Re: [Linaro-acpi] [PATCH v9 17/21] clocksource / arch_timer: Parse GTDT to initialize arch timer

On Wed, 25 Feb 2015 16:39:57 +0800 , Hanjun Guo hanjun.guo@linaro.org wrote:

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

Reviewed-by: Grant Likely grant.likely@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 a3025e7..ea62fc7 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -22,6 +22,7 @@ #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> @@ -371,8 +372,12 @@ 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

@@ -691,28 +696,8 @@ 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

@@ -731,13 +716,39 @@ 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) { @@ -804,3 +815,70 @@ 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 9c78d15..2b2e1f8 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -244,4 +244,10 @@ 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 */

1.9.1