altos/lpc: Add boot loader

Support the USB boot loader, add USB pull-up support.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 67 insertions, 0 deletions

diff --git a/src/lpc/ao_boot_chain.c b/src/lpc/ao_boot_chain.c
new file mode 100644
index 00000000..a08d1f2c
--- /dev/null
+++ b/src/lpc/ao_boot_chain.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * 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; version 2 of the License.
+ *
+ * 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 <ao.h>
+#include <ao_boot.h>
+
+void
+ao_boot_chain(uint32_t *base)
+{
+	uint32_t	sp;
+	uint32_t	pc;
+
+	sp = base[0];
+	pc = base[1];
+	if (0x00000100 <= pc && pc <= 0x00008000 && (pc & 1) == 1) {
+		asm ("mov sp, %0" : : "r" (sp));
+		asm ("mov lr, %0" : : "r" (pc));
+		asm ("bx lr");
+	}
+}
+
+#define AO_BOOT_SIGNAL	0x5a5aa5a5
+#define AO_BOOT_CHECK	0xc3c33c3c
+
+struct ao_boot {
+	uint32_t	*base;
+	uint32_t	signal;
+	uint32_t	check;
+};
+
+static struct ao_boot __attribute__ ((section(".boot"))) ao_boot;
+	
+int
+ao_boot_check_chain(void)
+{
+	if (ao_boot.signal == AO_BOOT_SIGNAL && ao_boot.check == AO_BOOT_CHECK) {
+		ao_boot.signal = 0;
+		ao_boot.check = 0;
+		if (ao_boot.base == 0)
+			return 0;
+		ao_boot_chain(ao_boot.base);
+	}
+	return 1;
+}
+
+void
+ao_boot_reboot(uint32_t *base)
+{
+	ao_boot.base = base;
+	ao_boot.signal = AO_BOOT_SIGNAL;
+	ao_boot.check = AO_BOOT_CHECK;
+	ao_arch_reboot();
+}