[PATCH v3 2/2] arch/arm: time: Add support for parsing interrupts by names

["Andrei Cherechesu (OSS)" <andrei.cherechesu@xxxxxxxxxxx>]

From: Andrei Cherechesu <andrei.cherechesu@xxxxxxx>

Added support for parsing the ARM generic timer interrupts DT
node by the "interrupt-names" property, if it is available.

If not available, the usual parsing based on the expected
IRQ order is performed.

Also treated returning 0 as an error case for the
platform_get_irq() calls, since it is not a valid PPI ID and
treating it as a valid case would only cause Xen to BUG() later,
when trying to reserve vIRQ being SGI.

Added the "hyp-virt" PPI to the timer PPI list, even
though it's currently not in use. If the "hyp-virt" PPI is
not found, the hypervisor won't panic.

Signed-off-by: Andrei Cherechesu <andrei.cherechesu@xxxxxxx>
---
 xen/arch/arm/include/asm/time.h |  3 ++-
 xen/arch/arm/time.c             | 26 ++++++++++++++++++++++----
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/include/asm/time.h b/xen/arch/arm/include/asm/time.h
index 4b401c1110..49ad8c1a6d 100644
--- a/xen/arch/arm/include/asm/time.h
+++ b/xen/arch/arm/include/asm/time.h
@@ -82,7 +82,8 @@ enum timer_ppi
     TIMER_PHYS_NONSECURE_PPI = 1,
     TIMER_VIRT_PPI = 2,
     TIMER_HYP_PPI = 3,
-    MAX_TIMER_PPI = 4,
+    TIMER_HYP_VIRT_PPI = 4,
+    MAX_TIMER_PPI = 5,
 };
 
 /*
diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index 433d7be909..0b482d7db3 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -149,15 +149,33 @@ static void __init init_dt_xen_time(void)
 {
     int res;
     unsigned int i;
+    bool has_names;
+    static const char * const timer_irq_names[MAX_TIMER_PPI] __initconst = {
+        [TIMER_PHYS_SECURE_PPI] = "sec-phys",
+        [TIMER_PHYS_NONSECURE_PPI] = "phys",
+        [TIMER_VIRT_PPI] = "virt",
+        [TIMER_HYP_PPI] = "hyp-phys",
+        [TIMER_HYP_VIRT_PPI] = "hyp-virt",
+    };
+
+    has_names = dt_property_read_bool(timer, "interrupt-names");
 
     /* Retrieve all IRQs for the timer */
     for ( i = TIMER_PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++ )
     {
-        res = platform_get_irq(timer, i);
-
-        if ( res < 0 )
+        if ( has_names )
+            res = platform_get_irq_byname(timer, timer_irq_names[i]);
+        else
+            res = platform_get_irq(timer, i);
+
+        if ( res > 0 )
+            timer_irq[i] = res;
+        /*
+         * Do not panic if "hyp-virt" PPI is not found, since it's not
+         * currently used.
+         */
+        else if ( i != TIMER_HYP_VIRT_PPI )
             panic("Timer: Unable to retrieve IRQ %u from the device tree\n", 
i);
-        timer_irq[i] = res;
     }
 }
 
-- 
2.35.1