PCI: endpoint: functions: Add an EP function to test PCI

Adds a new endpoint function driver (to program the virtual test device)
making use of the EP-core library.

[bhelgaas: fold in pci_epf_test_probe() -ENOMEM test from Wei Yongjun
<[e-mail]>]
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>

drivers/pci/endpoint/Kconfig

···
 	   configure the endpoint function and used to bind the
 	   function with a endpoint controller.
 
+source "drivers/pci/endpoint/functions/Kconfig"
+
 endmenu

drivers/pci/endpoint/Makefile

···
 
 obj-$(CONFIG_PCI_ENDPOINT_CONFIGFS)	+= pci-ep-cfs.o
 obj-$(CONFIG_PCI_ENDPOINT)		+= pci-epc-core.o pci-epf-core.o\
-					   pci-epc-mem.o
+					   pci-epc-mem.o functions/

drivers/pci/endpoint/functions/Kconfig

···
+#
+# PCI Endpoint Functions
+#
+
+config PCI_EPF_TEST
+	tristate "PCI Endpoint Test driver"
+	depends on PCI_ENDPOINT
+	help
+	   Enable this configuration option to enable the test driver
+	   for PCI Endpoint.
+
+	   If in doubt, say "N" to disable Endpoint test driver.

drivers/pci/endpoint/functions/Makefile

···
+#
+# Makefile for PCI Endpoint Functions
+#
+
+obj-$(CONFIG_PCI_EPF_TEST)		+= pci-epf-test.o

drivers/pci/endpoint/functions/pci-epf-test.c

···
+/**
+ * Test driver to test endpoint functionality
+ *
+ * Copyright (C) 2017 Texas Instruments
+ * Author: Kishon Vijay Abraham I <[e-mail]>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 of
+ * the License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/crc32.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/pci_ids.h>
+#include <linux/random.h>
+
+#include <linux/pci-epc.h>
+#include <linux/pci-epf.h>
+#include <linux/pci_regs.h>
+
+#define COMMAND_RAISE_LEGACY_IRQ	BIT(0)
+#define COMMAND_RAISE_MSI_IRQ		BIT(1)
+#define MSI_NUMBER_SHIFT		2
+#define MSI_NUMBER_MASK			(0x3f << MSI_NUMBER_SHIFT)
+#define COMMAND_READ			BIT(8)
+#define COMMAND_WRITE			BIT(9)
+#define COMMAND_COPY			BIT(10)
+
+#define STATUS_READ_SUCCESS		BIT(0)
+#define STATUS_READ_FAIL		BIT(1)
+#define STATUS_WRITE_SUCCESS		BIT(2)
+#define STATUS_WRITE_FAIL		BIT(3)
+#define STATUS_COPY_SUCCESS		BIT(4)
+#define STATUS_COPY_FAIL		BIT(5)
+#define STATUS_IRQ_RAISED		BIT(6)
+#define STATUS_SRC_ADDR_INVALID		BIT(7)
+#define STATUS_DST_ADDR_INVALID		BIT(8)
+
+#define TIMER_RESOLUTION		1
+
+static struct workqueue_struct *kpcitest_workqueue;
+
+struct pci_epf_test {
+	void			*reg[6];
+	struct pci_epf		*epf;
+	struct delayed_work	cmd_handler;
+};
+
+struct pci_epf_test_reg {
+	u32	magic;
+	u32	command;
+	u32	status;
+	u64	src_addr;
+	u64	dst_addr;
+	u32	size;
+	u32	checksum;
+} __packed;
+
+static struct pci_epf_header test_header = {
+	.vendorid	= PCI_ANY_ID,
+	.deviceid	= PCI_ANY_ID,
+	.baseclass_code = PCI_CLASS_OTHERS,
+	.interrupt_pin	= PCI_INTERRUPT_INTA,
+};
+
+static int bar_size[] = { 512, 1024, 16384, 131072, 1048576 };
+
+static int pci_epf_test_copy(struct pci_epf_test *epf_test)
+{
+	int ret;
+	void __iomem *src_addr;
+	void __iomem *dst_addr;
+	phys_addr_t src_phys_addr;
+	phys_addr_t dst_phys_addr;
+	struct pci_epf *epf = epf_test->epf;
+	struct device *dev = &epf->dev;
+	struct pci_epc *epc = epf->epc;
+	struct pci_epf_test_reg *reg = epf_test->reg[0];
+
+	src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
+	if (!src_addr) {
+		dev_err(dev, "failed to allocate source address\n");
+		reg->status = STATUS_SRC_ADDR_INVALID;
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = pci_epc_map_addr(epc, src_phys_addr, reg->src_addr, reg->size);
+	if (ret) {
+		dev_err(dev, "failed to map source address\n");
+		reg->status = STATUS_SRC_ADDR_INVALID;
+		goto err_src_addr;
+	}
+
+	dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr, reg->size);
+	if (!dst_addr) {
+		dev_err(dev, "failed to allocate destination address\n");
+		reg->status = STATUS_DST_ADDR_INVALID;
+		ret = -ENOMEM;
+		goto err_src_map_addr;
+	}
+
+	ret = pci_epc_map_addr(epc, dst_phys_addr, reg->dst_addr, reg->size);
+	if (ret) {
+		dev_err(dev, "failed to map destination address\n");
+		reg->status = STATUS_DST_ADDR_INVALID;
+		goto err_dst_addr;
+	}
+
+	memcpy(dst_addr, src_addr, reg->size);
+
+	pci_epc_unmap_addr(epc, dst_phys_addr);
+
+err_dst_addr:
+	pci_epc_mem_free_addr(epc, dst_phys_addr, dst_addr, reg->size);
+
+err_src_map_addr:
+	pci_epc_unmap_addr(epc, src_phys_addr);
+
+err_src_addr:
+	pci_epc_mem_free_addr(epc, src_phys_addr, src_addr, reg->size);
+
+err:
+	return ret;
+}
+
+static int pci_epf_test_read(struct pci_epf_test *epf_test)
+{
+	int ret;
+	void __iomem *src_addr;
+	void *buf;
+	u32 crc32;
+	phys_addr_t phys_addr;
+	struct pci_epf *epf = epf_test->epf;
+	struct device *dev = &epf->dev;
+	struct pci_epc *epc = epf->epc;
+	struct pci_epf_test_reg *reg = epf_test->reg[0];
+
+	src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
+	if (!src_addr) {
+		dev_err(dev, "failed to allocate address\n");
+		reg->status = STATUS_SRC_ADDR_INVALID;
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = pci_epc_map_addr(epc, phys_addr, reg->src_addr, reg->size);
+	if (ret) {
+		dev_err(dev, "failed to map address\n");
+		reg->status = STATUS_SRC_ADDR_INVALID;
+		goto err_addr;
+	}
+
+	buf = kzalloc(reg->size, GFP_KERNEL);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto err_map_addr;
+	}
+
+	memcpy(buf, src_addr, reg->size);
+
+	crc32 = crc32_le(~0, buf, reg->size);
+	if (crc32 != reg->checksum)
+		ret = -EIO;
+
+	kfree(buf);
+
+err_map_addr:
+	pci_epc_unmap_addr(epc, phys_addr);
+
+err_addr:
+	pci_epc_mem_free_addr(epc, phys_addr, src_addr, reg->size);
+
+err:
+	return ret;
+}
+
+static int pci_epf_test_write(struct pci_epf_test *epf_test)
+{
+	int ret;
+	void __iomem *dst_addr;
+	void *buf;
+	phys_addr_t phys_addr;
+	struct pci_epf *epf = epf_test->epf;
+	struct device *dev = &epf->dev;
+	struct pci_epc *epc = epf->epc;
+	struct pci_epf_test_reg *reg = epf_test->reg[0];
+
+	dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
+	if (!dst_addr) {
+		dev_err(dev, "failed to allocate address\n");
+		reg->status = STATUS_DST_ADDR_INVALID;
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = pci_epc_map_addr(epc, phys_addr, reg->dst_addr, reg->size);
+	if (ret) {
+		dev_err(dev, "failed to map address\n");
+		reg->status = STATUS_DST_ADDR_INVALID;
+		goto err_addr;
+	}
+
+	buf = kzalloc(reg->size, GFP_KERNEL);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto err_map_addr;
+	}
+
+	get_random_bytes(buf, reg->size);
+	reg->checksum = crc32_le(~0, buf, reg->size);
+
+	memcpy(dst_addr, buf, reg->size);
+
+	/*
+	 * wait 1ms inorder for the write to complete. Without this delay L3
+	 * error in observed in the host system.
+	 */
+	mdelay(1);
+
+	kfree(buf);
+
+err_map_addr:
+	pci_epc_unmap_addr(epc, phys_addr);
+
+err_addr:
+	pci_epc_mem_free_addr(epc, phys_addr, dst_addr, reg->size);
+
+err:
+	return ret;
+}
+
+static void pci_epf_test_raise_irq(struct pci_epf_test *epf_test)
+{
+	u8 irq;
+	u8 msi_count;
+	struct pci_epf *epf = epf_test->epf;
+	struct pci_epc *epc = epf->epc;
+	struct pci_epf_test_reg *reg = epf_test->reg[0];
+
+	reg->status |= STATUS_IRQ_RAISED;
+	msi_count = pci_epc_get_msi(epc);
+	irq = (reg->command & MSI_NUMBER_MASK) >> MSI_NUMBER_SHIFT;
+	if (irq > msi_count || msi_count <= 0)
+		pci_epc_raise_irq(epc, PCI_EPC_IRQ_LEGACY, 0);
+	else
+		pci_epc_raise_irq(epc, PCI_EPC_IRQ_MSI, irq);
+}
+
+static void pci_epf_test_cmd_handler(struct work_struct *work)
+{
+	int ret;
+	u8 irq;
+	u8 msi_count;
+	struct pci_epf_test *epf_test = container_of(work, struct pci_epf_test,
+						     cmd_handler.work);
+	struct pci_epf *epf = epf_test->epf;
+	struct pci_epc *epc = epf->epc;
+	struct pci_epf_test_reg *reg = epf_test->reg[0];
+
+	if (!reg->command)
+		goto reset_handler;
+
+	if (reg->command & COMMAND_RAISE_LEGACY_IRQ) {
+		reg->status = STATUS_IRQ_RAISED;
+		pci_epc_raise_irq(epc, PCI_EPC_IRQ_LEGACY, 0);
+		goto reset_handler;
+	}
+
+	if (reg->command & COMMAND_WRITE) {
+		ret = pci_epf_test_write(epf_test);
+		if (ret)
+			reg->status |= STATUS_WRITE_FAIL;
+		else
+			reg->status |= STATUS_WRITE_SUCCESS;
+		pci_epf_test_raise_irq(epf_test);
+		goto reset_handler;
+	}
+
+	if (reg->command & COMMAND_READ) {
+		ret = pci_epf_test_read(epf_test);
+		if (!ret)
+			reg->status |= STATUS_READ_SUCCESS;
+		else
+			reg->status |= STATUS_READ_FAIL;
+		pci_epf_test_raise_irq(epf_test);
+		goto reset_handler;
+	}
+
+	if (reg->command & COMMAND_COPY) {
+		ret = pci_epf_test_copy(epf_test);
+		if (!ret)
+			reg->status |= STATUS_COPY_SUCCESS;
+		else
+			reg->status |= STATUS_COPY_FAIL;
+		pci_epf_test_raise_irq(epf_test);
+		goto reset_handler;
+	}
+
+	if (reg->command & COMMAND_RAISE_MSI_IRQ) {
+		msi_count = pci_epc_get_msi(epc);
+		irq = (reg->command & MSI_NUMBER_MASK) >> MSI_NUMBER_SHIFT;
+		if (irq > msi_count || msi_count <= 0)
+			goto reset_handler;
+		reg->status = STATUS_IRQ_RAISED;
+		pci_epc_raise_irq(epc, PCI_EPC_IRQ_MSI, irq);
+		goto reset_handler;
+	}
+
+reset_handler:
+	reg->command = 0;
+
+	queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler,
+			   msecs_to_jiffies(1));
+}
+
+static void pci_epf_test_linkup(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+
+	queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler,
+			   msecs_to_jiffies(1));
+}
+
+static void pci_epf_test_unbind(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+	struct pci_epc *epc = epf->epc;
+	int bar;
+
+	cancel_delayed_work(&epf_test->cmd_handler);
+	pci_epc_stop(epc);
+	for (bar = BAR_0; bar <= BAR_5; bar++) {
+		if (epf_test->reg[bar]) {
+			pci_epf_free_space(epf, epf_test->reg[bar], bar);
+			pci_epc_clear_bar(epc, bar);
+		}
+	}
+}
+
+static int pci_epf_test_set_bar(struct pci_epf *epf)
+{
+	int flags;
+	int bar;
+	int ret;
+	struct pci_epf_bar *epf_bar;
+	struct pci_epc *epc = epf->epc;
+	struct device *dev = &epf->dev;
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+
+	flags = PCI_BASE_ADDRESS_SPACE_MEMORY | PCI_BASE_ADDRESS_MEM_TYPE_32;
+	if (sizeof(dma_addr_t) == 0x8)
+		flags |= PCI_BASE_ADDRESS_MEM_TYPE_64;
+
+	for (bar = BAR_0; bar <= BAR_5; bar++) {
+		epf_bar = &epf->bar[bar];
+		ret = pci_epc_set_bar(epc, bar, epf_bar->phys_addr,
+				      epf_bar->size, flags);
+		if (ret) {
+			pci_epf_free_space(epf, epf_test->reg[bar], bar);
+			dev_err(dev, "failed to set BAR%d\n", bar);
+			if (bar == BAR_0)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int pci_epf_test_alloc_space(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+	struct device *dev = &epf->dev;
+	void *base;
+	int bar;
+
+	base = pci_epf_alloc_space(epf, sizeof(struct pci_epf_test_reg),
+				   BAR_0);
+	if (!base) {
+		dev_err(dev, "failed to allocated register space\n");
+		return -ENOMEM;
+	}
+	epf_test->reg[0] = base;
+
+	for (bar = BAR_1; bar <= BAR_5; bar++) {
+		base = pci_epf_alloc_space(epf, bar_size[bar - 1], bar);
+		if (!base)
+			dev_err(dev, "failed to allocate space for BAR%d\n",
+				bar);
+		epf_test->reg[bar] = base;
+	}
+
+	return 0;
+}
+
+static int pci_epf_test_bind(struct pci_epf *epf)
+{
+	int ret;
+	struct pci_epf_header *header = epf->header;
+	struct pci_epc *epc = epf->epc;
+	struct device *dev = &epf->dev;
+
+	if (WARN_ON_ONCE(!epc))
+		return -EINVAL;
+
+	ret = pci_epc_write_header(epc, header);
+	if (ret) {
+		dev_err(dev, "configuration header write failed\n");
+		return ret;
+	}
+
+	ret = pci_epf_test_alloc_space(epf);
+	if (ret)
+		return ret;
+
+	ret = pci_epf_test_set_bar(epf);
+	if (ret)
+		return ret;
+
+	ret = pci_epc_set_msi(epc, epf->msi_interrupts);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int pci_epf_test_probe(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test;
+	struct device *dev = &epf->dev;
+
+	epf_test = devm_kzalloc(dev, sizeof(*epf_test), GFP_KERNEL);
+	if (!epf_test)
+		return -ENOMEM;
+
+	epf->header = &test_header;
+	epf_test->epf = epf;
+
+	INIT_DELAYED_WORK(&epf_test->cmd_handler, pci_epf_test_cmd_handler);
+
+	epf_set_drvdata(epf, epf_test);
+	return 0;
+}
+
+static int pci_epf_test_remove(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+
+	kfree(epf_test);
+	return 0;
+}
+
+static struct pci_epf_ops ops = {
+	.unbind	= pci_epf_test_unbind,
+	.bind	= pci_epf_test_bind,
+	.linkup = pci_epf_test_linkup,
+};
+
+static const struct pci_epf_device_id pci_epf_test_ids[] = {
+	{
+		.name = "pci_epf_test",
+	},
+	{},
+};
+
+static struct pci_epf_driver test_driver = {
+	.driver.name	= "pci_epf_test",
+	.probe		= pci_epf_test_probe,
+	.remove		= pci_epf_test_remove,
+	.id_table	= pci_epf_test_ids,
+	.ops		= &ops,
+	.owner		= THIS_MODULE,
+};
+
+static int __init pci_epf_test_init(void)
+{
+	int ret;
+
+	kpcitest_workqueue = alloc_workqueue("kpcitest",
+					     WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
+	ret = pci_epf_register_driver(&test_driver);
+	if (ret) {
+		pr_err("failed to register pci epf test driver --> %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+module_init(pci_epf_test_init);
+
+static void __exit pci_epf_test_exit(void)
+{
+	pci_epf_unregister_driver(&test_driver);
+}
+module_exit(pci_epf_test_exit);
+
+MODULE_DESCRIPTION("PCI EPF TEST DRIVER");
+MODULE_AUTHOR("Kishon Vijay Abraham I <[e-mail]>");
+MODULE_LICENSE("GPL v2");