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Groups > linux.kernel > #1603616

Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping failure

From sathyanarayanan kuppuswamy <sathyanarayanan.kuppuswamy@linux.intel.com>
Newsgroups linux.kernel
Subject Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping failure
Date 2017-03-17 21:50 +0100
Message-ID <tm4kq-1GF-31@gated-at.bofh.it> (permalink)
References <tlOpk-6qV-11@gated-at.bofh.it> <tlOfE-6lR-19@gated-at.bofh.it> <tlYym-5OT-17@gated-at.bofh.it> <tm0qt-7b2-15@gated-at.bofh.it>
Organization Intel

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On 03/17/2017 06:40 AM, Guenter Roeck wrote:
> On 03/17/2017 04:43 AM, Rajneesh Bhardwaj wrote:
>> On Thu, Mar 16, 2017 at 05:41:35PM -0700, Kuppuswamy Sathyanarayanan 
>> wrote:
>>> Currently, iTCO watchdog driver uses memory map to access
>>> PMC_CFG GCR register. But the entire GCR address space is
>>> already mapped in intel_scu_ipc driver. So remapping the
>>
>> intel_pmc_ipc driver.
>>
>>> GCR register in this driver causes the mem request failure in
>>> iTCO_wdt probe function. This patch fixes this issue by
>>> using PMC GCR read/write API's to access PMC_CFG register.
>>>
>>> Signed-off-by: Kuppuswamy Sathyanarayanan 
>>> <sathyanarayanan.kuppuswamy@linux.intel.com>
>>> ---
>>>  drivers/watchdog/iTCO_wdt.c | 31 +++++++------------------------
>>>  1 file changed, 7 insertions(+), 24 deletions(-)
>>>
>>> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
>>> index 3d0abc0..31abfc5 100644
>>> --- a/drivers/watchdog/iTCO_wdt.c
>>> +++ b/drivers/watchdog/iTCO_wdt.c
>>> @@ -68,6 +68,8 @@
>>>  #include <linux/io.h>            /* For inb/outb/... */
>>>  #include <linux/platform_data/itco_wdt.h>
>>>
>>> +#include <asm/intel_pmc_ipc.h>
>>> +
>>>  #include "iTCO_vendor.h"
>>>
>>>  /* Address definitions for the TCO */
>>> @@ -94,12 +96,6 @@ struct iTCO_wdt_private {
>>>      unsigned int iTCO_version;
>>>      struct resource *tco_res;
>>>      struct resource *smi_res;
>>> -    /*
>>> -     * NO_REBOOT flag is Memory-Mapped GCS register bit 5 (TCO 
>>> version 2),
>>> -     * or memory-mapped PMC register bit 4 (TCO version 3).
>>> -     */
>>
>> Better to retain this comment elsewhere.
>>
>>> -    struct resource *gcs_pmc_res;
>>> -    unsigned long __iomem *gcs_pmc;
>>>      /* the lock for io operations */
>>>      spinlock_t io_lock;
>>>      /* the PCI-device */
>>> @@ -176,9 +172,9 @@ 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 = intel_pmc_gcr_read(PMC_GCR_PMC_CFG_REG);
>>
>> better to have protection and error handling, discussed in v2, 2/4.
>>
>> compiled and tested this on APL and i see iTCO_WDT driver loads fine. 
>> Since
>> it impacts core WDT functionality, need to be thoroughly tested on 
>> various
>> platforms.
>>
>
> I don't think I (or the watchdog mailing list) was copied on the 
> original patch.
Sorry. Its my mistake. I will fix it in next series update.
> Major immediate concern is that this introduces a dependency on 
> external code.
> The pmc_ipc driver's Kconfig entry states "This is not needed for PC-type
> machines". I don't know where the function is introduced, but I hope 
> this change
> does not require the pmc_ipc code to be present on such machines for 
> the watchdog
> to work. It would be bad if it does. If it doesn't, it appears that 
> the function
> should not be declared in asm/intel_pmc_ipc.h.
It should not create any compile time dependency with INTEL_PMC_IPC 
config option. If INTEL_PMC_IPC_CONFIG is disabled, we use
empty definitions for these calls defined in asm/intel_pmc_ipc.h

But iTCO_wdt driver already has runtime dependency with INTEL_PMIC_IPC 
if its version iTCO_version >= 2.

>
> Guenter
>
>

-- 
Sathyanarayanan Kuppuswamy
Android kernel developer

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Thread

[PATCH v1 1/1] platform/x86: intel_pmc_ipc: fix io mem mapping size Kuppuswamy Sathyanarayanan          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-16 04:40 +0100
  Re: [PATCH v1 1/1] platform/x86: intel_pmc_ipc: fix io mem mapping  size Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com> - 2017-03-16 16:00 +0100
    Re: [PATCH v1 1/1] platform/x86: intel_pmc_ipc: fix io mem mapping size Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-03-16 17:10 +0100
      Re: [PATCH v1 1/1] platform/x86: intel_pmc_ipc: fix io mem mapping  size Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com> - 2017-03-16 19:20 +0100
        Re: [PATCH v1 1/1] platform/x86: intel_pmc_ipc: fix io mem mapping size Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-03-16 21:20 +0100
          Re: [PATCH v1 1/1] platform/x86: intel_pmc_ipc: fix io mem mapping  size sathyanarayanan kuppuswamy          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-16 22:20 +0100
    Re: [PATCH v1 1/1] platform/x86: intel_pmc_ipc: fix io mem mapping  size sathyanarayanan kuppuswamy          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-16 20:00 +0100
      Re: [PATCH v1 1/1] platform/x86: intel_pmc_ipc: fix io mem mapping  size Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com> - 2017-03-16 20:30 +0100
        Re: [PATCH v1 1/1] platform/x86: intel_pmc_ipc: fix io mem mapping  size sathyanarayanan kuppuswamy          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-16 22:30 +0100
        [PATCH v2 2/4] platform/x86: intel_pmc_ipc: Add pmc gcr read/write api's Kuppuswamy Sathyanarayanan          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 01:50 +0100
          Re: [PATCH v2 2/4] platform/x86: intel_pmc_ipc: Add pmc gcr  read/write api's Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com> - 2017-03-17 12:30 +0100
            Re: [PATCH v2 2/4] platform/x86: intel_pmc_ipc: Add pmc gcr  read/write api's sathyanarayanan kuppuswamy          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 18:40 +0100
        [PATCH v2 4/4] platform/x86: intel_pmc_ipc: remove iTCO GCR mem resource Kuppuswamy Sathyanarayanan          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 01:50 +0100
          Re: [PATCH v2 4/4] platform/x86: intel_pmc_ipc: remove iTCO GCR mem  resource Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com> - 2017-03-17 12:50 +0100
        [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping failure Kuppuswamy Sathyanarayanan          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 01:50 +0100
          Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping  failure Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com> - 2017-03-17 12:50 +0100
            Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping  failure Guenter Roeck <linux@roeck-us.net> - 2017-03-17 14:50 +0100
              Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping  failure Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com> - 2017-03-17 15:10 +0100
              Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping failure Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-03-17 15:30 +0100
                Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping  failure sathyanarayanan kuppuswamy          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 18:50 +0100
                Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping failure Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-03-17 19:40 +0100
                Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping  failure sathyanarayanan kuppuswamy          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 20:00 +0100
              Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping  failure Guenter Roeck <linux@roeck-us.net> - 2017-03-17 19:00 +0100
                Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping  failure sathyanarayanan kuppuswamy          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 19:50 +0100
              Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping  failure sathyanarayanan kuppuswamy          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 21:50 +0100
            Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping  failure sathyanarayanan kuppuswamy          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 18:30 +0100
        [PATCH v2 1/4] platform/x86: intel_pmc_ipc: fix gcr offset Kuppuswamy Sathyanarayanan          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 02:00 +0100
          Re: [PATCH v2 1/4] platform/x86: intel_pmc_ipc: fix gcr offset Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com> - 2017-03-17 12:20 +0100
            Re: [PATCH v2 1/4] platform/x86: intel_pmc_ipc: fix gcr offset sathyanarayanan kuppuswamy          <sathyanarayanan.kuppuswamy@linux.intel.com> - 2017-03-17 18:20 +0100

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