From 5cc73474633f0f33e0b9f6a55cd8831df9bec906 Mon Sep 17 00:00:00 2001
From: Thom Johansen <thomj@rockbox.org>
Date: Sat, 17 Dec 2005 19:11:43 +0000
Subject: [PATCH] Raise iPod CPU frequency and enable cache and add function
 needed for button driver.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8257 a1c6a512-1295-4272-9138-f99709370657
---
 firmware/export/system.h |  5 +++++
 firmware/system.c        | 45 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/firmware/export/system.h b/firmware/export/system.h
index e4de5889c5..40e3884b16 100644
--- a/firmware/export/system.h
+++ b/firmware/export/system.h
@@ -34,6 +34,11 @@ extern long cpu_frequency;
 #define outl(a,b) (*(volatile unsigned long *) (b) = (a))
 #define inb(a) (*(volatile unsigned char *) (a))
 #define outb(a,b) (*(volatile unsigned char *) (b) = (a))
+static inline void udelay(unsigned usecs)
+{
+    unsigned start = inl(0x60005010);
+    while ((inl(0x60005010) - start) < usecs);
+}
 #endif
 
 #ifdef HAVE_ADJUSTABLE_CPU_FREQ
diff --git a/firmware/system.c b/firmware/system.c
index 2c7c6f376d..cbc009aa78 100644
--- a/firmware/system.c
+++ b/firmware/system.c
@@ -1117,6 +1117,49 @@ void irq(void)
         ipod_4g_button_int();
 }
 
+/* TODO: The following two function have been lifted straight from IPL, and
+   hence have a lot of numeric addresses used straight. I'd like to use
+   #defines for these, but don't know what most of them are for or even what
+   they should be named. Because of this I also have no way of knowing how
+   to extend the funtions to do alternate cache configurations and/or 
+   some other CPU frequency scaling. */
+
+static void ipod_init_cache(void)
+{
+    unsigned i;
+
+    /* cache init mode? */
+    outl(0x4, 0x6000C000);
+
+    /* PP5002 has 8KB cache */
+    for (i = 0xf0004000; i < 0xf0006000; i += 16) {
+        outl(0x0, i);
+    }
+
+    outl(0x0, 0xf000f040);
+    outl(0x3fc0, 0xf000f044);
+
+    /* enable cache */
+    outl(0x1, 0x6000C000);
+
+    for (i = 0x10000000; i < 0x10002000; i += 16)
+        inb(i);
+}
+    
+static void ipod_set_cpu_speed(void)
+{
+    outl(inl(0x70000020) | (1<<30), 0x70000020);
+
+    /* Set run state to 24MHz */
+    outl((inl(0x60006020) & 0x0fffff0f) | 0x20000020, 0x60006020);
+
+    /* 75 MHz (24/8)*25 */
+    outl(0xaa021908, 0x60006034);
+    udelay(2000);
+
+    outl((inl(0x60006020) & 0x0fffff0f) | 0x20000070, 0x60006020);
+}
+
 void system_init(void)
 {
     /* disable all irqs */
@@ -1127,6 +1170,8 @@ void system_init(void)
     outl(-1, 0x60001038);
     outl(-1, 0x60001028);
     outl(-1, 0x6000101c);
+    ipod_set_cpu_speed();
+    ipod_init_cache();
 }
 
 void system_reboot(void)