iwl4965: add comments to rate scaling code
Add comments to rate scaling code.
Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965-rs.h b/drivers/net/wireless/iwlwifi/iwl-4965-rs.h
index 4259099..86f62d8 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965-rs.h
+++ b/drivers/net/wireless/iwlwifi/iwl-4965-rs.h
@@ -30,10 +30,10 @@
#include "iwl-4965.h"
struct iwl4965_rate_info {
- u8 plcp;
- u8 plcp_siso;
- u8 plcp_mimo;
- u8 ieee;
+ u8 plcp; /* uCode API: IWL_RATE_6M_PLCP, etc. */
+ u8 plcp_siso; /* uCode API: IWL_RATE_SISO_6M_PLCP, etc. */
+ u8 plcp_mimo; /* uCode API: IWL_RATE_MIMO_6M_PLCP, etc. */
+ u8 ieee; /* MAC header: IWL_RATE_6M_IEEE, etc. */
u8 prev_ieee; /* previous rate in IEEE speeds */
u8 next_ieee; /* next rate in IEEE speeds */
u8 prev_rs; /* previous rate used in rs algo */
@@ -42,6 +42,7 @@
u8 next_rs_tgg; /* next rate used in TGG rs algo */
};
+/* For driver (not uCode API) */
enum {
IWL_RATE_1M_INDEX = 0,
IWL_RATE_2M_INDEX,
@@ -83,6 +84,7 @@
#define IWL_RATE_5M_MASK (1<<IWL_RATE_5M_INDEX)
#define IWL_RATE_11M_MASK (1<<IWL_RATE_11M_INDEX)
+/* 4965 uCode API values for legacy bit rates, both OFDM and CCK */
enum {
IWL_RATE_6M_PLCP = 13,
IWL_RATE_9M_PLCP = 15,
@@ -99,7 +101,7 @@
IWL_RATE_11M_PLCP = 110,
};
-/* OFDM HT rate plcp */
+/* 4965 uCode API values for OFDM high-throughput (HT) bit rates */
enum {
IWL_RATE_SISO_6M_PLCP = 0,
IWL_RATE_SISO_12M_PLCP = 1,
@@ -121,6 +123,7 @@
IWL_RATE_MIMO_INVM_PLCP = IWL_RATE_SISO_INVM_PLCP,
};
+/* MAC header values for bit rates */
enum {
IWL_RATE_6M_IEEE = 12,
IWL_RATE_9M_IEEE = 18,
@@ -170,13 +173,8 @@
#define IWL_MIN_RSSI_VAL -100
#define IWL_MAX_RSSI_VAL 0
-#define IWL_LEGACY_SWITCH_ANTENNA 0
-#define IWL_LEGACY_SWITCH_SISO 1
-#define IWL_LEGACY_SWITCH_MIMO 2
-
-#define IWL_RS_GOOD_RATIO 12800
-
-#define IWL_ACTION_LIMIT 3
+/* These values specify how many Tx frame attempts before
+ * searching for a new modulation mode */
#define IWL_LEGACY_FAILURE_LIMIT 160
#define IWL_LEGACY_SUCCESS_LIMIT 480
#define IWL_LEGACY_TABLE_COUNT 160
@@ -185,29 +183,44 @@
#define IWL_NONE_LEGACY_SUCCESS_LIMIT 4500
#define IWL_NONE_LEGACY_TABLE_COUNT 1500
-#define IWL_RATE_SCALE_SWITCH (10880)
+/* Success ratio (ACKed / attempted tx frames) values (perfect is 128 * 100) */
+#define IWL_RS_GOOD_RATIO 12800 /* 100% */
+#define IWL_RATE_SCALE_SWITCH 10880 /* 85% */
+#define IWL_RATE_HIGH_TH 10880 /* 85% */
+#define IWL_RATE_INCREASE_TH 8960 /* 70% */
+#define IWL_RATE_DECREASE_TH 1920 /* 15% */
+/* possible actions when in legacy mode */
+#define IWL_LEGACY_SWITCH_ANTENNA 0
+#define IWL_LEGACY_SWITCH_SISO 1
+#define IWL_LEGACY_SWITCH_MIMO 2
+
+/* possible actions when in siso mode */
#define IWL_SISO_SWITCH_ANTENNA 0
#define IWL_SISO_SWITCH_MIMO 1
#define IWL_SISO_SWITCH_GI 2
+/* possible actions when in mimo mode */
#define IWL_MIMO_SWITCH_ANTENNA_A 0
#define IWL_MIMO_SWITCH_ANTENNA_B 1
#define IWL_MIMO_SWITCH_GI 2
-#define LQ_SIZE 2
+#define IWL_ACTION_LIMIT 3 /* # possible actions */
+
+#define LQ_SIZE 2 /* 2 mode tables: "Active" and "Search" */
extern const struct iwl4965_rate_info iwl4965_rates[IWL_RATE_COUNT];
enum iwl4965_table_type {
LQ_NONE,
- LQ_G,
+ LQ_G, /* legacy types */
LQ_A,
- LQ_SISO,
+ LQ_SISO, /* high-throughput types */
LQ_MIMO,
LQ_MAX,
};
+/* 4965 has 2 antennas/chains for Tx (but 3 for Rx) */
enum iwl4965_antenna_type {
ANT_NONE,
ANT_MAIN,