USB: ehci,dbgp,early_printk: split ehci debug driver from early_printk.c

Move the dbgp early printk driver in advance of refactoring and adding
new code, so the changes to this code are tracked separately from the
move of the code.

The drivers/usb/early directory will be the location of the current
and future early usb code for driving usb devices prior initializing
the standard interrupt driven USB drivers.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 729 insertions, 0 deletions

diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile
index dbe4fb694ad2..be3c9b80bc9f 100644
--- a/drivers/usb/Makefile
+++ b/drivers/usb/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_USB_MICROTEK)	+= image/
 obj-$(CONFIG_USB_SERIAL)	+= serial/
 
 obj-$(CONFIG_USB)		+= misc/
+obj-y				+= early/
 
 obj-$(CONFIG_USB_ATM)		+= atm/
 obj-$(CONFIG_USB_SPEEDTOUCH)	+= atm/
diff --git a/drivers/usb/early/Makefile b/drivers/usb/early/Makefile
new file mode 100644
index 000000000000..dfedee8c45b6
--- /dev/null
+++ b/drivers/usb/early/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for early USB devices
+#
+
+obj-$(CONFIG_EARLY_PRINTK_DBGP)        += ehci-dbgp.o
diff --git a/drivers/usb/early/ehci-dbgp.c b/drivers/usb/early/ehci-dbgp.c
new file mode 100644
index 000000000000..821b7b21c29c
--- /dev/null
+++ b/drivers/usb/early/ehci-dbgp.c
@@ -0,0 +1,723 @@
+#include <linux/console.h>
+#include <linux/errno.h>
+#include <linux/pci_regs.h>
+#include <linux/pci_ids.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/ehci_def.h>
+#include <linux/delay.h>
+#include <asm/io.h>
+#include <asm/pci-direct.h>
+#include <asm/fixmap.h>
+
+static struct ehci_caps __iomem *ehci_caps;
+static struct ehci_regs __iomem *ehci_regs;
+static struct ehci_dbg_port __iomem *ehci_debug;
+static unsigned int dbgp_endpoint_out;
+
+struct ehci_dev {
+	u32 bus;
+	u32 slot;
+	u32 func;
+};
+
+static struct ehci_dev ehci_dev;
+
+#define USB_DEBUG_DEVNUM 127
+
+#define DBGP_DATA_TOGGLE	0x8800
+
+static inline u32 dbgp_pid_update(u32 x, u32 tok)
+{
+	return ((x ^ DBGP_DATA_TOGGLE) & 0xffff00) | (tok & 0xff);
+}
+
+static inline u32 dbgp_len_update(u32 x, u32 len)
+{
+	return (x & ~0x0f) | (len & 0x0f);
+}
+
+/*
+ * USB Packet IDs (PIDs)
+ */
+
+/* token */
+#define USB_PID_OUT		0xe1
+#define USB_PID_IN		0x69
+#define USB_PID_SOF		0xa5
+#define USB_PID_SETUP		0x2d
+/* handshake */
+#define USB_PID_ACK		0xd2
+#define USB_PID_NAK		0x5a
+#define USB_PID_STALL		0x1e
+#define USB_PID_NYET		0x96
+/* data */
+#define USB_PID_DATA0		0xc3
+#define USB_PID_DATA1		0x4b
+#define USB_PID_DATA2		0x87
+#define USB_PID_MDATA		0x0f
+/* Special */
+#define USB_PID_PREAMBLE	0x3c
+#define USB_PID_ERR		0x3c
+#define USB_PID_SPLIT		0x78
+#define USB_PID_PING		0xb4
+#define USB_PID_UNDEF_0		0xf0
+
+#define USB_PID_DATA_TOGGLE	0x88
+#define DBGP_CLAIM (DBGP_OWNER | DBGP_ENABLED | DBGP_INUSE)
+
+#define PCI_CAP_ID_EHCI_DEBUG	0xa
+
+#define HUB_ROOT_RESET_TIME	50	/* times are in msec */
+#define HUB_SHORT_RESET_TIME	10
+#define HUB_LONG_RESET_TIME	200
+#define HUB_RESET_TIMEOUT	500
+
+#define DBGP_MAX_PACKET		8
+
+static int dbgp_wait_until_complete(void)
+{
+	u32 ctrl;
+	int loop = 0x100000;
+
+	do {
+		ctrl = readl(&ehci_debug->control);
+		/* Stop when the transaction is finished */
+		if (ctrl & DBGP_DONE)
+			break;
+	} while (--loop > 0);
+
+	if (!loop)
+		return -1;
+
+	/*
+	 * Now that we have observed the completed transaction,
+	 * clear the done bit.
+	 */
+	writel(ctrl | DBGP_DONE, &ehci_debug->control);
+	return (ctrl & DBGP_ERROR) ? -DBGP_ERRCODE(ctrl) : DBGP_LEN(ctrl);
+}
+
+static void __init dbgp_mdelay(int ms)
+{
+	int i;
+
+	while (ms--) {
+		for (i = 0; i < 1000; i++)
+			outb(0x1, 0x80);
+	}
+}
+
+static void dbgp_breath(void)
+{
+	/* Sleep to give the debug port a chance to breathe */
+}
+
+static int dbgp_wait_until_done(unsigned ctrl)
+{
+	u32 pids, lpid;
+	int ret;
+	int loop = 3;
+
+retry:
+	writel(ctrl | DBGP_GO, &ehci_debug->control);
+	ret = dbgp_wait_until_complete();
+	pids = readl(&ehci_debug->pids);
+	lpid = DBGP_PID_GET(pids);
+
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * If the port is getting full or it has dropped data
+	 * start pacing ourselves, not necessary but it's friendly.
+	 */
+	if ((lpid == USB_PID_NAK) || (lpid == USB_PID_NYET))
+		dbgp_breath();
+
+	/* If I get a NACK reissue the transmission */
+	if (lpid == USB_PID_NAK) {
+		if (--loop > 0)
+			goto retry;
+	}
+
+	return ret;
+}
+
+static void dbgp_set_data(const void *buf, int size)
+{
+	const unsigned char *bytes = buf;
+	u32 lo, hi;
+	int i;
+
+	lo = hi = 0;
+	for (i = 0; i < 4 && i < size; i++)
+		lo |= bytes[i] << (8*i);
+	for (; i < 8 && i < size; i++)
+		hi |= bytes[i] << (8*(i - 4));
+	writel(lo, &ehci_debug->data03);
+	writel(hi, &ehci_debug->data47);
+}
+
+static void __init dbgp_get_data(void *buf, int size)
+{
+	unsigned char *bytes = buf;
+	u32 lo, hi;
+	int i;
+
+	lo = readl(&ehci_debug->data03);
+	hi = readl(&ehci_debug->data47);
+	for (i = 0; i < 4 && i < size; i++)
+		bytes[i] = (lo >> (8*i)) & 0xff;
+	for (; i < 8 && i < size; i++)
+		bytes[i] = (hi >> (8*(i - 4))) & 0xff;
+}
+
+static int dbgp_bulk_write(unsigned devnum, unsigned endpoint,
+			 const char *bytes, int size)
+{
+	u32 pids, addr, ctrl;
+	int ret;
+
+	if (size > DBGP_MAX_PACKET)
+		return -1;
+
+	addr = DBGP_EPADDR(devnum, endpoint);
+
+	pids = readl(&ehci_debug->pids);
+	pids = dbgp_pid_update(pids, USB_PID_OUT);
+
+	ctrl = readl(&ehci_debug->control);
+	ctrl = dbgp_len_update(ctrl, size);
+	ctrl |= DBGP_OUT;
+	ctrl |= DBGP_GO;
+
+	dbgp_set_data(bytes, size);
+	writel(addr, &ehci_debug->address);
+	writel(pids, &ehci_debug->pids);
+
+	ret = dbgp_wait_until_done(ctrl);
+	if (ret < 0)
+		return ret;
+
+	return ret;
+}
+
+static int __init dbgp_bulk_read(unsigned devnum, unsigned endpoint, void *data,
+				 int size)
+{
+	u32 pids, addr, ctrl;
+	int ret;
+
+	if (size > DBGP_MAX_PACKET)
+		return -1;
+
+	addr = DBGP_EPADDR(devnum, endpoint);
+
+	pids = readl(&ehci_debug->pids);
+	pids = dbgp_pid_update(pids, USB_PID_IN);
+
+	ctrl = readl(&ehci_debug->control);
+	ctrl = dbgp_len_update(ctrl, size);
+	ctrl &= ~DBGP_OUT;
+	ctrl |= DBGP_GO;
+
+	writel(addr, &ehci_debug->address);
+	writel(pids, &ehci_debug->pids);
+	ret = dbgp_wait_until_done(ctrl);
+	if (ret < 0)
+		return ret;
+
+	if (size > ret)
+		size = ret;
+	dbgp_get_data(data, size);
+	return ret;
+}
+
+static int __init dbgp_control_msg(unsigned devnum, int requesttype,
+	int request, int value, int index, void *data, int size)
+{
+	u32 pids, addr, ctrl;
+	struct usb_ctrlrequest req;
+	int read;
+	int ret;
+
+	read = (requesttype & USB_DIR_IN) != 0;
+	if (size > (read ? DBGP_MAX_PACKET:0))
+		return -1;
+
+	/* Compute the control message */
+	req.bRequestType = requesttype;
+	req.bRequest = request;
+	req.wValue = cpu_to_le16(value);
+	req.wIndex = cpu_to_le16(index);
+	req.wLength = cpu_to_le16(size);
+
+	pids = DBGP_PID_SET(USB_PID_DATA0, USB_PID_SETUP);
+	addr = DBGP_EPADDR(devnum, 0);
+
+	ctrl = readl(&ehci_debug->control);
+	ctrl = dbgp_len_update(ctrl, sizeof(req));
+	ctrl |= DBGP_OUT;
+	ctrl |= DBGP_GO;
+
+	/* Send the setup message */
+	dbgp_set_data(&req, sizeof(req));
+	writel(addr, &ehci_debug->address);
+	writel(pids, &ehci_debug->pids);
+	ret = dbgp_wait_until_done(ctrl);
+	if (ret < 0)
+		return ret;
+
+	/* Read the result */
+	return dbgp_bulk_read(devnum, 0, data, size);
+}
+
+
+/* Find a PCI capability */
+static u32 __init find_cap(u32 num, u32 slot, u32 func, int cap)
+{
+	u8 pos;
+	int bytes;
+
+	if (!(read_pci_config_16(num, slot, func, PCI_STATUS) &
+		PCI_STATUS_CAP_LIST))
+		return 0;
+
+	pos = read_pci_config_byte(num, slot, func, PCI_CAPABILITY_LIST);
+	for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {
+		u8 id;
+
+		pos &= ~3;
+		id = read_pci_config_byte(num, slot, func, pos+PCI_CAP_LIST_ID);
+		if (id == 0xff)
+			break;
+		if (id == cap)
+			return pos;
+
+		pos = read_pci_config_byte(num, slot, func,
+						 pos+PCI_CAP_LIST_NEXT);
+	}
+	return 0;
+}
+
+static u32 __init __find_dbgp(u32 bus, u32 slot, u32 func)
+{
+	u32 class;
+
+	class = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
+	if ((class >> 8) != PCI_CLASS_SERIAL_USB_EHCI)
+		return 0;
+
+	return find_cap(bus, slot, func, PCI_CAP_ID_EHCI_DEBUG);
+}
+
+static u32 __init find_dbgp(int ehci_num, u32 *rbus, u32 *rslot, u32 *rfunc)
+{
+	u32 bus, slot, func;
+
+	for (bus = 0; bus < 256; bus++) {
+		for (slot = 0; slot < 32; slot++) {
+			for (func = 0; func < 8; func++) {
+				unsigned cap;
+
+				cap = __find_dbgp(bus, slot, func);
+
+				if (!cap)
+					continue;
+				if (ehci_num-- != 0)
+					continue;
+				*rbus = bus;
+				*rslot = slot;
+				*rfunc = func;
+				return cap;
+			}
+		}
+	}
+	return 0;
+}
+
+static int __init ehci_reset_port(int port)
+{
+	u32 portsc;
+	u32 delay_time, delay;
+	int loop;
+
+	/* Reset the usb debug port */
+	portsc = readl(&ehci_regs->port_status[port - 1]);
+	portsc &= ~PORT_PE;
+	portsc |= PORT_RESET;
+	writel(portsc, &ehci_regs->port_status[port - 1]);
+
+	delay = HUB_ROOT_RESET_TIME;
+	for (delay_time = 0; delay_time < HUB_RESET_TIMEOUT;
+	     delay_time += delay) {
+		dbgp_mdelay(delay);
+
+		portsc = readl(&ehci_regs->port_status[port - 1]);
+		if (portsc & PORT_RESET) {
+			/* force reset to complete */
+			loop = 2;
+			writel(portsc & ~(PORT_RWC_BITS | PORT_RESET),
+				&ehci_regs->port_status[port - 1]);
+			do {
+				portsc = readl(&ehci_regs->port_status[port-1]);
+			} while ((portsc & PORT_RESET) && (--loop > 0));
+		}
+
+		/* Device went away? */
+		if (!(portsc & PORT_CONNECT))
+			return -ENOTCONN;
+
+		/* bomb out completely if something weird happend */
+		if ((portsc & PORT_CSC))
+			return -EINVAL;
+
+		/* If we've finished resetting, then break out of the loop */
+		if (!(portsc & PORT_RESET) && (portsc & PORT_PE))
+			return 0;
+	}
+	return -EBUSY;
+}
+
+static int __init ehci_wait_for_port(int port)
+{
+	u32 status;
+	int ret, reps;
+
+	for (reps = 0; reps < 3; reps++) {
+		dbgp_mdelay(100);
+		status = readl(&ehci_regs->status);
+		if (status & STS_PCD) {
+			ret = ehci_reset_port(port);
+			if (ret == 0)
+				return 0;
+		}
+	}
+	return -ENOTCONN;
+}
+
+#ifdef DBGP_DEBUG
+# define dbgp_printk early_printk
+#else
+static inline void dbgp_printk(const char *fmt, ...) { }
+#endif
+
+typedef void (*set_debug_port_t)(int port);
+
+static void __init default_set_debug_port(int port)
+{
+}
+
+static set_debug_port_t __initdata set_debug_port = default_set_debug_port;
+
+static void __init nvidia_set_debug_port(int port)
+{
+	u32 dword;
+	dword = read_pci_config(ehci_dev.bus, ehci_dev.slot, ehci_dev.func,
+				 0x74);
+	dword &= ~(0x0f<<12);
+	dword |= ((port & 0x0f)<<12);
+	write_pci_config(ehci_dev.bus, ehci_dev.slot, ehci_dev.func, 0x74,
+				 dword);
+	dbgp_printk("set debug port to %d\n", port);
+}
+
+static void __init detect_set_debug_port(void)
+{
+	u32 vendorid;
+
+	vendorid = read_pci_config(ehci_dev.bus, ehci_dev.slot, ehci_dev.func,
+		 0x00);
+
+	if ((vendorid & 0xffff) == 0x10de) {
+		dbgp_printk("using nvidia set_debug_port\n");
+		set_debug_port = nvidia_set_debug_port;
+	}
+}
+
+static int __init ehci_setup(void)
+{
+	struct usb_debug_descriptor dbgp_desc;
+	u32 cmd, ctrl, status, portsc, hcs_params;
+	u32 debug_port, new_debug_port = 0, n_ports;
+	u32  devnum;
+	int ret, i;
+	int loop;
+	int port_map_tried;
+	int playtimes = 3;
+
+try_next_time:
+	port_map_tried = 0;
+
+try_next_port:
+
+	hcs_params = readl(&ehci_caps->hcs_params);
+	debug_port = HCS_DEBUG_PORT(hcs_params);
+	n_ports    = HCS_N_PORTS(hcs_params);
+
+	dbgp_printk("debug_port: %d\n", debug_port);
+	dbgp_printk("n_ports:    %d\n", n_ports);
+
+	for (i = 1; i <= n_ports; i++) {
+		portsc = readl(&ehci_regs->port_status[i-1]);
+		dbgp_printk("portstatus%d: %08x\n", i, portsc);
+	}
+
+	if (port_map_tried && (new_debug_port != debug_port)) {
+		if (--playtimes) {
+			set_debug_port(new_debug_port);
+			goto try_next_time;
+		}
+		return -1;
+	}
+
+	loop = 100000;
+	/* Reset the EHCI controller */
+	cmd = readl(&ehci_regs->command);
+	cmd |= CMD_RESET;
+	writel(cmd, &ehci_regs->command);
+	do {
+		cmd = readl(&ehci_regs->command);
+	} while ((cmd & CMD_RESET) && (--loop > 0));
+
+	if (!loop) {
+		dbgp_printk("can not reset ehci\n");
+		return -1;
+	}
+	dbgp_printk("ehci reset done\n");
+
+	/* Claim ownership, but do not enable yet */
+	ctrl = readl(&ehci_debug->control);
+	ctrl |= DBGP_OWNER;
+	ctrl &= ~(DBGP_ENABLED | DBGP_INUSE);
+	writel(ctrl, &ehci_debug->control);
+
+	/* Start the ehci running */
+	cmd = readl(&ehci_regs->command);
+	cmd &= ~(CMD_LRESET | CMD_IAAD | CMD_PSE | CMD_ASE | CMD_RESET);
+	cmd |= CMD_RUN;
+	writel(cmd, &ehci_regs->command);
+
+	/* Ensure everything is routed to the EHCI */
+	writel(FLAG_CF, &ehci_regs->configured_flag);
+
+	/* Wait until the controller is no longer halted */
+	loop = 10;
+	do {
+		status = readl(&ehci_regs->status);
+	} while ((status & STS_HALT) && (--loop > 0));
+
+	if (!loop) {
+		dbgp_printk("ehci can be started\n");
+		return -1;
+	}
+	dbgp_printk("ehci started\n");
+
+	/* Wait for a device to show up in the debug port */
+	ret = ehci_wait_for_port(debug_port);
+	if (ret < 0) {
+		dbgp_printk("No device found in debug port\n");
+		goto next_debug_port;
+	}
+	dbgp_printk("ehci wait for port done\n");
+
+	/* Enable the debug port */
+	ctrl = readl(&ehci_debug->control);
+	ctrl |= DBGP_CLAIM;
+	writel(ctrl, &ehci_debug->control);
+	ctrl = readl(&ehci_debug->control);
+	if ((ctrl & DBGP_CLAIM) != DBGP_CLAIM) {
+		dbgp_printk("No device in debug port\n");
+		writel(ctrl & ~DBGP_CLAIM, &ehci_debug->control);
+		goto err;
+	}
+	dbgp_printk("debug ported enabled\n");
+
+	/* Completely transfer the debug device to the debug controller */
+	portsc = readl(&ehci_regs->port_status[debug_port - 1]);
+	portsc &= ~PORT_PE;
+	writel(portsc, &ehci_regs->port_status[debug_port - 1]);
+
+	dbgp_mdelay(100);
+
+	/* Find the debug device and make it device number 127 */
+	for (devnum = 0; devnum <= 127; devnum++) {
+		ret = dbgp_control_msg(devnum,
+			USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
+			USB_REQ_GET_DESCRIPTOR, (USB_DT_DEBUG << 8), 0,
+			&dbgp_desc, sizeof(dbgp_desc));
+		if (ret > 0)
+			break;
+	}
+	if (devnum > 127) {
+		dbgp_printk("Could not find attached debug device\n");
+		goto err;
+	}
+	if (ret < 0) {
+		dbgp_printk("Attached device is not a debug device\n");
+		goto err;
+	}
+	dbgp_endpoint_out = dbgp_desc.bDebugOutEndpoint;
+
+	/* Move the device to 127 if it isn't already there */
+	if (devnum != USB_DEBUG_DEVNUM) {
+		ret = dbgp_control_msg(devnum,
+			USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
+			USB_REQ_SET_ADDRESS, USB_DEBUG_DEVNUM, 0, NULL, 0);
+		if (ret < 0) {
+			dbgp_printk("Could not move attached device to %d\n",
+				USB_DEBUG_DEVNUM);
+			goto err;
+		}
+		devnum = USB_DEBUG_DEVNUM;
+		dbgp_printk("debug device renamed to 127\n");
+	}
+
+	/* Enable the debug interface */
+	ret = dbgp_control_msg(USB_DEBUG_DEVNUM,
+		USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
+		USB_REQ_SET_FEATURE, USB_DEVICE_DEBUG_MODE, 0, NULL, 0);
+	if (ret < 0) {
+		dbgp_printk(" Could not enable the debug device\n");
+		goto err;
+	}
+	dbgp_printk("debug interface enabled\n");
+
+	/* Perform a small write to get the even/odd data state in sync
+	 */
+	ret = dbgp_bulk_write(USB_DEBUG_DEVNUM, dbgp_endpoint_out, " ", 1);
+	if (ret < 0) {
+		dbgp_printk("dbgp_bulk_write failed: %d\n", ret);
+		goto err;
+	}
+	dbgp_printk("small write doned\n");
+
+	return 0;
+err:
+	/* Things didn't work so remove my claim */
+	ctrl = readl(&ehci_debug->control);
+	ctrl &= ~(DBGP_CLAIM | DBGP_OUT);
+	writel(ctrl, &ehci_debug->control);
+	return -1;
+
+next_debug_port:
+	port_map_tried |= (1<<(debug_port - 1));
+	new_debug_port = ((debug_port-1+1)%n_ports) + 1;
+	if (port_map_tried != ((1<<n_ports) - 1)) {
+		set_debug_port(new_debug_port);
+		goto try_next_port;
+	}
+	if (--playtimes) {
+		set_debug_port(new_debug_port);
+		goto try_next_time;
+	}
+
+	return -1;
+}
+
+int __init early_dbgp_init(char *s)
+{
+	u32 debug_port, bar, offset;
+	u32 bus, slot, func, cap;
+	void __iomem *ehci_bar;
+	u32 dbgp_num;
+	u32 bar_val;
+	char *e;
+	int ret;
+	u8 byte;
+
+	if (!early_pci_allowed())
+		return -1;
+
+	dbgp_num = 0;
+	if (*s)
+		dbgp_num = simple_strtoul(s, &e, 10);
+	dbgp_printk("dbgp_num: %d\n", dbgp_num);
+
+	cap = find_dbgp(dbgp_num, &bus, &slot, &func);
+	if (!cap)
+		return -1;
+
+	dbgp_printk("Found EHCI debug port on %02x:%02x.%1x\n", bus, slot,
+			 func);
+
+	debug_port = read_pci_config(bus, slot, func, cap);
+	bar = (debug_port >> 29) & 0x7;
+	bar = (bar * 4) + 0xc;
+	offset = (debug_port >> 16) & 0xfff;
+	dbgp_printk("bar: %02x offset: %03x\n", bar, offset);
+	if (bar != PCI_BASE_ADDRESS_0) {
+		dbgp_printk("only debug ports on bar 1 handled.\n");
+
+		return -1;
+	}
+
+	bar_val = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
+	dbgp_printk("bar_val: %02x offset: %03x\n", bar_val, offset);
+	if (bar_val & ~PCI_BASE_ADDRESS_MEM_MASK) {
+		dbgp_printk("only simple 32bit mmio bars supported\n");
+
+		return -1;
+	}
+
+	/* double check if the mem space is enabled */
+	byte = read_pci_config_byte(bus, slot, func, 0x04);
+	if (!(byte & 0x2)) {
+		byte  |= 0x02;
+		write_pci_config_byte(bus, slot, func, 0x04, byte);
+		dbgp_printk("mmio for ehci enabled\n");
+	}
+
+	/*
+	 * FIXME I don't have the bar size so just guess PAGE_SIZE is more
+	 * than enough.  1K is the biggest I have seen.
+	 */
+	set_fixmap_nocache(FIX_DBGP_BASE, bar_val & PAGE_MASK);
+	ehci_bar = (void __iomem *)__fix_to_virt(FIX_DBGP_BASE);
+	ehci_bar += bar_val & ~PAGE_MASK;
+	dbgp_printk("ehci_bar: %p\n", ehci_bar);
+
+	ehci_caps  = ehci_bar;
+	ehci_regs  = ehci_bar + HC_LENGTH(readl(&ehci_caps->hc_capbase));
+	ehci_debug = ehci_bar + offset;
+	ehci_dev.bus = bus;
+	ehci_dev.slot = slot;
+	ehci_dev.func = func;
+
+	detect_set_debug_port();
+
+	ret = ehci_setup();
+	if (ret < 0) {
+		dbgp_printk("ehci_setup failed\n");
+		ehci_debug = NULL;
+
+		return -1;
+	}
+
+	return 0;
+}
+
+static void early_dbgp_write(struct console *con, const char *str, u32 n)
+{
+	int chunk, ret;
+
+	if (!ehci_debug)
+		return;
+	while (n > 0) {
+		chunk = n;
+		if (chunk > DBGP_MAX_PACKET)
+			chunk = DBGP_MAX_PACKET;
+		ret = dbgp_bulk_write(USB_DEBUG_DEVNUM,
+			dbgp_endpoint_out, str, chunk);
+		str += chunk;
+		n -= chunk;
+	}
+}
+
+struct console early_dbgp_console = {
+	.name =		"earlydbg",
+	.write =	early_dbgp_write,
+	.flags =	CON_PRINTBUFFER,
+	.index =	-1,
+};
+