diff options
Diffstat (limited to 'drivers/uwb/neh.c')
-rw-r--r-- | drivers/uwb/neh.c | 606 |
1 files changed, 0 insertions, 606 deletions
diff --git a/drivers/uwb/neh.c b/drivers/uwb/neh.c deleted file mode 100644 index 1695584be412..000000000000 --- a/drivers/uwb/neh.c +++ /dev/null @@ -1,606 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* - * 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> - * - * 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/slab.h> -#include <linux/err.h> -#include <linux/export.h> - -#include "uwb-internal.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; - u8 completed; - uwb_rc_cmd_cb_f cb; - void *arg; - - struct timer_list timer; - struct list_head list_node; -}; - -static void uwb_rc_neh_timer(struct timer_list *t); - -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 possibility 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); - timer_setup(&neh->timer, uwb_rc_neh_timer, 0); - - 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) -{ - __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); - - del_timer_sync(&neh->timer); - 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; - - 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; - unsigned long flags; - - 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) { - spin_lock_irqsave(&rc->neh_lock, flags); - /* to guard against a timeout */ - neh->completed = 1; - del_timer(&neh->timer); - spin_unlock_irqrestore(&rc->neh_lock, flags); - uwb_rc_neh_cb(neh, rceb, size); - } else - 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; - - 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; - } -} -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; - unsigned long flags; - - for (;;) { - spin_lock_irqsave(&rc->neh_lock, flags); - if (list_empty(&rc->neh_list)) { - spin_unlock_irqrestore(&rc->neh_lock, flags); - break; - } - neh = list_first_entry(&rc->neh_list, struct uwb_rc_neh, list_node); - __uwb_rc_neh_rm(rc, neh); - spin_unlock_irqrestore(&rc->neh_lock, flags); - - del_timer_sync(&neh->timer); - uwb_rc_neh_cb(neh, NULL, error); - } -} -EXPORT_SYMBOL_GPL(uwb_rc_neh_error); - - -static void uwb_rc_neh_timer(struct timer_list *t) -{ - struct uwb_rc_neh *neh = from_timer(neh, t, timer); - struct uwb_rc *rc = neh->rc; - unsigned long flags; - - spin_lock_irqsave(&rc->neh_lock, flags); - if (neh->completed) { - spin_unlock_irqrestore(&rc->neh_lock, flags); - return; - } - if (neh->context) - __uwb_rc_neh_rm(rc, neh); - else - neh = NULL; - spin_unlock_irqrestore(&rc->neh_lock, flags); - - if (neh) - 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; - - for (;;) { - spin_lock_irqsave(&rc->neh_lock, flags); - if (list_empty(&rc->neh_list)) { - spin_unlock_irqrestore(&rc->neh_lock, flags); - break; - } - neh = list_first_entry(&rc->neh_list, struct uwb_rc_neh, list_node); - __uwb_rc_neh_rm(rc, neh); - spin_unlock_irqrestore(&rc->neh_lock, flags); - - del_timer_sync(&neh->timer); - uwb_rc_neh_put(neh); - } -} |