Re: [PATCH V4 20/28] PCI: tegra: Use legacy IRQ for port service drivers

[Manikanta Maddireddy <mmaddireddy@nvidia.com>]

On 21-May-19 2:07 AM, Bjorn Helgaas wrote:
> On Thu, May 16, 2019 at 11:22:59AM +0530, Manikanta Maddireddy wrote:
>> Tegra signals PCIe services like AER, PME, etc. over legacy IRQ line.
>> By default, service drivers register interrupt routine over MSI IRQ line.
>> Use pcie_pme_disable_msi() function to disable MSI for service drivers.
> I think this device is not quite spec-compliant:
>
>   https://lore.kernel.org/linux-pci/20190520175729.GC49425@google.com/
>
> and you should work around this with a quirk that sets pdev->no_msi so
> we don't use MSI for it at all.

OK, I will update in next version. 

Manikanta

>
>> PME and AER interrupts registered to MSI without this change,
>> cat /proc/interrupts | grep -i pci
>> 36: 21 0 0 0 0 0 GICv2 104 Level       PCIE
>> 37: 35 0 0 0 0 0 GICv2 105 Level       Tegra PCIe MSI
>> 76: 0  0 0 0 0 0 Tegra PCIe MSI 0 Edge PCIe PME, aerdrv, PCIe BW notif
>>
>> PME and AER interrupts registered to legacy IRQ with this change,
>> cat /proc/interrupts | grep -i pci
>> 36: 33 0 0 0 0 0 GICv2 104 Level      PCIE, PCIe PME, aerdrv, PCIe BW notif
>> 37: 52 0 0 0 0 0 GICv2 105 Level      Tegra PCIe MSI
>>
>> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
>> Acked-by: Thierry Reding <treding@nvidia.com>
>> ---
>> V4: No change
>>
>> V3: Corrected typo in commit log
>>
>> V2: No change
>>
>>  drivers/pci/controller/pci-tegra.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
>> index ac57c5badd9b..0024bc42b400 100644
>> --- a/drivers/pci/controller/pci-tegra.c
>> +++ b/drivers/pci/controller/pci-tegra.c
>> @@ -41,6 +41,7 @@
>>  #include <soc/tegra/pmc.h>
>>  
>>  #include "../pci.h"
>> +#include "../pcie/portdrv.h"
>>  
>>  #define INT_PCI_MSI_NR (8 * 32)
>>  
>> @@ -2725,6 +2726,9 @@ static int tegra_pcie_probe(struct platform_device *pdev)
>>  		goto put_resources;
>>  	}
>>  
>> +	/* Switch to legacy IRQ for PCIe services like AER, PME*/
>> +	pcie_pme_disable_msi();
>> +
>>  	pm_runtime_enable(pcie->dev);
>>  	err = pm_runtime_get_sync(pcie->dev);
>>  	if (err) {
>> -- 
>> 2.17.1
>>