/*
* Ultra Wide Band
* UWB API
*
* 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.
*
*
* FIXME: doc: overview of the API, different parts and pointers
*/
#ifndef __LINUX__UWB_H__
#define __LINUX__UWB_H__
#include <linux/limits.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/timer.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/uwb/spec.h>
struct uwb_dev;
struct uwb_beca_e;
struct uwb_rc;
struct uwb_rsv;
struct uwb_dbg;
/**
* struct uwb_dev - a UWB Device
* @rc: UWB Radio Controller that discovered the device (kind of its
* parent).
* @bce: a beacon cache entry for this device; or NULL if the device
* is a local radio controller.
* @mac_addr: the EUI-48 address of this device.
* @dev_addr: the current DevAddr used by this device.
* @beacon_slot: the slot number the beacon is using.
* @streams: bitmap of streams allocated to reservations targeted at
* this device. For an RC, this is the streams allocated for
* reservations targeted at DevAddrs.
*
* A UWB device may either by a neighbor or part of a local radio
* controller.
*/
struct uwb_dev {
struct mutex mutex;
struct list_head list_node;
struct device dev;
struct uwb_rc *rc; /* radio controller */
struct uwb_beca_e *bce; /* Beacon Cache Entry */
struct uwb_mac_addr mac_addr;
struct uwb_dev_addr dev_addr;
int beacon_slot;
DECLARE_BITMAP(streams, UWB_NUM_STREAMS);
};
#define to_uwb_dev(d) container_of(d, struct uwb_dev, dev)
/**
* UWB HWA/WHCI Radio Control {Command|Event} Block context IDs
*
* RC[CE]Bs have a 'context ID' field that matches the command with
* the event received to confirm it.
*
* Maximum number of context IDs
*/
enum { UWB_RC_CTX_MAX = 256 };
/** Notification chain head for UWB generated events to listeners */
struct uwb_notifs_chain {
struct list_head list;
struct mutex mutex;
};
/* Beacon cache list */
struct uwb_beca {
struct list_head list;
size_t entries;
struct mutex mutex;
};
/* Event handling thread. */
struct uwbd {
int pid;
struct task_struct *task;
wait_queue_head_t wq;
struct list_head event_list;
spinlock_t event_list_lock;
};
/**
* struct uwb_mas_bm - a bitmap of all MAS in a superframe
* @bm: a bitmap of length #UWB_NUM_MAS
*/
struct uwb_mas_bm {
DECLARE_BITMAP(bm, UWB_NUM_MAS);
};
/**
* uwb_rsv_state - UWB Reservation state.
*
* NONE - reservation is not active (no DRP IE being transmitted).
*
* Owner reservation states:
*
* INITIATED - owner has sent an initial DRP request.
* PENDING - target responded with pending Reason Code.
* MODIFIED - reservation manager is modifying an established
* reservation with a different MAS allocation.
* ESTABLISHED - the reservation has been successfully negotiated.
*
* Target reservation states:
*
* DENIED - request is denied.
* ACCEPTED - request is accepted.
* PENDING - PAL has yet to make a decision to whether to accept or
* deny.
*
* FIXME: further target states TBD.
*/
enum uwb_rsv_state {
UWB_RSV_STATE_NONE,
UWB_RSV_STATE_O_INITIATED,
UWB_RSV_STATE_O_PENDING,
UWB_RSV_STATE_O_MODIFIED,
UWB_RSV_STATE_O_ESTABLISHED,
UWB_RSV_STATE_T_ACCEPTED,
UWB_RSV_STATE_T_DENIED,
UWB_RSV_STATE_T_PENDING,
UWB_RSV_STATE_LAST,
};
enum uwb_rsv_target_type {
UWB_RSV_TARGET_DEV,
UWB_RSV_TARGET_DEVADDR,
};
/**
* struct uwb_rsv_target - the target of a reservation.
*
* Reservations unicast and targeted at a single device
* (UWB_RSV_TARGET_DEV); or (e.g., in the case of WUSB) targeted at a
* specific (private) DevAddr (UWB_RSV_TARGET_DEVADDR).
*/
struct uwb_rsv_target {
enum uwb_rsv_target_type type;
union {
struct uwb_dev *dev;
struct uwb_dev_addr devaddr;
};
};
/*
* Number of streams reserved for reservations targeted at DevAddrs.
*/
#define UWB_NUM_GLOBAL_STREAMS 1
typedef void (*uwb_rsv_cb_f)(struct uwb_rsv *rsv);
/**
* struct uwb_rsv - a DRP reservation
*
* Data structure management:
*
* @rc: the radio controller this reservation is for
* (as target or owner)
* @rc_node: a list node for the RC
* @pal_node: a list node for the PAL
*
* Owner and target parameters:
*
* @owner: the UWB device owning this reservation
* @target: the target UWB device
* @type: reservation type
*
* Owner parameters:
*
* @max_mas: maxiumum number of MAS
* @min_mas: minimum number of MAS
* @sparsity: owner selected sparsity
* @is_multicast: true iff multicast
*
* @callback: callback function when the reservation completes
* @pal_priv: private data for the PAL making the reservation
*
* Reservation status:
*
* @status: negotiation status
* @stream: stream index allocated for this reservation
* @mas: reserved MAS
* @drp_ie: the DRP IE
* @ie_valid: true iff the DRP IE matches the reservation parameters
*
* DRP reservations are uniquely identified by the owner, target and
* stream index. However, when using a DevAddr as a target (e.g., for
* a WUSB cluster reservation) the responses may be received from
* devices with different DevAddrs. In this case, reservations are
* uniquely identified by just the stream index. A number of stream
* indexes (UWB_NUM_GLOBAL_STREAMS) are reserved for this.
*/
struct uwb_rsv {
struct uwb_rc *rc;
struct list_head rc_node;
struct list_head pal_node;
struct kref kref;
struct uwb_dev *owner;
struct uwb_rsv_target target;
enum uwb_drp_type type;
int max_mas;
int min_mas;
int sparsity;
bool is_multicast;
uwb_rsv_cb_f callback;
void *pal_priv;
enum uwb_rsv_state state;
u8 stream;
struct uwb_mas_bm mas;
struct uwb_ie_drp *drp_ie;
bool ie_valid;
struct timer_list timer;
bool expired;
};
static const
struct uwb_mas_bm uwb_mas_bm_zero = { .bm = { 0 } };
static inline void uwb_mas_bm_copy_le(void *dst, const struct uwb_mas_bm *mas)
{
bitmap_copy_le(dst, mas->bm, UWB_NUM_MAS);
}
/**
* struct uwb_drp_avail - a radio controller's view of MAS usage
* @global: MAS unused by neighbors (excluding reservations targetted
* or owned by the local radio controller) or the beaon period
* @local: MAS unused by local established reservations
* @pending: MAS unused by local pending reservations
* @ie: DRP Availability IE to be included in the beacon
* @ie_valid: true iff @ie is valid and does not need to regenerated from
* @global and @local
*
* Each radio controller maintains a view of MAS usage or
* availability. MAS available for a new reservation are determined
* from the intersection of @global, @local, and @pending.
*
* The radio controller must transmit a DRP Availability IE that's the
* intersection of @global and @local.
*
* A set bit indicates the MAS is unused and available.
*
* rc->rsvs_mutex should be held before accessing this data structure.
*
* [ECMA-368] section 17.4.3.
*/
struct uwb_drp_avail {
DECLARE_BITMAP(global, UWB_NUM_MAS);
DECLARE_BITMAP(local, UWB_NUM_MAS);
DECLARE_BITMAP(pending, UWB_NUM_MAS);
struct uwb_ie_drp_avail ie;
bool ie_valid;
};
const char *uwb_rsv_state_str(enum uwb_rsv_state state);
const char *uwb_rsv_type_str(enum uwb_drp_type type);
struct uwb_rsv *uwb_rsv_create(struct uwb_rc *rc, uwb_rsv_cb_f cb,
void *pal_priv);
void uwb_rsv_destroy(struct uwb_rsv *rsv);
int uwb_rsv_establish(struct uwb_rsv *rsv);
int uwb_rsv_modify(struct uwb_rsv *rsv,
int max_mas, int min_mas, int sparsity);
void uwb_rsv_terminate(struct uwb_rsv *rsv);
void uwb_rsv_accept(struct uwb_rsv *rsv, uwb_rsv_cb_f cb, void *pal_priv);
/**
* Radio Control Interface instance
*
*
* Life cycle rules: those of the UWB Device.
*
* @index: an index number for this radio controller, as used in the
* device name.
* @version: version of protocol supported by this device
* @priv: Backend implementation; rw with uwb_dev.dev.sem taken.
* @cmd: Backend implementation to execute commands; rw and call
* only with uwb_dev.dev.sem taken.
* @reset: Hardware reset of radio controller and any PAL controllers.
* @filter: Backend implementation to manipulate data to and from device
* to be compliant to specification assumed by driver (WHCI
* 0.95).
*
* uwb_dev.dev.mutex is used to execute commands and update
* the corresponding structures; can't use a spinlock
* because rc->cmd() can sleep.
* @ies: This is a dynamically allocated array cacheing the
* IEs (settable by the host) that the beacon of this
* radio controller is currently sending.
*
* In reality, we store here the full command we set to
* the radio controller (which is basically a command
* prefix followed by all the IEs the beacon currently
* contains). This way we don't have to realloc and
* memcpy when setting it.
*
* We set this up in uwb_rc_ie_setup(), where we alloc
* this struct, call get_ie() [so we know which IEs are
* currently being sent, if any].
*
* @ies_capacity:Amount of space (in bytes) allocated in @ies. The
* amount used is given by sizeof(*ies) plus ies->wIELength
* (which is a little endian quantity all the time).
* @ies_mutex: protect the IE cache
* @dbg: information for the debug interface
*/
struct uwb_rc {
struct uwb_dev uwb_dev;
int index;
u16 version;
struct module *owner;
void *priv;
int (*start)(struct uwb_rc *rc);
void (*stop)(struct uwb_rc *rc);
int (*cmd)(struct uwb_rc *, const struct uwb_rccb *, size_t);
int (*reset)(struct uwb_rc *rc);
int (*filter_cmd)(struct uwb_rc *, struct uwb_rccb **, size_t *);
int (*filter_event)(struct uwb_rc *, struct uwb_rceb **, const size_t,
size_t *, size_t *);
spinlock_t neh_lock; /* protects neh_* and ctx_* */
struct list_head neh_list; /* Open NE handles */
unsigned long ctx_bm[UWB_RC_CTX_MAX / 8 / sizeof(unsigned long)];
u8 ctx_roll;
int beaconing; /* Beaconing state [channel number] */
int scanning;
enum uwb_scan_type scan_type:3;
unsigned ready:1;
struct uwb_notifs_chain notifs_chain;
struct uwb_beca uwb_beca;
struct uwbd uwbd;
struct uwb_drp_avail drp_avail;
struct list_head reservations;
struct mutex rsvs_mutex;
struct workqueue_struct *rsv_workq;
struct work_struct rsv_update_work;
struct mutex ies_mutex;
struct uwb_rc_cmd_set_ie *ies;
size_t ies_capacity;
spinlock_t pal_lock;
struct list_head pals;
struct uwb_dbg *dbg;
};
/**
* struct uwb_pal - a UWB PAL
* @name: descriptive name for this PAL (wushc, wlp, etc.).
* @device: a device for the PAL. Used to link the PAL and the radio
* controller in sysfs.
* @new_rsv: called when a peer requests a reservation (may be NULL if
* the PAL cannot accept reservation requests).
*
* A Protocol Adaptation Layer (PAL) is a user of the WiMedia UWB
* radio platform (e.g., WUSB, WLP or Bluetooth UWB AMP).
*
* The PALs using a radio controller must register themselves to
* permit the UWB stack to coordinate usage of the radio between the
* various PALs or to allow PALs to response to certain requests from
* peers.
*
* A struct uwb_pal should be embedded in a containing structure
* belonging to the PAL and initialized with uwb_pal_init()). Fields
* should be set appropriately by the PAL before registering the PAL
* with uwb_pal_register().
*/
struct uwb_pal {
struct list_head node;
const char *name;
struct device *device;
void (*new_rsv)(struct uwb_pal *pal, struct uwb_rsv *rsv);
};
void uwb_pal_init(struct uwb_pal *pal);
int uwb_pal_register(struct uwb_rc *rc, struct uwb_pal *pal);
void uwb_pal_unregister(struct uwb_rc *rc, struct uwb_pal *pal);
/*
* General public API
*
* This API can be used by UWB device drivers or by those implementing
* UWB Radio Controllers
*/
struct uwb_dev *uwb_dev_get_by_devaddr(struct uwb_rc *rc,
const struct uwb_dev_addr *devaddr);
struct uwb_dev *uwb_dev_get_by_rc(struct uwb_dev *, struct uwb_rc *);
static inline void uwb_dev_get(struct uwb_dev *uwb_dev)
{
get_device(&uwb_dev->dev);
}
static inline void uwb_dev_put(struct uwb_dev *uwb_dev)
{
put_device(&uwb_dev->dev);
}
struct uwb_dev *uwb_dev_try_get(struct uwb_rc *rc, struct uwb_dev *uwb_dev);
/**
* Callback function for 'uwb_{dev,rc}_foreach()'.
*
* @dev: Linux device instance
* 'uwb_dev = container_of(dev, struct uwb_dev, dev)'
* @priv: Data passed by the caller to 'uwb_{dev,rc}_foreach()'.
*
* @returns: 0 to continue the iterations, any other val to stop
* iterating and return the value to the caller of
* _foreach().
*/
typedef int (*uwb_dev_for_each_f)(struct device *dev, void *priv);
int uwb_dev_for_each(struct uwb_rc *rc, uwb_dev_for_each_f func, void *priv);
struct uwb_rc *uwb_rc_alloc(void);
struct uwb_rc *uwb_rc_get_by_dev(const struct uwb_dev_addr *);
struct uwb_rc *uwb_rc_get_by_grandpa(const struct device *);
void uwb_rc_put(struct uwb_rc *rc);
typedef void (*uwb_rc_cmd_cb_f)(struct uwb_rc *rc, void *arg,
struct uwb_rceb *reply, ssize_t reply_size);
int uwb_rc_cmd_async(struct uwb_rc *rc, const char *cmd_name,
struct uwb_rccb *cmd, size_t cmd_size,
u8 expected_type, u16 expected_event,
uwb_rc_cmd_cb_f cb, void *arg);
ssize_t uwb_rc_cmd(struct uwb_rc *rc, const char *cmd_name,
struct uwb_rccb *cmd, size_t cmd_size,
struct uwb_rceb *reply, size_t reply_size);
ssize_t uwb_rc_vcmd(struct uwb_rc *rc, const char *cmd_name,
struct uwb_rccb *cmd, size_t cmd_size,
u8 expected_type, u16 expected_event,
struct uwb_rceb **preply);
int uwb_bg_joined(struct uwb_rc *rc);
size_t __uwb_addr_print(char *, size_t, const unsigned char *, int);
int uwb_rc_dev_addr_set(struct uwb_rc *, const struct uwb_dev_addr *);
int uwb_rc_dev_addr_get(struct uwb_rc *, struct uwb_dev_addr *);
int uwb_rc_mac_addr_set(struct uwb_rc *, const struct uwb_mac_addr *);
int uwb_rc_mac_addr_get(struct uwb_rc *, struct uwb_mac_addr *);
int __uwb_mac_addr_assigned_check(struct device *, void *);
int __uwb_dev_addr_assigned_check(struct device *, void *);
/* Print in @buf a pretty repr of @addr */
static inline size_t uwb_dev_addr_print(char *buf, size_t buf_size,
const struct uwb_dev_addr *addr)
{
return __uwb_addr_print(buf, buf_size, addr->data, 0);
}
/* Print in @buf a pretty repr of @addr */
static inline size_t uwb_mac_addr_print(char *buf, size_t buf_size,
const struct uwb_mac_addr *addr)
{
return __uwb_addr_print(buf, buf_size, addr->data, 1);
}
/* @returns 0 if device addresses @addr2 and @addr1 are equal */
static inline int uwb_dev_addr_cmp(const struct uwb_dev_addr *addr1,
const struct uwb_dev_addr *addr2)
{
return memcmp(addr1, addr2, sizeof(*addr1));
}
/* @returns 0 if MAC addresses @addr2 and @addr1 are equal */
static inline int uwb_mac_addr_cmp(const struct uwb_mac_addr *addr1,
const struct uwb_mac_addr *addr2)
{
return memcmp(addr1, addr2, sizeof(*addr1));
}
/* @returns !0 if a MAC @addr is a broadcast address */
static inline int uwb_mac_addr_bcast(const struct uwb_mac_addr *addr)
{
struct uwb_mac_addr bcast = {
.data = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }
};
return !uwb_mac_addr_cmp(addr, &bcast);
}
/* @returns !0 if a MAC @addr is all zeroes*/
static inline int uwb_mac_addr_unset(const struct uwb_mac_addr *addr)
{
struct uwb_mac_addr unset = {
.data = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
};
return !uwb_mac_addr_cmp(addr, &unset);
}
/* @returns !0 if the address is in use. */
static inline unsigned __uwb_dev_addr_assigned(struct uwb_rc *rc,
struct uwb_dev_addr *addr)
{
return uwb_dev_for_each(rc, __uwb_dev_addr_assigned_check, addr);
}
/*
* UWB Radio Controller API
*
* This API is used (in addition to the general API) to implement UWB
* Radio Controllers.
*/
void uwb_rc_init(struct uwb_rc *);
int uwb_rc_add(struct uwb_rc *, struct device *dev, void *rc_priv);
void uwb_rc_rm(struct uwb_rc *);
void uwb_rc_neh_grok(struct uwb_rc *, void *, size_t);
void uwb_rc_neh_error(struct uwb_rc *, int);
void uwb_rc_reset_all(struct uwb_rc *rc);
void uwb_rc_pre_reset(struct uwb_rc *rc);
void uwb_rc_post_reset(struct uwb_rc *rc);
/**
* uwb_rsv_is_owner - is the owner of this reservation the RC?
* @rsv: the reservation
*/
static inline bool uwb_rsv_is_owner(struct uwb_rsv *rsv)
{
return rsv->owner == &rsv->rc->uwb_dev;
}
/**
* Events generated by UWB that can be passed to any listeners
*
* Higher layers can register callback functions with the radio
* controller using uwb_notifs_register(). The radio controller
* maintains a list of all registered handlers and will notify all
* nodes when an event occurs.
*/
enum uwb_notifs {
UWB_NOTIF_BG_JOIN = 0, /* radio controller joined a beacon group */
UWB_NOTIF_BG_LEAVE = 1, /* radio controller left a beacon group */
UWB_NOTIF_ONAIR,
UWB_NOTIF_OFFAIR,
};
/* Callback function registered with UWB */
struct uwb_notifs_handler {
struct list_head list_node;
void (*cb)(void *, struct uwb_dev *, enum uwb_notifs);
void *data;
};
int uwb_notifs_register(struct uwb_rc *, struct uwb_notifs_handler *);
int uwb_notifs_deregister(struct uwb_rc *, struct uwb_notifs_handler *);
/**
* UWB radio controller Event Size Entry (for creating entry tables)
*
* WUSB and WHCI define events and notifications, and they might have
* fixed or variable size.
*
* Each event/notification has a size which is not necessarily known
* in advance based on the event code. As well, vendor specific
* events/notifications will have a size impossible to determine
* unless we know about the device's specific details.
*
* It was way too smart of the spec writers not to think that it would
* be impossible for a generic driver to skip over vendor specific
* events/notifications if there are no LENGTH fields in the HEADER of
* each message...the transaction size cannot be counted on as the
* spec does not forbid to pack more than one event in a single
* transaction.
*
* Thus, we guess sizes with tables (or for events, when you know the
* size ahead of time you can use uwb_rc_neh_extra_size*()). We
* register tables with the known events and their sizes, and then we
* traverse those tables. For those with variable length, we provide a
* way to lookup the size inside the event/notification's
* payload. This allows device-specific event size tables to be
* registered.
*
* @size: Size of the payload
*
* @offset: if != 0, at offset @offset-1 starts a field with a length
* that has to be added to @size. The format of the field is
* given by @type.
*
* @type: Type and length of the offset field. Most common is LE 16
* bits (that's why that is zero); others are there mostly to
* cover for bugs and weirdos.
*/
struct uwb_est_entry {
size_t size;
unsigned offset;
enum { UWB_EST_16 = 0, UWB_EST_8 = 1 } type;
};
int uwb_est_register(u8 type, u8 code_high, u16 vendor, u16 product,
const struct uwb_est_entry *, size_t entries);
int uwb_est_unregister(u8 type, u8 code_high, u16 vendor, u16 product,
const struct uwb_est_entry *, size_t entries);
ssize_t uwb_est_find_size(struct uwb_rc *rc, const struct uwb_rceb *rceb,
size_t len);
/* -- Misc */
enum {
EDC_MAX_ERRORS = 10,
EDC_ERROR_TIMEFRAME = HZ,
};
/* error density counter */
struct edc {
unsigned long timestart;
u16 errorcount;
};
static inline
void edc_init(struct edc *edc)
{
edc->timestart = jiffies;
}
/* Called when an error occured.
* This is way to determine if the number of acceptable errors per time
* period has been exceeded. It is not accurate as there are cases in which
* this scheme will not work, for example if there are periodic occurences
* of errors that straddle updates to the start time. This scheme is
* sufficient for our usage.
*
* @returns 1 if maximum acceptable errors per timeframe has been exceeded.
*/
static inline int edc_inc(struct edc *err_hist, u16 max_err, u16 timeframe)
{
unsigned long now;
now = jiffies;
if (now - err_hist->timestart > timeframe) {
err_hist->errorcount = 1;
err_hist->timestart = now;
} else if (++err_hist->errorcount > max_err) {
err_hist->errorcount = 0;
err_hist->timestart = now;
return 1;
}
return 0;
}
/* Information Element handling */
struct uwb_ie_hdr *uwb_ie_next(void **ptr, size_t *len);
int uwb_rc_ie_add(struct uwb_rc *uwb_rc, const struct uwb_ie_hdr *ies, size_t size);
int uwb_rc_ie_rm(struct uwb_rc *uwb_rc, enum uwb_ie element_id);
/*
* Transmission statistics
*
* UWB uses LQI and RSSI (one byte values) for reporting radio signal
* strength and line quality indication. We do quick and dirty
* averages of those. They are signed values, btw.
*
* For 8 bit quantities, we keep the min, the max, an accumulator
* (@sigma) and a # of samples. When @samples gets to 255, we compute
* the average (@sigma / @samples), place it in @sigma and reset
* @samples to 1 (so we use it as the first sample).
*
* Now, statistically speaking, probably I am kicking the kidneys of
* some books I have in my shelves collecting dust, but I just want to
* get an approx, not the Nobel.
*
* LOCKING: there is no locking per se, but we try to keep a lockless
* schema. Only _add_samples() modifies the values--as long as you
* have other locking on top that makes sure that no two calls of
* _add_sample() happen at the same time, then we are fine. Now, for
* resetting the values we just set @samples to 0 and that makes the
* next _add_sample() to start with defaults. Reading the values in
* _show() currently can race, so you need to make sure the calls are
* under the same lock that protects calls to _add_sample(). FIXME:
* currently unlocked (It is not ultraprecise but does the trick. Bite
* me).
*/
struct stats {
s8 min, max;
s16 sigma;
atomic_t samples;
};
static inline
void stats_init(struct stats *stats)
{
atomic_set(&stats->samples, 0);
wmb();
}
static inline
void stats_add_sample(struct stats *stats, s8 sample)
{
s8 min, max;
s16 sigma;
unsigned samples = atomic_read(&stats->samples);
if (samples == 0) { /* it was zero before, so we initialize */
min = 127;
max = -128;
sigma = 0;
} else {
min = stats->min;
max = stats->max;
sigma = stats->sigma;
}
if (sample < min) /* compute new values */
min = sample;
else if (sample > max)
max = sample;
sigma += sample;
stats->min = min; /* commit */
stats->max = max;
stats->sigma = sigma;
if (atomic_add_return(1, &stats->samples) > 255) {
/* wrapped around! reset */
stats->sigma = sigma / 256;
atomic_set(&stats->samples, 1);
}
}
static inline ssize_t stats_show(struct stats *stats, char *buf)
{
int min, max, avg;
int samples = atomic_read(&stats->samples);
if (samples == 0)
min = max = avg = 0;
else {
min = stats->min;
max = stats->max;
avg = stats->sigma / samples;
}
return scnprintf(buf, PAGE_SIZE, "%d %d %d\n", min, max, avg);
}
static inline ssize_t stats_store(struct stats *stats, const char *buf,
size_t size)
{
stats_init(stats);
return size;
}
#endif /* #ifndef __LINUX__UWB_H__ */
