linux-kernel - Re: [PATCH v1 1/1] platform/x86: intel_pmc

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Date:   Thu, 16 Mar 2017 14:15:44 -0700
From:   sathyanarayanan kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>,
        Rajneesh Bhardwaj <rajneesh.bhardwaj@...el.com>
Cc:     Andy Shevchenko <andy@...radead.org>,
        Zha Qipeng <qipeng.zha@...el.com>,
        "dvhart@...radead.org" <dvhart@...radead.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 1/1] platform/x86: intel_pmc_ipc: fix io mem mapping
 size

Hi Andy,


On 03/16/2017 01:12 PM, Andy Shevchenko wrote:
> On Thu, Mar 16, 2017 at 8:13 PM, Rajneesh Bhardwaj
> <rajneesh.bhardwaj@...el.com> wrote:
>> On Thu, Mar 16, 2017 at 06:05:39PM +0200, Andy Shevchenko wrote:
>>> On Thu, Mar 16, 2017 at 4:52 PM, Rajneesh Bhardwaj
>>> <rajneesh.bhardwaj@...el.com> wrote:
>>>> On Wed, Mar 15, 2017 at 08:32:53PM -0700, Kuppuswamy Sathyanarayanan wrote:
>>>>> Mapping entire GCR mem region in this driver creates
>>>>> mem region request conflict in sub devices that depend
>>>>> on PMC. This creates driver probe failure in devices like
>>>>> iTC0_wdt and telemetry device.
>>>> iTCO_WDT driver needs to check the BIT4 (NO_REBOOT) of PMC_CFG register
>>>> (Offset: 0x1008) and this falls in GCR space.
>>> Are we talking about ACPI-enabled platform?
>> IIUC, you are referring to WDT enumerated by ACPI tables (WDAT, WDRT etc) ?
>>
>> On APL/BXT i think we pass the resource mapping to iTCO_WDT driver since
>> acpi_has_watchdog provides the required protection. For non ACPI-enabled
>> platforms we have this issue since iTCO_WDT driver anyway tries resource
>> mapping when the iTCO_version >=2.
> And driver with necessary stuff should be already in upstream.
>
> https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git/tree/drivers/mfd/lpc_ich.c?h=watchdog-next#n552
>
> Or it's not enough?
Can this driver replace intel_pmc_ipc driver ? It seems to be missing 
IPC related APIs.

Regarding iTCO watchdog section, I think this driver also passes GCR 
region as memory resource to iTCO_WDT device.
>

-- 
Sathyanarayanan Kuppuswamy
Android kernel developer