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Message-ID: <5289FE60.2040207@ti.com>
Date: Mon, 18 Nov 2013 13:47:44 +0200
From: "ivan.khoronzhuk" <ivan.khoronzhuk@...com>
To: Guenter Roeck <linux@...ck-us.net>,
Santosh Shilimkar <santosh.shilimkar@...com>, <wim@...ana.be>,
<nsekhar@...com>, <linux-watchdog@...r.kernel.org>,
<devicetree@...r.kernel.org>
CC: <grant.likely@...aro.org>, <rob.herring@...xeda.com>,
<pawel.moll@....com>, <mark.rutland@....com>,
<swarren@...dotorg.org>, <galak@...nel.crashing.org>,
<ijc+devicetree@...lion.org.uk>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>
Subject: Re: Fwd: [PATCH 1/8] watchdog: davinci: change driver to use WDT
core
On 11/16/2013 10:29 PM, Guenter Roeck wrote:
> On 11/06/2013 03:31 AM, ivan.khoronzhuk wrote:
>> To reduce code duplicate and increase code readability use WDT core
>> code to handle WDT interface.
>>
>> Remove io_lock as the WDT core uses mutex to lock each wdt device.
>> Remove wdt_state as the WDT core track state with its own variable.
>>
>> The watchdog_init_timeout() can read timeout value from timeout-sec
>> property if the passed value is out of bounds. So set initial
>> heartbeat value more than max value in order to initialize heartbeat
>> in next way. If heartbeat is not set thought module parameter, try
>> to read it's value from WDT node timeout-sec property. If node has
>> no one, use default value.
>>
>> The heartbeat is hold in wdd->timeout by WDT core, so use it in
>> order to set timeout period.
>>
>> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@...com>
>> ---
>> drivers/watchdog/Kconfig | 1 +
>> drivers/watchdog/davinci_wdt.c | 150
>> ++++++++++------------------------------
>> 2 files changed, 38 insertions(+), 113 deletions(-)
>>
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index d1d53f3..2c954b5 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -271,6 +271,7 @@ config IOP_WATCHDOG
>> config DAVINCI_WATCHDOG
>> tristate "DaVinci watchdog"
>> depends on ARCH_DAVINCI
>> + select WATCHDOG_CORE
>> help
>> Say Y here if to include support for the watchdog timer
>> in the DaVinci DM644x/DM646x processors.
>> diff --git a/drivers/watchdog/davinci_wdt.c
>> b/drivers/watchdog/davinci_wdt.c
>> index bead774..a6eef71 100644
>> --- a/drivers/watchdog/davinci_wdt.c
>> +++ b/drivers/watchdog/davinci_wdt.c
>> @@ -3,7 +3,7 @@
>> *
>> * Watchdog driver for DaVinci DM644x/DM646x processors
>> *
>> - * Copyright (C) 2006 Texas Instruments.
>> + * Copyright (C) 2013 Texas Instruments.
>
> 2006-2013
>
Ok
>> *
>> * 2007 (c) MontaVista Software, Inc. This file is licensed under
>> * the terms of the GNU General Public License version 2. This program
>> @@ -15,18 +15,12 @@
>> #include <linux/moduleparam.h>
>> #include <linux/types.h>
>> #include <linux/kernel.h>
>> -#include <linux/fs.h>
>> -#include <linux/miscdevice.h>
>> #include <linux/watchdog.h>
>> #include <linux/init.h>
>> -#include <linux/bitops.h>
>> #include <linux/platform_device.h>
>> -#include <linux/spinlock.h>
>> -#include <linux/uaccess.h>
>> #include <linux/io.h>
>> #include <linux/device.h>
>> #include <linux/clk.h>
>> -#include <linux/slab.h>
>> #include <linux/err.h>
>>
>> #define MODULE_NAME "DAVINCI-WDT: "
>> @@ -61,31 +55,13 @@
>> #define WDKEY_SEQ0 (0xa5c6 << 16)
>> #define WDKEY_SEQ1 (0xda7e << 16)
>>
>> -static int heartbeat = DEFAULT_HEARTBEAT;
>> -
>> -static DEFINE_SPINLOCK(io_lock);
>> -static unsigned long wdt_status;
>> -#define WDT_IN_USE 0
>> -#define WDT_OK_TO_CLOSE 1
>> -#define WDT_REGION_INITED 2
>> -#define WDT_DEVICE_INITED 3
>> -
>> +static int heartbeat = MAX_HEARTBEAT + 1;
>
> Initializing it with 0 (ie not at all) would be just as good. Also see
> below.
>
Ok
>> static void __iomem *wdt_base;
>> struct clk *wdt_clk;
>> +static struct watchdog_device wdt_wdd;
>>
>> -static void wdt_service(void)
>> -{
>> - spin_lock(&io_lock);
>> -
>> - /* put watchdog in service state */
>> - iowrite32(WDKEY_SEQ0, wdt_base + WDTCR);
>> - /* put watchdog in active state */
>> - iowrite32(WDKEY_SEQ1, wdt_base + WDTCR);
>> -
>> - spin_unlock(&io_lock);
>> -}
>> -
>> -static void wdt_enable(void)
>> +/* davinci_wdt_start - enable watchdog */
>
> That comment doesn't really provide much value.
>
>> +static int davinci_wdt_start(struct watchdog_device *wdd)
>> {
>> u32 tgcr;
>> u32 timer_margin;
>> @@ -93,8 +69,6 @@ static void wdt_enable(void)
>>
>> wdt_freq = clk_get_rate(wdt_clk);
>>
>> - spin_lock(&io_lock);
>> -
>> /* disable, internal clock source */
>> iowrite32(0, wdt_base + TCR);
>> /* reset timer, set mode to 64-bit watchdog, and unreset */
>> @@ -105,9 +79,9 @@ static void wdt_enable(void)
>> iowrite32(0, wdt_base + TIM12);
>> iowrite32(0, wdt_base + TIM34);
>> /* set timeout period */
>> - timer_margin = (((u64)heartbeat * wdt_freq) & 0xffffffff);
>> + timer_margin = (((u64)wdd->timeout * wdt_freq) & 0xffffffff);
>> iowrite32(timer_margin, wdt_base + PRD12);
>> - timer_margin = (((u64)heartbeat * wdt_freq) >> 32);
>> + timer_margin = (((u64)wdd->timeout * wdt_freq) >> 32);
>> iowrite32(timer_margin, wdt_base + PRD34);
>> /* enable run continuously */
>> iowrite32(ENAMODE12_PERIODIC, wdt_base + TCR);
>> @@ -119,84 +93,28 @@ static void wdt_enable(void)
>> iowrite32(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR);
>> /* put watchdog in active state */
>> iowrite32(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR);
>> -
>> - spin_unlock(&io_lock);
>> -}
>> -
>> -static int davinci_wdt_open(struct inode *inode, struct file *file)
>> -{
>> - if (test_and_set_bit(WDT_IN_USE, &wdt_status))
>> - return -EBUSY;
>> -
>> - wdt_enable();
>> -
>> - return nonseekable_open(inode, file);
>> + return 0;
>> }
>>
>> -static ssize_t
>> -davinci_wdt_write(struct file *file, const char *data, size_t len,
>> - loff_t *ppos)
>> +static int davinci_wdt_ping(struct watchdog_device *wdd)
>> {
>> - if (len)
>> - wdt_service();
>> -
>> - return len;
>> + /* put watchdog in service state */
>> + iowrite32(WDKEY_SEQ0, wdt_base + WDTCR);
>> + /* put watchdog in active state */
>> + iowrite32(WDKEY_SEQ1, wdt_base + WDTCR);
>> + return 0;
>> }
>>
>> -static const struct watchdog_info ident = {
>> +static const struct watchdog_info davinci_wdt_info = {
>> .options = WDIOF_KEEPALIVEPING,
>> .identity = "DaVinci Watchdog",
>> };
>>
>> -static long davinci_wdt_ioctl(struct file *file,
>> - unsigned int cmd, unsigned long arg)
>> -{
>> - int ret = -ENOTTY;
>> -
>> - switch (cmd) {
>> - case WDIOC_GETSUPPORT:
>> - ret = copy_to_user((struct watchdog_info *)arg, &ident,
>> - sizeof(ident)) ? -EFAULT : 0;
>> - break;
>> -
>> - case WDIOC_GETSTATUS:
>> - case WDIOC_GETBOOTSTATUS:
>> - ret = put_user(0, (int *)arg);
>> - break;
>> -
>> - case WDIOC_KEEPALIVE:
>> - wdt_service();
>> - ret = 0;
>> - break;
>> -
>> - case WDIOC_GETTIMEOUT:
>> - ret = put_user(heartbeat, (int *)arg);
>> - break;
>> - }
>> - return ret;
>> -}
>> -
>> -static int davinci_wdt_release(struct inode *inode, struct file *file)
>> -{
>> - wdt_service();
>> - clear_bit(WDT_IN_USE, &wdt_status);
>> -
>> - return 0;
>> -}
>> -
>> -static const struct file_operations davinci_wdt_fops = {
>> - .owner = THIS_MODULE,
>> - .llseek = no_llseek,
>> - .write = davinci_wdt_write,
>> - .unlocked_ioctl = davinci_wdt_ioctl,
>> - .open = davinci_wdt_open,
>> - .release = davinci_wdt_release,
>> -};
>> -
>> -static struct miscdevice davinci_wdt_miscdev = {
>> - .minor = WATCHDOG_MINOR,
>> - .name = "watchdog",
>> - .fops = &davinci_wdt_fops,
>> +static const struct watchdog_ops davinci_wdt_ops = {
>> + .owner = THIS_MODULE,
>> + .start = davinci_wdt_start,
>> + .stop = davinci_wdt_ping,
>> + .ping = davinci_wdt_ping,
>> };
>>
>> static int davinci_wdt_probe(struct platform_device *pdev)
>> @@ -204,6 +122,7 @@ static int davinci_wdt_probe(struct
>> platform_device *pdev)
>> int ret = 0;
>> struct device *dev = &pdev->dev;
>> struct resource *wdt_mem;
>> + struct watchdog_device *wdd;
>>
>> wdt_clk = devm_clk_get(dev, NULL);
>> if (WARN_ON(IS_ERR(wdt_clk)))
>> @@ -211,29 +130,35 @@ static int davinci_wdt_probe(struct
>> platform_device *pdev)
>>
>> clk_prepare_enable(wdt_clk);
>>
>> - if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
>> - heartbeat = DEFAULT_HEARTBEAT;
>> + wdd = &wdt_wdd;
>> + wdd->info = &davinci_wdt_info;
>> + wdd->ops = &davinci_wdt_ops;
>> + wdd->min_timeout = 1;
>> + wdd->max_timeout = MAX_HEARTBEAT;
>> + wdd->timeout = DEFAULT_HEARTBEAT;
>> +
>> + if (heartbeat)
>> + watchdog_init_timeout(wdd, heartbeat, dev);
>> +
> The if statement here is unnecessary. Actually, you always want to call
> watchdog_init_timeout()
> to ensure that it gets the configuration from fdt if available.
>
Ok
>> + dev_info(dev, "heartbeat %d sec\n", wdd->timeout);
>>
>> - dev_info(dev, "heartbeat %d sec\n", heartbeat);
>> + watchdog_set_nowayout(wdd, WATCHDOG_NOWAYOUT);
>>
>> wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> wdt_base = devm_ioremap_resource(dev, wdt_mem);
>> if (IS_ERR(wdt_base))
>> return PTR_ERR(wdt_base);
>>
>> - ret = misc_register(&davinci_wdt_miscdev);
>> - if (ret < 0) {
>> - dev_err(dev, "cannot register misc device\n");
>> - } else {
>> - set_bit(WDT_DEVICE_INITED, &wdt_status);
>> - }
>> + ret = watchdog_register_device(wdd);
>> + if (ret < 0)
>> + dev_err(dev, "cannot register watchdog device\n");
>>
>> return ret;
>> }
>>
>> static int davinci_wdt_remove(struct platform_device *pdev)
>> {
>> - misc_deregister(&davinci_wdt_miscdev);
>> + watchdog_unregister_device(&wdt_wdd);
>> clk_disable_unprepare(wdt_clk);
>>
>> return 0;
>> @@ -267,5 +192,4 @@ MODULE_PARM_DESC(heartbeat,
>> __MODULE_STRING(DEFAULT_HEARTBEAT));
>>
>> MODULE_LICENSE("GPL");
>> -MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
>> MODULE_ALIAS("platform:watchdog");
>>
> You might want to rename the platform driver to something like
> davinci-wdt and change the MODULE_ALIAS
> accordingly.
>
Yes, it could be changed but not in this patch.
> Guenter
>
>
--
Regards,
Ivan Khoronzhuk
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