omap_udc.c

ARM S3C2410 USB SLAVE LINUX驱动

	u8		*buf;
	unsigned	count, avail;
	int		is_last;

	buf = req->req.buf + req->req.actual;
	prefetchw(buf);

	for (;;) {
		u16	ep_stat = UDC_STAT_FLG_REG;

		is_last = 0;
		if (ep_stat & FIFO_EMPTY) {
			if (!ep->double_buf)
				break;
			ep->fnf = 1;
		}
		if (ep_stat & UDC_EP_HALTED)
			break;

		if (ep_stat & UDC_FIFO_FULL)
			avail = ep->ep.maxpacket;
		else  {
			avail = UDC_RXFSTAT_REG;
			ep->fnf = ep->double_buf;
		}
		count = read_packet(buf, req, avail);

		/* partial packet reads may not be errors */
		if (count < ep->ep.maxpacket) {
			is_last = 1;
			/* overflowed this request?  flush extra data */
			if (count != avail) {
				req->req.status = -EOVERFLOW;
				avail -= count;
				while (avail--)
					(void) *(volatile u8 *)&UDC_DATA_REG;
			}
		} else if (req->req.length == req->req.actual)
			is_last = 1;
		else
			is_last = 0;

		if (!ep->bEndpointAddress)
			break;
		if (is_last)
			done(ep, req, 0);
		break;
	}
	return is_last;
}

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

static inline dma_addr_t dma_csac(unsigned lch)
{
	dma_addr_t	csac;

	/* omap 3.2/3.3 erratum: sometimes 0 is returned if CSAC/CDAC is
	 * read before the DMA controller finished disabling the channel.
	 */
	csac = omap_readw(OMAP_DMA_CSAC(lch));
	if (csac == 0)
		csac = omap_readw(OMAP_DMA_CSAC(lch));
	return csac;
}

static inline dma_addr_t dma_cdac(unsigned lch)
{
	dma_addr_t	cdac;

	/* omap 3.2/3.3 erratum: sometimes 0 is returned if CSAC/CDAC is
	 * read before the DMA controller finished disabling the channel.
	 */
	cdac = omap_readw(OMAP_DMA_CDAC(lch));
	if (cdac == 0)
		cdac = omap_readw(OMAP_DMA_CDAC(lch));
	return cdac;
}

static u16 dma_src_len(struct omap_ep *ep, dma_addr_t start)
{
	dma_addr_t	end;

	/* IN-DMA needs this on fault/cancel paths, so 15xx misreports
	 * the last transfer's bytecount by more than a FIFO's worth.
	 */
	if (cpu_is_omap15xx())
		return 0;

	end = dma_csac(ep->lch);
	if (end == ep->dma_counter)
		return 0;

	end |= start & (0xffff << 16);
	if (end < start)
		end += 0x10000;
	return end - start;
}

#define DMA_DEST_LAST(x) (cpu_is_omap15xx() \
		? omap_readw(OMAP_DMA_CSAC(x)) /* really: CPC */ \
		: dma_cdac(x))

static u16 dma_dest_len(struct omap_ep *ep, dma_addr_t start)
{
	dma_addr_t	end;

	end = DMA_DEST_LAST(ep->lch);
	if (end == ep->dma_counter)
		return 0;

	end |= start & (0xffff << 16);
	if (cpu_is_omap15xx())
		end++;
	if (end < start)
		end += 0x10000;
	return end - start;
}


/* Each USB transfer request using DMA maps to one or more DMA transfers.
 * When DMA completion isn't request completion, the UDC continues with
 * the next DMA transfer for that USB transfer.
 */

static void next_in_dma(struct omap_ep *ep, struct omap_req *req)
{
	u16		txdma_ctrl;
	unsigned	length = req->req.length - req->req.actual;
	const int	sync_mode = cpu_is_omap15xx()
				? OMAP_DMA_SYNC_FRAME
				: OMAP_DMA_SYNC_ELEMENT;

	/* measure length in either bytes or packets */
	if ((cpu_is_omap16xx() && length <= UDC_TXN_TSC)
			|| (cpu_is_omap15xx() && length < ep->maxpacket)) {
		txdma_ctrl = UDC_TXN_EOT | length;
		omap_set_dma_transfer_params(ep->lch, OMAP_DMA_DATA_TYPE_S8,
				length, 1, sync_mode);
	} else {
		length = min(length / ep->maxpacket,
				(unsigned) UDC_TXN_TSC + 1);
 		txdma_ctrl = length;
		omap_set_dma_transfer_params(ep->lch, OMAP_DMA_DATA_TYPE_S16,
				ep->ep.maxpacket >> 1, length, sync_mode);
		length *= ep->maxpacket;
	}
	omap_set_dma_src_params(ep->lch, OMAP_DMA_PORT_EMIFF,
		OMAP_DMA_AMODE_POST_INC, req->req.dma + req->req.actual);

	omap_start_dma(ep->lch);
	ep->dma_counter = dma_csac(ep->lch);
	UDC_DMA_IRQ_EN_REG |= UDC_TX_DONE_IE(ep->dma_channel);
	UDC_TXDMA_REG(ep->dma_channel) = UDC_TXN_START | txdma_ctrl;
	req->dma_bytes = length;
}

static void finish_in_dma(struct omap_ep *ep, struct omap_req *req, int status)
{
	if (status == 0) {
		req->req.actual += req->dma_bytes;

		/* return if this request needs to send data or zlp */
		if (req->req.actual < req->req.length)
			return;
		if (req->req.zero
				&& req->dma_bytes != 0
				&& (req->req.actual % ep->maxpacket) == 0)
			return;
	} else
		req->req.actual += dma_src_len(ep, req->req.dma
							+ req->req.actual);

	/* tx completion */
	omap_stop_dma(ep->lch);
	UDC_DMA_IRQ_EN_REG &= ~UDC_TX_DONE_IE(ep->dma_channel);
	done(ep, req, status);
}

static void next_out_dma(struct omap_ep *ep, struct omap_req *req)
{
	unsigned packets;

	/* NOTE:  we filtered out "short reads" before, so we know
	 * the buffer has only whole numbers of packets.
	 */

	/* set up this DMA transfer, enable the fifo, start */
	packets = (req->req.length - req->req.actual) / ep->ep.maxpacket;
	packets = min(packets, (unsigned)UDC_RXN_TC + 1);
	req->dma_bytes = packets * ep->ep.maxpacket;
	omap_set_dma_transfer_params(ep->lch, OMAP_DMA_DATA_TYPE_S16,
			ep->ep.maxpacket >> 1, packets,
			OMAP_DMA_SYNC_ELEMENT);
	omap_set_dma_dest_params(ep->lch, OMAP_DMA_PORT_EMIFF,
		OMAP_DMA_AMODE_POST_INC, req->req.dma + req->req.actual);
	ep->dma_counter = DMA_DEST_LAST(ep->lch);

	UDC_RXDMA_REG(ep->dma_channel) = UDC_RXN_STOP | (packets - 1);
	UDC_DMA_IRQ_EN_REG |= UDC_RX_EOT_IE(ep->dma_channel);
	UDC_EP_NUM_REG = (ep->bEndpointAddress & 0xf);
	UDC_CTRL_REG = UDC_SET_FIFO_EN;

	omap_start_dma(ep->lch);
}

static void
finish_out_dma(struct omap_ep *ep, struct omap_req *req, int status)
{
	u16	count;

	if (status == 0)
		ep->dma_counter = (u16) (req->req.dma + req->req.actual);
	count = dma_dest_len(ep, req->req.dma + req->req.actual);
	count += req->req.actual;
	if (count <= req->req.length)
		req->req.actual = count;

	if (count != req->dma_bytes || status)
		omap_stop_dma(ep->lch);

	/* if this wasn't short, request may need another transfer */
	else if (req->req.actual < req->req.length)
		return;

	/* rx completion */
	UDC_DMA_IRQ_EN_REG &= ~UDC_RX_EOT_IE(ep->dma_channel);
	done(ep, req, status);
}

static void dma_irq(struct omap_udc *udc, u16 irq_src)
{
	u16		dman_stat = UDC_DMAN_STAT_REG;
	struct omap_ep	*ep;
	struct omap_req	*req;

	/* IN dma: tx to host */
	if (irq_src & UDC_TXN_DONE) {
		ep = &udc->ep[16 + UDC_DMA_TX_SRC(dman_stat)];
		ep->irqs++;
		/* can see TXN_DONE after dma abort */
		if (!list_empty(&ep->queue)) {
			req = container_of(ep->queue.next,
						struct omap_req, queue);
			finish_in_dma(ep, req, 0);
		}
		UDC_IRQ_SRC_REG = UDC_TXN_DONE;

		if (!list_empty (&ep->queue)) {
			req = container_of(ep->queue.next,
					struct omap_req, queue);
			next_in_dma(ep, req);
		}
	}

	/* OUT dma: rx from host */
	if (irq_src & UDC_RXN_EOT) {
		ep = &udc->ep[UDC_DMA_RX_SRC(dman_stat)];
		ep->irqs++;
		/* can see RXN_EOT after dma abort */
		if (!list_empty(&ep->queue)) {
			req = container_of(ep->queue.next,
					struct omap_req, queue);
			finish_out_dma(ep, req, 0);
		}
		UDC_IRQ_SRC_REG = UDC_RXN_EOT;

		if (!list_empty (&ep->queue)) {
			req = container_of(ep->queue.next,
					struct omap_req, queue);
			next_out_dma(ep, req);
		}
	}

	if (irq_src & UDC_RXN_CNT) {
		ep = &udc->ep[UDC_DMA_RX_SRC(dman_stat)];
		ep->irqs++;
		/* omap15xx does this unasked... */
		VDBG("%s, RX_CNT irq?\n", ep->ep.name);
		UDC_IRQ_SRC_REG = UDC_RXN_CNT;
	}
}

static void dma_error(int lch, u16 ch_status, void *data)
{
	struct omap_ep	*ep = data;

	/* if ch_status & OMAP_DMA_DROP_IRQ ... */
	/* if ch_status & OMAP_DMA_TOUT_IRQ ... */
	ERR("%s dma error, lch %d status %02x\n", ep->ep.name, lch, ch_status);

	/* complete current transfer ... */
}

static void dma_channel_claim(struct omap_ep *ep, unsigned channel)
{
	u16	reg;
	int	status, restart, is_in;

	is_in = ep->bEndpointAddress & USB_DIR_IN;
	if (is_in)
		reg = UDC_TXDMA_CFG_REG;
	else
		reg = UDC_RXDMA_CFG_REG;
	reg |= UDC_DMA_REQ;		/* "pulse" activated */

	ep->dma_channel = 0;
	ep->lch = -1;
	if (channel == 0 || channel > 3) {
		if ((reg & 0x0f00) == 0)
			channel = 3;
		else if ((reg & 0x00f0) == 0)
			channel = 2;
		else if ((reg & 0x000f) == 0)	/* preferred for ISO */
			channel = 1;
		else {
			status = -EMLINK;
			goto just_restart;
		}
	}
	reg |= (0x0f & ep->bEndpointAddress) << (4 * (channel - 1));
	ep->dma_channel = channel;

	if (is_in) {
		status = omap_request_dma(OMAP_DMA_USB_W2FC_TX0 - 1 + channel,
			ep->ep.name, dma_error, ep, &ep->lch);
		if (status == 0) {
			UDC_TXDMA_CFG_REG = reg;
			/* EMIFF */
			omap_set_dma_src_burst_mode(ep->lch,
						OMAP_DMA_DATA_BURST_4);
			omap_set_dma_src_data_pack(ep->lch, 1);
			/* TIPB */
			omap_set_dma_dest_params(ep->lch,
				OMAP_DMA_PORT_TIPB,
				OMAP_DMA_AMODE_CONSTANT,
				(unsigned long) io_v2p((u32)&UDC_DATA_DMA_REG));
		}
	} else {
		status = omap_request_dma(OMAP_DMA_USB_W2FC_RX0 - 1 + channel,
			ep->ep.name, dma_error, ep, &ep->lch);
		if (status == 0) {
			UDC_RXDMA_CFG_REG = reg;
			/* TIPB */
			omap_set_dma_src_params(ep->lch,
				OMAP_DMA_PORT_TIPB,
				OMAP_DMA_AMODE_CONSTANT,
				(unsigned long) io_v2p((u32)&UDC_DATA_DMA_REG));
			/* EMIFF */
			omap_set_dma_dest_burst_mode(ep->lch,
						OMAP_DMA_DATA_BURST_4);
			omap_set_dma_dest_data_pack(ep->lch, 1);
		}
	}
	if (status)
		ep->dma_channel = 0;
	else {
		ep->has_dma = 1;
		omap_disable_dma_irq(ep->lch, OMAP_DMA_BLOCK_IRQ);

		/* channel type P: hw synch (fifo) */
		if (!cpu_is_omap15xx())
			omap_writew(2, OMAP_DMA_LCH_CTRL(ep->lch));
	}

just_restart:
	/* restart any queue, even if the claim failed  */
	restart = !ep->stopped && !list_empty(&ep->queue);

	if (status)
		DBG("%s no dma channel: %d%s\n", ep->ep.name, status,
			restart ? " (restart)" : "");
	else
		DBG("%s claimed %cxdma%d lch %d%s\n", ep->ep.name,
			is_in ? 't' : 'r',
			ep->dma_channel - 1, ep->lch,
			restart ? " (restart)" : "");

	if (restart) {
		struct omap_req	*req;
		req = container_of(ep->queue.next, struct omap_req, queue);
		if (ep->has_dma)
			(is_in ? next_in_dma : next_out_dma)(ep, req);
		else {
			use_ep(ep, UDC_EP_SEL);
			(is_in ? write_fifo : read_fifo)(ep, req);
			deselect_ep();
			if (!is_in) {
				UDC_CTRL_REG = UDC_SET_FIFO_EN;
				ep->ackwait = 1 + ep->double_buf;
			}
			/* IN: 6 wait states before it'll tx */
		}
	}
}

static void dma_channel_release(struct omap_ep *ep)
{
	int		shift = 4 * (ep->dma_channel - 1);
	u16		mask = 0x0f << shift;
	struct omap_req	*req;
	int		active;

	/* abort any active usb transfer request */
	if (!list_empty(&ep->queue))
		req = container_of(ep->queue.next, struct omap_req, queue);
	else
		req = NULL;

	active = ((1 << 7) & omap_readl(OMAP_DMA_CCR(ep->lch))) != 0;

	DBG("%s release %s %cxdma%d %p\n", ep->ep.name,
			active ? "active" : "idle",
			(ep->bEndpointAddress & USB_DIR_IN) ? 't' : 'r',
			ep->dma_channel - 1, req);

	/* NOTE: re-setting RX_REQ/TX_REQ because of a chip bug (before
	 * OMAP 1710 ES2.0) where reading the DMA_CFG can clear them.
	 */

	/* wait till current packet DMA finishes, and fifo empties */
	if (ep->bEndpointAddress & USB_DIR_IN) {
		UDC_TXDMA_CFG_REG = (UDC_TXDMA_CFG_REG & ~mask) | UDC_DMA_REQ;

		if (req) {
			finish_in_dma(ep, req, -ECONNRESET);

			/* clear FIFO; hosts probably won't empty it */
			use_ep(ep, UDC_EP_SEL);
			UDC_CTRL_REG = UDC_CLR_EP;
			deselect_ep();
		}
		while (UDC_TXDMA_CFG_REG & mask)
			udelay(10);
	} else {
		UDC_RXDMA_CFG_REG = (UDC_RXDMA_CFG_REG & ~mask) | UDC_DMA_REQ;

		/* dma empties the fifo */
		while (UDC_RXDMA_CFG_REG & mask)
			udelay(10);
		if (req)
			finish_out_dma(ep, req, -ECONNRESET);
	}
	omap_free_dma(ep->lch);
	ep->dma_channel = 0;
	ep->lch = -1;
	/* has_dma still set, till endpoint is fully quiesced */
}


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

static int
omap_ep_queue(struct usb_ep *_ep, struct usb_request *_req, unsigned gfp_flags)
{
	struct omap_ep	*ep = container_of(_ep, struct omap_ep, ep);
	struct omap_req	*req = container_of(_req, struct omap_req, req);
	struct omap_udc	*udc;
	unsigned long	flags;
	int		is_iso = 0;

	/* catch various bogus parameters */
	if (!_req || !req->req.complete || !req->req.buf
			|| !list_empty(&req->queue)) {
		DBG("%s, bad params\n", __FUNCTION__);
		return -EINVAL;
	}
	if (!_ep || (!ep->desc && ep->bEndpointAddress)) {
		DBG("%s, bad ep\n", __FUNCTION__);
		return -EINVAL;
	}
	if (ep->bmAttributes == USB_ENDPOINT_XFER_ISOC) {
		if (req->req.length > ep->ep.maxpacket)
			return -EMSGSIZE;
		is_iso = 1;
	}

	/* this isn't bogus, but OMAP DMA isn't the only hardware to
	 * have a hard time with partial packet reads...  reject it.
	 */
	if (use_dma
			&& ep->has_dma
			&& ep->bEndpointAddress != 0
			&& (ep->bEndpointAddress & USB_DIR_IN) == 0
			&& (req->req.length % ep->ep.maxpacket) != 0) {
		DBG("%s, no partial packet OUT reads\n", __FUNCTION__);