[RFC part3 PATCH 1/2] clocksource / arch_timer: Use ACPI GTDT table to initialize arch timer

Hanjun Guo
2013-12-03T16:42:41Z

ACPI GTDT (Generic Timer Description Table) contains information for
arch timer initialization, this patch use this table to probe arm timer.

GTDT table is used for ARM/ARM64 only, please refer to chapter 5.2.24
of ACPI 5.0 spec for detailed inforamtion

Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
---
drivers/clocksource/arm_arch_timer.c | 129 ++++++++++++++++++++++++++++++----
include/clocksource/arm_arch_timer.h | 7 +-
2 files changed, 120 insertions(+), 16 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 95fb944..c968041 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>
@@ -632,20 +633,8 @@ 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 HYP mode is available, we know that the physical timer
* has been configured to be accessible from PL1. Use it, so
@@ -667,8 +656,118 @@ static void __init arch_timer_init(struct device_node *np)
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_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);
+
+#ifdef CONFIG_ACPI
+void __init arch_timer_acpi_init(void)
+{
+ struct acpi_table_gtdt *gtdt;
+ acpi_size tbl_size;
+ int trigger, polarity;
+ void __iomem *base = NULL;
+
+ if (acpi_disabled)
+ return;
+
+ if (arch_timers_present & ARCH_CP15_TIMER) {
+ pr_warn("arch_timer: already initialized, skipping\n");
+ return;
+ }
+
+ if (ACPI_FAILURE(acpi_get_table_with_size(ACPI_SIG_GTDT, 0,
+ (struct acpi_table_header **)&gtdt, &tbl_size))) {
+ pr_err("arch_timer: GTDT table not defined\n");
+ return;
+ }
+
+ arch_timers_present |= ARCH_CP15_TIMER;
+
+ /*
+ * Get the timer frequency. Since there is no frequency info
+ * in the GTDT table, so we should read it from CNTFREG register
+ * or hard code here to wait for the new ACPI spec available.
+ */
+ if (!gtdt->address) {
+ arch_timer_rate = arch_timer_get_cntfrq();
+ } else {
+ base = ioremap(gtdt->address, CNTFRQ);
+ if (!base) {
+ pr_warn("arch_timer: unable to map arch timer base address\n");
+ return;
+ }
+
+ arch_timer_rate = readl_relaxed(base + CNTFRQ);
+ iounmap(base);
+ }
+
+ if (!arch_timer_rate) {
+ /* Hard code here to set frequence ? */
+ pr_warn("arch_timer: Could not get frequency from GTDT table or CNTFREG\n");
+ }
+
+ if (gtdt->secure_pl1_interrupt) {
+ trigger = (gtdt->secure_pl1_flags & ACPI_GTDT_INTERRUPT_MODE) ?
+ ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
+ polarity =
+ (gtdt->secure_pl1_flags & ACPI_GTDT_INTERRUPT_POLARITY)
+ ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
+ arch_timer_ppi[0] = acpi_register_gsi(NULL,
+ gtdt->secure_pl1_interrupt, trigger, polarity);
+ }
+ if (gtdt->non_secure_pl1_interrupt) {
+ trigger =
+ (gtdt->non_secure_pl1_flags & ACPI_GTDT_INTERRUPT_MODE)
+ ? ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
+ polarity =
+ (gtdt->non_secure_pl1_flags & ACPI_GTDT_INTERRUPT_POLARITY)
+ ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
+ arch_timer_ppi[1] = acpi_register_gsi(NULL,
+ gtdt->non_secure_pl1_interrupt, trigger, polarity);
+ }
+ if (gtdt->virtual_timer_interrupt) {
+ trigger = (gtdt->virtual_timer_flags & ACPI_GTDT_INTERRUPT_MODE)
+ ? ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
+ polarity =
+ (gtdt->virtual_timer_flags & ACPI_GTDT_INTERRUPT_POLARITY)
+ ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
+ arch_timer_ppi[2] = acpi_register_gsi(NULL,
+ gtdt->virtual_timer_interrupt, trigger, polarity);
+ }
+ if (gtdt->non_secure_pl2_interrupt) {
+ trigger =
+ (gtdt->non_secure_pl2_flags & ACPI_GTDT_INTERRUPT_MODE)
+ ? ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
+ polarity =
+ (gtdt->non_secure_pl2_flags & ACPI_GTDT_INTERRUPT_POLARITY)
+ ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
+ arch_timer_ppi[3] = acpi_register_gsi(NULL,
+ gtdt->non_secure_pl2_interrupt, trigger, polarity);
+ }
+
+ early_acpi_os_unmap_memory(gtdt, tbl_size);
+ arch_timer_init();
+}
+#else
+void __init arch_timer_acpi_init(void) { return; };
+#endif

static void __init arch_timer_mem_init(struct device_node *np)
{
diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h
index 6d26b40..2654edf 100644
--- a/include/clocksource/arm_arch_timer.h
+++ b/include/clocksource/arm_arch_timer.h
@@ -48,7 +48,7 @@ enum arch_timer_reg {
extern u32 arch_timer_get_rate(void);
extern u64 (*arch_timer_read_counter)(void);
extern struct timecounter *arch_timer_get_timecounter(void);
-
+extern void __init arch_timer_acpi_init(void);
#else

static inline u32 arch_timer_get_rate(void)
@@ -66,6 +66,11 @@ static inline struct timecounter *arch_timer_get_timecounter(void)
return NULL;
}

+static inline void arch_timer_acpi_init(void)
+{
+ return;
+}
+
#endif

#endif
--
1.7.9.5