Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2046 insertions, 0 deletions

diff --git a/drivers/net/wireless/zydas/zd1211rw/zd_usb.c b/drivers/net/wireless/zydas/zd1211rw/zd_usb.c
new file mode 100644
index 000000000..66367ab7e
--- /dev/null
+++ b/drivers/net/wireless/zydas/zd1211rw/zd_usb.c
@@ -0,0 +1,2046 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* ZD1211 USB-WLAN driver for Linux
+ *
+ * Copyright (C) 2005-2007 Ulrich Kunitz <kune@deine-taler.de>
+ * Copyright (C) 2006-2007 Daniel Drake <dsd@gentoo.org>
+ * Copyright (C) 2006-2007 Michael Wu <flamingice@sourmilk.net>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/firmware.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+#include <linux/usb.h>
+#include <linux/workqueue.h>
+#include <linux/module.h>
+#include <net/mac80211.h>
+#include <asm/unaligned.h>
+
+#include "zd_def.h"
+#include "zd_mac.h"
+#include "zd_usb.h"
+
+static const struct usb_device_id usb_ids[] = {
+	/* ZD1211 */
+	{ USB_DEVICE(0x0105, 0x145f), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0586, 0x3401), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0586, 0x3402), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0586, 0x3407), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0586, 0x3409), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x079b, 0x004a), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x07b8, 0x6001), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0ace, 0x1211), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0ace, 0xa211), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0b05, 0x170c), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0b3b, 0x1630), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0b3b, 0x5630), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0df6, 0x9071), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x0df6, 0x9075), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x126f, 0xa006), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x129b, 0x1666), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x13b1, 0x001e), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x1435, 0x0711), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x14ea, 0xab10), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x14ea, 0xab13), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x157e, 0x300a), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x157e, 0x300b), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x157e, 0x3204), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x157e, 0x3207), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x1740, 0x2000), .driver_info = DEVICE_ZD1211 },
+	{ USB_DEVICE(0x6891, 0xa727), .driver_info = DEVICE_ZD1211 },
+	/* ZD1211B */
+	{ USB_DEVICE(0x0053, 0x5301), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0409, 0x0248), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0411, 0x00da), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0471, 0x1236), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0471, 0x1237), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x050d, 0x705c), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x054c, 0x0257), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0586, 0x340a), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0586, 0x340f), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0586, 0x3410), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0586, 0x3412), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0586, 0x3413), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x079b, 0x0062), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x07b8, 0x6001), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x07fa, 0x1196), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x083a, 0x4505), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x083a, 0xe501), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x083a, 0xe503), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x083a, 0xe506), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0ace, 0x1215), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0ace, 0xb215), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0b05, 0x171b), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0baf, 0x0121), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0cde, 0x001a), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x0df6, 0x0036), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x129b, 0x1667), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x13b1, 0x0024), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x157e, 0x300d), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x1582, 0x6003), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x2019, 0x5303), .driver_info = DEVICE_ZD1211B },
+	{ USB_DEVICE(0x2019, 0xed01), .driver_info = DEVICE_ZD1211B },
+	/* "Driverless" devices that need ejecting */
+	{ USB_DEVICE(0x0ace, 0x2011), .driver_info = DEVICE_INSTALLER },
+	{ USB_DEVICE(0x0ace, 0x20ff), .driver_info = DEVICE_INSTALLER },
+	{}
+};
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("USB driver for devices with the ZD1211 chip.");
+MODULE_AUTHOR("Ulrich Kunitz");
+MODULE_AUTHOR("Daniel Drake");
+MODULE_VERSION("1.0");
+MODULE_DEVICE_TABLE(usb, usb_ids);
+
+#define FW_ZD1211_PREFIX	"zd1211/zd1211_"
+#define FW_ZD1211B_PREFIX	"zd1211/zd1211b_"
+
+static bool check_read_regs(struct zd_usb *usb, struct usb_req_read_regs *req,
+			    unsigned int count);
+
+/* USB device initialization */
+static void int_urb_complete(struct urb *urb);
+
+static int request_fw_file(
+	const struct firmware **fw, const char *name, struct device *device)
+{
+	int r;
+
+	dev_dbg_f(device, "fw name %s\n", name);
+
+	r = request_firmware(fw, name, device);
+	if (r)
+		dev_err(device,
+		       "Could not load firmware file %s. Error number %d\n",
+		       name, r);
+	return r;
+}
+
+static inline u16 get_bcdDevice(const struct usb_device *udev)
+{
+	return le16_to_cpu(udev->descriptor.bcdDevice);
+}
+
+enum upload_code_flags {
+	REBOOT = 1,
+};
+
+/* Ensures that MAX_TRANSFER_SIZE is even. */
+#define MAX_TRANSFER_SIZE (USB_MAX_TRANSFER_SIZE & ~1)
+
+static int upload_code(struct usb_device *udev,
+	const u8 *data, size_t size, u16 code_offset, int flags)
+{
+	u8 *p;
+	int r;
+
+	/* USB request blocks need "kmalloced" buffers.
+	 */
+	p = kmalloc(MAX_TRANSFER_SIZE, GFP_KERNEL);
+	if (!p) {
+		r = -ENOMEM;
+		goto error;
+	}
+
+	size &= ~1;
+	while (size > 0) {
+		size_t transfer_size = size <= MAX_TRANSFER_SIZE ?
+			size : MAX_TRANSFER_SIZE;
+
+		dev_dbg_f(&udev->dev, "transfer size %zu\n", transfer_size);
+
+		memcpy(p, data, transfer_size);
+		r = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+			USB_REQ_FIRMWARE_DOWNLOAD,
+			USB_DIR_OUT | USB_TYPE_VENDOR,
+			code_offset, 0, p, transfer_size, 1000 /* ms */);
+		if (r < 0) {
+			dev_err(&udev->dev,
+			       "USB control request for firmware upload"
+			       " failed. Error number %d\n", r);
+			goto error;
+		}
+		transfer_size = r & ~1;
+
+		size -= transfer_size;
+		data += transfer_size;
+		code_offset += transfer_size/sizeof(u16);
+	}
+
+	if (flags & REBOOT) {
+		u8 ret;
+
+		/* Use "DMA-aware" buffer. */
+		r = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
+			USB_REQ_FIRMWARE_CONFIRM,
+			USB_DIR_IN | USB_TYPE_VENDOR,
+			0, 0, p, sizeof(ret), 5000 /* ms */);
+		if (r != sizeof(ret)) {
+			dev_err(&udev->dev,
+				"control request firmware confirmation failed."
+				" Return value %d\n", r);
+			if (r >= 0)
+				r = -ENODEV;
+			goto error;
+		}
+		ret = p[0];
+		if (ret & 0x80) {
+			dev_err(&udev->dev,
+				"Internal error while downloading."
+				" Firmware confirm return value %#04x\n",
+				(unsigned int)ret);
+			r = -ENODEV;
+			goto error;
+		}
+		dev_dbg_f(&udev->dev, "firmware confirm return value %#04x\n",
+			(unsigned int)ret);
+	}
+
+	r = 0;
+error:
+	kfree(p);
+	return r;
+}
+
+static u16 get_word(const void *data, u16 offset)
+{
+	const __le16 *p = data;
+	return le16_to_cpu(p[offset]);
+}
+
+static char *get_fw_name(struct zd_usb *usb, char *buffer, size_t size,
+	               const char* postfix)
+{
+	scnprintf(buffer, size, "%s%s",
+		usb->is_zd1211b ?
+			FW_ZD1211B_PREFIX : FW_ZD1211_PREFIX,
+		postfix);
+	return buffer;
+}
+
+static int handle_version_mismatch(struct zd_usb *usb,
+	const struct firmware *ub_fw)
+{
+	struct usb_device *udev = zd_usb_to_usbdev(usb);
+	const struct firmware *ur_fw = NULL;
+	int offset;
+	int r = 0;
+	char fw_name[128];
+
+	r = request_fw_file(&ur_fw,
+		get_fw_name(usb, fw_name, sizeof(fw_name), "ur"),
+		&udev->dev);
+	if (r)
+		goto error;
+
+	r = upload_code(udev, ur_fw->data, ur_fw->size, FW_START, REBOOT);
+	if (r)
+		goto error;
+
+	offset = (E2P_BOOT_CODE_OFFSET * sizeof(u16));
+	r = upload_code(udev, ub_fw->data + offset, ub_fw->size - offset,
+		E2P_START + E2P_BOOT_CODE_OFFSET, REBOOT);
+
+	/* At this point, the vendor driver downloads the whole firmware
+	 * image, hacks around with version IDs, and uploads it again,
+	 * completely overwriting the boot code. We do not do this here as
+	 * it is not required on any tested devices, and it is suspected to
+	 * cause problems. */
+error:
+	release_firmware(ur_fw);
+	return r;
+}
+
+static int upload_firmware(struct zd_usb *usb)
+{
+	int r;
+	u16 fw_bcdDevice;
+	u16 bcdDevice;
+	struct usb_device *udev = zd_usb_to_usbdev(usb);
+	const struct firmware *ub_fw = NULL;
+	const struct firmware *uph_fw = NULL;
+	char fw_name[128];
+
+	bcdDevice = get_bcdDevice(udev);
+
+	r = request_fw_file(&ub_fw,
+		get_fw_name(usb, fw_name, sizeof(fw_name), "ub"),
+		&udev->dev);
+	if (r)
+		goto error;
+
+	fw_bcdDevice = get_word(ub_fw->data, E2P_DATA_OFFSET);
+
+	if (fw_bcdDevice != bcdDevice) {
+		dev_info(&udev->dev,
+			"firmware version %#06x and device bootcode version "
+			"%#06x differ\n", fw_bcdDevice, bcdDevice);
+		if (bcdDevice <= 0x4313)
+			dev_warn(&udev->dev, "device has old bootcode, please "
+				"report success or failure\n");
+
+		r = handle_version_mismatch(usb, ub_fw);
+		if (r)
+			goto error;
+	} else {
+		dev_dbg_f(&udev->dev,
+			"firmware device id %#06x is equal to the "
+			"actual device id\n", fw_bcdDevice);
+	}
+
+
+	r = request_fw_file(&uph_fw,
+		get_fw_name(usb, fw_name, sizeof(fw_name), "uphr"),
+		&udev->dev);
+	if (r)
+		goto error;
+
+	r = upload_code(udev, uph_fw->data, uph_fw->size, FW_START, REBOOT);
+	if (r) {
+		dev_err(&udev->dev,
+			"Could not upload firmware code uph. Error number %d\n",
+			r);
+	}
+
+	/* FALL-THROUGH */
+error:
+	release_firmware(ub_fw);
+	release_firmware(uph_fw);
+	return r;
+}
+
+MODULE_FIRMWARE(FW_ZD1211B_PREFIX "ur");
+MODULE_FIRMWARE(FW_ZD1211_PREFIX "ur");
+MODULE_FIRMWARE(FW_ZD1211B_PREFIX "ub");
+MODULE_FIRMWARE(FW_ZD1211_PREFIX "ub");
+MODULE_FIRMWARE(FW_ZD1211B_PREFIX "uphr");
+MODULE_FIRMWARE(FW_ZD1211_PREFIX "uphr");
+
+/* Read data from device address space using "firmware interface" which does
+ * not require firmware to be loaded. */
+int zd_usb_read_fw(struct zd_usb *usb, zd_addr_t addr, u8 *data, u16 len)
+{
+	int r;
+	struct usb_device *udev = zd_usb_to_usbdev(usb);
+	u8 *buf;
+
+	/* Use "DMA-aware" buffer. */
+	buf = kmalloc(len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	r = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
+		USB_REQ_FIRMWARE_READ_DATA, USB_DIR_IN | 0x40, addr, 0,
+		buf, len, 5000);
+	if (r < 0) {
+		dev_err(&udev->dev,
+			"read over firmware interface failed: %d\n", r);
+		goto exit;
+	} else if (r != len) {
+		dev_err(&udev->dev,
+			"incomplete read over firmware interface: %d/%d\n",
+			r, len);
+		r = -EIO;
+		goto exit;
+	}
+	r = 0;
+	memcpy(data, buf, len);
+exit:
+	kfree(buf);
+	return r;
+}
+
+#define urb_dev(urb) (&(urb)->dev->dev)
+
+static inline void handle_regs_int_override(struct urb *urb)
+{
+	struct zd_usb *usb = urb->context;
+	struct zd_usb_interrupt *intr = &usb->intr;
+	unsigned long flags;
+
+	spin_lock_irqsave(&intr->lock, flags);
+	if (atomic_read(&intr->read_regs_enabled)) {
+		atomic_set(&intr->read_regs_enabled, 0);
+		intr->read_regs_int_overridden = 1;
+		complete(&intr->read_regs.completion);
+	}
+	spin_unlock_irqrestore(&intr->lock, flags);
+}
+
+static inline void handle_regs_int(struct urb *urb)
+{
+	struct zd_usb *usb = urb->context;
+	struct zd_usb_interrupt *intr = &usb->intr;
+	unsigned long flags;
+	int len;
+	u16 int_num;
+
+	spin_lock_irqsave(&intr->lock, flags);
+
+	int_num = le16_to_cpu(*(__le16 *)(urb->transfer_buffer+2));
+	if (int_num == CR_INTERRUPT) {
+		struct zd_mac *mac = zd_hw_mac(zd_usb_to_hw(urb->context));
+		spin_lock(&mac->lock);
+		memcpy(&mac->intr_buffer, urb->transfer_buffer,
+				USB_MAX_EP_INT_BUFFER);
+		spin_unlock(&mac->lock);
+		schedule_work(&mac->process_intr);
+	} else if (atomic_read(&intr->read_regs_enabled)) {
+		len = urb->actual_length;
+		intr->read_regs.length = urb->actual_length;
+		if (len > sizeof(intr->read_regs.buffer))
+			len = sizeof(intr->read_regs.buffer);
+
+		memcpy(intr->read_regs.buffer, urb->transfer_buffer, len);
+
+		/* Sometimes USB_INT_ID_REGS is not overridden, but comes after
+		 * USB_INT_ID_RETRY_FAILED. Read-reg retry then gets this
+		 * delayed USB_INT_ID_REGS, but leaves USB_INT_ID_REGS of
+		 * retry unhandled. Next read-reg command then might catch
+		 * this wrong USB_INT_ID_REGS. Fix by ignoring wrong reads.
+		 */
+		if (!check_read_regs(usb, intr->read_regs.req,
+						intr->read_regs.req_count))
+			goto out;
+
+		atomic_set(&intr->read_regs_enabled, 0);
+		intr->read_regs_int_overridden = 0;
+		complete(&intr->read_regs.completion);
+
+		goto out;
+	}
+
+out:
+	spin_unlock_irqrestore(&intr->lock, flags);
+
+	/* CR_INTERRUPT might override read_reg too. */
+	if (int_num == CR_INTERRUPT && atomic_read(&intr->read_regs_enabled))
+		handle_regs_int_override(urb);
+}
+
+static void int_urb_complete(struct urb *urb)
+{
+	int r;
+	struct usb_int_header *hdr;
+	struct zd_usb *usb;
+	struct zd_usb_interrupt *intr;
+
+	switch (urb->status) {
+	case 0:
+		break;
+	case -ESHUTDOWN:
+	case -EINVAL:
+	case -ENODEV:
+	case -ENOENT:
+	case -ECONNRESET:
+	case -EPIPE:
+		dev_dbg_f(urb_dev(urb), "urb %p error %d\n", urb, urb->status);
+		return;
+	default:
+		dev_dbg_f(urb_dev(urb), "urb %p error %d\n", urb, urb->status);
+		goto resubmit;
+	}
+
+	if (urb->actual_length < sizeof(hdr)) {
+		dev_dbg_f(urb_dev(urb), "error: urb %p to small\n", urb);
+		goto resubmit;
+	}
+
+	hdr = urb->transfer_buffer;
+	if (hdr->type != USB_INT_TYPE) {
+		dev_dbg_f(urb_dev(urb), "error: urb %p wrong type\n", urb);
+		goto resubmit;
+	}
+
+	/* USB_INT_ID_RETRY_FAILED triggered by tx-urb submit can override
+	 * pending USB_INT_ID_REGS causing read command timeout.
+	 */
+	usb = urb->context;
+	intr = &usb->intr;
+	if (hdr->id != USB_INT_ID_REGS && atomic_read(&intr->read_regs_enabled))
+		handle_regs_int_override(urb);
+
+	switch (hdr->id) {
+	case USB_INT_ID_REGS:
+		handle_regs_int(urb);
+		break;
+	case USB_INT_ID_RETRY_FAILED:
+		zd_mac_tx_failed(urb);
+		break;
+	default:
+		dev_dbg_f(urb_dev(urb), "error: urb %p unknown id %x\n", urb,
+			(unsigned int)hdr->id);
+		goto resubmit;
+	}
+
+resubmit:
+	r = usb_submit_urb(urb, GFP_ATOMIC);
+	if (r) {
+		dev_dbg_f(urb_dev(urb), "error: resubmit urb %p err code %d\n",
+			  urb, r);
+		/* TODO: add worker to reset intr->urb */
+	}
+	return;
+}
+
+static inline int int_urb_interval(struct usb_device *udev)
+{
+	switch (udev->speed) {
+	case USB_SPEED_HIGH:
+		return 4;
+	case USB_SPEED_LOW:
+		return 10;
+	case USB_SPEED_FULL:
+	default:
+		return 1;
+	}
+}
+
+static inline int usb_int_enabled(struct zd_usb *usb)
+{
+	unsigned long flags;
+	struct zd_usb_interrupt *intr = &usb->intr;
+	struct urb *urb;
+
+	spin_lock_irqsave(&intr->lock, flags);
+	urb = intr->urb;
+	spin_unlock_irqrestore(&intr->lock, flags);
+	return urb != NULL;
+}
+
+int zd_usb_enable_int(struct zd_usb *usb)
+{
+	int r;
+	struct usb_device *udev = zd_usb_to_usbdev(usb);
+	struct zd_usb_interrupt *intr = &usb->intr;
+	struct urb *urb;
+
+	dev_dbg_f(zd_usb_dev(usb), "\n");
+
+	urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!urb) {
+		r = -ENOMEM;
+		goto out;
+	}
+
+	ZD_ASSERT(!irqs_disabled());
+	spin_lock_irq(&intr->lock);
+	if (intr->urb) {
+		spin_unlock_irq(&intr->lock);
+		r = 0;
+		goto error_free_urb;
+	}
+	intr->urb = urb;
+	spin_unlock_irq(&intr->lock);
+
+	r = -ENOMEM;
+	intr->buffer = usb_alloc_coherent(udev, USB_MAX_EP_INT_BUFFER,
+					  GFP_KERNEL, &intr->buffer_dma);
+	if (!intr->buffer) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"couldn't allocate transfer_buffer\n");
+		goto error_set_urb_null;
+	}
+
+	usb_fill_int_urb(urb, udev, usb_rcvintpipe(udev, EP_INT_IN),
+			 intr->buffer, USB_MAX_EP_INT_BUFFER,
+			 int_urb_complete, usb,
+			 intr->interval);
+	urb->transfer_dma = intr->buffer_dma;
+	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+	dev_dbg_f(zd_usb_dev(usb), "submit urb %p\n", intr->urb);
+	r = usb_submit_urb(urb, GFP_KERNEL);
+	if (r) {
+		dev_dbg_f(zd_usb_dev(usb),
+			 "Couldn't submit urb. Error number %d\n", r);
+		goto error;
+	}
+
+	return 0;
+error:
+	usb_free_coherent(udev, USB_MAX_EP_INT_BUFFER,
+			  intr->buffer, intr->buffer_dma);
+error_set_urb_null:
+	spin_lock_irq(&intr->lock);
+	intr->urb = NULL;
+	spin_unlock_irq(&intr->lock);
+error_free_urb:
+	usb_free_urb(urb);
+out:
+	return r;
+}
+
+void zd_usb_disable_int(struct zd_usb *usb)
+{
+	unsigned long flags;
+	struct usb_device *udev = zd_usb_to_usbdev(usb);
+	struct zd_usb_interrupt *intr = &usb->intr;
+	struct urb *urb;
+	void *buffer;
+	dma_addr_t buffer_dma;
+
+	spin_lock_irqsave(&intr->lock, flags);
+	urb = intr->urb;
+	if (!urb) {
+		spin_unlock_irqrestore(&intr->lock, flags);
+		return;
+	}
+	intr->urb = NULL;
+	buffer = intr->buffer;
+	buffer_dma = intr->buffer_dma;
+	intr->buffer = NULL;
+	spin_unlock_irqrestore(&intr->lock, flags);
+
+	usb_kill_urb(urb);
+	dev_dbg_f(zd_usb_dev(usb), "urb %p killed\n", urb);
+	usb_free_urb(urb);
+
+	usb_free_coherent(udev, USB_MAX_EP_INT_BUFFER, buffer, buffer_dma);
+}
+
+static void handle_rx_packet(struct zd_usb *usb, const u8 *buffer,
+			     unsigned int length)
+{
+	int i;
+	const struct rx_length_info *length_info;
+
+	if (length < sizeof(struct rx_length_info)) {
+		/* It's not a complete packet anyhow. */
+		dev_dbg_f(zd_usb_dev(usb), "invalid, small RX packet : %d\n",
+					   length);
+		return;
+	}
+	length_info = (struct rx_length_info *)
+		(buffer + length - sizeof(struct rx_length_info));
+
+	/* It might be that three frames are merged into a single URB
+	 * transaction. We have to check for the length info tag.
+	 *
+	 * While testing we discovered that length_info might be unaligned,
+	 * because if USB transactions are merged, the last packet will not
+	 * be padded. Unaligned access might also happen if the length_info
+	 * structure is not present.
+	 */
+	if (get_unaligned_le16(&length_info->tag) == RX_LENGTH_INFO_TAG)
+	{
+		unsigned int l, k, n;
+		for (i = 0, l = 0;; i++) {
+			k = get_unaligned_le16(&length_info->length[i]);
+			if (k == 0)
+				return;
+			n = l+k;
+			if (n > length)
+				return;
+			zd_mac_rx(zd_usb_to_hw(usb), buffer+l, k);
+			if (i >= 2)
+				return;
+			l = (n+3) & ~3;
+		}
+	} else {
+		zd_mac_rx(zd_usb_to_hw(usb), buffer, length);
+	}
+}
+
+static void rx_urb_complete(struct urb *urb)
+{
+	int r;
+	struct zd_usb *usb;
+	struct zd_usb_rx *rx;
+	const u8 *buffer;
+	unsigned int length;
+	unsigned long flags;
+
+	switch (urb->status) {
+	case 0:
+		break;
+	case -ESHUTDOWN:
+	case -EINVAL:
+	case -ENODEV:
+	case -ENOENT:
+	case -ECONNRESET:
+	case -EPIPE:
+		dev_dbg_f(urb_dev(urb), "urb %p error %d\n", urb, urb->status);
+		return;
+	default:
+		dev_dbg_f(urb_dev(urb), "urb %p error %d\n", urb, urb->status);
+		goto resubmit;
+	}
+
+	buffer = urb->transfer_buffer;
+	length = urb->actual_length;
+	usb = urb->context;
+	rx = &usb->rx;
+
+	tasklet_schedule(&rx->reset_timer_tasklet);
+
+	if (length%rx->usb_packet_size > rx->usb_packet_size-4) {
+		/* If there is an old first fragment, we don't care. */
+		dev_dbg_f(urb_dev(urb), "*** first fragment ***\n");
+		ZD_ASSERT(length <= ARRAY_SIZE(rx->fragment));
+		spin_lock_irqsave(&rx->lock, flags);
+		memcpy(rx->fragment, buffer, length);
+		rx->fragment_length = length;
+		spin_unlock_irqrestore(&rx->lock, flags);
+		goto resubmit;
+	}
+
+	spin_lock_irqsave(&rx->lock, flags);
+	if (rx->fragment_length > 0) {
+		/* We are on a second fragment, we believe */
+		ZD_ASSERT(length + rx->fragment_length <=
+			  ARRAY_SIZE(rx->fragment));
+		dev_dbg_f(urb_dev(urb), "*** second fragment ***\n");
+		memcpy(rx->fragment+rx->fragment_length, buffer, length);
+		handle_rx_packet(usb, rx->fragment,
+			         rx->fragment_length + length);
+		rx->fragment_length = 0;
+		spin_unlock_irqrestore(&rx->lock, flags);
+	} else {
+		spin_unlock_irqrestore(&rx->lock, flags);
+		handle_rx_packet(usb, buffer, length);
+	}
+
+resubmit:
+	r = usb_submit_urb(urb, GFP_ATOMIC);
+	if (r)
+		dev_dbg_f(urb_dev(urb), "urb %p resubmit error %d\n", urb, r);
+}
+
+static struct urb *alloc_rx_urb(struct zd_usb *usb)
+{
+	struct usb_device *udev = zd_usb_to_usbdev(usb);
+	struct urb *urb;
+	void *buffer;
+
+	urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!urb)
+		return NULL;
+	buffer = usb_alloc_coherent(udev, USB_MAX_RX_SIZE, GFP_KERNEL,
+				    &urb->transfer_dma);
+	if (!buffer) {
+		usb_free_urb(urb);
+		return NULL;
+	}
+
+	usb_fill_bulk_urb(urb, udev, usb_rcvbulkpipe(udev, EP_DATA_IN),
+			  buffer, USB_MAX_RX_SIZE,
+			  rx_urb_complete, usb);
+	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+	return urb;
+}
+
+static void free_rx_urb(struct urb *urb)
+{
+	if (!urb)
+		return;
+	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
+			  urb->transfer_buffer, urb->transfer_dma);
+	usb_free_urb(urb);
+}
+
+static int __zd_usb_enable_rx(struct zd_usb *usb)
+{
+	int i, r;
+	struct zd_usb_rx *rx = &usb->rx;
+	struct urb **urbs;
+
+	dev_dbg_f(zd_usb_dev(usb), "\n");
+
+	r = -ENOMEM;
+	urbs = kcalloc(RX_URBS_COUNT, sizeof(struct urb *), GFP_KERNEL);
+	if (!urbs)
+		goto error;
+	for (i = 0; i < RX_URBS_COUNT; i++) {
+		urbs[i] = alloc_rx_urb(usb);
+		if (!urbs[i])
+			goto error;
+	}
+
+	ZD_ASSERT(!irqs_disabled());
+	spin_lock_irq(&rx->lock);
+	if (rx->urbs) {
+		spin_unlock_irq(&rx->lock);
+		r = 0;
+		goto error;
+	}
+	rx->urbs = urbs;
+	rx->urbs_count = RX_URBS_COUNT;
+	spin_unlock_irq(&rx->lock);
+
+	for (i = 0; i < RX_URBS_COUNT; i++) {
+		r = usb_submit_urb(urbs[i], GFP_KERNEL);
+		if (r)
+			goto error_submit;
+	}
+
+	return 0;
+error_submit:
+	for (i = 0; i < RX_URBS_COUNT; i++) {
+		usb_kill_urb(urbs[i]);
+	}
+	spin_lock_irq(&rx->lock);
+	rx->urbs = NULL;
+	rx->urbs_count = 0;
+	spin_unlock_irq(&rx->lock);
+error:
+	if (urbs) {
+		for (i = 0; i < RX_URBS_COUNT; i++)
+			free_rx_urb(urbs[i]);
+	}
+	return r;
+}
+
+int zd_usb_enable_rx(struct zd_usb *usb)
+{
+	int r;
+	struct zd_usb_rx *rx = &usb->rx;
+
+	mutex_lock(&rx->setup_mutex);
+	r = __zd_usb_enable_rx(usb);
+	mutex_unlock(&rx->setup_mutex);
+
+	zd_usb_reset_rx_idle_timer(usb);
+
+	return r;
+}
+
+static void __zd_usb_disable_rx(struct zd_usb *usb)
+{
+	int i;
+	unsigned long flags;
+	struct urb **urbs;
+	unsigned int count;
+	struct zd_usb_rx *rx = &usb->rx;
+
+	spin_lock_irqsave(&rx->lock, flags);
+	urbs = rx->urbs;
+	count = rx->urbs_count;
+	spin_unlock_irqrestore(&rx->lock, flags);
+	if (!urbs)
+		return;
+
+	for (i = 0; i < count; i++) {
+		usb_kill_urb(urbs[i]);
+		free_rx_urb(urbs[i]);
+	}
+	kfree(urbs);
+
+	spin_lock_irqsave(&rx->lock, flags);
+	rx->urbs = NULL;
+	rx->urbs_count = 0;
+	spin_unlock_irqrestore(&rx->lock, flags);
+}
+
+void zd_usb_disable_rx(struct zd_usb *usb)
+{
+	struct zd_usb_rx *rx = &usb->rx;
+
+	mutex_lock(&rx->setup_mutex);
+	__zd_usb_disable_rx(usb);
+	mutex_unlock(&rx->setup_mutex);
+
+	tasklet_kill(&rx->reset_timer_tasklet);
+	cancel_delayed_work_sync(&rx->idle_work);
+}
+
+static void zd_usb_reset_rx(struct zd_usb *usb)
+{
+	bool do_reset;
+	struct zd_usb_rx *rx = &usb->rx;
+	unsigned long flags;
+
+	mutex_lock(&rx->setup_mutex);
+
+	spin_lock_irqsave(&rx->lock, flags);
+	do_reset = rx->urbs != NULL;
+	spin_unlock_irqrestore(&rx->lock, flags);
+
+	if (do_reset) {
+		__zd_usb_disable_rx(usb);
+		__zd_usb_enable_rx(usb);
+	}
+
+	mutex_unlock(&rx->setup_mutex);
+
+	if (do_reset)
+		zd_usb_reset_rx_idle_timer(usb);
+}
+
+/**
+ * zd_usb_disable_tx - disable transmission
+ * @usb: the zd1211rw-private USB structure
+ *
+ * Frees all URBs in the free list and marks the transmission as disabled.
+ */
+void zd_usb_disable_tx(struct zd_usb *usb)
+{
+	struct zd_usb_tx *tx = &usb->tx;
+	unsigned long flags;
+
+	atomic_set(&tx->enabled, 0);
+
+	/* kill all submitted tx-urbs */
+	usb_kill_anchored_urbs(&tx->submitted);
+
+	spin_lock_irqsave(&tx->lock, flags);
+	WARN_ON(!skb_queue_empty(&tx->submitted_skbs));
+	WARN_ON(tx->submitted_urbs != 0);
+	tx->submitted_urbs = 0;
+	spin_unlock_irqrestore(&tx->lock, flags);
+
+	/* The stopped state is ignored, relying on ieee80211_wake_queues()
+	 * in a potentionally following zd_usb_enable_tx().
+	 */
+}
+
+/**
+ * zd_usb_enable_tx - enables transmission
+ * @usb: a &struct zd_usb pointer
+ *
+ * This function enables transmission and prepares the &zd_usb_tx data
+ * structure.
+ */
+void zd_usb_enable_tx(struct zd_usb *usb)
+{
+	unsigned long flags;
+	struct zd_usb_tx *tx = &usb->tx;
+
+	spin_lock_irqsave(&tx->lock, flags);
+	atomic_set(&tx->enabled, 1);
+	tx->submitted_urbs = 0;
+	ieee80211_wake_queues(zd_usb_to_hw(usb));
+	tx->stopped = 0;
+	spin_unlock_irqrestore(&tx->lock, flags);
+}
+
+static void tx_dec_submitted_urbs(struct zd_usb *usb)
+{
+	struct zd_usb_tx *tx = &usb->tx;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tx->lock, flags);
+	--tx->submitted_urbs;
+	if (tx->stopped && tx->submitted_urbs <= ZD_USB_TX_LOW) {
+		ieee80211_wake_queues(zd_usb_to_hw(usb));
+		tx->stopped = 0;
+	}
+	spin_unlock_irqrestore(&tx->lock, flags);
+}
+
+static void tx_inc_submitted_urbs(struct zd_usb *usb)
+{
+	struct zd_usb_tx *tx = &usb->tx;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tx->lock, flags);
+	++tx->submitted_urbs;
+	if (!tx->stopped && tx->submitted_urbs > ZD_USB_TX_HIGH) {
+		ieee80211_stop_queues(zd_usb_to_hw(usb));
+		tx->stopped = 1;
+	}
+	spin_unlock_irqrestore(&tx->lock, flags);
+}
+
+/**
+ * tx_urb_complete - completes the execution of an URB
+ * @urb: a URB
+ *
+ * This function is called if the URB has been transferred to a device or an
+ * error has happened.
+ */
+static void tx_urb_complete(struct urb *urb)
+{
+	int r;
+	struct sk_buff *skb;
+	struct ieee80211_tx_info *info;
+	struct zd_usb *usb;
+	struct zd_usb_tx *tx;
+
+	skb = (struct sk_buff *)urb->context;
+	info = IEEE80211_SKB_CB(skb);
+	/*
+	 * grab 'usb' pointer before handing off the skb (since
+	 * it might be freed by zd_mac_tx_to_dev or mac80211)
+	 */
+	usb = &zd_hw_mac(info->rate_driver_data[0])->chip.usb;
+	tx = &usb->tx;
+
+	switch (urb->status) {
+	case 0:
+		break;
+	case -ESHUTDOWN:
+	case -EINVAL:
+	case -ENODEV:
+	case -ENOENT:
+	case -ECONNRESET:
+	case -EPIPE:
+		dev_dbg_f(urb_dev(urb), "urb %p error %d\n", urb, urb->status);
+		break;
+	default:
+		dev_dbg_f(urb_dev(urb), "urb %p error %d\n", urb, urb->status);
+		goto resubmit;
+	}
+free_urb:
+	skb_unlink(skb, &usb->tx.submitted_skbs);
+	zd_mac_tx_to_dev(skb, urb->status);
+	usb_free_urb(urb);
+	tx_dec_submitted_urbs(usb);
+	return;
+resubmit:
+	usb_anchor_urb(urb, &tx->submitted);
+	r = usb_submit_urb(urb, GFP_ATOMIC);
+	if (r) {
+		usb_unanchor_urb(urb);
+		dev_dbg_f(urb_dev(urb), "error resubmit urb %p %d\n", urb, r);
+		goto free_urb;
+	}
+}
+
+/**
+ * zd_usb_tx: initiates transfer of a frame of the device
+ *
+ * @usb: the zd1211rw-private USB structure
+ * @skb: a &struct sk_buff pointer
+ *
+ * This function tranmits a frame to the device. It doesn't wait for
+ * completion. The frame must contain the control set and have all the
+ * control set information available.
+ *
+ * The function returns 0 if the transfer has been successfully initiated.
+ */
+int zd_usb_tx(struct zd_usb *usb, struct sk_buff *skb)
+{
+	int r;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct usb_device *udev = zd_usb_to_usbdev(usb);
+	struct urb *urb;
+	struct zd_usb_tx *tx = &usb->tx;
+
+	if (!atomic_read(&tx->enabled)) {
+		r = -ENOENT;
+		goto out;
+	}
+
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if (!urb) {
+		r = -ENOMEM;
+		goto out;
+	}
+
+	usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT),
+		          skb->data, skb->len, tx_urb_complete, skb);
+
+	info->rate_driver_data[1] = (void *)jiffies;
+	skb_queue_tail(&tx->submitted_skbs, skb);
+	usb_anchor_urb(urb, &tx->submitted);
+
+	r = usb_submit_urb(urb, GFP_ATOMIC);
+	if (r) {
+		dev_dbg_f(zd_usb_dev(usb), "error submit urb %p %d\n", urb, r);
+		usb_unanchor_urb(urb);
+		skb_unlink(skb, &tx->submitted_skbs);
+		goto error;
+	}
+	tx_inc_submitted_urbs(usb);
+	return 0;
+error:
+	usb_free_urb(urb);
+out:
+	return r;
+}
+
+static bool zd_tx_timeout(struct zd_usb *usb)
+{
+	struct zd_usb_tx *tx = &usb->tx;
+	struct sk_buff_head *q = &tx->submitted_skbs;
+	struct sk_buff *skb, *skbnext;
+	struct ieee80211_tx_info *info;
+	unsigned long flags, trans_start;
+	bool have_timedout = false;
+
+	spin_lock_irqsave(&q->lock, flags);
+	skb_queue_walk_safe(q, skb, skbnext) {
+		info = IEEE80211_SKB_CB(skb);
+		trans_start = (unsigned long)info->rate_driver_data[1];
+
+		if (time_is_before_jiffies(trans_start + ZD_TX_TIMEOUT)) {
+			have_timedout = true;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&q->lock, flags);
+
+	return have_timedout;
+}
+
+static void zd_tx_watchdog_handler(struct work_struct *work)
+{
+	struct zd_usb *usb =
+		container_of(work, struct zd_usb, tx.watchdog_work.work);
+	struct zd_usb_tx *tx = &usb->tx;
+
+	if (!atomic_read(&tx->enabled) || !tx->watchdog_enabled)
+		goto out;
+	if (!zd_tx_timeout(usb))
+		goto out;
+
+	/* TX halted, try reset */
+	dev_warn(zd_usb_dev(usb), "TX-stall detected, resetting device...");
+
+	usb_queue_reset_device(usb->intf);
+
+	/* reset will stop this worker, don't rearm */
+	return;
+out:
+	queue_delayed_work(zd_workqueue, &tx->watchdog_work,
+			   ZD_TX_WATCHDOG_INTERVAL);
+}
+
+void zd_tx_watchdog_enable(struct zd_usb *usb)
+{
+	struct zd_usb_tx *tx = &usb->tx;
+
+	if (!tx->watchdog_enabled) {
+		dev_dbg_f(zd_usb_dev(usb), "\n");
+		queue_delayed_work(zd_workqueue, &tx->watchdog_work,
+				   ZD_TX_WATCHDOG_INTERVAL);
+		tx->watchdog_enabled = 1;
+	}
+}
+
+void zd_tx_watchdog_disable(struct zd_usb *usb)
+{
+	struct zd_usb_tx *tx = &usb->tx;
+
+	if (tx->watchdog_enabled) {
+		dev_dbg_f(zd_usb_dev(usb), "\n");
+		tx->watchdog_enabled = 0;
+		cancel_delayed_work_sync(&tx->watchdog_work);
+	}
+}
+
+static void zd_rx_idle_timer_handler(struct work_struct *work)
+{
+	struct zd_usb *usb =
+		container_of(work, struct zd_usb, rx.idle_work.work);
+	struct zd_mac *mac = zd_usb_to_mac(usb);
+
+	if (!test_bit(ZD_DEVICE_RUNNING, &mac->flags))
+		return;
+
+	dev_dbg_f(zd_usb_dev(usb), "\n");
+
+	/* 30 seconds since last rx, reset rx */
+	zd_usb_reset_rx(usb);
+}
+
+static void zd_usb_reset_rx_idle_timer_tasklet(struct tasklet_struct *t)
+{
+	struct zd_usb *usb = from_tasklet(usb, t, rx.reset_timer_tasklet);
+
+	zd_usb_reset_rx_idle_timer(usb);
+}
+
+void zd_usb_reset_rx_idle_timer(struct zd_usb *usb)
+{
+	struct zd_usb_rx *rx = &usb->rx;
+
+	mod_delayed_work(zd_workqueue, &rx->idle_work, ZD_RX_IDLE_INTERVAL);
+}
+
+static inline void init_usb_interrupt(struct zd_usb *usb)
+{
+	struct zd_usb_interrupt *intr = &usb->intr;
+
+	spin_lock_init(&intr->lock);
+	intr->interval = int_urb_interval(zd_usb_to_usbdev(usb));
+	init_completion(&intr->read_regs.completion);
+	atomic_set(&intr->read_regs_enabled, 0);
+	intr->read_regs.cr_int_addr = cpu_to_le16((u16)CR_INTERRUPT);
+}
+
+static inline void init_usb_rx(struct zd_usb *usb)
+{
+	struct zd_usb_rx *rx = &usb->rx;
+
+	spin_lock_init(&rx->lock);
+	mutex_init(&rx->setup_mutex);
+	if (interface_to_usbdev(usb->intf)->speed == USB_SPEED_HIGH) {
+		rx->usb_packet_size = 512;
+	} else {
+		rx->usb_packet_size = 64;
+	}
+	ZD_ASSERT(rx->fragment_length == 0);
+	INIT_DELAYED_WORK(&rx->idle_work, zd_rx_idle_timer_handler);
+	rx->reset_timer_tasklet.func = (void (*))
+					zd_usb_reset_rx_idle_timer_tasklet;
+	rx->reset_timer_tasklet.data = (unsigned long)&rx->reset_timer_tasklet;
+}
+
+static inline void init_usb_tx(struct zd_usb *usb)
+{
+	struct zd_usb_tx *tx = &usb->tx;
+
+	spin_lock_init(&tx->lock);
+	atomic_set(&tx->enabled, 0);
+	tx->stopped = 0;
+	skb_queue_head_init(&tx->submitted_skbs);
+	init_usb_anchor(&tx->submitted);
+	tx->submitted_urbs = 0;
+	tx->watchdog_enabled = 0;
+	INIT_DELAYED_WORK(&tx->watchdog_work, zd_tx_watchdog_handler);
+}
+
+void zd_usb_init(struct zd_usb *usb, struct ieee80211_hw *hw,
+	         struct usb_interface *intf)
+{
+	memset(usb, 0, sizeof(*usb));
+	usb->intf = usb_get_intf(intf);
+	usb_set_intfdata(usb->intf, hw);
+	init_usb_anchor(&usb->submitted_cmds);
+	init_usb_interrupt(usb);
+	init_usb_tx(usb);
+	init_usb_rx(usb);
+}
+
+void zd_usb_clear(struct zd_usb *usb)
+{
+	usb_set_intfdata(usb->intf, NULL);
+	usb_put_intf(usb->intf);
+	ZD_MEMCLEAR(usb, sizeof(*usb));
+	/* FIXME: usb_interrupt, usb_tx, usb_rx? */
+}
+
+static const char *speed(enum usb_device_speed speed)
+{
+	switch (speed) {
+	case USB_SPEED_LOW:
+		return "low";
+	case USB_SPEED_FULL:
+		return "full";
+	case USB_SPEED_HIGH:
+		return "high";
+	default:
+		return "unknown speed";
+	}
+}
+
+static int scnprint_id(struct usb_device *udev, char *buffer, size_t size)
+{
+	return scnprintf(buffer, size, "%04hx:%04hx v%04hx %s",
+		le16_to_cpu(udev->descriptor.idVendor),
+		le16_to_cpu(udev->descriptor.idProduct),
+		get_bcdDevice(udev),
+		speed(udev->speed));
+}
+
+int zd_usb_scnprint_id(struct zd_usb *usb, char *buffer, size_t size)
+{
+	struct usb_device *udev = interface_to_usbdev(usb->intf);
+	return scnprint_id(udev, buffer, size);
+}
+
+#ifdef DEBUG
+static void print_id(struct usb_device *udev)
+{
+	char buffer[40];
+
+	scnprint_id(udev, buffer, sizeof(buffer));
+	buffer[sizeof(buffer)-1] = 0;
+	dev_dbg_f(&udev->dev, "%s\n", buffer);
+}
+#else
+#define print_id(udev) do { } while (0)
+#endif
+
+static int eject_installer(struct usb_interface *intf)
+{
+	struct usb_device *udev = interface_to_usbdev(intf);
+	struct usb_host_interface *iface_desc = intf->cur_altsetting;
+	struct usb_endpoint_descriptor *endpoint;
+	unsigned char *cmd;
+	u8 bulk_out_ep;
+	int r;
+
+	if (iface_desc->desc.bNumEndpoints < 2)
+		return -ENODEV;
+
+	/* Find bulk out endpoint */
+	for (r = 1; r >= 0; r--) {
+		endpoint = &iface_desc->endpoint[r].desc;
+		if (usb_endpoint_dir_out(endpoint) &&
+		    usb_endpoint_xfer_bulk(endpoint)) {
+			bulk_out_ep = endpoint->bEndpointAddress;
+			break;
+		}
+	}
+	if (r == -1) {
+		dev_err(&udev->dev,
+			"zd1211rw: Could not find bulk out endpoint\n");
+		return -ENODEV;
+	}
+
+	cmd = kzalloc(31, GFP_KERNEL);
+	if (cmd == NULL)
+		return -ENODEV;
+
+	/* USB bulk command block */
+	cmd[0] = 0x55;	/* bulk command signature */
+	cmd[1] = 0x53;	/* bulk command signature */
+	cmd[2] = 0x42;	/* bulk command signature */
+	cmd[3] = 0x43;	/* bulk command signature */
+	cmd[14] = 6;	/* command length */
+
+	cmd[15] = 0x1b;	/* SCSI command: START STOP UNIT */
+	cmd[19] = 0x2;	/* eject disc */
+
+	dev_info(&udev->dev, "Ejecting virtual installer media...\n");
+	r = usb_bulk_msg(udev, usb_sndbulkpipe(udev, bulk_out_ep),
+		cmd, 31, NULL, 2000);
+	kfree(cmd);
+	if (r)
+		return r;
+
+	/* At this point, the device disconnects and reconnects with the real
+	 * ID numbers. */
+
+	usb_set_intfdata(intf, NULL);
+	return 0;
+}
+
+int zd_usb_init_hw(struct zd_usb *usb)
+{
+	int r;
+	struct zd_mac *mac = zd_usb_to_mac(usb);
+
+	dev_dbg_f(zd_usb_dev(usb), "\n");
+
+	r = upload_firmware(usb);
+	if (r) {
+		dev_err(zd_usb_dev(usb),
+		       "couldn't load firmware. Error number %d\n", r);
+		return r;
+	}
+
+	r = usb_reset_configuration(zd_usb_to_usbdev(usb));
+	if (r) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"couldn't reset configuration. Error number %d\n", r);
+		return r;
+	}
+
+	r = zd_mac_init_hw(mac->hw);
+	if (r) {
+		dev_dbg_f(zd_usb_dev(usb),
+		         "couldn't initialize mac. Error number %d\n", r);
+		return r;
+	}
+
+	usb->initialized = 1;
+	return 0;
+}
+
+static int probe(struct usb_interface *intf, const struct usb_device_id *id)
+{
+	int r;
+	struct usb_device *udev = interface_to_usbdev(intf);
+	struct zd_usb *usb;
+	struct ieee80211_hw *hw = NULL;
+
+	print_id(udev);
+
+	if (id->driver_info & DEVICE_INSTALLER)
+		return eject_installer(intf);
+
+	switch (udev->speed) {
+	case USB_SPEED_LOW:
+	case USB_SPEED_FULL:
+	case USB_SPEED_HIGH:
+		break;
+	default:
+		dev_dbg_f(&intf->dev, "Unknown USB speed\n");
+		r = -ENODEV;
+		goto error;
+	}
+
+	r = usb_reset_device(udev);
+	if (r) {
+		dev_err(&intf->dev,
+			"couldn't reset usb device. Error number %d\n", r);
+		goto error;
+	}
+
+	hw = zd_mac_alloc_hw(intf);
+	if (hw == NULL) {
+		r = -ENOMEM;
+		goto error;
+	}
+
+	usb = &zd_hw_mac(hw)->chip.usb;
+	usb->is_zd1211b = (id->driver_info == DEVICE_ZD1211B) != 0;
+
+	r = zd_mac_preinit_hw(hw);
+	if (r) {
+		dev_dbg_f(&intf->dev,
+		         "couldn't initialize mac. Error number %d\n", r);
+		goto error;
+	}
+
+	r = ieee80211_register_hw(hw);
+	if (r) {
+		dev_dbg_f(&intf->dev,
+			 "couldn't register device. Error number %d\n", r);
+		goto error;
+	}
+
+	dev_dbg_f(&intf->dev, "successful\n");
+	dev_info(&intf->dev, "%s\n", wiphy_name(hw->wiphy));
+	return 0;
+error:
+	usb_reset_device(interface_to_usbdev(intf));
+	if (hw) {
+		zd_mac_clear(zd_hw_mac(hw));
+		ieee80211_free_hw(hw);
+	}
+	return r;
+}
+
+static void disconnect(struct usb_interface *intf)
+{
+	struct ieee80211_hw *hw = zd_intf_to_hw(intf);
+	struct zd_mac *mac;
+	struct zd_usb *usb;
+
+	/* Either something really bad happened, or we're just dealing with
+	 * a DEVICE_INSTALLER. */
+	if (hw == NULL)
+		return;
+
+	mac = zd_hw_mac(hw);
+	usb = &mac->chip.usb;
+
+	dev_dbg_f(zd_usb_dev(usb), "\n");
+
+	ieee80211_unregister_hw(hw);
+
+	/* Just in case something has gone wrong! */
+	zd_usb_disable_tx(usb);
+	zd_usb_disable_rx(usb);
+	zd_usb_disable_int(usb);
+
+	/* If the disconnect has been caused by a removal of the
+	 * driver module, the reset allows reloading of the driver. If the
+	 * reset will not be executed here, the upload of the firmware in the
+	 * probe function caused by the reloading of the driver will fail.
+	 */
+	usb_reset_device(interface_to_usbdev(intf));
+
+	zd_mac_clear(mac);
+	ieee80211_free_hw(hw);
+	dev_dbg(&intf->dev, "disconnected\n");
+}
+
+static void zd_usb_resume(struct zd_usb *usb)
+{
+	struct zd_mac *mac = zd_usb_to_mac(usb);
+	int r;
+
+	dev_dbg_f(zd_usb_dev(usb), "\n");
+
+	r = zd_op_start(zd_usb_to_hw(usb));
+	if (r < 0) {
+		dev_warn(zd_usb_dev(usb), "Device resume failed "
+			 "with error code %d. Retrying...\n", r);
+		if (usb->was_running)
+			set_bit(ZD_DEVICE_RUNNING, &mac->flags);
+		usb_queue_reset_device(usb->intf);
+		return;
+	}
+
+	if (mac->type != NL80211_IFTYPE_UNSPECIFIED) {
+		r = zd_restore_settings(mac);
+		if (r < 0) {
+			dev_dbg(zd_usb_dev(usb),
+				"failed to restore settings, %d\n", r);
+			return;
+		}
+	}
+}
+
+static void zd_usb_stop(struct zd_usb *usb)
+{
+	dev_dbg_f(zd_usb_dev(usb), "\n");
+
+	zd_op_stop(zd_usb_to_hw(usb));
+
+	zd_usb_disable_tx(usb);
+	zd_usb_disable_rx(usb);
+	zd_usb_disable_int(usb);
+
+	usb->initialized = 0;
+}
+
+static int pre_reset(struct usb_interface *intf)
+{
+	struct ieee80211_hw *hw = usb_get_intfdata(intf);
+	struct zd_mac *mac;
+	struct zd_usb *usb;
+
+	if (!hw || intf->condition != USB_INTERFACE_BOUND)
+		return 0;
+
+	mac = zd_hw_mac(hw);
+	usb = &mac->chip.usb;
+
+	usb->was_running = test_bit(ZD_DEVICE_RUNNING, &mac->flags);
+
+	zd_usb_stop(usb);
+
+	mutex_lock(&mac->chip.mutex);
+	return 0;
+}
+
+static int post_reset(struct usb_interface *intf)
+{
+	struct ieee80211_hw *hw = usb_get_intfdata(intf);
+	struct zd_mac *mac;
+	struct zd_usb *usb;
+
+	if (!hw || intf->condition != USB_INTERFACE_BOUND)
+		return 0;
+
+	mac = zd_hw_mac(hw);
+	usb = &mac->chip.usb;
+
+	mutex_unlock(&mac->chip.mutex);
+
+	if (usb->was_running)
+		zd_usb_resume(usb);
+	return 0;
+}
+
+static struct usb_driver driver = {
+	.name		= KBUILD_MODNAME,
+	.id_table	= usb_ids,
+	.probe		= probe,
+	.disconnect	= disconnect,
+	.pre_reset	= pre_reset,
+	.post_reset	= post_reset,
+	.disable_hub_initiated_lpm = 1,
+};
+
+struct workqueue_struct *zd_workqueue;
+
+static int __init usb_init(void)
+{
+	int r;
+
+	pr_debug("%s usb_init()\n", driver.name);
+
+	zd_workqueue = create_singlethread_workqueue(driver.name);
+	if (zd_workqueue == NULL) {
+		printk(KERN_ERR "%s couldn't create workqueue\n", driver.name);
+		return -ENOMEM;
+	}
+
+	r = usb_register(&driver);
+	if (r) {
+		destroy_workqueue(zd_workqueue);
+		printk(KERN_ERR "%s usb_register() failed. Error number %d\n",
+		       driver.name, r);
+		return r;
+	}
+
+	pr_debug("%s initialized\n", driver.name);
+	return 0;
+}
+
+static void __exit usb_exit(void)
+{
+	pr_debug("%s usb_exit()\n", driver.name);
+	usb_deregister(&driver);
+	destroy_workqueue(zd_workqueue);
+}
+
+module_init(usb_init);
+module_exit(usb_exit);
+
+static int zd_ep_regs_out_msg(struct usb_device *udev, void *data, int len,
+			      int *actual_length, int timeout)
+{
+	/* In USB 2.0 mode EP_REGS_OUT endpoint is interrupt type. However in
+	 * USB 1.1 mode endpoint is bulk. Select correct type URB by endpoint
+	 * descriptor.
+	 */
+	struct usb_host_endpoint *ep;
+	unsigned int pipe;
+
+	pipe = usb_sndintpipe(udev, EP_REGS_OUT);
+	ep = usb_pipe_endpoint(udev, pipe);
+	if (!ep)
+		return -EINVAL;
+
+	if (usb_endpoint_xfer_int(&ep->desc)) {
+		return usb_interrupt_msg(udev, pipe, data, len,
+					 actual_length, timeout);
+	} else {
+		pipe = usb_sndbulkpipe(udev, EP_REGS_OUT);
+		return usb_bulk_msg(udev, pipe, data, len, actual_length,
+				    timeout);
+	}
+}
+
+static void prepare_read_regs_int(struct zd_usb *usb,
+				  struct usb_req_read_regs *req,
+				  unsigned int count)
+{
+	struct zd_usb_interrupt *intr = &usb->intr;
+
+	spin_lock_irq(&intr->lock);
+	atomic_set(&intr->read_regs_enabled, 1);
+	intr->read_regs.req = req;
+	intr->read_regs.req_count = count;
+	reinit_completion(&intr->read_regs.completion);
+	spin_unlock_irq(&intr->lock);
+}
+
+static void disable_read_regs_int(struct zd_usb *usb)
+{
+	struct zd_usb_interrupt *intr = &usb->intr;
+
+	spin_lock_irq(&intr->lock);
+	atomic_set(&intr->read_regs_enabled, 0);
+	spin_unlock_irq(&intr->lock);
+}
+
+static bool check_read_regs(struct zd_usb *usb, struct usb_req_read_regs *req,
+			    unsigned int count)
+{
+	int i;
+	struct zd_usb_interrupt *intr = &usb->intr;
+	struct read_regs_int *rr = &intr->read_regs;
+	struct usb_int_regs *regs = (struct usb_int_regs *)rr->buffer;
+
+	/* The created block size seems to be larger than expected.
+	 * However results appear to be correct.
+	 */
+	if (rr->length < struct_size(regs, regs, count)) {
+		dev_dbg_f(zd_usb_dev(usb),
+			 "error: actual length %d less than expected %zu\n",
+			 rr->length, struct_size(regs, regs, count));
+		return false;
+	}
+
+	if (rr->length > sizeof(rr->buffer)) {
+		dev_dbg_f(zd_usb_dev(usb),
+			 "error: actual length %d exceeds buffer size %zu\n",
+			 rr->length, sizeof(rr->buffer));
+		return false;
+	}
+
+	for (i = 0; i < count; i++) {
+		struct reg_data *rd = &regs->regs[i];
+		if (rd->addr != req->addr[i]) {
+			dev_dbg_f(zd_usb_dev(usb),
+				 "rd[%d] addr %#06hx expected %#06hx\n", i,
+				 le16_to_cpu(rd->addr),
+				 le16_to_cpu(req->addr[i]));
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static int get_results(struct zd_usb *usb, u16 *values,
+		       struct usb_req_read_regs *req, unsigned int count,
+		       bool *retry)
+{
+	int r;
+	int i;
+	struct zd_usb_interrupt *intr = &usb->intr;
+	struct read_regs_int *rr = &intr->read_regs;
+	struct usb_int_regs *regs = (struct usb_int_regs *)rr->buffer;
+
+	spin_lock_irq(&intr->lock);
+
+	r = -EIO;
+
+	/* Read failed because firmware bug? */
+	*retry = !!intr->read_regs_int_overridden;
+	if (*retry)
+		goto error_unlock;
+
+	if (!check_read_regs(usb, req, count)) {
+		dev_dbg_f(zd_usb_dev(usb), "error: invalid read regs\n");
+		goto error_unlock;
+	}
+
+	for (i = 0; i < count; i++) {
+		struct reg_data *rd = &regs->regs[i];
+		values[i] = le16_to_cpu(rd->value);
+	}
+
+	r = 0;
+error_unlock:
+	spin_unlock_irq(&intr->lock);
+	return r;
+}
+
+int zd_usb_ioread16v(struct zd_usb *usb, u16 *values,
+	             const zd_addr_t *addresses, unsigned int count)
+{
+	int r, i, req_len, actual_req_len, try_count = 0;
+	struct usb_device *udev;
+	struct usb_req_read_regs *req = NULL;
+	unsigned long timeout;
+	bool retry = false;
+
+	if (count < 1) {
+		dev_dbg_f(zd_usb_dev(usb), "error: count is zero\n");
+		return -EINVAL;
+	}
+	if (count > USB_MAX_IOREAD16_COUNT) {
+		dev_dbg_f(zd_usb_dev(usb),
+			 "error: count %u exceeds possible max %u\n",
+			 count, USB_MAX_IOREAD16_COUNT);
+		return -EINVAL;
+	}
+	if (in_atomic()) {
+		dev_dbg_f(zd_usb_dev(usb),
+			 "error: io in atomic context not supported\n");
+		return -EWOULDBLOCK;
+	}
+	if (!usb_int_enabled(usb)) {
+		dev_dbg_f(zd_usb_dev(usb),
+			  "error: usb interrupt not enabled\n");
+		return -EWOULDBLOCK;
+	}
+
+	ZD_ASSERT(mutex_is_locked(&zd_usb_to_chip(usb)->mutex));
+	BUILD_BUG_ON(sizeof(struct usb_req_read_regs) + USB_MAX_IOREAD16_COUNT *
+		     sizeof(__le16) > sizeof(usb->req_buf));
+	BUG_ON(sizeof(struct usb_req_read_regs) + count * sizeof(__le16) >
+	       sizeof(usb->req_buf));
+
+	req_len = sizeof(struct usb_req_read_regs) + count * sizeof(__le16);
+	req = (void *)usb->req_buf;
+
+	req->id = cpu_to_le16(USB_REQ_READ_REGS);
+	for (i = 0; i < count; i++)
+		req->addr[i] = cpu_to_le16((u16)addresses[i]);
+
+retry_read:
+	try_count++;
+	udev = zd_usb_to_usbdev(usb);
+	prepare_read_regs_int(usb, req, count);
+	r = zd_ep_regs_out_msg(udev, req, req_len, &actual_req_len, 50 /*ms*/);
+	if (r) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error in zd_ep_regs_out_msg(). Error number %d\n", r);
+		goto error;
+	}
+	if (req_len != actual_req_len) {
+		dev_dbg_f(zd_usb_dev(usb), "error in zd_ep_regs_out_msg()\n"
+			" req_len %d != actual_req_len %d\n",
+			req_len, actual_req_len);
+		r = -EIO;
+		goto error;
+	}
+
+	timeout = wait_for_completion_timeout(&usb->intr.read_regs.completion,
+					      msecs_to_jiffies(50));
+	if (!timeout) {
+		disable_read_regs_int(usb);
+		dev_dbg_f(zd_usb_dev(usb), "read timed out\n");
+		r = -ETIMEDOUT;
+		goto error;
+	}
+
+	r = get_results(usb, values, req, count, &retry);
+	if (retry && try_count < 20) {
+		dev_dbg_f(zd_usb_dev(usb), "read retry, tries so far: %d\n",
+				try_count);
+		goto retry_read;
+	}
+error:
+	return r;
+}
+
+static void iowrite16v_urb_complete(struct urb *urb)
+{
+	struct zd_usb *usb = urb->context;
+
+	if (urb->status && !usb->cmd_error)
+		usb->cmd_error = urb->status;
+
+	if (!usb->cmd_error &&
+			urb->actual_length != urb->transfer_buffer_length)
+		usb->cmd_error = -EIO;
+}
+
+static int zd_submit_waiting_urb(struct zd_usb *usb, bool last)
+{
+	int r = 0;
+	struct urb *urb = usb->urb_async_waiting;
+
+	if (!urb)
+		return 0;
+
+	usb->urb_async_waiting = NULL;
+
+	if (!last)
+		urb->transfer_flags |= URB_NO_INTERRUPT;
+
+	usb_anchor_urb(urb, &usb->submitted_cmds);
+	r = usb_submit_urb(urb, GFP_KERNEL);
+	if (r) {
+		usb_unanchor_urb(urb);
+		dev_dbg_f(zd_usb_dev(usb),
+			"error in usb_submit_urb(). Error number %d\n", r);
+		goto error;
+	}
+
+	/* fall-through with r == 0 */
+error:
+	usb_free_urb(urb);
+	return r;
+}
+
+void zd_usb_iowrite16v_async_start(struct zd_usb *usb)
+{
+	ZD_ASSERT(usb_anchor_empty(&usb->submitted_cmds));
+	ZD_ASSERT(usb->urb_async_waiting == NULL);
+	ZD_ASSERT(!usb->in_async);
+
+	ZD_ASSERT(mutex_is_locked(&zd_usb_to_chip(usb)->mutex));
+
+	usb->in_async = 1;
+	usb->cmd_error = 0;
+	usb->urb_async_waiting = NULL;
+}
+
+int zd_usb_iowrite16v_async_end(struct zd_usb *usb, unsigned int timeout)
+{
+	int r;
+
+	ZD_ASSERT(mutex_is_locked(&zd_usb_to_chip(usb)->mutex));
+	ZD_ASSERT(usb->in_async);
+
+	/* Submit last iowrite16v URB */
+	r = zd_submit_waiting_urb(usb, true);
+	if (r) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error in zd_submit_waiting_usb(). "
+			"Error number %d\n", r);
+
+		usb_kill_anchored_urbs(&usb->submitted_cmds);
+		goto error;
+	}
+
+	if (timeout)
+		timeout = usb_wait_anchor_empty_timeout(&usb->submitted_cmds,
+							timeout);
+	if (!timeout) {
+		usb_kill_anchored_urbs(&usb->submitted_cmds);
+		if (usb->cmd_error == -ENOENT) {
+			dev_dbg_f(zd_usb_dev(usb), "timed out");
+			r = -ETIMEDOUT;
+			goto error;
+		}
+	}
+
+	r = usb->cmd_error;
+error:
+	usb->in_async = 0;
+	return r;
+}
+
+int zd_usb_iowrite16v_async(struct zd_usb *usb, const struct zd_ioreq16 *ioreqs,
+			    unsigned int count)
+{
+	int r;
+	struct usb_device *udev;
+	struct usb_req_write_regs *req = NULL;
+	int i, req_len;
+	struct urb *urb;
+	struct usb_host_endpoint *ep;
+
+	ZD_ASSERT(mutex_is_locked(&zd_usb_to_chip(usb)->mutex));
+	ZD_ASSERT(usb->in_async);
+
+	if (count == 0)
+		return 0;
+	if (count > USB_MAX_IOWRITE16_COUNT) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error: count %u exceeds possible max %u\n",
+			count, USB_MAX_IOWRITE16_COUNT);
+		return -EINVAL;
+	}
+	if (in_atomic()) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error: io in atomic context not supported\n");
+		return -EWOULDBLOCK;
+	}
+
+	udev = zd_usb_to_usbdev(usb);
+
+	ep = usb_pipe_endpoint(udev, usb_sndintpipe(udev, EP_REGS_OUT));
+	if (!ep)
+		return -ENOENT;
+
+	urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!urb)
+		return -ENOMEM;
+
+	req_len = struct_size(req, reg_writes, count);
+	req = kmalloc(req_len, GFP_KERNEL);
+	if (!req) {
+		r = -ENOMEM;
+		goto error;
+	}
+
+	req->id = cpu_to_le16(USB_REQ_WRITE_REGS);
+	for (i = 0; i < count; i++) {
+		struct reg_data *rw  = &req->reg_writes[i];
+		rw->addr = cpu_to_le16((u16)ioreqs[i].addr);
+		rw->value = cpu_to_le16(ioreqs[i].value);
+	}
+
+	/* In USB 2.0 mode endpoint is interrupt type. However in USB 1.1 mode
+	 * endpoint is bulk. Select correct type URB by endpoint descriptor.
+	 */
+	if (usb_endpoint_xfer_int(&ep->desc))
+		usb_fill_int_urb(urb, udev, usb_sndintpipe(udev, EP_REGS_OUT),
+				 req, req_len, iowrite16v_urb_complete, usb,
+				 ep->desc.bInterval);
+	else
+		usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_REGS_OUT),
+				  req, req_len, iowrite16v_urb_complete, usb);
+
+	urb->transfer_flags |= URB_FREE_BUFFER;
+
+	/* Submit previous URB */
+	r = zd_submit_waiting_urb(usb, false);
+	if (r) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error in zd_submit_waiting_usb(). "
+			"Error number %d\n", r);
+		goto error;
+	}
+
+	/* Delay submit so that URB_NO_INTERRUPT flag can be set for all URBs
+	 * of currect batch except for very last.
+	 */
+	usb->urb_async_waiting = urb;
+	return 0;
+error:
+	usb_free_urb(urb);
+	return r;
+}
+
+int zd_usb_iowrite16v(struct zd_usb *usb, const struct zd_ioreq16 *ioreqs,
+			unsigned int count)
+{
+	int r;
+
+	zd_usb_iowrite16v_async_start(usb);
+	r = zd_usb_iowrite16v_async(usb, ioreqs, count);
+	if (r) {
+		zd_usb_iowrite16v_async_end(usb, 0);
+		return r;
+	}
+	return zd_usb_iowrite16v_async_end(usb, 50 /* ms */);
+}
+
+int zd_usb_rfwrite(struct zd_usb *usb, u32 value, u8 bits)
+{
+	int r;
+	struct usb_device *udev;
+	struct usb_req_rfwrite *req = NULL;
+	int i, req_len, actual_req_len;
+	u16 bit_value_template;
+
+	if (in_atomic()) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error: io in atomic context not supported\n");
+		return -EWOULDBLOCK;
+	}
+	if (bits < USB_MIN_RFWRITE_BIT_COUNT) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error: bits %d are smaller than"
+			" USB_MIN_RFWRITE_BIT_COUNT %d\n",
+			bits, USB_MIN_RFWRITE_BIT_COUNT);
+		return -EINVAL;
+	}
+	if (bits > USB_MAX_RFWRITE_BIT_COUNT) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error: bits %d exceed USB_MAX_RFWRITE_BIT_COUNT %d\n",
+			bits, USB_MAX_RFWRITE_BIT_COUNT);
+		return -EINVAL;
+	}
+#ifdef DEBUG
+	if (value & (~0UL << bits)) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error: value %#09x has bits >= %d set\n",
+			value, bits);
+		return -EINVAL;
+	}
+#endif /* DEBUG */
+
+	dev_dbg_f(zd_usb_dev(usb), "value %#09x bits %d\n", value, bits);
+
+	r = zd_usb_ioread16(usb, &bit_value_template, ZD_CR203);
+	if (r) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error %d: Couldn't read ZD_CR203\n", r);
+		return r;
+	}
+	bit_value_template &= ~(RF_IF_LE|RF_CLK|RF_DATA);
+
+	ZD_ASSERT(mutex_is_locked(&zd_usb_to_chip(usb)->mutex));
+	BUILD_BUG_ON(sizeof(struct usb_req_rfwrite) +
+		     USB_MAX_RFWRITE_BIT_COUNT * sizeof(__le16) >
+		     sizeof(usb->req_buf));
+	BUG_ON(sizeof(struct usb_req_rfwrite) + bits * sizeof(__le16) >
+	       sizeof(usb->req_buf));
+
+	req_len = sizeof(struct usb_req_rfwrite) + bits * sizeof(__le16);
+	req = (void *)usb->req_buf;
+
+	req->id = cpu_to_le16(USB_REQ_WRITE_RF);
+	/* 1: 3683a, but not used in ZYDAS driver */
+	req->value = cpu_to_le16(2);
+	req->bits = cpu_to_le16(bits);
+
+	for (i = 0; i < bits; i++) {
+		u16 bv = bit_value_template;
+		if (value & (1 << (bits-1-i)))
+			bv |= RF_DATA;
+		req->bit_values[i] = cpu_to_le16(bv);
+	}
+
+	udev = zd_usb_to_usbdev(usb);
+	r = zd_ep_regs_out_msg(udev, req, req_len, &actual_req_len, 50 /*ms*/);
+	if (r) {
+		dev_dbg_f(zd_usb_dev(usb),
+			"error in zd_ep_regs_out_msg(). Error number %d\n", r);
+		goto out;
+	}
+	if (req_len != actual_req_len) {
+		dev_dbg_f(zd_usb_dev(usb), "error in zd_ep_regs_out_msg()"
+			" req_len %d != actual_req_len %d\n",
+			req_len, actual_req_len);
+		r = -EIO;
+		goto out;
+	}
+
+	/* FALL-THROUGH with r == 0 */
+out:
+	return r;
+}