/*
* 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/slab.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:
dev_err(dev, "HWA: unknown notification 0x%x, "
"%zu bytes; discarding\n",
notif_hdr->bNotifyType,
(size_t)notif_hdr->bLength);
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:
dev_warn(dev, "HWA: device sent short notification, "
"%d bytes missing; discarding %d bytes.\n",
missing, (int)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);
}