PCI: endpoint: Introduce configfs entry for configuring EP functions

Introduce a new configfs entry to configure the EP function (like
configuring the standard configuration header entries) and to bind the EP
function with EP controller.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/endpoint/Kconfig

@@ -17,4 +17,13 @@ config PCI_ENDPOINT
 
 	   If in doubt, say "N" to disable Endpoint support.
 
+config PCI_ENDPOINT_CONFIGFS
+	bool "PCI Endpoint Configfs Support"
+	depends on PCI_ENDPOINT
+	select CONFIGFS_FS
+	help
+	   This will enable the configfs entry that can be used to
+	   configure the endpoint function and used to bind the
+	   function with a endpoint controller.
+
 endmenu

drivers/pci/endpoint/Makefile

@@ -2,5 +2,6 @@
 # Makefile for PCI Endpoint Support
 #
 
+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

drivers/pci/endpoint/pci-ep-cfs.c

+/**
+ * configfs to configure the PCI endpoint
+ *
+ * Copyright (C) 2017 Texas Instruments
+ * Author: Kishon Vijay Abraham I <kishon@ti.com>
+ *
+ * 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/module.h>
+#include <linux/slab.h>
+
+#include <linux/pci-epc.h>
+#include <linux/pci-epf.h>
+#include <linux/pci-ep-cfs.h>
+
+static struct config_group *functions_group;
+static struct config_group *controllers_group;
+
+struct pci_epf_group {
+	struct config_group group;
+	struct pci_epf *epf;
+};
+
+struct pci_epc_group {
+	struct config_group group;
+	struct pci_epc *epc;
+	bool start;
+	unsigned long function_num_map;
+};
+
+static inline struct pci_epf_group *to_pci_epf_group(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct pci_epf_group, group);
+}
+
+static inline struct pci_epc_group *to_pci_epc_group(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct pci_epc_group, group);
+}
+
+static ssize_t pci_epc_start_store(struct config_item *item, const char *page,
+				   size_t len)
+{
+	int ret;
+	bool start;
+	struct pci_epc *epc;
+	struct pci_epc_group *epc_group = to_pci_epc_group(item);
+
+	epc = epc_group->epc;
+
+	ret = kstrtobool(page, &start);
+	if (ret)
+		return ret;
+
+	if (!start) {
+		pci_epc_stop(epc);
+		return len;
+	}
+
+	ret = pci_epc_start(epc);
+	if (ret) {
+		dev_err(&epc->dev, "failed to start endpoint controller\n");
+		return -EINVAL;
+	}
+
+	epc_group->start = start;
+
+	return len;
+}
+
+static ssize_t pci_epc_start_show(struct config_item *item, char *page)
+{
+	return sprintf(page, "%d\n",
+		       to_pci_epc_group(item)->start);
+}
+
+CONFIGFS_ATTR(pci_epc_, start);
+
+static struct configfs_attribute *pci_epc_attrs[] = {
+	&pci_epc_attr_start,
+	NULL,
+};
+
+static int pci_epc_epf_link(struct config_item *epc_item,
+			    struct config_item *epf_item)
+{
+	int ret;
+	u32 func_no = 0;
+	struct pci_epc *epc;
+	struct pci_epf *epf;
+	struct pci_epf_group *epf_group = to_pci_epf_group(epf_item);
+	struct pci_epc_group *epc_group = to_pci_epc_group(epc_item);
+
+	epc = epc_group->epc;
+	epf = epf_group->epf;
+	ret = pci_epc_add_epf(epc, epf);
+	if (ret)
+		goto err_add_epf;
+
+	func_no = find_first_zero_bit(&epc_group->function_num_map,
+				      sizeof(epc_group->function_num_map));
+	set_bit(func_no, &epc_group->function_num_map);
+	epf->func_no = func_no;
+
+	ret = pci_epf_bind(epf);
+	if (ret)
+		goto err_epf_bind;
+
+	return 0;
+
+err_epf_bind:
+	pci_epc_remove_epf(epc, epf);
+
+err_add_epf:
+	clear_bit(func_no, &epc_group->function_num_map);
+
+	return ret;
+}
+
+static void pci_epc_epf_unlink(struct config_item *epc_item,
+			       struct config_item *epf_item)
+{
+	struct pci_epc *epc;
+	struct pci_epf *epf;
+	struct pci_epf_group *epf_group = to_pci_epf_group(epf_item);
+	struct pci_epc_group *epc_group = to_pci_epc_group(epc_item);
+
+	WARN_ON_ONCE(epc_group->start);
+
+	epc = epc_group->epc;
+	epf = epf_group->epf;
+	clear_bit(epf->func_no, &epc_group->function_num_map);
+	pci_epf_unbind(epf);
+	pci_epc_remove_epf(epc, epf);
+}
+
+static struct configfs_item_operations pci_epc_item_ops = {
+	.allow_link	= pci_epc_epf_link,
+	.drop_link	= pci_epc_epf_unlink,
+};
+
+static struct config_item_type pci_epc_type = {
+	.ct_item_ops	= &pci_epc_item_ops,
+	.ct_attrs	= pci_epc_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+struct config_group *pci_ep_cfs_add_epc_group(const char *name)
+{
+	int ret;
+	struct pci_epc *epc;
+	struct config_group *group;
+	struct pci_epc_group *epc_group;
+
+	epc_group = kzalloc(sizeof(*epc_group), GFP_KERNEL);
+	if (!epc_group) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	group = &epc_group->group;
+
+	config_group_init_type_name(group, name, &pci_epc_type);
+	ret = configfs_register_group(controllers_group, group);
+	if (ret) {
+		pr_err("failed to register configfs group for %s\n", name);
+		goto err_register_group;
+	}
+
+	epc = pci_epc_get(name);
+	if (IS_ERR(epc)) {
+		ret = PTR_ERR(epc);
+		goto err_epc_get;
+	}
+
+	epc_group->epc = epc;
+
+	return group;
+
+err_epc_get:
+	configfs_unregister_group(group);
+
+err_register_group:
+	kfree(epc_group);
+
+err:
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(pci_ep_cfs_add_epc_group);
+
+void pci_ep_cfs_remove_epc_group(struct config_group *group)
+{
+	struct pci_epc_group *epc_group;
+
+	if (!group)
+		return;
+
+	epc_group = container_of(group, struct pci_epc_group, group);
+	pci_epc_put(epc_group->epc);
+	configfs_unregister_group(&epc_group->group);
+	kfree(epc_group);
+}
+EXPORT_SYMBOL(pci_ep_cfs_remove_epc_group);
+
+#define PCI_EPF_HEADER_R(_name)						       \
+static ssize_t pci_epf_##_name##_show(struct config_item *item,	char *page)    \
+{									       \
+	struct pci_epf *epf = to_pci_epf_group(item)->epf;		       \
+	if (WARN_ON_ONCE(!epf->header))					       \
+		return -EINVAL;						       \
+	return sprintf(page, "0x%04x\n", epf->header->_name);		       \
+}
+
+#define PCI_EPF_HEADER_W_u32(_name)					       \
+static ssize_t pci_epf_##_name##_store(struct config_item *item,	       \
+				       const char *page, size_t len)	       \
+{									       \
+	u32 val;							       \
+	int ret;							       \
+	struct pci_epf *epf = to_pci_epf_group(item)->epf;		       \
+	if (WARN_ON_ONCE(!epf->header))					       \
+		return -EINVAL;						       \
+	ret = kstrtou32(page, 0, &val);					       \
+	if (ret)							       \
+		return ret;						       \
+	epf->header->_name = val;					       \
+	return len;							       \
+}
+
+#define PCI_EPF_HEADER_W_u16(_name)					       \
+static ssize_t pci_epf_##_name##_store(struct config_item *item,	       \
+				       const char *page, size_t len)	       \
+{									       \
+	u16 val;							       \
+	int ret;							       \
+	struct pci_epf *epf = to_pci_epf_group(item)->epf;		       \
+	if (WARN_ON_ONCE(!epf->header))					       \
+		return -EINVAL;						       \
+	ret = kstrtou16(page, 0, &val);					       \
+	if (ret)							       \
+		return ret;						       \
+	epf->header->_name = val;					       \
+	return len;							       \
+}
+
+#define PCI_EPF_HEADER_W_u8(_name)					       \
+static ssize_t pci_epf_##_name##_store(struct config_item *item,	       \
+				       const char *page, size_t len)	       \
+{									       \
+	u8 val;								       \
+	int ret;							       \
+	struct pci_epf *epf = to_pci_epf_group(item)->epf;		       \
+	if (WARN_ON_ONCE(!epf->header))					       \
+		return -EINVAL;						       \
+	ret = kstrtou8(page, 0, &val);					       \
+	if (ret)							       \
+		return ret;						       \
+	epf->header->_name = val;					       \
+	return len;							       \
+}
+
+static ssize_t pci_epf_msi_interrupts_store(struct config_item *item,
+					    const char *page, size_t len)
+{
+	u8 val;
+	int ret;
+
+	ret = kstrtou8(page, 0, &val);
+	if (ret)
+		return ret;
+
+	to_pci_epf_group(item)->epf->msi_interrupts = val;
+
+	return len;
+}
+
+static ssize_t pci_epf_msi_interrupts_show(struct config_item *item,
+					   char *page)
+{
+	return sprintf(page, "%d\n",
+		       to_pci_epf_group(item)->epf->msi_interrupts);
+}
+
+PCI_EPF_HEADER_R(vendorid)
+PCI_EPF_HEADER_W_u16(vendorid)
+
+PCI_EPF_HEADER_R(deviceid)
+PCI_EPF_HEADER_W_u16(deviceid)
+
+PCI_EPF_HEADER_R(revid)
+PCI_EPF_HEADER_W_u8(revid)
+
+PCI_EPF_HEADER_R(progif_code)
+PCI_EPF_HEADER_W_u8(progif_code)
+
+PCI_EPF_HEADER_R(subclass_code)
+PCI_EPF_HEADER_W_u8(subclass_code)
+
+PCI_EPF_HEADER_R(baseclass_code)
+PCI_EPF_HEADER_W_u8(baseclass_code)
+
+PCI_EPF_HEADER_R(cache_line_size)
+PCI_EPF_HEADER_W_u8(cache_line_size)
+
+PCI_EPF_HEADER_R(subsys_vendor_id)
+PCI_EPF_HEADER_W_u16(subsys_vendor_id)
+
+PCI_EPF_HEADER_R(subsys_id)
+PCI_EPF_HEADER_W_u16(subsys_id)
+
+PCI_EPF_HEADER_R(interrupt_pin)
+PCI_EPF_HEADER_W_u8(interrupt_pin)
+
+CONFIGFS_ATTR(pci_epf_, vendorid);
+CONFIGFS_ATTR(pci_epf_, deviceid);
+CONFIGFS_ATTR(pci_epf_, revid);
+CONFIGFS_ATTR(pci_epf_, progif_code);
+CONFIGFS_ATTR(pci_epf_, subclass_code);
+CONFIGFS_ATTR(pci_epf_, baseclass_code);
+CONFIGFS_ATTR(pci_epf_, cache_line_size);
+CONFIGFS_ATTR(pci_epf_, subsys_vendor_id);
+CONFIGFS_ATTR(pci_epf_, subsys_id);
+CONFIGFS_ATTR(pci_epf_, interrupt_pin);
+CONFIGFS_ATTR(pci_epf_, msi_interrupts);
+
+static struct configfs_attribute *pci_epf_attrs[] = {
+	&pci_epf_attr_vendorid,
+	&pci_epf_attr_deviceid,
+	&pci_epf_attr_revid,
+	&pci_epf_attr_progif_code,
+	&pci_epf_attr_subclass_code,
+	&pci_epf_attr_baseclass_code,
+	&pci_epf_attr_cache_line_size,
+	&pci_epf_attr_subsys_vendor_id,
+	&pci_epf_attr_subsys_id,
+	&pci_epf_attr_interrupt_pin,
+	&pci_epf_attr_msi_interrupts,
+	NULL,
+};
+
+static void pci_epf_release(struct config_item *item)
+{
+	struct pci_epf_group *epf_group = to_pci_epf_group(item);
+
+	pci_epf_destroy(epf_group->epf);
+	kfree(epf_group);
+}
+
+static struct configfs_item_operations pci_epf_ops = {
+	.release		= pci_epf_release,
+};
+
+static struct config_item_type pci_epf_type = {
+	.ct_item_ops	= &pci_epf_ops,
+	.ct_attrs	= pci_epf_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group *pci_epf_make(struct config_group *group,
+					 const char *name)
+{
+	struct pci_epf_group *epf_group;
+	struct pci_epf *epf;
+
+	epf_group = kzalloc(sizeof(*epf_group), GFP_KERNEL);
+	if (!epf_group)
+		return ERR_PTR(-ENOMEM);
+
+	config_group_init_type_name(&epf_group->group, name, &pci_epf_type);
+
+	epf = pci_epf_create(group->cg_item.ci_name);
+	if (IS_ERR(epf)) {
+		pr_err("failed to create endpoint function device\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	epf_group->epf = epf;
+
+	return &epf_group->group;
+}
+
+static void pci_epf_drop(struct config_group *group, struct config_item *item)
+{
+	config_item_put(item);
+}
+
+static struct configfs_group_operations pci_epf_group_ops = {
+	.make_group     = &pci_epf_make,
+	.drop_item      = &pci_epf_drop,
+};
+
+static struct config_item_type pci_epf_group_type = {
+	.ct_group_ops	= &pci_epf_group_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+struct config_group *pci_ep_cfs_add_epf_group(const char *name)
+{
+	struct config_group *group;
+
+	group = configfs_register_default_group(functions_group, name,
+						&pci_epf_group_type);
+	if (IS_ERR(group))
+		pr_err("failed to register configfs group for %s function\n",
+		       name);
+
+	return group;
+}
+EXPORT_SYMBOL(pci_ep_cfs_add_epf_group);
+
+void pci_ep_cfs_remove_epf_group(struct config_group *group)
+{
+	if (IS_ERR_OR_NULL(group))
+		return;
+
+	configfs_unregister_default_group(group);
+}
+EXPORT_SYMBOL(pci_ep_cfs_remove_epf_group);
+
+static struct config_item_type pci_functions_type = {
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_item_type pci_controllers_type = {
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_item_type pci_ep_type = {
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct configfs_subsystem pci_ep_cfs_subsys = {
+	.su_group = {
+		.cg_item = {
+			.ci_namebuf = "pci_ep",
+			.ci_type = &pci_ep_type,
+		},
+	},
+	.su_mutex = __MUTEX_INITIALIZER(pci_ep_cfs_subsys.su_mutex),
+};
+
+static int __init pci_ep_cfs_init(void)
+{
+	int ret;
+	struct config_group *root = &pci_ep_cfs_subsys.su_group;
+
+	config_group_init(root);
+
+	ret = configfs_register_subsystem(&pci_ep_cfs_subsys);
+	if (ret) {
+		pr_err("Error %d while registering subsystem %s\n",
+		       ret, root->cg_item.ci_namebuf);
+		goto err;
+	}
+
+	functions_group = configfs_register_default_group(root, "functions",
+							  &pci_functions_type);
+	if (IS_ERR(functions_group)) {
+		ret = PTR_ERR(functions_group);
+		pr_err("Error %d while registering functions group\n",
+		       ret);
+		goto err_functions_group;
+	}
+
+	controllers_group =
+		configfs_register_default_group(root, "controllers",
+						&pci_controllers_type);
+	if (IS_ERR(controllers_group)) {
+		ret = PTR_ERR(controllers_group);
+		pr_err("Error %d while registering controllers group\n",
+		       ret);
+		goto err_controllers_group;
+	}
+
+	return 0;
+
+err_controllers_group:
+	configfs_unregister_default_group(functions_group);
+
+err_functions_group:
+	configfs_unregister_subsystem(&pci_ep_cfs_subsys);
+
+err:
+	return ret;
+}
+module_init(pci_ep_cfs_init);
+
+static void __exit pci_ep_cfs_exit(void)
+{
+	configfs_unregister_default_group(controllers_group);
+	configfs_unregister_default_group(functions_group);
+	configfs_unregister_subsystem(&pci_ep_cfs_subsys);
+}
+module_exit(pci_ep_cfs_exit);
+
+MODULE_DESCRIPTION("PCI EP CONFIGFS");
+MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
+MODULE_LICENSE("GPL v2");

include/linux/pci-ep-cfs.h

+/**
+ * PCI Endpoint ConfigFS header file
+ *
+ * Copyright (C) 2017 Texas Instruments
+ * Author: Kishon Vijay Abraham I <kishon@ti.com>
+ *
+ * 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.
+ */
+
+#ifndef __LINUX_PCI_EP_CFS_H
+#define __LINUX_PCI_EP_CFS_H
+
+#include <linux/configfs.h>
+
+#ifdef CONFIG_PCI_ENDPOINT_CONFIGFS
+struct config_group *pci_ep_cfs_add_epc_group(const char *name);
+void pci_ep_cfs_remove_epc_group(struct config_group *group);
+struct config_group *pci_ep_cfs_add_epf_group(const char *name);
+void pci_ep_cfs_remove_epf_group(struct config_group *group);
+#else
+static inline struct config_group *pci_ep_cfs_add_epc_group(const char *name)
+{
+	return 0;
+}
+
+static inline void pci_ep_cfs_remove_epc_group(struct config_group *group)
+{
+}
+
+static inline struct config_group *pci_ep_cfs_add_epf_group(const char *name)
+{
+	return 0;
+}
+
+static inline void pci_ep_cfs_remove_epf_group(struct config_group *group)
+{
+}
+#endif
+#endif /* __LINUX_PCI_EP_CFS_H */