X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Farm%2Fmach-ebsa110%2Fcore.c;h=07c556392a0344e9ca16958c4947cdbd06822bf5;hb=9bf4aaab3e101692164d49b7ca357651eb691cb6;hp=5c14e04eae1be69e124f8d6b4e3b2d0d00c8c44b;hpb=db216c3d5e4c040e557a50f8f5d35d5c415e8c1c;p=linux-2.6.git

diff --git a/arch/arm/mach-ebsa110/core.c b/arch/arm/mach-ebsa110/core.c
index 5c14e04ea..07c556392 100644
--- a/arch/arm/mach-ebsa110/core.c
+++ b/arch/arm/mach-ebsa110/core.c
@@ -11,6 +11,7 @@
  */
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/interrupt.h>
 #include <linux/init.h>
 
 #include <asm/hardware.h>
@@ -26,6 +27,8 @@
 #include <asm/mach/irq.h>
 #include <asm/mach/map.h>
 
+#include <asm/mach/time.h>
+
 #define IRQ_MASK		0xfe000000	/* read */
 #define IRQ_MSET		0xfe000000	/* write */
 #define IRQ_STAT		0xff000000	/* read */
@@ -89,6 +92,103 @@ static void __init ebsa110_map_io(void)
 	iotable_init(ebsa110_io_desc, ARRAY_SIZE(ebsa110_io_desc));
 }
 
+
+#define PIT_CTRL		(PIT_BASE + 0x0d)
+#define PIT_T2			(PIT_BASE + 0x09)
+#define PIT_T1			(PIT_BASE + 0x05)
+#define PIT_T0			(PIT_BASE + 0x01)
+
+/*
+ * This is the rate at which your MCLK signal toggles (in Hz)
+ * This was measured on a 10 digit frequency counter sampling
+ * over 1 second.
+ */
+#define MCLK	47894000
+
+/*
+ * This is the rate at which the PIT timers get clocked
+ */
+#define CLKBY7	(MCLK / 7)
+
+/*
+ * This is the counter value.  We tick at 200Hz on this platform.
+ */
+#define COUNT	((CLKBY7 + (HZ / 2)) / HZ)
+
+/*
+ * Get the time offset from the system PIT.  Note that if we have missed an
+ * interrupt, then the PIT counter will roll over (ie, be negative).
+ * This actually works out to be convenient.
+ */
+static unsigned long ebsa110_gettimeoffset(void)
+{
+	unsigned long offset, count;
+
+	__raw_writeb(0x40, PIT_CTRL);
+	count = __raw_readb(PIT_T1);
+	count |= __raw_readb(PIT_T1) << 8;
+
+	/*
+	 * If count > COUNT, make the number negative.
+	 */
+	if (count > COUNT)
+		count |= 0xffff0000;
+
+	offset = COUNT;
+	offset -= count;
+
+	/*
+	 * `offset' is in units of timer counts.  Convert
+	 * offset to units of microseconds.
+	 */
+	offset = offset * (1000000 / HZ) / COUNT;
+
+	return offset;
+}
+
+static irqreturn_t
+ebsa110_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	u32 count;
+
+	/* latch and read timer 1 */
+	__raw_writeb(0x40, PIT_CTRL);
+	count = __raw_readb(PIT_T1);
+	count |= __raw_readb(PIT_T1) << 8;
+
+	count += COUNT;
+
+	__raw_writeb(count & 0xff, PIT_T1);
+	__raw_writeb(count >> 8, PIT_T1);
+
+	timer_tick(regs);
+
+	return IRQ_HANDLED;
+}
+
+static struct irqaction ebsa110_timer_irq = {
+	.name		= "EBSA110 Timer Tick",
+	.flags		= SA_INTERRUPT,
+	.handler	= ebsa110_timer_interrupt
+};
+
+/*
+ * Set up timer interrupt.
+ */
+static void __init ebsa110_init_time(void)
+{
+	/*
+	 * Timer 1, mode 2, LSB/MSB
+	 */
+	__raw_writeb(0x70, PIT_CTRL);
+	__raw_writeb(COUNT & 0xff, PIT_T1);
+	__raw_writeb(COUNT >> 8, PIT_T1);
+
+	gettimeoffset = ebsa110_gettimeoffset;
+
+	setup_irq(IRQ_EBSA110_TIMER0, &ebsa110_timer_irq);
+}
+
 MACHINE_START(EBSA110, "EBSA110")
 	MAINTAINER("Russell King")
 	BOOT_MEM(0x00000000, 0xe0000000, 0xe0000000)
@@ -98,4 +198,5 @@ MACHINE_START(EBSA110, "EBSA110")
 	SOFT_REBOOT
 	MAPIO(ebsa110_map_io)
 	INITIRQ(ebsa110_init_irq)
+	INITTIME(ebsa110_init_time)
 MACHINE_END