[PATCH] wcn36xx: Add hardware scan offload support

[Bjorn Andersson]

On Fri 08 Dec 01:35 PST 2017, Loic Poulain wrote:

> Current hw_scan implementation does not trigger offloaded
> hardware scan and seems to only put the device in a kind of
> listening mode (beacon/probe-response) for software scan.
> Since no probe request are generated by the software, current
> scanning method is similar to a passive scan.
> 
> This patch introduces support for 'true' hardware offloaded scan.
> Hardware scan is configured and started via the start-scan-offload
> firmware message. Once scan has been completed a scan indicator
> message is received from firmware.
> 
> Moreover, this patch includes support for directed probe-request,
> allowing connection with hidden APs. It also fixes scan issues with
> band-steering AP which are not 'visible' with passive scan (due to
> hidden ssid in beacons).
> 

I'm puzzled to why I didn't see this when I dumped the control channel
that lead up to the initial hw_scan patch. But this looks good and with
a related locking issue fixed this seems to work well.

Acked-by: Bjorn Andersson <bjorn.andersson at linaro.org>

> diff --git a/drivers/net/wireless/ath/wcn36xx/smd.c b/drivers/net/wireless/ath/wcn36xx/smd.c
[..]
> +static int wcn36xx_smd_hw_scan_ind(struct wcn36xx *wcn, void *buf, size_t len)
> +{
> +	struct wcn36xx_hal_scan_offload_ind *rsp = buf;
> +	struct cfg80211_scan_info scan_info = {};
> +
> +	if (len != sizeof(*rsp)) {
> +		wcn36xx_warn("Corrupted delete scan indication\n");
> +		return -EIO;
> +	}
> +
> +	wcn36xx_dbg(WCN36XX_DBG_HAL, "scan indication (type %x)", rsp->type);
> +
> +	switch (rsp->type) {
> +	case WCN36XX_HAL_SCAN_IND_FAILED:
> +		scan_info.aborted = true;
> +	case WCN36XX_HAL_SCAN_IND_COMPLETED:
> +		mutex_lock(&wcn->scan_lock);

Grabbing this mutex with DEBUG_ATOMIC_SLEEP causes issues, but that's
because the locking in ind_smd_work() is to excessive. Will reply with a
fix for this.

> +		wcn->scan_req = NULL;
> +		mutex_unlock(&wcn->scan_lock);
> +		ieee80211_scan_completed(wcn->hw, &scan_info);
> +		break;

Regards,
Bjorn