From mboxrd@z Thu Jan 1 00:00:00 1970 From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi) Date: Fri, 5 Sep 2014 18:34:53 +0100 Subject: [PATCH v9 4/8] arm64: add PSCI CPU_SUSPEND based cpu_suspend support In-Reply-To: <1409938498-17984-1-git-send-email-lorenzo.pieralisi@arm.com> References: <1409938498-17984-1-git-send-email-lorenzo.pieralisi@arm.com> Message-ID: <1409938498-17984-5-git-send-email-lorenzo.pieralisi@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org This patch implements the cpu_suspend cpu operations method through the PSCI CPU SUSPEND API. The PSCI implementation translates the idle state index passed by the cpu_suspend core call into a valid PSCI state according to the PSCI states initialized at boot through the cpu_init_idle() CPU operations hook. The PSCI CPU suspend operation hook checks if the PSCI state is a standby state. If it is, it calls the PSCI suspend implementation straight away, without saving any context. If the state is a power down state the kernel calls the __cpu_suspend API (that saves the CPU context) and passed the PSCI suspend finisher as a parameter so that PSCI can be called by the __cpu_suspend implementation after saving and flushing the context as last function before power down. For power down states, entry point is set to cpu_resume physical address, that represents the default kernel execution address following a CPU reset. Reviewed-by: Ashwin Chaugule Reviewed-by: Catalin Marinas Signed-off-by: Lorenzo Pieralisi --- arch/arm64/kernel/psci.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c index 5539547..866c1c8 100644 --- a/arch/arm64/kernel/psci.c +++ b/arch/arm64/kernel/psci.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include @@ -28,6 +29,7 @@ #include #include #include +#include #include #define PSCI_POWER_STATE_TYPE_STANDBY 0 @@ -65,6 +67,8 @@ enum psci_function { PSCI_FN_MAX, }; +static DEFINE_PER_CPU_READ_MOSTLY(struct psci_power_state *, psci_power_state); + static u32 psci_function_id[PSCI_FN_MAX]; static int psci_to_linux_errno(int errno) @@ -93,6 +97,18 @@ static u32 psci_power_state_pack(struct psci_power_state state) & PSCI_0_2_POWER_STATE_AFFL_MASK); } +static void psci_power_state_unpack(u32 power_state, + struct psci_power_state *state) +{ + state->id = (power_state & PSCI_0_2_POWER_STATE_ID_MASK) >> + PSCI_0_2_POWER_STATE_ID_SHIFT; + state->type = (power_state & PSCI_0_2_POWER_STATE_TYPE_MASK) >> + PSCI_0_2_POWER_STATE_TYPE_SHIFT; + state->affinity_level = + (power_state & PSCI_0_2_POWER_STATE_AFFL_MASK) >> + PSCI_0_2_POWER_STATE_AFFL_SHIFT; +} + /* * The following two functions are invoked via the invoke_psci_fn pointer * and will not be inlined, allowing us to piggyback on the AAPCS. @@ -199,6 +215,63 @@ static int psci_migrate_info_type(void) return err; } +static int __maybe_unused cpu_psci_cpu_init_idle(struct device_node *cpu_node, + unsigned int cpu) +{ + int i, ret, count = 0; + struct psci_power_state *psci_states; + struct device_node *state_node; + + /* + * If the PSCI cpu_suspend function hook has not been initialized + * idle states must not be enabled, so bail out + */ + if (!psci_ops.cpu_suspend) + return -EOPNOTSUPP; + + /* Count idle states */ + while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states", + count))) { + count++; + of_node_put(state_node); + } + + if (!count) + return -ENODEV; + + psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL); + if (!psci_states) + return -ENOMEM; + + for (i = 0; i < count; i++) { + u32 psci_power_state; + + state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i); + + ret = of_property_read_u32(state_node, + "arm,psci-suspend-param", + &psci_power_state); + if (ret) { + pr_warn(" * %s missing arm,psci-suspend-param property\n", + state_node->full_name); + of_node_put(state_node); + goto free_mem; + } + + of_node_put(state_node); + pr_debug("psci-power-state %#x index %d\n", psci_power_state, + i); + psci_power_state_unpack(psci_power_state, &psci_states[i]); + } + /* Idle states parsed correctly, initialize per-cpu pointer */ + per_cpu(psci_power_state, cpu) = psci_states; + return 0; + +free_mem: + kfree(psci_states); + return ret; +} + static int get_set_conduit_method(struct device_node *np) { const char *method; @@ -436,8 +509,39 @@ static int cpu_psci_cpu_kill(unsigned int cpu) #endif #endif +static int psci_suspend_finisher(unsigned long index) +{ + struct psci_power_state *state = __get_cpu_var(psci_power_state); + + return psci_ops.cpu_suspend(state[index - 1], + virt_to_phys(cpu_resume)); +} + +static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index) +{ + int ret; + struct psci_power_state *state = __get_cpu_var(psci_power_state); + /* + * idle state index 0 corresponds to wfi, should never be called + * from the cpu_suspend operations + */ + if (WARN_ON_ONCE(!index)) + return -EINVAL; + + if (state->type == PSCI_POWER_STATE_TYPE_STANDBY) + ret = psci_ops.cpu_suspend(state[index - 1], 0); + else + ret = __cpu_suspend(index, psci_suspend_finisher); + + return ret; +} + const struct cpu_operations cpu_psci_ops = { .name = "psci", +#ifdef CONFIG_CPU_IDLE + .cpu_init_idle = cpu_psci_cpu_init_idle, + .cpu_suspend = cpu_psci_cpu_suspend, +#endif #ifdef CONFIG_SMP .cpu_init = cpu_psci_cpu_init, .cpu_prepare = cpu_psci_cpu_prepare, -- 1.9.1