[PATCH v3 1/7] ARM: davinci, intc: Add OF support for TI interrupt controller

[hs@denx.de (Heiko Schocher)]

Add a function to initialize the Common Platform Interrupt Controller
(cp_intc) from TI used on OMAP-L1x SoCs using a device tree node.

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: davinci-linux-open-source at linux.davincidsp.com
Cc: linux-arm-kernel at lists.infradead.org
Cc: devicetree-discuss at lists.ozlabs.org
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Sergei Shtylyov <sshtylyov@mvista.com>

---
- changes for v2:
- add comment from Grant Likely:
  - migrate the whole interrupt controller to natively use an
    irq_domain. Rebased complete patchserie to:
    git://git.secretlab.ca/git/linux-2.6.git irqdomain/next

    commit 3a806bfcde2cc3e4853f2807b2e3c94e7ccaf450
    Author: Grant Likely <grant.likely@secretlab.ca>
    Date:   Fri Jan 27 06:44:34 2012 -0700

    irq_domain: mostly eliminate slow-path revmap lookups
- changes for v3:
  - add comments from Sergei Shtylyov:
    - rename compatible" prop to "ti,cp_intc"
    - cp_intc_init() is now also for the of case
      the name of the init function (it calls the
      "new" __cp_intc_init() function, which was
      the "old" cp_intc_init()). Through this
      rework the changes for OF is better visible.
      As the OF case uses the irq_domain rework from
      Grant Likely, maybe the none OF case can use
      this also, but this should be tested on a hw ...
  - rebased to:
    git://git.secretlab.ca/git/linux-2.6.git irqdomain/next

    commit 280ad7fda5f95211857fda38960f2b6fdf6edd3e
    Author: Grant Likely <grant.likely@secretlab.ca>
    Date:   Fri Feb 24 14:58:54 2012 -0700

    mfd: twl-core: Add IRQ_DOMAIN dependency

 .../devicetree/bindings/arm/davinci/intc.txt       |   27 ++++++
 arch/arm/mach-davinci/cp_intc.c                    |   87 +++++++++++++++++--
 2 files changed, 104 insertions(+), 10 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/arm/davinci/intc.txt

diff --git a/Documentation/devicetree/bindings/arm/davinci/intc.txt b/Documentation/devicetree/bindings/arm/davinci/intc.txt
new file mode 100644
index 0000000..dfd6a560
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/davinci/intc.txt
@@ -0,0 +1,27 @@
+* TI Common Platform Interrupt Controller
+
+Common Platform Interrupt Controller (cp_intc) is used on
+OMAP-L1x SoCs and can support several configurable number
+of interrupts.
+
+Main node required properties:
+
+- compatible : should be:
+	"ti,cp_intc"
+- interrupt-controller : Identifies the node as an interrupt controller
+- #interrupt-cells : Specifies the number of cells needed to encode an
+  interrupt source. The type shall be a <u32> and the value shall be 1.
+
+  The cell contains the interrupt number in the range [0-128].
+- ti,intc-size: Number of interrupts handled by the interrupt controller.
+- reg: physical base address and size of the intc registers map.
+
+Example:
+
+	intc: interrupt-controller at 1 {
+		compatible = "ti,cp_intc";
+		interrupt-controller;
+		#interrupt-cells = <1>;
+		ti,intc-size = <101>;
+		reg = <0xfffee000 0x2000>;
+	};
diff --git a/arch/arm/mach-davinci/cp_intc.c b/arch/arm/mach-davinci/cp_intc.c
index f83152d..585114a 100644
--- a/arch/arm/mach-davinci/cp_intc.c
+++ b/arch/arm/mach-davinci/cp_intc.c
@@ -9,9 +9,14 @@
  * kind, whether express or implied.
  */
 
+#include <linux/export.h>
 #include <linux/init.h>
 #include <linux/irq.h>
+#include <linux/irqdomain.h>
 #include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
 
 #include <mach/common.h>
 #include <mach/cp_intc.h>
@@ -99,18 +104,45 @@ static struct irq_chip cp_intc_irq_chip = {
 	.irq_set_wake	= cp_intc_set_wake,
 };
 
-void __init cp_intc_init(void)
+static struct irq_domain *cp_intc_domain;
+
+static int cp_intc_host_map(struct irq_domain *h, unsigned int virq,
+			  irq_hw_number_t hw)
 {
-	unsigned long num_irq	= davinci_soc_info.intc_irq_num;
+	pr_debug("cp_intc_host_map(%d, 0x%lx)\n", virq, hw);
+
+	irq_set_chip(virq, &cp_intc_irq_chip);
+	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
+	irq_set_handler(virq, handle_edge_irq);
+	return 0;
+}
+
+static const struct irq_domain_ops cp_intc_host_ops = {
+	.map = cp_intc_host_map,
+	.xlate = irq_domain_xlate_onetwocell,
+};
+
+int __init __cp_intc_init(struct device_node *node,
+		struct device_node *parent)
+{
+	u32 num_irq		= davinci_soc_info.intc_irq_num;
 	u8 *irq_prio		= davinci_soc_info.intc_irq_prios;
 	u32 *host_map		= davinci_soc_info.intc_host_map;
 	unsigned num_reg	= BITS_TO_LONGS(num_irq);
-	int i;
+	int i, irq_base;
 
 	davinci_intc_type = DAVINCI_INTC_TYPE_CP_INTC;
-	davinci_intc_base = ioremap(davinci_soc_info.intc_base, SZ_8K);
+	if (node) {
+		davinci_intc_base = of_iomap(node, 0);
+		if (of_property_read_u32(node, "ti,intc-size", &num_irq))
+			pr_warn("unable to get intc-size, default to %d\n",
+				num_irq);
+	} else {
+		davinci_intc_base = ioremap(davinci_soc_info.intc_base,
+					SZ_8K);
+	}
 	if (WARN_ON(!davinci_intc_base))
-		return;
+		return -EINVAL;
 
 	cp_intc_write(0, CP_INTC_GLOBAL_ENABLE);
 
@@ -165,13 +197,48 @@ void __init cp_intc_init(void)
 		for (i = 0; host_map[i] != -1; i++)
 			cp_intc_write(host_map[i], CP_INTC_HOST_MAP(i));
 
-	/* Set up genirq dispatching for cp_intc */
-	for (i = 0; i < num_irq; i++) {
-		irq_set_chip(i, &cp_intc_irq_chip);
-		set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
-		irq_set_handler(i, handle_edge_irq);
+	if (node) {
+		irq_base = irq_alloc_descs(-1, 0, num_irq, 0);
+		if (irq_base < 0) {
+			pr_warn("Couldn't allocate IRQ numbers\n");
+			irq_base = 0;
+		}
+
+		/* create a legacy host */
+		cp_intc_domain = irq_domain_add_legacy(node, num_irq,
+					irq_base, 0, &cp_intc_host_ops, NULL);
+		if (cp_intc_domain == NULL) {
+			pr_err("CP INTC: failed to allocate irq host!\n");
+			return -EINVAL;
+		}
+	} else {
+		/* Set up genirq dispatching for cp_intc */
+		for (i = 0; i < num_irq; i++) {
+			irq_set_chip(i, &cp_intc_irq_chip);
+			set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
+			irq_set_handler(i, handle_edge_irq);
+		}
 	}
 
 	/* Enable global interrupt */
 	cp_intc_write(1, CP_INTC_GLOBAL_ENABLE);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static struct of_device_id irq_match[] __initdata = {
+	{ .compatible = "ti,cp_intc", .data = __cp_intc_init, },
+	{ }
+};
+
+void __init cp_intc_init(void)
+{
+	of_irq_init(irq_match);
+}
+#else
+void __init cp_intc_init(void)
+{
+	__cp_intc_init(NULL, NULL);
 }
+#endif
-- 
1.7.7.6