Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752556Ab2EaKho (ORCPT ); Thu, 31 May 2012 06:37:44 -0400 Received: from skyrme.org ([193.175.80.135]:52023 "EHLO skyrme.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750849Ab2EaKhn (ORCPT ); Thu, 31 May 2012 06:37:43 -0400 Date: 31 May 2012 10:37:38 +0000 Message-Id: <1338460658-16067-1-git-send-email-oskar@scara.com> From: "Oskar Schirmer" To: linux-kernel@vger.kernel.org Cc: "Oskar Schirmer" , "Wim Van Sebroeck" , "Wolfram Sang" Subject: [PATCH] watchdog/imx2+: add support for pretimeout interrupt functionality X-Mailer: git-send-email 1.6.0.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6920 Lines: 237 This watchdog device provides pretimeout facilities: Set some timeout value and get informed about imminent watchdog activity thru interrupt. Allow user to wait for this interrupt thru poll(2), and to clear it thru read(2). Signed-off-by: Oskar Schirmer Cc: Wim Van Sebroeck Cc: Wolfram Sang --- drivers/watchdog/imx2_wdt.c | 129 ++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 128 insertions(+), 1 deletions(-) diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c index bcfab2b..09172c8 100644 --- a/drivers/watchdog/imx2_wdt.c +++ b/drivers/watchdog/imx2_wdt.c @@ -21,11 +21,16 @@ */ #include +#include #include #include #include #include #include +#include +#include +#include +#include #include #include #include @@ -49,6 +54,11 @@ #define IMX2_WDT_WRSR 0x04 /* Reset Status Register */ #define IMX2_WDT_WRSR_TOUT (1 << 1) /* -> Reset due to Timeout */ +#define IMX2_WDT_WICT 0x06 /* Interrupt Control Reg */ +#define IMX2_WDT_WICT_WIE (1 << 15) /* -> Interrupt Enable */ +#define IMX2_WDT_WICT_WTIS (1 << 14) /* -> Timer Interrupt Status */ +#define IMX2_WDT_WICT_WICT (0xFF << 0) /* -> Interrupt Count Timeout */ + #define IMX2_WDT_MAX_TIME 128 #define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */ @@ -64,6 +74,11 @@ static struct { unsigned timeout; unsigned long status; struct timer_list timer; /* Pings the watchdog when closed */ + int irq; + spinlock_t read_lock; + wait_queue_head_t read_q; + unsigned char pretimer_once; + unsigned char pretimer_data; } imx2_wdt; static struct miscdevice imx2_wdt_miscdev; @@ -81,7 +96,8 @@ MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" static const struct watchdog_info imx2_wdt_info = { .identity = "imx2+ watchdog", - .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, + .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | + WDIOF_PRETIMEOUT, }; static inline void imx2_wdt_setup(void) @@ -148,6 +164,28 @@ static void imx2_wdt_set_timeout(int new_timeout) __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR); } +static void imx2_wdt_set_pretimeout(int new_pretimeout) +{ + u16 val = new_pretimeout; + + if (val > 0) + val = (val << 1) | IMX2_WDT_WICT_WIE; + __raw_writew(val, imx2_wdt.base + IMX2_WDT_WICT); +} + +static void imx2_wdt_interrupt(int irq, void *dev_id) +{ + u16 val; + spin_lock(&imx2_wdt.read_lock); + val = __raw_readw(imx2_wdt.base + IMX2_WDT_WICT); + if (val & IMX2_WDT_WICT_WTIS) { + __raw_writew(val, imx2_wdt.base + IMX2_WDT_WICT); + imx2_wdt.pretimer_data = 1; + } + wake_up_interruptible(&imx2_wdt.read_q); + spin_unlock(&imx2_wdt.read_lock); +} + static int imx2_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status)) @@ -210,6 +248,26 @@ static long imx2_wdt_ioctl(struct file *file, unsigned int cmd, case WDIOC_GETTIMEOUT: return put_user(imx2_wdt.timeout, p); + case WDIOC_SETPRETIMEOUT: + if (get_user(new_value, p)) + return -EFAULT; + if ((new_value < 0) || (new_value >= IMX2_WDT_MAX_TIME)) + return -EINVAL; + if (imx2_wdt.irq < 0) + return -EINVAL; + if (imx2_wdt.pretimer_once) + return -EPERM; + imx2_wdt.pretimer_once = 1; + imx2_wdt_set_pretimeout(new_value); + + case WDIOC_GETPRETIMEOUT: + val = __raw_readw(imx2_wdt.base + IMX2_WDT_WICT); + if (val & IMX2_WDT_WICT_WIE) + val = (val & IMX2_WDT_WICT_WICT) >> 1; + else + val = 0; + return put_user(val, p); + default: return -ENOTTY; } @@ -237,6 +295,59 @@ static ssize_t imx2_wdt_write(struct file *file, const char __user *data, return len; } +static ssize_t imx2_wdt_read(struct file *file, char __user *data, + size_t count, loff_t *ppos) +{ + wait_queue_t wait; + unsigned long flags; + + if (count <= 0) + return 0; + + spin_lock_irqsave(&imx2_wdt.read_lock, flags); + while (!imx2_wdt.pretimer_data) { + if (file->f_flags & O_NONBLOCK) { + spin_unlock_irqrestore(&imx2_wdt.read_lock, flags); + return -EAGAIN; + } + + init_waitqueue_entry(&wait, current); + add_wait_queue(&imx2_wdt.read_q, &wait); + set_current_state(TASK_INTERRUPTIBLE); + spin_unlock_irqrestore(&imx2_wdt.read_lock, flags); + schedule(); + spin_lock_irqsave(&imx2_wdt.read_lock, flags); + remove_wait_queue(&imx2_wdt.read_q, &wait); + + if (signal_pending(current)) { + spin_unlock_irqrestore(&imx2_wdt.read_lock, flags); + return -ERESTARTSYS; + } + } + + imx2_wdt.pretimer_data = 0; + spin_unlock_irqrestore(&imx2_wdt.read_lock, flags); + if (copy_to_user(data, &imx2_wdt.pretimer_data, 1)) + return -EFAULT; + + return 1; +} + +static unsigned int imx2_wdt_poll(struct file *file, poll_table *wait) +{ + unsigned int mask = 0; + unsigned long flags; + + poll_wait(file, &imx2_wdt.read_q, wait); + + spin_lock_irqsave(&imx2_wdt.read_lock, flags); + if (imx2_wdt.pretimer_data) + mask |= POLLIN | POLLRDNORM; + spin_unlock_irqrestore(&imx2_wdt.read_lock, flags); + + return mask; +} + static const struct file_operations imx2_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, @@ -244,6 +355,8 @@ static const struct file_operations imx2_wdt_fops = { .open = imx2_wdt_open, .release = imx2_wdt_close, .write = imx2_wdt_write, + .read = imx2_wdt_read, + .poll = imx2_wdt_poll, }; static struct miscdevice imx2_wdt_miscdev = { @@ -282,6 +395,16 @@ static int __init imx2_wdt_probe(struct platform_device *pdev) setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0); + init_waitqueue_head(&imx2_wdt.read_q); + spin_lock_init(&imx2_wdt.read_lock); + imx2_wdt.irq = platform_get_irq(pdev, 0); + if (imx2_wdt.irq >= 0) { + ret = request_irq(imx2_wdt.irq, imx2_wdt_interrupt, + 0, "watchdog", pdev); + if (ret) + goto fail; + } + imx2_wdt_miscdev.parent = &pdev->dev; ret = misc_register(&imx2_wdt_miscdev); if (ret) @@ -294,6 +417,8 @@ static int __init imx2_wdt_probe(struct platform_device *pdev) fail: imx2_wdt_miscdev.parent = NULL; + if (imx2_wdt.irq >= 0) + free_irq(imx2_wdt.irq, pdev); clk_put(imx2_wdt.clk); return ret; } @@ -301,6 +426,8 @@ fail: static int __exit imx2_wdt_remove(struct platform_device *pdev) { misc_deregister(&imx2_wdt_miscdev); + if (imx2_wdt.irq >= 0) + free_irq(imx2_wdt.irq, pdev); if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) { del_timer_sync(&imx2_wdt.timer); -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/