omap_udc.c

ARM S3C2410 USB SLAVE LINUX驱动

/*
 * omap_udc.c -- for OMAP full speed udc; most chips support OTG.
 *
 * Copyright (C) 2004 Texas Instruments, Inc.
 * Copyright (C) 2004-2005 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#undef	DEBUG
#undef	VERBOSE

#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include <linux/mm.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/usb_ch9.h>
#include <linux/usb_gadget.h>
#include <linux/usb_otg.h>
#include <linux/dma-mapping.h>

#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/unaligned.h>
#include <asm/mach-types.h>

#include <asm/arch/dma.h>
#include <asm/arch/usb.h>

#include "omap_udc.h"

#undef	USB_TRACE

/* bulk DMA seems to be behaving for both IN and OUT */
#define	USE_DMA

/* ISO too */
#define	USE_ISO

#define	DRIVER_DESC	"OMAP UDC driver"
#define	DRIVER_VERSION	"4 October 2004"

#define	DMA_ADDR_INVALID	(~(dma_addr_t)0)


/*
 * The OMAP UDC needs _very_ early endpoint setup:  before enabling the
 * D+ pullup to allow enumeration.  That's too early for the gadget
 * framework to use from usb_endpoint_enable(), which happens after
 * enumeration as part of activating an interface.  (But if we add an
 * optional new "UDC not yet running" state to the gadget driver model,
 * even just during driver binding, the endpoint autoconfig logic is the
 * natural spot to manufacture new endpoints.)
 *
 * So instead of using endpoint enable calls to control the hardware setup,
 * this driver defines a "fifo mode" parameter.  It's used during driver
 * initialization to choose among a set of pre-defined endpoint configs.
 * See omap_udc_setup() for available modes, or to add others.  That code
 * lives in an init section, so use this driver as a module if you need
 * to change the fifo mode after the kernel boots.
 *
 * Gadget drivers normally ignore endpoints they don't care about, and
 * won't include them in configuration descriptors.  That means only
 * misbehaving hosts would even notice they exist.
 */
#ifdef	USE_ISO
static unsigned fifo_mode = 3;
#else
static unsigned fifo_mode = 0;
#endif

/* "modprobe omap_udc fifo_mode=42", or else as a kernel
 * boot parameter "omap_udc:fifo_mode=42"
 */
module_param (fifo_mode, uint, 0);
MODULE_PARM_DESC (fifo_mode, "endpoint setup (0 == default)");

#ifdef	USE_DMA
static unsigned use_dma = 1;

/* "modprobe omap_udc use_dma=y", or else as a kernel
 * boot parameter "omap_udc:use_dma=y"
 */
module_param (use_dma, bool, 0);
MODULE_PARM_DESC (use_dma, "enable/disable DMA");
#else	/* !USE_DMA */

/* save a bit of code */
#define	use_dma		0
#endif	/* !USE_DMA */


static const char driver_name [] = "omap_udc";
static const char driver_desc [] = DRIVER_DESC;

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

/* there's a notion of "current endpoint" for modifying endpoint
 * state, and PIO access to its FIFO.  
 */

static void use_ep(struct omap_ep *ep, u16 select)
{
	u16	num = ep->bEndpointAddress & 0x0f;

	if (ep->bEndpointAddress & USB_DIR_IN)
		num |= UDC_EP_DIR;
	UDC_EP_NUM_REG = num | select;
	/* when select, MUST deselect later !! */
}

static inline void deselect_ep(void)
{
	UDC_EP_NUM_REG &= ~UDC_EP_SEL;
	/* 6 wait states before TX will happen */
}

static void dma_channel_claim(struct omap_ep *ep, unsigned preferred);

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

static int omap_ep_enable(struct usb_ep *_ep,
		const struct usb_endpoint_descriptor *desc)
{
	struct omap_ep	*ep = container_of(_ep, struct omap_ep, ep);
	struct omap_udc	*udc;
	unsigned long	flags;
	u16		maxp;

	/* catch various bogus parameters */
	if (!_ep || !desc || ep->desc
			|| desc->bDescriptorType != USB_DT_ENDPOINT
			|| ep->bEndpointAddress != desc->bEndpointAddress
			|| ep->maxpacket < le16_to_cpu
						(desc->wMaxPacketSize)) {
		DBG("%s, bad ep or descriptor\n", __FUNCTION__);
		return -EINVAL;
	}
	maxp = le16_to_cpu (desc->wMaxPacketSize);
	if ((desc->bmAttributes == USB_ENDPOINT_XFER_BULK
				&& maxp != ep->maxpacket)
			|| le16_to_cpu(desc->wMaxPacketSize) > ep->maxpacket
			|| !desc->wMaxPacketSize) {
		DBG("%s, bad %s maxpacket\n", __FUNCTION__, _ep->name);
		return -ERANGE;
	}

#ifdef	USE_ISO
	if ((desc->bmAttributes == USB_ENDPOINT_XFER_ISOC
				&& desc->bInterval != 1)) {
		/* hardware wants period = 1; USB allows 2^(Interval-1) */
		DBG("%s, unsupported ISO period %dms\n", _ep->name,
				1 << (desc->bInterval - 1));
		return -EDOM;
	}
#else
	if (desc->bmAttributes == USB_ENDPOINT_XFER_ISOC) {
		DBG("%s, ISO nyet\n", _ep->name);
		return -EDOM;
	}
#endif

	/* xfer types must match, except that interrupt ~= bulk */
	if (ep->bmAttributes != desc->bmAttributes
			&& ep->bmAttributes != USB_ENDPOINT_XFER_BULK
			&& desc->bmAttributes != USB_ENDPOINT_XFER_INT) {
		DBG("%s, %s type mismatch\n", __FUNCTION__, _ep->name);
		return -EINVAL;
	}

	udc = ep->udc;
	if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN) {
		DBG("%s, bogus device state\n", __FUNCTION__);
		return -ESHUTDOWN;
	}

	spin_lock_irqsave(&udc->lock, flags);

	ep->desc = desc;
	ep->irqs = 0;
	ep->stopped = 0;
	ep->ep.maxpacket = maxp;

	/* set endpoint to initial state */
	ep->dma_channel = 0;
	ep->has_dma = 0;
	ep->lch = -1;
	use_ep(ep, UDC_EP_SEL);
	UDC_CTRL_REG = udc->clr_halt;
	ep->ackwait = 0;
	deselect_ep();

	if (ep->bmAttributes == USB_ENDPOINT_XFER_ISOC)
		list_add(&ep->iso, &udc->iso);

	/* maybe assign a DMA channel to this endpoint */
	if (use_dma && desc->bmAttributes == USB_ENDPOINT_XFER_BULK)
		/* FIXME ISO can dma, but prefers first channel */
		dma_channel_claim(ep, 0);

	/* PIO OUT may RX packets */
	if (desc->bmAttributes != USB_ENDPOINT_XFER_ISOC
			&& !ep->has_dma
			&& !(ep->bEndpointAddress & USB_DIR_IN)) {
		UDC_CTRL_REG = UDC_SET_FIFO_EN;
		ep->ackwait = 1 + ep->double_buf;
	}

	spin_unlock_irqrestore(&udc->lock, flags);
	VDBG("%s enabled\n", _ep->name);
	return 0;
}

static void nuke(struct omap_ep *, int status);

static int omap_ep_disable(struct usb_ep *_ep)
{
	struct omap_ep	*ep = container_of(_ep, struct omap_ep, ep);
	unsigned long	flags;

	if (!_ep || !ep->desc) {
		DBG("%s, %s not enabled\n", __FUNCTION__,
			_ep ? ep->ep.name : NULL);
		return -EINVAL;
	}

	spin_lock_irqsave(&ep->udc->lock, flags);
	ep->desc = NULL;
	nuke (ep, -ESHUTDOWN);
	ep->ep.maxpacket = ep->maxpacket;
	ep->has_dma = 0;
	UDC_CTRL_REG = UDC_SET_HALT;
	list_del_init(&ep->iso);
	del_timer(&ep->timer);

	spin_unlock_irqrestore(&ep->udc->lock, flags);

	VDBG("%s disabled\n", _ep->name);
	return 0;
}

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

static struct usb_request *
omap_alloc_request(struct usb_ep *ep, unsigned gfp_flags)
{
	struct omap_req	*req;

	req = kmalloc(sizeof *req, gfp_flags);
	if (req) {
		memset (req, 0, sizeof *req);
		req->req.dma = DMA_ADDR_INVALID;
		INIT_LIST_HEAD (&req->queue);
	}
	return &req->req;
}

static void
omap_free_request(struct usb_ep *ep, struct usb_request *_req)
{
	struct omap_req	*req = container_of(_req, struct omap_req, req);

	if (_req)
		kfree (req);
}

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

static void *
omap_alloc_buffer(
	struct usb_ep	*_ep,
	unsigned	bytes,
	dma_addr_t	*dma,
	unsigned	gfp_flags
)
{
	void		*retval;
	struct omap_ep	*ep;

	ep = container_of(_ep, struct omap_ep, ep);
	if (use_dma && ep->has_dma) {
		static int	warned;
		if (!warned && bytes < PAGE_SIZE) {
			dev_warn(ep->udc->gadget.dev.parent,
				"using dma_alloc_coherent for "
				"small allocations wastes memory\n");
			warned++;
		}
		return dma_alloc_coherent(ep->udc->gadget.dev.parent,
				bytes, dma, gfp_flags);
	}

	retval = kmalloc(bytes, gfp_flags);
	if (retval)
		*dma = virt_to_phys(retval);
	return retval;
}

static void omap_free_buffer(
	struct usb_ep	*_ep,
	void		*buf,
	dma_addr_t	dma,
	unsigned	bytes
)
{
	struct omap_ep	*ep;

	ep = container_of(_ep, struct omap_ep, ep);
	if (use_dma && _ep && ep->has_dma)
		dma_free_coherent(ep->udc->gadget.dev.parent, bytes, buf, dma);
	else
		kfree (buf);
}

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

static void
done(struct omap_ep *ep, struct omap_req *req, int status)
{
	unsigned		stopped = ep->stopped;

	list_del_init(&req->queue);

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

	if (use_dma && ep->has_dma) {
		if (req->mapped) {
			dma_unmap_single(ep->udc->gadget.dev.parent,
				req->req.dma, req->req.length,
				(ep->bEndpointAddress & USB_DIR_IN)
					? DMA_TO_DEVICE
					: DMA_FROM_DEVICE);
			req->req.dma = DMA_ADDR_INVALID;
			req->mapped = 0;
		} else
			dma_sync_single_for_cpu(ep->udc->gadget.dev.parent,
				req->req.dma, req->req.length,
				(ep->bEndpointAddress & USB_DIR_IN)
					? DMA_TO_DEVICE
					: DMA_FROM_DEVICE);
	}

#ifndef	USB_TRACE
	if (status && status != -ESHUTDOWN)
#endif
		VDBG("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(&ep->udc->lock);
	req->req.complete(&ep->ep, &req->req);
	spin_lock(&ep->udc->lock);
	ep->stopped = stopped;
}

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

#define UDC_FIFO_FULL		(UDC_NON_ISO_FIFO_FULL | UDC_ISO_FIFO_FULL)
#define UDC_FIFO_UNWRITABLE	(UDC_EP_HALTED | UDC_FIFO_FULL)

#define FIFO_EMPTY	(UDC_NON_ISO_FIFO_EMPTY | UDC_ISO_FIFO_EMPTY)
#define FIFO_UNREADABLE (UDC_EP_HALTED | FIFO_EMPTY)

static inline int 
write_packet(u8 *buf, struct omap_req *req, unsigned max)
{
	unsigned	len;
	u16		*wp;

	len = min(req->req.length - req->req.actual, max);
	req->req.actual += len;

	max = len;
	if (likely((((int)buf) & 1) == 0)) {
		wp = (u16 *)buf;
		while (max >= 2) {
			UDC_DATA_REG = *wp++;
			max -= 2;
		}
		buf = (u8 *)wp;
	}
	while (max--)
		*(volatile u8 *)&UDC_DATA_REG = *buf++;
	return len;
}

// FIXME change r/w fifo calling convention


// return:  0 = still running, 1 = completed, negative = errno
static int write_fifo(struct omap_ep *ep, struct omap_req *req)
{
	u8		*buf;
	unsigned	count;
	int		is_last;
	u16		ep_stat;

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

	/* PIO-IN isn't double buffered except for iso */
	ep_stat = UDC_STAT_FLG_REG;
	if (ep_stat & UDC_FIFO_UNWRITABLE)
		return 0;

	count = ep->ep.maxpacket;
	count = write_packet(buf, req, count);
	UDC_CTRL_REG = UDC_SET_FIFO_EN;
	ep->ackwait = 1;

	/* last packet is often short (sometimes a zlp) */
	if (count != ep->ep.maxpacket)
		is_last = 1;
	else if (req->req.length == req->req.actual
			&& !req->req.zero)
		is_last = 1;
	else
		is_last = 0;

	/* NOTE:  requests complete when all IN data is in a
	 * FIFO (or sometimes later, if a zlp was needed).
	 * Use usb_ep_fifo_status() where needed.
	 */
	if (is_last)
		done(ep, req, 0);
	return is_last;
}

static inline int 
read_packet(u8 *buf, struct omap_req *req, unsigned avail)
{
	unsigned	len;
	u16		*wp;

	len = min(req->req.length - req->req.actual, avail);
	req->req.actual += len;
	avail = len;

	if (likely((((int)buf) & 1) == 0)) {
		wp = (u16 *)buf;
		while (avail >= 2) {
			*wp++ = UDC_DATA_REG;
			avail -= 2;
		}
		buf = (u8 *)wp;
	}
	while (avail--)
		*buf++ = *(volatile u8 *)&UDC_DATA_REG;
	return len;
}

// return:  0 = still running, 1 = queue empty, negative = errno
static int read_fifo(struct omap_ep *ep, struct omap_req *req)
{