ehci-dbg.c

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/*
 * Copyright (c) 2001-2002 by David Brownell
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* this file is part of ehci-hcd.c */

#define ehci_dbg(ehci, fmt, args...) \
    dev_dbg (ehci_to_hcd(ehci)->self.controller , fmt , ## args )
#define ehci_err(ehci, fmt, args...) \
    dev_err (ehci_to_hcd(ehci)->self.controller , fmt , ## args )
#define ehci_info(ehci, fmt, args...) \
    dev_info (ehci_to_hcd(ehci)->self.controller , fmt , ## args )
#define ehci_warn(ehci, fmt, args...) \
    dev_warn (ehci_to_hcd(ehci)->self.controller , fmt , ## args )

#ifdef VERBOSE_DEBUG
#   define ehci_vdbg ehci_dbg
#else
    static inline void ehci_vdbg(struct ehci_hcd *ehci, ...) {}
#endif

#ifdef  DEBUG

/* check the values in the HCSPARAMS register
 * (host controller _Structural_ parameters)
 * see EHCI spec, Table 2-4 for each value
 */
static void dbg_hcs_params (struct ehci_hcd *ehci, char *label)
{
    u32 params = ehci_readl(ehci, &ehci->caps->hcs_params);

    ehci_dbg (ehci,
        "%s hcs_params 0x%x dbg=%d%s cc=%d pcc=%d%s%s ports=%d\n",
        label, params,
        HCS_DEBUG_PORT (params),
        HCS_INDICATOR (params) ? " ind" : "",
        HCS_N_CC (params),
        HCS_N_PCC (params),
        HCS_PORTROUTED (params) ? "" : " ordered",
        HCS_PPC (params) ? "" : " !ppc",
        HCS_N_PORTS (params)
        );
    /* Port routing, per EHCI 0.95 Spec, Section 2.2.5 */
    if (HCS_PORTROUTED (params)) {
        int i;
        char buf [46], tmp [7], byte;

        buf[0] = 0;
        for (i = 0; i < HCS_N_PORTS (params); i++) {
            // FIXME MIPS won't readb() ...
            byte = readb (&ehci->caps->portroute[(i>>1)]);
            sprintf(tmp, "%d ",
                ((i & 0x1) ? ((byte)&0xf) : ((byte>>4)&0xf)));
            strcat(buf, tmp);
        }
        ehci_dbg (ehci, "%s portroute %s\n",
                label, buf);
    }
}
#else

static inline void dbg_hcs_params (struct ehci_hcd *ehci, char *label) {}

#endif

#ifdef  DEBUG

/* check the values in the HCCPARAMS register
 * (host controller _Capability_ parameters)
 * see EHCI Spec, Table 2-5 for each value
 * */
static void dbg_hcc_params (struct ehci_hcd *ehci, char *label)
{
    u32 params = ehci_readl(ehci, &ehci->caps->hcc_params);

    if (HCC_ISOC_CACHE (params)) {
        ehci_dbg (ehci,
            "%s hcc_params %04x caching frame %s%s%s\n",
            label, params,
            HCC_PGM_FRAMELISTLEN(params) ? "256/512/1024" : "1024",
            HCC_CANPARK(params) ? " park" : "",
            HCC_64BIT_ADDR(params) ? " 64 bit addr" : "");
    } else {
        ehci_dbg (ehci,
            "%s hcc_params %04x thresh %d uframes %s%s%s%s%s%s%s\n",
            label,
            params,
            HCC_ISOC_THRES(params),
            HCC_PGM_FRAMELISTLEN(params) ? "256/512/1024" : "1024",
            HCC_CANPARK(params) ? " park" : "",
            HCC_64BIT_ADDR(params) ? " 64 bit addr" : "",
            HCC_LPM(params) ? " LPM" : "",
            HCC_PER_PORT_CHANGE_EVENT(params) ? " ppce" : "",
            HCC_HW_PREFETCH(params) ? " hw prefetch" : "",
            HCC_32FRAME_PERIODIC_LIST(params) ?
                " 32 periodic list" : "");
    }
}
#else

static inline void dbg_hcc_params (struct ehci_hcd *ehci, char *label) {}

#endif

#ifdef  DEBUG

static void __maybe_unused
dbg_qtd (const char *label, struct ehci_hcd *ehci, struct ehci_qtd *qtd)
{
    ehci_dbg(ehci, "%s td %p n%08x %08x t%08x p0=%08x\n", label, qtd,
        hc32_to_cpup(ehci, &qtd->hw_next),
        hc32_to_cpup(ehci, &qtd->hw_alt_next),
        hc32_to_cpup(ehci, &qtd->hw_token),
        hc32_to_cpup(ehci, &qtd->hw_buf [0]));
    if (qtd->hw_buf [1])
        ehci_dbg(ehci, "  p1=%08x p2=%08x p3=%08x p4=%08x\n",
            hc32_to_cpup(ehci, &qtd->hw_buf[1]),
            hc32_to_cpup(ehci, &qtd->hw_buf[2]),
            hc32_to_cpup(ehci, &qtd->hw_buf[3]),
            hc32_to_cpup(ehci, &qtd->hw_buf[4]));
}

static void __maybe_unused
dbg_qh (const char *label, struct ehci_hcd *ehci, struct ehci_qh *qh)
{
    struct ehci_qh_hw *hw = qh->hw;

    ehci_dbg (ehci, "%s qh %p n%08x info %x %x qtd %x\n", label,
        qh, hw->hw_next, hw->hw_info1, hw->hw_info2, hw->hw_current);
    dbg_qtd("overlay", ehci, (struct ehci_qtd *) &hw->hw_qtd_next);
}

static void __maybe_unused
dbg_itd (const char *label, struct ehci_hcd *ehci, struct ehci_itd *itd)
{
    ehci_dbg (ehci, "%s [%d] itd %p, next %08x, urb %p\n",
        label, itd->frame, itd, hc32_to_cpu(ehci, itd->hw_next),
        itd->urb);
    ehci_dbg (ehci,
        "  trans: %08x %08x %08x %08x %08x %08x %08x %08x\n",
        hc32_to_cpu(ehci, itd->hw_transaction[0]),
        hc32_to_cpu(ehci, itd->hw_transaction[1]),
        hc32_to_cpu(ehci, itd->hw_transaction[2]),
        hc32_to_cpu(ehci, itd->hw_transaction[3]),
        hc32_to_cpu(ehci, itd->hw_transaction[4]),
        hc32_to_cpu(ehci, itd->hw_transaction[5]),
        hc32_to_cpu(ehci, itd->hw_transaction[6]),
        hc32_to_cpu(ehci, itd->hw_transaction[7]));
    ehci_dbg (ehci,
        "  buf:   %08x %08x %08x %08x %08x %08x %08x\n",
        hc32_to_cpu(ehci, itd->hw_bufp[0]),
        hc32_to_cpu(ehci, itd->hw_bufp[1]),
        hc32_to_cpu(ehci, itd->hw_bufp[2]),
        hc32_to_cpu(ehci, itd->hw_bufp[3]),
        hc32_to_cpu(ehci, itd->hw_bufp[4]),
        hc32_to_cpu(ehci, itd->hw_bufp[5]),
        hc32_to_cpu(ehci, itd->hw_bufp[6]));
    ehci_dbg (ehci, "  index: %d %d %d %d %d %d %d %d\n",
        itd->index[0], itd->index[1], itd->index[2],
        itd->index[3], itd->index[4], itd->index[5],
        itd->index[6], itd->index[7]);
}

static void __maybe_unused
dbg_sitd (const char *label, struct ehci_hcd *ehci, struct ehci_sitd *sitd)
{
    ehci_dbg (ehci, "%s [%d] sitd %p, next %08x, urb %p\n",
        label, sitd->frame, sitd, hc32_to_cpu(ehci, sitd->hw_next),
        sitd->urb);
    ehci_dbg (ehci,
        "  addr %08x sched %04x result %08x buf %08x %08x\n",
        hc32_to_cpu(ehci, sitd->hw_fullspeed_ep),
        hc32_to_cpu(ehci, sitd->hw_uframe),
        hc32_to_cpu(ehci, sitd->hw_results),
        hc32_to_cpu(ehci, sitd->hw_buf[0]),
        hc32_to_cpu(ehci, sitd->hw_buf[1]));
}

static int __maybe_unused
dbg_status_buf (char *buf, unsigned len, const char *label, u32 status)
{
    return scnprintf (buf, len,
        "%s%sstatus %04x%s%s%s%s%s%s%s%s%s%s%s",
        label, label [0] ? " " : "", status,
        (status & STS_PPCE_MASK) ? " PPCE" : "",
        (status & STS_ASS) ? " Async" : "",
        (status & STS_PSS) ? " Periodic" : "",
        (status & STS_RECL) ? " Recl" : "",
        (status & STS_HALT) ? " Halt" : "",
        (status & STS_IAA) ? " IAA" : "",
        (status & STS_FATAL) ? " FATAL" : "",
        (status & STS_FLR) ? " FLR" : "",
        (status & STS_PCD) ? " PCD" : "",
        (status & STS_ERR) ? " ERR" : "",
        (status & STS_INT) ? " INT" : ""
        );
}

static int __maybe_unused
dbg_intr_buf (char *buf, unsigned len, const char *label, u32 enable)
{
    return scnprintf (buf, len,
        "%s%sintrenable %02x%s%s%s%s%s%s%s",
        label, label [0] ? " " : "", enable,
        (enable & STS_PPCE_MASK) ? " PPCE" : "",
        (enable & STS_IAA) ? " IAA" : "",
        (enable & STS_FATAL) ? " FATAL" : "",
        (enable & STS_FLR) ? " FLR" : "",
        (enable & STS_PCD) ? " PCD" : "",
        (enable & STS_ERR) ? " ERR" : "",
        (enable & STS_INT) ? " INT" : ""
        );
}

static const char *const fls_strings [] =
    { "1024", "512", "256", "??" };

static int
dbg_command_buf (char *buf, unsigned len, const char *label, u32 command)
{
    return scnprintf (buf, len,
        "%s%scommand %07x %s%s%s%s%s%s=%d ithresh=%d%s%s%s%s "
        "period=%s%s %s",
        label, label [0] ? " " : "", command,
        (command & CMD_HIRD) ? " HIRD" : "",
        (command & CMD_PPCEE) ? " PPCEE" : "",
        (command & CMD_FSP) ? " FSP" : "",
        (command & CMD_ASPE) ? " ASPE" : "",
        (command & CMD_PSPE) ? " PSPE" : "",
        (command & CMD_PARK) ? " park" : "(park)",
        CMD_PARK_CNT (command),
        (command >> 16) & 0x3f,
        (command & CMD_LRESET) ? " LReset" : "",
        (command & CMD_IAAD) ? " IAAD" : "",
        (command & CMD_ASE) ? " Async" : "",
        (command & CMD_PSE) ? " Periodic" : "",
        fls_strings [(command >> 2) & 0x3],
        (command & CMD_RESET) ? " Reset" : "",
        (command & CMD_RUN) ? "RUN" : "HALT"
        );
}

static int
dbg_port_buf (char *buf, unsigned len, const char *label, int port, u32 status)
{
    char    *sig;

    /* signaling state */
    switch (status & (3 << 10)) {
    case 0 << 10: sig = "se0"; break;
    case 1 << 10: sig = "k"; break;     /* low speed */
    case 2 << 10: sig = "j"; break;
    default: sig = "?"; break;
    }

    return scnprintf (buf, len,
        "%s%sport:%d status %06x %d %s%s%s%s%s%s "
        "sig=%s%s%s%s%s%s%s%s%s%s%s",
        label, label [0] ? " " : "", port, status,
        status>>25,/*device address */
        (status & PORT_SSTS)>>23 == PORTSC_SUSPEND_STS_ACK ?
                        " ACK" : "",
        (status & PORT_SSTS)>>23 == PORTSC_SUSPEND_STS_NYET ?
                        " NYET" : "",
        (status & PORT_SSTS)>>23 == PORTSC_SUSPEND_STS_STALL ?
                        " STALL" : "",
        (status & PORT_SSTS)>>23 == PORTSC_SUSPEND_STS_ERR ?
                        " ERR" : "",
        (status & PORT_POWER) ? " POWER" : "",
        (status & PORT_OWNER) ? " OWNER" : "",
        sig,
        (status & PORT_LPM) ? " LPM" : "",
        (status & PORT_RESET) ? " RESET" : "",
        (status & PORT_SUSPEND) ? " SUSPEND" : "",
        (status & PORT_RESUME) ? " RESUME" : "",
        (status & PORT_OCC) ? " OCC" : "",
        (status & PORT_OC) ? " OC" : "",
        (status & PORT_PEC) ? " PEC" : "",
        (status & PORT_PE) ? " PE" : "",
        (status & PORT_CSC) ? " CSC" : "",
        (status & PORT_CONNECT) ? " CONNECT" : "");
}

#else
static inline void __maybe_unused
dbg_qh (char *label, struct ehci_hcd *ehci, struct ehci_qh *qh)
{}

static inline int __maybe_unused
dbg_status_buf (char *buf, unsigned len, const char *label, u32 status)
{ return 0; }

static inline int __maybe_unused
dbg_command_buf (char *buf, unsigned len, const char *label, u32 command)
{ return 0; }

static inline int __maybe_unused
dbg_intr_buf (char *buf, unsigned len, const char *label, u32 enable)
{ return 0; }

static inline int __maybe_unused
dbg_port_buf (char *buf, unsigned len, const char *label, int port, u32 status)
{ return 0; }

#endif  /* DEBUG */

/* functions have the "wrong" filename when they're output... */
#define dbg_status(ehci, label, status) { \
    char _buf [80]; \
    dbg_status_buf (_buf, sizeof _buf, label, status); \
    ehci_dbg (ehci, "%s\n", _buf); \
}

#define dbg_cmd(ehci, label, command) { \
    char _buf [80]; \
    dbg_command_buf (_buf, sizeof _buf, label, command); \
    ehci_dbg (ehci, "%s\n", _buf); \
}

#define dbg_port(ehci, label, port, status) { \
    char _buf [80]; \
    dbg_port_buf (_buf, sizeof _buf, label, port, status); \
    ehci_dbg (ehci, "%s\n", _buf); \
}

/*-------------------------------------------------------------------------*/

#ifdef STUB_DEBUG_FILES

static inline void create_debug_files (struct ehci_hcd *bus) { }
static inline void remove_debug_files (struct ehci_hcd *bus) { }

#else

/* troubleshooting help: expose state in debugfs */

static int debug_async_open(struct inode *, struct file *);
static int debug_periodic_open(struct inode *, struct file *);
static int debug_registers_open(struct inode *, struct file *);
static int debug_async_open(struct inode *, struct file *);
static ssize_t debug_lpm_read(struct file *file, char __user *user_buf,
                   size_t count, loff_t *ppos);
static ssize_t debug_lpm_write(struct file *file, const char __user *buffer,
                  size_t count, loff_t *ppos);
static int debug_lpm_close(struct inode *inode, struct file *file);

static ssize_t debug_output(struct file*, char __user*, size_t, loff_t*);
static int debug_close(struct inode *, struct file *);

static const struct file_operations debug_async_fops = {
    .owner      = THIS_MODULE,
    .open       = debug_async_open,
    .read       = debug_output,
    .release    = debug_close,
    .llseek     = default_llseek,
};
static const struct file_operations debug_periodic_fops = {
    .owner      = THIS_MODULE,
    .open       = debug_periodic_open,
    .read       = debug_output,
    .release    = debug_close,
    .llseek     = default_llseek,
};
static const struct file_operations debug_registers_fops = {
    .owner      = THIS_MODULE,
    .open       = debug_registers_open,
    .read       = debug_output,
    .release    = debug_close,
    .llseek     = default_llseek,
};
static const struct file_operations debug_lpm_fops = {
    .owner      = THIS_MODULE,
    .open       = simple_open,
    .read       = debug_lpm_read,
    .write      = debug_lpm_write,
    .release    = debug_lpm_close,
    .llseek     = noop_llseek,
};

static struct dentry *ehci_debug_root;

struct debug_buffer {
    ssize_t (*fill_func)(struct debug_buffer *);    /* fill method */
    struct usb_bus *bus;
    struct mutex mutex; /* protect filling of buffer */
    size_t count;       /* number of characters filled into buffer */
    char *output_buf;
    size_t alloc_size;
};

#define speed_char(info1) ({ char tmp; \
        switch (info1 & (3 << 12)) { \
        case QH_FULL_SPEED: tmp = 'f'; break; \
        case QH_LOW_SPEED:  tmp = 'l'; break; \
        case QH_HIGH_SPEED: tmp = 'h'; break; \
        default: tmp = '?'; break; \
        }; tmp; })

static inline char token_mark(struct ehci_hcd *ehci, __hc32 token)
{
    __u32 v = hc32_to_cpu(ehci, token);

    if (v & QTD_STS_ACTIVE)
        return '*';
    if (v & QTD_STS_HALT)
        return '-';
    if (!IS_SHORT_READ (v))
        return ' ';
    /* tries to advance through hw_alt_next */
    return '/';
}

static void qh_lines (
    struct ehci_hcd *ehci,
    struct ehci_qh *qh,
    char **nextp,
    unsigned *sizep
)
{
    u32         scratch;
    u32         hw_curr;
    struct list_head    *entry;
    struct ehci_qtd     *td;
    unsigned        temp;
    unsigned        size = *sizep;
    char            *next = *nextp;
    char            mark;
    __le32          list_end = EHCI_LIST_END(ehci);
    struct ehci_qh_hw   *hw = qh->hw;

    if (hw->hw_qtd_next == list_end)    /* NEC does this */
        mark = '@';
    else
        mark = token_mark(ehci, hw->hw_token);
    if (mark == '/') {  /* qh_alt_next controls qh advance? */
        if ((hw->hw_alt_next & QTD_MASK(ehci))
                == ehci->async->hw->hw_alt_next)
            mark = '#'; /* blocked */
        else if (hw->hw_alt_next == list_end)
            mark = '.'; /* use hw_qtd_next */
        /* else alt_next points to some other qtd */
    }
    scratch = hc32_to_cpup(ehci, &hw->hw_info1);
    hw_curr = (mark == '*') ? hc32_to_cpup(ehci, &hw->hw_current) : 0;
    temp = scnprintf (next, size,
            "qh/%p dev%d %cs ep%d %08x %08x (%08x%c %s nak%d)",
            qh, scratch & 0x007f,
            speed_char (scratch),
            (scratch >> 8) & 0x000f,
            scratch, hc32_to_cpup(ehci, &hw->hw_info2),
            hc32_to_cpup(ehci, &hw->hw_token), mark,
            (cpu_to_hc32(ehci, QTD_TOGGLE) & hw->hw_token)
                ? "data1" : "data0",
            (hc32_to_cpup(ehci, &hw->hw_alt_next) >> 1) & 0x0f);
    size -= temp;
    next += temp;

    /* hc may be modifying the list as we read it ... */
    list_for_each (entry, &qh->qtd_list) {
        td = list_entry (entry, struct ehci_qtd, qtd_list);
        scratch = hc32_to_cpup(ehci, &td->hw_token);
        mark = ' ';
        if (hw_curr == td->qtd_dma)
            mark = '*';
        else if (hw->hw_qtd_next == cpu_to_hc32(ehci, td->qtd_dma))
            mark = '+';
        else if (QTD_LENGTH (scratch)) {
            if (td->hw_alt_next == ehci->async->hw->hw_alt_next)
                mark = '#';
            else if (td->hw_alt_next != list_end)
                mark = '/';
        }
        temp = snprintf (next, size,
                "\n\t%p%c%s len=%d %08x urb %p",
                td, mark, ({ char *tmp;
                 switch ((scratch>>8)&0x03) {
                 case 0: tmp = "out"; break;
                 case 1: tmp = "in"; break;
                 case 2: tmp = "setup"; break;
                 default: tmp = "?"; break;
                 } tmp;}),
                (scratch >> 16) & 0x7fff,
                scratch,
                td->urb);
        if (size < temp)
            temp = size;
        size -= temp;
        next += temp;
        if (temp == size)
            goto done;
    }

    temp = snprintf (next, size, "\n");
    if (size < temp)
        temp = size;
    size -= temp;
    next += temp;

done:
    *sizep = size;
    *nextp = next;
}

static ssize_t fill_async_buffer(struct debug_buffer *buf)
{
    struct usb_hcd      *hcd;
    struct ehci_hcd     *ehci;
    unsigned long       flags;
    unsigned        temp, size;
    char            *next;
    struct ehci_qh      *qh;

    hcd = bus_to_hcd(buf->bus);
    ehci = hcd_to_ehci (hcd);
    next = buf->output_buf;
    size = buf->alloc_size;

    *next = 0;

    /* dumps a snapshot of the async schedule.
     * usually empty except for long-term bulk reads, or head.
     * one QH per line, and TDs we know about
     */
    spin_lock_irqsave (&ehci->lock, flags);
    for (qh = ehci->async->qh_next.qh; size > 0 && qh; qh = qh->qh_next.qh)
        qh_lines (ehci, qh, &next, &size);
    if (ehci->async_unlink && size > 0) {
        temp = scnprintf(next, size, "\nunlink =\n");
        size -= temp;
        next += temp;

        for (qh = ehci->async_unlink; size > 0 && qh;
                qh = qh->unlink_next)
            qh_lines (ehci, qh, &next, &size);
    }
    spin_unlock_irqrestore (&ehci->lock, flags);

    return strlen(buf->output_buf);
}

#define DBG_SCHED_LIMIT 64
static ssize_t fill_periodic_buffer(struct debug_buffer *buf)
{
    struct usb_hcd      *hcd;
    struct ehci_hcd     *ehci;
    unsigned long       flags;
    union ehci_shadow   p, *seen;
    unsigned        temp, size, seen_count;
    char            *next;
    unsigned        i;
    __hc32          tag;

    if (!(seen = kmalloc (DBG_SCHED_LIMIT * sizeof *seen, GFP_ATOMIC)))
        return 0;
    seen_count = 0;

    hcd = bus_to_hcd(buf->bus);
    ehci = hcd_to_ehci (hcd);
    next = buf->output_buf;
    size = buf->alloc_size;

    temp = scnprintf (next, size, "size = %d\n", ehci->periodic_size);
    size -= temp;
    next += temp;

    /* dump a snapshot of the periodic schedule.
     * iso changes, interrupt usually doesn't.
     */
    spin_lock_irqsave (&ehci->lock, flags);
    for (i = 0; i < ehci->periodic_size; i++) {
        p = ehci->pshadow [i];
        if (likely (!p.ptr))
            continue;
        tag = Q_NEXT_TYPE(ehci, ehci->periodic [i]);

        temp = scnprintf (next, size, "%4d: ", i);
        size -= temp;
        next += temp;

        do {
            struct ehci_qh_hw *hw;

            switch (hc32_to_cpu(ehci, tag)) {
            case Q_TYPE_QH:
                hw = p.qh->hw;
                temp = scnprintf (next, size, " qh%d-%04x/%p",
                        p.qh->period,
                        hc32_to_cpup(ehci,
                            &hw->hw_info2)
                            /* uframe masks */
                            & (QH_CMASK | QH_SMASK),
                        p.qh);
                size -= temp;
                next += temp;
                /* don't repeat what follows this qh */
                for (temp = 0; temp < seen_count; temp++) {
                    if (seen [temp].ptr != p.ptr)
                        continue;
                    if (p.qh->qh_next.ptr) {
                        temp = scnprintf (next, size,
                            " ...");
                        size -= temp;
                        next += temp;
                    }
                    break;
                }
                /* show more info the first time around */
                if (temp == seen_count) {
                    u32 scratch = hc32_to_cpup(ehci,
                            &hw->hw_info1);
                    struct ehci_qtd *qtd;
                    char        *type = "";

                    /* count tds, get ep direction */
                    temp = 0;
                    list_for_each_entry (qtd,
                            &p.qh->qtd_list,
                            qtd_list) {
                        temp++;
                        switch (0x03 & (hc32_to_cpu(
                            ehci,
                            qtd->hw_token) >> 8)) {
                        case 0: type = "out"; continue;
                        case 1: type = "in"; continue;
                        }
                    }

                    temp = scnprintf (next, size,
                        " (%c%d ep%d%s "
                        "[%d/%d] q%d p%d)",
                        speed_char (scratch),
                        scratch & 0x007f,
                        (scratch >> 8) & 0x000f, type,
                        p.qh->usecs, p.qh->c_usecs,
                        temp,
                        0x7ff & (scratch >> 16));

                    if (seen_count < DBG_SCHED_LIMIT)
                        seen [seen_count++].qh = p.qh;
                } else
                    temp = 0;
                tag = Q_NEXT_TYPE(ehci, hw->hw_next);
                p = p.qh->qh_next;
                break;
            case Q_TYPE_FSTN:
                temp = scnprintf (next, size,
                    " fstn-%8x/%p", p.fstn->hw_prev,
                    p.fstn);
                tag = Q_NEXT_TYPE(ehci, p.fstn->hw_next);
                p = p.fstn->fstn_next;
                break;
            case Q_TYPE_ITD:
                temp = scnprintf (next, size,
                    " itd/%p", p.itd);
                tag = Q_NEXT_TYPE(ehci, p.itd->hw_next);
                p = p.itd->itd_next;
                break;
            case Q_TYPE_SITD:
                temp = scnprintf (next, size,
                    " sitd%d-%04x/%p",
                    p.sitd->stream->interval,
                    hc32_to_cpup(ehci, &p.sitd->hw_uframe)
                        & 0x0000ffff,
                    p.sitd);
                tag = Q_NEXT_TYPE(ehci, p.sitd->hw_next);
                p = p.sitd->sitd_next;
                break;
            }
            size -= temp;
            next += temp;
        } while (p.ptr);

        temp = scnprintf (next, size, "\n");
        size -= temp;
        next += temp;
    }
    spin_unlock_irqrestore (&ehci->lock, flags);
    kfree (seen);

    return buf->alloc_size - size;
}
#undef DBG_SCHED_LIMIT

static const char *rh_state_string(struct ehci_hcd *ehci)
{
    switch (ehci->rh_state) {
    case EHCI_RH_HALTED:
        return "halted";
    case EHCI_RH_SUSPENDED:
        return "suspended";
    case EHCI_RH_RUNNING:
        return "running";
    case EHCI_RH_STOPPING:
        return "stopping";
    }
    return "?";
}

static ssize_t fill_registers_buffer(struct debug_buffer *buf)
{
    struct usb_hcd      *hcd;
    struct ehci_hcd     *ehci;
    unsigned long       flags;
    unsigned        temp, size, i;
    char            *next, scratch [80];
    static char     fmt [] = "%*s\n";
    static char     label [] = "";

    hcd = bus_to_hcd(buf->bus);
    ehci = hcd_to_ehci (hcd);
    next = buf->output_buf;
    size = buf->alloc_size;

    spin_lock_irqsave (&ehci->lock, flags);

    if (!HCD_HW_ACCESSIBLE(hcd)) {
        size = scnprintf (next, size,
            "bus %s, device %s\n"
            "%s\n"
            "SUSPENDED (no register access)\n",
            hcd->self.controller->bus->name,
            dev_name(hcd->self.controller),
            hcd->product_desc);
        goto done;
    }

    /* Capability Registers */
    i = HC_VERSION(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase));
    temp = scnprintf (next, size,
        "bus %s, device %s\n"
        "%s\n"
        "EHCI %x.%02x, rh state %s\n",
        hcd->self.controller->bus->name,
        dev_name(hcd->self.controller),
        hcd->product_desc,
        i >> 8, i & 0x0ff, rh_state_string(ehci));
    size -= temp;
    next += temp;

#ifdef  CONFIG_PCI
    /* EHCI 0.96 and later may have "extended capabilities" */
    if (hcd->self.controller->bus == &pci_bus_type) {
        struct pci_dev  *pdev;
        u32     offset, cap, cap2;
        unsigned    count = 256/4;

        pdev = to_pci_dev(ehci_to_hcd(ehci)->self.controller);
        offset = HCC_EXT_CAPS(ehci_readl(ehci,
                &ehci->caps->hcc_params));
        while (offset && count--) {
            pci_read_config_dword (pdev, offset, &cap);
            switch (cap & 0xff) {
            case 1:
                temp = scnprintf (next, size,
                    "ownership %08x%s%s\n", cap,
                    (cap & (1 << 24)) ? " linux" : "",
                    (cap & (1 << 16)) ? " firmware" : "");
                size -= temp;
                next += temp;

                offset += 4;
                pci_read_config_dword (pdev, offset, &cap2);
                temp = scnprintf (next, size,
                    "SMI sts/enable 0x%08x\n", cap2);
                size -= temp;
                next += temp;
                break;
            case 0:     /* illegal reserved capability */
                cap = 0;
                /* FALLTHROUGH */
            default:        /* unknown */
                break;
            }
            temp = (cap >> 8) & 0xff;
        }
    }
#endif

    // FIXME interpret both types of params
    i = ehci_readl(ehci, &ehci->caps->hcs_params);
    temp = scnprintf (next, size, "structural params 0x%08x\n", i);
    size -= temp;
    next += temp;

    i = ehci_readl(ehci, &ehci->caps->hcc_params);
    temp = scnprintf (next, size, "capability params 0x%08x\n", i);
    size -= temp;
    next += temp;

    /* Operational Registers */
    temp = dbg_status_buf (scratch, sizeof scratch, label,
            ehci_readl(ehci, &ehci->regs->status));
    temp = scnprintf (next, size, fmt, temp, scratch);
    size -= temp;
    next += temp;

    temp = dbg_command_buf (scratch, sizeof scratch, label,
            ehci_readl(ehci, &ehci->regs->command));
    temp = scnprintf (next, size, fmt, temp, scratch);
    size -= temp;
    next += temp;

    temp = dbg_intr_buf (scratch, sizeof scratch, label,
            ehci_readl(ehci, &ehci->regs->intr_enable));
    temp = scnprintf (next, size, fmt, temp, scratch);
    size -= temp;
    next += temp;

    temp = scnprintf (next, size, "uframe %04x\n",
            ehci_read_frame_index(ehci));
    size -= temp;
    next += temp;

    for (i = 1; i <= HCS_N_PORTS (ehci->hcs_params); i++) {
        temp = dbg_port_buf (scratch, sizeof scratch, label, i,
                ehci_readl(ehci,
                    &ehci->regs->port_status[i - 1]));
        temp = scnprintf (next, size, fmt, temp, scratch);
        size -= temp;
        next += temp;
        if (i == HCS_DEBUG_PORT(ehci->hcs_params) && ehci->debug) {
            temp = scnprintf (next, size,
                    "    debug control %08x\n",
                    ehci_readl(ehci,
                        &ehci->debug->control));
            size -= temp;
            next += temp;
        }
    }

    if (ehci->async_unlink) {
        temp = scnprintf(next, size, "async unlink qh %p\n",
                ehci->async_unlink);
        size -= temp;
        next += temp;
    }

#ifdef EHCI_STATS
    temp = scnprintf (next, size,
        "irq normal %ld err %ld iaa %ld (lost %ld)\n",
        ehci->stats.normal, ehci->stats.error, ehci->stats.iaa,
        ehci->stats.lost_iaa);
    size -= temp;
    next += temp;

    temp = scnprintf (next, size, "complete %ld unlink %ld\n",
        ehci->stats.complete, ehci->stats.unlink);
    size -= temp;
    next += temp;
#endif

done:
    spin_unlock_irqrestore (&ehci->lock, flags);

    return buf->alloc_size - size;
}

static struct debug_buffer *alloc_buffer(struct usb_bus *bus,
                ssize_t (*fill_func)(struct debug_buffer *))
{
    struct debug_buffer *buf;

    buf = kzalloc(sizeof(struct debug_buffer), GFP_KERNEL);

    if (buf) {
        buf->bus = bus;
        buf->fill_func = fill_func;
        mutex_init(&buf->mutex);
        buf->alloc_size = PAGE_SIZE;
    }

    return buf;
}

static int fill_buffer(struct debug_buffer *buf)
{
    int ret = 0;

    if (!buf->output_buf)
        buf->output_buf = vmalloc(buf->alloc_size);

    if (!buf->output_buf) {
        ret = -ENOMEM;
        goto out;
    }

    ret = buf->fill_func(buf);

    if (ret >= 0) {
        buf->count = ret;
        ret = 0;
    }

out:
    return ret;
}

static ssize_t debug_output(struct file *file, char __user *user_buf,
                size_t len, loff_t *offset)
{
    struct debug_buffer *buf = file->private_data;
    int ret = 0;

    mutex_lock(&buf->mutex);
    if (buf->count == 0) {
        ret = fill_buffer(buf);
        if (ret != 0) {
            mutex_unlock(&buf->mutex);
            goto out;
        }
    }
    mutex_unlock(&buf->mutex);

    ret = simple_read_from_buffer(user_buf, len, offset,
                      buf->output_buf, buf->count);

out:
    return ret;

}

static int debug_close(struct inode *inode, struct file *file)
{
    struct debug_buffer *buf = file->private_data;

    if (buf) {
        vfree(buf->output_buf);
        kfree(buf);
    }

    return 0;
}
static int debug_async_open(struct inode *inode, struct file *file)
{
    file->private_data = alloc_buffer(inode->i_private, fill_async_buffer);

    return file->private_data ? 0 : -ENOMEM;
}

static int debug_periodic_open(struct inode *inode, struct file *file)
{
    struct debug_buffer *buf;
    buf = alloc_buffer(inode->i_private, fill_periodic_buffer);
    if (!buf)
        return -ENOMEM;

    buf->alloc_size = (sizeof(void *) == 4 ? 6 : 8)*PAGE_SIZE;
    file->private_data = buf;
    return 0;
}

static int debug_registers_open(struct inode *inode, struct file *file)
{
    file->private_data = alloc_buffer(inode->i_private,
                      fill_registers_buffer);

    return file->private_data ? 0 : -ENOMEM;
}

static int debug_lpm_close(struct inode *inode, struct file *file)
{
    return 0;
}

static ssize_t debug_lpm_read(struct file *file, char __user *user_buf,
                   size_t count, loff_t *ppos)
{
    /* TODO: show lpm stats */
    return 0;
}

static ssize_t debug_lpm_write(struct file *file, const char __user *user_buf,
                  size_t count, loff_t *ppos)
{
    struct usb_hcd      *hcd;
    struct ehci_hcd     *ehci;
    char buf[50];
    size_t len;
    u32 temp;
    unsigned long port;
    u32 __iomem *portsc ;
    u32 params;

    hcd = bus_to_hcd(file->private_data);
    ehci = hcd_to_ehci(hcd);

    len = min(count, sizeof(buf) - 1);
    if (copy_from_user(buf, user_buf, len))
        return -EFAULT;
    buf[len] = '\0';
    if (len > 0 && buf[len - 1] == '\n')
        buf[len - 1] = '\0';

    if (strncmp(buf, "enable", 5) == 0) {
        if (strict_strtoul(buf + 7, 10, &port))
            return -EINVAL;
        params = ehci_readl(ehci, &ehci->caps->hcs_params);
        if (port > HCS_N_PORTS(params)) {
            ehci_dbg(ehci, "ERR: LPM on bad port %lu\n", port);
            return -ENODEV;
        }
        portsc = &ehci->regs->port_status[port-1];
        temp = ehci_readl(ehci, portsc);
        if (!(temp & PORT_DEV_ADDR)) {
            ehci_dbg(ehci, "LPM: no device attached\n");
            return -ENODEV;
        }
        temp |= PORT_LPM;
        ehci_writel(ehci, temp, portsc);
        printk(KERN_INFO "force enable LPM for port %lu\n", port);
    } else if (strncmp(buf, "hird=", 5) == 0) {
        unsigned long hird;
        if (strict_strtoul(buf + 5, 16, &hird))
            return -EINVAL;
        printk(KERN_INFO "setting hird %s %lu\n", buf + 6, hird);
        ehci->command = (ehci->command & ~CMD_HIRD) | (hird << 24);
        ehci_writel(ehci, ehci->command, &ehci->regs->command);
    } else if (strncmp(buf, "disable", 7) == 0) {
        if (strict_strtoul(buf + 8, 10, &port))
            return -EINVAL;
        params = ehci_readl(ehci, &ehci->caps->hcs_params);
        if (port > HCS_N_PORTS(params)) {
            ehci_dbg(ehci, "ERR: LPM off bad port %lu\n", port);
            return -ENODEV;
        }
        portsc = &ehci->regs->port_status[port-1];
        temp = ehci_readl(ehci, portsc);
        if (!(temp & PORT_DEV_ADDR)) {
            ehci_dbg(ehci, "ERR: no device attached\n");
            return -ENODEV;
        }
        temp &= ~PORT_LPM;
        ehci_writel(ehci, temp, portsc);
        printk(KERN_INFO "disabled LPM for port %lu\n", port);
    } else
        return -EOPNOTSUPP;
    return count;
}

static inline void create_debug_files (struct ehci_hcd *ehci)
{
    struct usb_bus *bus = &ehci_to_hcd(ehci)->self;

    ehci->debug_dir = debugfs_create_dir(bus->bus_name, ehci_debug_root);
    if (!ehci->debug_dir)
        return;

    if (!debugfs_create_file("async", S_IRUGO, ehci->debug_dir, bus,
                        &debug_async_fops))
        goto file_error;

    if (!debugfs_create_file("periodic", S_IRUGO, ehci->debug_dir, bus,
                        &debug_periodic_fops))
        goto file_error;

    if (!debugfs_create_file("registers", S_IRUGO, ehci->debug_dir, bus,
                            &debug_registers_fops))
        goto file_error;

    if (!debugfs_create_file("lpm", S_IRUGO|S_IWUSR, ehci->debug_dir, bus,
                            &debug_lpm_fops))
        goto file_error;

    return;

file_error:
    debugfs_remove_recursive(ehci->debug_dir);
}

static inline void remove_debug_files (struct ehci_hcd *ehci)
{
    debugfs_remove_recursive(ehci->debug_dir);
}

#endif /* STUB_DEBUG_FILES */