[U-Boot] [PATCH] bcm2835: wdt: support for the bcm2835/2836 wdt

[U-Boot] [PATCH] bcm2835: wdt: support for the bcm2835/2836 wdt

[Paolo Pisati]

The following patch add support for the watchdog built into the
bcm2835/2836 chips, using the max timeout (~15s).

By default the watchdog is compiled in, but disabled.
To enable it, apply the following patch:

--- a/include/configs/rpi.h
+++ b/include/configs/rpi.h
@@ -109,6 +109,7 @@
 
 /* Watchdog support */
 #define CONFIG_BCM2835_WDT
+#define CONFIG_HW_WATCHDOG
 
 /* Console configuration */
 #define CONFIG_SYS_CBSIZE              1024
-- 
2.7.4

Tested on my RaspberryPi2.

Paolo Pisati (1):
  bcm2835_wdt: support for the BCM2835/2836 watchdog

 arch/arm/mach-bcm283x/reset.c  | 21 ++++++++++++++++++---
 board/raspberrypi/rpi/rpi.c    |  4 ++++
 drivers/watchdog/Makefile      |  1 +
 drivers/watchdog/bcm2835_wdt.c | 34 ++++++++++++++++++++++++++++++++++
 include/configs/rpi.h          |  3 +++
 scripts/config_whitelist.txt   |  1 +
 6 files changed, 61 insertions(+), 3 deletions(-)
 create mode 100644 drivers/watchdog/bcm2835_wdt.c

-- 
2.7.4

[U-Boot] [PATCH] bcm2835_wdt: support for the BCM2835/2836 watchdog

[Paolo Pisati]

Signed-off-by: Paolo Pisati <p.pisati@gmail.com>
---
 arch/arm/mach-bcm283x/reset.c  | 21 ++++++++++++++++++---
 board/raspberrypi/rpi/rpi.c    |  4 ++++
 drivers/watchdog/Makefile      |  1 +
 drivers/watchdog/bcm2835_wdt.c | 34 ++++++++++++++++++++++++++++++++++
 include/configs/rpi.h          |  3 +++
 scripts/config_whitelist.txt   |  1 +
 6 files changed, 61 insertions(+), 3 deletions(-)
 create mode 100644 drivers/watchdog/bcm2835_wdt.c

diff --git a/arch/arm/mach-bcm283x/reset.c b/arch/arm/mach-bcm283x/reset.c
index 685815c..b62cb8a 100644
--- a/arch/arm/mach-bcm283x/reset.c
+++ b/arch/arm/mach-bcm283x/reset.c
@@ -21,18 +21,33 @@
  */
 #define BCM2835_WDOG_RSTS_RASPBERRYPI_HALT	0x555
 
+/* max ticks timeout */
+#define BCM2835_WDOG_MAX_TIMEOUT	0x000fffff
+
+#ifdef CONFIG_BCM2835_WDT
+extern void hw_watchdog_disable(void);
+#else
+void hw_watchdog_disable(void) {}
+#endif
+
 __efi_runtime_data struct bcm2835_wdog_regs *wdog_regs =
 	(struct bcm2835_wdog_regs *)BCM2835_WDOG_PHYSADDR;
 
-void __efi_runtime reset_cpu(ulong addr)
+void __efi_runtime reset_cpu(ulong ticks)
 {
-	uint32_t rstc;
+	uint32_t rstc, timeout;
+
+	if (ticks == 0) {
+		hw_watchdog_disable();
+		timeout = RESET_TIMEOUT;
+	} else
+		timeout = ticks & BCM2835_WDOG_MAX_TIMEOUT;
 
 	rstc = readl(&wdog_regs->rstc);
 	rstc &= ~BCM2835_WDOG_RSTC_WRCFG_MASK;
 	rstc |= BCM2835_WDOG_RSTC_WRCFG_FULL_RESET;
 
-	writel(BCM2835_WDOG_PASSWORD | RESET_TIMEOUT, &wdog_regs->wdog);
+	writel(BCM2835_WDOG_PASSWORD | timeout, &wdog_regs->wdog);
 	writel(BCM2835_WDOG_PASSWORD | rstc, &wdog_regs->rstc);
 }
 
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
index 22e87a2..106e518 100644
--- a/board/raspberrypi/rpi/rpi.c
+++ b/board/raspberrypi/rpi/rpi.c
@@ -22,6 +22,7 @@
 #ifdef CONFIG_ARM64
 #include <asm/armv8/mmu.h>
 #endif
+#include <watchdog.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -478,6 +479,9 @@ static void rpi_disable_inactive_uart(void)
 
 int board_init(void)
 {
+#ifdef CONFIG_HW_WATCHDOG
+	hw_watchdog_init();
+#endif
 #ifndef CONFIG_PL01X_SERIAL
 	rpi_disable_inactive_uart();
 #endif
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index a007ae8..3b328ec 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_XILINX_TB_WATCHDOG) += xilinx_tb_wdt.o
 obj-$(CONFIG_BFIN_WATCHDOG)  += bfin_wdt.o
 obj-$(CONFIG_OMAP_WATCHDOG) += omap_wdt.o
 obj-$(CONFIG_DESIGNWARE_WATCHDOG) += designware_wdt.o
+obj-$(CONFIG_BCM2835_WDT)       += bcm2835_wdt.o
diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c
new file mode 100644
index 0000000..c76b164
--- /dev/null
+++ b/drivers/watchdog/bcm2835_wdt.c
@@ -0,0 +1,34 @@
+/*
+ * Watchdog driver for Broadcom BCM2835
+ *
+ * Copyright (C) 2017 Paolo Pisati <p.pisati@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/wdog.h>
+
+#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
+#define MAX_TIMEOUT   0xf /* ~15s */
+
+bool enabled = true;
+
+extern void reset_cpu(ulong ticks);
+
+void hw_watchdog_reset(void)
+{
+	if (enabled)
+		reset_cpu(SECS_TO_WDOG_TICKS(MAX_TIMEOUT));
+}
+
+void hw_watchdog_init(void)
+{
+	hw_watchdog_reset();
+}
+
+void hw_watchdog_disable(void)
+{
+	enabled = false;
+}
diff --git a/include/configs/rpi.h b/include/configs/rpi.h
index 45d8824..c34c84b 100644
--- a/include/configs/rpi.h
+++ b/include/configs/rpi.h
@@ -107,6 +107,9 @@
 #define CONFIG_CONS_INDEX		0
 #define CONFIG_BAUDRATE			115200
 
+/* Watchdog support */
+#define CONFIG_BCM2835_WDT
+
 /* Console configuration */
 #define CONFIG_SYS_CBSIZE		1024
 #define CONFIG_SYS_PBSIZE		(CONFIG_SYS_CBSIZE +		\
diff --git a/scripts/config_whitelist.txt b/scripts/config_whitelist.txt
index 00ee3f1..eb6cb8a 100644
--- a/scripts/config_whitelist.txt
+++ b/scripts/config_whitelist.txt
@@ -294,6 +294,7 @@ CONFIG_BCH_CONST_M
 CONFIG_BCH_CONST_PARAMS
 CONFIG_BCH_CONST_T
 CONFIG_BCM2835_GPIO
+CONFIG_BCM2835_WDT
 CONFIG_BCM283X_MU_SERIAL
 CONFIG_BCM_SF2_ETH
 CONFIG_BCM_SF2_ETH_DEFAULT_PORT
-- 
2.7.4

[U-Boot] [PATCH] bcm2835_wdt: support for the BCM2835/2836 watchdog

[Brüns, Stefan]

On Freitag, 27. Januar 2017 10:59:05 CET Paolo Pisati wrote:
> Signed-off-by: Paolo Pisati <p.pisati@gmail.com>
> ---
>  arch/arm/mach-bcm283x/reset.c  | 21 ++++++++++++++++++---
>  board/raspberrypi/rpi/rpi.c    |  4 ++++
>  drivers/watchdog/Makefile      |  1 +
>  drivers/watchdog/bcm2835_wdt.c | 34 ++++++++++++++++++++++++++++++++++
>  include/configs/rpi.h          |  3 +++
>  scripts/config_whitelist.txt   |  1 +
>  6 files changed, 61 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/watchdog/bcm2835_wdt.c
> 
> diff --git a/arch/arm/mach-bcm283x/reset.c b/arch/arm/mach-bcm283x/reset.c
> index 685815c..b62cb8a 100644
> --- a/arch/arm/mach-bcm283x/reset.c
> +++ b/arch/arm/mach-bcm283x/reset.c
> @@ -21,18 +21,33 @@
>   */
>  #define BCM2835_WDOG_RSTS_RASPBERRYPI_HALT	0x555
> 
> +/* max ticks timeout */
> +#define BCM2835_WDOG_MAX_TIMEOUT	0x000fffff
> +
> +#ifdef CONFIG_BCM2835_WDT
> +extern void hw_watchdog_disable(void);
> +#else
> +void hw_watchdog_disable(void) {}
> +#endif
> +
>  __efi_runtime_data struct bcm2835_wdog_regs *wdog_regs =
>  	(struct bcm2835_wdog_regs *)BCM2835_WDOG_PHYSADDR;
> 
> -void __efi_runtime reset_cpu(ulong addr)
> +void __efi_runtime reset_cpu(ulong ticks)
>  {
> -	uint32_t rstc;
> +	uint32_t rstc, timeout;
> +
> +	if (ticks == 0) {
> +		hw_watchdog_disable();
> +		timeout = RESET_TIMEOUT;

This is wrong. The efi runtime reset function calls this as reset_cpu(0), and 
then tries to call hw_watchdog_disable, which is not marked as __efi_runtime.

Actually, I can see no reason the watchdog setup piggybacks on the reset_cpu 
funtion.

> +	} else
> +		timeout = ticks & BCM2835_WDOG_MAX_TIMEOUT;
> 
>  	rstc = readl(&wdog_regs->rstc);
>  	rstc &= ~BCM2835_WDOG_RSTC_WRCFG_MASK;
>  	rstc |= BCM2835_WDOG_RSTC_WRCFG_FULL_RESET;
> 
> -	writel(BCM2835_WDOG_PASSWORD | RESET_TIMEOUT, &wdog_regs->wdog);
> +	writel(BCM2835_WDOG_PASSWORD | timeout, &wdog_regs->wdog);
>  	writel(BCM2835_WDOG_PASSWORD | rstc, &wdog_regs->rstc);
>  }
> 
> diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
> index 22e87a2..106e518 100644
> --- a/board/raspberrypi/rpi/rpi.c
> +++ b/board/raspberrypi/rpi/rpi.c
[...]
> --- a/scripts/config_whitelist.txt
> +++ b/scripts/config_whitelist.txt
> @@ -294,6 +294,7 @@ CONFIG_BCH_CONST_M
>  CONFIG_BCH_CONST_PARAMS
>  CONFIG_BCH_CONST_T
>  CONFIG_BCM2835_GPIO
> +CONFIG_BCM2835_WDT
>  CONFIG_BCM283X_MU_SERIAL
>  CONFIG_BCM_SF2_ETH
>  CONFIG_BCM_SF2_ETH_DEFAULT_PORT

I think the rule is no new CONFIG_xxx options, but appropriate options in 
KConfig.

Kind regards,

Stefan

[U-Boot] [PATCH] bcm2835_wdt: support for the BCM2835/2836 watchdog

[Paolo Pisati]

On Fri, Jan 27, 2017 at 04:20:10PM +0000, Br?ns, Stefan wrote:
> > ...
> > +
> >  __efi_runtime_data struct bcm2835_wdog_regs *wdog_regs =
> >  	(struct bcm2835_wdog_regs *)BCM2835_WDOG_PHYSADDR;
> > 
> > -void __efi_runtime reset_cpu(ulong addr)
> > +void __efi_runtime reset_cpu(ulong ticks)
> >  {
> > -	uint32_t rstc;
> > +	uint32_t rstc, timeout;
> > +
> > +	if (ticks == 0) {
> > +		hw_watchdog_disable();
> > +		timeout = RESET_TIMEOUT;
> 
> This is wrong. The efi runtime reset function calls this as reset_cpu(0), and 
> then tries to call hw_watchdog_disable, which is not marked as __efi_runtime.

Ok.
 
> Actually, I can see no reason the watchdog setup piggybacks on the reset_cpu 
> funtion.

Because there's a window after reset_cpu() is called but before real reset happens,
and if hw_watchdog_reset() is called in between, it breaks the reset procedure.

There must be a mechanism for reset_cpu() to disable the watchdog driver so it
won't interfere.

> 
> I think the rule is no new CONFIG_xxx options, but appropriate options in 
> KConfig.

I'll send a V2.
-- 
bye,
p.

[U-Boot] [PATCH] bcm2835: wdt: support for the bcm2835/2836 wdt

[Paolo Pisati]

[resend with swarren in cc:]

The following patch add support for the watchdog built into the
bcm2835/2836 chips, using the max timeout (~15s).

By default the watchdog is compiled in, but disabled.
To enable it, apply the following patch:

--- a/include/configs/rpi.h
+++ b/include/configs/rpi.h
@@ -109,6 +109,7 @@

 /* Watchdog support */
 #define CONFIG_BCM2835_WDT
+#define CONFIG_HW_WATCHDOG

 /* Console configuration */
 #define CONFIG_SYS_CBSIZE              1024
--
2.7.4

Tested on my RaspberryPi2.

Paolo Pisati (1):
  bcm2835_wdt: support for the BCM2835/2836 watchdog

 arch/arm/mach-bcm283x/reset.c  | 21 ++++++++++++++++++---
 board/raspberrypi/rpi/rpi.c    |  4 ++++
 drivers/watchdog/Makefile      |  1 +
 drivers/watchdog/bcm2835_wdt.c | 34 ++++++++++++++++++++++++++++++++++
 include/configs/rpi.h          |  3 +++
 scripts/config_whitelist.txt   |  1 +
 6 files changed, 61 insertions(+), 3 deletions(-)
 create mode 100644 drivers/watchdog/bcm2835_wdt.c

-- 
2.7.4