drivers/net/wireless/intel/iwlegacy/4965-calib.c

Source file repositories/reference/linux-study-clean/drivers/net/wireless/intel/iwlegacy/4965-calib.c

File Facts

System
Linux kernel
Corpus path
drivers/net/wireless/intel/iwlegacy/4965-calib.c
Extension
.c
Size
30734 bytes
Lines
935
Domain
Driver Families
Bucket
drivers/net
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct stats_general_data {
	u32 beacon_silence_rssi_a;
	u32 beacon_silence_rssi_b;
	u32 beacon_silence_rssi_c;
	u32 beacon_energy_a;
	u32 beacon_energy_b;
	u32 beacon_energy_c;
};

/*****************************************************************************
 * RUNTIME calibrations framework
 *****************************************************************************/

/* "false alarms" are signals that our DSP tries to lock onto,
 *   but then determines that they are either noise, or transmissions
 *   from a distant wireless network (also "noise", really) that get
 *   "stepped on" by stronger transmissions within our own network.
 * This algorithm attempts to set a sensitivity level that is high
 *   enough to receive all of our own network traffic, but not so
 *   high that our DSP gets too busy trying to lock onto non-network
 *   activity/noise. */
static int
il4965_sens_energy_cck(struct il_priv *il, u32 norm_fa, u32 rx_enable_time,
		       struct stats_general_data *rx_info)
{
	u32 max_nrg_cck = 0;
	int i = 0;
	u8 max_silence_rssi = 0;
	u32 silence_ref = 0;
	u8 silence_rssi_a = 0;
	u8 silence_rssi_b = 0;
	u8 silence_rssi_c = 0;
	u32 val;

	/* "false_alarms" values below are cross-multiplications to assess the
	 *   numbers of false alarms within the measured period of actual Rx
	 *   (Rx is off when we're txing), vs the min/max expected false alarms
	 *   (some should be expected if rx is sensitive enough) in a
	 *   hypothetical listening period of 200 time units (TU), 204.8 msec:
	 *
	 * MIN_FA/fixed-time < false_alarms/actual-rx-time < MAX_FA/beacon-time
	 *
	 * */
	u32 false_alarms = norm_fa * 200 * 1024;
	u32 max_false_alarms = MAX_FA_CCK * rx_enable_time;
	u32 min_false_alarms = MIN_FA_CCK * rx_enable_time;
	struct il_sensitivity_data *data = NULL;
	const struct il_sensitivity_ranges *ranges = il->hw_params.sens;

	data = &(il->sensitivity_data);

	data->nrg_auto_corr_silence_diff = 0;

	/* Find max silence rssi among all 3 receivers.
	 * This is background noise, which may include transmissions from other
	 *    networks, measured during silence before our network's beacon */
	silence_rssi_a =
	    (u8) ((rx_info->beacon_silence_rssi_a & ALL_BAND_FILTER) >> 8);
	silence_rssi_b =
	    (u8) ((rx_info->beacon_silence_rssi_b & ALL_BAND_FILTER) >> 8);
	silence_rssi_c =
	    (u8) ((rx_info->beacon_silence_rssi_c & ALL_BAND_FILTER) >> 8);

	val = max(silence_rssi_b, silence_rssi_c);
	max_silence_rssi = max(silence_rssi_a, (u8) val);

	/* Store silence rssi in 20-beacon history table */
	data->nrg_silence_rssi[data->nrg_silence_idx] = max_silence_rssi;
	data->nrg_silence_idx++;
	if (data->nrg_silence_idx >= NRG_NUM_PREV_STAT_L)
		data->nrg_silence_idx = 0;

	/* Find max silence rssi across 20 beacon history */
	for (i = 0; i < NRG_NUM_PREV_STAT_L; i++) {
		val = data->nrg_silence_rssi[i];
		silence_ref = max(silence_ref, val);
	}
	D_CALIB("silence a %u, b %u, c %u, 20-bcn max %u\n", silence_rssi_a,
		silence_rssi_b, silence_rssi_c, silence_ref);

	/* Find max rx energy (min value!) among all 3 receivers,
	 *   measured during beacon frame.
	 * Save it in 10-beacon history table. */
	i = data->nrg_energy_idx;
	val = min(rx_info->beacon_energy_b, rx_info->beacon_energy_c);
	data->nrg_value[i] = min(rx_info->beacon_energy_a, val);

	data->nrg_energy_idx++;
	if (data->nrg_energy_idx >= 10)
		data->nrg_energy_idx = 0;

Annotation

Implementation Notes