ipodvideo: detect ram size at boot (doesn't actually get USED yet)

This is the first step to allowing a single build which will work on any ipodvideo.

A global variable, probed_ramsize, is initialised to either 32 or 64 early in boot.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27937 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 11 insertions, 0 deletions

diff --git a/firmware/target/arm/system-pp502x.c b/firmware/target/arm/system-pp502x.c
index 9bedb0e42c..700686b427 100644
--- a/firmware/target/arm/system-pp502x.c
+++ b/firmware/target/arm/system-pp502x.c
@@ -42,6 +42,10 @@ extern void SERIAL0(void);
 static struct corelock cpufreq_cl SHAREDBSS_ATTR;
 #endif
 
+#if defined(IPOD_VIDEO) && !defined(BOOTLOADER)
+unsigned char probed_ramsize;
+#endif
+
 void __attribute__((interrupt("IRQ"))) irq_handler(void)
 {
     if(CURRENT_CORE == CPU)
@@ -518,6 +522,13 @@ void system_init(void)
 #else
         pp_set_cpu_frequency(CPUFREQ_MAX);
 #endif
+
+#if defined(IPOD_VIDEO)
+        /* crt0-pp.S wrote the ram size to the last byte of the first 32MB
+           ram bank. See the comment there for how we determine it. */
+        volatile unsigned char *end32 = (volatile unsigned char *)0x01ffffff;
+        probed_ramsize = *end32;
+#endif
     }
 
     init_cache();