[Xen-devel] [PATCH RFC 16/35] ARM64 / ACPI: Parse GTDT to initialize timer

[parth.dixit@xxxxxxxxxx]

From: Naresh Bhat <naresh.bhat@xxxxxxxxxx>

Parse GTDT (Generic Timer Descriptor Table) to initialize timer.
Using the information presented by GTDT to initialize the arch
timer (not momery-mapped).

Signed-off-by: Naresh Bhat <naresh.bhat@xxxxxxxxxx>
Signed-off-by: Parth Dixit <parth.dixit@xxxxxxxxxx>
---
 xen/arch/arm/setup.c   |  6 +++++
 xen/arch/arm/time.c    | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++
 xen/include/xen/time.h |  1 +
 3 files changed, 73 insertions(+)

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 569b2da..af9f429 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -775,7 +775,12 @@ void __init start_xen(unsigned long boot_phys_offset,
     smp_init_cpus();
     cpus = smp_get_max_cpus();
 
+/* Comment for now take it after GIC initialization */
+#if defined(CONFIG_ACPI) && defined(CONFIG_ARM_64)
+   init_xen_acpi_time();
+#else
     init_xen_time();
+#endif
 
     gic_init();
 
@@ -789,6 +794,7 @@ void __init start_xen(unsigned long boot_phys_offset,
     xsm_dt_init();
 
     init_maintenance_interrupt();
+
     init_timer_interrupt();
 
     timer_init();
diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index 0add494..0d4c26d 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -29,6 +29,7 @@
 #include <xen/time.h>
 #include <xen/sched.h>
 #include <xen/event.h>
+#include <xen/acpi.h>
 #include <asm/system.h>
 #include <asm/time.h>
 #include <asm/gic.h>
@@ -239,6 +240,71 @@ struct tm wallclock_time(uint64_t *ns)
     return (struct tm) { 0 };
 }
 
+#if defined(CONFIG_ARM_64) && defined(CONFIG_ACPI)
+
+#define ACPI_GTDT_INTR_MASK 0x3
+
+static int GTDT_INTRL_TAB[] ={ DT_IRQ_TYPE_LEVEL_HIGH, DT_IRQ_TYPE_EDGE_RISING,
+                          DT_IRQ_TYPE_LEVEL_LOW ,DT_IRQ_TYPE_EDGE_FALLING};
+
+/* Initialize per-processor generic timer */
+static int __init arch_timer_acpi_init(struct acpi_table_header *table)
+{
+    int res;
+    int type;
+    struct acpi_table_gtdt *gtdt;
+
+    gtdt = (struct acpi_table_gtdt *)table;
+
+    /* Initialize all the generic timer IRQ variable from GTDT table */
+
+    type = GTDT_INTRL_TAB[gtdt->non_secure_el1_flags & ACPI_GTDT_INTR_MASK];
+    acpi_set_irq(gtdt->non_secure_el1_interrupt, type);
+    timer_irq[TIMER_PHYS_NONSECURE_PPI] = gtdt->non_secure_el1_interrupt;
+
+    type = GTDT_INTRL_TAB[gtdt->secure_el1_flags & ACPI_GTDT_INTR_MASK];
+    acpi_set_irq(gtdt->secure_el1_interrupt, type);
+    timer_irq[TIMER_PHYS_SECURE_PPI] = gtdt->secure_el1_interrupt;
+
+    type = GTDT_INTRL_TAB[gtdt->non_secure_el2_flags & ACPI_GTDT_INTR_MASK];
+    acpi_set_irq(gtdt->non_secure_el2_interrupt, type);
+    timer_irq[TIMER_HYP_PPI] = gtdt->non_secure_el2_interrupt;
+
+    type = GTDT_INTRL_TAB[gtdt->virtual_timer_flags & ACPI_GTDT_INTR_MASK];
+    acpi_set_irq(gtdt->virtual_timer_interrupt, type);
+    timer_irq[TIMER_VIRT_PPI] = gtdt->virtual_timer_interrupt;
+
+    printk("Generic Timer IRQ from ACPI GTDT: phys=%u hyp=%u virt=%u\n",
+           timer_irq[TIMER_PHYS_NONSECURE_PPI],
+           timer_irq[TIMER_HYP_PPI],
+           timer_irq[TIMER_VIRT_PPI]);
+
+    res = platform_init_time();
+    if ( res )
+        printk("Timer: Cannot initialize platform timer");
+
+    /* Check that this CPU supports the Generic Timer interface */
+    if ( !cpu_has_gentimer )
+        printk("CPU does not support the Generic Timer v1 interface");
+
+    cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;
+
+    boot_count = READ_SYSREG64(CNTPCT_EL0);
+
+    printk("Using generic timer at %lu KHz\n", cpu_khz);
+
+    return 0;
+}
+
+int __init init_xen_acpi_time(void)
+{
+   /* Initialize all the generic timers presented in GTDT */
+   acpi_table_parse(ACPI_SIG_GTDT, arch_timer_acpi_init);
+   return 0;
+}
+
+#endif
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/xen/time.h b/xen/include/xen/time.h
index 709501f..4598a0c 100644
--- a/xen/include/xen/time.h
+++ b/xen/include/xen/time.h
@@ -11,6 +11,7 @@
 #include <xen/types.h>
 #include <public/xen.h>
 
+extern int init_xen_acpi_time(void);
 extern int init_xen_time(void);
 extern void cstate_restore_tsc(void);
 
-- 
1.9.1


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