ohci-dbg.c

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/*
 * OHCI HCD (Host Controller Driver) for USB.
 *
 * (C) Copyright 1999 Roman Weissgaerber <[email protected]>
 * (C) Copyright 2000-2002 David Brownell <[email protected]>
 *
 * This file is licenced under the GPL.
 */

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

#ifdef DEBUG

#define edstring(ed_type) ({ char *temp; \
    switch (ed_type) { \
    case PIPE_CONTROL:  temp = "ctrl"; break; \
    case PIPE_BULK:     temp = "bulk"; break; \
    case PIPE_INTERRUPT:    temp = "intr"; break; \
    default:        temp = "isoc"; break; \
    }; temp;})
#define pipestring(pipe) edstring(usb_pipetype(pipe))

/* debug| print the main components of an URB
 * small: 0) header + data packets 1) just header
 */
static void __maybe_unused
urb_print(struct urb * urb, char * str, int small, int status)
{
    unsigned int pipe= urb->pipe;

    if (!urb->dev || !urb->dev->bus) {
        printk(KERN_DEBUG "%s URB: no dev\n", str);
        return;
    }

#ifndef OHCI_VERBOSE_DEBUG
    if (status != 0)
#endif
    printk(KERN_DEBUG "%s %p dev=%d ep=%d%s-%s flags=%x len=%d/%d stat=%d\n",
            str,
            urb,
            usb_pipedevice (pipe),
            usb_pipeendpoint (pipe),
            usb_pipeout (pipe)? "out" : "in",
            pipestring (pipe),
            urb->transfer_flags,
            urb->actual_length,
            urb->transfer_buffer_length,
            status);

#ifdef  OHCI_VERBOSE_DEBUG
    if (!small) {
        int i, len;

        if (usb_pipecontrol (pipe)) {
            printk (KERN_DEBUG "%s: setup(8):", __FILE__);
            for (i = 0; i < 8 ; i++)
                printk (" %02x", ((__u8 *) urb->setup_packet) [i]);
            printk ("\n");
        }
        if (urb->transfer_buffer_length > 0 && urb->transfer_buffer) {
            printk (KERN_DEBUG "%s: data(%d/%d):", __FILE__,
                urb->actual_length,
                urb->transfer_buffer_length);
            len = usb_pipeout (pipe)?
                        urb->transfer_buffer_length: urb->actual_length;
            for (i = 0; i < 16 && i < len; i++)
                printk (" %02x", ((__u8 *) urb->transfer_buffer) [i]);
            printk ("%s stat:%d\n", i < len? "...": "", status);
        }
    }
#endif
}

#define ohci_dbg_sw(ohci, next, size, format, arg...) \
    do { \
    if (next != NULL) { \
        unsigned s_len; \
        s_len = scnprintf (*next, *size, format, ## arg ); \
        *size -= s_len; *next += s_len; \
    } else \
        ohci_dbg(ohci,format, ## arg ); \
    } while (0);

/* Version for use where "next" is the address of a local variable */
#define ohci_dbg_nosw(ohci, next, size, format, arg...) \
    do { \
        unsigned s_len; \
        s_len = scnprintf(*next, *size, format, ## arg); \
        *size -= s_len; *next += s_len; \
    } while (0);


static void ohci_dump_intr_mask (
    struct ohci_hcd *ohci,
    char *label,
    u32 mask,
    char **next,
    unsigned *size)
{
    ohci_dbg_sw (ohci, next, size, "%s 0x%08x%s%s%s%s%s%s%s%s%s\n",
        label,
        mask,
        (mask & OHCI_INTR_MIE) ? " MIE" : "",
        (mask & OHCI_INTR_OC) ? " OC" : "",
        (mask & OHCI_INTR_RHSC) ? " RHSC" : "",
        (mask & OHCI_INTR_FNO) ? " FNO" : "",
        (mask & OHCI_INTR_UE) ? " UE" : "",
        (mask & OHCI_INTR_RD) ? " RD" : "",
        (mask & OHCI_INTR_SF) ? " SF" : "",
        (mask & OHCI_INTR_WDH) ? " WDH" : "",
        (mask & OHCI_INTR_SO) ? " SO" : ""
        );
}

static void maybe_print_eds (
    struct ohci_hcd *ohci,
    char *label,
    u32 value,
    char **next,
    unsigned *size)
{
    if (value)
        ohci_dbg_sw (ohci, next, size, "%s %08x\n", label, value);
}

static char *hcfs2string (int state)
{
    switch (state) {
        case OHCI_USB_RESET:    return "reset";
        case OHCI_USB_RESUME:   return "resume";
        case OHCI_USB_OPER: return "operational";
        case OHCI_USB_SUSPEND:  return "suspend";
    }
    return "?";
}

static const char *rh_state_string(struct ohci_hcd *ohci)
{
    switch (ohci->rh_state) {
    case OHCI_RH_HALTED:
        return "halted";
    case OHCI_RH_SUSPENDED:
        return "suspended";
    case OHCI_RH_RUNNING:
        return "running";
    }
    return "?";
}

// dump control and status registers
static void
ohci_dump_status (struct ohci_hcd *controller, char **next, unsigned *size)
{
    struct ohci_regs __iomem *regs = controller->regs;
    u32         temp;

    temp = ohci_readl (controller, &regs->revision) & 0xff;
    ohci_dbg_sw (controller, next, size,
        "OHCI %d.%d, %s legacy support registers, rh state %s\n",
        0x03 & (temp >> 4), (temp & 0x0f),
        (temp & 0x0100) ? "with" : "NO",
        rh_state_string(controller));

    temp = ohci_readl (controller, &regs->control);
    ohci_dbg_sw (controller, next, size,
        "control 0x%03x%s%s%s HCFS=%s%s%s%s%s CBSR=%d\n",
        temp,
        (temp & OHCI_CTRL_RWE) ? " RWE" : "",
        (temp & OHCI_CTRL_RWC) ? " RWC" : "",
        (temp & OHCI_CTRL_IR) ? " IR" : "",
        hcfs2string (temp & OHCI_CTRL_HCFS),
        (temp & OHCI_CTRL_BLE) ? " BLE" : "",
        (temp & OHCI_CTRL_CLE) ? " CLE" : "",
        (temp & OHCI_CTRL_IE) ? " IE" : "",
        (temp & OHCI_CTRL_PLE) ? " PLE" : "",
        temp & OHCI_CTRL_CBSR
        );

    temp = ohci_readl (controller, &regs->cmdstatus);
    ohci_dbg_sw (controller, next, size,
        "cmdstatus 0x%05x SOC=%d%s%s%s%s\n", temp,
        (temp & OHCI_SOC) >> 16,
        (temp & OHCI_OCR) ? " OCR" : "",
        (temp & OHCI_BLF) ? " BLF" : "",
        (temp & OHCI_CLF) ? " CLF" : "",
        (temp & OHCI_HCR) ? " HCR" : ""
        );

    ohci_dump_intr_mask (controller, "intrstatus",
            ohci_readl (controller, &regs->intrstatus),
            next, size);
    ohci_dump_intr_mask (controller, "intrenable",
            ohci_readl (controller, &regs->intrenable),
            next, size);
    // intrdisable always same as intrenable

    maybe_print_eds (controller, "ed_periodcurrent",
            ohci_readl (controller, &regs->ed_periodcurrent),
            next, size);

    maybe_print_eds (controller, "ed_controlhead",
            ohci_readl (controller, &regs->ed_controlhead),
            next, size);
    maybe_print_eds (controller, "ed_controlcurrent",
            ohci_readl (controller, &regs->ed_controlcurrent),
            next, size);

    maybe_print_eds (controller, "ed_bulkhead",
            ohci_readl (controller, &regs->ed_bulkhead),
            next, size);
    maybe_print_eds (controller, "ed_bulkcurrent",
            ohci_readl (controller, &regs->ed_bulkcurrent),
            next, size);

    maybe_print_eds (controller, "donehead",
            ohci_readl (controller, &regs->donehead), next, size);
}

#define dbg_port_sw(hc,num,value,next,size) \
    ohci_dbg_sw (hc, next, size, \
        "roothub.portstatus [%d] " \
        "0x%08x%s%s%s%s%s%s%s%s%s%s%s%s\n", \
        num, temp, \
        (temp & RH_PS_PRSC) ? " PRSC" : "", \
        (temp & RH_PS_OCIC) ? " OCIC" : "", \
        (temp & RH_PS_PSSC) ? " PSSC" : "", \
        (temp & RH_PS_PESC) ? " PESC" : "", \
        (temp & RH_PS_CSC) ? " CSC" : "", \
        \
        (temp & RH_PS_LSDA) ? " LSDA" : "", \
        (temp & RH_PS_PPS) ? " PPS" : "", \
        (temp & RH_PS_PRS) ? " PRS" : "", \
        (temp & RH_PS_POCI) ? " POCI" : "", \
        (temp & RH_PS_PSS) ? " PSS" : "", \
        \
        (temp & RH_PS_PES) ? " PES" : "", \
        (temp & RH_PS_CCS) ? " CCS" : "" \
        );


static void
ohci_dump_roothub (
    struct ohci_hcd *controller,
    int verbose,
    char **next,
    unsigned *size)
{
    u32         temp, i;

    temp = roothub_a (controller);
    if (temp == ~(u32)0)
        return;

    if (verbose) {
        ohci_dbg_sw (controller, next, size,
            "roothub.a %08x POTPGT=%d%s%s%s%s%s NDP=%d(%d)\n", temp,
            ((temp & RH_A_POTPGT) >> 24) & 0xff,
            (temp & RH_A_NOCP) ? " NOCP" : "",
            (temp & RH_A_OCPM) ? " OCPM" : "",
            (temp & RH_A_DT) ? " DT" : "",
            (temp & RH_A_NPS) ? " NPS" : "",
            (temp & RH_A_PSM) ? " PSM" : "",
            (temp & RH_A_NDP), controller->num_ports
            );
        temp = roothub_b (controller);
        ohci_dbg_sw (controller, next, size,
            "roothub.b %08x PPCM=%04x DR=%04x\n",
            temp,
            (temp & RH_B_PPCM) >> 16,
            (temp & RH_B_DR)
            );
        temp = roothub_status (controller);
        ohci_dbg_sw (controller, next, size,
            "roothub.status %08x%s%s%s%s%s%s\n",
            temp,
            (temp & RH_HS_CRWE) ? " CRWE" : "",
            (temp & RH_HS_OCIC) ? " OCIC" : "",
            (temp & RH_HS_LPSC) ? " LPSC" : "",
            (temp & RH_HS_DRWE) ? " DRWE" : "",
            (temp & RH_HS_OCI) ? " OCI" : "",
            (temp & RH_HS_LPS) ? " LPS" : ""
            );
    }

    for (i = 0; i < controller->num_ports; i++) {
        temp = roothub_portstatus (controller, i);
        dbg_port_sw (controller, i, temp, next, size);
    }
}

static void ohci_dump (struct ohci_hcd *controller, int verbose)
{
    ohci_dbg (controller, "OHCI controller state\n");

    // dumps some of the state we know about
    ohci_dump_status (controller, NULL, NULL);
    if (controller->hcca)
        ohci_dbg (controller,
            "hcca frame #%04x\n", ohci_frame_no(controller));
    ohci_dump_roothub (controller, 1, NULL, NULL);
}

static const char data0 [] = "DATA0";
static const char data1 [] = "DATA1";

static void ohci_dump_td (const struct ohci_hcd *ohci, const char *label,
        const struct td *td)
{
    u32 tmp = hc32_to_cpup (ohci, &td->hwINFO);

    ohci_dbg (ohci, "%s td %p%s; urb %p index %d; hw next td %08x\n",
        label, td,
        (tmp & TD_DONE) ? " (DONE)" : "",
        td->urb, td->index,
        hc32_to_cpup (ohci, &td->hwNextTD));
    if ((tmp & TD_ISO) == 0) {
        const char  *toggle, *pid;
        u32 cbp, be;

        switch (tmp & TD_T) {
        case TD_T_DATA0: toggle = data0; break;
        case TD_T_DATA1: toggle = data1; break;
        case TD_T_TOGGLE: toggle = "(CARRY)"; break;
        default: toggle = "(?)"; break;
        }
        switch (tmp & TD_DP) {
        case TD_DP_SETUP: pid = "SETUP"; break;
        case TD_DP_IN: pid = "IN"; break;
        case TD_DP_OUT: pid = "OUT"; break;
        default: pid = "(bad pid)"; break;
        }
        ohci_dbg (ohci, "     info %08x CC=%x %s DI=%d %s %s\n", tmp,
            TD_CC_GET(tmp), /* EC, */ toggle,
            (tmp & TD_DI) >> 21, pid,
            (tmp & TD_R) ? "R" : "");
        cbp = hc32_to_cpup (ohci, &td->hwCBP);
        be = hc32_to_cpup (ohci, &td->hwBE);
        ohci_dbg (ohci, "     cbp %08x be %08x (len %d)\n", cbp, be,
            cbp ? (be + 1 - cbp) : 0);
    } else {
        unsigned    i;
        ohci_dbg (ohci, "  info %08x CC=%x FC=%d DI=%d SF=%04x\n", tmp,
            TD_CC_GET(tmp),
            (tmp >> 24) & 0x07,
            (tmp & TD_DI) >> 21,
            tmp & 0x0000ffff);
        ohci_dbg (ohci, "  bp0 %08x be %08x\n",
            hc32_to_cpup (ohci, &td->hwCBP) & ~0x0fff,
            hc32_to_cpup (ohci, &td->hwBE));
        for (i = 0; i < MAXPSW; i++) {
            u16 psw = ohci_hwPSW (ohci, td, i);
            int cc = (psw >> 12) & 0x0f;
            ohci_dbg (ohci, "    psw [%d] = %2x, CC=%x %s=%d\n", i,
                psw, cc,
                (cc >= 0x0e) ? "OFFSET" : "SIZE",
                psw & 0x0fff);
        }
    }
}

/* caller MUST own hcd spinlock if verbose is set! */
static void __maybe_unused
ohci_dump_ed (const struct ohci_hcd *ohci, const char *label,
        const struct ed *ed, int verbose)
{
    u32 tmp = hc32_to_cpu (ohci, ed->hwINFO);
    char    *type = "";

    ohci_dbg (ohci, "%s, ed %p state 0x%x type %s; next ed %08x\n",
        label,
        ed, ed->state, edstring (ed->type),
        hc32_to_cpup (ohci, &ed->hwNextED));
    switch (tmp & (ED_IN|ED_OUT)) {
    case ED_OUT: type = "-OUT"; break;
    case ED_IN: type = "-IN"; break;
    /* else from TDs ... control */
    }
    ohci_dbg (ohci,
        "  info %08x MAX=%d%s%s%s%s EP=%d%s DEV=%d\n", tmp,
        0x03ff & (tmp >> 16),
        (tmp & ED_DEQUEUE) ? " DQ" : "",
        (tmp & ED_ISO) ? " ISO" : "",
        (tmp & ED_SKIP) ? " SKIP" : "",
        (tmp & ED_LOWSPEED) ? " LOW" : "",
        0x000f & (tmp >> 7),
        type,
        0x007f & tmp);
    tmp = hc32_to_cpup (ohci, &ed->hwHeadP);
    ohci_dbg (ohci, "  tds: head %08x %s%s tail %08x%s\n",
        tmp,
        (tmp & ED_C) ? data1 : data0,
        (tmp & ED_H) ? " HALT" : "",
        hc32_to_cpup (ohci, &ed->hwTailP),
        verbose ? "" : " (not listing)");
    if (verbose) {
        struct list_head    *tmp;

        /* use ed->td_list because HC concurrently modifies
         * hwNextTD as it accumulates ed_donelist.
         */
        list_for_each (tmp, &ed->td_list) {
            struct td       *td;
            td = list_entry (tmp, struct td, td_list);
            ohci_dump_td (ohci, "  ->", td);
        }
    }
}

#else
static inline void ohci_dump (struct ohci_hcd *controller, int verbose) {}

#undef OHCI_VERBOSE_DEBUG

#endif /* DEBUG */

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

#ifdef STUB_DEBUG_FILES

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

#else

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_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 struct dentry *ohci_debug_root;

struct debug_buffer {
    ssize_t (*fill_func)(struct debug_buffer *);    /* fill method */
    struct ohci_hcd *ohci;
    struct mutex mutex; /* protect filling of buffer */
    size_t count;       /* number of characters filled into buffer */
    char *page;
};

static ssize_t
show_list (struct ohci_hcd *ohci, char *buf, size_t count, struct ed *ed)
{
    unsigned        temp, size = count;

    if (!ed)
        return 0;

    /* print first --> last */
    while (ed->ed_prev)
        ed = ed->ed_prev;

    /* dump a snapshot of the bulk or control schedule */
    while (ed) {
        u32     info = hc32_to_cpu (ohci, ed->hwINFO);
        u32     headp = hc32_to_cpu (ohci, ed->hwHeadP);
        struct list_head *entry;
        struct td   *td;

        temp = scnprintf (buf, size,
            "ed/%p %cs dev%d ep%d%s max %d %08x%s%s %s",
            ed,
            (info & ED_LOWSPEED) ? 'l' : 'f',
            info & 0x7f,
            (info >> 7) & 0xf,
            (info & ED_IN) ? "in" : "out",
            0x03ff & (info >> 16),
            info,
            (info & ED_SKIP) ? " s" : "",
            (headp & ED_H) ? " H" : "",
            (headp & ED_C) ? data1 : data0);
        size -= temp;
        buf += temp;

        list_for_each (entry, &ed->td_list) {
            u32     cbp, be;

            td = list_entry (entry, struct td, td_list);
            info = hc32_to_cpup (ohci, &td->hwINFO);
            cbp = hc32_to_cpup (ohci, &td->hwCBP);
            be = hc32_to_cpup (ohci, &td->hwBE);
            temp = scnprintf (buf, size,
                    "\n\ttd %p %s %d cc=%x urb %p (%08x)",
                    td,
                    ({ char *pid;
                    switch (info & TD_DP) {
                    case TD_DP_SETUP: pid = "setup"; break;
                    case TD_DP_IN: pid = "in"; break;
                    case TD_DP_OUT: pid = "out"; break;
                    default: pid = "(?)"; break;
                     } pid;}),
                    cbp ? (be + 1 - cbp) : 0,
                    TD_CC_GET (info), td->urb, info);
            size -= temp;
            buf += temp;
        }

        temp = scnprintf (buf, size, "\n");
        size -= temp;
        buf += temp;

        ed = ed->ed_next;
    }
    return count - size;
}

static ssize_t fill_async_buffer(struct debug_buffer *buf)
{
    struct ohci_hcd     *ohci;
    size_t          temp;
    unsigned long       flags;

    ohci = buf->ohci;

    /* display control and bulk lists together, for simplicity */
    spin_lock_irqsave (&ohci->lock, flags);
    temp = show_list(ohci, buf->page, buf->count, ohci->ed_controltail);
    temp += show_list(ohci, buf->page + temp, buf->count - temp,
              ohci->ed_bulktail);
    spin_unlock_irqrestore (&ohci->lock, flags);

    return temp;
}

#define DBG_SCHED_LIMIT 64

static ssize_t fill_periodic_buffer(struct debug_buffer *buf)
{
    struct ohci_hcd     *ohci;
    struct ed       **seen, *ed;
    unsigned long       flags;
    unsigned        temp, size, seen_count;
    char            *next;
    unsigned        i;

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

    ohci = buf->ohci;
    next = buf->page;
    size = PAGE_SIZE;

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

    /* dump a snapshot of the periodic schedule (and load) */
    spin_lock_irqsave (&ohci->lock, flags);
    for (i = 0; i < NUM_INTS; i++) {
        if (!(ed = ohci->periodic [i]))
            continue;

        temp = scnprintf (next, size, "%2d [%3d]:", i, ohci->load [i]);
        size -= temp;
        next += temp;

        do {
            temp = scnprintf (next, size, " ed%d/%p",
                ed->interval, ed);
            size -= temp;
            next += temp;
            for (temp = 0; temp < seen_count; temp++) {
                if (seen [temp] == ed)
                    break;
            }

            /* show more info the first time around */
            if (temp == seen_count) {
                u32 info = hc32_to_cpu (ohci, ed->hwINFO);
                struct list_head    *entry;
                unsigned        qlen = 0;

                /* qlen measured here in TDs, not urbs */
                list_for_each (entry, &ed->td_list)
                    qlen++;

                temp = scnprintf (next, size,
                    " (%cs dev%d ep%d%s-%s qlen %u"
                    " max %d %08x%s%s)",
                    (info & ED_LOWSPEED) ? 'l' : 'f',
                    info & 0x7f,
                    (info >> 7) & 0xf,
                    (info & ED_IN) ? "in" : "out",
                    (info & ED_ISO) ? "iso" : "int",
                    qlen,
                    0x03ff & (info >> 16),
                    info,
                    (info & ED_SKIP) ? " K" : "",
                    (ed->hwHeadP &
                        cpu_to_hc32(ohci, ED_H)) ?
                            " H" : "");
                size -= temp;
                next += temp;

                if (seen_count < DBG_SCHED_LIMIT)
                    seen [seen_count++] = ed;

                ed = ed->ed_next;

            } else {
                /* we've seen it and what's after */
                temp = 0;
                ed = NULL;
            }

        } while (ed);

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

    return PAGE_SIZE - size;
}
#undef DBG_SCHED_LIMIT

static ssize_t fill_registers_buffer(struct debug_buffer *buf)
{
    struct usb_hcd      *hcd;
    struct ohci_hcd     *ohci;
    struct ohci_regs __iomem *regs;
    unsigned long       flags;
    unsigned        temp, size;
    char            *next;
    u32         rdata;

    ohci = buf->ohci;
    hcd = ohci_to_hcd(ohci);
    regs = ohci->regs;
    next = buf->page;
    size = PAGE_SIZE;

    spin_lock_irqsave (&ohci->lock, flags);

    /* dump driver info, then registers in spec order */

    ohci_dbg_nosw(ohci, &next, &size,
        "bus %s, device %s\n"
        "%s\n"
        "%s\n",
        hcd->self.controller->bus->name,
        dev_name(hcd->self.controller),
        hcd->product_desc,
        hcd_name);

    if (!HCD_HW_ACCESSIBLE(hcd)) {
        size -= scnprintf (next, size,
            "SUSPENDED (no register access)\n");
        goto done;
    }

    ohci_dump_status(ohci, &next, &size);

    /* hcca */
    if (ohci->hcca)
        ohci_dbg_nosw(ohci, &next, &size,
            "hcca frame 0x%04x\n", ohci_frame_no(ohci));

    /* other registers mostly affect frame timings */
    rdata = ohci_readl (ohci, &regs->fminterval);
    temp = scnprintf (next, size,
            "fmintvl 0x%08x %sFSMPS=0x%04x FI=0x%04x\n",
            rdata, (rdata >> 31) ? "FIT " : "",
            (rdata >> 16) & 0xefff, rdata & 0xffff);
    size -= temp;
    next += temp;

    rdata = ohci_readl (ohci, &regs->fmremaining);
    temp = scnprintf (next, size, "fmremaining 0x%08x %sFR=0x%04x\n",
            rdata, (rdata >> 31) ? "FRT " : "",
            rdata & 0x3fff);
    size -= temp;
    next += temp;

    rdata = ohci_readl (ohci, &regs->periodicstart);
    temp = scnprintf (next, size, "periodicstart 0x%04x\n",
            rdata & 0x3fff);
    size -= temp;
    next += temp;

    rdata = ohci_readl (ohci, &regs->lsthresh);
    temp = scnprintf (next, size, "lsthresh 0x%04x\n",
            rdata & 0x3fff);
    size -= temp;
    next += temp;

    temp = scnprintf (next, size, "hub poll timer %s\n",
            HCD_POLL_RH(ohci_to_hcd(ohci)) ? "ON" : "off");
    size -= temp;
    next += temp;

    /* roothub */
    ohci_dump_roothub (ohci, 1, &next, &size);

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

    return PAGE_SIZE - size;
}

static struct debug_buffer *alloc_buffer(struct ohci_hcd *ohci,
                ssize_t (*fill_func)(struct debug_buffer *))
{
    struct debug_buffer *buf;

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

    if (buf) {
        buf->ohci = ohci;
        buf->fill_func = fill_func;
        mutex_init(&buf->mutex);
    }

    return buf;
}

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

    if (!buf->page)
        buf->page = (char *)get_zeroed_page(GFP_KERNEL);

    if (!buf->page) {
        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->page, buf->count);

out:
    return ret;

}

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

    if (buf) {
        if (buf->page)
            free_page((unsigned long)buf->page);
        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)
{
    file->private_data = alloc_buffer(inode->i_private,
                      fill_periodic_buffer);

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

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 inline void create_debug_files (struct ohci_hcd *ohci)
{
    struct usb_bus *bus = &ohci_to_hcd(ohci)->self;

    ohci->debug_dir = debugfs_create_dir(bus->bus_name, ohci_debug_root);
    if (!ohci->debug_dir)
        goto dir_error;

    ohci->debug_async = debugfs_create_file("async", S_IRUGO,
                        ohci->debug_dir, ohci,
                        &debug_async_fops);
    if (!ohci->debug_async)
        goto async_error;

    ohci->debug_periodic = debugfs_create_file("periodic", S_IRUGO,
                           ohci->debug_dir, ohci,
                           &debug_periodic_fops);
    if (!ohci->debug_periodic)
        goto periodic_error;

    ohci->debug_registers = debugfs_create_file("registers", S_IRUGO,
                            ohci->debug_dir, ohci,
                            &debug_registers_fops);
    if (!ohci->debug_registers)
        goto registers_error;

    ohci_dbg (ohci, "created debug files\n");
    return;

registers_error:
    debugfs_remove(ohci->debug_periodic);
periodic_error:
    debugfs_remove(ohci->debug_async);
async_error:
    debugfs_remove(ohci->debug_dir);
dir_error:
    ohci->debug_periodic = NULL;
    ohci->debug_async = NULL;
    ohci->debug_dir = NULL;
}

static inline void remove_debug_files (struct ohci_hcd *ohci)
{
    debugfs_remove(ohci->debug_registers);
    debugfs_remove(ohci->debug_periodic);
    debugfs_remove(ohci->debug_async);
    debugfs_remove(ohci->debug_dir);
}

#endif

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