Initial work for coprocessor support on iPods. FS#5755

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@10437 a1c6a512-1295-4272-9138-f99709370657

apps/main.c

@@ -451,6 +451,19 @@ void init(void)
 #endif
 }
 
+void cop_main(void)
+{
+/* This is the entry point for the coprocessor
+   Anyone not running an upgraded bootloader will never reach this point,
+   so it should not be assumed that the coprocessor be usable even on
+   platforms which support it.
+
+   At present all we do is send the COP to sleep if anything wakes it. */
+    while(1) {
+        COP_CTL = PROC_SLEEP;
+    }
+}
+
 int main(void)
 {
     app_main();

bootloader/ipod.c

@@ -425,16 +425,7 @@ void* main(void)
             lcd_puts(0, line++, "Rockbox loaded.");
             lcd_update();
             memcpy((void*)DRAM_START,loadbuffer,rc);
-
-            /* Transfer execution directly to Rockbox - we don't want
-               to run the rest of the bootloader startup code. */
-            asm volatile(
-                "mov   r0, #" SC(DRAM_START) "\n"
-                "mov   pc, r0                 \n"
-            );
-
-            /* We don't get here, but keep the compiler happy. */
-            return (void*)0;
+            return (void*)DRAM_START;
         }
     }
 

firmware/app.lds

@@ -257,6 +257,15 @@ SECTIONS
        . += 0x2000;
        stackend = .;
     } > IRAM
+    
+    .cop_stack :
+    {
+       *(.cop_stack)
+       cop_stackbegin = .;
+       . += 0x0500;
+       cop_stackend = .;
+    } > IRAM
+
 #else
     /* TRICK ALERT! We want 0x2000 bytes of stack, but we set the section
        size smaller, and allow the stack to grow into the .iram copy */

firmware/crt0.S

@@ -36,11 +36,15 @@ start:
  * Copyright (c) 2005, Bernard Leach <leachbj@bouncycastle.org>
  *
  */
+    .equ    PP5002_PROC_ID,  0xc4000000
+    .equ    PP5002_COP_CTRL, 0xcf004058
+    .equ    PP5020_PROC_ID,  0x60000000
+    .equ    PP5020_COP_CTRL, 0x60007004
 
     msr    cpsr_c, #0xd3 /* enter supervisor mode, disable IRQ */
 
 #ifndef BOOTLOADER
-#if CONFIG_CPU == PP5002 || CONFIG_CPU == PP5020
+#ifdef CPU_PP
     b      pad_skip
 .space 50*4 /* (more than enough) space for exception vectors */
 pad_skip:
@@ -81,6 +85,34 @@ remap_start:
 L_post_remap: .word remap_end
 remap_end:
 
+#ifdef CPU_PP 
+    /* After doing the remapping, send the COP to sleep.
+       On wakeup it will go to cop_init */
+#if CONFIG_CPU == PP5002
+    ldr    r0, =PP5002_PROC_ID
+#else
+    ldr    r0, =PP5020_PROC_ID
+#endif
+    ldr    r0, [r0]
+    and    r0, r0, #0xff
+    cmp    r0, #0x55
+    beq    1f
+    
+    /* put us (co-processor) to sleep */
+#if CONFIG_CPU == PP5002
+    ldr    r4, =PP5002_COP_CTRL
+    mov    r3, #0xca
+#else
+    ldr    r4, =PP5020_COP_CTRL
+    mov    r3, #0x80000000
+#endif
+    str    r3, [r4]
+
+    ldr    pc, =cop_init
+
+1:
+#endif
+
 #elif CONFIG_CPU == PNX0101
 
 #ifndef DEBUG
@@ -167,10 +199,6 @@ remap_end:
 
 #ifdef BOOTLOADER
 #ifdef CPU_PP
-    .equ    PP5002_PROC_ID,  0xc4000000
-    .equ    PP5002_COP_CTRL, 0xcf004058
-    .equ    PP5020_PROC_ID,  0x60000000
-    .equ    PP5020_COP_CTRL, 0x60007004
     /* TODO: the high part of the address is probably dependent on CONFIG_CPU.
        Since we tend to use ifdefs for each chipset target
        anyway, we might as well just hardcode it here.
@@ -306,6 +334,35 @@ boot_table:
     bl     main
     /* main() should never return */
 
+#ifdef CPU_PP
+cop_init:
+    ldr    sp, =cop_stackend
+    mov    r3, sp
+    ldr    r2, =cop_stackbegin
+    ldr    r4, =0xdeadbeef
+2:
+    cmp    r3, r2
+    strhi  r4, [r2], #4
+    bhi    2b
+
+    ldr    sp, =cop_stackend
+    bl     cop_main
+#else
+    /* If we don't plan to use the COP, we have some code to catch it and send
+       it back to sleep if somebody wakes it.  This means that the firmware
+       size doesn't grow too much while the COP is still unused, but it is
+       still handled cleanly. */
+#if CONFIG_CPU==PP5002
+    ldr    r4, =PP5002_COP_CTRL
+    mov    r3, #0xca
+#else
+    ldr    r4, =PP5020_COP_CTRL
+    mov    r3, #0x80000000
+#endif
+    str    r3, [r4]
+    ldr    pc, =cop_init    
+#endif   /* PP specific */
+    
 /* Exception handlers. Will be copied to address 0 after memory remapping */
     .section .vectors,"aw"
     ldr    pc, [pc, #24]

firmware/export/pp5002.h

@@ -20,6 +20,8 @@
 #define __PP5002_H__
 
 /* All info gleaned and/or copied from the iPodLinux project. */
+#define CPU_CTL          (*(volatile unsigned char *)(0xcf004054))
+#define COP_CTL          (*(volatile unsigned char *)(0xcf004058))
 
 #define GPIOA_ENABLE     (*(volatile unsigned char *)(0xcf000000))
 #define GPIOB_ENABLE     (*(volatile unsigned char *)(0xcf000004))
@@ -98,4 +100,7 @@
 #define SER1_MASK    (1 << SER1_IRQ)
 #define DMA_OUT_MASK (1 << DMA_OUT_IRQ)
 
+#define PROC_SLEEP   0xca
+#define PROC_WAKE    0xce
+
 #endif

firmware/export/pp5020.h

@@ -165,4 +165,7 @@
 #define IISFIFO_WR          (*(volatile unsigned long*)(0x70002840))
 #define IISFIFO_RD          (*(volatile unsigned long*)(0x70002880))
 
+#define PROC_SLEEP   0x80000000
+#define PROC_WAKE    0x0
+
 #endif