drivers/usb/wusbcore/wa-xfer.c



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/*
 * WUSB Wire Adapter
 * Data transfer and URB enqueing
 *
 * Copyright (C) 2005-2006 Intel Corporation
 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 *
 * How transfers work: get a buffer, break it up in segments (segment
 * size is a multiple of the maxpacket size). For each segment issue a
 * segment request (struct wa_xfer_*), then send the data buffer if
 * out or nothing if in (all over the DTO endpoint).
 *
 * For each submitted segment request, a notification will come over
 * the NEP endpoint and a transfer result (struct xfer_result) will
 * arrive in the DTI URB. Read it, get the xfer ID, see if there is
 * data coming (inbound transfer), schedule a read and handle it.
 *
 * Sounds simple, it is a pain to implement.
 *
 *
 * ENTRY POINTS
 *
 *   FIXME
 *
 * LIFE CYCLE / STATE DIAGRAM
 *
 *   FIXME
 *
 * THIS CODE IS DISGUSTING
 *
 *   Warned you are; it's my second try and still not happy with it.
 *
 * NOTES:
 *
 *   - No iso
 *
 *   - Supports DMA xfers, control, bulk and maybe interrupt
 *
 *   - Does not recycle unused rpipes
 *
 *     An rpipe is assigned to an endpoint the first time it is used,
 *     and then it's there, assigned, until the endpoint is disabled
 *     (destroyed [{h,d}wahc_op_ep_disable()]. The assignment of the
 *     rpipe to the endpoint is done under the wa->rpipe_sem semaphore
 *     (should be a mutex).
 *
 *     Two methods it could be done:
 *
 *     (a) set up a timer every time an rpipe's use count drops to 1
 *         (which means unused) or when a transfer ends. Reset the
 *         timer when a xfer is queued. If the timer expires, release
 *         the rpipe [see rpipe_ep_disable()].
 *
 *     (b) when looking for free rpipes to attach [rpipe_get_by_ep()],
 *         when none are found go over the list, check their endpoint
 *         and their activity record (if no last-xfer-done-ts in the
 *         last x seconds) take it
 *
 *     However, due to the fact that we have a set of limited
 *     resources (max-segments-at-the-same-time per xfer,
 *     xfers-per-ripe, blocks-per-rpipe, rpipes-per-host), at the end
 *     we are going to have to rebuild all this based on an scheduler,
 *     to where we have a list of transactions to do and based on the
 *     availability of the different required components (blocks,
 *     rpipes, segment slots, etc), we go scheduling them. Painful.
 */
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/hash.h>
#include <linux/ratelimit.h>
#include <linux/export.h>

#include "wa-hc.h"
#include "wusbhc.h"

enum {
	WA_SEGS_MAX = 255,
};

enum wa_seg_status {
	WA_SEG_NOTREADY,
	WA_SEG_READY,
	WA_SEG_DELAYED,
	WA_SEG_SUBMITTED,
	WA_SEG_PENDING,
	WA_SEG_DTI_PENDING,
	WA_SEG_DONE,
	WA_SEG_ERROR,
	WA_SEG_ABORTED,
};

static void wa_xfer_delayed_run(struct wa_rpipe *);

/*
 * Life cycle governed by 'struct urb' (the refcount of the struct is
 * that of the 'struct urb' and usb_free_urb() would free the whole
 * struct).
 */
struct wa_seg {
	struct urb urb;
	struct urb *dto_urb;		/* for data output? */
	struct list_head list_node;	/* for rpipe->req_list */
	struct wa_xfer *xfer;		/* out xfer */
	u8 index;			/* which segment we are */
	enum wa_seg_status status;
	ssize_t result;			/* bytes xfered or error */
	struct wa_xfer_hdr xfer_hdr;
	u8 xfer_extra[];		/* xtra space for xfer_hdr_ctl */
};

static void wa_seg_init(struct wa_seg *seg)
{
	/* usb_init_urb() repeats a lot of work, so we do it here */
	kref_init(&seg->urb.kref);
}

/*
 * Protected by xfer->lock
 *
 */
struct wa_xfer {
	struct kref refcnt;
	struct list_head list_node;
	spinlock_t lock;
	u32 id;

	struct wahc *wa;		/* Wire adapter we are plugged to */
	struct usb_host_endpoint *ep;
	struct urb *urb;		/* URB we are transferring for */
	struct wa_seg **seg;		/* transfer segments */
	u8 segs, segs_submitted, segs_done;
	unsigned is_inbound:1;
	unsigned is_dma:1;
	size_t seg_size;
	int result;

	gfp_t gfp;			/* allocation mask */

	struct wusb_dev *wusb_dev;	/* for activity timestamps */
};

static inline void wa_xfer_init(struct wa_xfer *xfer)
{
	kref_init(&xfer->refcnt);
	INIT_LIST_HEAD(&xfer->list_node);
	spin_lock_init(&xfer->lock);
}

/*
 * Destroy a transfer structure
 *
 * Note that the xfer->seg[index] thingies follow the URB life cycle,
 * so we need to put them, not free them.
 */
static void wa_xfer_destroy(struct kref *_xfer)
{
	struct wa_xfer *xfer = container_of(_xfer, struct wa_xfer, refcnt);
	if (xfer->seg) {
		unsigned cnt;
		for (cnt = 0; cnt < xfer->segs; cnt++) {
			if (xfer->is_inbound)
				usb_put_urb(xfer->seg[cnt]->dto_urb);
			usb_put_urb(&xfer->seg[cnt]->urb);
		}
	}
	kfree(xfer);
}

static void wa_xfer_get(struct wa_xfer *xfer)
{
	kref_get(&xfer->refcnt);
}

static void wa_xfer_put(struct wa_xfer *xfer)
{
	kref_put(&xfer->refcnt, wa_xfer_destroy);
}

/*
 * xfer is referenced
 *
 * xfer->lock has to be unlocked
 *
 * We take xfer->lock for setting the result; this is a barrier
 * against drivers/usb/core/hcd.c:unlink1() being called after we call
 * usb_hcd_giveback_urb() and wa_urb_dequeue() trying to get a
 * reference to the transfer.
 */
static void wa_xfer_giveback(struct wa_xfer *xfer)
{
	unsigned long flags;

	spin_lock_irqsave(&xfer->wa->xfer_list_lock, flags);
	list_del_init(&xfer->list_node);
	spin_unlock_irqrestore(&xfer->wa->xfer_list_lock, flags);
	/* FIXME: segmentation broken -- kills DWA */
	wusbhc_giveback_urb(xfer->wa->wusb, xfer->urb, xfer->result);
	wa_put(xfer->wa);
	wa_xfer_put(xfer);
}

/*
 * xfer is referenced
 *
 * xfer->lock has to be unlocked
 */
static void wa_xfer_completion(struct wa_xfer *xfer)
{
	if (xfer->wusb_dev)
		wusb_dev_put(xfer->wusb_dev);
	rpipe_put(xfer->ep->hcpriv);
	wa_xfer_giveback(xfer);
}

/*
 * If transfer is done, wrap it up and return true
 *
 * xfer->lock has to be locked
 */
static unsigned __wa_xfer_is_done(struct wa_xfer *xfer)
{
	struct device *dev = &xfer->wa->usb_iface->dev;
	unsigned result, cnt;
	struct wa_seg *seg;
	struct urb *urb = xfer->urb;
	unsigned found_short = 0;

	result = xfer->segs_done == xfer->segs_submitted;
	if (result == 0)
		goto out;
	urb->actual_length = 0;
	for (cnt = 0; cnt < xfer->segs; cnt++) {
		seg = xfer->seg[cnt];
		switch (seg->status) {
		case WA_SEG_DONE:
			if (found_short && seg->result > 0) {
				dev_dbg(dev, "xfer %p#%u: bad short segments (%zu)\n",
					xfer, cnt, seg->result);
				urb->status = -EINVAL;
				goto out;
			}
			urb->actual_length += seg->result;
			if (seg->result < xfer->seg_size
			    && cnt != xfer->segs-1)
				found_short = 1;
			dev_dbg(dev, "xfer %p#%u: DONE short %d "
				"result %zu urb->actual_length %d\n",
				xfer, seg->index, found_short, seg->result,
				urb->actual_length);
			break;
		case WA_SEG_ERROR:
			xfer->result = seg->result;
			dev_dbg(dev, "xfer %p#%u: ERROR result %zu\n",
				xfer, seg->index, seg->result);
			goto out;
		case WA_SEG_ABORTED:
			dev_dbg(dev, "xfer %p#%u ABORTED: result %d\n",
				xfer, seg->index, urb->status);
			xfer->result = urb->status;
			goto out;
		default:
			dev_warn(dev, "xfer %p#%u: is_done bad state %d\n",
				 xfer, cnt, seg->status);
			xfer->result = -EINVAL;
			goto out;
		}
	}
	xfer->result = 0;
out:
	return result;
}

/*
 * Initialize a transfer's ID
 *
 * We need to use a sequential number; if we use the pointer or the
 * hash of the pointer, it can repeat over sequential transfers and
 * then it will confuse the HWA....wonder why in hell they put a 32
 * bit handle in there then.
 */
static void wa_xfer_id_init(struct wa_xfer *xfer)
{
	xfer->id = atomic_add_return(1, &xfer->wa->xfer_id_count);
}

/*
 * Return the xfer's ID associated with xfer
 *
 * Need to generate a
 */
static u32 wa_xfer_id(struct wa_xfer *xfer)
{
	return xfer->id;
}

/*
 * Search for a transfer list ID on the HCD's URB list
 *
 * For 32 bit architectures, we use the pointer itself; for 64 bits, a
 * 32-bit hash of the pointer.
 *
 * @returns NULL if not found.
 */
static struct wa_xfer *wa_xfer_get_by_id(struct wahc *wa, u32 id)
{
	unsigned long flags;
	struct wa_xfer *xfer_itr;
	spin_lock_irqsave(&wa->xfer_list_lock, flags);
	list_for_each_entry(xfer_itr, &wa->xfer_list, list_node) {
		if (id == xfer_itr->id) {
			wa_xfer_get(xfer_itr);
			goto out;
		}
	}
	xfer_itr = NULL;
out:
	spin_unlock_irqrestore(&wa->xfer_list_lock, flags);
	return xfer_itr;
}

struct wa_xfer_abort_buffer {
	struct urb urb;
	struct wa_xfer_abort cmd;
};

static void __wa_xfer_abort_cb(struct urb *urb)
{
	struct wa_xfer_abort_buffer *b = urb->context;
	usb_put_urb(&b->urb);
}

/*
 * Aborts an ongoing transaction
 *
 * Assumes the transfer is referenced and locked and in a submitted
 * state (mainly that there is an endpoint/rpipe assigned).
 *
 * The callback (see above) does nothing but freeing up the data by
 * putting the URB. Because the URB is allocated at the head of the
 * struct, the whole space we allocated is kfreed.
 *
 * We'll get an 'aborted transaction' xfer result on DTI, that'll
 * politely ignore because at this point the transaction has been
 * marked as aborted already.
 */
static void __wa_xfer_abort(struct wa_xfer *xfer)
{
	int result;
	struct device *dev = &xfer->wa->usb_iface->dev;
	struct wa_xfer_abort_buffer *b;
	struct wa_rpipe *rpipe = xfer->ep->hcpriv;

	b = kmalloc(sizeof(*b), GFP_ATOMIC);
	if (b == NULL)
		goto error_kmalloc;
	b->cmd.bLength =  sizeof(b->cmd);
	b->cmd.bRequestType = WA_XFER_ABORT;
	b->cmd.wRPipe = rpipe->descr.wRPipeIndex;
	b->cmd.dwTransferID = wa_xfer_id(xfer);

	usb_init_urb(&b->urb);
	usb_fill_bulk_urb(&b->urb, xfer->wa->usb_dev,
		usb_sndbulkpipe(xfer->wa->usb_dev,
				xfer->wa->dto_epd->bEndpointAddress),
		&b->cmd, sizeof(b->cmd), __wa_xfer_abort_cb, b);
	result = usb_submit_urb(&b->urb, GFP_ATOMIC);
	if (result < 0)
		goto error_submit;
	return;				/* callback frees! */


error_submit:
	if (printk_ratelimit())
		dev_err(dev, "xfer %p: Can't submit abort request: %d\n",
			xfer, result);
	kfree(b);
error_kmalloc:
	return;

}

/*
 *
 * @returns < 0 on error, transfer segment request size if ok
 */
static ssize_t __wa_xfer_setup_sizes(struct wa_xfer *xfer,
				     enum wa_xfer_type *pxfer_type)
{
	ssize_t result;
	struct device *dev = &xfer->wa->usb_iface->dev;
	size_t maxpktsize;
	struct urb *urb = xfer->urb;
	struct wa_rpipe *rpipe = xfer->ep->hcpriv;

	switch (rpipe->descr.bmAttribute & 0x3) {
	case USB_ENDPOINT_XFER_CONTROL:
		*pxfer_type = WA_XFER_TYPE_CTL;
		result = sizeof(struct wa_xfer_ctl);
		break;
	case USB_ENDPOINT_XFER_INT:
	case USB_ENDPOINT_XFER_BULK:
		*pxfer_type = WA_XFER_TYPE_BI;
		result = sizeof(struct wa_xfer_bi);
		break;
	case USB_ENDPOINT_XFER_ISOC:
		dev_err(dev, "FIXME: ISOC not implemented\n");
		result = -ENOSYS;
		goto error;
	default:
		/* never happens */
		BUG();
		result = -EINVAL;	/* shut gcc up */
	};
	xfer->is_inbound = urb->pipe & USB_DIR_IN ? 1 : 0;
	xfer->is_dma = urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP ? 1 : 0;
	xfer->seg_size = le16_to_cpu(rpipe->descr.wBlocks)
		* 1 << (xfer->wa->wa_descr->bRPipeBlockSize - 1);
	/* Compute the segment size and make sure it is a multiple of
	 * the maxpktsize (WUSB1.0[8.3.3.1])...not really too much of
	 * a check (FIXME) */
	maxpktsize = le16_to_cpu(rpipe->descr.wMaxPacketSize);
	if (xfer->seg_size < maxpktsize) {
		dev_err(dev, "HW BUG? seg_size %zu smaller than maxpktsize "
			"%zu\n", xfer->seg_size, maxpktsize);
		result = -EINVAL;
		goto error;
	}
	xfer->seg_size = (xfer->seg_size / maxpktsize) * maxpktsize;
	xfer->segs = (urb->transfer_buffer_length + xfer->seg_size - 1)
		/ xfer->seg_size;
	if (xfer->segs >= WA_SEGS_MAX) {
		dev_err(dev, "BUG? ops, number of segments %d bigger than %d\n",
			(int)(urb->transfer_buffer_length / xfer->seg_size),
			WA_SEGS_MAX);
		result = -EINVAL;
		goto error;
	}
	if (xfer->segs == 0 && *pxfer_type == WA_XFER_TYPE_CTL)
		xfer->segs = 1;
error:
	return result;
}

/* Fill in the common request header and xfer-type specific data. */
static void __wa_xfer_setup_hdr0(struct wa_xfer *xfer,
				 struct wa_xfer_hdr *xfer_hdr0,
				 enum wa_xfer_type xfer_type,
				 size_t xfer_hdr_size)
{
	struct wa_rpipe *rpipe = xfer->ep->hcpriv;

	xfer_hdr0 = &xfer->seg[0]->xfer_hdr;
	xfer_hdr0->bLength = xfer_hdr_size;
	xfer_hdr0->bRequestType = xfer_type;
	xfer_hdr0->wRPipe = rpipe->descr.wRPipeIndex;
	xfer_hdr0->dwTransferID = wa_xfer_id(xfer);
	xfer_hdr0->bTransferSegment = 0;
	switch (xfer_type) {
	case WA_XFER_TYPE_CTL: {
		struct wa_xfer_ctl *xfer_ctl =
			container_of(xfer_hdr0, struct wa_xfer_ctl, hdr);
		xfer_ctl->bmAttribute = xfer->is_inbound ? 1 : 0;
		memcpy(&xfer_ctl->baSetupData, xfer->urb->setup_packet,
		       sizeof(xfer_ctl->baSetupData));
		break;
	}
	case WA_XFER_TYPE_BI:
		break;
	case WA_XFER_TYPE_ISO:
		printk(KERN_ERR "FIXME: ISOC not implemented\n");
	default:
		BUG();
	};
}

/*
 * Callback for the OUT data phase of the segment request
 *
 * Check wa_seg_cb(); most comments also apply here because this
 * function does almost the same thing and they work closely
 * together.
 *
 * If the seg request has failed but this DTO phase has succeeded,
 * wa_seg_cb() has already failed the segment and moved the
 * status to WA_SEG_ERROR, so this will go through 'case 0' and
 * effectively do nothing.
 */
static void wa_seg_dto_cb(struct urb *urb)
{
	struct wa_seg *seg = urb->context;
	struct wa_xfer *xfer = seg->xfer;
	struct wahc *wa;
	struct device *dev;
	struct wa_rpipe *rpipe;
	unsigned long flags;
	unsigned rpipe_ready = 0;
	u8 done = 0;

	switch (urb->status) {
	case 0:
		spin_lock_irqsave(&xfer->lock, flags);
		wa = xfer->wa;
		dev = &wa->usb_iface->dev;
		dev_dbg(dev, "xfer %p#%u: data out done (%d bytes)\n",
			xfer, seg->index, urb->actual_length);
		if (seg->status < WA_SEG_PENDING)
			seg->status = WA_SEG_PENDING;
		seg->result = urb->actual_length;
		spin_unlock_irqrestore(&xfer->lock, flags);
		break;
	case -ECONNRESET:	/* URB unlinked; no need to do anything */
	case -ENOENT:		/* as it was done by the who unlinked us */
		break;
	default:		/* Other errors ... */
		spin_lock_irqsave(&xfer->lock, flags);
		wa = xfer->wa;
		dev = &wa->usb_iface->dev;
		rpipe = xfer->ep->hcpriv;
		dev_dbg(dev, "xfer %p#%u: data out error %d\n",
			xfer, seg->index, urb->status);
		if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
			    EDC_ERROR_TIMEFRAME)){
			dev_err(dev, "DTO: URB max acceptable errors "
				"exceeded, resetting device\n");
			wa_reset_all(wa);
		}
		if (seg->status != WA_SEG_ERROR) {
			seg->status = WA_SEG_ERROR;
			seg->result = urb->status;
			xfer->segs_done++;
			__wa_xfer_abort(xfer);
			rpipe_ready = rpipe_avail_inc(rpipe);
			done = __wa_xfer_is_done(xfer);
		}
		spin_unlock_irqrestore(&xfer->lock, flags);
		if (done)
			wa_xfer_completion(xfer);
		if (rpipe_ready)
			wa_xfer_delayed_run(rpipe);
	}
}

/*
 * Callback for the segment request
 *
 * If successful transition state (unless already transitioned or
 * outbound transfer); otherwise, take a note of the error, mark this
 * segment done and try completion.
 *
 * Note we don't access until we are sure that the transfer hasn't
 * been cancelled (ECONNRESET, ENOENT), which could mean that
 * seg->xfer could be already gone.
 *
 * We have to check before setting the status to WA_SEG_PENDING
 * because sometimes the xfer result callback arrives before this
 * callback (geeeeeeze), so it might happen that we are already in
 * another state. As well, we don't set it if the transfer is inbound,
 * as in that case, wa_seg_dto_cb will do it when the OUT data phase
 * finishes.
 */
static void wa_seg_cb(struct urb *urb)
{
	struct wa_seg *seg = urb->context;
	struct wa_xfer *xfer = seg->xfer;
	struct wahc *wa;
	struct device *dev;
	struct wa_rpipe *rpipe;
	unsigned long flags;
	unsigned rpipe_ready;
	u8 done = 0;

	switch (urb->status) {
	case 0:
		spin_lock_irqsave(&xfer->lock, flags);
		wa = xfer->wa;