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Date: Tue, 13 Feb 2018 10:05:17 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Marcus Folkesson <marcus.folkesson@...il.com>
Cc: Jerry Hoemann <jerry.hoemann@....com>, wim@...ux-watchdog.org,
linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
rwright@....com, maurice.a.saldivar@....com
Subject: Re: [PATCH v2 06/11] watchdog/hpwdt: Modify to use watchdog core.
On Mon, Feb 12, 2018 at 10:06:21AM +0100, Marcus Folkesson wrote:
> 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@....com>
>
I second Marcus' feedback.
Thanks,
Guenter
> 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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