usb: chipidea: split the driver code into units

Split the driver into the following parts:
  * core  -- resources, register access, capabilities, etc;
  * udc   -- device controller functionality;
  * debug -- logging events.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 804 insertions, 0 deletions

diff --git a/drivers/usb/chipidea/debug.c b/drivers/usb/chipidea/debug.c
new file mode 100644
index 00000000000..c4b3e15532d
--- /dev/null
+++ b/drivers/usb/chipidea/debug.c
@@ -0,0 +1,804 @@
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dmapool.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/pm_runtime.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/otg.h>
+#include <linux/usb/chipidea.h>
+
+#include "ci.h"
+#include "udc.h"
+#include "bits.h"
+#include "debug.h"
+
+/* Interrupt statistics */
+#define ISR_MASK   0x1F
+static struct isr_statistics {
+	u32 test;
+	u32 ui;
+	u32 uei;
+	u32 pci;
+	u32 uri;
+	u32 sli;
+	u32 none;
+	struct {
+		u32 cnt;
+		u32 buf[ISR_MASK+1];
+		u32 idx;
+	} hndl;
+} isr_statistics;
+
+void dbg_interrupt(u32 intmask)
+{
+	if (!intmask) {
+		isr_statistics.none++;
+		return;
+	}
+
+	isr_statistics.hndl.buf[isr_statistics.hndl.idx++] = intmask;
+	isr_statistics.hndl.idx &= ISR_MASK;
+	isr_statistics.hndl.cnt++;
+
+	if (USBi_URI & intmask)
+		isr_statistics.uri++;
+	if (USBi_PCI & intmask)
+		isr_statistics.pci++;
+	if (USBi_UEI & intmask)
+		isr_statistics.uei++;
+	if (USBi_UI  & intmask)
+		isr_statistics.ui++;
+	if (USBi_SLI & intmask)
+		isr_statistics.sli++;
+}
+
+/**
+ * hw_register_read: reads all device registers (execute without interruption)
+ * @buf:  destination buffer
+ * @size: buffer size
+ *
+ * This function returns number of registers read
+ */
+static size_t hw_register_read(struct ci13xxx *udc, u32 *buf, size_t size)
+{
+	unsigned i;
+
+	if (size > udc->hw_bank.size)
+		size = udc->hw_bank.size;
+
+	for (i = 0; i < size; i++)
+		buf[i] = hw_read(udc, i * sizeof(u32), ~0);
+
+	return size;
+}
+
+/**
+ * hw_register_write: writes to register
+ * @addr: register address
+ * @data: register value
+ *
+ * This function returns an error code
+ */
+static int hw_register_write(struct ci13xxx *udc, u16 addr, u32 data)
+{
+	/* align */
+	addr /= sizeof(u32);
+
+	if (addr >= udc->hw_bank.size)
+		return -EINVAL;
+
+	/* align */
+	addr *= sizeof(u32);
+
+	hw_write(udc, addr, ~0, data);
+	return 0;
+}
+
+/**
+ * hw_intr_clear: disables interrupt & clears interrupt status (execute without
+ *                interruption)
+ * @n: interrupt bit
+ *
+ * This function returns an error code
+ */
+static int hw_intr_clear(struct ci13xxx *udc, int n)
+{
+	if (n >= REG_BITS)
+		return -EINVAL;
+
+	hw_write(udc, OP_USBINTR, BIT(n), 0);
+	hw_write(udc, OP_USBSTS,  BIT(n), BIT(n));
+	return 0;
+}
+
+/**
+ * hw_intr_force: enables interrupt & forces interrupt status (execute without
+ *                interruption)
+ * @n: interrupt bit
+ *
+ * This function returns an error code
+ */
+static int hw_intr_force(struct ci13xxx *udc, int n)
+{
+	if (n >= REG_BITS)
+		return -EINVAL;
+
+	hw_write(udc, CAP_TESTMODE, TESTMODE_FORCE, TESTMODE_FORCE);
+	hw_write(udc, OP_USBINTR,  BIT(n), BIT(n));
+	hw_write(udc, OP_USBSTS,   BIT(n), BIT(n));
+	hw_write(udc, CAP_TESTMODE, TESTMODE_FORCE, 0);
+	return 0;
+}
+
+/**
+ * show_device: prints information about device capabilities and status
+ *
+ * Check "device.h" for details
+ */
+static ssize_t show_device(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct ci13xxx *udc = container_of(dev, struct ci13xxx, gadget.dev);
+	struct usb_gadget *gadget = &udc->gadget;
+	int n = 0;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(udc->dev, "[%s] EINVAL\n", __func__);
+		return 0;
+	}
+
+	n += scnprintf(buf + n, PAGE_SIZE - n, "speed             = %d\n",
+		       gadget->speed);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "max_speed         = %d\n",
+		       gadget->max_speed);
+	/* TODO: Scheduled for removal in 3.8. */
+	n += scnprintf(buf + n, PAGE_SIZE - n, "is_dualspeed      = %d\n",
+		       gadget_is_dualspeed(gadget));
+	n += scnprintf(buf + n, PAGE_SIZE - n, "is_otg            = %d\n",
+		       gadget->is_otg);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "is_a_peripheral   = %d\n",
+		       gadget->is_a_peripheral);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "b_hnp_enable      = %d\n",
+		       gadget->b_hnp_enable);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "a_hnp_support     = %d\n",
+		       gadget->a_hnp_support);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "a_alt_hnp_support = %d\n",
+		       gadget->a_alt_hnp_support);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "name              = %s\n",
+		       (gadget->name ? gadget->name : ""));
+
+	return n;
+}
+static DEVICE_ATTR(device, S_IRUSR, show_device, NULL);
+
+/**
+ * show_driver: prints information about attached gadget (if any)
+ *
+ * Check "device.h" for details
+ */
+static ssize_t show_driver(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct ci13xxx *udc = container_of(dev, struct ci13xxx, gadget.dev);
+	struct usb_gadget_driver *driver = udc->driver;
+	int n = 0;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(dev, "[%s] EINVAL\n", __func__);
+		return 0;
+	}
+
+	if (driver == NULL)
+		return scnprintf(buf, PAGE_SIZE,
+				 "There is no gadget attached!\n");
+
+	n += scnprintf(buf + n, PAGE_SIZE - n, "function  = %s\n",
+		       (driver->function ? driver->function : ""));
+	n += scnprintf(buf + n, PAGE_SIZE - n, "max speed = %d\n",
+		       driver->max_speed);
+
+	return n;
+}
+static DEVICE_ATTR(driver, S_IRUSR, show_driver, NULL);
+
+/* Maximum event message length */
+#define DBG_DATA_MSG   64UL
+
+/* Maximum event messages */
+#define DBG_DATA_MAX   128UL
+
+/* Event buffer descriptor */
+static struct {
+	char     (buf[DBG_DATA_MAX])[DBG_DATA_MSG];   /* buffer */
+	unsigned idx;   /* index */
+	unsigned tty;   /* print to console? */
+	rwlock_t lck;   /* lock */
+} dbg_data = {
+	.idx = 0,
+	.tty = 0,
+	.lck = __RW_LOCK_UNLOCKED(lck)
+};
+
+/**
+ * dbg_dec: decrements debug event index
+ * @idx: buffer index
+ */
+static void dbg_dec(unsigned *idx)
+{
+	*idx = (*idx - 1) & (DBG_DATA_MAX-1);
+}
+
+/**
+ * dbg_inc: increments debug event index
+ * @idx: buffer index
+ */
+static void dbg_inc(unsigned *idx)
+{
+	*idx = (*idx + 1) & (DBG_DATA_MAX-1);
+}
+
+/**
+ * dbg_print:  prints the common part of the event
+ * @addr:   endpoint address
+ * @name:   event name
+ * @status: status
+ * @extra:  extra information
+ */
+static void dbg_print(u8 addr, const char *name, int status, const char *extra)
+{
+	struct timeval tval;
+	unsigned int stamp;
+	unsigned long flags;
+
+	write_lock_irqsave(&dbg_data.lck, flags);
+
+	do_gettimeofday(&tval);
+	stamp = tval.tv_sec & 0xFFFF;	/* 2^32 = 4294967296. Limit to 4096s */
+	stamp = stamp * 1000000 + tval.tv_usec;
+
+	scnprintf(dbg_data.buf[dbg_data.idx], DBG_DATA_MSG,
+		  "%04X\t? %02X %-7.7s %4i ?\t%s\n",
+		  stamp, addr, name, status, extra);
+
+	dbg_inc(&dbg_data.idx);
+
+	write_unlock_irqrestore(&dbg_data.lck, flags);
+
+	if (dbg_data.tty != 0)
+		pr_notice("%04X\t? %02X %-7.7s %4i ?\t%s\n",
+			  stamp, addr, name, status, extra);
+}
+
+/**
+ * dbg_done: prints a DONE event
+ * @addr:   endpoint address
+ * @td:     transfer descriptor
+ * @status: status
+ */
+void dbg_done(u8 addr, const u32 token, int status)
+{
+	char msg[DBG_DATA_MSG];
+
+	scnprintf(msg, sizeof(msg), "%d %02X",
+		  (int)(token & TD_TOTAL_BYTES) >> ffs_nr(TD_TOTAL_BYTES),
+		  (int)(token & TD_STATUS)      >> ffs_nr(TD_STATUS));
+	dbg_print(addr, "DONE", status, msg);
+}
+
+/**
+ * dbg_event: prints a generic event
+ * @addr:   endpoint address
+ * @name:   event name
+ * @status: status
+ */
+void dbg_event(u8 addr, const char *name, int status)
+{
+	if (name != NULL)
+		dbg_print(addr, name, status, "");
+}
+
+/*
+ * dbg_queue: prints a QUEUE event
+ * @addr:   endpoint address
+ * @req:    USB request
+ * @status: status
+ */
+void dbg_queue(u8 addr, const struct usb_request *req, int status)
+{
+	char msg[DBG_DATA_MSG];
+
+	if (req != NULL) {
+		scnprintf(msg, sizeof(msg),
+			  "%d %d", !req->no_interrupt, req->length);
+		dbg_print(addr, "QUEUE", status, msg);
+	}
+}
+
+/**
+ * dbg_setup: prints a SETUP event
+ * @addr: endpoint address
+ * @req:  setup request
+ */
+void dbg_setup(u8 addr, const struct usb_ctrlrequest *req)
+{
+	char msg[DBG_DATA_MSG];
+
+	if (req != NULL) {
+		scnprintf(msg, sizeof(msg),
+			  "%02X %02X %04X %04X %d", req->bRequestType,
+			  req->bRequest, le16_to_cpu(req->wValue),
+			  le16_to_cpu(req->wIndex), le16_to_cpu(req->wLength));
+		dbg_print(addr, "SETUP", 0, msg);
+	}
+}
+
+/**
+ * show_events: displays the event buffer
+ *
+ * Check "device.h" for details
+ */
+static ssize_t show_events(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	unsigned long flags;
+	unsigned i, j, n = 0;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(dev->parent, "[%s] EINVAL\n", __func__);
+		return 0;
+	}
+
+	read_lock_irqsave(&dbg_data.lck, flags);
+
+	i = dbg_data.idx;
+	for (dbg_dec(&i); i != dbg_data.idx; dbg_dec(&i)) {
+		n += strlen(dbg_data.buf[i]);
+		if (n >= PAGE_SIZE) {
+			n -= strlen(dbg_data.buf[i]);
+			break;
+		}
+	}
+	for (j = 0, dbg_inc(&i); j < n; dbg_inc(&i))
+		j += scnprintf(buf + j, PAGE_SIZE - j,
+			       "%s", dbg_data.buf[i]);
+
+	read_unlock_irqrestore(&dbg_data.lck, flags);
+
+	return n;
+}
+
+/**
+ * store_events: configure if events are going to be also printed to console
+ *
+ * Check "device.h" for details
+ */
+static ssize_t store_events(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	unsigned tty;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(dev, "[%s] EINVAL\n", __func__);
+		goto done;
+	}
+
+	if (sscanf(buf, "%u", &tty) != 1 || tty > 1) {
+		dev_err(dev, "<1|0>: enable|disable console log\n");
+		goto done;
+	}
+
+	dbg_data.tty = tty;
+	dev_info(dev, "tty = %u", dbg_data.tty);
+
+ done:
+	return count;
+}
+static DEVICE_ATTR(events, S_IRUSR | S_IWUSR, show_events, store_events);
+
+/**
+ * show_inters: interrupt status, enable status and historic
+ *
+ * Check "device.h" for details
+ */
+static ssize_t show_inters(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct ci13xxx *udc = container_of(dev, struct ci13xxx, gadget.dev);
+	unsigned long flags;
+	u32 intr;
+	unsigned i, j, n = 0;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(udc->dev, "[%s] EINVAL\n", __func__);
+		return 0;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	/*n += scnprintf(buf + n, PAGE_SIZE - n,
+		       "status = %08x\n", hw_read_intr_status(udc));
+	n += scnprintf(buf + n, PAGE_SIZE - n,
+	"enable = %08x\n", hw_read_intr_enable(udc));*/
+
+	n += scnprintf(buf + n, PAGE_SIZE - n, "*test = %d\n",
+		       isr_statistics.test);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "? ui  = %d\n",
+		       isr_statistics.ui);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "? uei = %d\n",
+		       isr_statistics.uei);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "? pci = %d\n",
+		       isr_statistics.pci);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "? uri = %d\n",
+		       isr_statistics.uri);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "? sli = %d\n",
+		       isr_statistics.sli);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "*none = %d\n",
+		       isr_statistics.none);
+	n += scnprintf(buf + n, PAGE_SIZE - n, "*hndl = %d\n",
+		       isr_statistics.hndl.cnt);
+
+	for (i = isr_statistics.hndl.idx, j = 0; j <= ISR_MASK; j++, i++) {
+		i   &= ISR_MASK;
+		intr = isr_statistics.hndl.buf[i];
+
+		if (USBi_UI  & intr)
+			n += scnprintf(buf + n, PAGE_SIZE - n, "ui  ");
+		intr &= ~USBi_UI;
+		if (USBi_UEI & intr)
+			n += scnprintf(buf + n, PAGE_SIZE - n, "uei ");
+		intr &= ~USBi_UEI;
+		if (USBi_PCI & intr)
+			n += scnprintf(buf + n, PAGE_SIZE - n, "pci ");
+		intr &= ~USBi_PCI;
+		if (USBi_URI & intr)
+			n += scnprintf(buf + n, PAGE_SIZE - n, "uri ");
+		intr &= ~USBi_URI;
+		if (USBi_SLI & intr)
+			n += scnprintf(buf + n, PAGE_SIZE - n, "sli ");
+		intr &= ~USBi_SLI;
+		if (intr)
+			n += scnprintf(buf + n, PAGE_SIZE - n, "??? ");
+		if (isr_statistics.hndl.buf[i])
+			n += scnprintf(buf + n, PAGE_SIZE - n, "\n");
+	}
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return n;
+}
+
+/**
+ * store_inters: enable & force or disable an individual interrutps
+ *                   (to be used for test purposes only)
+ *
+ * Check "device.h" for details
+ */
+static ssize_t store_inters(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct ci13xxx *udc = container_of(dev, struct ci13xxx, gadget.dev);
+	unsigned long flags;
+	unsigned en, bit;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(udc->dev, "EINVAL\n");
+		goto done;
+	}
+
+	if (sscanf(buf, "%u %u", &en, &bit) != 2 || en > 1) {
+		dev_err(udc->dev, "<1|0> <bit>: enable|disable interrupt\n");
+		goto done;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+	if (en) {
+		if (hw_intr_force(udc, bit))
+			dev_err(dev, "invalid bit number\n");
+		else
+			isr_statistics.test++;
+	} else {
+		if (hw_intr_clear(udc, bit))
+			dev_err(dev, "invalid bit number\n");
+	}
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+ done:
+	return count;
+}
+static DEVICE_ATTR(inters, S_IRUSR | S_IWUSR, show_inters, store_inters);
+
+/**
+ * show_port_test: reads port test mode
+ *
+ * Check "device.h" for details
+ */
+static ssize_t show_port_test(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct ci13xxx *udc = container_of(dev, struct ci13xxx, gadget.dev);
+	unsigned long flags;
+	unsigned mode;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(udc->dev, "EINVAL\n");
+		return 0;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+	mode = hw_port_test_get(udc);
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return scnprintf(buf, PAGE_SIZE, "mode = %u\n", mode);
+}
+
+/**
+ * store_port_test: writes port test mode
+ *
+ * Check "device.h" for details
+ */
+static ssize_t store_port_test(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct ci13xxx *udc = container_of(dev, struct ci13xxx, gadget.dev);
+	unsigned long flags;
+	unsigned mode;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(udc->dev, "[%s] EINVAL\n", __func__);
+		goto done;
+	}
+
+	if (sscanf(buf, "%u", &mode) != 1) {
+		dev_err(udc->dev, "<mode>: set port test mode");
+		goto done;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+	if (hw_port_test_set(udc, mode))
+		dev_err(udc->dev, "invalid mode\n");
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+ done:
+	return count;
+}
+static DEVICE_ATTR(port_test, S_IRUSR | S_IWUSR,
+		   show_port_test, store_port_test);
+
+/**
+ * show_qheads: DMA contents of all queue heads
+ *
+ * Check "device.h" for details
+ */
+static ssize_t show_qheads(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct ci13xxx *udc = container_of(dev, struct ci13xxx, gadget.dev);
+	unsigned long flags;
+	unsigned i, j, n = 0;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(udc->dev, "[%s] EINVAL\n", __func__);
+		return 0;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+	for (i = 0; i < udc->hw_ep_max/2; i++) {
+		struct ci13xxx_ep *mEpRx = &udc->ci13xxx_ep[i];
+		struct ci13xxx_ep *mEpTx =
+			&udc->ci13xxx_ep[i + udc->hw_ep_max/2];
+		n += scnprintf(buf + n, PAGE_SIZE - n,
+			       "EP=%02i: RX=%08X TX=%08X\n",
+			       i, (u32)mEpRx->qh.dma, (u32)mEpTx->qh.dma);
+		for (j = 0; j < (sizeof(struct ci13xxx_qh)/sizeof(u32)); j++) {
+			n += scnprintf(buf + n, PAGE_SIZE - n,
+				       " %04X:    %08X    %08X\n", j,
+				       *((u32 *)mEpRx->qh.ptr + j),
+				       *((u32 *)mEpTx->qh.ptr + j));
+		}
+	}
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return n;
+}
+static DEVICE_ATTR(qheads, S_IRUSR, show_qheads, NULL);
+
+/**
+ * show_registers: dumps all registers
+ *
+ * Check "device.h" for details
+ */
+#define DUMP_ENTRIES	512
+static ssize_t show_registers(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct ci13xxx *udc = container_of(dev, struct ci13xxx, gadget.dev);
+	unsigned long flags;
+	u32 *dump;
+	unsigned i, k, n = 0;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(udc->dev, "[%s] EINVAL\n", __func__);
+		return 0;
+	}
+
+	dump = kmalloc(sizeof(u32) * DUMP_ENTRIES, GFP_KERNEL);
+	if (!dump) {
+		dev_err(udc->dev, "%s: out of memory\n", __func__);
+		return 0;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+	k = hw_register_read(udc, dump, DUMP_ENTRIES);
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	for (i = 0; i < k; i++) {
+		n += scnprintf(buf + n, PAGE_SIZE - n,
+			       "reg[0x%04X] = 0x%08X\n",
+			       i * (unsigned)sizeof(u32), dump[i]);
+	}
+	kfree(dump);
+
+	return n;
+}
+
+/**
+ * store_registers: writes value to register address
+ *
+ * Check "device.h" for details
+ */
+static ssize_t store_registers(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct ci13xxx *udc = container_of(dev, struct ci13xxx, gadget.dev);
+	unsigned long addr, data, flags;
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(udc->dev, "[%s] EINVAL\n", __func__);
+		goto done;
+	}
+
+	if (sscanf(buf, "%li %li", &addr, &data) != 2) {
+		dev_err(udc->dev,
+			"<addr> <data>: write data to register address\n");
+		goto done;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+	if (hw_register_write(udc, addr, data))
+		dev_err(udc->dev, "invalid address range\n");
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+ done:
+	return count;
+}
+static DEVICE_ATTR(registers, S_IRUSR | S_IWUSR,
+		   show_registers, store_registers);
+
+/**
+ * show_requests: DMA contents of all requests currently queued (all endpts)
+ *
+ * Check "device.h" for details
+ */
+static ssize_t show_requests(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct ci13xxx *udc = container_of(dev, struct ci13xxx, gadget.dev);
+	unsigned long flags;
+	struct list_head   *ptr = NULL;
+	struct ci13xxx_req *req = NULL;
+	unsigned i, j, n = 0, qSize = sizeof(struct ci13xxx_td)/sizeof(u32);
+
+	if (attr == NULL || buf == NULL) {
+		dev_err(udc->dev, "[%s] EINVAL\n", __func__);
+		return 0;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+	for (i = 0; i < udc->hw_ep_max; i++)
+		list_for_each(ptr, &udc->ci13xxx_ep[i].qh.queue)
+		{
+			req = list_entry(ptr, struct ci13xxx_req, queue);
+
+			n += scnprintf(buf + n, PAGE_SIZE - n,
+					"EP=%02i: TD=%08X %s\n",
+					i % udc->hw_ep_max/2, (u32)req->dma,
+					((i < udc->hw_ep_max/2) ? "RX" : "TX"));
+
+			for (j = 0; j < qSize; j++)
+				n += scnprintf(buf + n, PAGE_SIZE - n,
+						" %04X:    %08X\n", j,
+						*((u32 *)req->ptr + j));
+		}
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return n;
+}
+static DEVICE_ATTR(requests, S_IRUSR, show_requests, NULL);
+
+/**
+ * dbg_create_files: initializes the attribute interface
+ * @dev: device
+ *
+ * This function returns an error code
+ */
+int dbg_create_files(struct device *dev)
+{
+	int retval = 0;
+
+	if (dev == NULL)
+		return -EINVAL;
+	retval = device_create_file(dev, &dev_attr_device);
+	if (retval)
+		goto done;
+	retval = device_create_file(dev, &dev_attr_driver);
+	if (retval)
+		goto rm_device;
+	retval = device_create_file(dev, &dev_attr_events);
+	if (retval)
+		goto rm_driver;
+	retval = device_create_file(dev, &dev_attr_inters);
+	if (retval)
+		goto rm_events;
+	retval = device_create_file(dev, &dev_attr_port_test);
+	if (retval)
+		goto rm_inters;
+	retval = device_create_file(dev, &dev_attr_qheads);
+	if (retval)
+		goto rm_port_test;
+	retval = device_create_file(dev, &dev_attr_registers);
+	if (retval)
+		goto rm_qheads;
+	retval = device_create_file(dev, &dev_attr_requests);
+	if (retval)
+		goto rm_registers;
+	return 0;
+
+ rm_registers:
+	device_remove_file(dev, &dev_attr_registers);
+ rm_qheads:
+	device_remove_file(dev, &dev_attr_qheads);
+ rm_port_test:
+	device_remove_file(dev, &dev_attr_port_test);
+ rm_inters:
+	device_remove_file(dev, &dev_attr_inters);
+ rm_events:
+	device_remove_file(dev, &dev_attr_events);
+ rm_driver:
+	device_remove_file(dev, &dev_attr_driver);
+ rm_device:
+	device_remove_file(dev, &dev_attr_device);
+ done:
+	return retval;
+}
+
+/**
+ * dbg_remove_files: destroys the attribute interface
+ * @dev: device
+ *
+ * This function returns an error code
+ */
+int dbg_remove_files(struct device *dev)
+{
+	if (dev == NULL)
+		return -EINVAL;
+	device_remove_file(dev, &dev_attr_requests);
+	device_remove_file(dev, &dev_attr_registers);
+	device_remove_file(dev, &dev_attr_qheads);
+	device_remove_file(dev, &dev_attr_port_test);
+	device_remove_file(dev, &dev_attr_inters);
+	device_remove_file(dev, &dev_attr_events);
+	device_remove_file(dev, &dev_attr_driver);
+	device_remove_file(dev, &dev_attr_device);
+	return 0;
+}