Hi Lorenzo, On 05/08/21 4:56 pm, Lorenzo Pieralisi wrote: > On Wed, Aug 04, 2021 at 07:32:44PM +0530, Kishon Vijay Abraham I wrote: >> Hi Lorenzo, >> >> On 03/08/21 3:28 pm, Lorenzo Pieralisi wrote: >>> On Tue, Aug 03, 2021 at 01:19:31PM +0530, Kishon Vijay Abraham I wrote: >>>> Allocation of IRQ vectors and requesting IRQ is done as part of >>>> PCITEST_SET_IRQTYPE. Do not request or allocate IRQs in probe for >>>> AM654 and J721E so that the user space test script has better control >>>> of the devices for which the IRQs are configured. Since certain user >>>> space scripts could rely on allocation of IRQ vectors during probe, >>>> remove allocation of IRQs only for TI's K3 platform. >>>> >>>> Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx> >>>> --- >>>> drivers/misc/pci_endpoint_test.c | 19 +++++++++++++------ >>>> 1 file changed, 13 insertions(+), 6 deletions(-) >>> >>> I don't claim to understand the inner details of the endpoint test >>> device but it looks like this approach should be redesigned. >>> >>> I don't believe using devices quirks is the best approach to >>> expose/remove a feature to userspace, this can soon become >>> unmaintenable. >>> >>> Maybe you can elaborate a bit more on what the real issue is please ? >> >> The actual reason for introducing this patch (affects only AM654 and >> J721E) is due to Errata ID #i2101 GIC: ITS Misbehavior >> (https://www.ti.com/lit/er/sprz455a/sprz455a.pdf). So if more than 5 >> devices use GIC ITS simultaneously, GIC fails to raise interrupts. >> >> Though this patch is not an actual workaround for the issue (the >> workaround is in GIC ITS driver provided in the errata document), it >> helps to keep testing PCIe RC/EP using pci-endpoint-test even when >> multiple pci-epf-test endpoint devices are connected (Normal test-setup >> having J721E-J721E back to back connection can support 21 pci-epf-test >> devices). So this patch lets user to individually enable interrupts for >> each of the devices and could disable after the interrupt test. >> >> Since pci_endpoint_test is used only for testing PCIE RC/EP >> communication and pci-endpoint-test has already implemented >> PCITEST_SET_IRQTYPE for the userspace to enable interrupt, tried to not >> enable the interrupts of all the devices by default in the probe (for >> AM654 and J721E where this errata applies). > > I understand - what I am asking is: > > is it possible, instead of applying this patch, to make > > pci_endpoint_test_alloc_irq_vectors() and pci_endpoint_test_request_irq() > > fail in the target platforms instead of preventing to call them ? hmm.. since both the platforms use GIC ITS it would need modifications in the irq-gic-v3-its.c driver. I could add the workaround mentioned in the errata document and send the patch for review to see what others think. Thanks, Kishon > > My worry is that you may end up with more corner cases in the future > and peppering code with is_() calls to work around them which does > not look right. > > Thanks, > Lorenzo > >> Thanks, >> Kishon >> >>> >>> Thanks, >>> Lorenzo >>> >>>> diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c >>>> index c7ee34013485..9740f2a0e7cd 100644 >>>> --- a/drivers/misc/pci_endpoint_test.c >>>> +++ b/drivers/misc/pci_endpoint_test.c >>>> @@ -79,6 +79,9 @@ >>>> #define PCI_DEVICE_ID_RENESAS_R8A774C0 0x002d >>>> #define PCI_DEVICE_ID_RENESAS_R8A774E1 0x0025 >>>> >>>> +#define is_j721e_pci_dev(pdev) \ >>>> + ((pdev)->device == PCI_DEVICE_ID_TI_J721E) >>>> + >>>> static DEFINE_IDA(pci_endpoint_test_ida); >>>> >>>> #define to_endpoint_test(priv) container_of((priv), struct pci_endpoint_test, \ >>>> @@ -810,9 +813,11 @@ static int pci_endpoint_test_probe(struct pci_dev *pdev, >>>> >>>> pci_set_master(pdev); >>>> >>>> - if (!pci_endpoint_test_alloc_irq_vectors(test, irq_type)) { >>>> - err = -EINVAL; >>>> - goto err_disable_irq; >>>> + if (!(is_am654_pci_dev(pdev) || is_j721e_pci_dev(pdev))) { >>>> + if (!pci_endpoint_test_alloc_irq_vectors(test, irq_type)) { >>>> + err = -EINVAL; >>>> + goto err_disable_irq; >>>> + } >>>> } >>>> >>>> for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) { >>>> @@ -850,9 +855,11 @@ static int pci_endpoint_test_probe(struct pci_dev *pdev, >>>> goto err_ida_remove; >>>> } >>>> >>>> - if (!pci_endpoint_test_request_irq(test)) { >>>> - err = -EINVAL; >>>> - goto err_kfree_test_name; >>>> + if (!(is_am654_pci_dev(pdev) || is_j721e_pci_dev(pdev))) { >>>> + if (!pci_endpoint_test_request_irq(test)) { >>>> + err = -EINVAL; >>>> + goto err_kfree_test_name; >>>> + } >>>> } >>>> >>>> misc_device = &test->miscdev; >>>> -- >>>> 2.17.1 >>>>
