pxa2xx_udc.c

linux下面gadget设备驱动

/*
 * linux/drivers/usb/gadget/pxa2xx_udc.c
 * Intel PXA25x and IXP4xx on-chip full speed USB device controllers
 *
 * Copyright (C) 2002 Intrinsyc, Inc. (Frank Becker)
 * Copyright (C) 2003 Robert Schwebel, Pengutronix
 * Copyright (C) 2003 Benedikt Spranger, Pengutronix
 * Copyright (C) 2003 David Brownell
 * Copyright (C) 2003 Joshua Wise
 *
 * 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
 *
 */

// #define	VERBOSE	DBG_VERBOSE

#include <linux/device.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/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/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/irq.h>
#include <linux/clk.h>
#include <linux/err.h>

#include <asm/byteorder.h>
#include <asm/dma.h>
#include <asm/gpio.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/mach-types.h>
#include <asm/unaligned.h>
#include <asm/hardware.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

#include <asm/mach/udc_pxa2xx.h>


/*
 * This driver handles the USB Device Controller (UDC) in Intel's PXA 25x
 * series processors.  The UDC for the IXP 4xx series is very similar.
 * There are fifteen endpoints, in addition to ep0.
 *
 * Such controller drivers work with a gadget driver.  The gadget driver
 * returns descriptors, implements configuration and data protocols used
 * by the host to interact with this device, and allocates endpoints to
 * the different protocol interfaces.  The controller driver virtualizes
 * usb hardware so that the gadget drivers will be more portable.
 *
 * This UDC hardware wants to implement a bit too much USB protocol, so
 * it constrains the sorts of USB configuration change events that work.
 * The errata for these chips are misleading; some "fixed" bugs from
 * pxa250 a0/a1 b0/b1/b2 sure act like they're still there.
 *
 * Note that the UDC hardware supports DMA (except on IXP) but that's
 * not used here.  IN-DMA (to host) is simple enough, when the data is
 * suitably aligned (16 bytes) ... the network stack doesn't do that,
 * other software can.  OUT-DMA is buggy in most chip versions, as well
 * as poorly designed (data toggle not automatic).  So this driver won't
 * bother using DMA.  (Mostly-working IN-DMA support was available in
 * kernels before 2.6.23, but was never enabled or well tested.)
 */

#define	DRIVER_VERSION	"30-June-2007"
#define	DRIVER_DESC	"PXA 25x USB Device Controller driver"


static const char driver_name [] = "pxa2xx_udc";

static const char ep0name [] = "ep0";


#ifdef CONFIG_ARCH_IXP4XX

/* cpu-specific register addresses are compiled in to this code */
#ifdef CONFIG_ARCH_PXA
#error "Can't configure both IXP and PXA"
#endif

#endif

#include "pxa2xx_udc.h"


#ifdef	CONFIG_USB_PXA2XX_SMALL
#define SIZE_STR	" (small)"
#else
#define SIZE_STR	""
#endif

/* ---------------------------------------------------------------------------
 *	endpoint related parts of the api to the usb controller hardware,
 *	used by gadget driver; and the inner talker-to-hardware core.
 * ---------------------------------------------------------------------------
 */

static void pxa2xx_ep_fifo_flush (struct usb_ep *ep);
static void nuke (struct pxa2xx_ep *, int status);

/* one GPIO should be used to detect VBUS from the host */
static int is_vbus_present(void)
{
	struct pxa2xx_udc_mach_info		*mach = the_controller->mach;

	if (mach->gpio_vbus)
		return gpio_get_value(mach->gpio_vbus);
	if (mach->udc_is_connected)
		return mach->udc_is_connected();
	return 1;
}

/* one GPIO should control a D+ pullup, so host sees this device (or not) */
static void pullup_off(void)
{
	struct pxa2xx_udc_mach_info		*mach = the_controller->mach;

	if (mach->gpio_pullup)
		gpio_set_value(mach->gpio_pullup, 0);
	else if (mach->udc_command)
		mach->udc_command(PXA2XX_UDC_CMD_DISCONNECT);
}

static void pullup_on(void)
{
	struct pxa2xx_udc_mach_info		*mach = the_controller->mach;

	if (mach->gpio_pullup)
		gpio_set_value(mach->gpio_pullup, 1);
	else if (mach->udc_command)
		mach->udc_command(PXA2XX_UDC_CMD_CONNECT);
}

static void pio_irq_enable(int bEndpointAddress)
{
        bEndpointAddress &= 0xf;
        if (bEndpointAddress < 8)
                UICR0 &= ~(1 << bEndpointAddress);
        else {
                bEndpointAddress -= 8;
                UICR1 &= ~(1 << bEndpointAddress);
	}
}

static void pio_irq_disable(int bEndpointAddress)
{
        bEndpointAddress &= 0xf;
        if (bEndpointAddress < 8)
                UICR0 |= 1 << bEndpointAddress;
        else {
                bEndpointAddress -= 8;
                UICR1 |= 1 << bEndpointAddress;
        }
}

/* The UDCCR reg contains mask and interrupt status bits,
 * so using '|=' isn't safe as it may ack an interrupt.
 */
#define UDCCR_MASK_BITS         (UDCCR_REM | UDCCR_SRM | UDCCR_UDE)

static inline void udc_set_mask_UDCCR(int mask)
{
	UDCCR = (UDCCR & UDCCR_MASK_BITS) | (mask & UDCCR_MASK_BITS);
}

static inline void udc_clear_mask_UDCCR(int mask)
{
	UDCCR = (UDCCR & UDCCR_MASK_BITS) & ~(mask & UDCCR_MASK_BITS);
}

static inline void udc_ack_int_UDCCR(int mask)
{
	/* udccr contains the bits we dont want to change */
	__u32 udccr = UDCCR & UDCCR_MASK_BITS;

	UDCCR = udccr | (mask & ~UDCCR_MASK_BITS);
}

/*
 * endpoint enable/disable
 *
 * we need to verify the descriptors used to enable endpoints.  since pxa2xx
 * endpoint configurations are fixed, and are pretty much always enabled,
 * there's not a lot to manage here.
 *
 * because pxa2xx can't selectively initialize bulk (or interrupt) endpoints,
 * (resetting endpoint halt and toggle), SET_INTERFACE is unusable except
 * for a single interface (with only the default altsetting) and for gadget
 * drivers that don't halt endpoints (not reset by set_interface).  that also
 * means that if you use ISO, you must violate the USB spec rule that all
 * iso endpoints must be in non-default altsettings.
 */
static int pxa2xx_ep_enable (struct usb_ep *_ep,
		const struct usb_endpoint_descriptor *desc)
{
	struct pxa2xx_ep        *ep;
	struct pxa2xx_udc       *dev;

	ep = container_of (_ep, struct pxa2xx_ep, ep);
	if (!_ep || !desc || ep->desc || _ep->name == ep0name
			|| desc->bDescriptorType != USB_DT_ENDPOINT
			|| ep->bEndpointAddress != desc->bEndpointAddress
			|| ep->fifo_size < le16_to_cpu
						(desc->wMaxPacketSize)) {
		DMSG("%s, bad ep or descriptor\n", __FUNCTION__);
		return -EINVAL;
	}

	/* 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) {
		DMSG("%s, %s type mismatch\n", __FUNCTION__, _ep->name);
		return -EINVAL;
	}

	/* hardware _could_ do smaller, but driver doesn't */
	if ((desc->bmAttributes == USB_ENDPOINT_XFER_BULK
				&& le16_to_cpu (desc->wMaxPacketSize)
						!= BULK_FIFO_SIZE)
			|| !desc->wMaxPacketSize) {
		DMSG("%s, bad %s maxpacket\n", __FUNCTION__, _ep->name);
		return -ERANGE;
	}

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

	ep->desc = desc;
	ep->stopped = 0;
	ep->pio_irqs = 0;
	ep->ep.maxpacket = le16_to_cpu (desc->wMaxPacketSize);

	/* flush fifo (mostly for OUT buffers) */
	pxa2xx_ep_fifo_flush (_ep);

	/* ... reset halt state too, if we could ... */

	DBG(DBG_VERBOSE, "enabled %s\n", _ep->name);
	return 0;
}

static int pxa2xx_ep_disable (struct usb_ep *_ep)
{
	struct pxa2xx_ep	*ep;
	unsigned long		flags;

	ep = container_of (_ep, struct pxa2xx_ep, ep);
	if (!_ep || !ep->desc) {
		DMSG("%s, %s not enabled\n", __FUNCTION__,
			_ep ? ep->ep.name : NULL);
		return -EINVAL;
	}
	local_irq_save(flags);

	nuke (ep, -ESHUTDOWN);

	/* flush fifo (mostly for IN buffers) */
	pxa2xx_ep_fifo_flush (_ep);

	ep->desc = NULL;
	ep->stopped = 1;

	local_irq_restore(flags);
	DBG(DBG_VERBOSE, "%s disabled\n", _ep->name);
	return 0;
}

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

/* for the pxa2xx, these can just wrap kmalloc/kfree.  gadget drivers
 * must still pass correctly initialized endpoints, since other controller
 * drivers may care about how it's currently set up (dma issues etc).
 */

/*
 *	pxa2xx_ep_alloc_request - allocate a request data structure
 */
static struct usb_request *
pxa2xx_ep_alloc_request (struct usb_ep *_ep, gfp_t gfp_flags)
{
	struct pxa2xx_request *req;

	req = kzalloc(sizeof(*req), gfp_flags);
	if (!req)
		return NULL;

	INIT_LIST_HEAD (&req->queue);
	return &req->req;
}


/*
 *	pxa2xx_ep_free_request - deallocate a request data structure
 */
static void
pxa2xx_ep_free_request (struct usb_ep *_ep, struct usb_request *_req)
{
	struct pxa2xx_request	*req;

	req = container_of (_req, struct pxa2xx_request, req);
	WARN_ON (!list_empty (&req->queue));
	kfree(req);
}

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

/*
 *	done - retire a request; caller blocked irqs
 */
static void done(struct pxa2xx_ep *ep, struct pxa2xx_request *req, int status)
{
	unsigned		stopped = ep->stopped;

	list_del_init(&req->queue);

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

	if (status && status != -ESHUTDOWN)
		DBG(DBG_VERBOSE, "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;
	req->req.complete(&ep->ep, &req->req);
	ep->stopped = stopped;
}


static inline void ep0_idle (struct pxa2xx_udc *dev)
{
	dev->ep0state = EP0_IDLE;
}

static int
write_packet(volatile u32 *uddr, struct pxa2xx_request *req, unsigned max)
{
	u8		*buf;
	unsigned	length, count;

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

	/* how big will this packet be? */
	length = min(req->req.length - req->req.actual, max);
	req->req.actual += length;

	count = length;
	while (likely(count--))
		*uddr = *buf++;

	return length;
}

/*
 * write to an IN endpoint fifo, as many packets as possible.
 * irqs will use this to write the rest later.
 * caller guarantees at least one packet buffer is ready (or a zlp).
 */
static int
write_fifo (struct pxa2xx_ep *ep, struct pxa2xx_request *req)
{
	unsigned		max;

	max = le16_to_cpu(ep->desc->wMaxPacketSize);
	do {
		unsigned	count;
		int		is_last, is_short;

		count = write_packet(ep->reg_uddr, req, max);

		/* last packet is usually short (or a zlp) */
		if (unlikely (count != max))
			is_last = is_short = 1;
		else {
			if (likely(req->req.length != req->req.actual)
					|| req->req.zero)
				is_last = 0;
			else
				is_last = 1;
			/* interrupt/iso maxpacket may not fill the fifo */
			is_short = unlikely (max < ep->fifo_size);
		}

		DBG(DBG_VERY_NOISY, "wrote %s %d bytes%s%s %d left %p\n",
			ep->ep.name, count,
			is_last ? "/L" : "", is_short ? "/S" : "",
			req->req.length - req->req.actual, req);

		/* let loose that packet. maybe try writing another one,
		 * double buffering might work.  TSP, TPC, and TFS
		 * bit values are the same for all normal IN endpoints.
		 */
		*ep->reg_udccs = UDCCS_BI_TPC;
		if (is_short)
			*ep->reg_udccs = UDCCS_BI_TSP;

		/* requests complete when all IN data is in the FIFO */
		if (is_last) {
			done (ep, req, 0);
			if (list_empty(&ep->queue))
				pio_irq_disable (ep->bEndpointAddress);
			return 1;
		}

		// TODO experiment: how robust can fifo mode tweaking be?
		// double buffering is off in the default fifo mode, which
		// prevents TFS from being set here.

	} while (*ep->reg_udccs & UDCCS_BI_TFS);
	return 0;
}

/* caller asserts req->pending (ep0 irq status nyet cleared); starts
 * ep0 data stage.  these chips want very simple state transitions.
 */
static inline
void ep0start(struct pxa2xx_udc *dev, u32 flags, const char *tag)
{
	UDCCS0 = flags|UDCCS0_SA|UDCCS0_OPR;
	USIR0 = USIR0_IR0;
	dev->req_pending = 0;
	DBG(DBG_VERY_NOISY, "%s %s, %02x/%02x\n",
		__FUNCTION__, tag, UDCCS0, flags);
}

static int
write_ep0_fifo (struct pxa2xx_ep *ep, struct pxa2xx_request *req)
{
	unsigned	count;
	int		is_short;

	count = write_packet(&UDDR0, req, EP0_FIFO_SIZE);
	ep->dev->stats.write.bytes += count;

	/* last packet "must be" short (or a zlp) */
	is_short = (count != EP0_FIFO_SIZE);

	DBG(DBG_VERY_NOISY, "ep0in %d bytes %d left %p\n", count,
		req->req.length - req->req.actual, req);

	if (unlikely (is_short)) {
		if (ep->dev->req_pending)
			ep0start(ep->dev, UDCCS0_IPR, "short IN");
		else
			UDCCS0 = UDCCS0_IPR;

		count = req->req.length;
		done (ep, req, 0);
		ep0_idle(ep->dev);
#ifndef CONFIG_ARCH_IXP4XX
#if 1
		/* This seems to get rid of lost status irqs in some cases:
		 * host responds quickly, or next request involves config
		 * change automagic, or should have been hidden, or ...
		 *
		 * FIXME get rid of all udelays possible...
		 */
		if (count >= EP0_FIFO_SIZE) {
			count = 100;
			do {
				if ((UDCCS0 & UDCCS0_OPR) != 0) {
					/* clear OPR, generate ack */
					UDCCS0 = UDCCS0_OPR;
					break;
				}
				count--;
				udelay(1);
			} while (count);
		}
#endif
#endif
	} else if (ep->dev->req_pending)
		ep0start(ep->dev, 0, "IN");
	return is_short;
}


/*
 * read_fifo -  unload packet(s) from the fifo we use for usb OUT
 * transfers and put them into the request.  caller should have made
 * sure there's at least one packet ready.
 *
 * returns true if the request completed because of short packet or the
 * request buffer having filled (and maybe overran till end-of-packet).
 */
static int
read_fifo (struct pxa2xx_ep *ep, struct pxa2xx_request *req)
{
	for (;;) {
		u32		udccs;
		u8		*buf;
		unsigned	bufferspace, count, is_short;

		/* make sure there's a packet in the FIFO.
		 * UDCCS_{BO,IO}_RPC are all the same bit value.
		 * UDCCS_{BO,IO}_RNE are all the same bit value.
		 */
		udccs = *ep->reg_udccs;
		if (unlikely ((udccs & UDCCS_BO_RPC) == 0))
			break;
		buf = req->req.buf + req->req.actual;
		prefetchw(buf);
		bufferspace = req->req.length - req->req.actual;

		/* read all bytes from this packet */
		if (likely (udccs & UDCCS_BO_RNE)) {
			count = 1 + (0x0ff & *ep->reg_ubcr);
			req->req.actual += min (count, bufferspace);
		} else /* zlp */
			count = 0;
		is_short = (count < ep->ep.maxpacket);
		DBG(DBG_VERY_NOISY, "read %s %02x, %d bytes%s req %p %d/%d\n",
			ep->ep.name, udccs, count,
			is_short ? "/S" : "",
			req, req->req.actual, req->req.length);
		while (likely (count-- != 0)) {
			u8	byte = (u8) *ep->reg_uddr;

			if (unlikely (bufferspace == 0)) {
				/* this happens when the driver's buffer
				 * is smaller than what the host sent.
				 * discard the extra data.
				 */
				if (req->req.status != -EOVERFLOW)
					DMSG("%s overflow %d\n",
						ep->ep.name, count);
				req->req.status = -EOVERFLOW;
			} else {
				*buf++ = byte;
				bufferspace--;
			}
		}
		*ep->reg_udccs =  UDCCS_BO_RPC;
		/* RPC/RSP/RNE could now reflect the other packet buffer */

		/* iso is one request per packet */
		if (ep->bmAttributes == USB_ENDPOINT_XFER_ISOC) {
			if (udccs & UDCCS_IO_ROF)
				req->req.status = -EHOSTUNREACH;
			/* more like "is_done" */
			is_short = 1;
		}

		/* completion */
		if (is_short || req->req.actual == req->req.length) {
			done (ep, req, 0);
			if (list_empty(&ep->queue))
				pio_irq_disable (ep->bEndpointAddress);
			return 1;
		}

		/* finished that packet.  the next one may be waiting... */
	}
	return 0;
}

/*
 * special ep0 version of the above.  no UBCR0 or double buffering; status
 * handshaking is magic.  most device protocols don't need control-OUT.
 * CDC vendor commands (and RNDIS), mass storage CB/CBI, and some other
 * protocols do use them.
 */
static int