Re: [ath9k-devel] [PATCH v2 1/3] mac80211: add STBC flag for radiotap

[Johannes Berg]

On Thu, 2013-05-23 at 09:17 +0200, Oleksij Rempel wrote:
 revision:
 - v2. set HAVE_STBC only if it is present.
   do not set STBC flag on TX packets.

Please don't include changes *inside* the changelog. Also, an actual
commit message would be nice.

johannes

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[ath9k-devel] [PATCH v3 1/3] mac80211: add STBC flag for radiotap

[Oleksij Rempel]

Some chips can tell us if received frame was
encoded with STBC or not. To make this information available
in user space we can use updated radiotap specification:
http://www.radiotap.org/defined-fields/MCS

This patch add HAVE_STBC flag and provide number
of STBC encoded spatial streams (Nss).

Signed-off-by: Oleksij Rempel li...@rempel-privat.de
---
 include/net/ieee80211_radiotap.h |  7 +++
 include/net/mac80211.h   |  4 
 net/mac80211/rx.c| 13 -
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/include/net/ieee80211_radiotap.h b/include/net/ieee80211_radiotap.h
index c399963..c6d07cb 100644
--- a/include/net/ieee80211_radiotap.h
+++ b/include/net/ieee80211_radiotap.h
@@ -269,6 +269,7 @@ enum ieee80211_radiotap_type {
 #define IEEE80211_RADIOTAP_MCS_HAVE_GI 0x04
 #define IEEE80211_RADIOTAP_MCS_HAVE_FMT0x08
 #define IEEE80211_RADIOTAP_MCS_HAVE_FEC0x10
+#define IEEE80211_RADIOTAP_MCS_HAVE_STBC   0x20
 
 #define IEEE80211_RADIOTAP_MCS_BW_MASK 0x03
 #defineIEEE80211_RADIOTAP_MCS_BW_200
@@ -278,6 +279,12 @@ enum ieee80211_radiotap_type {
 #define IEEE80211_RADIOTAP_MCS_SGI 0x04
 #define IEEE80211_RADIOTAP_MCS_FMT_GF  0x08
 #define IEEE80211_RADIOTAP_MCS_FEC_LDPC0x10
+#define IEEE80211_RADIOTAP_MCS_STBC_MASK   0x60
+#defineIEEE80211_RADIOTAP_MCS_STBC_1   1
+#defineIEEE80211_RADIOTAP_MCS_STBC_2   2
+#defineIEEE80211_RADIOTAP_MCS_STBC_3   3
+
+#define IEEE80211_RADIOTAP_MCS_STBC_SHIFT  5
 
 /* For IEEE80211_RADIOTAP_AMPDU_STATUS */
 #define IEEE80211_RADIOTAP_AMPDU_REPORT_ZEROLEN0x0001
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 885898a..16705a9 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -805,6 +805,7 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info 
*info)
  * on this subframe
  * @RX_FLAG_AMPDU_DELIM_CRC_KNOWN: The delimiter CRC field is known (the CRC
  * is stored in the @ampdu_delimiter_crc field)
+ * @RX_FLAG_STBC_MASK: STBC 2 bit bitmask. 1 - Nss=1, 2 - Nss=2, 3 - Nss=3
  */
 enum mac80211_rx_flags {
RX_FLAG_MMIC_ERROR  = BIT(0),
@@ -832,8 +833,11 @@ enum mac80211_rx_flags {
RX_FLAG_80MHZ   = BIT(23),
RX_FLAG_80P80MHZ= BIT(24),
RX_FLAG_160MHZ  = BIT(25),
+   RX_FLAG_STBC_MASK   = BIT(26) | BIT(27),
 };
 
+#define RX_FLAG_STBC_SHIFT 26
+
 /**
  * struct ieee80211_rx_status - receive status
  *
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 8e29526..db7c68a 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -258,8 +258,16 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local 
*local,
pos += 2;
 
if (status-flag  RX_FLAG_HT) {
+   unsigned int stbc = status-flag  RX_FLAG_STBC_MASK;
rthdr-it_present |= cpu_to_le32(1  IEEE80211_RADIOTAP_MCS);
-   *pos++ = local-hw.radiotap_mcs_details;
+
+   /* MCS known field */
+   *pos = local-hw.radiotap_mcs_details;
+   if (stbc)
+   *pos |= IEEE80211_RADIOTAP_MCS_HAVE_STBC;
+   *pos++;
+
+   /* MCS flags field */
*pos = 0;
if (status-flag  RX_FLAG_SHORT_GI)
*pos |= IEEE80211_RADIOTAP_MCS_SGI;
@@ -267,6 +275,9 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local 
*local,
*pos |= IEEE80211_RADIOTAP_MCS_BW_40;
if (status-flag  RX_FLAG_HT_GF)
*pos |= IEEE80211_RADIOTAP_MCS_FMT_GF;
+   if (stbc)
+   *pos |= (stbc  RX_FLAG_STBC_SHIFT)
+IEEE80211_RADIOTAP_MCS_STBC_SHIFT;
pos++;
*pos++ = status-rate_idx;
}
-- 
1.8.1.2

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Re: [ath9k-devel] [PATCH v3 1/3] mac80211: add STBC flag for radiotap

[Johannes Berg]

On Thu, 2013-05-23 at 16:11 +0200, Oleksij Rempel wrote:

 - *pos++ = local-hw.radiotap_mcs_details;
 +
 + /* MCS known field */
 + *pos = local-hw.radiotap_mcs_details;
 + if (stbc)
 + *pos |= IEEE80211_RADIOTAP_MCS_HAVE_STBC;

I think you shouldn't make this change, and the driver should include
the HAVE_STBC flag in the hw.radiotap_mcs_details. I actually thought of
this approach as well, but now just realized that this means that if the
driver _knows_ that a certain frame was received w/o STBC, this
knowledge cannot be transferred to the user, which would be a loss of
information.

 +   if (stbc)
 +   *pos |= (stbc  RX_FLAG_STBC_SHIFT)
 +   
 IEEE80211_RADIOTAP_MCS_STBC_SHIFT;

No need for the if() here, OR'ing in 0 doesn't do anything.

johannes

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[ath9k-devel] modifying priority of UDP packets

[abhinav narain]

Hi all,
I wanted to modify the priority of one of specific UDP frames generated by
my specific application,
to be send on VI queue.
Can someone please tell, which files should I look into in compat-wireless
folder ?
-
Abhinav
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