From 94c06c7e95943bdf4ae57c6250f9352661ac4d56 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C3=ABl=20Carr=C3=A9?= <rafael.carre@gmail.com>
Date: Thu, 6 Nov 2008 14:34:37 +0000
Subject: [PATCH] AS3525: implement tick_start() with TIMER2

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@19027 a1c6a512-1295-4272-9138-f99709370657
---
 firmware/export/as3525.h                   |  8 ++++++
 firmware/target/arm/as3525/kernel-as3525.c | 31 +++++++++++++++++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/firmware/export/as3525.h b/firmware/export/as3525.h
index 8d81997b94..245f4ae963 100644
--- a/firmware/export/as3525.h
+++ b/firmware/export/as3525.h
@@ -283,6 +283,14 @@ interface */
 #define TIMER1_MIS       (*(volatile unsigned long*)(TIMER_BASE + 0x14)) /*  1 bit width */
 #define TIMER1_BGLOAD    (*(volatile unsigned long*)(TIMER_BASE + 0x18)) /* 32-bit width */
 
+#define TIMER2_LOAD      (*(volatile unsigned long*)(TIMER_BASE + 0x20)) /* 32-bit width */
+#define TIMER2_VALUE     (*(volatile unsigned long*)(TIMER_BASE + 0x24)) /* 32 bit width */
+#define TIMER2_CONTROL   (*(volatile unsigned long*)(TIMER_BASE + 0x28)) /*  8 bit width */
+#define TIMER2_INTCLR    (*(volatile unsigned long*)(TIMER_BASE + 0x2C)) /* clears ir by write access */
+#define TIMER2_RIS       (*(volatile unsigned long*)(TIMER_BASE + 0x30)) /*  1 bit width */
+#define TIMER2_MIS       (*(volatile unsigned long*)(TIMER_BASE + 0x34)) /*  1 bit width */
+#define TIMER2_BGLOAD    (*(volatile unsigned long*)(TIMER_BASE + 0x38)) /* 32-bit width */
+
 /**
 * Counter/Timer control register bits
 **/
diff --git a/firmware/target/arm/as3525/kernel-as3525.c b/firmware/target/arm/as3525/kernel-as3525.c
index c0f404efbd..08d6128bb7 100644
--- a/firmware/target/arm/as3525/kernel-as3525.c
+++ b/firmware/target/arm/as3525/kernel-as3525.c
@@ -21,8 +21,37 @@
 #include "config.h"
 #include "system.h"
 #include "kernel.h"
+#include "panic.h"
+
+void INT_TIMER2(void)
+{
+    call_tick_tasks();  /* Run through the list of tick tasks */
+
+    TIMER2_INTCLR = 0;  /* clear interrupt */
+}
 
 void tick_start(unsigned int interval_in_ms)
 {
-    (void)interval_in_ms;
+    int phi = 0;                            /* prescaler bits */
+    int prescale = 1;
+    int cycles = 64000 * interval_in_ms;    /* pclk is clocked at 64MHz */
+
+    while(cycles > 0x10000)
+    {
+        phi++;
+        prescale <<= 4;
+        cycles >>= 4;
+    }
+
+    if(prescale > 256)
+        panicf("%s : interval too big", __func__);
+
+    CGU_PERI |= CGU_TIMER2_CLOCK_ENABLE;    /* enable peripheral */
+    VIC_INT_ENABLE = INTERRUPT_TIMER2;      /* enable interrupt */
+
+    TIMER2_LOAD = TIMER2_BGLOAD = cycles;   /* timer period */
+
+    /* /!\ bit 4 (reserved) must not be modified
+     * periodic mode, interrupt enabled, 16 bits counter */
+    TIMER2_CONTROL = (TIMER2_CONTROL & (1<<4)) | 0xe0 | (phi<<2);
 }