[Minios-devel] [UNIKRAFT PATCHv2 6/7] plat/common: Find and register IRQ for arch_timer

[Jia He <justin.he@xxxxxxx>]

Currently, in unikraft, the timer interrupt hasn't been
used to update ticks periodically. We just mask it in
IRQ handler, and wait for sleep function to set new
match counter and unmask IRQ.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
Signed-off-by: Jianyong Wu <jianyong.wu@xxxxxxx>
Signed-off-by: Jia He <justin.he@xxxxxxx>
---
 plat/common/arm/time.c | 70 +++++++++++++++++++++++++++++++++++-------
 1 file changed, 59 insertions(+), 11 deletions(-)

diff --git a/plat/common/arm/time.c b/plat/common/arm/time.c
index 75b8183..9365ceb 100644
--- a/plat/common/arm/time.c
+++ b/plat/common/arm/time.c
@@ -36,10 +36,17 @@
 #include <ofw/fdt.h>
 #include <uk/assert.h>
 #include <uk/plat/time.h>
+#include <uk/plat/lcpu.h>
 #include <uk/plat/irq.h>
 #include <uk/bitops.h>
 #include <cpu.h>
 #include <kvm/sections.h>
+#include <gic_fdt.h>
+
+/* Bits definition of cntv_ctl_el0 register */
+#define GT_TIMER_ENABLE                0x01
+#define GT_TIMER_MASK_IRQ      0x02
+#define GT_TIMER_IRQ_STATUS    0x04
 
 static const char * const arch_timer_list[] = {
        "arm,armv8-timer",
@@ -127,6 +134,28 @@ static void calculate_mult_shift(uint32_t *pmult, uint8_t 
*pshift,
        *pshift = shift;
 }
 
+static inline void generic_timer_enable(void)
+{
+       SYSREG_WRITE32(cntv_ctl_el0, GT_TIMER_ENABLE);
+}
+
+static inline void generic_timer_mask_irq(void)
+{
+       SYSREG_WRITE32(cntv_ctl_el0,
+               SYSREG_READ32(cntv_ctl_el0) | GT_TIMER_MASK_IRQ);
+}
+
+static inline void generic_timer_unmask_irq(void)
+{
+       SYSREG_WRITE32(cntv_ctl_el0,
+               SYSREG_READ32(cntv_ctl_el0) & (~GT_TIMER_MASK_IRQ));
+}
+
+static inline void generic_timer_update_compare(uint64_t new_val)
+{
+       SYSREG_WRITE64(cntv_cval_el0, new_val);
+}
+
 static uint32_t generic_timer_get_frequency(int fdt_timer)
 {
        int len;
@@ -221,6 +250,18 @@ static int generic_timer_init(int fdt_timer)
        return 0;
 }
 
+static int generic_timer_irq_handler(void *arg __unused)
+{
+       /*
+        * We just mask the IRQ here, the scheduler will call
+        * generic_timer_cpu_block, and then unmask the IRQ.
+        */
+       generic_timer_mask_irq();
+
+       /* Yes, we handled the irq. */
+       return 1;
+}
+
 unsigned long sched_have_pending_events;
 
 void time_block_until(__snsec until)
@@ -248,16 +289,10 @@ __nsec ukplat_wall_clock(void)
        return generic_timer_monotonic() + generic_timer_epochoffset();
 }
 
-static int timer_handler(void *arg __unused)
-{
-       /* Yes, we handled the irq. */
-       return 1;
-}
-
 /* must be called before interrupts are enabled */
 void ukplat_time_init(void)
 {
-       int rc, fdt_timer;
+       int rc, irq, fdt_timer;
 
        /*
         * Monotonic time begins at boot_ticks (first read of counter
@@ -271,11 +306,24 @@ void ukplat_time_init(void)
        if (fdt_timer < 0)
                UK_CRASH("Could not find arch timer!\n");
 
-       rc = ukplat_irq_register(0, timer_handler, NULL);
-       if (rc < 0)
-               UK_CRASH("Failed to register timer interrupt handler\n");
-
        rc = generic_timer_init(fdt_timer);
        if (rc < 0)
                UK_CRASH("Failed to initialize platform time\n");
+
+       irq = gic_get_irq_from_dtb(_libkvmplat_dtb, fdt_timer, 2);
+       if (irq < 0)
+               UK_CRASH("Failed to find IRQ number from DTB\n");
+
+       rc = ukplat_irq_register(irq, generic_timer_irq_handler, NULL);
+       if (rc < 0)
+               UK_CRASH("Failed to register timer interrupt handler\n");
+
+       /*
+        * Mask IRQ before scheduler start working. Otherwise we will get
+        * unexpected timer interrupts when system is booting.
+        */
+       generic_timer_mask_irq();
+
+       /* Enable timer */
+       generic_timer_enable();
 }
-- 
2.17.1


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