[PATCH v3 5/6] misc: pci_endpoint_test: Add doorbell test case

[Frank Li]

Add three registers: PCIE_ENDPOINT_TEST_DB_BAR, PCIE_ENDPOINT_TEST_DB_ADDR,
and PCIE_ENDPOINT_TEST_DB_DATA.

Trigger the doorbell by writing data from PCI_ENDPOINT_TEST_DB_DATA to the
address provided by PCI_ENDPOINT_TEST_DB_ADDR and wait for endpoint
feedback.

Enable doorbell support only for PCI_DEVICE_ID_IMX8_DB, while other devices
keep the same behavior as before.

       EP side             RC with old driver      RC with new driver
PCI_DEVICE_ID_IMX8_DB          no probe              doorbell enabled
Other device ID             doorbell disabled*       doorbell disabled*

* Behavior remains unchanged.

Return failure if pcitest try to test doorbell bar.

Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
 drivers/misc/pci_endpoint_test.c | 60 ++++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/pcitest.h     |  1 +
 2 files changed, 61 insertions(+)

diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c
index 3aaaf47fa4ee2..a2b68c613c782 100644
--- a/drivers/misc/pci_endpoint_test.c
+++ b/drivers/misc/pci_endpoint_test.c
@@ -53,6 +53,7 @@
 #define STATUS_IRQ_RAISED			BIT(6)
 #define STATUS_SRC_ADDR_INVALID			BIT(7)
 #define STATUS_DST_ADDR_INVALID			BIT(8)
+#define STATUS_DOORBELL_SUCCESS			BIT(9)
 
 #define PCI_ENDPOINT_TEST_LOWER_SRC_ADDR	0x0c
 #define PCI_ENDPOINT_TEST_UPPER_SRC_ADDR	0x10
@@ -67,7 +68,12 @@
 #define PCI_ENDPOINT_TEST_IRQ_NUMBER		0x28
 
 #define PCI_ENDPOINT_TEST_FLAGS			0x2c
+#define PCI_ENDPOINT_TEST_DB_BAR		0x30
+#define PCI_ENDPOINT_TEST_DB_ADDR		0x34
+#define PCI_ENDPOINT_TEST_DB_DATA		0x38
+
 #define FLAG_USE_DMA				BIT(0)
+#define FLAG_SUPPORT_DOORBELL			BIT(1)
 
 #define PCI_DEVICE_ID_TI_AM654			0xb00c
 #define PCI_DEVICE_ID_TI_J7200			0xb00f
@@ -75,6 +81,7 @@
 #define PCI_DEVICE_ID_TI_J721S2		0xb013
 #define PCI_DEVICE_ID_LS1088A			0x80c0
 #define PCI_DEVICE_ID_IMX8			0x0808
+#define PCI_DEVICE_ID_IMX8_DB			0x080c
 
 #define is_am654_pci_dev(pdev)		\
 		((pdev)->device == PCI_DEVICE_ID_TI_AM654)
@@ -108,6 +115,7 @@ enum pci_barno {
 	BAR_3,
 	BAR_4,
 	BAR_5,
+	NO_BAR = -1,
 };
 
 struct pci_endpoint_test {
@@ -124,12 +132,14 @@ struct pci_endpoint_test {
 	enum pci_barno test_reg_bar;
 	size_t alignment;
 	const char *name;
+	bool support_db;
 };
 
 struct pci_endpoint_test_data {
 	enum pci_barno test_reg_bar;
 	size_t alignment;
 	int irq_type;
+	bool support_db;
 };
 
 static inline u32 pci_endpoint_test_readl(struct pci_endpoint_test *test,
@@ -746,6 +756,39 @@ static bool pci_endpoint_test_set_irq(struct pci_endpoint_test *test,
 	return false;
 }
 
+static bool pci_endpoint_test_doorbell(struct pci_endpoint_test *test)
+{
+	enum pci_barno bar;
+	u32 data, status;
+	u32 addr;
+
+	if (!test->support_db)
+		return false;
+
+	bar = pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_DB_BAR);
+	if (bar == NO_BAR)
+		return false;
+
+	data = pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_DB_DATA);
+	addr = pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_DB_ADDR);
+	bar = pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_DB_BAR);
+
+	pci_endpoint_test_writel(test, PCI_ENDPOINT_TEST_IRQ_TYPE, irq_type);
+	pci_endpoint_test_writel(test, PCI_ENDPOINT_TEST_IRQ_NUMBER, 1);
+
+	pci_endpoint_test_writel(test, PCI_ENDPOINT_TEST_STATUS, 0);
+
+	writel(data, test->bar[bar] + addr);
+
+	wait_for_completion_timeout(&test->irq_raised, msecs_to_jiffies(1000));
+
+	status = pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_STATUS);
+	if (status & STATUS_DOORBELL_SUCCESS)
+		return true;
+
+	return false;
+}
+
 static long pci_endpoint_test_ioctl(struct file *file, unsigned int cmd,
 				    unsigned long arg)
 {
@@ -762,6 +805,9 @@ static long pci_endpoint_test_ioctl(struct file *file, unsigned int cmd,
 	switch (cmd) {
 	case PCITEST_BAR:
 		bar = arg;
+		if (test->support_db &&
+		    bar == pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_DB_BAR))
+			goto ret;
 		if (bar > BAR_5)
 			goto ret;
 		if (is_am654_pci_dev(pdev) && bar == BAR_0)
@@ -793,6 +839,9 @@ static long pci_endpoint_test_ioctl(struct file *file, unsigned int cmd,
 	case PCITEST_CLEAR_IRQ:
 		ret = pci_endpoint_test_clear_irq(test);
 		break;
+	case PCITEST_DOORBELL:
+		ret = pci_endpoint_test_doorbell(test);
+		break;
 	}
 
 ret:
@@ -839,6 +888,7 @@ static int pci_endpoint_test_probe(struct pci_dev *pdev,
 		test_reg_bar = data->test_reg_bar;
 		test->test_reg_bar = test_reg_bar;
 		test->alignment = data->alignment;
+		test->support_db = data->support_db;
 		irq_type = data->irq_type;
 	}
 
@@ -986,6 +1036,13 @@ static const struct pci_endpoint_test_data default_data = {
 	.irq_type = IRQ_TYPE_MSI,
 };
 
+static const struct pci_endpoint_test_data default_data_db = {
+	.test_reg_bar = BAR_0,
+	.alignment = SZ_4K,
+	.irq_type = IRQ_TYPE_MSI,
+	.support_db = true,
+};
+
 static const struct pci_endpoint_test_data am654_data = {
 	.test_reg_bar = BAR_2,
 	.alignment = SZ_64K,
@@ -1017,6 +1074,9 @@ static const struct pci_device_id pci_endpoint_test_tbl[] = {
 	  .driver_data = (kernel_ulong_t)&default_data,
 	},
 	{ PCI_DEVICE(PCI_VENDOR_ID_FREESCALE, PCI_DEVICE_ID_IMX8),},
+	{ PCI_DEVICE(PCI_VENDOR_ID_FREESCALE, PCI_DEVICE_ID_IMX8_DB),
+	  .driver_data = (kernel_ulong_t)&default_data_db,
+	},
 	{ PCI_DEVICE(PCI_VENDOR_ID_FREESCALE, PCI_DEVICE_ID_LS1088A),
 	  .driver_data = (kernel_ulong_t)&default_data,
 	},
diff --git a/include/uapi/linux/pcitest.h b/include/uapi/linux/pcitest.h
index 94b46b043b536..06d9f548b510e 100644
--- a/include/uapi/linux/pcitest.h
+++ b/include/uapi/linux/pcitest.h
@@ -21,6 +21,7 @@
 #define PCITEST_SET_IRQTYPE	_IOW('P', 0x8, int)
 #define PCITEST_GET_IRQTYPE	_IO('P', 0x9)
 #define PCITEST_CLEAR_IRQ	_IO('P', 0x10)
+#define PCITEST_DOORBELL	_IO('P', 0x11)
 
 #define PCITEST_FLAGS_USE_DMA	0x00000001
 

-- 
2.34.1