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 00000000000..3f542990c73
--- /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);
+}