USB: EHCI Debug Port Device Gadget
authorstephane duverger <stephane.duverger@gmail.com>
Mon, 12 Jul 2010 16:37:53 +0000 (18:37 +0200)
committerGreg Kroah-Hartman <gregkh@suse.de>
Tue, 10 Aug 2010 21:35:39 +0000 (14:35 -0700)
This is a patch that implements an USB EHCI Debug Device using the
Gadget API. This patch applies to a 2.6.35-rc3 kernel.

The gadget needs a compliant usb controller that forwards the
USB_DEVICE_DEBUG_MODE feature to its gadget.

The gadget provides two configuration modes, one that only printk() the
received data, and one that exposes a serial device to userland
(/dev/ttyGSxxx).

The gadget has been tested on an IGEPv2 board running a 2.6.35-rc1
kernel. The debug port was fed on the host side by a 2.6.34 kernel.

Signed-off-by: Stephane Duverger <stephane.duverger@gmail.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/gadget/Kconfig
drivers/usb/gadget/Makefile
drivers/usb/gadget/dbgp.c [new file with mode: 0644]

index dd3b2510185871a8e0f9998c270bfff5f7c575e7..cd27f9bde2c8b5ac84905c5ae2e2c7d00545fed6 100644 (file)
@@ -915,6 +915,34 @@ config USB_G_HID
          Say "y" to link the driver statically, or "m" to build a
          dynamically linked module called "g_hid".
 
+config USB_G_DBGP
+       tristate "EHCI Debug Device Gadget"
+       help
+         This gadget emulates an EHCI Debug device. This is useful when you want
+         to interact with an EHCI Debug Port.
+
+         Say "y" to link the driver statically, or "m" to build a
+         dynamically linked module called "g_dbgp".
+
+if USB_G_DBGP
+choice
+       prompt "EHCI Debug Device mode"
+       default USB_G_DBGP_SERIAL
+
+config USB_G_DBGP_PRINTK
+       depends on USB_G_DBGP
+       bool "printk"
+       help
+         Directly printk() received data. No interaction.
+
+config USB_G_DBGP_SERIAL
+       depends on USB_G_DBGP
+       bool "serial"
+       help
+         Userland can interact using /dev/ttyGSxxx.
+endchoice
+endif
+
 # put drivers that need isochronous transfer support (for audio
 # or video class gadget drivers), or specific hardware, here.
 config USB_G_WEBCAM
index 9bcde110feb1a3046e93176c2b65ac998f0ebfb7..397b892e90e2b69d0349bb278c80ea23a41e4078 100644 (file)
@@ -44,6 +44,7 @@ g_printer-objs                        := printer.o
 g_cdc-objs                     := cdc2.o
 g_multi-objs                   := multi.o
 g_hid-objs                     := hid.o
+g_dbgp-objs                    := dbgp.o
 g_nokia-objs                   := nokia.o
 g_webcam-objs                  := webcam.o
 
@@ -60,6 +61,7 @@ obj-$(CONFIG_USB_G_PRINTER)   += g_printer.o
 obj-$(CONFIG_USB_MIDI_GADGET)  += g_midi.o
 obj-$(CONFIG_USB_CDC_COMPOSITE) += g_cdc.o
 obj-$(CONFIG_USB_G_HID)                += g_hid.o
+obj-$(CONFIG_USB_G_DBGP)       += g_dbgp.o
 obj-$(CONFIG_USB_G_MULTI)      += g_multi.o
 obj-$(CONFIG_USB_G_NOKIA)      += g_nokia.o
 obj-$(CONFIG_USB_G_WEBCAM)     += g_webcam.o
diff --git a/drivers/usb/gadget/dbgp.c b/drivers/usb/gadget/dbgp.c
new file mode 100644 (file)
index 0000000..0ed50a2
--- /dev/null
@@ -0,0 +1,434 @@
+/*
+ * dbgp.c -- EHCI Debug Port device gadget
+ *
+ * Copyright (C) 2010 Stephane Duverger
+ *
+ * Released under the GPLv2.
+ *
+ */
+
+/* verbose messages */
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+
+/* See comments in "zero.c" */
+#include "epautoconf.c"
+
+#ifdef CONFIG_USB_G_DBGP_SERIAL
+#include "u_serial.c"
+#endif
+
+#define DRIVER_VENDOR_ID       0x0525 /* NetChip */
+#define DRIVER_PRODUCT_ID      0xc0de /* undefined */
+
+#define USB_DEBUG_MAX_PACKET_SIZE     8
+#define DBGP_REQ_EP0_LEN              128
+#define DBGP_REQ_LEN                  512
+
+static struct dbgp {
+       struct usb_gadget  *gadget;
+       struct usb_request *req;
+       struct usb_ep      *i_ep;
+       struct usb_ep      *o_ep;
+#ifdef CONFIG_USB_G_DBGP_SERIAL
+       struct gserial     *serial;
+#endif
+} dbgp;
+
+static struct usb_device_descriptor device_desc = {
+       .bLength = sizeof device_desc,
+       .bDescriptorType = USB_DT_DEVICE,
+       .bcdUSB = __constant_cpu_to_le16(0x0200),
+       .bDeviceClass = USB_CLASS_VENDOR_SPEC,
+       .idVendor = __constant_cpu_to_le16(DRIVER_VENDOR_ID),
+       .idProduct = __constant_cpu_to_le16(DRIVER_PRODUCT_ID),
+       .bNumConfigurations = 1,
+};
+
+static struct usb_debug_descriptor dbg_desc = {
+       .bLength = sizeof dbg_desc,
+       .bDescriptorType = USB_DT_DEBUG,
+};
+
+static struct usb_endpoint_descriptor i_desc = {
+       .bLength = USB_DT_ENDPOINT_SIZE,
+       .bDescriptorType = USB_DT_ENDPOINT,
+       .bmAttributes = USB_ENDPOINT_XFER_BULK,
+       .bEndpointAddress = USB_DIR_IN,
+};
+
+static struct usb_endpoint_descriptor o_desc = {
+       .bLength = USB_DT_ENDPOINT_SIZE,
+       .bDescriptorType = USB_DT_ENDPOINT,
+       .bmAttributes = USB_ENDPOINT_XFER_BULK,
+       .bEndpointAddress = USB_DIR_OUT,
+};
+
+#ifdef CONFIG_USB_G_DBGP_PRINTK
+static int dbgp_consume(char *buf, unsigned len)
+{
+       char c;
+
+       if (!len)
+               return 0;
+
+       c = buf[len-1];
+       if (c != 0)
+               buf[len-1] = 0;
+
+       printk(KERN_NOTICE "%s%c", buf, c);
+       return 0;
+}
+
+static void __disable_ep(struct usb_ep *ep)
+{
+       if (ep && ep->driver_data == dbgp.gadget) {
+               usb_ep_disable(ep);
+               ep->driver_data = NULL;
+       }
+}
+
+static void dbgp_disable_ep(void)
+{
+       __disable_ep(dbgp.i_ep);
+       __disable_ep(dbgp.o_ep);
+}
+
+static void dbgp_complete(struct usb_ep *ep, struct usb_request *req)
+{
+       int stp;
+       int err = 0;
+       int status = req->status;
+
+       if (ep == dbgp.i_ep) {
+               stp = 1;
+               goto fail;
+       }
+
+       if (status != 0) {
+               stp = 2;
+               goto release_req;
+       }
+
+       dbgp_consume(req->buf, req->actual);
+
+       req->length = DBGP_REQ_LEN;
+       err = usb_ep_queue(ep, req, GFP_ATOMIC);
+       if (err < 0) {
+               stp = 3;
+               goto release_req;
+       }
+
+       return;
+
+release_req:
+       kfree(req->buf);
+       usb_ep_free_request(dbgp.o_ep, req);
+       dbgp_disable_ep();
+fail:
+       dev_dbg(&dbgp.gadget->dev,
+               "complete: failure (%d:%d) ==> %d\n", stp, err, status);
+}
+
+static int dbgp_enable_ep_req(struct usb_ep *ep)
+{
+       int err, stp;
+       struct usb_request *req;
+
+       req = usb_ep_alloc_request(ep, GFP_KERNEL);
+       if (!req) {
+               err = -ENOMEM;
+               stp = 1;
+               goto fail_1;
+       }
+
+       req->buf = kmalloc(DBGP_REQ_LEN, GFP_KERNEL);
+       if (!req->buf) {
+               err = -ENOMEM;
+               stp = 2;
+               goto fail_2;
+       }
+
+       req->complete = dbgp_complete;
+       req->length = DBGP_REQ_LEN;
+       err = usb_ep_queue(ep, req, GFP_ATOMIC);
+       if (err < 0) {
+               stp = 3;
+               goto fail_3;
+       }
+
+       return 0;
+
+fail_3:
+       kfree(req->buf);
+fail_2:
+       usb_ep_free_request(dbgp.o_ep, req);
+fail_1:
+       dev_dbg(&dbgp.gadget->dev,
+               "enable ep req: failure (%d:%d)\n", stp, err);
+       return err;
+}
+
+static int __enable_ep(struct usb_ep *ep, struct usb_endpoint_descriptor *desc)
+{
+       int err = usb_ep_enable(ep, desc);
+       ep->driver_data = dbgp.gadget;
+       return err;
+}
+
+static int dbgp_enable_ep(void)
+{
+       int err, stp;
+
+       err = __enable_ep(dbgp.i_ep, &i_desc);
+       if (err < 0) {
+               stp = 1;
+               goto fail_1;
+       }
+
+       err = __enable_ep(dbgp.o_ep, &o_desc);
+       if (err < 0) {
+               stp = 2;
+               goto fail_2;
+       }
+
+       err = dbgp_enable_ep_req(dbgp.o_ep);
+       if (err < 0) {
+               stp = 3;
+               goto fail_3;
+       }
+
+       return 0;
+
+fail_3:
+       __disable_ep(dbgp.o_ep);
+fail_2:
+       __disable_ep(dbgp.i_ep);
+fail_1:
+       dev_dbg(&dbgp.gadget->dev, "enable ep: failure (%d:%d)\n", stp, err);
+       return err;
+}
+#endif
+
+static void dbgp_disconnect(struct usb_gadget *gadget)
+{
+#ifdef CONFIG_USB_G_DBGP_PRINTK
+       dbgp_disable_ep();
+#else
+       gserial_disconnect(dbgp.serial);
+#endif
+}
+
+static void dbgp_unbind(struct usb_gadget *gadget)
+{
+#ifdef CONFIG_USB_G_DBGP_SERIAL
+       kfree(dbgp.serial);
+#endif
+       if (dbgp.req) {
+               kfree(dbgp.req->buf);
+               usb_ep_free_request(gadget->ep0, dbgp.req);
+       }
+
+       gadget->ep0->driver_data = NULL;
+}
+
+static int __init dbgp_configure_endpoints(struct usb_gadget *gadget)
+{
+       int stp;
+
+       usb_ep_autoconfig_reset(gadget);
+
+       dbgp.i_ep = usb_ep_autoconfig(gadget, &i_desc);
+       if (!dbgp.i_ep) {
+               stp = 1;
+               goto fail_1;
+       }
+
+       dbgp.i_ep->driver_data = gadget;
+       i_desc.wMaxPacketSize =
+               __constant_cpu_to_le16(USB_DEBUG_MAX_PACKET_SIZE);
+
+       dbgp.o_ep = usb_ep_autoconfig(gadget, &o_desc);
+       if (!dbgp.o_ep) {
+               dbgp.i_ep->driver_data = NULL;
+               stp = 2;
+               goto fail_2;
+       }
+
+       dbgp.o_ep->driver_data = gadget;
+       o_desc.wMaxPacketSize =
+               __constant_cpu_to_le16(USB_DEBUG_MAX_PACKET_SIZE);
+
+       dbg_desc.bDebugInEndpoint = i_desc.bEndpointAddress & 0x7f;
+       dbg_desc.bDebugOutEndpoint = o_desc.bEndpointAddress & 0x7f;
+
+#ifdef CONFIG_USB_G_DBGP_SERIAL
+       dbgp.serial->in = dbgp.i_ep;
+       dbgp.serial->out = dbgp.o_ep;
+
+       dbgp.serial->in_desc = &i_desc;
+       dbgp.serial->out_desc = &o_desc;
+
+       if (gserial_setup(gadget, 1) < 0) {
+               stp = 3;
+               goto fail_3;
+       }
+
+       return 0;
+
+fail_3:
+       dbgp.o_ep->driver_data = NULL;
+#else
+       return 0;
+#endif
+fail_2:
+       dbgp.i_ep->driver_data = NULL;
+fail_1:
+       dev_dbg(&dbgp.gadget->dev, "ep config: failure (%d)\n", stp);
+       return -ENODEV;
+}
+
+static int __init dbgp_bind(struct usb_gadget *gadget)
+{
+       int err, stp;
+
+       dbgp.gadget = gadget;
+
+       dbgp.req = usb_ep_alloc_request(gadget->ep0, GFP_KERNEL);
+       if (!dbgp.req) {
+               err = -ENOMEM;
+               stp = 1;
+               goto fail;
+       }
+
+       dbgp.req->buf = kmalloc(DBGP_REQ_EP0_LEN, GFP_KERNEL);
+       if (!dbgp.req->buf) {
+               err = -ENOMEM;
+               stp = 2;
+               goto fail;
+       }
+
+       dbgp.req->length = DBGP_REQ_EP0_LEN;
+       gadget->ep0->driver_data = gadget;
+
+#ifdef CONFIG_USB_G_DBGP_SERIAL
+       dbgp.serial = kzalloc(sizeof(struct gserial), GFP_KERNEL);
+       if (!dbgp.serial) {
+               stp = 3;
+               err = -ENOMEM;
+               goto fail;
+       }
+#endif
+       err = dbgp_configure_endpoints(gadget);
+       if (err < 0) {
+               stp = 4;
+               goto fail;
+       }
+
+       dev_dbg(&dbgp.gadget->dev, "bind: success\n");
+       return 0;
+
+fail:
+       dev_dbg(&gadget->dev, "bind: failure (%d:%d)\n", stp, err);
+       dbgp_unbind(gadget);
+       return err;
+}
+
+static void dbgp_setup_complete(struct usb_ep *ep,
+                               struct usb_request *req)
+{
+       dev_dbg(&dbgp.gadget->dev, "setup complete: %d, %d/%d\n",
+               req->status, req->actual, req->length);
+}
+
+static int dbgp_setup(struct usb_gadget *gadget,
+                     const struct usb_ctrlrequest *ctrl)
+{
+       struct usb_request *req = dbgp.req;
+       u8 request = ctrl->bRequest;
+       u16 value = le16_to_cpu(ctrl->wValue);
+       u16 length = le16_to_cpu(ctrl->wLength);
+       int err = 0;
+       void *data;
+       u16 len;
+
+       gadget->ep0->driver_data = gadget;
+
+       if (request == USB_REQ_GET_DESCRIPTOR) {
+               switch (value>>8) {
+               case USB_DT_DEVICE:
+                       dev_dbg(&dbgp.gadget->dev, "setup: desc device\n");
+                       len = sizeof device_desc;
+                       data = &device_desc;
+                       break;
+               case USB_DT_DEBUG:
+                       dev_dbg(&dbgp.gadget->dev, "setup: desc debug\n");
+                       len = sizeof dbg_desc;
+                       data = &dbg_desc;
+                       break;
+               default:
+                       goto fail;
+               }
+       } else if (request == USB_REQ_SET_FEATURE &&
+                  value == USB_DEVICE_DEBUG_MODE) {
+               len = 0;
+               data = NULL;
+               dev_dbg(&dbgp.gadget->dev, "setup: feat debug\n");
+#ifdef CONFIG_USB_G_DBGP_PRINTK
+               err = dbgp_enable_ep();
+#else
+               err = gserial_connect(dbgp.serial, 0);
+#endif
+               if (err < 0)
+                       goto fail;
+       } else
+               goto fail;
+
+       if (len >= 0) {
+               req->length = min(length, len);
+               req->zero = len < req->length;
+               if (data && req->length)
+                       memcpy(req->buf, data, req->length);
+
+               req->complete = dbgp_setup_complete;
+               return usb_ep_queue(gadget->ep0, req, GFP_ATOMIC);
+       }
+
+fail:
+       dev_dbg(&dbgp.gadget->dev,
+               "setup: failure req %x v %x\n", request, value);
+       return err;
+}
+
+static struct usb_gadget_driver dbgp_driver = {
+       .function = "dbgp",
+       .speed = USB_SPEED_HIGH,
+       .bind = dbgp_bind,
+       .unbind = dbgp_unbind,
+       .setup = dbgp_setup,
+       .disconnect = dbgp_disconnect,
+       .driver = {
+               .owner = THIS_MODULE,
+               .name = "dbgp"
+       },
+};
+
+static int __init dbgp_init(void)
+{
+       return usb_gadget_register_driver(&dbgp_driver);
+}
+
+static void __exit dbgp_exit(void)
+{
+       usb_gadget_unregister_driver(&dbgp_driver);
+#ifdef CONFIG_USB_G_DBGP_SERIAL
+       gserial_cleanup();
+#endif
+}
+
+MODULE_AUTHOR("Stephane Duverger");
+MODULE_LICENSE("GPL");
+module_init(dbgp_init);
+module_exit(dbgp_exit);