altos: Clean up boot loader support

Split out code into separate files.
Add support for getting back to boot loader from application.

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

12 files changed, 172 insertions, 65 deletions

diff --git a/src/stm-demo/Makefile b/src/stm-demo/Makefile
index ab12f47b..e6cd55e4 100644
--- a/src/stm-demo/Makefile
+++ b/src/stm-demo/Makefile
@@ -17,6 +17,7 @@ INC = \
 #
 ALTOS_SRC = \
 	ao_interrupt.c \
+	ao_boot_chain.c \
 	ao_product.c \
 	ao_romconfig.c \
 	ao_cmd.c \
diff --git a/src/stm-demo/ao_demo.c b/src/stm-demo/ao_demo.c
index b82cb735..d4645281 100644
--- a/src/stm-demo/ao_demo.c
+++ b/src/stm-demo/ao_demo.c
@@ -20,6 +20,7 @@
 #include <ao_event.h>
 #include <ao_quadrature.h>
 #include <ao_button.h>
+#include <ao_boot.h>
 
 struct ao_task demo_task;
 
@@ -168,6 +169,13 @@ ao_event(void)
 
 }
 
+static void
+ao_boot_loader(void)
+{
+	flush();
+	ao_boot_reboot((uint32_t *) 0);
+}
+
 __code struct ao_cmds ao_demo_cmds[] = {
 	{ ao_dma_test,	"D\0DMA test" },
 	{ ao_spi_write, "W\0SPI write" },
@@ -175,6 +183,7 @@ __code struct ao_cmds ao_demo_cmds[] = {
 	{ ao_i2c_write, "i\0I2C write" },
 	{ ao_temp, "t\0Show temp" },
 	{ ao_event, "e\0Monitor event queue" },
+	{ ao_boot_loader, "L\0Reboot to boot loader" },
 	{ 0, NULL }
 };
 
diff --git a/src/stm-demo/ao_pins.h b/src/stm-demo/ao_pins.h
index 07b4a19d..40e48a36 100644
--- a/src/stm-demo/ao_pins.h
+++ b/src/stm-demo/ao_pins.h
@@ -68,6 +68,8 @@
 #define HAS_BEEP		0
 #define PACKET_HAS_SLAVE	0
 
+#define AO_BOOT_CHAIN		1
+
 #define LOW_LEVEL_DEBUG		1
 
 #define LED_PORT_ENABLE		STM_RCC_AHBENR_GPIOBEN
diff --git a/src/stm-flash/Makefile b/src/stm-flash/Makefile
index 3c7b4966..e4a2f321 100644
--- a/src/stm-flash/Makefile
+++ b/src/stm-flash/Makefile
@@ -17,6 +17,8 @@ INC = \
 #
 ALTOS_SRC = \
 	ao_interrupt.c \
+	ao_boot_chain.c \
+	ao_boot_pin.c \
 	ao_product.c \
 	ao_romconfig.c \
 	ao_task.c \
diff --git a/src/stm-flash/ao_pins.h b/src/stm-flash/ao_pins.h
index ca53d844..382ef353 100644
--- a/src/stm-flash/ao_pins.h
+++ b/src/stm-flash/ao_pins.h
@@ -65,10 +65,13 @@
 #define HAS_TASK_INFO		0
 #define HAS_VERSION		0
 
+#define AO_BOOT_CHAIN		1
+#define AO_BOOT_PIN		1
+
 #define AO_BOOT_APPLICATION_GPIO	stm_gpioa
 #define AO_BOOT_APPLICATION_PIN		0
 #define AO_BOOT_APPLICATION_VALUE	1
 #define AO_BOOT_APPLICATION_MODE	0
-#define AO_BOOT_APPLICATION_BASE	0x2000
+#define AO_BOOT_APPLICATION_BASE	((uint32_t *) 0x2000)
 
 #endif /* _AO_PINS_H_ */
diff --git a/src/stm-flash/ao_stm_flash.c b/src/stm-flash/ao_stm_flash.c
index 16dd1189..968da9f1 100644
--- a/src/stm-flash/ao_stm_flash.c
+++ b/src/stm-flash/ao_stm_flash.c
@@ -25,8 +25,14 @@ ao_panic(uint8_t reason)
 	for (;;);
 }
 
+void
+ao_application(void)
+{
+	ao_boot_reboot(AO_BOOT_APPLICATION_BASE);
+}
+
 __code struct ao_cmds ao_flash_cmds[] = {
-	{ ao_reboot_application, "A\0Switch to application" },
+	{ ao_application, "A\0Switch to application" },
 	{ 0, NULL },
 };
 
diff --git a/src/stm/altos-application.ld b/src/stm/altos-application.ld
index 63a3be00..5110da84 100644
--- a/src/stm/altos-application.ld
+++ b/src/stm/altos-application.ld
@@ -48,16 +48,27 @@ SECTIONS {
 		__text_end__ = .;
 	} > rom
 
+	/* Boot data which must live at the start of ram so that
+	 * the application and bootloader share the same addresses.
+	 * This must be all uninitialized data
+	 */
+	.boot : {
+		__boot_start__ = .;
+		*(.boot)
+		. = ALIGN(4);
+		__boot_end__ = .;
+	} >ram
+
 	/* Data -- relocated to RAM, but written to ROM
 	 */
-	.data ORIGIN(ram) : AT (ADDR(.ARM.exidx) + SIZEOF (.ARM.exidx)) {
+	.data : {
 		__data_start__ = .;
 		*(.data)	/* initialized data */
 		__data_end__ = .;
-		__bss_start__ = .;
-	} >ram
+	} >ram AT>rom
 
 	.bss : {
+		__bss_start__ = .;
 		*(.bss)
 		*(COMMON)
 		__bss_end__ = .;
diff --git a/src/stm/altos-loader.ld b/src/stm/altos-loader.ld
index 50a425c7..2e36dce9 100644
--- a/src/stm/altos-loader.ld
+++ b/src/stm/altos-loader.ld
@@ -48,9 +48,20 @@ SECTIONS {
 	} > rom
 	__text_end__ = .;
 
+	/* Boot data which must live at the start of ram so that
+	 * the application and bootloader share the same addresses.
+	 * This must be all uninitialized data
+	 */
+	.boot : {
+		__boot_start__ = .;
+		*(.boot)
+		. = ALIGN(4);
+		__boot_end__ = .;
+	} >ram
+
 	/* Functions placed in RAM (required for flashing) */
 	.textram : {
-		__text_ram_start = .;
+		__text_ram_start__ = .;
 		__data_start__ = .;
 		*(.text.ram)
 		. = ALIGN(4);
diff --git a/src/stm/ao_boot.h b/src/stm/ao_boot.h
index 863d8e05..3e8c50ba 100644
--- a/src/stm/ao_boot.h
+++ b/src/stm/ao_boot.h
@@ -19,6 +19,15 @@
 #define _AO_BOOT_H_
 
 void
-ao_reboot_application(void);
+ao_boot_chain(uint32_t *base);
+
+void
+ao_boot_check_pin(void);
+
+void
+ao_boot_check_chain(void);
+
+void
+ao_boot_reboot(uint32_t *base);
 
 #endif /* _AO_BOOT_H_ */
diff --git a/src/stm/ao_boot_chain.c b/src/stm/ao_boot_chain.c
new file mode 100644
index 00000000..9c63272b
--- /dev/null
+++ b/src/stm/ao_boot_chain.c
@@ -0,0 +1,62 @@
+/*
+ * 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];
+	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;
+	
+void
+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;
+		ao_boot_chain(ao_boot.base);
+	}
+}
+
+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();
+}
diff --git a/src/stm/ao_boot_pin.c b/src/stm/ao_boot_pin.c
new file mode 100644
index 00000000..03b0214f
--- /dev/null
+++ b/src/stm/ao_boot_pin.c
@@ -0,0 +1,43 @@
+/*
+ * 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>
+#include <ao_exti.h>
+
+void
+ao_boot_check_pin(void)
+{
+	uint16_t v;
+
+	/* Enable power interface clock */
+	stm_rcc.apb1enr |= (1 << STM_RCC_APB1ENR_PWREN);
+	
+	/* Enable the input pin */
+	ao_enable_input(&AO_BOOT_APPLICATION_GPIO, AO_BOOT_APPLICATION_PIN,
+			AO_BOOT_APPLICATION_MODE);
+
+	/* Read the value */
+	v = stm_gpio_get(&AO_BOOT_APPLICATION_GPIO, AO_BOOT_APPLICATION_PIN);
+
+	/* Reset the chip to turn off the port and the power interface clock */
+	ao_gpio_set_mode(&AO_BOOT_APPLICATION_GPIO, AO_BOOT_APPLICATION_PIN, 0);
+	ao_disable_port(&AO_BOOT_APPLICATION_GPIO);
+	stm_rcc.apb1enr &= ~(1 << STM_RCC_APB1ENR_PWREN);
+	if (v == AO_BOOT_APPLICATION_VALUE)
+		ao_boot_chain(AO_BOOT_APPLICATION_BASE);
+}
diff --git a/src/stm/ao_interrupt.c b/src/stm/ao_interrupt.c
index 9e756219..49156285 100644
--- a/src/stm/ao_interrupt.c
+++ b/src/stm/ao_interrupt.c
@@ -18,6 +18,7 @@
 #include <ao.h>
 #include "stm32l.h"
 #include <string.h>
+#include <ao_boot.h>
 
 extern void main(void);
 extern char __stack__;
@@ -38,67 +39,14 @@ void stm_ignore_isr(void)
 
 const void *stm_interrupt_vector[];
 
-#define BOOT_FETCH(o)	(*((uint32_t *) (AO_BOOT_APPLICATION_BASE + (o))))
-
-#ifdef AO_BOOT_APPLICATION_PIN
-#include <ao_exti.h>
-
-#define AO_BOOT_APPLICATION		0x5a5aa5a5
-#define AO_BOOT_APPLICATION_CHECK	0xc3c33c3c
-
-static uint32_t	ao_boot_application;
-static uint32_t	ao_boot_application_check;
-
-static void
-ao_boot_chain(void) {
-	uint32_t	sp;
-	uint32_t	pc;
-
-	sp = BOOT_FETCH(0);
-	pc = BOOT_FETCH(4);
-	asm ("mov sp, %0" : : "r" (sp));
-	asm ("mov lr, %0" : : "r" (pc));
-	asm ("bx lr");
-}
-
-void
-ao_reboot_application(void)
+void start(void)
 {
-	ao_boot_application = AO_BOOT_APPLICATION;
-	ao_boot_application_check = AO_BOOT_APPLICATION_CHECK;
-	ao_arch_reboot();
-}
-
+#ifdef AO_BOOT_CHAIN
+	ao_boot_check_chain();
 #endif
-
-void start(void) {
-#ifdef AO_BOOT_APPLICATION_PIN
-	uint16_t v;
-
-	if (ao_boot_application == AO_BOOT_APPLICATION &&
-	    ao_boot_application_check == AO_BOOT_APPLICATION_CHECK) {
-		ao_boot_application = 0;
-		ao_boot_application_check = 0;
-		ao_boot_chain();
-	}
-	/* Enable power interface clock */
-	stm_rcc.apb1enr |= (1 << STM_RCC_APB1ENR_PWREN);
-	
-	/* Enable the input pin */
-	ao_enable_input(&AO_BOOT_APPLICATION_GPIO, AO_BOOT_APPLICATION_PIN,
-			AO_BOOT_APPLICATION_MODE);
-
-	/* Read the value */
-	v = stm_gpio_get(&AO_BOOT_APPLICATION_GPIO, AO_BOOT_APPLICATION_PIN);
-
-	/* Reset the chip to turn off the port and the power interface clock */
-	ao_gpio_set_mode(&AO_BOOT_APPLICATION_GPIO, AO_BOOT_APPLICATION_PIN, 0);
-	ao_disable_port(&AO_BOOT_APPLICATION_GPIO);
-	stm_rcc.apb1enr &= ~(1 << STM_RCC_APB1ENR_PWREN);
-	if (v == AO_BOOT_APPLICATION_VALUE)
-		ao_boot_chain();
+#ifdef AO_BOOT_PIN
+	ao_boot_check_pin();
 #endif
-
 	/* Set interrupt vector table offset */
 	stm_nvic.vto = (uint32_t) &stm_interrupt_vector;
 	memcpy(&__data_start__, &__text_end__, &__data_end__ - &__data_start__);