[arch][or1k] add or1k (OpenRISC 1000) architecture

This add support for the OpenRISC 1000 architecture, and
as the architecture specification defines an on-chip tick-timer
and interrupt controller, drivers for those are included in
this commit.
Support to utilize the MMU is implemented,
and it can be opted in and out with WITH_KERNEL_VM

dev/interrupt/or1k_pic/or1k_pic.c

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2015 Stefan Kristiansson
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include <err.h>
+#include <debug.h>
+#include <kernel/thread.h>
+#include <platform/interrupts.h>
+#include <platform/pic.h>
+#include <arch/or1k.h>
+
+struct int_handler_struct {
+    int_handler handler;
+    void *arg;
+};
+
+static struct int_handler_struct int_handler_table[MAX_INT];
+
+void register_int_handler(unsigned int vector, int_handler handler, void *arg)
+{
+    if (vector >= MAX_INT)
+        panic("%s: vector out of range %d\n", __FUNCTION__, vector);
+
+    enter_critical_section();
+
+    int_handler_table[vector].handler = handler;
+    int_handler_table[vector].arg = arg;
+
+    exit_critical_section();
+}
+
+status_t mask_interrupt(unsigned int vector)
+{
+    if (vector >= MAX_INT)
+        return ERR_INVALID_ARGS;
+
+    mtspr(OR1K_SPR_PIC_PICMR_ADDR, mfspr(OR1K_SPR_PIC_PICMR_ADDR) & ~(1 << vector));
+
+    return NO_ERROR;
+}
+
+status_t unmask_interrupt(unsigned int vector)
+{
+    if (vector >= MAX_INT)
+        return ERR_INVALID_ARGS;
+
+    mtspr(OR1K_SPR_PIC_PICMR_ADDR, mfspr(OR1K_SPR_PIC_PICMR_ADDR) | (1 << vector));
+
+    return NO_ERROR;
+}
+
+enum handler_return platform_irq(void)
+{
+    enum handler_return ret = INT_NO_RESCHEDULE;
+
+    uint irq = __builtin_ffs(mfspr(OR1K_SPR_PIC_PICSR_ADDR)) - 1;
+
+    if (irq < MAX_INT && int_handler_table[irq].handler)
+        ret = int_handler_table[irq].handler(int_handler_table[irq].arg);
+
+    return ret;
+}

dev/interrupt/or1k_pic/rules.mk

@@ -0,0 +1,11 @@
+LOCAL_DIR := $(GET_LOCAL_DIR)
+
+MODULE := $(LOCAL_DIR)
+
+GLOBAL_INCLUDES += \
+	$(LOCAL_DIR)/include
+
+MODULE_SRCS += \
+	$(LOCAL_DIR)/or1k_pic.c
+
+include make/module.mk