net2280.c

ARM S3C2410 USB SLAVE LINUX驱动

		return NULL;
	*dma = DMA_ADDR_INVALID;

#if	defined(USE_KMALLOC)
	retval = kmalloc(bytes, gfp_flags);
	if (retval)
		*dma = virt_to_phys(retval);
#else
	if (ep->dma) {
		/* the main problem with this call is that it wastes memory
		 * on typical 1/N page allocations: it allocates 1-N pages.
		 */
#warning Using dma_alloc_coherent even with buffers smaller than a page.
		retval = dma_alloc_coherent(&ep->dev->pdev->dev,
				bytes, dma, gfp_flags);
	} else
		retval = kmalloc(bytes, gfp_flags);
#endif
	return retval;
}

static void
net2280_free_buffer (
	struct usb_ep *_ep,
	void *buf,
	dma_addr_t dma,
	unsigned bytes
) {
	/* free memory into the right allocator */
#ifndef	USE_KMALLOC
	if (dma != DMA_ADDR_INVALID) {
		struct net2280_ep	*ep;

		ep = container_of(_ep, struct net2280_ep, ep);
		if (!_ep)
			return;
		dma_free_coherent(&ep->dev->pdev->dev, bytes, buf, dma);
	} else
#endif
		kfree (buf);
}

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

/* load a packet into the fifo we use for usb IN transfers.
 * works for all endpoints.
 *
 * NOTE: pio with ep-a..ep-d could stuff multiple packets into the fifo
 * at a time, but this code is simpler because it knows it only writes
 * one packet.  ep-a..ep-d should use dma instead.
 */
static void
write_fifo (struct net2280_ep *ep, struct usb_request *req)
{
	struct net2280_ep_regs	__iomem *regs = ep->regs;
	u8			*buf;
	u32			tmp;
	unsigned		count, total;

	/* INVARIANT:  fifo is currently empty. (testable) */

	if (req) {
		buf = req->buf + req->actual;
		prefetch (buf);
		total = req->length - req->actual;
	} else {
		total = 0;
		buf = NULL;
	}

	/* write just one packet at a time */
	count = ep->ep.maxpacket;
	if (count > total)	/* min() cannot be used on a bitfield */
		count = total;

	VDEBUG (ep->dev, "write %s fifo (IN) %d bytes%s req %p\n",
			ep->ep.name, count,
			(count != ep->ep.maxpacket) ? " (short)" : "",
			req);
	while (count >= 4) {
		/* NOTE be careful if you try to align these. fifo lines
		 * should normally be full (4 bytes) and successive partial
		 * lines are ok only in certain cases.
		 */
		tmp = get_unaligned ((u32 *)buf);
		cpu_to_le32s (&tmp);
		writel (tmp, &regs->ep_data);
		buf += 4;
		count -= 4;
	}

	/* last fifo entry is "short" unless we wrote a full packet.
	 * also explicitly validate last word in (periodic) transfers
	 * when maxpacket is not a multiple of 4 bytes.
	 */
	if (count || total < ep->ep.maxpacket) {
		tmp = count ? get_unaligned ((u32 *)buf) : count;
		cpu_to_le32s (&tmp);
		set_fifo_bytecount (ep, count & 0x03);
		writel (tmp, &regs->ep_data);
	}

	/* pci writes may still be posted */
}

/* work around erratum 0106: PCI and USB race over the OUT fifo.
 * caller guarantees chiprev 0100, out endpoint is NAKing, and
 * there's no real data in the fifo.
 *
 * NOTE:  also used in cases where that erratum doesn't apply:
 * where the host wrote "too much" data to us.
 */
static void out_flush (struct net2280_ep *ep)
{
	u32	__iomem *statp;
	u32	tmp;

	ASSERT_OUT_NAKING (ep);

	statp = &ep->regs->ep_stat;
	writel (  (1 << DATA_OUT_PING_TOKEN_INTERRUPT)
		| (1 << DATA_PACKET_RECEIVED_INTERRUPT)
		, statp);
	writel ((1 << FIFO_FLUSH), statp);
	mb ();
	tmp = readl (statp);
	if (tmp & (1 << DATA_OUT_PING_TOKEN_INTERRUPT)
			/* high speed did bulk NYET; fifo isn't filling */
			&& ep->dev->gadget.speed == USB_SPEED_FULL) {
		unsigned	usec;

		usec = 50;		/* 64 byte bulk/interrupt */
		handshake (statp, (1 << USB_OUT_PING_NAK_SENT),
				(1 << USB_OUT_PING_NAK_SENT), usec);
		/* NAK done; now CLEAR_NAK_OUT_PACKETS is safe */
	}
}

/* unload packet(s) from the fifo we use for usb OUT transfers.
 * returns true iff the request completed, because of short packet
 * or the request buffer having filled with full packets.
 *
 * for ep-a..ep-d this will read multiple packets out when they
 * have been accepted.
 */
static int
read_fifo (struct net2280_ep *ep, struct net2280_request *req)
{
	struct net2280_ep_regs	__iomem *regs = ep->regs;
	u8			*buf = req->req.buf + req->req.actual;
	unsigned		count, tmp, is_short;
	unsigned		cleanup = 0, prevent = 0;

	/* erratum 0106 ... packets coming in during fifo reads might
	 * be incompletely rejected.  not all cases have workarounds.
	 */
	if (ep->dev->chiprev == 0x0100
			&& ep->dev->gadget.speed == USB_SPEED_FULL) {
		udelay (1);
		tmp = readl (&ep->regs->ep_stat);
		if ((tmp & (1 << NAK_OUT_PACKETS)))
			cleanup = 1;
		else if ((tmp & (1 << FIFO_FULL))) {
			start_out_naking (ep);
			prevent = 1;
		}
		/* else: hope we don't see the problem */
	}

	/* never overflow the rx buffer. the fifo reads packets until
	 * it sees a short one; we might not be ready for them all.
	 */
	prefetchw (buf);
	count = readl (&regs->ep_avail);
	if (unlikely (count == 0)) {
		udelay (1);
		tmp = readl (&ep->regs->ep_stat);
		count = readl (&regs->ep_avail);
		/* handled that data already? */
		if (count == 0 && (tmp & (1 << NAK_OUT_PACKETS)) == 0)
			return 0;
	}

	tmp = req->req.length - req->req.actual;
	if (count > tmp) {
		/* as with DMA, data overflow gets flushed */
		if ((tmp % ep->ep.maxpacket) != 0) {
			ERROR (ep->dev,
				"%s out fifo %d bytes, expected %d\n",
				ep->ep.name, count, tmp);
			req->req.status = -EOVERFLOW;
			cleanup = 1;
			/* NAK_OUT_PACKETS will be set, so flushing is safe;
			 * the next read will start with the next packet
			 */
		} /* else it's a ZLP, no worries */
		count = tmp;
	}
	req->req.actual += count;

	is_short = (count == 0) || ((count % ep->ep.maxpacket) != 0);

	VDEBUG (ep->dev, "read %s fifo (OUT) %d bytes%s%s%s req %p %d/%d\n",
			ep->ep.name, count, is_short ? " (short)" : "",
			cleanup ? " flush" : "", prevent ? " nak" : "",
			req, req->req.actual, req->req.length);

	while (count >= 4) {
		tmp = readl (&regs->ep_data);
		cpu_to_le32s (&tmp);
		put_unaligned (tmp, (u32 *)buf);
		buf += 4;
		count -= 4;
	}
	if (count) {
		tmp = readl (&regs->ep_data);
		/* LE conversion is implicit here: */
		do {
			*buf++ = (u8) tmp;
			tmp >>= 8;
		} while (--count);
	}
	if (cleanup)
		out_flush (ep);
	if (prevent) {
		writel ((1 << CLEAR_NAK_OUT_PACKETS), &ep->regs->ep_rsp);
		(void) readl (&ep->regs->ep_rsp);
	}

	return is_short || ((req->req.actual == req->req.length)
				&& !req->req.zero);
}

/* fill out dma descriptor to match a given request */
static void
fill_dma_desc (struct net2280_ep *ep, struct net2280_request *req, int valid)
{
	struct net2280_dma	*td = req->td;
	u32			dmacount = req->req.length;

	/* don't let DMA continue after a short OUT packet,
	 * so overruns can't affect the next transfer.
	 * in case of overruns on max-size packets, we can't
	 * stop the fifo from filling but we can flush it.
	 */
	if (ep->is_in)
		dmacount |= (1 << DMA_DIRECTION);
	else if ((dmacount % ep->ep.maxpacket) != 0)
		dmacount |= (1 << END_OF_CHAIN);

	req->valid = valid;
	if (valid)
		dmacount |= (1 << VALID_BIT);
	if (likely(!req->req.no_interrupt || !use_dma_chaining))
		dmacount |= (1 << DMA_DONE_INTERRUPT_ENABLE);

	/* td->dmadesc = previously set by caller */
	td->dmaaddr = cpu_to_le32 (req->req.dma);

	/* 2280 may be polling VALID_BIT through ep->dma->dmadesc */
	wmb ();
	td->dmacount = cpu_to_le32p (&dmacount);
}

static const u32 dmactl_default =
		  (1 << DMA_SCATTER_GATHER_DONE_INTERRUPT)
		| (1 << DMA_CLEAR_COUNT_ENABLE)
		/* erratum 0116 workaround part 1 (use POLLING) */
		| (POLL_100_USEC << DESCRIPTOR_POLLING_RATE)
		| (1 << DMA_VALID_BIT_POLLING_ENABLE)
		| (1 << DMA_VALID_BIT_ENABLE)
		| (1 << DMA_SCATTER_GATHER_ENABLE)
		/* erratum 0116 workaround part 2 (no AUTOSTART) */
		| (1 << DMA_ENABLE);

static inline void spin_stop_dma (struct net2280_dma_regs __iomem *dma)
{
	handshake (&dma->dmactl, (1 << DMA_ENABLE), 0, 50);
}

static inline void stop_dma (struct net2280_dma_regs __iomem *dma)
{
	writel (readl (&dma->dmactl) & ~(1 << DMA_ENABLE), &dma->dmactl);
	spin_stop_dma (dma);
}

static void start_queue (struct net2280_ep *ep, u32 dmactl, u32 td_dma)
{
	struct net2280_dma_regs	__iomem *dma = ep->dma;

	writel ((1 << VALID_BIT) | (ep->is_in << DMA_DIRECTION),
			&dma->dmacount);
	writel (readl (&dma->dmastat), &dma->dmastat);

	writel (td_dma, &dma->dmadesc);
	writel (dmactl, &dma->dmactl);

	/* erratum 0116 workaround part 3:  pci arbiter away from net2280 */
	(void) readl (&ep->dev->pci->pcimstctl);

	writel ((1 << DMA_START), &dma->dmastat);

	if (!ep->is_in)
		stop_out_naking (ep);
}

static void start_dma (struct net2280_ep *ep, struct net2280_request *req)
{
	u32			tmp;
	struct net2280_dma_regs	__iomem *dma = ep->dma;

	/* FIXME can't use DMA for ZLPs */

	/* on this path we "know" there's no dma active (yet) */
	WARN_ON (readl (&dma->dmactl) & (1 << DMA_ENABLE));
	writel (0, &ep->dma->dmactl);

	/* previous OUT packet might have been short */
	if (!ep->is_in && ((tmp = readl (&ep->regs->ep_stat))
		 		& (1 << NAK_OUT_PACKETS)) != 0) {
		writel ((1 << SHORT_PACKET_TRANSFERRED_INTERRUPT),
			&ep->regs->ep_stat);

		tmp = readl (&ep->regs->ep_avail);
		if (tmp) {
			writel (readl (&dma->dmastat), &dma->dmastat);

			/* transfer all/some fifo data */
			writel (req->req.dma, &dma->dmaaddr);
			tmp = min (tmp, req->req.length);

			/* dma irq, faking scatterlist status */
			req->td->dmacount = cpu_to_le32 (req->req.length - tmp);
			writel ((1 << DMA_DONE_INTERRUPT_ENABLE)
				| tmp, &dma->dmacount);
			req->td->dmadesc = 0;
			req->valid = 1;

			writel ((1 << DMA_ENABLE), &dma->dmactl);
			writel ((1 << DMA_START), &dma->dmastat);
			return;
		}
	}

	tmp = dmactl_default;

	/* force packet boundaries between dma requests, but prevent the
	 * controller from automagically writing a last "short" packet
	 * (zero length) unless the driver explicitly said to do that.
	 */
	if (ep->is_in) {
		if (likely ((req->req.length % ep->ep.maxpacket) != 0
				|| req->req.zero)) {
			tmp |= (1 << DMA_FIFO_VALIDATE);
			ep->in_fifo_validate = 1;
		} else
			ep->in_fifo_validate = 0;
	}

	/* init req->td, pointing to the current dummy */
	req->td->dmadesc = cpu_to_le32 (ep->td_dma);
	fill_dma_desc (ep, req, 1);

	if (!use_dma_chaining)
		req->td->dmacount |= __constant_cpu_to_le32 (1 << END_OF_CHAIN);

	start_queue (ep, tmp, req->td_dma);
}

static inline void
queue_dma (struct net2280_ep *ep, struct net2280_request *req, int valid)
{
	struct net2280_dma	*end;
	dma_addr_t		tmp;

	/* swap new dummy for old, link; fill and maybe activate */
	end = ep->dummy;
	ep->dummy = req->td;
	req->td = end;

	tmp = ep->td_dma;
	ep->td_dma = req->td_dma;
	req->td_dma = tmp;

	end->dmadesc = cpu_to_le32 (ep->td_dma);

	fill_dma_desc (ep, req, valid);
}

static void
done (struct net2280_ep *ep, struct net2280_request *req, int status)
{
	struct net2280		*dev;
	unsigned		stopped = ep->stopped;

	list_del_init (&req->queue);

	if (req->req.status == -EINPROGRESS)
		req->req.status = status;
	else
		status = req->req.status;

	dev = ep->dev;
	if (req->mapped) {
		pci_unmap_single (dev->pdev, req->req.dma, req->req.length,
			ep->is_in ? PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);
		req->req.dma = DMA_ADDR_INVALID;
		req->mapped = 0;
	}

	if (status && status != -ESHUTDOWN)
		VDEBUG (dev, "complete %s req %p stat %d len %u/%u\n",
			ep->ep.name, &req->req, status,
			req->req.actual, req->req.length);

	/* don't modify queue heads during completion callback */
	ep->stopped = 1;
	spin_unlock (&dev->lock);
	req->req.complete (&ep->ep, &req->req);
	spin_lock (&dev->lock);
	ep->stopped = stopped;
}

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

static int
net2280_queue (struct usb_ep *_ep, struct usb_request *_req, unsigned gfp_flags)
{
	struct net2280_request	*req;
	struct net2280_ep	*ep;
	struct net2280		*dev;
	unsigned long		flags;

	/* we always require a cpu-view buffer, so that we can
	 * always use pio (as fallback or whatever).
	 */
	req = container_of (_req, struct net2280_request, req);
	if (!_req || !_req->complete || !_req->buf
			|| !list_empty (&req->queue))
		return -EINVAL;
	if (_req->length > (~0 & DMA_BYTE_COUNT_MASK))
		return -EDOM;
	ep = container_of (_ep, struct net2280_ep, ep);
	if (!_ep || (!ep->desc && ep->num != 0))
		return -EINVAL;
	dev = ep->dev;
	if (!dev->driver || dev->gadget.speed == USB_SPEED_UNKNOWN)
		return -ESHUTDOWN;

	/* FIXME implement PIO fallback for ZLPs with DMA */
	if (ep->dma && _req->length == 0)
		return -EOPNOTSUPP;

	/* set up dma mapping in case the caller didn't */
	if (ep->dma && _req->dma == DMA_ADDR_INVALID) {
		_req->dma = pci_map_single (dev->pdev, _req->buf, _req->length,
			ep->is_in ? PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);
		req->mapped = 1;
	}

#if 0
	VDEBUG (dev, "%s queue req %p, len %d buf %p\n",
			_ep->name, _req, _req->length, _req->buf);
#endif

	spin_lock_irqsave (&dev->lock, flags);

	_req->status = -EINPROGRESS;
	_req->actual = 0;

	/* kickstart this i/o queue? */
	if (list_empty (&ep->queue) && !ep->stopped) {
		/* use DMA if the endpoint supports it, else pio */