[PATCH] PCI: endpoint: pci-epf-test: Add support for exposing EPC capabilities

[Niklas Cassel]

Currently, there is no way for the pci-endpoint-test driver (RC side),
to know which features the EPC supports.

Expose some of the EPC:s capabilities in the test_reg_bar, such that
the pci-endpoint-test driver can know if a feature (e.g. MSI-X or DMA)
is supported before attempting to test it.

Signed-off-by: Niklas Cassel <cassel@xxxxxxxxxx>
---
 drivers/misc/pci_endpoint_test.c              | 34 +++++++++++++++
 drivers/pci/endpoint/functions/pci-epf-test.c | 43 +++++++++++++++++++
 2 files changed, 77 insertions(+)

diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c
index 3aaaf47fa4ee..7eb045dc81b6 100644
--- a/drivers/misc/pci_endpoint_test.c
+++ b/drivers/misc/pci_endpoint_test.c
@@ -69,6 +69,20 @@
 #define PCI_ENDPOINT_TEST_FLAGS			0x2c
 #define FLAG_USE_DMA				BIT(0)
 
+#define CAPS_MAGIC				0x25ccf687
+#define PCI_ENDPOINT_TEST_CAPS_MAGIC		0x30
+#define PCI_ENDPOINT_TEST_CAPS_VERSION		0x34
+#define PCI_ENDPOINT_TEST_CAPS			0x38
+
+#define CAPS_MSI_SUPPORT		BIT(0)
+#define CAPS_MSIX_SUPPORT		BIT(1)
+#define CAPS_DMA_SUPPORT		BIT(2)
+#define CAPS_DMA_IS_PRIVATE		BIT(3) /* only valid if DMA_SUPPORT */
+#define CAPS_DOORBELL_SUPPORT		BIT(4)
+#define CAPS_DOORBELL_BAR_MASK		GENMASK(7, 5) /* only valid if DOORBELL_SUPPORT */
+#define CAPS_DOORBELL_BAR_SHIFT		5
+#define CAPS_DOORBELL_BAR(x)		(((x) & CAPS_DOORBELL_BAR_MASK) >> CAPS_DOORBELL_BAR_SHIFT)
+
 #define PCI_DEVICE_ID_TI_AM654			0xb00c
 #define PCI_DEVICE_ID_TI_J7200			0xb00f
 #define PCI_DEVICE_ID_TI_AM64			0xb010
@@ -805,6 +819,24 @@ static const struct file_operations pci_endpoint_test_fops = {
 	.unlocked_ioctl = pci_endpoint_test_ioctl,
 };
 
+static void pci_endpoint_get_caps(struct pci_endpoint_test *test)
+{
+	u32 caps_magic, caps;
+
+	/* check if endpoint has CAPS support */
+	caps_magic = pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_CAPS_MAGIC);
+	if (caps_magic != CAPS_MAGIC)
+		return;
+
+	caps = pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_CAPS);
+	pr_info("CAPS: MSI support: %u\n", (caps & CAPS_MSI_SUPPORT) ? 1 : 0);
+	pr_info("CAPS: MSI-X support: %u\n", (caps & CAPS_MSIX_SUPPORT) ? 1 : 0);
+	pr_info("CAPS: DMA support: %u\n", (caps & CAPS_DMA_SUPPORT) ? 1 : 0);
+	pr_info("CAPS: DMA is private: %u\n", (caps & CAPS_DMA_IS_PRIVATE) ? 1 : 0);
+	pr_info("CAPS: DOORBELL support: %u\n", (caps & CAPS_DOORBELL_SUPPORT) ? 1 : 0);
+	pr_info("CAPS: DOORBELL BAR: %lu\n", CAPS_DOORBELL_BAR(caps));
+}
+
 static int pci_endpoint_test_probe(struct pci_dev *pdev,
 				   const struct pci_device_id *ent)
 {
@@ -906,6 +938,8 @@ static int pci_endpoint_test_probe(struct pci_dev *pdev,
 		goto err_kfree_test_name;
 	}
 
+	pci_endpoint_get_caps(test);
+
 	misc_device = &test->miscdev;
 	misc_device->minor = MISC_DYNAMIC_MINOR;
 	misc_device->name = kstrdup(name, GFP_KERNEL);
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index a73bc0771d35..2dd90e2e8565 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -44,6 +44,18 @@
 
 #define TIMER_RESOLUTION		1
 
+#define CAPS_MAGIC			0x25ccf687
+#define CAPS_VERSION			0x1
+
+#define CAPS_MSI_SUPPORT		BIT(0)
+#define CAPS_MSIX_SUPPORT		BIT(1)
+#define CAPS_DMA_SUPPORT		BIT(2)
+#define CAPS_DMA_IS_PRIVATE		BIT(3) /* only valid if DMA_SUPPORT */
+#define CAPS_DOORBELL_SUPPORT		BIT(4)
+#define CAPS_DOORBELL_BAR_MASK		GENMASK(7, 5) /* only valid if DOORBELL_SUPPORT */
+#define CAPS_DOORBELL_BAR_SHIFT		5
+#define CAPS_DOORBELL_BAR(x)		(((x) & CAPS_DOORBELL_BAR_MASK) >> CAPS_DOORBELL_BAR_SHIFT)
+
 static struct workqueue_struct *kpcitest_workqueue;
 
 struct pci_epf_test {
@@ -74,6 +86,9 @@ struct pci_epf_test_reg {
 	u32	irq_type;
 	u32	irq_number;
 	u32	flags;
+	u32	caps_magic;
+	u32	caps_version;
+	u32	caps;
 } __packed;
 
 static struct pci_epf_header test_header = {
@@ -741,6 +756,32 @@ static void pci_epf_test_clear_bar(struct pci_epf *epf)
 	}
 }
 
+static void pci_epf_test_init_caps(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+	const struct pci_epc_features *epc_features = epf_test->epc_features;
+	enum pci_barno test_reg_bar = epf_test->test_reg_bar;
+	struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
+	u32 caps = 0;
+
+	reg->caps_magic = cpu_to_le32(CAPS_MAGIC);
+	reg->caps_version = cpu_to_le32(CAPS_VERSION);
+
+	if (epc_features->msi_capable)
+		caps |= CAPS_MSI_SUPPORT;
+
+	if (epc_features->msix_capable)
+		caps |= CAPS_MSIX_SUPPORT;
+
+	if (epf_test->dma_supported)
+		caps |= CAPS_DMA_SUPPORT;
+
+	if (epf_test->dma_private)
+		caps |= CAPS_DMA_IS_PRIVATE;
+
+	reg->caps = cpu_to_le64(caps);
+}
+
 static int pci_epf_test_epc_init(struct pci_epf *epf)
 {
 	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
@@ -765,6 +806,8 @@ static int pci_epf_test_epc_init(struct pci_epf *epf)
 		}
 	}
 
+	pci_epf_test_init_caps(epf);
+
 	ret = pci_epf_test_set_bar(epf);
 	if (ret)
 		return ret;
-- 
2.47.0