From 82f9056988331572e01231d70fadc64b7ab76c6f Mon Sep 17 00:00:00 2001
From: Daniel Ankers <dan@weirdo.org.uk>
Date: Sun, 4 Mar 2007 20:06:41 +0000
Subject: Dual core support for PP502x players (iPod G4 and later, iriver h10,
 Sansa - iPod G3 will be coming soon.)  This allows threads to be run on
 either core provided that all communications between the cores is done using
 uncached memory.  There should be no significant change in battery life from
 doing this.  Documentation (on the RockboxKernel wiki page) will follow
 shortly.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@12601 a1c6a512-1295-4272-9138-f99709370657
---
 firmware/thread.c | 78 +++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 56 insertions(+), 22 deletions(-)

(limited to 'firmware/thread.c')

diff --git a/firmware/thread.c b/firmware/thread.c
index 2281f43e53..281ab0fa54 100644
--- a/firmware/thread.c
+++ b/firmware/thread.c
@@ -64,6 +64,10 @@ int *cop_stackend = stackend;
 #endif
 #endif
 
+#if (NUM_CORES > 1)
+bool IDATA_ATTR kernel_running_on_cop = false;
+#endif
+
 /* Conserve IRAM
 static void add_to_list(struct thread_entry **list,
                         struct thread_entry *thread) ICODE_ATTR;
@@ -316,10 +320,13 @@ static inline void sleep_core(void)
 #elif CONFIG_CPU == SH7034
         and_b(0x7F, &SBYCR);
         asm volatile ("sleep");
-#elif CONFIG_CPU == PP5020
+#elif defined (CPU_PP)
         /* This should sleep the CPU. It appears to wake by itself on
            interrupts */
-        CPU_CTL = 0x80000000;
+        if (CURRENT_CORE == CPU)
+            CPU_CTL = PROC_SLEEP;
+        else
+            COP_CTL = PROC_SLEEP;
 #elif CONFIG_CPU == S3C2440
         CLKCON |= (1 << 2); /* set IDLE bit */
         for(i=0; i<10; i++); /* wait for IDLE */
@@ -608,27 +615,16 @@ void wakeup_thread(struct thread_entry **list)
 }
 
 /*---------------------------------------------------------------------------
- * Create thread on the current core.
- * Return ID if context area could be allocated, else -1.
+ * Create a thread
+ * If using a dual core architecture, specify which core to start the thread
+ * on, and whether to fall back to the other core if it can't be created
+ * Return ID if context area could be allocated, else NULL.
  *---------------------------------------------------------------------------
  */
 struct thread_entry* 
     create_thread(void (*function)(void), void* stack, int stack_size,
-                  const char *name IF_PRIO(, int priority))
-{
-    return create_thread_on_core(CURRENT_CORE, function, stack, stack_size,
-                  name IF_PRIO(, priority));
-}
-
-/*---------------------------------------------------------------------------
- * Create thread on a specific core.
- * Return ID if context area could be allocated, else -1.
- *---------------------------------------------------------------------------
- */
-struct thread_entry* 
-    create_thread_on_core(unsigned int core, void (*function)(void), 
-                          void* stack, int stack_size,
-                          const char *name IF_PRIO(, int priority))
+                  const char *name IF_PRIO(, int priority)
+		  IF_COP(, unsigned int core, bool fallback))
 {
     unsigned int i;
     unsigned int stacklen;
@@ -637,6 +633,29 @@ struct thread_entry*
     struct regs *regs;
     struct thread_entry *thread;
 
+/*****
+ * Ugly code alert!
+ * To prevent ifdef hell while keeping the binary size down, we define
+ * core here if it hasn't been passed as a parameter
+ *****/
+#if NUM_CORES == 1
+#define core CPU
+#endif
+
+#if NUM_CORES > 1
+/* If the kernel hasn't initialised on the COP (most likely due to an old
+ * bootloader) then refuse to start threads on the COP
+ */
+    if((core == COP) && !kernel_running_on_cop)
+    {
+        if (fallback)
+            return create_thread(function, stack, stack_size, name
+	                         IF_PRIO(, priority) IF_COP(, CPU, false));
+	else
+            return NULL;
+    }
+#endif
+
     for (n = 0; n < MAXTHREADS; n++)
     {
         if (cores[core].threads[n].name == NULL)
@@ -644,8 +663,15 @@ struct thread_entry*
     }
     
     if (n == MAXTHREADS)
-        return NULL;
-    
+    {
+#if NUM_CORES > 1
+        if (fallback)
+	    return create_thread(function, stack, stack_size, name
+	                         IF_PRIO(, priority) IF_COP(, 1 - core, fallback));
+	else
+#endif
+            return NULL;
+    }
     
     /* Munge the stack to make it easy to spot stack overflows */
     stacklen = stack_size / sizeof(int);
@@ -677,6 +703,9 @@ struct thread_entry*
     THREAD_CPU_INIT(core, thread);
 
     return thread;
+#if NUM_CORES == 1
+#undef core
+#endif
 }
 
 #ifdef HAVE_SCHEDULER_BOOSTCTRL
@@ -751,7 +780,8 @@ void init_threads(void)
 {
     unsigned int core = CURRENT_CORE;
 
-    memset(cores, 0, sizeof cores);
+    if (core == CPU)
+        memset(cores, 0, sizeof cores);
     cores[core].sleeping = NULL;
     cores[core].running = NULL;
     cores[core].threads[0].name = main_thread_name;
@@ -779,6 +809,10 @@ void init_threads(void)
 #endif
     }
     cores[core].threads[0].context.start = 0; /* thread 0 already running */
+#if NUM_CORES > 1
+    if(core == COP)
+        kernel_running_on_cop = true; /* can we use context.start for this? */
+#endif
 }
 
 int thread_stack_usage(const struct thread_entry *thread)
-- 
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