diff options
| -rw-r--r-- | arch/arm/mach-vexpress/spc.c | 40 | ||||
| -rw-r--r-- | arch/arm/mach-vexpress/spc.h | 1 | ||||
| -rw-r--r-- | arch/arm/mach-vexpress/tc2_pm.c | 66 |
3 files changed, 102 insertions, 5 deletions
diff --git a/arch/arm/mach-vexpress/spc.c b/arch/arm/mach-vexpress/spc.c index 033d34dcbd3f..c26ef5b92ca7 100644 --- a/arch/arm/mach-vexpress/spc.c +++ b/arch/arm/mach-vexpress/spc.c @@ -53,6 +53,11 @@ #define A15_BX_ADDR0 0x68 #define A7_BX_ADDR0 0x78 +/* SPC CPU/cluster reset statue */ +#define STANDBYWFI_STAT 0x3c +#define STANDBYWFI_STAT_A15_CPU_MASK(cpu) (1 << (cpu)) +#define STANDBYWFI_STAT_A7_CPU_MASK(cpu) (1 << (3 + (cpu))) + /* SPC system config interface registers */ #define SYSCFG_WDATA 0x70 #define SYSCFG_RDATA 0x74 @@ -213,6 +218,41 @@ void ve_spc_powerdown(u32 cluster, bool enable) writel_relaxed(enable, info->baseaddr + pwdrn_reg); } +static u32 standbywfi_cpu_mask(u32 cpu, u32 cluster) +{ + return cluster_is_a15(cluster) ? + STANDBYWFI_STAT_A15_CPU_MASK(cpu) + : STANDBYWFI_STAT_A7_CPU_MASK(cpu); +} + +/** + * ve_spc_cpu_in_wfi(u32 cpu, u32 cluster) + * + * @cpu: mpidr[7:0] bitfield describing CPU affinity level within cluster + * @cluster: mpidr[15:8] bitfield describing cluster affinity level + * + * @return: non-zero if and only if the specified CPU is in WFI + * + * Take care when interpreting the result of this function: a CPU might + * be in WFI temporarily due to idle, and is not necessarily safely + * parked. + */ +int ve_spc_cpu_in_wfi(u32 cpu, u32 cluster) +{ + int ret; + u32 mask = standbywfi_cpu_mask(cpu, cluster); + + if (cluster >= MAX_CLUSTERS) + return 1; + + ret = readl_relaxed(info->baseaddr + STANDBYWFI_STAT); + + pr_debug("%s: PCFGREG[0x%X] = 0x%08X, mask = 0x%X\n", + __func__, STANDBYWFI_STAT, ret, mask); + + return ret & mask; +} + static int ve_spc_get_performance(int cluster, u32 *freq) { struct ve_spc_opp *opps = info->opps[cluster]; diff --git a/arch/arm/mach-vexpress/spc.h b/arch/arm/mach-vexpress/spc.h index dbd44c3720f9..793d065243b9 100644 --- a/arch/arm/mach-vexpress/spc.h +++ b/arch/arm/mach-vexpress/spc.h @@ -20,5 +20,6 @@ void ve_spc_global_wakeup_irq(bool set); void ve_spc_cpu_wakeup_irq(u32 cluster, u32 cpu, bool set); void ve_spc_set_resume_addr(u32 cluster, u32 cpu, u32 addr); void ve_spc_powerdown(u32 cluster, bool enable); +int ve_spc_cpu_in_wfi(u32 cpu, u32 cluster); #endif diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c index 05a364c5077a..29e7785a54bc 100644 --- a/arch/arm/mach-vexpress/tc2_pm.c +++ b/arch/arm/mach-vexpress/tc2_pm.c @@ -12,6 +12,7 @@ * published by the Free Software Foundation. */ +#include <linux/delay.h> #include <linux/init.h> #include <linux/io.h> #include <linux/kernel.h> @@ -32,11 +33,17 @@ #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; + /* * 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 @@ -190,6 +197,55 @@ static void tc2_pm_power_down(void) tc2_pm_down(0); } +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_power_down_finish(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) { + /* + * Only examine the hardware state if the target CPU has + * caught up at least as far as tc2_pm_down(): + */ + if (ACCESS_ONCE(tc2_pm_use_count[cpu][cluster]) == 0) { + 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_suspend(u64 residency) { unsigned int mpidr, cpu, cluster; @@ -232,10 +288,11 @@ static void tc2_pm_powered_up(void) } static const struct mcpm_platform_ops tc2_pm_power_ops = { - .power_up = tc2_pm_power_up, - .power_down = tc2_pm_power_down, - .suspend = tc2_pm_suspend, - .powered_up = tc2_pm_powered_up, + .power_up = tc2_pm_power_up, + .power_down = tc2_pm_power_down, + .power_down_finish = tc2_pm_power_down_finish, + .suspend = tc2_pm_suspend, + .powered_up = tc2_pm_powered_up, }; static bool __init tc2_pm_usage_count_init(void) @@ -269,7 +326,6 @@ static void __naked tc2_pm_power_up_setup(unsigned int affinity_level) static int __init tc2_pm_init(void) { int ret, irq; - void __iomem *scc; u32 a15_cluster_id, a7_cluster_id, sys_info; struct device_node *np; |