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at91sam9: add watchdog support

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Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
This commit is contained in:
Jean-Christophe PLAGNIOL-VILLARD 2009-03-27 23:26:42 +01:00
parent a47492ac60
commit 843a2654bc
6 changed files with 178 additions and 1 deletions
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1
Makefile
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@ -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

11
doc/README.at91
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@ -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.

4
drivers/serial/atmel_usart.c
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@ -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);
}

46
drivers/watchdog/Makefile Normal file
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@ -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
#########################################################################

79
drivers/watchdog/at91sam9_wdt.c Normal file
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@ -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));
}

38
include/asm-arm/arch-at91/at91_wdt.h Normal file
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@ -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