[Xen-devel] [RFC 12/29] xen/arm: Introduce gic_irq_xlate

[Julien Grall <julien.grall@xxxxxxxxxx>]

This function translates an interrupt specifier to an IRQ number and IRQ
type (ie: level trigger, edge trigger,...). It's GIC specific.

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
 xen/arch/arm/gic.c        |   20 ++++++++++++++++++++
 xen/arch/arm/setup.c      |    1 +
 xen/include/asm-arm/gic.h |    4 ++++
 3 files changed, 25 insertions(+)

diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index e03bb67..1f44fea 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -329,6 +329,26 @@ static void __cpuinit gic_hyp_disable(void)
     GICH[GICH_HCR] = 0;
 }
 
+int gic_irq_xlate(const u32 *intspec, unsigned int intsize,
+                  unsigned int *out_hwirq,
+                  unsigned int *out_type)
+{
+    if ( intsize < 3 )
+        return -EINVAL;
+
+    /* Get the interrupt number and add 16 to skip over SGIs */
+    *out_hwirq = intspec[1] + 16;
+
+    /* For SPIs, we need to add 16 more to get the GIC irq ID number */
+    if ( !intspec[0] )
+        *out_hwirq += 16;
+
+    if ( out_type )
+        *out_type = intspec[2] & IRQ_TYPE_SENSE_MASK;
+
+    return 0;
+}
+
 /* Set up the GIC */
 void __init gic_init(void)
 {
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 77d0879..51f4bba 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -429,6 +429,7 @@ void __init start_xen(unsigned long boot_phys_offset,
     setup_mm(fdt_paddr, fdt_size);
 
     dt_unflatten_host_device_tree();
+    dt_irq_xlate = gic_irq_xlate;
 
 #ifdef EARLY_UART_ADDRESS
     /* TODO Need to get device tree or command line for UART address */
diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h
index 2fac673..945e8db 100644
--- a/xen/include/asm-arm/gic.h
+++ b/xen/include/asm-arm/gic.h
@@ -187,6 +187,10 @@ extern void send_SGI_allbutself(enum gic_sgi sgi);
 /* print useful debug info */
 extern void gic_dump_info(struct vcpu *v);
 
+/* IRQ translation function for the device tree */
+int gic_irq_xlate(const u32 *intspec, unsigned int intsize,
+                  unsigned int *out_hwirq, unsigned int *out_type);
+
 #endif /* __ASSEMBLY__ */
 #endif
 
-- 
Julien Grall


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