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Subject[PATCH 5.10 055/563] wcn36xx: ensure pairing of init_scan/finish_scan and start_scan/end_scan
Date
From: Benjamin Li <benl@squareup.com>

[ Upstream commit 8f1ba8b0ee2679f0b3d22d2a5c1bc70c436fd872 ]

An SMD capture from the downstream prima driver on WCN3680B shows the
following command sequence for connected scans:

- init_scan_req
- start_scan_req, channel 1
- end_scan_req, channel 1
- start_scan_req, channel 2
- ...
- end_scan_req, channel 3
- finish_scan_req
- init_scan_req
- start_scan_req, channel 4
- ...
- end_scan_req, channel 6
- finish_scan_req
- ...
- end_scan_req, channel 165
- finish_scan_req

Upstream currently never calls wcn36xx_smd_end_scan, and in some cases[1]
still sends finish_scan_req twice in a row or before init_scan_req. A
typical connected scan looks like this:

- init_scan_req
- start_scan_req, channel 1
- finish_scan_req
- init_scan_req
- start_scan_req, channel 2
- ...
- start_scan_req, channel 165
- finish_scan_req
- finish_scan_req

This patch cleans up scanning so that init/finish and start/end are always
paired together and correctly nested.

- init_scan_req
- start_scan_req, channel 1
- end_scan_req, channel 1
- finish_scan_req
- init_scan_req
- start_scan_req, channel 2
- end_scan_req, channel 2
- ...
- start_scan_req, channel 165
- end_scan_req, channel 165
- finish_scan_req

Note that upstream will not do batching of 3 active-probe scans before
returning to the operating channel, and this patch does not change that.
To match downstream in this aspect, adjust IEEE80211_PROBE_DELAY and/or
the 125ms max off-channel time in ieee80211_scan_state_decision.

[1]: commit d195d7aac09b ("wcn36xx: Ensure finish scan is not requested
before start scan") addressed one case of finish_scan_req being sent
without a preceding init_scan_req (the case of the operating channel
coinciding with the first scan channel); two other cases are:
1) if SW scan is started and aborted immediately, without scanning any
channels, we send a finish_scan_req without ever sending init_scan_req,
and
2) as SW scan logic always returns us to the operating channel before
calling wcn36xx_sw_scan_complete, finish_scan_req is always sent twice
at the end of a SW scan

Fixes: 8e84c2582169 ("wcn36xx: mac80211 driver for Qualcomm WCN3660/WCN3680 hardware")
Signed-off-by: Benjamin Li <benl@squareup.com>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211027170306.555535-4-benl@squareup.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/ath/wcn36xx/main.c | 34 +++++++++++++++++-----
drivers/net/wireless/ath/wcn36xx/smd.c | 4 +++
drivers/net/wireless/ath/wcn36xx/wcn36xx.h | 1 +
3 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/ath/wcn36xx/main.c b/drivers/net/wireless/ath/wcn36xx/main.c
index 629ddfd74da1a..9aaf6f7473333 100644
--- a/drivers/net/wireless/ath/wcn36xx/main.c
+++ b/drivers/net/wireless/ath/wcn36xx/main.c
@@ -397,6 +397,7 @@ static void wcn36xx_change_opchannel(struct wcn36xx *wcn, int ch)
static int wcn36xx_config(struct ieee80211_hw *hw, u32 changed)
{
struct wcn36xx *wcn = hw->priv;
+ int ret;

wcn36xx_dbg(WCN36XX_DBG_MAC, "mac config changed 0x%08x\n", changed);

@@ -412,17 +413,31 @@ static int wcn36xx_config(struct ieee80211_hw *hw, u32 changed)
* want to receive/transmit regular data packets, then
* simply stop the scan session and exit PS mode.
*/
- wcn36xx_smd_finish_scan(wcn, HAL_SYS_MODE_SCAN,
- wcn->sw_scan_vif);
- wcn->sw_scan_channel = 0;
+ if (wcn->sw_scan_channel)
+ wcn36xx_smd_end_scan(wcn, wcn->sw_scan_channel);
+ if (wcn->sw_scan_init) {
+ wcn36xx_smd_finish_scan(wcn, HAL_SYS_MODE_SCAN,
+ wcn->sw_scan_vif);
+ }
} else if (wcn->sw_scan) {
/* A scan is ongoing, do not change the operating
* channel, but start a scan session on the channel.
*/
- wcn36xx_smd_init_scan(wcn, HAL_SYS_MODE_SCAN,
- wcn->sw_scan_vif);
+ if (wcn->sw_scan_channel)
+ wcn36xx_smd_end_scan(wcn, wcn->sw_scan_channel);
+ if (!wcn->sw_scan_init) {
+ /* This can fail if we are unable to notify the
+ * operating channel.
+ */
+ ret = wcn36xx_smd_init_scan(wcn,
+ HAL_SYS_MODE_SCAN,
+ wcn->sw_scan_vif);
+ if (ret) {
+ mutex_unlock(&wcn->conf_mutex);
+ return -EIO;
+ }
+ }
wcn36xx_smd_start_scan(wcn, ch);
- wcn->sw_scan_channel = ch;
} else {
wcn36xx_change_opchannel(wcn, ch);
}
@@ -709,7 +724,12 @@ static void wcn36xx_sw_scan_complete(struct ieee80211_hw *hw,
struct wcn36xx *wcn = hw->priv;

/* ensure that any scan session is finished */
- wcn36xx_smd_finish_scan(wcn, HAL_SYS_MODE_SCAN, wcn->sw_scan_vif);
+ if (wcn->sw_scan_channel)
+ wcn36xx_smd_end_scan(wcn, wcn->sw_scan_channel);
+ if (wcn->sw_scan_init) {
+ wcn36xx_smd_finish_scan(wcn, HAL_SYS_MODE_SCAN,
+ wcn->sw_scan_vif);
+ }
wcn->sw_scan = false;
wcn->sw_scan_opchannel = 0;
}
diff --git a/drivers/net/wireless/ath/wcn36xx/smd.c b/drivers/net/wireless/ath/wcn36xx/smd.c
index 3793907ace92e..ad312e17f7a3c 100644
--- a/drivers/net/wireless/ath/wcn36xx/smd.c
+++ b/drivers/net/wireless/ath/wcn36xx/smd.c
@@ -730,6 +730,7 @@ int wcn36xx_smd_init_scan(struct wcn36xx *wcn, enum wcn36xx_hal_sys_mode mode,
wcn36xx_err("hal_init_scan response failed err=%d\n", ret);
goto out;
}
+ wcn->sw_scan_init = true;
out:
mutex_unlock(&wcn->hal_mutex);
return ret;
@@ -760,6 +761,7 @@ int wcn36xx_smd_start_scan(struct wcn36xx *wcn, u8 scan_channel)
wcn36xx_err("hal_start_scan response failed err=%d\n", ret);
goto out;
}
+ wcn->sw_scan_channel = scan_channel;
out:
mutex_unlock(&wcn->hal_mutex);
return ret;
@@ -790,6 +792,7 @@ int wcn36xx_smd_end_scan(struct wcn36xx *wcn, u8 scan_channel)
wcn36xx_err("hal_end_scan response failed err=%d\n", ret);
goto out;
}
+ wcn->sw_scan_channel = 0;
out:
mutex_unlock(&wcn->hal_mutex);
return ret;
@@ -831,6 +834,7 @@ int wcn36xx_smd_finish_scan(struct wcn36xx *wcn,
wcn36xx_err("hal_finish_scan response failed err=%d\n", ret);
goto out;
}
+ wcn->sw_scan_init = false;
out:
mutex_unlock(&wcn->hal_mutex);
return ret;
diff --git a/drivers/net/wireless/ath/wcn36xx/wcn36xx.h b/drivers/net/wireless/ath/wcn36xx/wcn36xx.h
index 9b4dee2fc6483..5c40d0bdee245 100644
--- a/drivers/net/wireless/ath/wcn36xx/wcn36xx.h
+++ b/drivers/net/wireless/ath/wcn36xx/wcn36xx.h
@@ -231,6 +231,7 @@ struct wcn36xx {
struct cfg80211_scan_request *scan_req;
bool sw_scan;
u8 sw_scan_opchannel;
+ bool sw_scan_init;
u8 sw_scan_channel;
struct ieee80211_vif *sw_scan_vif;
struct mutex scan_lock;
--
2.34.1


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