#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,
};