linux-kernel - Re: [PATCH v3 4/5] platform/x86: intel_pmc_ipc: Fix iTCO GCS memory mapping failure

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Date:   Fri, 31 Mar 2017 10:22:26 -0700
From:   sathyanarayanan kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Rajneesh Bhardwaj <rajneesh.bhardwaj@...el.com>
Cc:     andy@...radead.org, qipeng.zha@...el.com, dvhart@...radead.org,
        linux@...ck-us.net, wim@...ana.be, sathyaosid@...il.com,
        david.e.box@...ux.intel.com, platform-driver-x86@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org
Subject: Re: [PATCH v3 4/5] platform/x86: intel_pmc_ipc: Fix iTCO GCS memory
 mapping failure



On 03/31/2017 07:01 AM, Rajneesh Bhardwaj wrote:
> On Fri, Mar 17, 2017 at 07:06:21PM -0700, Kuppuswamy Sathyanarayanan wrote:
>> iTCO watchdog driver need access to PMC_CFG GCR register to modify
>> the no reboot setting. Currently, this is done by passing PMC_CFG reg
>> address as memory resource to watchdog driver and allowing it directly
>> modify the PMC_CFG register. But currently PMC driver also has
>> requirement to memory map the entire GCR register space in this driver.
>> This causes mem request failure in watchdog driver. So this patch fixes
>> this issue by adding api to update noreboot flag and passes them
>> to watchdog driver via platform data.
>>
>> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
>> ---
>>   drivers/platform/x86/intel_pmc_ipc.c | 20 ++++++++++----------
>>   1 file changed, 10 insertions(+), 10 deletions(-)
>>
>> Changes since v2:
>>   * Added support for update_noreboot_bit api.
>>
>> diff --git a/drivers/platform/x86/intel_pmc_ipc.c b/drivers/platform/x86/intel_pmc_ipc.c
>> index ea5579e..0c66c11 100644
>> --- a/drivers/platform/x86/intel_pmc_ipc.c
>> +++ b/drivers/platform/x86/intel_pmc_ipc.c
>> @@ -126,7 +126,6 @@ static struct intel_pmc_ipc_dev {
>>   	struct platform_device *tco_dev;
>>   
>>   	/* gcr */
>> -	resource_size_t gcr_base;
>>   	void __iomem *gcr_mem_base;
>>   	int gcr_size;
>>   	bool has_gcr_regs;
>> @@ -254,6 +253,15 @@ int intel_pmc_gcr_update(u32 offset, u32 mask, u32 val)
>>   }
>>   EXPORT_SYMBOL_GPL(intel_pmc_gcr_update);
>>   
>> +static int update_noreboot_bit(bool status)
>> +{
>> +	if (status)
>> +		return intel_pmc_gcr_update(PMC_GCR_PMC_CFG_REG, BIT(4),
>> +					    BIT(4));
>> +	else
>> +		return intel_pmc_gcr_update(PMC_GCR_PMC_CFG_REG, BIT(4), 0);
>> +}
>> +
> I think bit 4 will hold good only when TCO version is 3. What about the
> other cases? Tested it on APL and it worked fine.

Setting bit 4 will work for both version 3 and 5. Currently this driver 
only handles wdt device creation for APL platform. For APL, WDT version 
is 5 and hence this fix should work fine.

For other cases, currently iTCO_wdt driver still uses the memory mapped 
reboot setting.
>
>>   static int intel_pmc_ipc_check_status(void)
>>   {
>>   	int status;
>> @@ -571,15 +579,12 @@ static struct resource tco_res[] = {
>>   	{
>>   		.flags = IORESOURCE_IO,
>>   	},
>> -	/* GCS */
>> -	{
>> -		.flags = IORESOURCE_MEM,
>> -	},
>>   };
>>   
>>   static struct itco_wdt_platform_data tco_info = {
>>   	.name = "Apollo Lake SoC",
>>   	.version = 5,
>> +	.update_noreboot_flag = update_noreboot_bit,
>>   };
>>   
>>   #define TELEMETRY_RESOURCE_PUNIT_SSRAM	0
>> @@ -636,10 +641,6 @@ static int ipc_create_tco_device(void)
>>   	res->start = ipcdev.acpi_io_base + SMI_EN_OFFSET;
>>   	res->end = res->start + SMI_EN_SIZE - 1;
>>   
>> -	res = tco_res + TCO_RESOURCE_GCR_MEM;
>> -	res->start = ipcdev.gcr_base + TCO_PMC_OFFSET;
>> -	res->end = res->start + TCO_PMC_SIZE - 1;
>> -
>>   	pdev = platform_device_register_full(&pdevinfo);
>>   	if (IS_ERR(pdev))
>>   		return PTR_ERR(pdev);
>> @@ -801,7 +802,6 @@ static int ipc_plat_get_res(struct platform_device *pdev)
>>   	}
>>   	ipcdev.ipc_base = addr;
>>   
>> -	ipcdev.gcr_base = res->start + PLAT_RESOURCE_GCR_OFFSET;
>>   	ipcdev.gcr_mem_base = addr + PLAT_RESOURCE_GCR_OFFSET;
>>   	ipcdev.gcr_size = PLAT_RESOURCE_GCR_SIZE;
>>   	dev_info(&pdev->dev, "ipc res: %pR\n", res);
>> -- 
>> 2.7.4
>>

-- 
Sathyanarayanan Kuppuswamy
Android kernel developer