Re: [PATCH v3 12/26] PCI: keystone: Prevent ARM32 specific code to be compiled for ARM64

Kishon Vijay Abraham I
2019-04-12T11:31:08Z

Hi Lorenzo,

On 12/04/19 4:41 PM, Lorenzo Pieralisi wrote:
> On Fri, Apr 12, 2019 at 02:20:06PM +0530, Kishon Vijay Abraham I wrote:
>> Hi Lorenzo,
>>
>> On 11/04/19 8:33 PM, Lorenzo Pieralisi wrote:
>>> On Mon, Mar 25, 2019 at 03:09:33PM +0530, Kishon Vijay Abraham I wrote:
>>>> hook_fault_code is an ARM32 specific API for hooking into data abort.
>>>> Since pci-keystone.c will be used for AM65X platforms which is an
>>>> ARM64 platform,
>>>
>>> Hi Kishon,
>>>
>>> How is the problem plugged by the fault hook fixed on ARM64 ?
>>
>> At least in AM654 platform, I don't see a bus error when PCIe device
>> is not connected but returns 0xffffffff. So there is no necessary for
>> hook_fault_code in AM654 platform.
>
> That can't have much to do with ARM32<->ARM64, it is rather a platform
> integration issue AFAICS. Russell has a point, this has to be documented
> I can do it for you but I need additional information.

Right now only ARM32 exports hook_fault_code which was used by K2G (ARM32
platform) and since AM654 (ARM64 platform) uses the same driver, it'll result
in compilation error. Also AM654 doesn't require hook_fault_code (or something
similar) because it doesn't throw bus error on accessing PCIe address space
when PCI device is not connected).

Are you looking for some other information?

Thanks
Kishon
>
> Thanks,
> Lorenzo
>
>> Thanks
>> Kishon
>>
>>>
>>> Thanks,
>>> Lorenzo
>>>
>>>> allow hook_fault_code to be compiled only for ARM32.
>>>>
>>>> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
>>>> ---
>>>> drivers/pci/controller/dwc/pci-keystone.c | 4 ++++
>>>> 1 file changed, 4 insertions(+)
>>>>
>>>> diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
>>>> index dfe54553d832..93296d434f40 100644
>>>> --- a/drivers/pci/controller/dwc/pci-keystone.c
>>>> +++ b/drivers/pci/controller/dwc/pci-keystone.c
>>>> @@ -710,6 +710,7 @@ static int ks_pcie_config_legacy_irq(struct keystone_pcie *ks_pcie)
>>>> return ret;
>>>> }
>>>>
>>>> +#ifdef CONFIG_ARM
>>>> /*
>>>> * When a PCI device does not exist during config cycles, keystone host gets a
>>>> * bus error instead of returning 0xffffffff. This handler always returns 0
>>>> @@ -729,6 +730,7 @@ static int ks_pcie_fault(unsigned long addr, unsigned int fsr,
>>>>
>>>> return 0;
>>>> }
>>>> +#endif
>>>>
>>>> static int __init ks_pcie_init_id(struct keystone_pcie *ks_pcie)
>>>> {
>>>> @@ -778,12 +780,14 @@ static int __init ks_pcie_host_init(struct pcie_port *pp)
>>>> if (ret < 0)
>>>> return ret;
>>>>
>>>> +#ifdef CONFIG_ARM
>>>> /*
>>>> * PCIe access errors that result into OCP errors are caught by ARM as
>>>> * "External aborts"
>>>> */
>>>> hook_fault_code(17, ks_pcie_fault, SIGBUS, 0,
>>>> "Asynchronous external abort");
>>>> +#endif
>>>>
>>>> ks_pcie_start_link(pci);
>>>> dw_pcie_wait_for_link(pci);
>>>> --
>>>> 2.17.1
>>>>