[U-Boot] [PATCH 02/13 V2] at91sam9: add watchdog support
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Fri Mar 27 23:30:15 CET 2009
Signed-off-by: Nicolas Ferre <nicolas.ferre at atmel.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
---
update the readme
Best Regards,
J.
Makefile | 1 +
doc/README.at91 | 11 +++++
drivers/serial/atmel_usart.c | 4 +-
drivers/watchdog/Makefile | 46 ++++++++++++++++++++
drivers/watchdog/at91sam9_wdt.c | 79 ++++++++++++++++++++++++++++++++++
include/asm-arm/arch-at91/at91_wdt.h | 38 ++++++++++++++++
6 files changed, 178 insertions(+), 1 deletions(-)
create mode 100644 drivers/watchdog/Makefile
create mode 100644 drivers/watchdog/at91sam9_wdt.c
create mode 100644 include/asm-arm/arch-at91/at91_wdt.h
diff --git a/Makefile b/Makefile
index 1cce381..d774e2e 100644
--- a/Makefile
+++ b/Makefile
@@ -264,6 +264,7 @@ LIBS += drivers/rtc/librtc.a
LIBS += drivers/serial/libserial.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 at 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 at jcrosoft.com>
+ * Copyright (C) 2008 Renaud CERRATO r.cerrato at 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 at 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
--
1.6.2.1
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