misc: pci_endpoint_test: Gate doorbell test on dynamic inbound mapping

The doorbell test relies on the endpoint being able to update inbound
translations at runtime so the host can reach the doorbell target
through a BAR mapping.

If the endpoint does not advertise CAP_DYNAMIC_INBOUND_MAPPING, return
-EOPNOTSUPP from PCITEST_DOORBELL.

This avoids confusing failures in user space and kselftests when the
required capability is not available.

Suggested-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Link: https://patch.msgid.link/20260215150334.3391943-3-den@valinux.co.jp

diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c
index 74ab5b5b90110d9bfb229e01ffff8df67ea26704..93cd57d20881ff3037186b20f7f6a407d5e7d58d 100644 (file)
--- a/drivers/misc/pci_endpoint_test.c
+++ b/drivers/misc/pci_endpoint_test.c
@@ -84,6 +84,7 @@
 #define CAP_MSIX                               BIT(2)
 #define CAP_INTX                               BIT(3)
 #define CAP_SUBRANGE_MAPPING                   BIT(4)
+#define CAP_DYNAMIC_INBOUND_MAPPING            BIT(5)
 
 #define PCI_ENDPOINT_TEST_DB_BAR               0x34
 #define PCI_ENDPOINT_TEST_DB_OFFSET            0x38
@@ -1060,6 +1061,9 @@ static int pci_endpoint_test_doorbell(struct pci_endpoint_test *test)
        u32 addr;
        int left;
 
+       if (!(test->ep_caps & CAP_DYNAMIC_INBOUND_MAPPING))
+               return -EOPNOTSUPP;
+
        if (irq_type < PCITEST_IRQ_TYPE_INTX ||
            irq_type > PCITEST_IRQ_TYPE_MSIX) {
                dev_err(dev, "Invalid IRQ type\n");