linux-kernel - Re: [PATCH v4 3/5] watchdog: iTCO_wdt: Add PMC specific noreboot update api

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Message-ID: <CAENHMvNE_-uh9vWyiWmA5euc+nP5yCbZrYbmYfTqKUwqsSay6A@mail.gmail.com>
Date:   Sun, 2 Apr 2017 18:55:22 -0700
From:   Sathyanarayanan Kuppuswamy Natarajan <sathyaosid@...il.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        Andy Shevchenko <andy@...radead.org>,
        Zha Qipeng <qipeng.zha@...el.com>,
        "dvhart@...radead.org" <dvhart@...radead.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Wim Van Sebroeck <wim@...ana.be>,
        David Box <david.e.box@...ux.intel.com>,
        Rajneesh Bhardwaj <rajneesh.bhardwaj@...el.com>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-watchdog@...r.kernel.org
Subject: Re: [PATCH v4 3/5] watchdog: iTCO_wdt: Add PMC specific noreboot
 update api

Hi,

On Sun, Apr 2, 2017 at 7:04 AM, Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
> On Sat, Apr 1, 2017 at 2:27 AM, Kuppuswamy Sathyanarayanan
> <sathyanarayanan.kuppuswamy@...ux.intel.com> wrote:
>> In some SOCs, setting noreboot bit needs modification to
>
> SoCs.
>
> Perhaps you can create a wikipage to share with your team what style
> issues usually needs to be addressed.
> One of them is a proper capitalization in abbreviations / code names.
>
>> PMC GC registers. But not all PMC drivers allow other drivers
>> to memory map their GC region. This could create mem request
>> conflict in watchdog driver. So this patch adds facility to allow
>> PMC drivers to pass noreboot update function to watchdog
>> drivers via platform data.
>
>> --- a/drivers/watchdog/iTCO_wdt.c
>> +++ b/drivers/watchdog/iTCO_wdt.c
>> @@ -100,6 +100,8 @@ struct iTCO_wdt_private {
>>          */
>>         struct resource *gcs_pmc_res;
>>         unsigned long __iomem *gcs_pmc;
>
>> +       /* pmc specific api to update noreboot flag */
>
> PMC
> API
will fix in next version.
>
>> +       int (*update_noreboot_flag)(bool status);
>>         /* the lock for io operations */
>>         spinlock_t io_lock;
>>         /* the PCI-device */
>> @@ -176,9 +178,13 @@ static void iTCO_wdt_set_NO_REBOOT_bit(struct iTCO_wdt_private *p)
>>
>>         /* Set the NO_REBOOT bit: this disables reboots */
>>         if (p->iTCO_version >= 2) {
>> -               val32 = readl(p->gcs_pmc);
>> -               val32 |= no_reboot_bit(p);
>> -               writel(val32, p->gcs_pmc);
>> +               if (p->update_noreboot_flag)
>
>> +                       p->update_noreboot_flag(1);
>
> 1 -> true for sake of consistency.
ditto
>
>> +               else {
>> +                       val32 = readl(p->gcs_pmc);
>> +                       val32 |= no_reboot_bit(p);
>> +                       writel(val32, p->gcs_pmc);
>> +               }
>>         } else if (p->iTCO_version == 1) {
>>                 pci_read_config_dword(p->pci_dev, 0xd4, &val32);
>>                 val32 |= no_reboot_bit(p);
>> @@ -193,11 +199,14 @@ static int iTCO_wdt_unset_NO_REBOOT_bit(struct iTCO_wdt_private *p)
>>
>>         /* Unset the NO_REBOOT bit: this enables reboots */
>>         if (p->iTCO_version >= 2) {
>> -               val32 = readl(p->gcs_pmc);
>> -               val32 &= ~enable_bit;
>> -               writel(val32, p->gcs_pmc);
>> -
>> -               val32 = readl(p->gcs_pmc);
>> +               if (p->update_noreboot_flag)
>
>> +                       return p->update_noreboot_flag(0);
>
> 0 -> false.
ditto
>
>> +               else {
>
>> +                       val32 = readl(p->gcs_pmc);
>> +                       val32 &= ~enable_bit;
>> +                       writel(val32, p->gcs_pmc);
>> +                       val32 = readl(p->gcs_pmc);
>
> This and similar above code might be split to a helper and you may
> assign it once. In such case you will not need a special flag anymore.
>
> Helpers split might be done as a preparatory separate patch.
Yes, will create a patch for fixing it.
>
> --
> With Best Regards,
> Andy Shevchenko



-- 
--

Sathya