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Message-Id: <1184580334.11988.0.camel@roc-desktop>
Date: Mon, 16 Jul 2007 18:05:34 +0800
From: Bryan Wu <bryan.wu@...log.com>
To: bryan.wu@...log.com
Cc: Wim Van Sebroeck <wim@...ana.be>,
LKML <linux-kernel@...r.kernel.org>,
Mike Frysinger <michael.frysinger@...log.com>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 2/3] Blackfin on-chip watchdog driver
Hi Wim:
Could you please give some comments on this patch?
Thanks
- Bryan Wu
On Sun, 2007-07-15 at 02:50 +0800, Bryan Wu wrote:
> This patch implements the driver necessary use the Analog Devices
> Blackfin processor's on-chip watchdog controller, supports
> BF53[123]/BF53[467]/BF54[2489]/BF561.
>
> Signed-off-by: Mike Frysinger <michael.frysinger@...log.com>
> Signed-off-by: Bryan Wu <bryan.wu@...log.com>
> Cc: Wim Van Sebroeck <wim@...ana.be>
> ---
> MAINTAINERS | 8 +
> drivers/char/watchdog/Kconfig | 13 +
> drivers/char/watchdog/Makefile | 3 +
> drivers/char/watchdog/bfin_wdt.c | 490
> ++++++++++++++++++++++++++++++++++++++
> 4 files changed, 514 insertions(+), 0 deletions(-)
> create mode 100644 drivers/char/watchdog/bfin_wdt.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 21a2265..9ff42bd 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -776,6 +776,14 @@ L: uclinux-dist-devel@...ckfin.uclinux.org
> (subscribers-only)
> W: http://blackfin.uclinux.org
> S: Supported
>
> +BLACKFIN WATCHDOG DRIVER
> +P: Mike Frysinger
> +M: michael.frysinger@...log.com
> +M: vapier.adi@...il.com
> +L: uclinux-dist-devel@...ckfin.uclinux.org (subscribers-only)
> +W: http://blackfin.uclinux.org
> +S: Supported
> +
> BAYCOM/HDLCDRV DRIVERS FOR AX.25
> P: Thomas Sailer
> M: t.sailer@...mni.ethz.ch
> diff --git a/drivers/char/watchdog/Kconfig
> b/drivers/char/watchdog/Kconfig
> index 53f5538..40f2ce1 100644
> --- a/drivers/char/watchdog/Kconfig
> +++ b/drivers/char/watchdog/Kconfig
> @@ -616,6 +616,19 @@ config SH_WDT_MMAP
> If you say Y here, user applications will be able to mmap
> the
> WDT/CPG registers.
>
> +# Blackfin Architecture
> +
> +config BFIN_WDT
> + tristate "Blackfin On-Chip Watchdog Timer"
> + depends on WATCHDOG && BLACKFIN
> + ---help---
> + If you say yes here you will get support for the Blackfin
> On-Chip
> + Watchdog Timer. If you have one of these processors and wish
> to
> + have watchdog support enabled, say Y, otherwise say N.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called bfin_wdt.
> +
> # SPARC64 Architecture
>
> config WATCHDOG_CP1XXX
> diff --git a/drivers/char/watchdog/Makefile
> b/drivers/char/watchdog/Makefile
> index d90f649..86aae7e 100644
> --- a/drivers/char/watchdog/Makefile
> +++ b/drivers/char/watchdog/Makefile
> @@ -81,6 +81,9 @@ obj-$(CONFIG_WDT_RM9K_GPI) += rm9k_wdt.o
> # SUPERH Architecture
> obj-$(CONFIG_SH_WDT) += shwdt.o
>
> +# Blackfin Architecture
> +obj-$(CONFIG_BFIN_WDT) += bfin_wdt.o
> +
> # SPARC64 Architecture
>
> # Architecture Independant
> diff --git a/drivers/char/watchdog/bfin_wdt.c
> b/drivers/char/watchdog/bfin_wdt.c
> new file mode 100644
> index 0000000..309d279
> --- /dev/null
> +++ b/drivers/char/watchdog/bfin_wdt.c
> @@ -0,0 +1,490 @@
> +/*
> + * Blackfin On-Chip Watchdog Driver
> + * Supports BF53[123]/BF53[467]/BF54[2489]/BF561
> + *
> + * Originally based on softdog.c
> + * Copyright 2006-2007 Analog Devices Inc.
> + * Copyright 2006-2007 Michele d'Amico
> + * Copyright 1996 Alan Cox <alan@...hat.com>
> + *
> + * Enter bugs at http://blackfin.uclinux.org/
> + *
> + * Licensed under the GPL-2 or later.
> + */
> +
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/types.h>
> +#include <linux/timer.h>
> +#include <linux/miscdevice.h>
> +#include <linux/watchdog.h>
> +#include <linux/fs.h>
> +#include <linux/notifier.h>
> +#include <linux/reboot.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <asm/blackfin.h>
> +#include <asm/uaccess.h>
> +
> +#define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__,
> __LINE__, ## args)
> +#define stampit() stamp("here i am")
> +
> +#define WATCHDOG_NAME "bfin-wdt"
> +#define PFX WATCHDOG_NAME ": "
> +
> +/* The BF561 has two watchdogs (one per core), but since Linux
> + * only runs on core A, we'll just work with that one.
> + */
> +#ifdef BF561_FAMILY
> +# define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL()
> +# define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT()
> +# define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT()
> +# define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x)
> +# define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x)
> +# define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
> +#endif
> +
> +/* Bit in SWRST that indicates boot caused by watchdog */
> +#define SWRST_RESET_WDOG 0x4000
> +
> +/* Bit in WDOG_CTL that indicates watchdog has expired (WDR0) */
> +#define WDOG_EXPIRED 0x8000
> +
> +/* Masks for WDEV field in WDOG_CTL register */
> +#define ICTL_RESET 0x0
> +#define ICTL_NMI 0x2
> +#define ICTL_GPI 0x4
> +#define ICTL_NONE 0x6
> +#define ICTL_MASK 0x6
> +
> +/* Masks for WDEN field in WDOG_CTL register */
> +#define WDEN_MASK 0x0FF0
> +#define WDEN_ENABLE 0x0000
> +#define WDEN_DISABLE 0x0AD0
> +
> +/* some defaults */
> +#define WATCHDOG_TIMEOUT 20
> +
> +static unsigned int timeout = WATCHDOG_TIMEOUT;
> +static int nowayout = WATCHDOG_NOWAYOUT;
> +static struct watchdog_info bfin_wdt_info;
> +static unsigned long open_check;
> +static char expect_close;
> +static spinlock_t bfin_wdt_spinlock = SPIN_LOCK_UNLOCKED;
> +
> +/**
> + * bfin_wdt_keepalive - Keep the Userspace Watchdog Alive
> + *
> + * The Userspace watchdog got a KeepAlive: schedule the next
> timeout.
> + */
> +static int bfin_wdt_keepalive(void)
> +{
> + stampit();
> + bfin_write_WDOG_STAT(0);
> + return 0;
> +}
> +
> +/**
> + * bfin_wdt_stop - Stop the Watchdog
> + *
> + * Stops the on-chip watchdog.
> + */
> +static int bfin_wdt_stop(void)
> +{
> + stampit();
> + bfin_write_WDOG_CTL(WDEN_DISABLE);
> + return 0;
> +}
> +
> +/**
> + * bfin_wdt_start - Start the Watchdog
> + *
> + * Starts the on-chip watchdog. Automatically loads WDOG_CNT
> + * into WDOG_STAT for us.
> + */
> +static int bfin_wdt_start(void)
> +{
> + stampit();
> + bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET);
> + return 0;
> +}
> +
> +/**
> + * bfin_wdt_running - Check Watchdog status
> + *
> + * See if the watchdog is running.
> + */
> +static int bfin_wdt_running(void)
> +{
> + stampit();
> + return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
> +}
> +
> +/**
> + * bfin_wdt_set_timeout - Set the Userspace Watchdog timeout
> + * @t: new timeout value (in seconds)
> + *
> + * Translate the specified timeout in seconds into System Clock
> + * terms which is what the on-chip Watchdog requires.
> + */
> +static int bfin_wdt_set_timeout(unsigned long t)
> +{
> + u32 cnt;
> + unsigned long flags;
> +
> + stampit();
> +
> + cnt = t * get_sclk();
> + if (cnt < get_sclk()) {
> + printk(KERN_WARNING PFX "timeout value is too large
> \n");
> + return -EINVAL;
> + }
> +
> + spin_lock_irqsave(&bfin_wdt_spinlock, flags);
> + {
> + int run = bfin_wdt_running();
> + bfin_wdt_stop();
> + bfin_write_WDOG_CNT(cnt);
> + if (run) bfin_wdt_start();
> + }
> + spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
> +
> + timeout = t;
> +
> + return 0;
> +}
> +
> +/**
> + * bfin_wdt_open - Open the Device
> + * @inode: inode of device
> + * @file: file handle of device
> + *
> + * Watchdog device is opened and started.
> + */
> +static int bfin_wdt_open(struct inode *inode, struct file *file)
> +{
> + stampit();
> +
> + if (test_and_set_bit(0, &open_check))
> + return -EBUSY;
> +
> + if (nowayout)
> + __module_get(THIS_MODULE);
> +
> + bfin_wdt_keepalive();
> + bfin_wdt_start();
> +
> + return nonseekable_open(inode, file);
> +}
> +
> +/**
> + * bfin_wdt_close - Close the Device
> + * @inode: inode of device
> + * @file: file handle of device
> + *
> + * Watchdog device is closed and stopped.
> + */
> +static int bfin_wdt_release(struct inode *inode, struct file *file)
> +{
> + stampit();
> +
> + if (expect_close == 42) {
> + bfin_wdt_stop();
> + } else {
> + printk(KERN_CRIT PFX "Unexpected close, not stopping
> watchdog!\n");
> + bfin_wdt_keepalive();
> + }
> +
> + expect_close = 0;
> + clear_bit(0, &open_check);
> +
> + return 0;
> +}
> +
> +/**
> + * bfin_wdt_write - Write to Device
> + * @file: file handle of device
> + * @buf: buffer to write
> + * @count: length of buffer
> + * @ppos: offset
> + *
> + * Pings the watchdog on write.
> + */
> +static ssize_t bfin_wdt_write(struct file *file, const char __user
> *data,
> + size_t len, loff_t *ppos)
> +{
> + stampit();
> +
> + if (len) {
> + if (!nowayout) {
> + size_t i;
> +
> + /* In case it was set long ago */
> + expect_close = 0;
> +
> + for (i = 0; i != len; i++) {
> + char c;
> + if (get_user(c, data + i))
> + return -EFAULT;
> + if (c == 'V')
> + expect_close = 42;
> + }
> + }
> + bfin_wdt_keepalive();
> + }
> +
> + return len;
> +}
> +
> +/**
> + * bfin_wdt_ioctl - Query Device
> + * @inode: inode of device
> + * @file: file handle of device
> + * @cmd: watchdog command
> + * @arg: argument
> + *
> + * Query basic information from the device or ping it, as
> outlined by the
> + * watchdog API.
> + */
> +static int bfin_wdt_ioctl(struct inode *inode, struct file *file,
> + unsigned int cmd, unsigned long arg)
> +{
> + void __user *argp = (void __user *)arg;
> + int __user *p = argp;
> +
> + stampit();
> +
> + switch (cmd) {
> + default:
> + return -ENOTTY;
> +
> + case WDIOC_GETSUPPORT:
> + if (copy_to_user(argp, &bfin_wdt_info,
> sizeof(bfin_wdt_info)))
> + return -EFAULT;
> + else
> + return 0;
> +
> + case WDIOC_GETSTATUS:
> + case WDIOC_GETBOOTSTATUS:
> + return put_user(!!(_bfin_swrst &
> SWRST_RESET_WDOG), p);
> +
> + case WDIOC_KEEPALIVE:
> + bfin_wdt_keepalive();
> + return 0;
> +
> + case WDIOC_SETTIMEOUT: {
> + int new_timeout;
> +
> + if (get_user(new_timeout, p))
> + return -EFAULT;
> +
> + if (bfin_wdt_set_timeout(new_timeout))
> + return -EINVAL;
> + }
> + /* Fall */
> + case WDIOC_GETTIMEOUT:
> + return put_user(timeout, p);
> +
> + case WDIOC_SETOPTIONS: {
> + unsigned long flags;
> + int options, ret = -EINVAL;
> +
> + if (get_user(options, p))
> + return -EFAULT;
> +
> + spin_lock_irqsave(&bfin_wdt_spinlock, flags);
> +
> + if (options & WDIOS_DISABLECARD) {
> + bfin_wdt_stop();
> + ret = 0;
> + }
> +
> + if (options & WDIOS_ENABLECARD) {
> + bfin_wdt_start();
> + ret = 0;
> + }
> +
> + spin_unlock_irqrestore(&bfin_wdt_spinlock,
> flags);
> +
> + return ret;
> + }
> + }
> +}
> +
> +/**
> + * bfin_wdt_notify_sys - Notifier Handler
> + * @this: notifier block
> + * @code: notifier event
> + * @unused: unused
> + *
> + * Handles specific events, such as turning off the watchdog
> during a
> + * shutdown event.
> + */
> +static int bfin_wdt_notify_sys(struct notifier_block *this, unsigned
> long code,
> + void *unused)
> +{
> + stampit();
> +
> + if (code == SYS_DOWN || code == SYS_HALT)
> + bfin_wdt_stop();
> +
> + return NOTIFY_DONE;
> +}
> +
> +#ifdef CONFIG_PM
> +static int state_before_suspend;
> +
> +/**
> + * bfin_wdt_suspend - suspend the watchdog
> + * @pdev: device being suspended
> + * @state: requested suspend state
> + *
> + * Remember if the watchdog was running and stop it.
> + * TODO: is this even right? Doesn't seem to be any
> + * standard in the watchdog world ...
> + */
> +static int bfin_wdt_suspend(struct platform_device *pdev,
> pm_message_t state)
> +{
> + stampit();
> +
> + state_before_suspend = bfin_wdt_running();
> + bfin_wdt_stop();
> +
> + return 0;
> +}
> +
> +/**
> + * bfin_wdt_resume - resume the watchdog
> + * @pdev: device being resumed
> + *
> + * If the watchdog was running, turn it back on.
> + */
> +static int bfin_wdt_resume(struct platform_device *pdev)
> +{
> + stampit();
> +
> + if (state_before_suspend) {
> + bfin_wdt_set_timeout(timeout);
> + bfin_wdt_start();
> + }
> +
> + return 0;
> +}
> +#else
> +# define bfin_wdt_suspend NULL
> +# define bfin_wdt_resume NULL
> +#endif
> +
> +static struct platform_device bfin_wdt_device = {
> + .name = WATCHDOG_NAME,
> + .id = -1,
> +};
> +
> +static struct platform_driver bfin_wdt_driver = {
> + .driver = {
> + .name = WATCHDOG_NAME,
> + .owner = THIS_MODULE,
> + },
> + .suspend = bfin_wdt_suspend,
> + .resume = bfin_wdt_resume,
> +};
> +
> +static struct file_operations bfin_wdt_fops = {
> + .owner = THIS_MODULE,
> + .llseek = no_llseek,
> + .write = bfin_wdt_write,
> + .ioctl = bfin_wdt_ioctl,
> + .open = bfin_wdt_open,
> + .release = bfin_wdt_release,
> +};
> +
> +static struct miscdevice bfin_wdt_miscdev = {
> + .minor = WATCHDOG_MINOR,
> + .name = "watchdog",
> + .fops = &bfin_wdt_fops,
> +};
> +
> +static struct watchdog_info bfin_wdt_info = {
> + .identity = "Blackfin Watchdog",
> + .options = WDIOF_SETTIMEOUT |
> + WDIOF_KEEPALIVEPING |
> + WDIOF_MAGICCLOSE,
> +};
> +
> +static struct notifier_block bfin_wdt_notifier = {
> + .notifier_call = bfin_wdt_notify_sys,
> +};
> +
> +/**
> + * bfin_wdt_init - Initialize module
> + *
> + * Registers the device and notifier handler. Actual device
> + * initialization is handled by bfin_wdt_open().
> + */
> +static int __init bfin_wdt_init(void)
> +{
> + int ret;
> +
> + stampit();
> +
> + /* Check that the timeout value is within range */
> + if (bfin_wdt_set_timeout(timeout))
> + return -EINVAL;
> +
> + /* Since this is an on-chip device and needs no
> board-specific
> + * resources, we'll handle all the platform device stuff
> here.
> + */
> + ret = platform_device_register(&bfin_wdt_device);
> + if (ret)
> + return ret;
> +
> + ret = platform_driver_probe(&bfin_wdt_driver, NULL);
> + if (ret)
> + return ret;
> +
> + ret = register_reboot_notifier(&bfin_wdt_notifier);
> + if (ret) {
> + printk(KERN_ERR PFX "cannot register reboot notifier
> (err=%d)\n", ret);
> + return ret;
> + }
> +
> + ret = misc_register(&bfin_wdt_miscdev);
> + if (ret) {
> + printk(KERN_ERR PFX "cannot register miscdev on minor=
> %d (err=%d)\n",
> + WATCHDOG_MINOR, ret);
> + unregister_reboot_notifier(&bfin_wdt_notifier);
> + return ret;
> + }
> +
> + printk(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%
> d)\n",
> + timeout, nowayout);
> +
> + return 0;
> +}
> +
> +/**
> + * bfin_wdt_exit - Deinitialize module
> + *
> + * Unregisters the device and notifier handler. Actual device
> + * deinitialization is handled by bfin_wdt_close().
> + */
> +static void __exit bfin_wdt_exit(void)
> +{
> + misc_deregister(&bfin_wdt_miscdev);
> + unregister_reboot_notifier(&bfin_wdt_notifier);
> +}
> +
> +module_init(bfin_wdt_init);
> +module_exit(bfin_wdt_exit);
> +
> +MODULE_AUTHOR("Michele d'Amico, Mike Frysinger
> <vapier@...too.org>");
> +MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
> +
> +module_param(timeout, uint, 0);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.
> (1<=timeout<=((2^32)/SCLK), default="
> __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
>
> +
> +module_param(nowayout, int, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started
> (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
>
> --
> 1.5.2
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