[source] mac80211: enable STBC and LDPC for VHT rates

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/?p=source.git;a=commitdiff;h=d002aee42c4894b19eab811f1b7c158d0d435ba7

commit d002aee42c4894b19eab811f1b7c158d0d435ba7
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Wed Jun 29 10:44:39 2016 +0200

    mac80211: enable STBC and LDPC for VHT rates
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 ...nstrel-Enable-STBC-and-LDPC-for-VHT-Rates.patch | 81 ++++++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/package/kernel/mac80211/patches/310-mac80211-minstrel-Enable-STBC-and-LDPC-for-VHT-Rates.patch b/package/kernel/mac80211/patches/310-mac80211-minstrel-Enable-STBC-and-LDPC-for-VHT-Rates.patch
new file mode 100644
index 0000000..25929c9
--- /dev/null
+++ b/package/kernel/mac80211/patches/310-mac80211-minstrel-Enable-STBC-and-LDPC-for-VHT-Rates.patch
@@ -0,0 +1,81 @@
+From: Chaitanya T K <chaitanya.mgit at gmail.com>
+Date: Mon, 27 Jun 2016 15:23:26 +0530
+Subject: [PATCH] mac80211: minstrel: Enable STBC and LDPC for VHT Rates
+
+If peer support reception of STBC and LDPC, enable them for better
+performance.
+
+Signed-off-by: Chaitanya TK <chaitanya.mgit at gmail.com>
+---
+
+--- a/include/linux/ieee80211.h
++++ b/include/linux/ieee80211.h
+@@ -1550,6 +1550,7 @@ struct ieee80211_vht_operation {
+ #define IEEE80211_VHT_CAP_RXSTBC_3				0x00000300
+ #define IEEE80211_VHT_CAP_RXSTBC_4				0x00000400
+ #define IEEE80211_VHT_CAP_RXSTBC_MASK				0x00000700
++#define IEEE80211_VHT_CAP_RXSTBC_SHIFT				8
+ #define IEEE80211_VHT_CAP_SU_BEAMFORMER_CAPABLE			0x00000800
+ #define IEEE80211_VHT_CAP_SU_BEAMFORMEE_CAPABLE			0x00001000
+ #define IEEE80211_VHT_CAP_BEAMFORMEE_STS_SHIFT                  13
+--- a/net/mac80211/rc80211_minstrel_ht.c
++++ b/net/mac80211/rc80211_minstrel_ht.c
+@@ -1166,13 +1166,14 @@ minstrel_ht_update_caps(void *priv, stru
+ 	struct minstrel_ht_sta_priv *msp = priv_sta;
+ 	struct minstrel_ht_sta *mi = &msp->ht;
+ 	struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
+-	u16 sta_cap = sta->ht_cap.cap;
++	u16 ht_cap = sta->ht_cap.cap;
+ 	struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
+ 	int use_vht;
+ 	int n_supported = 0;
+ 	int ack_dur;
+ 	int stbc;
+ 	int i;
++	bool ldpc = false;
+ 
+ 	/* fall back to the old minstrel for legacy stations */
+ 	if (!sta->ht_cap.ht_supported)
+@@ -1210,16 +1211,24 @@ minstrel_ht_update_caps(void *priv, stru
+ 	}
+ 	mi->sample_tries = 4;
+ 
+-	/* TODO tx_flags for vht - ATM the RC API is not fine-grained enough */
+ 	if (!use_vht) {
+-		stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
++		stbc = (ht_cap & IEEE80211_HT_CAP_RX_STBC) >>
+ 			IEEE80211_HT_CAP_RX_STBC_SHIFT;
+-		mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
+ 
+-		if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
+-			mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
++		if (ht_cap & IEEE80211_HT_CAP_LDPC_CODING)
++			ldpc = true;
++	} else {
++		stbc = (vht_cap->cap & IEEE80211_VHT_CAP_RXSTBC_MASK) >>
++			IEEE80211_VHT_CAP_RXSTBC_SHIFT;
++
++		if (vht_cap->cap & IEEE80211_VHT_CAP_RXLDPC)
++			ldpc = true;
+ 	}
+ 
++	mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
++	if (ldpc)
++		mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
++
+ 	for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
+ 		u32 gflags = minstrel_mcs_groups[i].flags;
+ 		int bw, nss;
+@@ -1232,10 +1241,10 @@ minstrel_ht_update_caps(void *priv, stru
+ 
+ 		if (gflags & IEEE80211_TX_RC_SHORT_GI) {
+ 			if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
+-				if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
++				if (!(ht_cap & IEEE80211_HT_CAP_SGI_40))
+ 					continue;
+ 			} else {
+-				if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
++				if (!(ht_cap & IEEE80211_HT_CAP_SGI_20))
+ 					continue;
+ 			}
+ 		}