dm: usb: sandbox: Add a uclass for USB device emulation

With sandbox we want to be able to emulate USB devices so that we can test
the USB stack. Add a uclass to support this. It implements the same
operations as a normal USB device driver, but in this case passes them on
to an emulation driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Vasut <marex@denx.de>

7 files changed, 346 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 0f7d58388e..dc25f70ce0 100644
--- a/Makefile
+++ b/Makefile
@@ -651,6 +651,7 @@ libs-$(CONFIG_FMAN_ENET) += drivers/net/fm/
 libs-$(CONFIG_SYS_FSL_DDR) += drivers/ddr/fsl/
 libs-y += drivers/serial/
 libs-y += drivers/usb/dwc3/
+libs-y += drivers/usb/emul/
 libs-y += drivers/usb/eth/
 libs-y += drivers/usb/gadget/
 libs-y += drivers/usb/gadget/udc/
diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index a4414efab7..637ef3d567 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -51,6 +51,8 @@ config DM_USB
 
 source "drivers/usb/host/Kconfig"
 
+source "drivers/usb/emul/Kconfig"
+
 config USB_STORAGE
 	bool "USB Mass Storage support"
 	---help---
diff --git a/drivers/usb/emul/Kconfig b/drivers/usb/emul/Kconfig
new file mode 100644
index 0000000000..ae1ab23a3d
--- /dev/null
+++ b/drivers/usb/emul/Kconfig
@@ -0,0 +1,8 @@
+config USB_EMUL
+	bool "Support for USB device emulation"
+	depends on DM_USB && SANDBOX
+	help
+	  Since sandbox does not have access to a real USB bus, it is possible
+	  to use device emulators instead. This allows testing of the USB
+	  stack on sandbox without needing a real device, or any host machine
+	  USB resources.
diff --git a/drivers/usb/emul/Makefile b/drivers/usb/emul/Makefile
new file mode 100644
index 0000000000..f75bbd8eae
--- /dev/null
+++ b/drivers/usb/emul/Makefile
@@ -0,0 +1,8 @@
+#
+# (C) Copyright 2015 Google, Inc
+# Written by Simon Glass <sjg@chromium.org>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-$(CONFIG_USB_EMUL) += usb-emul-uclass.o
diff --git a/drivers/usb/emul/usb-emul-uclass.c b/drivers/usb/emul/usb-emul-uclass.c
new file mode 100644
index 0000000000..205f2c54df
--- /dev/null
+++ b/drivers/usb/emul/usb-emul-uclass.c
@@ -0,0 +1,263 @@
+/*
+ * (C) Copyright 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <usb.h>
+#include <dm/root.h>
+#include <dm/device-internal.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int copy_to_unicode(char *buff, int length, const char *str)
+{
+	int ptr;
+	int i;
+
+	if (length < 2)
+		return 0;
+	buff[1] = USB_DT_STRING;
+	for (ptr = 2, i = 0; ptr + 1 < length && *str; i++, ptr += 2) {
+		buff[ptr] = str[i];
+		buff[ptr + 1] = 0;
+	}
+	buff[0] = ptr;
+
+	return ptr;
+}
+
+static int usb_emul_get_string(struct usb_string *strings, int index,
+			       char *buff, int length)
+{
+	if (index == 0) {
+		char *desc = buff;
+
+		desc[0] = 4;
+		desc[1] = USB_DT_STRING;
+		desc[2] = 0x09;
+		desc[3] = 0x14;
+		return 4;
+	} else if (strings) {
+		struct usb_string *ptr;
+
+		for (ptr = strings; ptr->s; ptr++) {
+			if (ptr->id == index)
+				return copy_to_unicode(buff, length, ptr->s);
+		}
+	}
+
+	return -EINVAL;
+}
+
+static struct usb_generic_descriptor **find_descriptor(
+		struct usb_generic_descriptor **ptr, int type, int index)
+{
+	debug("%s: type=%x, index=%d\n", __func__, type, index);
+	for (; *ptr; ptr++) {
+		if ((*ptr)->bDescriptorType != type)
+			continue;
+		switch (type) {
+		case USB_DT_CONFIG: {
+			struct usb_config_descriptor *cdesc;
+
+			cdesc = (struct usb_config_descriptor *)*ptr;
+			if (cdesc && cdesc->bConfigurationValue == index)
+				return ptr;
+			break;
+		}
+		default:
+			return ptr;
+		}
+	}
+	debug("%s: config ptr=%p\n", __func__, *ptr);
+
+	return ptr;
+}
+
+static int usb_emul_get_descriptor(struct usb_dev_platdata *plat, int value,
+				   void *buffer, int length)
+{
+	struct usb_generic_descriptor **ptr;
+	int type = value >> 8;
+	int index = value & 0xff;
+	int upto, todo;
+
+	debug("%s: type=%d, index=%d, plat=%p\n", __func__, type, index, plat);
+	if (type == USB_DT_STRING) {
+		return usb_emul_get_string(plat->strings, index, buffer,
+					   length);
+	}
+
+	ptr = find_descriptor((struct usb_generic_descriptor **)plat->desc_list,
+			      type, index);
+	if (!ptr) {
+		debug("%s: Could not find descriptor type %d, index %d\n",
+		      __func__, type, index);
+		return -ENOENT;
+	}
+	for (upto = 0; *ptr && upto < length; ptr++, upto += todo) {
+		todo = min(length - upto, (int)(*ptr)->bLength);
+
+		memcpy(buffer + upto, *ptr, todo);
+	}
+
+	return upto ? upto : length ? -EIO : 0;
+}
+
+int usb_emul_find(struct udevice *bus, ulong pipe, struct udevice **emulp)
+{
+	int devnum = usb_pipedevice(pipe);
+	struct udevice *dev;
+	struct uclass *uc;
+	int ret;
+
+	*emulp = NULL;
+	ret = uclass_get(UCLASS_USB_EMUL, &uc);
+	if (ret)
+		return ret;
+	uclass_foreach_dev(dev, uc) {
+		struct usb_dev_platdata *udev = dev_get_parent_platdata(dev);
+
+		if (udev->devnum == devnum) {
+			debug("%s: Found emulator '%s', addr %d\n", __func__,
+			      dev->name, udev->devnum);
+			*emulp = dev;
+			return 0;
+		}
+	}
+
+	debug("%s: No emulator found, addr %d\n", __func__, devnum);
+	return -ENOENT;
+}
+
+int usb_emul_control(struct udevice *emul, struct usb_device *udev,
+		     unsigned long pipe, void *buffer, int length,
+		     struct devrequest *setup)
+{
+	struct dm_usb_ops *ops = usb_get_emul_ops(emul);
+	struct usb_dev_platdata *plat;
+	int ret;
+
+	/* We permit getting the descriptor before we are probed */
+	plat = dev_get_parent_platdata(emul);
+	if (!ops->control)
+		return -ENOSYS;
+	debug("%s: dev=%s\n", __func__, emul->name);
+	if (pipe == usb_rcvctrlpipe(udev, 0)) {
+		switch (setup->request) {
+		case USB_REQ_GET_DESCRIPTOR: {
+			return usb_emul_get_descriptor(plat, setup->value,
+						       buffer, length);
+		}
+		default:
+			ret = device_probe(emul);
+			if (ret)
+				return ret;
+			return ops->control(emul, udev, pipe, buffer, length,
+					    setup);
+		}
+	} else if (pipe == usb_snddefctrl(udev)) {
+		switch (setup->request) {
+		case USB_REQ_SET_ADDRESS:
+			debug("   ** set address %s %d\n", emul->name,
+			      setup->value);
+			plat->devnum = setup->value;
+			return 0;
+		default:
+			debug("requestsend =%x\n", setup->request);
+			break;
+		}
+	} else if (pipe == usb_sndctrlpipe(udev, 0)) {
+		switch (setup->request) {
+		case USB_REQ_SET_CONFIGURATION:
+			plat->configno = setup->value;
+			return 0;
+		default:
+			ret = device_probe(emul);
+			if (ret)
+				return ret;
+			return ops->control(emul, udev, pipe, buffer, length,
+					    setup);
+		}
+	}
+	debug("pipe=%lx\n", pipe);
+
+	return -EIO;
+}
+
+int usb_emul_bulk(struct udevice *emul, struct usb_device *udev,
+		  unsigned long pipe, void *buffer, int length)
+{
+	struct dm_usb_ops *ops = usb_get_emul_ops(emul);
+	int ret;
+
+	/* We permit getting the descriptor before we are probed */
+	if (!ops->bulk)
+		return -ENOSYS;
+	debug("%s: dev=%s\n", __func__, emul->name);
+	ret = device_probe(emul);
+	if (ret)
+		return ret;
+	return ops->bulk(emul, udev, pipe, buffer, length);
+}
+
+int usb_emul_setup_device(struct udevice *dev, int maxpacketsize,
+			  struct usb_string *strings, void **desc_list)
+{
+	struct usb_dev_platdata *plat = dev_get_parent_platdata(dev);
+	struct usb_generic_descriptor **ptr;
+	struct usb_config_descriptor *cdesc;
+	int upto;
+
+	plat->strings = strings;
+	plat->desc_list = (struct usb_generic_descriptor **)desc_list;
+
+	/* Fill in wTotalLength for each configuration descriptor */
+	ptr = plat->desc_list;
+	for (cdesc = NULL, upto = 0; *ptr; upto += (*ptr)->bLength, ptr++) {
+		debug("   - upto=%d, type=%d\n", upto, (*ptr)->bDescriptorType);
+		if ((*ptr)->bDescriptorType == USB_DT_CONFIG) {
+			if (cdesc) {
+				cdesc->wTotalLength = upto;
+				debug("%s: config %d length %d\n", __func__,
+				      cdesc->bConfigurationValue,
+				      cdesc->bLength);
+			}
+			cdesc = (struct usb_config_descriptor *)*ptr;
+			upto = 0;
+		}
+	}
+	if (cdesc) {
+		cdesc->wTotalLength = upto;
+		debug("%s: config %d length %d\n", __func__,
+		      cdesc->bConfigurationValue, cdesc->wTotalLength);
+	}
+
+	return 0;
+}
+
+int usb_emul_post_bind(struct udevice *dev)
+{
+	/* Scan the bus for devices */
+	return dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset, false);
+}
+
+void usb_emul_reset(struct udevice *dev)
+{
+	struct usb_dev_platdata *plat = dev_get_parent_platdata(dev);
+
+	plat->devnum = 0;
+	plat->configno = 0;
+}
+
+UCLASS_DRIVER(usb_emul) = {
+	.id		= UCLASS_USB_EMUL,
+	.name		= "usb_emul",
+	.post_bind	= usb_emul_post_bind,
+	.per_child_auto_alloc_size = sizeof(struct usb_device),
+	.per_child_platdata_auto_alloc_size = sizeof(struct usb_dev_platdata),
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 6fe3669968..3d62dbbb2a 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -21,6 +21,7 @@ enum uclass_id {
 	UCLASS_SPI_EMUL,	/* sandbox SPI device emulator */
 	UCLASS_I2C_EMUL,	/* sandbox I2C device emulator */
 	UCLASS_PCI_EMUL,	/* sandbox PCI device emulator */
+	UCLASS_USB_EMUL,	/* sandbox USB bus device emulator */
 	UCLASS_SIMPLE_BUS,
 
 	/* U-Boot uclasses start here */
diff --git a/include/usb.h b/include/usb.h
index 6db2140dd5..1984e8f590 100644
--- a/include/usb.h
+++ b/include/usb.h
@@ -179,7 +179,8 @@ enum usb_init_type {
 	defined(CONFIG_USB_BLACKFIN) || defined(CONFIG_USB_AM35X) || \
 	defined(CONFIG_USB_MUSB_DSPS) || defined(CONFIG_USB_MUSB_AM35X) || \
 	defined(CONFIG_USB_MUSB_OMAP2PLUS) || defined(CONFIG_USB_MUSB_SUNXI) || \
-	defined(CONFIG_USB_XHCI) || defined(CONFIG_USB_DWC2)
+	defined(CONFIG_USB_XHCI) || defined(CONFIG_USB_DWC2) || \
+	defined(CONFIG_USB_EMUL)
 
 int usb_lowlevel_init(int index, enum usb_init_type init, void **controller);
 int usb_lowlevel_stop(int index);
@@ -848,4 +849,65 @@ int usb_new_device(struct usb_device *dev);
 
 int usb_alloc_device(struct usb_device *dev);
 
+/**
+ * usb_emul_setup_device() - Set up a new USB device emulation
+ *
+ * This is normally called when a new emulation device is bound. It tells
+ * the USB emulation uclass about the features of the emulator.
+ *
+ * @dev:		Emulation device
+ * @maxpacketsize:	Maximum packet size (e.g. PACKET_SIZE_64)
+ * @strings:		List of USB string descriptors, terminated by a NULL
+ *			entry
+ * @desc_list:		List of points or USB descriptors, terminated by NULL.
+ *			The first entry must be struct usb_device_descriptor,
+ *			and others follow on after that.
+ * @return 0 if OK, -ve on error
+ */
+int usb_emul_setup_device(struct udevice *dev, int maxpacketsize,
+			  struct usb_string *strings, void **desc_list);
+
+/**
+ * usb_emul_control() - Send a control packet to an emulator
+ *
+ * @emul:	Emulator device
+ * @udev:	USB device (which the emulator is causing to appear)
+ * See struct dm_usb_ops for details on other parameters
+ * @return 0 if OK, -ve on error
+ */
+int usb_emul_control(struct udevice *emul, struct usb_device *udev,
+		     unsigned long pipe, void *buffer, int length,
+		     struct devrequest *setup);
+
+/**
+ * usb_emul_bulk() - Send a bulk packet to an emulator
+ *
+ * @emul:	Emulator device
+ * @udev:	USB device (which the emulator is causing to appear)
+ * See struct dm_usb_ops for details on other parameters
+ * @return 0 if OK, -ve on error
+ */
+int usb_emul_bulk(struct udevice *emul, struct usb_device *udev,
+		  unsigned long pipe, void *buffer, int length);
+
+/**
+ * usb_emul_find() - Find an emulator for a particular device
+ *
+ * Check @pipe to find a device number on bus @bus and return it.
+ *
+ * @bus:	USB bus (controller)
+ * @pipe:	Describes pipe being used, and includes the device number
+ * @emulp:	Returns pointer to emulator, or NULL if not found
+ * @return 0 if found, -ve on error
+ */
+int usb_emul_find(struct udevice *bus, ulong pipe, struct udevice **emulp);
+
+/**
+ * usb_emul_reset() - Reset all emulators ready for use
+ *
+ * Clear out any address information in the emulators and make then ready for
+ * a new USB scan
+ */
+void usb_emul_reset(struct udevice *dev);
+
 #endif /*_USB_H_ */