diff options
Diffstat (limited to 'drivers/uwb/neh.c')
| -rw-r--r-- | drivers/uwb/neh.c | 616 |
1 files changed, 616 insertions, 0 deletions
diff --git a/drivers/uwb/neh.c b/drivers/uwb/neh.c new file mode 100644 index 00000000000..91b61480e1e --- /dev/null +++ b/drivers/uwb/neh.c @@ -0,0 +1,616 @@ +/* + * WUSB Wire Adapter: Radio Control Interface (WUSB[8]) + * Notification and Event Handling + * + * 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. + * + * + * The RC interface of the Host Wire Adapter (USB dongle) or WHCI PCI + * card delivers a stream of notifications and events to the + * notification end event endpoint or area. This code takes care of + * getting a buffer with that data, breaking it up in separate + * notifications and events and then deliver those. + * + * Events are answers to commands and they carry a context ID that + * associates them to the command. Notifications are that, + * notifications, they come out of the blue and have a context ID of + * zero. Think of the context ID kind of like a handler. The + * uwb_rc_neh_* code deals with managing context IDs. + * + * This is why you require a handle to operate on a UWB host. When you + * open a handle a context ID is assigned to you. + * + * So, as it is done is: + * + * 1. Add an event handler [uwb_rc_neh_add()] (assigns a ctx id) + * 2. Issue command [rc->cmd(rc, ...)] + * 3. Arm the timeout timer [uwb_rc_neh_arm()] + * 4, Release the reference to the neh [uwb_rc_neh_put()] + * 5. Wait for the callback + * 6. Command result (RCEB) is passed to the callback + * + * If (2) fails, you should remove the handle [uwb_rc_neh_rm()] + * instead of arming the timer. + * + * Handles are for using in *serialized* code, single thread. + * + * When the notification/event comes, the IRQ handler/endpoint + * callback passes the data read to uwb_rc_neh_grok() which will break + * it up in a discrete series of events, look up who is listening for + * them and execute the pertinent callbacks. + * + * If the reader detects an error while reading the data stream, call + * uwb_rc_neh_error(). + * + * CONSTRAINTS/ASSUMPTIONS: + * + * - Most notifications/events are small (less thank .5k), copying + * around is ok. + * + * - Notifications/events are ALWAYS smaller than PAGE_SIZE + * + * - Notifications/events always come in a single piece (ie: a buffer + * will always contain entire notifications/events). + * + * - we cannot know in advance how long each event is (because they + * lack a length field in their header--smart move by the standards + * body, btw). So we need a facility to get the event size given the + * header. This is what the EST code does (notif/Event Size + * Tables), check nest.c--as well, you can associate the size to + * the handle [w/ neh->extra_size()]. + * + * - Most notifications/events are fixed size; only a few are variable + * size (NEST takes care of that). + * + * - Listeners of events expect them, so they usually provide a + * buffer, as they know the size. Listeners to notifications don't, + * so we allocate their buffers dynamically. + */ +#include <linux/kernel.h> +#include <linux/timer.h> +#include <linux/err.h> + +#include "uwb-internal.h" +#define D_LOCAL 0 +#include <linux/uwb/debug.h> + +/* + * UWB Radio Controller Notification/Event Handle + * + * Represents an entity waiting for an event coming from the UWB Radio + * Controller with a given context id (context) and type (evt_type and + * evt). On reception of the notification/event, the callback (cb) is + * called with the event. + * + * If the timer expires before the event is received, the callback is + * called with -ETIMEDOUT as the event size. + */ +struct uwb_rc_neh { + struct kref kref; + + struct uwb_rc *rc; + u8 evt_type; + __le16 evt; + u8 context; + uwb_rc_cmd_cb_f cb; + void *arg; + + struct timer_list timer; + struct list_head list_node; +}; + +static void uwb_rc_neh_timer(unsigned long arg); + +static void uwb_rc_neh_release(struct kref *kref) +{ + struct uwb_rc_neh *neh = container_of(kref, struct uwb_rc_neh, kref); + + kfree(neh); +} + +static void uwb_rc_neh_get(struct uwb_rc_neh *neh) +{ + kref_get(&neh->kref); +} + +/** + * uwb_rc_neh_put - release reference to a neh + * @neh: the neh + */ +void uwb_rc_neh_put(struct uwb_rc_neh *neh) +{ + kref_put(&neh->kref, uwb_rc_neh_release); +} + + +/** + * Assigns @neh a context id from @rc's pool + * + * @rc: UWB Radio Controller descriptor; @rc->neh_lock taken + * @neh: Notification/Event Handle + * @returns 0 if context id was assigned ok; < 0 errno on error (if + * all the context IDs are taken). + * + * (assumes @wa is locked). + * + * NOTE: WUSB spec reserves context ids 0x00 for notifications and + * 0xff is invalid, so they must not be used. Initialization + * fills up those two in the bitmap so they are not allocated. + * + * We spread the allocation around to reduce the posiblity of two + * consecutive opened @neh's getting the same context ID assigned (to + * avoid surprises with late events that timed out long time ago). So + * first we search from where @rc->ctx_roll is, if not found, we + * search from zero. + */ +static +int __uwb_rc_ctx_get(struct uwb_rc *rc, struct uwb_rc_neh *neh) +{ + int result; + result = find_next_zero_bit(rc->ctx_bm, UWB_RC_CTX_MAX, + rc->ctx_roll++); + if (result < UWB_RC_CTX_MAX) + goto found; + result = find_first_zero_bit(rc->ctx_bm, UWB_RC_CTX_MAX); + if (result < UWB_RC_CTX_MAX) + goto found; + return -ENFILE; +found: + set_bit(result, rc->ctx_bm); + neh->context = result; + return 0; +} + + +/** Releases @neh's context ID back to @rc (@rc->neh_lock is locked). */ +static +void __uwb_rc_ctx_put(struct uwb_rc *rc, struct uwb_rc_neh *neh) +{ + struct device *dev = &rc->uwb_dev.dev; + if (neh->context == 0) + return; + if (test_bit(neh->context, rc->ctx_bm) == 0) { + dev_err(dev, "context %u not set in bitmap\n", + neh->context); + WARN_ON(1); + } + clear_bit(neh->context, rc->ctx_bm); + neh->context = 0; +} + +/** + * uwb_rc_neh_add - add a neh for a radio controller command + * @rc: the radio controller + * @cmd: the radio controller command + * @expected_type: the type of the expected response event + * @expected_event: the expected event ID + * @cb: callback for when the event is received + * @arg: argument for the callback + * + * Creates a neh and adds it to the list of those waiting for an + * event. A context ID will be assigned to the command. + */ +struct uwb_rc_neh *uwb_rc_neh_add(struct uwb_rc *rc, struct uwb_rccb *cmd, + u8 expected_type, u16 expected_event, + uwb_rc_cmd_cb_f cb, void *arg) +{ + int result; + unsigned long flags; + struct device *dev = &rc->uwb_dev.dev; + struct uwb_rc_neh *neh; + + neh = kzalloc(sizeof(*neh), GFP_KERNEL); + if (neh == NULL) { + result = -ENOMEM; + goto error_kzalloc; + } + + kref_init(&neh->kref); + INIT_LIST_HEAD(&neh->list_node); + init_timer(&neh->timer); + neh->timer.function = uwb_rc_neh_timer; + neh->timer.data = (unsigned long)neh; + + neh->rc = rc; + neh->evt_type = expected_type; + neh->evt = cpu_to_le16(expected_event); + neh->cb = cb; + neh->arg = arg; + + spin_lock_irqsave(&rc->neh_lock, flags); + result = __uwb_rc_ctx_get(rc, neh); + if (result >= 0) { + cmd->bCommandContext = neh->context; + list_add_tail(&neh->list_node, &rc->neh_list); + uwb_rc_neh_get(neh); + } + spin_unlock_irqrestore(&rc->neh_lock, flags); + if (result < 0) + goto error_ctx_get; + + return neh; + +error_ctx_get: + kfree(neh); +error_kzalloc: + dev_err(dev, "cannot open handle to radio controller: %d\n", result); + return ERR_PTR(result); +} + +static void __uwb_rc_neh_rm(struct uwb_rc *rc, struct uwb_rc_neh *neh) +{ + del_timer(&neh->timer); + __uwb_rc_ctx_put(rc, neh); + list_del(&neh->list_node); +} + +/** + * uwb_rc_neh_rm - remove a neh. + * @rc: the radio controller + * @neh: the neh to remove + * + * Remove an active neh immediately instead of waiting for the event + * (or a time out). + */ +void uwb_rc_neh_rm(struct uwb_rc *rc, struct uwb_rc_neh *neh) +{ + unsigned long flags; + + spin_lock_irqsave(&rc->neh_lock, flags); + __uwb_rc_neh_rm(rc, neh); + spin_unlock_irqrestore(&rc->neh_lock, flags); + + uwb_rc_neh_put(neh); +} + +/** + * uwb_rc_neh_arm - arm an event handler timeout timer + * + * @rc: UWB Radio Controller + * @neh: Notification/event handler for @rc + * + * The timer is only armed if the neh is active. + */ +void uwb_rc_neh_arm(struct uwb_rc *rc, struct uwb_rc_neh *neh) +{ + unsigned long flags; + + spin_lock_irqsave(&rc->neh_lock, flags); + if (neh->context) + mod_timer(&neh->timer, + jiffies + msecs_to_jiffies(UWB_RC_CMD_TIMEOUT_MS)); + spin_unlock_irqrestore(&rc->neh_lock, flags); +} + +static void uwb_rc_neh_cb(struct uwb_rc_neh *neh, struct uwb_rceb *rceb, size_t size) +{ + (*neh->cb)(neh->rc, neh->arg, rceb, size); + uwb_rc_neh_put(neh); +} + +static bool uwb_rc_neh_match(struct uwb_rc_neh *neh, const struct uwb_rceb *rceb) +{ + return neh->evt_type == rceb->bEventType + && neh->evt == rceb->wEvent + && neh->context == rceb->bEventContext; +} + +/** + * Find the handle waiting for a RC Radio Control Event + * + * @rc: UWB Radio Controller + * @rceb: Pointer to the RCEB buffer + * @event_size: Pointer to the size of the RCEB buffer. Might be + * adjusted to take into account the @neh->extra_size + * settings. + * + * If the listener has no buffer (NULL buffer), one is allocated for + * the right size (the amount of data received). @neh->ptr will point + * to the event payload, which always starts with a 'struct + * uwb_rceb'. kfree() it when done. + */ +static +struct uwb_rc_neh *uwb_rc_neh_lookup(struct uwb_rc *rc, + const struct uwb_rceb *rceb) +{ + struct uwb_rc_neh *neh = NULL, *h; + unsigned long flags; + + spin_lock_irqsave(&rc->neh_lock, flags); + + list_for_each_entry(h, &rc->neh_list, list_node) { + if (uwb_rc_neh_match(h, rceb)) { + neh = h; + break; + } + } + + if (neh) + __uwb_rc_neh_rm(rc, neh); + + spin_unlock_irqrestore(&rc->neh_lock, flags); + + return neh; +} + + +/** + * Process notifications coming from the radio control interface + * + * @rc: UWB Radio Control Interface descriptor + * @neh: Notification/Event Handler @neh->ptr points to + * @uwb_evt->buffer. + * + * This function is called by the event/notif handling subsystem when + * notifications arrive (hwarc_probe() arms a notification/event handle + * that calls back this function for every received notification; this + * function then will rearm itself). + * + * Notification data buffers are dynamically allocated by the NEH + * handling code in neh.c [uwb_rc_neh_lookup()]. What is actually + * allocated is space to contain the notification data. + * + * Buffers are prefixed with a Radio Control Event Block (RCEB) as + * defined by the WUSB Wired-Adapter Radio Control interface. We + * just use it for the notification code. + * + * On each case statement we just transcode endianess of the different + * fields. We declare a pointer to a RCI definition of an event, and + * then to a UWB definition of the same event (which are the same, + * remember). Event if we use different pointers + */ +static +void uwb_rc_notif(struct uwb_rc *rc, struct uwb_rceb *rceb, ssize_t size) +{ + struct device *dev = &rc->uwb_dev.dev; + struct uwb_event *uwb_evt; + + if (size == -ESHUTDOWN) + return; + if (size < 0) { + dev_err(dev, "ignoring event with error code %zu\n", + size); + return; + } + + uwb_evt = kzalloc(sizeof(*uwb_evt), GFP_ATOMIC); + if (unlikely(uwb_evt == NULL)) { + dev_err(dev, "no memory to queue event 0x%02x/%04x/%02x\n", + rceb->bEventType, le16_to_cpu(rceb->wEvent), + rceb->bEventContext); + return; + } + uwb_evt->rc = __uwb_rc_get(rc); /* will be put by uwbd's uwbd_event_handle() */ + uwb_evt->ts_jiffies = jiffies; + uwb_evt->type = UWB_EVT_TYPE_NOTIF; + uwb_evt->notif.size = size; + uwb_evt->notif.rceb = rceb; + + switch (le16_to_cpu(rceb->wEvent)) { + /* Trap some vendor specific events + * + * FIXME: move this to handling in ptc-est, where we + * register a NULL event handler for these two guys + * using the Intel IDs. + */ + case 0x0103: + dev_info(dev, "FIXME: DEVICE ADD\n"); + return; + case 0x0104: + dev_info(dev, "FIXME: DEVICE RM\n"); + return; + default: + break; + } + + uwbd_event_queue(uwb_evt); +} + +static void uwb_rc_neh_grok_event(struct uwb_rc *rc, struct uwb_rceb *rceb, size_t size) +{ + struct device *dev = &rc->uwb_dev.dev; + struct uwb_rc_neh *neh; + struct uwb_rceb *notif; + + if (rceb->bEventContext == 0) { + notif = kmalloc(size, GFP_ATOMIC); + if (notif) { + memcpy(notif, rceb, size); + uwb_rc_notif(rc, notif, size); + } else + dev_err(dev, "event 0x%02x/%04x/%02x (%zu bytes): no memory\n", + rceb->bEventType, le16_to_cpu(rceb->wEvent), + rceb->bEventContext, size); + } else { + neh = uwb_rc_neh_lookup(rc, rceb); + if (neh) + uwb_rc_neh_cb(neh, rceb, size); + else if (printk_ratelimit()) + dev_warn(dev, "event 0x%02x/%04x/%02x (%zu bytes): nobody cared\n", + rceb->bEventType, le16_to_cpu(rceb->wEvent), + rceb->bEventContext, size); + } +} + +/** + * Given a buffer with one or more UWB RC events/notifications, break + * them up and dispatch them. + * + * @rc: UWB Radio Controller + * @buf: Buffer with the stream of notifications/events + * @buf_size: Amount of data in the buffer + * + * Note each notification/event starts always with a 'struct + * uwb_rceb', so the minimum size if 4 bytes. + * + * The device may pass us events formatted differently than expected. + * These are first filtered, potentially creating a new event in a new + * memory location. If a new event is created by the filter it is also + * freed here. + * + * For each notif/event, tries to guess the size looking at the EST + * tables, then looks for a neh that is waiting for that event and if + * found, copies the payload to the neh's buffer and calls it back. If + * not, the data is ignored. + * + * Note that if we can't find a size description in the EST tables, we + * still might find a size in the 'neh' handle in uwb_rc_neh_lookup(). + * + * Assumptions: + * + * @rc->neh_lock is NOT taken + * + * We keep track of various sizes here: + * size: contains the size of the buffer that is processed for the + * incoming event. this buffer may contain events that are not + * formatted as WHCI. + * real_size: the actual space taken by this event in the buffer. + * We need to keep track of the real size of an event to be able to + * advance the buffer correctly. + * event_size: the size of the event as expected by the core layer + * [OR] the size of the event after filtering. if the filtering + * created a new event in a new memory location then this is + * effectively the size of a new event buffer + */ +void uwb_rc_neh_grok(struct uwb_rc *rc, void *buf, size_t buf_size) +{ + struct device *dev = &rc->uwb_dev.dev; + void *itr; + struct uwb_rceb *rceb; + size_t size, real_size, event_size; + int needtofree; + + d_fnstart(3, dev, "(rc %p buf %p %zu buf_size)\n", rc, buf, buf_size); + d_printf(2, dev, "groking event block: %zu bytes\n", buf_size); + itr = buf; + size = buf_size; + while (size > 0) { + if (size < sizeof(*rceb)) { + dev_err(dev, "not enough data in event buffer to " + "process incoming events (%zu left, minimum is " + "%zu)\n", size, sizeof(*rceb)); + break; + } + + rceb = itr; + if (rc->filter_event) { + needtofree = rc->filter_event(rc, &rceb, size, + &real_size, &event_size); + if (needtofree < 0 && needtofree != -ENOANO) { + dev_err(dev, "BUG: Unable to filter event " + "(0x%02x/%04x/%02x) from " + "device. \n", rceb->bEventType, + le16_to_cpu(rceb->wEvent), + rceb->bEventContext); + break; + } + } else + needtofree = -ENOANO; + /* do real processing if there was no filtering or the + * filtering didn't act */ + if (needtofree == -ENOANO) { + ssize_t ret = uwb_est_find_size(rc, rceb, size); + if (ret < 0) + break; + if (ret > size) { + dev_err(dev, "BUG: hw sent incomplete event " + "0x%02x/%04x/%02x (%zd bytes), only got " + "%zu bytes. We don't handle that.\n", + rceb->bEventType, le16_to_cpu(rceb->wEvent), + rceb->bEventContext, ret, size); + break; + } + real_size = event_size = ret; + } + uwb_rc_neh_grok_event(rc, rceb, event_size); + + if (needtofree == 1) + kfree(rceb); + + itr += real_size; + size -= real_size; + d_printf(2, dev, "consumed %zd bytes, %zu left\n", + event_size, size); + } + d_fnend(3, dev, "(rc %p buf %p %zu buf_size) = void\n", rc, buf, buf_size); +} +EXPORT_SYMBOL_GPL(uwb_rc_neh_grok); + + +/** + * The entity that reads from the device notification/event channel has + * detected an error. + * + * @rc: UWB Radio Controller + * @error: Errno error code + * + */ +void uwb_rc_neh_error(struct uwb_rc *rc, int error) +{ + struct uwb_rc_neh *neh, *next; + unsigned long flags; + + BUG_ON(error >= 0); + spin_lock_irqsave(&rc->neh_lock, flags); + list_for_each_entry_safe(neh, next, &rc->neh_list, list_node) { + __uwb_rc_neh_rm(rc, neh); + uwb_rc_neh_cb(neh, NULL, error); + } + spin_unlock_irqrestore(&rc->neh_lock, flags); +} +EXPORT_SYMBOL_GPL(uwb_rc_neh_error); + + +static void uwb_rc_neh_timer(unsigned long arg) +{ + struct uwb_rc_neh *neh = (struct uwb_rc_neh *)arg; + struct uwb_rc *rc = neh->rc; + unsigned long flags; + + spin_lock_irqsave(&rc->neh_lock, flags); + __uwb_rc_neh_rm(rc, neh); + spin_unlock_irqrestore(&rc->neh_lock, flags); + + uwb_rc_neh_cb(neh, NULL, -ETIMEDOUT); +} + +/** Initializes the @rc's neh subsystem + */ +void uwb_rc_neh_create(struct uwb_rc *rc) +{ + spin_lock_init(&rc->neh_lock); + INIT_LIST_HEAD(&rc->neh_list); + set_bit(0, rc->ctx_bm); /* 0 is reserved (see [WUSB] table 8-65) */ + set_bit(0xff, rc->ctx_bm); /* and 0xff is invalid */ + rc->ctx_roll = 1; +} + + +/** Release's the @rc's neh subsystem */ +void uwb_rc_neh_destroy(struct uwb_rc *rc) +{ + unsigned long flags; + struct uwb_rc_neh *neh, *next; + + spin_lock_irqsave(&rc->neh_lock, flags); + list_for_each_entry_safe(neh, next, &rc->neh_list, list_node) { + __uwb_rc_neh_rm(rc, neh); + uwb_rc_neh_put(neh); + } + spin_unlock_irqrestore(&rc->neh_lock, flags); +} |