ARC: [plat-arcfpga]: Enabling DeviceTree for Angel4 board

* arc-uart platform device now populated dynamically, using
  of_platform_populate() - applies to any other device whatsoever.

* uart in turn requires incore arc-intc to be also present in DT

* A irq-domain needs to be instantiated for IRQ requests by DT probed
  device (e.g. arc-uart)

TODO: switch over to linear irq domain once all devs have been
      transitioned to DT

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Arnd Bergmann <arnd@arndb.de>

6 files changed, 170 insertions, 58 deletions

diff --git a/Documentation/devicetree/bindings/arc/interrupts.txt b/Documentation/devicetree/bindings/arc/interrupts.txt
new file mode 100644
index 000000000000..9a5d562435ea
--- /dev/null
+++ b/Documentation/devicetree/bindings/arc/interrupts.txt
@@ -0,0 +1,24 @@
+* ARC700 incore Interrupt Controller
+
+  The core interrupt controller provides 32 prioritised interrupts (2 levels)
+  to ARC700 core.
+
+Properties:
+
+- compatible: "snps,arc700-intc"
+- interrupt-controller: This is an interrupt controller.
+- #interrupt-cells: Must be <1>.
+
+  Single Cell "interrupts" property of a device specifies the IRQ number
+  between 0 to 31
+
+  intc accessed via the special ARC AUX register interface, hence "reg" property
+  is not specified.
+
+Example:
+
+        intc: interrupt-controller {
+                compatible = "snps,arc700-intc";
+                interrupt-controller;
+                #interrupt-cells = <1>;
+        };
diff --git a/arch/arc/boot/dts/Makefile b/arch/arc/boot/dts/Makefile
index 17dc7b8b05fa..5776835d583f 100644
--- a/arch/arc/boot/dts/Makefile
+++ b/arch/arc/boot/dts/Makefile
@@ -1,5 +1,5 @@
 # Built-in dtb
-builtindtb-y            := skeleton
+builtindtb-y            := angel4
 
 ifneq ($(CONFIG_ARC_BUILTIN_DTB_NAME),"")
         builtindtb-y    := $(patsubst "%",%,$(CONFIG_ARC_BUILTIN_DTB_NAME))
diff --git a/arch/arc/boot/dts/angel4.dts b/arch/arc/boot/dts/angel4.dts
new file mode 100644
index 000000000000..4c188d5bc10c
--- /dev/null
+++ b/arch/arc/boot/dts/angel4.dts
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+/dts-v1/;
+
+/include/ "skeleton.dtsi"
+
+/ {
+        compatible = "snps,arc-angel4";
+        clock-frequency = <80000000>;   /* 80 MHZ */
+        #address-cells = <1>;
+        #size-cells = <1>;
+        interrupt-parent = <&intc>;
+
+        chosen {
+                bootargs = "console=ttyARC0,115200n8";
+        };
+
+        aliases {
+                serial0 = &arcuart0;
+        };
+
+        memory {
+                device_type = "memory";
+                reg = <0x00000000 0x10000000>;  /* 256M */
+        };
+
+        fpga {
+                compatible = "simple-bus";
+                #address-cells = <1>;
+                #size-cells = <1>;
+
+                /* child and parent address space 1:1 mapped */
+                ranges;
+
+                intc: interrupt-controller {
+                        compatible = "snps,arc700-intc";
+                        interrupt-controller;
+                        #interrupt-cells = <1>;
+                };
+
+                arcuart0: serial@c0fc1000 {
+                        compatible = "snps,arc-uart";
+                        reg = <0xc0fc1000 0x100>;
+                        interrupts = <5>;
+                        clock-frequency = <80000000>;
+                        baud = <115200>;
+                        status = "okay";
+                };
+        };
+};
diff --git a/arch/arc/boot/dts/skeleton.dtsi b/arch/arc/boot/dts/skeleton.dtsi
index eb8b77367352..a870bdd5e404 100644
--- a/arch/arc/boot/dts/skeleton.dtsi
+++ b/arch/arc/boot/dts/skeleton.dtsi
@@ -18,6 +18,18 @@
         #size-cells = <1>;
         chosen { };
         aliases { };
+
+        cpus {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                cpu@0 {
+                        device_type = "cpu";
+                        compatible = "snps,arc770d";
+                        reg = <0>;
+                };
+        };
+
         memory {
                 device_type = "memory";
                 reg = <0x00000000 0x10000000>;  /* 256M */
diff --git a/arch/arc/kernel/irq.c b/arch/arc/kernel/irq.c
index 2f399eb88f9d..3c18e66386c7 100644
--- a/arch/arc/kernel/irq.c
+++ b/arch/arc/kernel/irq.c
@@ -9,6 +9,8 @@
 
 #include <linux/interrupt.h>
 #include <linux/module.h>
+#include <linux/of.h>
+#include <linux/irqdomain.h>
 #include <asm/sections.h>
 #include <asm/irq.h>
 
@@ -59,16 +61,40 @@ static struct irq_chip onchip_intc = {
         .irq_unmask     = arc_unmask_irq,
 };
 
+static int arc_intc_domain_map(struct irq_domain *d, unsigned int irq,
+                                irq_hw_number_t hw)
+{
+        if (irq == TIMER0_IRQ)
+                irq_set_chip_and_handler(irq, &onchip_intc, handle_percpu_irq);
+        else
+                irq_set_chip_and_handler(irq, &onchip_intc, handle_level_irq);
+
+        return 0;
+}
+
+static const struct irq_domain_ops arc_intc_domain_ops = {
+        .xlate = irq_domain_xlate_onecell,
+        .map = arc_intc_domain_map,
+};
+
+static struct irq_domain *root_domain;
+
 void __init init_onchip_IRQ(void)
 {
-        int i;
+        struct device_node *intc = NULL;
+
+        intc = of_find_compatible_node(NULL, NULL, "snps,arc700-intc");
+        if(!intc)
+                panic("DeviceTree Missing incore intc\n");
+
+        root_domain = irq_domain_add_legacy(intc, NR_IRQS, 0, 0,
+                                            &arc_intc_domain_ops, NULL);
 
-        for (i = 0; i < NR_IRQS; i++)
-                irq_set_chip_and_handler(i, &onchip_intc, handle_level_irq);
+        if (!root_domain)
+                panic("root irq domain not avail\n");
 
-#ifdef CONFIG_SMP
-        irq_set_chip_and_handler(TIMER0_IRQ, &onchip_intc, handle_percpu_irq);
-#endif
+        /* with this we don't need to export root_domain */
+        irq_set_default_host(root_domain);
 }
 
 /*
diff --git a/arch/arc/plat-arcfpga/platform.c b/arch/arc/plat-arcfpga/platform.c
index 5388b31e2ead..33bcac8bd6b8 100644
--- a/arch/arc/plat-arcfpga/platform.c
+++ b/arch/arc/plat-arcfpga/platform.c
@@ -13,6 +13,7 @@
 #include <linux/device.h>
 #include <linux/platform_device.h>
 #include <linux/console.h>
+#include <linux/of_platform.h>
 #include <asm/setup.h>
 #include <asm/irq.h>
 #include <asm/clk.h>
@@ -20,58 +21,56 @@
 
 /*----------------------- Platform Devices -----------------------------*/
 
-#if defined(CONFIG_SERIAL_ARC) || defined(CONFIG_SERIAL_ARC_MODULE)
-
 static unsigned long arc_uart_info[] = {
-        CONFIG_ARC_SERIAL_BAUD, /* uart->baud */
-        -1,                     /* uart->port.uartclk */
-        -1,                     /* uart->is_emulated (runtime @running_on_hw) */
+        0,      /* uart->is_emulated (runtime @running_on_hw) */
+        0,      /* uart->port.uartclk */
+        0,      /* uart->baud */
         0
 };
 
-#define ARC_UART_DEV(n)                                 \
-                                                        \
-static struct resource arc_uart##n##_res[] = {          \
-        {                                               \
-                .start = UART##n##_BASE,                        \
-                .end   = UART##n##_BASE + 0xFF,         \
-                .flags = IORESOURCE_MEM,                \
-        },                                              \
-        {                                               \
-                .start = UART##n##_IRQ,                 \
-                .end   = UART##n##_IRQ,                 \
-                .flags = IORESOURCE_IRQ,                \
-        },                                              \
-};                                                      \
-                                                        \
-static struct platform_device arc_uart##n##_dev = {     \
-        .name = "arc-uart",                             \
-        .id = n,                                        \
-        .num_resources = ARRAY_SIZE(arc_uart##n##_res), \
-        .resource = arc_uart##n##_res,                  \
-        .dev = {                                        \
-                .platform_data = &arc_uart_info,        \
-        },                                              \
-}
+#if defined(CONFIG_SERIAL_ARC_CONSOLE)
+/*
+ * static platform data - but only for early serial
+ * TBD: derive this from a special DT node
+ */
+static struct resource arc_uart0_res[] = {
+        {
+                .start = UART0_BASE,
+                .end   = UART0_BASE + 0xFF,
+                .flags = IORESOURCE_MEM,
+        },
+        {
+                .start = UART0_IRQ,
+                .end   = UART0_IRQ,
+                .flags = IORESOURCE_IRQ,
+        },
+};
 
-ARC_UART_DEV(0);
-#if CONFIG_SERIAL_ARC_NR_PORTS > 1
-ARC_UART_DEV(1);
-#endif
+static struct platform_device arc_uart0_dev = {
+        .name = "arc-uart",
+        .id = 0,
+        .num_resources = ARRAY_SIZE(arc_uart0_res),
+        .resource = arc_uart0_res,
+        .dev = {
+                .platform_data = &arc_uart_info,
+        },
+};
 
 static struct platform_device *fpga_early_devs[] __initdata = {
-#if defined(CONFIG_SERIAL_ARC_CONSOLE)
         &arc_uart0_dev,
-#endif
 };
+#endif
 
 static void arc_fpga_serial_init(void)
 {
+        /* To let driver workaround ISS bug: baudh Reg can't be set to 0 */
+        arc_uart_info[0] = !running_on_hw;
+
         arc_uart_info[1] = arc_get_core_freq();
 
-        /* To let driver workaround ISS bug: baudh Reg can't be set to 0 */
-        arc_uart_info[2] = !running_on_hw;
+        arc_uart_info[2] = CONFIG_ARC_SERIAL_BAUD;
 
+#if defined(CONFIG_SERIAL_ARC_CONSOLE)
         early_platform_add_devices(fpga_early_devs,
                                    ARRAY_SIZE(fpga_early_devs));
 
@@ -97,16 +96,9 @@ static void arc_fpga_serial_init(void)
          * otherwise the early console never gets a chance to run.
          */
         add_preferred_console("ttyARC", 0, "115200");
+#endif
 }
 
-#else
-
-static void arc_fpga_serial_init(void)
-{
-}
-
-#endif  /* CONFIG_SERIAL_ARC */
-
 /*
  * Early Platform Initialization called from setup_arch()
  */
@@ -117,20 +109,23 @@ void __init arc_platform_early_init(void)
         arc_fpga_serial_init();
 }
 
-static struct platform_device *fpga_devs[] __initdata = {
+static struct of_dev_auxdata plat_auxdata_lookup[] __initdata = {
 #if defined(CONFIG_SERIAL_ARC) || defined(CONFIG_SERIAL_ARC_MODULE)
-        &arc_uart0_dev,
-#if CONFIG_SERIAL_ARC_NR_PORTS > 1
-        &arc_uart1_dev,
-#endif
+        OF_DEV_AUXDATA("snps,arc-uart", UART0_BASE, "arc-uart", arc_uart_info),
 #endif
+        {}
 };
 
 int __init fpga_plat_init(void)
 {
         pr_info("[plat-arcfpga]: registering device resources\n");
 
-        platform_add_devices(fpga_devs, ARRAY_SIZE(fpga_devs));
+        /*
+         * Traverses flattened DeviceTree - registering platform devices
+         * complete with their resources
+         */
+        of_platform_populate(NULL, of_default_bus_match_table,
+                             plat_auxdata_lookup, NULL);
 
         return 0;
 }