linux-kernel - [PATCH 2/3] misc: pci_endpoint

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Message-Id: <20230426203436.1277307-3-Frank.Li@nxp.com>
Date:   Wed, 26 Apr 2023 16:34:35 -0400
From:   Frank Li <Frank.Li@....com>
To:     tglx@...utronix.de
Cc:     aisheng.dong@....com, bhelgaas@...gle.com,
        devicetree@...r.kernel.org, festevam@...il.com, frank.li@....com,
        imx@...ts.linux.dev, jdmason@...zu.us, kernel@...gutronix.de,
        kishon@...com, krzysztof.kozlowski+dt@...aro.org, kw@...ux.com,
        linux-arm-kernel@...ts.infradead.org, linux-imx@....com,
        linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
        lorenzo.pieralisi@....com, lpieralisi@...nel.org,
        manivannan.sadhasivam@...aro.org, maz@...nel.org,
        ntb@...ts.linux.dev, peng.fan@....com, robh+dt@...nel.org,
        s.hauer@...gutronix.de, shawnguo@...nel.org
Subject: [PATCH 2/3] misc: pci_endpoint_test: Add doorbell test case

Reused flags as capability register in pci_endpoint_test struct to
support older driver versions. Save capability flags to 'cap' field
of struct pci_endpoint_test to prevent reading non-existent address.

Add three registers: PCIE_ENDPOINT_TEST_DB_BAR, PCIE_ENDPOINT_TEST_DB_ADDR,
PCIE_ENDPOINT_TEST_DB_DATA.

Write data from PCI_ENDPOINT_TEST_DB_DATA to address from
PCI_ENDPOINT_TEST_DB_ADDR to trigger doorbell and wait for remote
endpoint feedback.

Signed-off-by: Frank Li <Frank.Li@....com>
---
 drivers/misc/pci_endpoint_test.c | 41 ++++++++++++++++++++++++++++++++
 include/uapi/linux/pcitest.h     |  1 +
 2 files changed, 42 insertions(+)

diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c
index ed4d0ef5e5c3..3320a3334594 100644
--- a/drivers/misc/pci_endpoint_test.c
+++ b/drivers/misc/pci_endpoint_test.c
@@ -52,6 +52,7 @@
 #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
@@ -66,7 +67,12 @@
 #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
@@ -102,6 +108,7 @@ enum pci_barno {
 	BAR_3,
 	BAR_4,
 	BAR_5,
+	NO_BAR = -1,
 };
 
 struct pci_endpoint_test {
@@ -118,6 +125,7 @@ struct pci_endpoint_test {
 	enum pci_barno test_reg_bar;
 	size_t alignment;
 	const char *name;
+	u32 cap;
 };
 
 struct pci_endpoint_test_data {
@@ -713,6 +721,35 @@ 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;
+	u32 addr;
+
+	if (!(test->cap & FLAG_SUPPORT_DOORBELL))
+		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_STATUS, 0);
+	pci_endpoint_test_bar_writel(test, bar, addr, data);
+
+	wait_for_completion(&test->irq_raised);
+
+	data = pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_STATUS);
+	if (data & STATUS_DOORBELL_SUCCESS)
+		return true;
+
+	return false;
+}
+
 static long pci_endpoint_test_ioctl(struct file *file, unsigned int cmd,
 				    unsigned long arg)
 {
@@ -760,6 +797,9 @@ 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:
@@ -887,6 +927,7 @@ static int pci_endpoint_test_probe(struct pci_dev *pdev,
 	misc_device->parent = &pdev->dev;
 	misc_device->fops = &pci_endpoint_test_fops;
 
+	test->cap = pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_FLAGS);
 	err = misc_register(misc_device);
 	if (err) {
 		dev_err(dev, "Failed to register device\n");
diff --git a/include/uapi/linux/pcitest.h b/include/uapi/linux/pcitest.h
index f9c1af8d141b..479ca1aa3ae0 100644
--- a/include/uapi/linux/pcitest.h
+++ b/include/uapi/linux/pcitest.h
@@ -20,6 +20,7 @@
 #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