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Diffstat (limited to 'arch/mips/gt64120/common/time.c')
-rw-r--r--arch/mips/gt64120/common/time.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/arch/mips/gt64120/common/time.c b/arch/mips/gt64120/common/time.c
new file mode 100644
index 000000000000..2287b59536e5
--- /dev/null
+++ b/arch/mips/gt64120/common/time.c
@@ -0,0 +1,100 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * Galileo Technology chip interrupt handler
+ */
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/kernel_stat.h>
+#include <asm/ptrace.h>
+#include <asm/gt64120.h>
+
+/*
+ * These are interrupt handlers for the GT on-chip interrupts. They all come
+ * in to the MIPS on a single interrupt line, and have to be handled and ack'ed
+ * differently than other MIPS interrupts.
+ */
+
+static void gt64120_irq(int irq, void *dev_id, struct pt_regs *regs)
+{
+ unsigned int irq_src, int_high_src, irq_src_mask, int_high_src_mask;
+ int handled = 0;
+
+ irq_src = GT_READ(GT_INTRCAUSE_OFS);
+ irq_src_mask = GT_READ(GT_INTRMASK_OFS);
+ int_high_src = GT_READ(GT_HINTRCAUSE_OFS);
+ int_high_src_mask = GT_READ(GT_HINTRMASK_OFS);
+ irq_src = irq_src & irq_src_mask;
+ int_high_src = int_high_src & int_high_src_mask;
+
+ if (irq_src & 0x00000800) { /* Check for timer interrupt */
+ handled = 1;
+ irq_src &= ~0x00000800;
+ do_timer(regs);
+#ifndef CONFIG_SMP
+ update_process_times(user_mode(regs));
+#endif
+ }
+
+ GT_WRITE(GT_INTRCAUSE_OFS, 0);
+ GT_WRITE(GT_HINTRCAUSE_OFS, 0);
+}
+
+/*
+ * Initializes timer using galileo's built in timer.
+ */
+#ifdef CONFIG_SYSCLK_100
+#define Sys_clock (100 * 1000000) // 100 MHz
+#endif
+#ifdef CONFIG_SYSCLK_83
+#define Sys_clock (83.333 * 1000000) // 83.333 MHz
+#endif
+#ifdef CONFIG_SYSCLK_75
+#define Sys_clock (75 * 1000000) // 75 MHz
+#endif
+
+/*
+ * This will ignore the standard MIPS timer interrupt handler that is passed in
+ * as *irq (=irq0 in ../kernel/time.c). We will do our own timer interrupt
+ * handling.
+ */
+void gt64120_time_init(void)
+{
+ static struct irqaction timer;
+
+ /* Disable timer first */
+ GT_WRITE(GT_TC_CONTROL_OFS, 0);
+ /* Load timer value for 100 Hz */
+ GT_WRITE(GT_TC3_OFS, Sys_clock / 100);
+
+ /*
+ * Create the IRQ structure entry for the timer. Since we're too early
+ * in the boot process to use the "request_irq()" call, we'll hard-code
+ * the values to the correct interrupt line.
+ */
+ timer.handler = gt64120_irq;
+ timer.flags = SA_SHIRQ | SA_INTERRUPT;
+ timer.name = "timer";
+ timer.dev_id = NULL;
+ timer.next = NULL;
+ timer.mask = CPU_MASK_NONE;
+ irq_desc[GT_TIMER].action = &timer;
+
+ enable_irq(GT_TIMER);
+
+ /* Enable timer ints */
+ GT_WRITE(GT_TC_CONTROL_OFS, 0xc0);
+ /* clear Cause register first */
+ GT_WRITE(GT_INTRCAUSE_OFS, 0x0);
+ /* Unmask timer int */
+ GT_WRITE(GT_INTRMASK_OFS, 0x800);
+ /* Clear High int register */
+ GT_WRITE(GT_HINTRCAUSE_OFS, 0x0);
+ /* Mask All interrupts at High cause interrupt */
+ GT_WRITE(GT_HINTRMASK_OFS, 0x0);
+}