCPM backend abstraction
The custom suspend callback is removed for this change. The extra call
to exynos_cpu_power_up(() that was present at the end of exynos_suspend()
is now relocated to the cpu_is_up callback.
Signed-off-by: Nicolas Pitre <nico at linaro.org>
diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c
index b0d3c2e876..9bdf54795f 100644
--- a/arch/arm/mach-exynos/mcpm-exynos.c
+++ b/arch/arm/mach-exynos/mcpm-exynos.c
@@ -61,25 +61,7 @@ static void __iomem *ns_sram_base_addr;
: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", \
"r9", "r10", "lr", "memory")
-/*
- * 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 exynos_mcpm_lock = __ARCH_SPIN_LOCK_UNLOCKED;
-static int
-cpu_use_count[EXYNOS5420_CPUS_PER_CLUSTER][EXYNOS5420_NR_CLUSTERS];
-
-#define exynos_cluster_usecnt(cluster) \
- (cpu_use_count[0][cluster] + \
- cpu_use_count[1][cluster] + \
- cpu_use_count[2][cluster] + \
- cpu_use_count[3][cluster])
-
-#define exynos_cluster_unused(cluster) !exynos_cluster_usecnt(cluster)
-
-static int exynos_power_up(unsigned int cpu, unsigned int cluster)
+static int exynos_cpu_powerup(unsigned int cpu, unsigned int cluster)
{
unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
@@ -88,127 +70,65 @@ static int exynos_power_up(unsigned int cpu, unsigned int cluster)
cluster >= EXYNOS5420_NR_CLUSTERS)
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(&exynos_mcpm_lock);
-
- cpu_use_count[cpu][cluster]++;
- if (cpu_use_count[cpu][cluster] == 1) {
- bool was_cluster_down =
- (exynos_cluster_usecnt(cluster) == 1);
-
- /*
- * Turn on the cluster (L2/COMMON) and then power on the
- * cores.
- */
- if (was_cluster_down)
- exynos_cluster_power_up(cluster);
-
- exynos_cpu_power_up(cpunr);
- } else if (cpu_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();
- }
+ exynos_cpu_power_up(cpunr);
+ return 0;
+}
- arch_spin_unlock(&exynos_mcpm_lock);
- local_irq_enable();
+static int exynos_cluster_powerup(unsigned int cluster)
+{
+ pr_debug("%s: cluster %u\n", __func__, cluster);
+ if (cluster >= EXYNOS5420_NR_CLUSTERS)
+ return -EINVAL;
+ exynos_cluster_power_up(cluster);
return 0;
}
-/*
- * NOTE: This function requires the stack data to be visible through power down
- * and can only be executed on processors like A15 and A7 that hit the cache
- * with the C bit clear in the SCTLR register.
- */
-static void exynos_power_down(void)
+static void exynos_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster)
{
- unsigned int mpidr, cpu, cluster;
- bool last_man = false, skip_wfi = false;
- unsigned int cpunr;
-
- mpidr = read_cpuid_mpidr();
- cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
- cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
- cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
+ unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
cluster >= EXYNOS5420_NR_CLUSTERS);
+ exynos_cpu_power_down(cpunr);
+}
- __mcpm_cpu_going_down(cpu, cluster);
-
- arch_spin_lock(&exynos_mcpm_lock);
- BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
- cpu_use_count[cpu][cluster]--;
- if (cpu_use_count[cpu][cluster] == 0) {
- exynos_cpu_power_down(cpunr);
-
- if (exynos_cluster_unused(cluster)) {
- exynos_cluster_power_down(cluster);
- last_man = true;
- }
- } else if (cpu_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(&exynos_mcpm_lock);
-
- 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));
- }
+static void exynos_cluster_powerdown_prepare(unsigned int cluster)
+{
+ pr_debug("%s: cluster %u\n", __func__, cluster);
+ BUG_ON(cluster >= EXYNOS5420_NR_CLUSTERS);
+ exynos_cluster_power_down(cluster);
+}
- /* Flush all cache levels for this cluster. */
- exynos_v7_exit_coherency_flush(all);
+static void exynos_cpu_cache_disable(void)
+{
+ /* Disable and flush the local CPU cache. */
+ exynos_v7_exit_coherency_flush(louis);
+}
+static void exynos_cluster_cache_disable(void)
+{
+ if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A15) {
/*
- * Disable cluster-level coherency by masking
- * incoming snoops and DVM messages:
+ * On the Cortex-A15 we need to disable
+ * L2 prefetching before flushing the cache.
*/
- cci_disable_port_by_cpu(mpidr);
-
- __mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
- } else {
- arch_spin_unlock(&exynos_mcpm_lock);
-
- /* Disable and flush the local CPU cache. */
- exynos_v7_exit_coherency_flush(louis);
+ asm volatile(
+ "mcr p15, 1, %0, c15, c0, 3\n\t"
+ "isb\n\t"
+ "dsb"
+ : : "r" (0x400));
}
- __mcpm_cpu_down(cpu, cluster);
-
- /* Now we are prepared for power-down, do it: */
- if (!skip_wfi)
- wfi();
+ /* Flush all cache levels for this cluster. */
+ exynos_v7_exit_coherency_flush(all);
- /* Not dead at this point? Let our caller cope. */
+ /*
+ * Disable cluster-level coherency by masking
+ * incoming snoops and DVM messages:
+ */
+ cci_disable_port_by_cpu(read_cpuid_mpidr());
}
static int exynos_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
@@ -222,10 +142,8 @@ static int exynos_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
/* Wait for the core state to be OFF */
while (tries--) {
- if (ACCESS_ONCE(cpu_use_count[cpu][cluster]) == 0) {
- if ((exynos_cpu_power_state(cpunr) == 0))
- return 0; /* success: the CPU is halted */
- }
+ if ((exynos_cpu_power_state(cpunr) == 0))
+ return 0; /* success: the CPU is halted */
/* Otherwise, wait and retry: */
msleep(1);
@@ -234,63 +152,23 @@ static int exynos_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
return -ETIMEDOUT; /* timeout */
}
-static void exynos_powered_up(void)
-{
- unsigned int mpidr, cpu, cluster;
-
- mpidr = read_cpuid_mpidr();
- cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
- cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
-
- arch_spin_lock(&exynos_mcpm_lock);
- if (cpu_use_count[cpu][cluster] == 0)
- cpu_use_count[cpu][cluster] = 1;
- arch_spin_unlock(&exynos_mcpm_lock);
-}
-
-static void exynos_suspend(u64 residency)
+static void exynos_cpu_is_up(unsigned int cpu, unsigned int cluster)
{
- unsigned int mpidr, cpunr;
-
- exynos_power_down();
-
- /*
- * Execution reaches here only if cpu did not power down.
- * Hence roll back the changes done in exynos_power_down function.
- *
- * CAUTION: "This function requires the stack data to be visible through
- * power down and can only be executed on processors like A15 and A7
- * that hit the cache with the C bit clear in the SCTLR register."
- */
- mpidr = read_cpuid_mpidr();
- cpunr = exynos_pmu_cpunr(mpidr);
-
- exynos_cpu_power_up(cpunr);
+ /* especially when resuming: make sure power control is set */
+ exynos_cpu_powerup(cpu, cluster);
}
static const struct mcpm_platform_ops exynos_power_ops = {
- .power_up = exynos_power_up,
- .power_down = exynos_power_down,
+ .cpu_powerup = exynos_cpu_powerup,
+ .cluster_powerup = exynos_cluster_powerup,
+ .cpu_powerdown_prepare = exynos_cpu_powerdown_prepare,
+ .cluster_powerdown_prepare = exynos_cluster_powerdown_prepare,
+ .cpu_cache_disable = exynos_cpu_cache_disable,
+ .cluster_cache_disable = exynos_cluster_cache_disable,
.wait_for_powerdown = exynos_wait_for_powerdown,
- .suspend = exynos_suspend,
- .powered_up = exynos_powered_up,
+ .cpu_is_up = exynos_cpu_is_up,
};
-static void __init exynos_mcpm_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 >= EXYNOS5420_CPUS_PER_CLUSTER ||
- cluster >= EXYNOS5420_NR_CLUSTERS);
-
- cpu_use_count[cpu][cluster] = 1;
-}
-
/*
* Enable cluster-level coherency, in preparation for turning on the MMU.
*/
@@ -302,19 +180,6 @@ static void __naked exynos_pm_power_up_setup(unsigned int affinity_level)
"b cci_enable_port_for_self");
}
-static void __init exynos_cache_off(void)
-{
- if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A15) {
- /* disable L2 prefetching on the Cortex-A15 */
- asm volatile(
- "mcr p15, 1, %0, c15, c0, 3\n\t"
- "isb\n\t"
- "dsb"
- : : "r" (0x400));
- }
- exynos_v7_exit_coherency_flush(all);
-}
-
static const struct of_device_id exynos_dt_mcpm_match[] = {
{ .compatible = "samsung,exynos5420" },
{ .compatible = "samsung,exynos5800" },
@@ -370,13 +235,11 @@ static int __init exynos_mcpm_init(void)
*/
pmu_raw_writel(EXYNOS5420_SWRESET_KFC_SEL, S5P_PMU_SPARE3);
- exynos_mcpm_usage_count_init();
-
ret = mcpm_platform_register(&exynos_power_ops);
if (!ret)
ret = mcpm_sync_init(exynos_pm_power_up_setup);
if (!ret)
- ret = mcpm_loopback(exynos_cache_off); /* turn on the CCI */
+ ret = mcpm_loopback(exynos_cluster_cache_disable); /* turn on the CCI */
if (ret) {
iounmap(ns_sram_base_addr);
return ret;
Nicolas
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