diff options
Diffstat (limited to 'drivers/net/wireless/intel/iwlwifi/iwl-utils.c')
| -rw-r--r-- | drivers/net/wireless/intel/iwlwifi/iwl-utils.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-utils.c b/drivers/net/wireless/intel/iwlwifi/iwl-utils.c new file mode 100644 index 000000000000..d503544fda40 --- /dev/null +++ b/drivers/net/wireless/intel/iwlwifi/iwl-utils.c @@ -0,0 +1,195 @@ +/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */ +/* + * Copyright (C) 2024-2025 Intel Corporation + */ +#include <net/gso.h> +#include <linux/ieee80211.h> +#include <net/ip.h> + +#include "iwl-drv.h" +#include "iwl-utils.h" + +#ifdef CONFIG_INET +int iwl_tx_tso_segment(struct sk_buff *skb, unsigned int num_subframes, + netdev_features_t netdev_flags, + struct sk_buff_head *mpdus_skbs) +{ + struct sk_buff *tmp, *next; + struct ieee80211_hdr *hdr = (void *)skb->data; + char cb[sizeof(skb->cb)]; + u16 i = 0; + unsigned int tcp_payload_len; + unsigned int mss = skb_shinfo(skb)->gso_size; + bool ipv4 = (skb->protocol == htons(ETH_P_IP)); + bool qos = ieee80211_is_data_qos(hdr->frame_control); + u16 ip_base_id = ipv4 ? ntohs(ip_hdr(skb)->id) : 0; + + skb_shinfo(skb)->gso_size = num_subframes * mss; + memcpy(cb, skb->cb, sizeof(cb)); + + next = skb_gso_segment(skb, netdev_flags); + skb_shinfo(skb)->gso_size = mss; + skb_shinfo(skb)->gso_type = ipv4 ? SKB_GSO_TCPV4 : SKB_GSO_TCPV6; + + if (IS_ERR(next) && PTR_ERR(next) == -ENOMEM) + return -ENOMEM; + + if (WARN_ONCE(IS_ERR(next), + "skb_gso_segment error: %d\n", (int)PTR_ERR(next))) + return PTR_ERR(next); + + if (next) + consume_skb(skb); + + skb_list_walk_safe(next, tmp, next) { + memcpy(tmp->cb, cb, sizeof(tmp->cb)); + /* + * Compute the length of all the data added for the A-MSDU. + * This will be used to compute the length to write in the TX + * command. We have: SNAP + IP + TCP for n -1 subframes and + * ETH header for n subframes. + */ + tcp_payload_len = skb_tail_pointer(tmp) - + skb_transport_header(tmp) - + tcp_hdrlen(tmp) + tmp->data_len; + + if (ipv4) + ip_hdr(tmp)->id = htons(ip_base_id + i * num_subframes); + + if (tcp_payload_len > mss) { + skb_shinfo(tmp)->gso_size = mss; + skb_shinfo(tmp)->gso_type = ipv4 ? SKB_GSO_TCPV4 : + SKB_GSO_TCPV6; + } else { + if (qos) { + u8 *qc; + + if (ipv4) + ip_send_check(ip_hdr(tmp)); + + qc = ieee80211_get_qos_ctl((void *)tmp->data); + *qc &= ~IEEE80211_QOS_CTL_A_MSDU_PRESENT; + } + skb_shinfo(tmp)->gso_size = 0; + } + + skb_mark_not_on_list(tmp); + __skb_queue_tail(mpdus_skbs, tmp); + i++; + } + + return 0; +} +IWL_EXPORT_SYMBOL(iwl_tx_tso_segment); +#endif /* CONFIG_INET */ + +static u32 iwl_div_by_db(u32 value, u8 db) +{ + /* + * 2^32 * 10**(i / 10) for i = [1, 10], skipping 0 and simply stopping + * at 10 dB and looping instead of using a much larger table. + * + * Using 64 bit math is overkill, but means the helper does not require + * a limit on the input range. + */ + static const u32 db_to_val[] = { + 0xcb59185e, 0xa1866ba8, 0x804dce7a, 0x65ea59fe, 0x50f44d89, + 0x404de61f, 0x331426af, 0x2892c18b, 0x203a7e5b, 0x1999999a, + }; + + while (value && db > 0) { + u8 change = min_t(u8, db, ARRAY_SIZE(db_to_val)); + + value = (((u64)value) * db_to_val[change - 1]) >> 32; + + db -= change; + } + + return value; +} + +s8 iwl_average_neg_dbm(const u8 *neg_dbm_values, u8 len) +{ + int average_magnitude; + u32 average_factor; + int sum_magnitude = -128; + u32 sum_factor = 0; + int i, count = 0; + + /* + * To properly average the decibel values (signal values given in dBm) + * we need to do the math in linear space. Doing a linear average of + * dB (dBm) values is a bit annoying though due to the large range of + * at least -10 to -110 dBm that will not fit into a 32 bit integer. + * + * A 64 bit integer should be sufficient, but then we still have the + * problem that there are no directly usable utility functions + * available. + * + * So, lets not deal with that and instead do much of the calculation + * with a 16.16 fixed point integer along with a base in dBm. 16.16 bit + * gives us plenty of head-room for adding up a few values and even + * doing some math on it. And the tail should be accurate enough too + * (1/2^16 is somewhere around -48 dB, so effectively zero). + * + * i.e. the real value of sum is: + * sum = sum_factor / 2^16 * 10^(sum_magnitude / 10) mW + * + * However, that does mean we need to be able to bring two values to + * a common base, so we need a helper for that. + * + * Note that this function takes an input with unsigned negative dBm + * values but returns a signed dBm (i.e. a negative value). + */ + + for (i = 0; i < len; i++) { + int val_magnitude; + u32 val_factor; + + /* Assume invalid */ + if (neg_dbm_values[i] == 0xff) + continue; + + val_factor = 0x10000; + val_magnitude = -neg_dbm_values[i]; + + if (val_magnitude <= sum_magnitude) { + u8 div_db = sum_magnitude - val_magnitude; + + val_factor = iwl_div_by_db(val_factor, div_db); + val_magnitude = sum_magnitude; + } else { + u8 div_db = val_magnitude - sum_magnitude; + + sum_factor = iwl_div_by_db(sum_factor, div_db); + sum_magnitude = val_magnitude; + } + + sum_factor += val_factor; + count++; + } + + /* No valid noise measurement, return a very high noise level */ + if (count == 0) + return 0; + + average_magnitude = sum_magnitude; + average_factor = sum_factor / count; + + /* + * average_factor will be a number smaller than 1.0 (0x10000) at this + * point. What we need to do now is to adjust average_magnitude so that + * average_factor is between -0.5 dB and 0.5 dB. + * + * Just do -1 dB steps and find the point where + * -0.5 dB * -i dB = 0x10000 * 10^(-0.5/10) / i dB + * = div_by_db(0xe429, i) + * is smaller than average_factor. + */ + for (i = 0; average_factor < iwl_div_by_db(0xe429, i); i++) { + /* nothing */ + } + + return clamp(average_magnitude - i, -128, 0); +} +IWL_EXPORT_SYMBOL(iwl_average_neg_dbm); |