Re: [PATCH 2/3] watchdog: iTCO_wdt: Make ICH_RES_IO_SMI optional

Guenter Roeck
2020-02-25T14:37:12Z

On Tue, Feb 25, 2020 at 03:38:01PM +0300, Mika Westerberg wrote:
> The iTCO_wdt driver only needs ICH_RES_IO_SMI I/O resource when either
> turn_SMI_watchdog_clear_off module parameter is set to match ->iTCO_version
> (or higher), and when legacy iTCO_vendorsupport is set. Modify the driver
> so that ICH_RES_IO_SMI is optional if the two conditions are not met.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---
> drivers/watchdog/iTCO_wdt.c | 22 +++++++++++++---------
> 1 file changed, 13 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
> index 156360e37714..f1692452bc25 100644
> --- a/drivers/watchdog/iTCO_wdt.c
> +++ b/drivers/watchdog/iTCO_wdt.c
> @@ -460,7 +460,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
> return -ENODEV;
>
> p->smi_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_SMI);
> - if (!p->smi_res)
> + if (!p->smi_res && iTCO_vendorsupport)
> return -ENODEV;
>
> p->iTCO_version = pdata->version;
> @@ -492,15 +492,19 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
> /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
> p->update_no_reboot_bit(p->no_reboot_priv, true);
>
> - /* The TCO logic uses the TCO_EN bit in the SMI_EN register */
> - if (!devm_request_region(dev, p->smi_res->start,
> - resource_size(p->smi_res),
> - pdev->name)) {
> - pr_err("I/O address 0x%04llx already in use, device disabled\n",
> - (u64)SMI_EN(p));
> - return -EBUSY;
> - }
> if (turn_SMI_watchdog_clear_off >= p->iTCO_version) {
> + if (!p->smi_res) {
> + pr_err("SMI I/O resource is missing\n");
> + return -EINVAL;
> + }
> + /* The TCO logic uses the TCO_EN bit in the SMI_EN register */
> + if (!devm_request_region(dev, p->smi_res->start,
> + resource_size(p->smi_res),
> + pdev->name)) {
> + pr_err("I/O address 0x%04llx already in use, device disabled\n",
> + (u64)SMI_EN(p));
> + return -EBUSY;
> + }

The request_region call is also needed if iTCO_vendorsupport is true.
Well, not strictly speaking, I guess, but then one could argue that
it isn't needed at all.

In this context - looking into the vendorsupport code, I wonder if
it is time to retire it. Separate patch, of course, but still.
Any thoughts ?

Guenter