at91sam9: add watchdog support
authorJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Fri, 27 Mar 2009 22:26:42 +0000 (23:26 +0100)
committerJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Sat, 4 Apr 2009 18:42:19 +0000 (20:42 +0200)
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Makefile
doc/README.at91
drivers/serial/atmel_usart.c
drivers/watchdog/Makefile [new file with mode: 0644]
drivers/watchdog/at91sam9_wdt.c [new file with mode: 0644]
include/asm-arm/arch-at91/at91_wdt.h [new file with mode: 0644]

index f9edd9db3925668445d026b9ed61fda01d7b278d..9f4e431e792acc39c1119bb45bf76a4e44cd877f 100644 (file)
--- 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
index e460e666237123eb0f7df7b21a0a4647ea7a0850..9b4eae6e143092d03296b949c5e4c330f0a3b57d 100644 (file)
@@ -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.
index f3b146c22d783ae2eb8b2bab77499c38dfc16850..f50552a2c70c7fade9799a132940371b8e449aa7 100644 (file)
@@ -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 (file)
index 0000000..200968d
--- /dev/null
@@ -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 (file)
index 0000000..5bb8b77
--- /dev/null
@@ -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 (file)
index 0000000..7e18537
--- /dev/null
@@ -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