Merge branch 'master' of /home/wd/git/u-boot/master/

1 files changed, 369 insertions, 0 deletions

diff --git a/examples/standalone/sched.c b/examples/standalone/sched.c
new file mode 100644
index 0000000..b32766f
--- /dev/null
+++ b/examples/standalone/sched.c
@@ -0,0 +1,369 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <exports.h>
+
+/*
+ * Author: Arun Dharankar <ADharankar@ATTBI.Com>
+ *
+ * A very simple thread/schedular model:
+ *   - only one master thread, and no parent child relation maintained
+ *   - parent thread cannot be stopped or deleted
+ *   - no permissions or credentials
+ *   - no elaborate safety checks
+ *   - cooperative multi threading
+ *   - Simple round-robin scheduleing with no priorities
+ *   - no metering/statistics collection
+ *
+ * Basic idea of implementing this is to allow more than one tests to
+ * execute "simultaneously".
+ *
+ * This may be modified such thread_yield may be called in syscalls, and
+ * timer interrupts.
+ */
+
+
+#define MAX_THREADS 8
+
+#define CTX_SIZE 512
+#define STK_SIZE 8*1024
+
+#define STATE_EMPTY 0
+#define STATE_RUNNABLE 1
+#define STATE_STOPPED 2
+#define STATE_TERMINATED 2
+
+#define MASTER_THREAD 0
+
+#define RC_FAILURE	(-1)
+#define	RC_SUCCESS	(0)
+
+typedef	vu_char *jmp_ctx;
+unsigned long setctxsp (vu_char *sp);
+int ppc_setjmp(jmp_ctx env);
+void ppc_longjmp(jmp_ctx env, int val);
+#define setjmp	ppc_setjmp
+#define longjmp	ppc_longjmp
+
+struct lthread {
+	int state;
+	int retval;
+	char stack[STK_SIZE];
+	uchar context[CTX_SIZE];
+	int (*func) (void *);
+	void *arg;
+};
+static volatile struct lthread lthreads[MAX_THREADS];
+static volatile int current_tid = MASTER_THREAD;
+
+
+static uchar dbg = 0;
+
+#define PDEBUG(fmt, args...)	 {					\
+	if(dbg != 0) {							\
+		printf("[%s %d %s]: ",__FILE__,__LINE__,__FUNCTION__);\
+		printf(fmt, ##args);				\
+		printf("\n");					\
+	}								\
+}
+
+static int testthread (void *);
+static void sched_init (void);
+static int thread_create (int (*func) (void *), void *arg);
+static int thread_start (int id);
+static void thread_yield (void);
+static int thread_delete (int id);
+static int thread_join (int *ret);
+
+#if 0							/* not used yet */
+static int thread_stop (int id);
+#endif							/* not used yet */
+
+/* An example of schedular test */
+
+#define NUMTHREADS 7
+int sched (int ac, char *av[])
+{
+	int i, j;
+	int tid[NUMTHREADS];
+	int names[NUMTHREADS];
+
+	app_startup(av);
+
+	sched_init ();
+
+	for (i = 0; i < NUMTHREADS; i++) {
+		names[i] = i;
+		j = thread_create (testthread, (void *) &names[i]);
+		if (j == RC_FAILURE)
+			printf ("schedtest: Failed to create thread %d\n", i);
+		if (j > 0) {
+			printf ("schedtest: Created thread with id %d, name %d\n",
+						j, i);
+			tid[i] = j;
+		}
+	}
+	printf ("schedtest: Threads created\n");
+
+	printf ("sched_test: function=0x%08x\n", (unsigned)testthread);
+	for (i = 0; i < NUMTHREADS; i++) {
+		printf ("schedtest: Setting thread %d runnable\n", tid[i]);
+		thread_start (tid[i]);
+		thread_yield ();
+	}
+	printf ("schedtest: Started %d threads\n", NUMTHREADS);
+
+	while (1) {
+		printf ("schedtest: Waiting for threads to complete\n");
+		if (tstc () && getc () == 0x3) {
+			printf ("schedtest: Aborting threads...\n");
+			for (i = 0; i < NUMTHREADS; i++) {
+				printf ("schedtest: Deleting thread %d\n", tid[i]);
+				thread_delete (tid[i]);
+			}
+			return RC_SUCCESS;
+		}
+		j = -1;
+		i = thread_join (&j);
+		if (i == RC_FAILURE) {
+			printf ("schedtest: No threads pending, "
+						"exiting schedular test\n");
+			return RC_SUCCESS;
+		}
+		printf ("schedtest: thread is %d returned %d\n", i, j);
+		thread_yield ();
+	}
+
+	return RC_SUCCESS;
+}
+
+static int testthread (void *name)
+{
+	int i;
+
+	printf ("testthread: Begin executing thread, myname %d, &i=0x%08x\n",
+		*(int *) name, (unsigned)&i);
+
+	printf ("Thread %02d, i=%d\n", *(int *) name, i);
+
+	for (i = 0; i < 0xffff * (*(int *) name + 1); i++) {
+		if (tstc () && getc () == 0x3) {
+			printf ("testthread: myname %d terminating.\n",
+						*(int *) name);
+			return *(int *) name + 1;
+		}
+
+		if (i % 100 == 0)
+			thread_yield ();
+	}
+
+	printf ("testthread: returning %d, i=0x%x\n",
+				*(int *) name + 1, i);
+
+	return *(int *) name + 1;
+}
+
+
+static void sched_init (void)
+{
+	int i;
+
+	for (i = MASTER_THREAD + 1; i < MAX_THREADS; i++)
+		lthreads[i].state = STATE_EMPTY;
+
+	current_tid = MASTER_THREAD;
+	lthreads[current_tid].state = STATE_RUNNABLE;
+	PDEBUG ("sched_init: master context = 0x%08x",
+		(unsigned)lthreads[current_tid].context);
+	return;
+}
+
+static void thread_yield (void)
+{
+	static int i;
+
+	PDEBUG ("thread_yield: current tid=%d", current_tid);
+
+#define SWITCH(new)							\
+	if(lthreads[new].state == STATE_RUNNABLE) {			\
+		PDEBUG("thread_yield: %d match, ctx=0x%08x",		\
+			new,						\
+			(unsigned)lthreads[current_tid].context);	\
+		if(setjmp(lthreads[current_tid].context) == 0) {	\
+			current_tid = new;				\
+			PDEBUG("thread_yield: tid %d returns 0",	\
+				new);					\
+			longjmp(lthreads[new].context, 1);		\
+		} else {						\
+			PDEBUG("thread_yield: tid %d returns 1",	\
+				new);					\
+			return;						\
+		}							\
+	}
+
+	for (i = current_tid + 1; i < MAX_THREADS; i++) {
+		SWITCH (i);
+	}
+
+	if (current_tid != 0) {
+		for (i = 0; i <= current_tid; i++) {
+			SWITCH (i);
+		}
+	}
+
+	PDEBUG ("thread_yield: returning from thread_yield");
+	return;
+}
+
+static int thread_create (int (*func) (void *), void *arg)
+{
+	int i;
+
+	for (i = MASTER_THREAD + 1; i < MAX_THREADS; i++) {
+		if (lthreads[i].state == STATE_EMPTY) {
+			lthreads[i].state = STATE_STOPPED;
+			lthreads[i].func = func;
+			lthreads[i].arg = arg;
+			PDEBUG ("thread_create: returns new tid %d", i);
+			return i;
+		}
+	}
+
+	PDEBUG ("thread_create: returns failure");
+	return RC_FAILURE;
+}
+
+static int thread_delete (int id)
+{
+	if (id <= MASTER_THREAD || id > MAX_THREADS)
+		return RC_FAILURE;
+
+	if (current_tid == id)
+		return RC_FAILURE;
+
+	lthreads[id].state = STATE_EMPTY;
+	return RC_SUCCESS;
+}
+
+static void thread_launcher (void)
+{
+	PDEBUG ("thread_launcher: invoking func=0x%08x",
+		   (unsigned)lthreads[current_tid].func);
+
+	lthreads[current_tid].retval =
+			lthreads[current_tid].func (lthreads[current_tid].arg);
+
+	PDEBUG ("thread_launcher: tid %d terminated", current_tid);
+
+	lthreads[current_tid].state = STATE_TERMINATED;
+	thread_yield ();
+	printf ("thread_launcher: should NEVER get here!\n");
+
+	return;
+}
+
+static int thread_start (int id)
+{
+	PDEBUG ("thread_start: id=%d", id);
+	if (id <= MASTER_THREAD || id > MAX_THREADS) {
+		return RC_FAILURE;
+	}
+
+	if (lthreads[id].state != STATE_STOPPED)
+		return RC_FAILURE;
+
+	if (setjmp (lthreads[current_tid].context) == 0) {
+		lthreads[id].state = STATE_RUNNABLE;
+		current_tid = id;
+		PDEBUG ("thread_start: to be stack=0%08x",
+			(unsigned)lthreads[id].stack);
+		setctxsp ((vu_char *)&lthreads[id].stack[STK_SIZE]);
+		thread_launcher ();
+	}
+
+	PDEBUG ("thread_start: Thread id=%d started, parent returns", id);
+
+	return RC_SUCCESS;
+}
+
+#if 0	/* not used so far */
+static int thread_stop (int id)
+{
+	if (id <= MASTER_THREAD || id >= MAX_THREADS)
+		return RC_FAILURE;
+
+	if (current_tid == id)
+		return RC_FAILURE;
+
+	lthreads[id].state = STATE_STOPPED;
+	return RC_SUCCESS;
+}
+#endif	/* not used so far */
+
+static int thread_join (int *ret)
+{
+	int i, j = 0;
+
+	PDEBUG ("thread_join: *ret = %d", *ret);
+
+	if (!(*ret == -1 || *ret > MASTER_THREAD || *ret < MAX_THREADS)) {
+		PDEBUG ("thread_join: invalid tid %d", *ret);
+		return RC_FAILURE;
+	}
+
+	if (*ret == -1) {
+		PDEBUG ("Checking for tid = -1");
+		while (1) {
+			/* PDEBUG("thread_join: start while-loopn"); */
+			j = 0;
+			for (i = MASTER_THREAD + 1; i < MAX_THREADS; i++) {
+				if (lthreads[i].state == STATE_TERMINATED) {
+					*ret = lthreads[i].retval;
+					lthreads[i].state = STATE_EMPTY;
+					/* PDEBUG("thread_join: returning retval %d of tid %d",
+					   ret, i); */
+					return RC_SUCCESS;
+				}
+
+				if (lthreads[i].state != STATE_EMPTY) {
+					PDEBUG ("thread_join: %d used slots tid %d state=%d",
+						   j, i, lthreads[i].state);
+					j++;
+				}
+			}
+			if (j == 0) {
+				PDEBUG ("thread_join: all slots empty!");
+				return RC_FAILURE;
+			}
+			/*  PDEBUG("thread_join: yielding"); */
+			thread_yield ();
+			/*  PDEBUG("thread_join: back from yield"); */
+		}
+	}
+
+	if (lthreads[*ret].state == STATE_TERMINATED) {
+		i = *ret;
+		*ret = lthreads[*ret].retval;
+		lthreads[*ret].state = STATE_EMPTY;
+		PDEBUG ("thread_join: returing %d for tid %d", *ret, i);
+		return RC_SUCCESS;
+	}
+
+	PDEBUG ("thread_join: thread %d is not terminated!", *ret);
+	return RC_FAILURE;
+}