sl811-hcd.c

usb driver for 2.6.17

	DBG("deschedule qh%d/%p branch %d\n", ep->period, ep, ep->branch);
	for (i = ep->branch; i < PERIODIC_SIZE; i += ep->period) {
		struct sl811h_ep	*temp;
		struct sl811h_ep	**prev = &sl811->periodic[i];

		while (*prev && ((temp = *prev) != ep))
			prev = &temp->next;
		if (*prev)
			*prev = ep->next;
		sl811->load[i] -= ep->load;
	}
	ep->branch = PERIODIC_SIZE;
	sl811->periodic_count--;
	sl811_to_hcd(sl811)->self.bandwidth_allocated
		-= ep->load / ep->period;
	if (ep == sl811->next_periodic)
		sl811->next_periodic = ep->next;

	/* we might turn SOFs back on again for the async schedule */
	if (sl811->periodic_count == 0)
		sofirq_off(sl811);
}

static void
done(struct sl811 *sl811, struct sl811h_ep *ep, u8 bank, struct pt_regs *regs)
{
	u8			status;
	struct urb		*urb;
	int			urbstat = -EINPROGRESS;

	if (unlikely(!ep))
		return;

	status = sl811_read(sl811, bank + SL11H_PKTSTATREG);

	urb = container_of(ep->hep->urb_list.next, struct urb, urb_list);

	/* we can safely ignore NAKs */
	if (status & SL11H_STATMASK_NAK) {
		// PACKET("...NAK_%02x qh%p\n", bank, ep);
		if (!ep->period)
			ep->nak_count++;
		ep->error_count = 0;

	/* ACK advances transfer, toggle, and maybe queue */
	} else if (status & SL11H_STATMASK_ACK) {
		struct usb_device	*udev = urb->dev;
		int			len;
		unsigned char		*buf;

		/* urb->iso_frame_desc is currently ignored here... */

		ep->nak_count = ep->error_count = 0;
		switch (ep->nextpid) {
		case USB_PID_OUT:
			// PACKET("...ACK/out_%02x qh%p\n", bank, ep);
			urb->actual_length += ep->length;
			usb_dotoggle(udev, ep->epnum, 1);
			if (urb->actual_length
					== urb->transfer_buffer_length) {
				if (usb_pipecontrol(urb->pipe))
					ep->nextpid = USB_PID_ACK;

				/* some bulk protocols terminate OUT transfers
				 * by a short packet, using ZLPs not padding.
				 */
				else if (ep->length < ep->maxpacket
						|| !(urb->transfer_flags
							& URB_ZERO_PACKET))
					urbstat = 0;
			}
			break;
		case USB_PID_IN:
			// PACKET("...ACK/in_%02x qh%p\n", bank, ep);
			buf = urb->transfer_buffer + urb->actual_length;
			prefetchw(buf);
			len = ep->maxpacket - sl811_read(sl811,
						bank + SL11H_XFERCNTREG);
			if (len > ep->length) {
				len = ep->length;
				urb->status = -EOVERFLOW;
			}
			urb->actual_length += len;
			sl811_read_buf(sl811, SL811HS_PACKET_BUF(bank == 0),
					buf, len);
			usb_dotoggle(udev, ep->epnum, 0);
			if (urb->actual_length == urb->transfer_buffer_length)
				urbstat = 0;
			else if (len < ep->maxpacket) {
				if (urb->transfer_flags & URB_SHORT_NOT_OK)
					urbstat = -EREMOTEIO;
				else
					urbstat = 0;
			}
			if (usb_pipecontrol(urb->pipe)
					&& (urbstat == -EREMOTEIO
						|| urbstat == 0)) {

				/* NOTE if the status stage STALLs (why?),
				 * this reports the wrong urb status.
				 */
				spin_lock(&urb->lock);
				if (urb->status == -EINPROGRESS)
					urb->status = urbstat;
				spin_unlock(&urb->lock);

				urb = NULL;
				ep->nextpid = USB_PID_ACK;
			}
			break;
		case USB_PID_SETUP:
			// PACKET("...ACK/setup_%02x qh%p\n", bank, ep);
			if (urb->transfer_buffer_length == urb->actual_length)
				ep->nextpid = USB_PID_ACK;
			else if (usb_pipeout(urb->pipe)) {
				usb_settoggle(udev, 0, 1, 1);
				ep->nextpid = USB_PID_OUT;
			} else {
				usb_settoggle(udev, 0, 0, 1);
				ep->nextpid = USB_PID_IN;
			}
			break;
		case USB_PID_ACK:
			// PACKET("...ACK/status_%02x qh%p\n", bank, ep);
			urbstat = 0;
			break;
		}

	/* STALL stops all transfers */
	} else if (status & SL11H_STATMASK_STALL) {
		PACKET("...STALL_%02x qh%p\n", bank, ep);
		ep->nak_count = ep->error_count = 0;
		urbstat = -EPIPE;

	/* error? retry, until "3 strikes" */
	} else if (++ep->error_count >= 3) {
		if (status & SL11H_STATMASK_TMOUT)
			urbstat = -ETIMEDOUT;
		else if (status & SL11H_STATMASK_OVF)
			urbstat = -EOVERFLOW;
		else
			urbstat = -EPROTO;
		ep->error_count = 0;
		PACKET("...3STRIKES_%02x %02x qh%p stat %d\n",
				bank, status, ep, urbstat);
	}

	if (urb && (urbstat != -EINPROGRESS || urb->status != -EINPROGRESS))
		finish_request(sl811, ep, urb, regs, urbstat);
}

static inline u8 checkdone(struct sl811 *sl811)
{
	u8	ctl;
	u8	irqstat = 0;

	if (sl811->active_a && time_before_eq(sl811->jiffies_a, jiffies)) {
		ctl = sl811_read(sl811, SL811_EP_A(SL11H_HOSTCTLREG));
		if (ctl & SL11H_HCTLMASK_ARM)
			sl811_write(sl811, SL811_EP_A(SL11H_HOSTCTLREG), 0);
		DBG("%s DONE_A: ctrl %02x sts %02x\n",
			(ctl & SL11H_HCTLMASK_ARM) ? "timeout" : "lost",
			ctl,
			sl811_read(sl811, SL811_EP_A(SL11H_PKTSTATREG)));
		irqstat |= SL11H_INTMASK_DONE_A;
	}
#ifdef	USE_B
	if (sl811->active_b && time_before_eq(sl811->jiffies_b, jiffies)) {
		ctl = sl811_read(sl811, SL811_EP_B(SL11H_HOSTCTLREG));
		if (ctl & SL11H_HCTLMASK_ARM)
			sl811_write(sl811, SL811_EP_B(SL11H_HOSTCTLREG), 0);
		DBG("%s DONE_B: ctrl %02x sts %02x\n",
			(ctl & SL11H_HCTLMASK_ARM) ? "timeout" : "lost",
			ctl,
			sl811_read(sl811, SL811_EP_B(SL11H_PKTSTATREG)));
		irqstat |= SL11H_INTMASK_DONE_A;
	}
#endif
	return irqstat;
}

static irqreturn_t sl811h_irq(struct usb_hcd *hcd, struct pt_regs *regs)
{
	struct sl811	*sl811 = hcd_to_sl811(hcd);
	u8		irqstat;
	irqreturn_t	ret = IRQ_NONE;
	unsigned	retries = 5;

	spin_lock(&sl811->lock);

retry:
	irqstat = sl811_read(sl811, SL11H_IRQ_STATUS) & ~SL11H_INTMASK_DP;
	if (irqstat) {
		sl811_write(sl811, SL11H_IRQ_STATUS, irqstat);
		irqstat &= sl811->irq_enable;
	}

#ifdef	QUIRK2
	/* this may no longer be necessary ... */
	if (irqstat == 0) {
		irqstat = checkdone(sl811);
		if (irqstat)
			sl811->stat_lost++;
	}
#endif

	/* USB packets, not necessarily handled in the order they're
	 * issued ... that's fine if they're different endpoints.
	 */
	if (irqstat & SL11H_INTMASK_DONE_A) {
		done(sl811, sl811->active_a, SL811_EP_A(SL811_HOST_BUF), regs);
		sl811->active_a = NULL;
		sl811->stat_a++;
	}
#ifdef USE_B
	if (irqstat & SL11H_INTMASK_DONE_B) {
		done(sl811, sl811->active_b, SL811_EP_B(SL811_HOST_BUF), regs);
		sl811->active_b = NULL;
		sl811->stat_b++;
	}
#endif
	if (irqstat & SL11H_INTMASK_SOFINTR) {
		unsigned index;

		index = sl811->frame++ % (PERIODIC_SIZE - 1);
		sl811->stat_sof++;

		/* be graceful about almost-inevitable periodic schedule
		 * overruns:  continue the previous frame's transfers iff
		 * this one has nothing scheduled.
		 */
		if (sl811->next_periodic) {
			// ERR("overrun to slot %d\n", index);
			sl811->stat_overrun++;
		}
		if (sl811->periodic[index])
			sl811->next_periodic = sl811->periodic[index];
	}

	/* khubd manages debouncing and wakeup */
	if (irqstat & SL11H_INTMASK_INSRMV) {
		sl811->stat_insrmv++;

		/* most stats are reset for each VBUS session */
		sl811->stat_wake = 0;
		sl811->stat_sof = 0;
		sl811->stat_a = 0;
		sl811->stat_b = 0;
		sl811->stat_lost = 0;

		sl811->ctrl1 = 0;
		sl811_write(sl811, SL11H_CTLREG1, sl811->ctrl1);

		sl811->irq_enable = SL11H_INTMASK_INSRMV;
		sl811_write(sl811, SL11H_IRQ_ENABLE, sl811->irq_enable);

		/* usbcore nukes other pending transactions on disconnect */
		if (sl811->active_a) {
			sl811_write(sl811, SL811_EP_A(SL11H_HOSTCTLREG), 0);
			finish_request(sl811, sl811->active_a,
				container_of(sl811->active_a
						->hep->urb_list.next,
					struct urb, urb_list),
				NULL, -ESHUTDOWN);
			sl811->active_a = NULL;
		}
#ifdef	USE_B
		if (sl811->active_b) {
			sl811_write(sl811, SL811_EP_B(SL11H_HOSTCTLREG), 0);
			finish_request(sl811, sl811->active_b,
				container_of(sl811->active_b
						->hep->urb_list.next,
					struct urb, urb_list),
				NULL, -ESHUTDOWN);
			sl811->active_b = NULL;
		}
#endif

		/* port status seems weird until after reset, so
		 * force the reset and make khubd clean up later.
		 */
		sl811->port1 |= (1 << USB_PORT_FEAT_C_CONNECTION)
				| (1 << USB_PORT_FEAT_CONNECTION);

	} else if (irqstat & SL11H_INTMASK_RD) {
		if (sl811->port1 & (1 << USB_PORT_FEAT_SUSPEND)) {
			DBG("wakeup\n");
			sl811->port1 |= 1 << USB_PORT_FEAT_C_SUSPEND;
			sl811->stat_wake++;
		} else
			irqstat &= ~SL11H_INTMASK_RD;
	}

	if (irqstat) {
		if (sl811->port1 & (1 << USB_PORT_FEAT_ENABLE))
			start_transfer(sl811);
		ret = IRQ_HANDLED;
		if (retries--)
			goto retry;
	}

	if (sl811->periodic_count == 0 && list_empty(&sl811->async))
		sofirq_off(sl811);
	sl811_write(sl811, SL11H_IRQ_ENABLE, sl811->irq_enable);

	spin_unlock(&sl811->lock);

	return ret;
}

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

/* usb 1.1 says max 90% of a frame is available for periodic transfers.
 * this driver doesn't promise that much since it's got to handle an
 * IRQ per packet; irq handling latencies also use up that time.
 *
 * NOTE:  the periodic schedule is a sparse tree, with the load for
 * each branch minimized.  see fig 3.5 in the OHCI spec for example.
 */
#define	MAX_PERIODIC_LOAD	500	/* out of 1000 usec */

static int balance(struct sl811 *sl811, u16 period, u16 load)
{
	int	i, branch = -ENOSPC;

	/* search for the least loaded schedule branch of that period
	 * which has enough bandwidth left unreserved.
	 */
	for (i = 0; i < period ; i++) {
		if (branch < 0 || sl811->load[branch] > sl811->load[i]) {
			int	j;

			for (j = i; j < PERIODIC_SIZE; j += period) {
				if ((sl811->load[j] + load)
						> MAX_PERIODIC_LOAD)
					break;
			}
			if (j < PERIODIC_SIZE)
				continue;
			branch = i;
		}
	}
	return branch;
}

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

static int sl811h_urb_enqueue(
	struct usb_hcd		*hcd,
	struct usb_host_endpoint *hep,
	struct urb		*urb,
	gfp_t			mem_flags
) {
	struct sl811		*sl811 = hcd_to_sl811(hcd);
	struct usb_device	*udev = urb->dev;
	unsigned int		pipe = urb->pipe;
	int			is_out = !usb_pipein(pipe);
	int			type = usb_pipetype(pipe);
	int			epnum = usb_pipeendpoint(pipe);
	struct sl811h_ep	*ep = NULL;
	unsigned long		flags;
	int			i;
	int			retval = 0;

#ifdef	DISABLE_ISO
	if (type == PIPE_ISOCHRONOUS)
		return -ENOSPC;
#endif

	/* avoid all allocations within spinlocks */
	if (!hep->hcpriv)
		ep = kzalloc(sizeof *ep, mem_flags);

	spin_lock_irqsave(&sl811->lock, flags);

	/* don't submit to a dead or disabled port */
	if (!(sl811->port1 & (1 << USB_PORT_FEAT_ENABLE))
			|| !HC_IS_RUNNING(hcd->state)) {
		retval = -ENODEV;
		kfree(ep);
		goto fail;
	}

	if (hep->hcpriv) {
		kfree(ep);
		ep = hep->hcpriv;
	} else if (!ep) {
		retval = -ENOMEM;
		goto fail;

	} else {
		INIT_LIST_HEAD(&ep->schedule);
		ep->udev = udev;
		ep->epnum = epnum;
		ep->maxpacket = usb_maxpacket(udev, urb->pipe, is_out);
		ep->defctrl = SL11H_HCTLMASK_ARM | SL11H_HCTLMASK_ENABLE;
		usb_settoggle(udev, epnum, is_out, 0);

		if (type == PIPE_CONTROL)
			ep->nextpid = USB_PID_SETUP;
		else if (is_out)
			ep->nextpid = USB_PID_OUT;
		else
			ep->nextpid = USB_PID_IN;

		if (ep->maxpacket > H_MAXPACKET) {
			/* iso packets up to 240 bytes could work... */
			DBG("dev %d ep%d maxpacket %d\n",
				udev->devnum, epnum, ep->maxpacket);
			retval = -EINVAL;
			goto fail;
		}

		if (udev->speed == USB_SPEED_LOW) {
			/* send preamble for external hub? */
			if (!(sl811->ctrl1 & SL11H_CTL1MASK_LSPD))
				ep->defctrl |= SL11H_HCTLMASK_PREAMBLE;
		}
		switch (type) {
		case PIPE_ISOCHRONOUS:
		case PIPE_INTERRUPT:
			if (urb->interval > PERIODIC_SIZE)
				urb->interval = PERIODIC_SIZE;
			ep->period = urb->interval;
			ep->branch = PERIODIC_SIZE;
			if (type == PIPE_ISOCHRONOUS)
				ep->defctrl |= SL11H_HCTLMASK_ISOCH;
			ep->load = usb_calc_bus_time(udev->speed, !is_out,
				(type == PIPE_ISOCHRONOUS),
				usb_maxpacket(udev, pipe, is_out))
					/ 1000;
			break;
		}

		ep->hep = hep;
		hep->hcpriv = ep;
	}

	/* maybe put endpoint into schedule */
	switch (type) {
	case PIPE_CONTROL:
	case PIPE_BULK:
		if (list_empty(&ep->schedule))
			list_add_tail(&ep->schedule, &sl811->async);
		break;
	case PIPE_ISOCHRONOUS:
	case PIPE_INTERRUPT:
		urb->interval = ep->period;
		if (ep->branch < PERIODIC_SIZE) {
			/* NOTE:  the phase is correct here, but the value
			 * needs offsetting by the transfer queue depth.
			 * All current drivers ignore start_frame, so this
			 * is unlikely to ever matter...
			 */
			urb->start_frame = (sl811->frame & (PERIODIC_SIZE - 1))
						+ ep->branch;
			break;
		}

		retval = balance(sl811, ep->period, ep->load);
		if (retval < 0)
			goto fail;
		ep->branch = retval;