wusb: add the Wire Adapter (WA) core

Common code for supporting Host Wire Adapters and Device Wire Adapters.

Signed-off-by: David Vrabel <david.vrabel@csr.com>

1 files changed, 310 insertions, 0 deletions

diff --git a/drivers/usb/wusbcore/wa-nep.c b/drivers/usb/wusbcore/wa-nep.c
new file mode 100644
index 0000000..3f54299
--- /dev/null
+++ b/drivers/usb/wusbcore/wa-nep.c
@@ -0,0 +1,310 @@
+/*
+ * WUSB Wire Adapter: Control/Data Streaming Interface (WUSB[8])
+ * Notification EndPoint support
+ *
+ * Copyright (C) 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.
+ *
+ *
+ * This part takes care of getting the notification from the hw
+ * only and dispatching through wusbwad into
+ * wa_notif_dispatch. Handling is done there.
+ *
+ * WA notifications are limited in size; most of them are three or
+ * four bytes long, and the longest is the HWA Device Notification,
+ * which would not exceed 38 bytes (DNs are limited in payload to 32
+ * bytes plus 3 bytes header (WUSB1.0[7.6p2]), plus 3 bytes HWA
+ * header (WUSB1.0[8.5.4.2]).
+ *
+ * It is not clear if more than one Device Notification can be packed
+ * in a HWA Notification, I assume no because of the wording in
+ * WUSB1.0[8.5.4.2]. In any case, the bigger any notification could
+ * get is 256 bytes (as the bLength field is a byte).
+ *
+ * So what we do is we have this buffer and read into it; when a
+ * notification arrives we schedule work to a specific, single thread
+ * workqueue (so notifications are serialized) and copy the
+ * notification data. After scheduling the work, we rearm the read from
+ * the notification endpoint.
+ *
+ * Entry points here are:
+ *
+ * wa_nep_[create|destroy]()   To initialize/release this subsystem
+ *
+ * wa_nep_cb()                 Callback for the notification
+ *                                endpoint; when data is ready, this
+ *                                does the dispatching.
+ */
+#include <linux/workqueue.h>
+#include <linux/ctype.h>
+#include <linux/uwb/debug.h>
+#include "wa-hc.h"
+#include "wusbhc.h"
+
+/* Structure for queueing notifications to the workqueue */
+struct wa_notif_work {
+	struct work_struct work;
+	struct wahc *wa;
+	size_t size;
+	u8 data[];
+};
+
+/*
+ * Process incoming notifications from the WA's Notification EndPoint
+ * [the wuswad daemon, basically]
+ *
+ * @_nw:	Pointer to a descriptor which has the pointer to the
+ * 		@wa, the size of the buffer and the work queue
+ * 		structure (so we can free all when done).
+ * @returns     0 if ok, < 0 errno code on error.
+ *
+ * All notifications follow the same format; they need to start with a
+ * 'struct wa_notif_hdr' header, so it is easy to parse through
+ * them. We just break the buffer in individual notifications (the
+ * standard doesn't say if it can be done or is forbidden, so we are
+ * cautious) and dispatch each.
+ *
+ * So the handling layers are is:
+ *
+ *   WA specific notification (from NEP)
+ *      Device Notification Received -> wa_handle_notif_dn()
+ *        WUSB Device notification generic handling
+ *      BPST Adjustment -> wa_handle_notif_bpst_adj()
+ *      ... -> ...
+ *
+ * @wa has to be referenced
+ */
+static void wa_notif_dispatch(struct work_struct *ws)
+{
+	void *itr;
+	u8 missing = 0;
+	struct wa_notif_work *nw = container_of(ws, struct wa_notif_work, work);
+	struct wahc *wa = nw->wa;
+	struct wa_notif_hdr *notif_hdr;
+	size_t size;
+
+	struct device *dev = &wa->usb_iface->dev;
+
+#if 0
+	/* FIXME: need to check for this??? */
+	if (usb_hcd->state == HC_STATE_QUIESCING)	/* Going down? */
+		goto out;				/* screw it */
+#endif
+	atomic_dec(&wa->notifs_queued);		/* Throttling ctl */
+	dev = &wa->usb_iface->dev;
+	size = nw->size;
+	itr = nw->data;
+
+	while (size) {
+		if (size < sizeof(*notif_hdr)) {
+			missing = sizeof(*notif_hdr) - size;
+			goto exhausted_buffer;
+		}
+		notif_hdr = itr;
+		if (size < notif_hdr->bLength)
+			goto exhausted_buffer;
+		itr += notif_hdr->bLength;
+		size -= notif_hdr->bLength;
+		/* Dispatch the notification [don't use itr or size!] */
+		switch (notif_hdr->bNotifyType) {
+		case HWA_NOTIF_DN: {
+			struct hwa_notif_dn *hwa_dn;
+			hwa_dn = container_of(notif_hdr, struct hwa_notif_dn,
+					      hdr);
+			wusbhc_handle_dn(wa->wusb, hwa_dn->bSourceDeviceAddr,
+					 hwa_dn->dndata,
+					 notif_hdr->bLength - sizeof(*hwa_dn));
+			break;
+		}
+		case WA_NOTIF_TRANSFER:
+			wa_handle_notif_xfer(wa, notif_hdr);
+			break;
+		case DWA_NOTIF_RWAKE:
+		case DWA_NOTIF_PORTSTATUS:
+		case HWA_NOTIF_BPST_ADJ:
+			/* FIXME: unimplemented WA NOTIFs */
+			/* fallthru */
+		default:
+			if (printk_ratelimit()) {
+				dev_err(dev, "HWA: unknown notification 0x%x, "
+					"%zu bytes; discarding\n",
+					notif_hdr->bNotifyType,
+					(size_t)notif_hdr->bLength);
+				dump_bytes(dev, notif_hdr, 16);
+			}
+			break;
+		}
+	}
+out:
+	wa_put(wa);
+	kfree(nw);
+	return;
+
+	/* THIS SHOULD NOT HAPPEN
+	 *
+	 * Buffer exahusted with partial data remaining; just warn and
+	 * discard the data, as this should not happen.
+	 */
+exhausted_buffer:
+	if (!printk_ratelimit())
+		goto out;
+	dev_warn(dev, "HWA: device sent short notification, "
+		 "%d bytes missing; discarding %d bytes.\n",
+		 missing, (int)size);
+	dump_bytes(dev, itr, size);
+	goto out;
+}
+
+/*
+ * Deliver incoming WA notifications to the wusbwa workqueue
+ *
+ * @wa:	Pointer the Wire Adapter Controller Data Streaming
+ *              instance (part of an 'struct usb_hcd').
+ * @size:       Size of the received buffer
+ * @returns     0 if ok, < 0 errno code on error.
+ *
+ * The input buffer is @wa->nep_buffer, with @size bytes
+ * (guaranteed to fit in the allocated space,
+ * @wa->nep_buffer_size).
+ */
+static int wa_nep_queue(struct wahc *wa, size_t size)
+{
+	int result = 0;
+	struct device *dev = &wa->usb_iface->dev;
+	struct wa_notif_work *nw;
+
+	/* dev_fnstart(dev, "(wa %p, size %zu)\n", wa, size); */
+	BUG_ON(size > wa->nep_buffer_size);
+	if (size == 0)
+		goto out;
+	if (atomic_read(&wa->notifs_queued) > 200) {
+		if (printk_ratelimit())
+			dev_err(dev, "Too many notifications queued, "
+				"throttling back\n");
+		goto out;
+	}
+	nw = kzalloc(sizeof(*nw) + size, GFP_ATOMIC);
+	if (nw == NULL) {
+		if (printk_ratelimit())
+			dev_err(dev, "No memory to queue notification\n");
+		goto out;
+	}
+	INIT_WORK(&nw->work, wa_notif_dispatch);
+	nw->wa = wa_get(wa);
+	nw->size = size;
+	memcpy(nw->data, wa->nep_buffer, size);
+	atomic_inc(&wa->notifs_queued);		/* Throttling ctl */
+	queue_work(wusbd, &nw->work);
+out:
+	/* dev_fnend(dev, "(wa %p, size %zu) = result\n", wa, size, result); */
+	return result;
+}
+
+/*
+ * Callback for the notification event endpoint
+ *
+ * Check's that everything is fine and then passes the data to be
+ * queued to the workqueue.
+ */
+static void wa_nep_cb(struct urb *urb)
+{
+	int result;
+	struct wahc *wa = urb->context;
+	struct device *dev = &wa->usb_iface->dev;
+
+	switch (result = urb->status) {
+	case 0:
+		result = wa_nep_queue(wa, urb->actual_length);
+		if (result < 0)
+			dev_err(dev, "NEP: unable to process notification(s): "
+				"%d\n", result);
+		break;
+	case -ECONNRESET:	/* Not an error, but a controlled situation; */
+	case -ENOENT:		/* (we killed the URB)...so, no broadcast */
+	case -ESHUTDOWN:
+		dev_dbg(dev, "NEP: going down %d\n", urb->status);
+		goto out;
+	default:	/* On general errors, we retry unless it gets ugly */
+		if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
+			    EDC_ERROR_TIMEFRAME)) {
+			dev_err(dev, "NEP: URB max acceptable errors "
+				"exceeded, resetting device\n");
+			wa_reset_all(wa);
+			goto out;
+		}
+		dev_err(dev, "NEP: URB error %d\n", urb->status);
+	}
+	result = wa_nep_arm(wa, GFP_ATOMIC);
+	if (result < 0) {
+		dev_err(dev, "NEP: cannot submit URB: %d\n", result);
+		wa_reset_all(wa);
+	}
+out:
+	return;
+}
+
+/*
+ * Initialize @wa's notification and event's endpoint stuff
+ *
+ * This includes the allocating the read buffer, the context ID
+ * allocation bitmap, the URB and submitting the URB.
+ */
+int wa_nep_create(struct wahc *wa, struct usb_interface *iface)
+{
+	int result;
+	struct usb_endpoint_descriptor *epd;
+	struct usb_device *usb_dev = interface_to_usbdev(iface);
+	struct device *dev = &iface->dev;
+
+	edc_init(&wa->nep_edc);
+	epd = &iface->cur_altsetting->endpoint[0].desc;
+	wa->nep_buffer_size = 1024;
+	wa->nep_buffer = kmalloc(wa->nep_buffer_size, GFP_KERNEL);
+	if (wa->nep_buffer == NULL) {
+		dev_err(dev, "Unable to allocate notification's read buffer\n");
+		goto error_nep_buffer;
+	}
+	wa->nep_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (wa->nep_urb == NULL) {
+		dev_err(dev, "Unable to allocate notification URB\n");
+		goto error_urb_alloc;
+	}
+	usb_fill_int_urb(wa->nep_urb, usb_dev,
+			 usb_rcvintpipe(usb_dev, epd->bEndpointAddress),
+			 wa->nep_buffer, wa->nep_buffer_size,
+			 wa_nep_cb, wa, epd->bInterval);
+	result = wa_nep_arm(wa, GFP_KERNEL);
+	if (result < 0) {
+		dev_err(dev, "Cannot submit notification URB: %d\n", result);
+		goto error_nep_arm;
+	}
+	return 0;
+
+error_nep_arm:
+	usb_free_urb(wa->nep_urb);
+error_urb_alloc:
+	kfree(wa->nep_buffer);
+error_nep_buffer:
+	return -ENOMEM;
+}
+
+void wa_nep_destroy(struct wahc *wa)
+{
+	wa_nep_disarm(wa);
+	usb_free_urb(wa->nep_urb);
+	kfree(wa->nep_buffer);
+}