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 ? 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 > >>
