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SubjectRe: [PATCH v2 06/11] watchdog/hpwdt: Modify to use watchdog core.
Hi Jerry,

On Sun, Feb 11, 2018 at 10:21:06PM -0700, Jerry Hoemann wrote:
> Follow Documentation/watchdog/convert_drivers_to_kernel_api.txt to
> convert hpwdt from legacy watchdog driver to use the watchdog core.
>
> Removed functions: hpwdt_open, hpwdt_release, hpwdt_write, hpwdt_ioctl
> Removed data structures: hpwdt_fops, hpwdt_miscdev, watchdog_device
> Modified functions: hpwdt_start, hpwdt_stop, hpwdt_ping, hpwdt_gettimeleft
> Added functions: hpwdt_settimeout
> Added structures: watchdog_device
>
> Signed-off-by: Jerry Hoemann <jerry.hoemann@hpe.com>

I think it would be better to use
dev_emerg()
dev_crit()
dev_alert()
dev_err()
dev_warn()
dev_notice()

instead of pr_* functions now when we have a device to use.

> ---
> drivers/watchdog/hpwdt.c | 251 ++++++++++++-----------------------------------
> 1 file changed, 63 insertions(+), 188 deletions(-)
>
> diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
> index dead59f9ca80..740d0c633204 100644
> --- a/drivers/watchdog/hpwdt.c
> +++ b/drivers/watchdog/hpwdt.c
> @@ -14,18 +14,13 @@
> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
> #include <linux/device.h>
> -#include <linux/fs.h>
> -#include <linux/io.h>
> -#include <linux/bitops.h>
> #include <linux/kernel.h>
> -#include <linux/miscdevice.h>
> #include <linux/module.h>
> #include <linux/moduleparam.h>
> #include <linux/pci.h>
> -#include <linux/pci_ids.h>
> #include <linux/types.h>
> -#include <linux/uaccess.h>
> #include <linux/watchdog.h>
> +
> #include <asm/nmi.h>
>
> #define HPWDT_VERSION "1.4.0"
> @@ -40,8 +35,6 @@ static bool nowayout = WATCHDOG_NOWAYOUT;
> #ifdef CONFIG_HPWDT_NMI_DECODING
> static unsigned int allow_kdump = 1;
> #endif
> -static char expect_release;
> -static unsigned long hpwdt_is_open;
>
> static void __iomem *pci_mem_addr; /* the PCI-memory address */
> static unsigned long __iomem *hpwdt_nmistat;
> @@ -55,53 +48,58 @@ static const struct pci_device_id hpwdt_devices[] = {
> };
> MODULE_DEVICE_TABLE(pci, hpwdt_devices);
>
> +static struct watchdog_device hpwdt_dev;
>
> /*
> * Watchdog operations
> */
> -static void hpwdt_start(void)
> +static int hpwdt_start(struct watchdog_device *dev)
> {
> - reload = SECS_TO_TICKS(soft_margin);
> + reload = SECS_TO_TICKS(dev->timeout);
> +
> iowrite16(reload, hpwdt_timer_reg);
> iowrite8(0x85, hpwdt_timer_con);
> +
> + return 0;
> }
>
> -static void hpwdt_stop(void)
> +static int hpwdt_stop(struct watchdog_device *dev)
> {
> unsigned long data;
>
> data = ioread8(hpwdt_timer_con);
> data &= 0xFE;
> iowrite8(data, hpwdt_timer_con);
> + return 0;
> }
>
> -static void hpwdt_ping(void)
> -{
> - iowrite16(reload, hpwdt_timer_reg);
> -}
> -
> -static int hpwdt_change_timer(int new_margin)
> +static int hpwdt_ping(struct watchdog_device *dev)
> {
> - if (new_margin < 1 || new_margin > HPWDT_MAX_TIMER) {
> - pr_warn("New value passed in is invalid: %d seconds\n",
> - new_margin);
> - return -EINVAL;
> - }
> + reload = SECS_TO_TICKS(dev->timeout);
>
> - soft_margin = new_margin;
> - pr_debug("New timer passed in is %d seconds\n", new_margin);
> - reload = SECS_TO_TICKS(soft_margin);
> + iowrite16(reload, hpwdt_timer_reg);
>
> return 0;
> }
>
> -static int hpwdt_time_left(void)
> +static unsigned int hpwdt_gettimeleft(struct watchdog_device *dev)
> {
> return TICKS_TO_SECS(ioread16(hpwdt_timer_reg));
> }
>
> +static int hpwdt_settimeout(struct watchdog_device *dev, unsigned int val)
> +{
> + pr_debug("settimeout = %d\n", val);

dev_dbg()


> +
> + soft_margin = dev->timeout = val;

No need to update soft_margin

> + hpwdt_ping(dev);
> +
> + return 0;
> +}
> +
> #ifdef CONFIG_HPWDT_NMI_DECODING /* { */
> -static int hpwdt_my_nmi(void)
> +
> +static unsigned int hpwdt_my_nmi(void)
> {
> return ioread8(hpwdt_nmistat) & 0x6;
> }
> @@ -128,8 +126,10 @@ static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
> if ((ulReason == NMI_UNKNOWN) && !mynmi)
> return NMI_DONE;
>
> + pr_debug("nmi: ulReason=%d, mynmi=0x%0x\n", ulReason, mynmi);

dev_dbg()

> +
> if (allow_kdump)
> - hpwdt_stop();
> + hpwdt_stop(&hpwdt_dev);
>
> panic_msg[0] = hexdigit((mynmi>>4)&0xf);
> panic_msg[1] = hexdigit(mynmi&0xf);
> @@ -140,68 +140,6 @@ static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
> }
> #endif /* } */
>
> -/*
> - * /dev/watchdog handling
> - */
> -static int hpwdt_open(struct inode *inode, struct file *file)
> -{
> - /* /dev/watchdog can only be opened once */
> - if (test_and_set_bit(0, &hpwdt_is_open))
> - return -EBUSY;
> -
> - /* Start the watchdog */
> - hpwdt_start();
> - hpwdt_ping();
> -
> - return nonseekable_open(inode, file);
> -}
> -
> -static int hpwdt_release(struct inode *inode, struct file *file)
> -{
> - /* Stop the watchdog */
> - if (expect_release == 42) {
> - hpwdt_stop();
> - } else {
> - pr_crit("Unexpected close, not stopping watchdog!\n");
> - hpwdt_ping();
> - }
> -
> - expect_release = 0;
> -
> - /* /dev/watchdog is being closed, make sure it can be re-opened */
> - clear_bit(0, &hpwdt_is_open);
> -
> - return 0;
> -}
> -
> -static ssize_t hpwdt_write(struct file *file, const char __user *data,
> - size_t len, loff_t *ppos)
> -{
> - /* See if we got the magic character 'V' and reload the timer */
> - if (len) {
> - if (!nowayout) {
> - size_t i;
> -
> - /* note: just in case someone wrote the magic character
> - * five months ago... */
> - expect_release = 0;
> -
> - /* scan to see whether or not we got the magic char. */
> - for (i = 0; i != len; i++) {
> - char c;
> - if (get_user(c, data + i))
> - return -EFAULT;
> - if (c == 'V')
> - expect_release = 42;
> - }
> - }
> -
> - /* someone wrote to us, we should reload the timer */
> - hpwdt_ping();
> - }
> -
> - return len;
> -}
>
> static const struct watchdog_info hpwdt_info = {
> .options = WDIOF_SETTIMEOUT |
> @@ -210,90 +148,10 @@ static const struct watchdog_info hpwdt_info = {
> .identity = "HPE iLO2+ HW Watchdog Timer",
> };
>
> -static long hpwdt_ioctl(struct file *file, unsigned int cmd,
> - unsigned long arg)
> -{
> - void __user *argp = (void __user *)arg;
> - int __user *p = argp;
> - int new_margin, options;
> - int ret = -ENOTTY;
> -
> - switch (cmd) {
> - case WDIOC_GETSUPPORT:
> - ret = 0;
> - if (copy_to_user(argp, &hpwdt_info, sizeof(hpwdt_info)))
> - ret = -EFAULT;
> - break;
> -
> - case WDIOC_GETSTATUS:
> - case WDIOC_GETBOOTSTATUS:
> - ret = put_user(0, p);
> - break;
> -
> - case WDIOC_KEEPALIVE:
> - hpwdt_ping();
> - ret = 0;
> - break;
> -
> - case WDIOC_SETOPTIONS:
> - ret = get_user(options, p);
> - if (ret)
> - break;
> -
> - if (options & WDIOS_DISABLECARD)
> - hpwdt_stop();
> -
> - if (options & WDIOS_ENABLECARD) {
> - hpwdt_start();
> - hpwdt_ping();
> - }
> - break;
> -
> - case WDIOC_SETTIMEOUT:
> - ret = get_user(new_margin, p);
> - if (ret)
> - break;
> -
> - ret = hpwdt_change_timer(new_margin);
> - if (ret)
> - break;
> -
> - hpwdt_ping();
> - /* Fall */
> - case WDIOC_GETTIMEOUT:
> - ret = put_user(soft_margin, p);
> - break;
> -
> - case WDIOC_GETTIMELEFT:
> - ret = put_user(hpwdt_time_left(), p);
> - break;
> - }
> - return ret;
> -}
> -
> -/*
> - * Kernel interfaces
> - */
> -static const struct file_operations hpwdt_fops = {
> - .owner = THIS_MODULE,
> - .llseek = no_llseek,
> - .write = hpwdt_write,
> - .unlocked_ioctl = hpwdt_ioctl,
> - .open = hpwdt_open,
> - .release = hpwdt_release,
> -};
> -
> -static struct miscdevice hpwdt_miscdev = {
> - .minor = WATCHDOG_MINOR,
> - .name = "watchdog",
> - .fops = &hpwdt_fops,
> -};
> -
> /*
> * Init & Exit
> */
>
> -
> static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
> {
> #ifdef CONFIG_HPWDT_NMI_DECODING /* { */
> @@ -311,10 +169,7 @@ static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
> if (retval)
> goto error2;
>
> - dev_info(&dev->dev,
> - "HPE Watchdog Timer Driver: NMI decoding initialized"
> - ", allow kernel dump: %s (default = 1/ON)\n",
> - (allow_kdump == 0) ? "OFF" : "ON");
> + dev_info(&dev->dev, "HPE Watchdog Timer Driver: NMI decoding initialized");
> return 0;
>
> error2:
> @@ -381,31 +236,32 @@ static int hpwdt_probe(struct pci_dev *dev, const struct pci_device_id *ent)
> hpwdt_timer_con = pci_mem_addr + 0x72;
>
> /* Make sure that timer is disabled until /dev/watchdog is opened */
> - hpwdt_stop();
> -
> - /* Make sure that we have a valid soft_margin */
> - if (hpwdt_change_timer(soft_margin))
> - hpwdt_change_timer(DEFAULT_MARGIN);
> + hpwdt_stop(&hpwdt_dev);
>
> /* Initialize NMI Decoding functionality */
> retval = hpwdt_init_nmi_decoding(dev);
> if (retval != 0)
> goto error_init_nmi_decoding;
>
> - retval = misc_register(&hpwdt_miscdev);
> + retval = watchdog_register_device(&hpwdt_dev);
> if (retval < 0) {
> - dev_warn(&dev->dev,
> - "Unable to register miscdev on minor=%d (err=%d).\n",
> - WATCHDOG_MINOR, retval);
> - goto error_misc_register;
> + dev_warn(&dev->dev, "Unable to register hpe watchdog (err=%d).\n", retval);
> + goto error_wd_register;
> + }
> +
> + watchdog_set_nowayout(&hpwdt_dev, nowayout);
> + if (watchdog_init_timeout(&hpwdt_dev, soft_margin, NULL)) {
> + dev_warn(&dev->dev, "Invalid soft_margin: %d. Using default\n", soft_margin);
> + soft_margin = DEFAULT_MARGIN;
> }

In this case watchdog_init_timout() will:
1) Check if soft_margin is valid
2) if not, keep hpwdt_dev.timout intact (which is already set in
declaration of hpwdt_dev)

So we could remove the condition and only keep
watchdog_init_timeout(&hpwdt_dev, soft_margin, NULL);


Also, we need to set an invalid initial value for soft_margin to make
the logic for watchdog_init_timeout work.

i.e
- static unsigned int soft_margin = DEFAULT_MARGIN; /* in seconds */
+ static unsigned int soft_margin;

>
> dev_info(&dev->dev, "HPE Watchdog Timer Driver: %s"
> ", timer margin: %d seconds (nowayout=%d).\n",
> - HPWDT_VERSION, soft_margin, nowayout);

print hpwdt_dev.timeout instead of soft_margin

> + HPWDT_VERSION, hpwdt_dev.timeout, nowayout);
> +
> return 0;
>
> -error_misc_register:
> +error_wd_register:
> hpwdt_exit_nmi_decoding();
> error_init_nmi_decoding:
> pci_iounmap(dev, pci_mem_addr);
> @@ -417,9 +273,9 @@ static int hpwdt_probe(struct pci_dev *dev, const struct pci_device_id *ent)
> static void hpwdt_exit(struct pci_dev *dev)
> {
> if (!nowayout)
> - hpwdt_stop();
> + hpwdt_stop(&hpwdt_dev);
>
> - misc_deregister(&hpwdt_miscdev);
> + watchdog_unregister_device(&hpwdt_dev);
> hpwdt_exit_nmi_decoding();
> pci_iounmap(dev, pci_mem_addr);
> pci_disable_device(dev);
> @@ -432,6 +288,25 @@ static struct pci_driver hpwdt_driver = {
> .remove = hpwdt_exit,
> };
>
> +
> +static const struct watchdog_ops hpwdt_ops = {
> + .owner = THIS_MODULE,
> + .start = hpwdt_start,
> + .stop = hpwdt_stop,
> + .ping = hpwdt_ping,
> + .set_timeout = hpwdt_settimeout,
> + .get_timeleft = hpwdt_gettimeleft,
> +};
> +
> +static struct watchdog_device hpwdt_dev = {
> + .info = &hpwdt_info,
> + .ops = &hpwdt_ops,
> + .min_timeout = 1,
> + .max_timeout = HPWDT_MAX_TIMER,
> + .timeout = DEFAULT_MARGIN,
> +};
> +
> +
> MODULE_AUTHOR("Jerry Hoemann");
> MODULE_DESCRIPTION("hpe watchdog driver");
> MODULE_LICENSE("GPL");
> --
> 2.13.6
>

Best regards
Marcus Folkesson
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