Using the information presented by GTDT (Generic Timer Description Table) to initialize the arch timer (not memory-mapped).
CC: Daniel Lezcano daniel.lezcano@linaro.org CC: Thomas Gleixner tglx@linutronix.de Originally-by: Amit Daniel Kachhap amit.daniel@samsung.com Tested-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com Tested-by: Yijing Wang wangyijing@huawei.com Tested-by: Mark Langsdorf mlangsdo@redhat.com Tested-by: Jon Masters jcm@redhat.com Tested-by: Timur Tabi timur@codeaurora.org Tested-by: Robert Richter rrichter@cavium.com Acked-by: Robert Richter rrichter@cavium.com Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- arch/arm64/kernel/time.c | 7 ++ drivers/clocksource/arm_arch_timer.c | 132 ++++++++++++++++++++++++++++------- include/linux/clocksource.h | 6 ++ 3 files changed, 118 insertions(+), 27 deletions(-)
diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c index 1a7125c..42f9195 100644 --- a/arch/arm64/kernel/time.c +++ b/arch/arm64/kernel/time.c @@ -35,6 +35,7 @@ #include <linux/delay.h> #include <linux/clocksource.h> #include <linux/clk-provider.h> +#include <linux/acpi.h>
#include <clocksource/arm_arch_timer.h>
@@ -72,6 +73,12 @@ void __init time_init(void)
tick_setup_hrtimer_broadcast();
+ /* + * Since ACPI or FDT will only one be available in the system, + * we can use acpi_generic_timer_init() here safely + */ + acpi_generic_timer_init(); + arch_timer_rate = arch_timer_get_rate(); if (!arch_timer_rate) panic("Unable to initialise architected timer.\n"); diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 095c177..407aa63 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -21,6 +21,7 @@ #include <linux/io.h> #include <linux/slab.h> #include <linux/sched_clock.h> +#include <linux/acpi.h>
#include <asm/arch_timer.h> #include <asm/virt.h> @@ -370,8 +371,12 @@ arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np) if (arch_timer_rate) return;
- /* Try to determine the frequency from the device tree or CNTFRQ */ - if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) { + /* + * Try to determine the frequency from the device tree or CNTFRQ, + * if ACPI is enabled, get the frequency from CNTFRQ ONLY. + */ + if (!acpi_disabled || + of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) { if (cntbase) arch_timer_rate = readl_relaxed(cntbase + CNTFRQ); else @@ -690,28 +695,8 @@ static void __init arch_timer_common_init(void) arch_timer_arch_init(); }
-static void __init arch_timer_init(struct device_node *np) +static void __init arch_timer_init(void) { - int i; - - if (arch_timers_present & ARCH_CP15_TIMER) { - pr_warn("arch_timer: multiple nodes in dt, skipping\n"); - return; - } - - arch_timers_present |= ARCH_CP15_TIMER; - for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++) - arch_timer_ppi[i] = irq_of_parse_and_map(np, i); - arch_timer_detect_rate(NULL, np); - - /* - * If we cannot rely on firmware initializing the timer registers then - * we should use the physical timers instead. - */ - if (IS_ENABLED(CONFIG_ARM) && - of_property_read_bool(np, "arm,cpu-registers-not-fw-configured")) - arch_timer_use_virtual = false; - /* * If HYP mode is available, we know that the physical timer * has been configured to be accessible from PL1. Use it, so @@ -730,13 +715,39 @@ static void __init arch_timer_init(struct device_node *np) } }
- arch_timer_c3stop = !of_property_read_bool(np, "always-on"); - arch_timer_register(); arch_timer_common_init(); } -CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_init); -CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_init); + +static void __init arch_timer_of_init(struct device_node *np) +{ + int i; + + if (arch_timers_present & ARCH_CP15_TIMER) { + pr_warn("arch_timer: multiple nodes in dt, skipping\n"); + return; + } + + arch_timers_present |= ARCH_CP15_TIMER; + for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++) + arch_timer_ppi[i] = irq_of_parse_and_map(np, i); + + arch_timer_detect_rate(NULL, np); + + arch_timer_c3stop = !of_property_read_bool(np, "always-on"); + + /* + * If we cannot rely on firmware initializing the timer registers then + * we should use the physical timers instead. + */ + if (IS_ENABLED(CONFIG_ARM) && + of_property_read_bool(np, "arm,cpu-registers-not-fw-configured")) + arch_timer_use_virtual = false; + + arch_timer_init(); +} +CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init); +CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);
static void __init arch_timer_mem_init(struct device_node *np) { @@ -803,3 +814,70 @@ static void __init arch_timer_mem_init(struct device_node *np) } CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem", arch_timer_mem_init); + +#ifdef CONFIG_ACPI +static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags) +{ + int trigger, polarity; + + if (!interrupt) + return 0; + + trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE + : ACPI_LEVEL_SENSITIVE; + + polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW + : ACPI_ACTIVE_HIGH; + + return acpi_register_gsi(NULL, interrupt, trigger, polarity); +} + +/* Initialize per-processor generic timer */ +static int __init arch_timer_acpi_init(struct acpi_table_header *table) +{ + struct acpi_table_gtdt *gtdt; + + if (arch_timers_present & ARCH_CP15_TIMER) { + pr_warn("arch_timer: already initialized, skipping\n"); + return -EINVAL; + } + + gtdt = container_of(table, struct acpi_table_gtdt, header); + + arch_timers_present |= ARCH_CP15_TIMER; + + arch_timer_ppi[PHYS_SECURE_PPI] = + map_generic_timer_interrupt(gtdt->secure_el1_interrupt, + gtdt->secure_el1_flags); + + arch_timer_ppi[PHYS_NONSECURE_PPI] = + map_generic_timer_interrupt(gtdt->non_secure_el1_interrupt, + gtdt->non_secure_el1_flags); + + arch_timer_ppi[VIRT_PPI] = + map_generic_timer_interrupt(gtdt->virtual_timer_interrupt, + gtdt->virtual_timer_flags); + + arch_timer_ppi[HYP_PPI] = + map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt, + gtdt->non_secure_el2_flags); + + /* Get the frequency from CNTFRQ */ + arch_timer_detect_rate(NULL, NULL); + + /* Always-on capability */ + arch_timer_c3stop = !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON); + + arch_timer_init(); + return 0; +} + +/* Initialize all the generic timers presented in GTDT */ +void __init acpi_generic_timer_init(void) +{ + if (acpi_disabled) + return; + + acpi_table_parse(ACPI_SIG_GTDT, arch_timer_acpi_init); +} +#endif diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index abcafaa..af6155a 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -346,4 +346,10 @@ extern void clocksource_of_init(void); static inline void clocksource_of_init(void) {} #endif
+#ifdef CONFIG_ACPI +void acpi_generic_timer_init(void); +#else +static inline void acpi_generic_timer_init(void) { } +#endif + #endif /* _LINUX_CLOCKSOURCE_H */