[Xen-devel] [PATCH V1 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>

The "interrupts-extended" property is a special form for use when
a node needs to reference multiple interrupt parents.

According to the:
Linux/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt

But, there are cases when "interrupts-extended" property is used for
"outside /soc node" with a single interrupt parent as an equivalent of
pairs ("interrupt-parent" + "interrupts").

The good example here is ARCH timer node for R-Car Gen3/Gen2 family,
which is mandatory device for Xen usage on ARM. And without ability
to handle such nodes, Xen fails to operate.

So, this patch adds required support for Xen to be able to handle
nodes with that property.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>

---
    Changes RFC -> V1:
        - Explain in the commit message regarding property usage, add a link
          to the bindings.
        - Don't try to look for "interrupts" property if "interrupts-extended"
          property is present, but doesn't contain any interrupts
          (dt_count_phandle_with_args returns 0).
        - Add messages to tell which property is used.
---
 xen/common/device_tree.c | 36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 65862b5..e107c6f 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -987,15 +987,27 @@ unsigned int dt_number_of_irq(const struct dt_device_node 
*device)
     const struct dt_device_node *p;
     const __be32 *intspec, *tmp;
     u32 intsize, intlen;
+    int intnum;
 
     dt_dprintk("dt_irq_number: dev=%s\n", device->full_name);
 
+    /* Try the new-style interrupts-extended first */
+    intnum = dt_count_phandle_with_args(device, "interrupts-extended",
+                                        "#interrupt-cells");
+    if ( intnum >= 0 )
+    {
+        dt_dprintk(" using 'interrupts-extended' property\n");
+        dt_dprintk(" intnum=%d\n", intnum);
+        return intnum;
+    }
+
     /* Get the interrupts property */
     intspec = dt_get_property(device, "interrupts", &intlen);
     if ( intspec == NULL )
         return 0;
     intlen /= sizeof(*intspec);
 
+    dt_dprintk(" using 'interrupts' property\n");
     dt_dprintk(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);
 
     /* Look for the interrupt parent. */
@@ -1420,21 +1432,39 @@ int dt_device_get_raw_irq(const struct dt_device_node 
*device,
     const __be32 *intspec, *tmp, *addr;
     u32 intsize, intlen;
     int res = -EINVAL;
+    struct dt_phandle_args args;
+    int i;
 
     dt_dprintk("dt_device_get_raw_irq: dev=%s, index=%u\n",
                device->full_name, index);
 
+    /* Get the reg property (if any) */
+    addr = dt_get_property(device, "reg", NULL);
+
+    /* Try the new-style interrupts-extended first */
+    res = dt_parse_phandle_with_args(device, "interrupts-extended",
+                                     "#interrupt-cells", index, &args);
+    if ( !res )
+    {
+        dt_dprintk(" using 'interrupts-extended' property\n");
+        dt_dprintk(" intspec=%d intsize=%d\n", args.args[0], args.args_count);
+
+        for ( i = 0; i < args.args_count; i++ )
+            args.args[i] = cpu_to_be32(args.args[i]);
+
+        return dt_irq_map_raw(args.np, args.args, args.args_count,
+                              addr, out_irq);
+    }
+
     /* Get the interrupts property */
     intspec = dt_get_property(device, "interrupts", &intlen);
     if ( intspec == NULL )
         return -EINVAL;
     intlen /= sizeof(*intspec);
 
+    dt_dprintk(" using 'interrupts' property\n");
     dt_dprintk(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);
 
-    /* Get the reg property (if any) */
-    addr = dt_get_property(device, "reg", NULL);
-
     /* Look for the interrupt parent. */
     p = dt_irq_find_parent(device);
     if ( p == NULL )
-- 
2.7.4


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