at91sam9: add watchdog support

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

6 files changed, 178 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index f9edd9d..9f4e431 100644
--- a/Makefile
+++ b/Makefile
@@ -265,6 +265,7 @@ LIBS += drivers/serial/libserial.a
 LIBS += drivers/twserial/libtws.a
 LIBS += drivers/usb/libusb.a
 LIBS += drivers/video/libvideo.a
+LIBS += drivers/watchdog/libwatchdog.a
 LIBS += common/libcommon.a
 LIBS += libfdt/libfdt.a
 LIBS += api/libapi.a
diff --git a/doc/README.at91 b/doc/README.at91
index e460e66..9b4eae6 100644
--- a/doc/README.at91
+++ b/doc/README.at91
@@ -2,6 +2,7 @@ Atmel AT91 Evaluation kits
 
 http://atmel.com/dyn/products/tools.asp?family_id=605#1443
 
+I. Board mapping & boot media
 ------------------------------------------------------------------------------
 AT91SAM9260EK, AT91SAM9G20EK & AT91SAM9XEEK
 ------------------------------------------------------------------------------
@@ -86,3 +87,13 @@ Environment variables
 		make at91sam9263ek_config		- use data flash (spi cs0) (default)
 		make at91sam9263ek_nandflash_config	- use nand flash
 		make at91sam9263ek_dataflash_cs0_config	- use data flash (spi cs0)
+
+II. Watchdog support
+
+	For security reasons, the at91 watchdog is running at boot time and,
+	if deactivated, cannot be used anymore.
+	If you want to use the watchdog, you will need to keep it running in
+	your code (make sure not to disable it in AT91Bootstrap for instance).
+
+	In the U-Boot configuration, the AT91 watchdog support is enabled using
+	the CONFIG_AT91SAM9_WATCHDOG and CONFIG_HW_WATCHDOG options.
diff --git a/drivers/serial/atmel_usart.c b/drivers/serial/atmel_usart.c
index f3b146c..f50552a 100644
--- a/drivers/serial/atmel_usart.c
+++ b/drivers/serial/atmel_usart.c
@@ -16,6 +16,7 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 #include <common.h>
+#include <watchdog.h>
 
 #include <asm/io.h>
 #include <asm/arch/clk.h>
@@ -87,7 +88,8 @@ void serial_puts(const char *s)
 
 int serial_getc(void)
 {
-	while (!(usart3_readl(CSR) & USART3_BIT(RXRDY))) ;
+	while (!(usart3_readl(CSR) & USART3_BIT(RXRDY)))
+		 WATCHDOG_RESET();
 	return usart3_readl(RHR);
 }
 
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
new file mode 100644
index 0000000..200968d
--- /dev/null
+++ b/drivers/watchdog/Makefile
@@ -0,0 +1,46 @@
+#
+# (C) Copyright 2008
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# 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 $(TOPDIR)/config.mk
+
+LIB	:= $(obj)libwatchdog.a
+
+COBJS-$(CONFIG_AT91SAM9_WATCHDOG) += at91sam9_wdt.o
+
+COBJS	:= $(COBJS-y)
+SRCS	:= $(COBJS:.o=.c)
+OBJS	:= $(addprefix $(obj),$(COBJS))
+
+all:	$(LIB)
+
+$(LIB):	$(obj).depend $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+
+#########################################################################
+
+# defines $(obj).depend target
+include $(SRCTREE)/rules.mk
+
+sinclude $(obj).depend
+
+#########################################################################
diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c
new file mode 100644
index 0000000..5bb8b77
--- /dev/null
+++ b/drivers/watchdog/at91sam9_wdt.c
@@ -0,0 +1,79 @@
+/*
+ * [origin: Linux kernel drivers/watchdog/at91sam9_wdt.c]
+ *
+ * Watchdog driver for Atmel AT91SAM9x processors.
+ *
+ * Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ * Copyright (C) 2008 Renaud CERRATO r.cerrato@til-technologies.fr
+ *
+ * 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.
+ */
+
+/*
+ * The Watchdog Timer Mode Register can be only written to once. If the
+ * timeout need to be set from U-Boot, be sure that the bootstrap doesn't
+ * write to this register. Inform Linux to it too
+ */
+
+#include <common.h>
+#include <watchdog.h>
+#include <asm/arch/hardware.h>
+#include <asm/arch/io.h>
+#include <asm/arch/at91_wdt.h>
+
+/*
+ * AT91SAM9 watchdog runs a 12bit counter @ 256Hz,
+ * use this to convert a watchdog
+ * value from/to milliseconds.
+ */
+#define ms_to_ticks(t)	(((t << 8) / 1000) - 1)
+#define ticks_to_ms(t)	(((t + 1) * 1000) >> 8)
+
+/* Hardware timeout in seconds */
+#define WDT_HW_TIMEOUT 2
+
+/*
+ * Set the watchdog time interval in 1/256Hz (write-once)
+ * Counter is 12 bit.
+ */
+static int at91_wdt_settimeout(unsigned int timeout)
+{
+	unsigned int reg;
+	unsigned int mr;
+
+	/* Check if disabled */
+	mr = at91_sys_read(AT91_WDT_MR);
+	if (mr & AT91_WDT_WDDIS) {
+		printf("sorry, watchdog is disabled\n");
+		return -1;
+	}
+
+	/*
+	 * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
+	 *
+	 * Since WDV is a 12-bit counter, the maximum period is
+	 * 4096 / 256 = 16 seconds.
+	 */
+	reg = AT91_WDT_WDRSTEN	/* causes watchdog reset */
+		/* | AT91_WDT_WDRPROC	causes processor reset only */
+		| AT91_WDT_WDDBGHLT		/* disabled in debug mode */
+		| AT91_WDT_WDD			/* restart at any time */
+		| (timeout & AT91_WDT_WDV);	/* timer value */
+	at91_sys_write(AT91_WDT_MR, reg);
+
+	return 0;
+}
+
+void hw_watchdog_reset(void)
+{
+	at91_sys_write(AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
+}
+
+void hw_watchdog_init(void)
+{
+	/* 16 seconds timer, resets enabled */
+	at91_wdt_settimeout(ms_to_ticks(WDT_HW_TIMEOUT * 1000));
+}
diff --git a/include/asm-arm/arch-at91/at91_wdt.h b/include/asm-arm/arch-at91/at91_wdt.h
new file mode 100644
index 0000000..7e18537
--- /dev/null
+++ b/include/asm-arm/arch-at91/at91_wdt.h
@@ -0,0 +1,38 @@
+/*
+ * [origin: Linux kernel arch/arm/mach-at91/include/mach/at91_wdt.h]
+ *
+ * Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ * Copyright (C) 2007 Andrew Victor
+ * Copyright (C) 2007 Atmel Corporation.
+ *
+ * Watchdog Timer (WDT) - System peripherals regsters.
+ * Based on AT91SAM9261 datasheet revision D.
+ *
+ * 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.
+ */
+
+#ifndef AT91_WDT_H
+#define AT91_WDT_H
+
+#define AT91_WDT_CR		(AT91_WDT + 0x00)	/* Watchdog Control Register */
+#define		AT91_WDT_WDRSTT		(1    << 0)		/* Restart */
+#define		AT91_WDT_KEY		(0xa5 << 24)		/* KEY Password */
+
+#define AT91_WDT_MR		(AT91_WDT + 0x04)	/* Watchdog Mode Register */
+#define		AT91_WDT_WDV		(0xfff << 0)		/* Counter Value */
+#define		AT91_WDT_WDFIEN		(1     << 12)		/* Fault Interrupt Enable */
+#define		AT91_WDT_WDRSTEN	(1     << 13)		/* Reset Processor */
+#define		AT91_WDT_WDRPROC	(1     << 14)		/* Timer Restart */
+#define		AT91_WDT_WDDIS		(1     << 15)		/* Watchdog Disable */
+#define		AT91_WDT_WDD		(0xfff << 16)		/* Delta Value */
+#define		AT91_WDT_WDDBGHLT	(1     << 28)		/* Debug Halt */
+#define		AT91_WDT_WDIDLEHLT	(1     << 29)		/* Idle Halt */
+
+#define AT91_WDT_SR		(AT91_WDT + 0x08)	/* Watchdog Status Register */
+#define		AT91_WDT_WDUNF		(1 << 0)		/* Watchdog Underflow */
+#define		AT91_WDT_WDERR		(1 << 1)		/* Watchdog Error */
+
+#endif