linux-kernel - Re: [PATCH RFC] watchdog: add a new driver for VIA chipsets

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Message-ID: <20111122173029.GA14349@pengutronix.de>
Date:	Tue, 22 Nov 2011 18:30:29 +0100
From:	Wolfram Sang <w.sang@...gutronix.de>
To:	Marc Vertes <marc.vertes@...fox.com>
Cc:	Wim@...r.kernel.org, wim@...ana.be, Welte@...r.kernel.org,
	Van@...r.kernel.org, Sebroeck@...r.kernel.org,
	linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
	HaraldWelte@...tech.com, Harald@...r.kernel.org
Subject: Re: [PATCH RFC] watchdog: add a new driver for VIA chipsets

On Tue, Nov 22, 2011 at 06:05:48PM +0100, Marc Vertes wrote:
> Wolfram Sang <w.sang@...gutronix.de> wrote:
> 
> > On Tue, Nov 22, 2011 at 12:17:13PM +0100, Marc Vertes wrote:
> > > Add a new driver for the hardware watchdog timer on VIA chipsets.
> > > Tested on a Artigo A1100, VX855 chipset.
> > > 
> > > Signed-off-by: Marc Vertes <marc.vertes@...fox.com>
> >
> > New watchdog drivers should use the framework. Have a look at
> > Documentation/watchdog/convert_drivers_to_kernel_api.txt for a guide. It
> > is mainly removing code, though.
> >
> Here it is:

Great, thanks.

> +static int wdt_start(struct watchdog_device *wdev)
> +{
> +	/* Nothing to do. The watchdog can only be started by the BIOS. */
> +	return 0;
> +}
> +
> +static int wdt_stop(struct watchdog_device *wdev)
> +{
> +	/* Nothing to do. The watchdog can not be stopped. */
> +	return 0;
> +}

Hmm, I'll leave this to Wim if it can stay like this (or if he wants a timer to
serve the non-stoppable watchdog or so).

> +static int __devinit wdt_probe(struct pci_dev *pdev,
> +			       const struct pci_device_id *ent)
> +{
> +	unsigned int mmio = 0;
> +	void __iomem *wdt_mem;
> +	int ret;
> +
> +	if (pci_enable_device(pdev)) {
> +		dev_err(&pdev->dev, "cannot enable PCI device\n");
> +		return -ENODEV;
> +	}
> +	pci_read_config_dword(pdev, VIA_WDT_MB_OFFSET, &mmio);
> +	dev_info(&pdev->dev, "VIA Chipset watchdog MMIO: %x\n", mmio);
> +	if (mmio == 0) {
> +		dev_err(&pdev->dev, "watchdog timer is not enabled in BIOS\n");
> +		return -ENODEV;
> +	}

What about

	if (mmio != 0) {
		dev_info("VIA Chipset...")
	} else {
		dev_err()
		return -ENODEV;
	}

to only have the needed printouts.

> +	wdt_mem = ioremap(mmio, 8);
> +	if (wdt_mem == NULL) {
> +		dev_err(&pdev->dev, "cannot remap VIA wdt mmio registers\n");
> +		return -ENODEV;
> +	}
> +	ret = watchdog_register_device(&wdt_dev);
> +	if (ret)
> +		return ret;

You need to iounmap in the error-case.

> +	watchdog_set_drvdata(&wdt_dev, wdt_mem);
> +	if (readl(wdt_mem) & VIA_WDT_FIRED) {
> +		wdt_dev.bootstatus |= WDIOF_CARDRESET;
> +		dev_notice(&pdev->dev, "restarted by expired watchdog\n");

Skip the printout. This can be detected using CARDRESET.

> +/*
> + * The driver has not been tested yet on CX700 and VX800.
> + */

Then, I'd rather skip this comment and the IDs. Or if you are sure enough it
works, leave them in ;) Best option would be testers showing up.

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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