ath10k: handle cycle counter wraparound

When QCA988X cycle counter HW register wraps
around it resets to 0x7fffffff instead of 0. All
other cycle counter related registers are divided
by 2 so they never wraparound themselves. QCA61X4
has a uniform CC and it wraparounds in a regular
fashion though.

Worst case wraparound time is approx 24 seconds
(2**31 / 88MHz). Since scan channel visit times
are max 5 seconds (offchannel case) it is
guaranteed there's been at most 1 wraparound and
it is possible to compute survey active time
value. It is, however, impossible to determine the
point at which Rx Clear Count has been divided by
two so it is not reported upon wraparound.

This fixes some occasional incorrect survey data
on QCA988X as some channels (depending on how/when
scan/offchannel requests were requested) would
have approx 24 sec active time which wasn't
actually the case.

This should improve hostapd ACS a little bit.

Reported-by: Srinivasa Duvvuri <sduvvuri@chromium.org>
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index bcccae19325d8f77da713a37956514ee5f97c1b9..684d460d79b725227be43babb62f9f2344e9099d 100644 (file)
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -48,6 +48,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
                .name = "qca988x hw2.0",
                .patch_load_addr = QCA988X_HW_2_0_PATCH_LOAD_ADDR,
                .uart_pin = 7,
+               .has_shifted_cc_wraparound = true,
                .fw = {
                        .dir = QCA988X_HW_2_0_FW_DIR,
                        .fw = QCA988X_HW_2_0_FW_FILE,

diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
index 70fcdc9c27587593046f1aeab8fd3b68b2d74364..5a648e92ee99cf6e256584e79c96c89f5af0058e 100644 (file)
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -577,6 +577,13 @@ struct ath10k {
                u32 patch_load_addr;
                int uart_pin;
 
+               /* This is true if given HW chip has a quirky Cycle Counter
+                * wraparound which resets to 0x7fffffff instead of 0. All
+                * other CC related counters (e.g. Rx Clear Count) are divided
+                * by 2 so they never wraparound themselves.
+                */
+               bool has_shifted_cc_wraparound;
+
                struct ath10k_hw_params_fw {
                        const char *dir;
                        const char *fw;

diff --git a/drivers/net/wireless/ath/ath10k/hw.c b/drivers/net/wireless/ath/ath10k/hw.c
index 839a8791fb9e4a53d05e29e991b6d33510520044..5997f00afe3b43b677f1718a64a213090c969d92 100644 (file)
--- a/drivers/net/wireless/ath/ath10k/hw.c
+++ b/drivers/net/wireless/ath/ath10k/hw.c
@@ -15,6 +15,7 @@
  */
 
 #include <linux/types.h>
+#include "core.h"
 #include "hw.h"
 
 const struct ath10k_hw_regs qca988x_regs = {
@@ -56,3 +57,23 @@ const struct ath10k_hw_regs qca6174_regs = {
        .soc_chip_id_address                    = 0x000f0,
        .scratch_3_address                      = 0x0028,
 };
+
+void ath10k_hw_fill_survey_time(struct ath10k *ar, struct survey_info *survey,
+                               u32 cc, u32 rcc, u32 cc_prev, u32 rcc_prev)
+{
+       u32 cc_fix = 0;
+
+       survey->filled |= SURVEY_INFO_TIME |
+                         SURVEY_INFO_TIME_BUSY;
+
+       if (ar->hw_params.has_shifted_cc_wraparound && cc < cc_prev) {
+               cc_fix = 0x7fffffff;
+               survey->filled &= ~SURVEY_INFO_TIME_BUSY;
+       }
+
+       cc -= cc_prev - cc_fix;
+       rcc -= rcc_prev;
+
+       survey->time = CCNT_TO_MSEC(cc);
+       survey->time_busy = CCNT_TO_MSEC(rcc);
+}

diff --git a/drivers/net/wireless/ath/ath10k/hw.h b/drivers/net/wireless/ath/ath10k/hw.h
index 372f0b8c96f52a9ded23df0a6e3d9882ed68c89d..85cca29375fee8f08ab09975c31cc3130194176e 100644 (file)
--- a/drivers/net/wireless/ath/ath10k/hw.h
+++ b/drivers/net/wireless/ath/ath10k/hw.h
@@ -169,6 +169,9 @@ struct ath10k_hw_regs {
 extern const struct ath10k_hw_regs qca988x_regs;
 extern const struct ath10k_hw_regs qca6174_regs;
 
+void ath10k_hw_fill_survey_time(struct ath10k *ar, struct survey_info *survey,
+                               u32 cc, u32 rcc, u32 cc_prev, u32 rcc_prev);
+
 #define QCA_REV_988X(ar) ((ar)->hw_rev == ATH10K_HW_QCA988X)
 #define QCA_REV_6174(ar) ((ar)->hw_rev == ATH10K_HW_QCA6174)
 

diff --git a/drivers/net/wireless/ath/ath10k/wmi.c b/drivers/net/wireless/ath/ath10k/wmi.c
index 43caabf5b02548cd8aa22844e0cbd049a48072af..70e6efa2c071265c2d3ffbdeb204e88ace71707e 100644 (file)
--- a/drivers/net/wireless/ath/ath10k/wmi.c
+++ b/drivers/net/wireless/ath/ath10k/wmi.c
@@ -27,6 +27,7 @@
 #include "testmode.h"
 #include "wmi-ops.h"
 #include "p2p.h"
+#include "hw.h"
 
 /* MAIN WMI cmd track */
 static struct wmi_cmd_map wmi_cmd_map = {
@@ -1640,16 +1641,16 @@ void ath10k_wmi_event_chan_info(struct ath10k *ar, struct sk_buff *skb)
                 * visited channel. The reported cycle count is global
                 * and per-channel cycle count must be calculated */
 
-               cycle_count -= ar->survey_last_cycle_count;
-               rx_clear_count -= ar->survey_last_rx_clear_count;
-
                survey = &ar->survey[idx];
-               survey->time = CCNT_TO_MSEC(cycle_count);
-               survey->time_busy = CCNT_TO_MSEC(rx_clear_count);
                survey->noise = noise_floor;
-               survey->filled = SURVEY_INFO_TIME |
-                                SURVEY_INFO_TIME_BUSY |
-                                SURVEY_INFO_NOISE_DBM;
+               survey->filled = SURVEY_INFO_NOISE_DBM;
+
+               ath10k_hw_fill_survey_time(ar,
+                                          survey,
+                                          cycle_count,
+                                          rx_clear_count,
+                                          ar->survey_last_cycle_count,
+                                          ar->survey_last_rx_clear_count);
        }
 
        ar->survey_last_rx_clear_count = rx_clear_count;