usb: gadget: f_diag: Add support for configFS

This change adds APIs to allocate and instanciate
multi instance diag function driver using configFS.
Add an entry in kconfig to select diag driver for
configFS.

Change-Id: I428631dc63643eddb075a09d0e46e1a6b1117f0e
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>

3 files changed, 148 insertions, 46 deletions

diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 5cf6802b02ae..b5964662db93 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -211,6 +211,9 @@ config USB_F_AUDIO_SRC
 config USB_F_ACC
 	tristate
 
+config USB_F_DIAG
+	tristate
+
 choice
 	tristate "USB Gadget Drivers"
 	default USB_ETH
@@ -501,6 +504,14 @@ config USB_CONFIGFS_F_PRINTER
 	  For more information, see Documentation/usb/gadget_printer.txt
 	  which includes sample code for accessing the device file.
 
+config USB_CONFIGFS_F_DIAG
+	bool "USB Diag function"
+	select USB_F_DIAG
+	depends on USB_CONFIGFS
+	help
+	  Diag function driver enables support for Qualcomm diagnostics
+	  port over USB.
+
 source "drivers/usb/gadget/legacy/Kconfig"
 
 endchoice
diff --git a/drivers/usb/gadget/function/Makefile b/drivers/usb/gadget/function/Makefile
index 1cd544beef63..501254edd645 100644
--- a/drivers/usb/gadget/function/Makefile
+++ b/drivers/usb/gadget/function/Makefile
@@ -52,3 +52,5 @@ usb_f_audio_source-y            := f_audio_source.o
 obj-$(CONFIG_USB_F_AUDIO_SRC)   += usb_f_audio_source.o
 usb_f_accessory-y               := f_accessory.o
 obj-$(CONFIG_USB_F_ACC)         += usb_f_accessory.o
+usb_f_diag-y			:= f_diag.o
+obj-$(CONFIG_USB_F_DIAG)	+= usb_f_diag.o
diff --git a/drivers/usb/gadget/function/f_diag.c b/drivers/usb/gadget/function/f_diag.c
index edb3343f87e1..f89f81b4dfc9 100644
--- a/drivers/usb/gadget/function/f_diag.c
+++ b/drivers/usb/gadget/function/f_diag.c
@@ -30,6 +30,20 @@
 #include <linux/kmemleak.h>
 #include <linux/qcom/diag_dload.h>
 
+#define MAX_INST_NAME_LEN	40
+
+/* for configfs support */
+struct diag_opts {
+	struct usb_function_instance func_inst;
+	char *name;
+};
+
+static inline struct diag_opts *to_diag_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct diag_opts,
+			    func_inst.group);
+}
+
 static DEFINE_SPINLOCK(ch_lock);
 static LIST_HEAD(usb_diag_ch_list);
 
@@ -438,9 +452,7 @@ fail:
 
 }
 EXPORT_SYMBOL(usb_diag_alloc_req);
-#define DWC3_MAX_REQUEST_SIZE (1024 * 1024)
-#define CI_MAX_REQUEST_SIZE   (16 * 1024)
-/**
+#define DWC3_MAX_REQUEST_SIZE (16 * 1024 * 1024)
 /**
  * usb_diag_request_size - Max request size for controller
  * @ch: Channel handler
@@ -450,13 +462,7 @@ EXPORT_SYMBOL(usb_diag_alloc_req);
  */
 int usb_diag_request_size(struct usb_diag_ch *ch)
 {
-	struct diag_context *ctxt = ch->priv_usb;
-	struct usb_composite_dev *cdev = ctxt->cdev;
-
-	if (gadget_is_dwc3(cdev->gadget))
-		return DWC3_MAX_REQUEST_SIZE;
-	else
-		return CI_MAX_REQUEST_SIZE;
+	return DWC3_MAX_REQUEST_SIZE;
 }
 EXPORT_SYMBOL(usb_diag_request_size);
 
@@ -739,6 +745,8 @@ static int diag_function_bind(struct usb_configuration *c,
 	struct usb_ep *ep;
 	int status = -ENODEV;
 
+	ctxt->cdev = c->cdev;
+
 	intf_desc.bInterfaceNumber =  usb_interface_id(c, f);
 
 	ep = usb_ep_autoconfig(cdev->gadget, &fs_bulk_in_desc);
@@ -804,13 +812,13 @@ fail:
 
 }
 
-int diag_function_add(struct usb_configuration *c, const char *name)
+static struct diag_context *diag_context_init(const char *name)
 {
 	struct diag_context *dev;
 	struct usb_diag_ch *_ch;
-	int found = 0, ret;
+	int found = 0;
 
-	DBG(c->cdev, "diag_function_add\n");
+	pr_debug("%s\n", __func__);
 
 	list_for_each_entry(_ch, &usb_diag_ch_list, list) {
 		if (!strcmp(name, _ch->name)) {
@@ -819,13 +827,13 @@ int diag_function_add(struct usb_configuration *c, const char *name)
 		}
 	}
 	if (!found) {
-		ERROR(c->cdev, "unable to get diag usb channel\n");
-		return -ENODEV;
+		pr_err("%s: unable to get diag usb channel\n", __func__);
+		return ERR_PTR(-ENODEV);
 	}
 
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 	if (!dev)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	list_add_tail(&dev->list_item, &diag_dev_list);
 
@@ -837,7 +845,6 @@ int diag_function_add(struct usb_configuration *c, const char *name)
 	 */
 	dev->ch = _ch;
 
-	dev->cdev = c->cdev;
 	dev->function.name = _ch->name;
 	dev->function.fs_descriptors = fs_diag_desc;
 	dev->function.hs_descriptors = hs_diag_desc;
@@ -850,14 +857,7 @@ int diag_function_add(struct usb_configuration *c, const char *name)
 	INIT_LIST_HEAD(&dev->read_pool);
 	INIT_LIST_HEAD(&dev->write_pool);
 
-	ret = usb_add_function(c, &dev->function);
-	if (ret) {
-		INFO(c->cdev, "usb_add_function failed\n");
-		list_del(&dev->list_item);
-		kfree(dev);
-	}
-
-	return ret;
+	return dev;
 }
 
 #if defined(CONFIG_DEBUG_FS)
@@ -953,7 +953,111 @@ static inline void fdiag_debugfs_init(void) {}
 static inline void fdiag_debugfs_remove(void) {}
 #endif
 
-static void diag_cleanup(void)
+static void diag_opts_release(struct config_item *item)
+{
+	struct diag_opts *opts = to_diag_opts(item);
+
+	usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations diag_item_ops = {
+	.release	= diag_opts_release,
+};
+
+static struct config_item_type diag_func_type = {
+	.ct_item_ops	= &diag_item_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+static int diag_set_inst_name(struct usb_function_instance *fi,
+	const char *name)
+{
+	struct diag_opts *opts = container_of(fi, struct diag_opts, func_inst);
+	char *ptr;
+	int name_len;
+
+	name_len = strlen(name) + 1;
+	if (name_len > MAX_INST_NAME_LEN)
+		return -ENAMETOOLONG;
+
+	ptr = kstrndup(name, name_len, GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	opts->name = ptr;
+
+	return 0;
+}
+
+static void diag_free_inst(struct usb_function_instance *f)
+{
+	struct diag_opts *opts;
+
+	opts = container_of(f, struct diag_opts, func_inst);
+	kfree(opts->name);
+	kfree(opts);
+}
+
+static struct usb_function_instance *diag_alloc_inst(void)
+{
+	struct diag_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+
+	opts->func_inst.set_inst_name = diag_set_inst_name;
+	opts->func_inst.free_func_inst = diag_free_inst;
+	config_group_init_type_name(&opts->func_inst.group, "",
+				    &diag_func_type);
+
+	return &opts->func_inst;
+}
+
+static struct usb_function *diag_alloc(struct usb_function_instance *fi)
+{
+	struct diag_opts *opts;
+	struct diag_context *dev;
+
+	opts = container_of(fi, struct diag_opts, func_inst);
+
+	dev = diag_context_init(opts->name);
+	if (IS_ERR(dev))
+		return ERR_CAST(dev);
+
+	return &dev->function;
+}
+
+DECLARE_USB_FUNCTION(diag, diag_alloc_inst, diag_alloc);
+
+static int __init diag_init(void)
+{
+	struct device_node *np;
+	int ret;
+
+	INIT_LIST_HEAD(&diag_dev_list);
+
+	fdiag_debugfs_init();
+
+	ret = usb_function_register(&diagusb_func);
+	if (ret) {
+		pr_err("%s: failed to register diag %d\n", __func__, ret);
+		return ret;
+	}
+
+	np = of_find_compatible_node(NULL, NULL, "qcom,msm-imem-diag-dload");
+	if (!np)
+		np = of_find_compatible_node(NULL, NULL, "qcom,android-usb");
+
+	if (!np)
+		pr_warn("diag: failed to find diag_dload imem node\n");
+
+	diag_dload  = np ? of_iomap(np, 0) : NULL;
+
+	return ret;
+}
+
+static void __exit diag_exit(void)
 {
 	struct list_head *act, *tmp;
 	struct usb_diag_ch *_ch;
@@ -962,6 +1066,8 @@ static void diag_cleanup(void)
 	if (diag_dload)
 		iounmap(diag_dload);
 
+	usb_function_unregister(&diagusb_func);
+
 	fdiag_debugfs_remove();
 
 	list_for_each_safe(act, tmp, &usb_diag_ch_list) {
@@ -975,25 +1081,8 @@ static void diag_cleanup(void)
 		}
 		spin_unlock_irqrestore(&ch_lock, flags);
 	}
-}
-
-static int diag_setup(void)
-{
-	struct device_node *np;
-
-	INIT_LIST_HEAD(&diag_dev_list);
 
-	fdiag_debugfs_init();
-
-	np = of_find_compatible_node(NULL, NULL, "qcom,msm-imem-diag-dload");
-	if (!np)
-		np = of_find_compatible_node(NULL, NULL, "qcom,android-usb");
-
-	if (!np) {
-		pr_warn("diag: failed to find diag_dload imem node\n");
-		return 0;
-	}
-	diag_dload = of_iomap(np, 0);
-
-	return 0;
 }
+
+module_init(diag_init);
+module_exit(diag_exit);