Message-ID: <efa997a0-f1a1-c09f-801c-80617e2f51dc@pengutronix.de>
Date:   Thu, 14 Jul 2022 17:22:11 +0200
From:   Ahmad Fatoum <a.fatoum@...gutronix.de>
To:     Alvin Šipraga <alvin@...s.dk>,
        Kalle Valo <kvalo@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Arend van Spriel <aspriel@...il.com>,
        Franky Lin <franky.lin@...adcom.com>,
        Hante Meuleman <hante.meuleman@...adcom.com>,
        van Spriel <arend@...adcom.com>
Cc:     Alvin Šipraga <alsi@...g-olufsen.dk>,
        linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        brcm80211-dev-list.pdl@...adcom.com,
        SHA-cyfmac-dev-list@...ineon.com,
        Pengutronix Kernel Team <kernel@...gutronix.de>
Subject: Re: [PATCH 2/2] wifi: brcmfmac: support brcm,ccode-map-trivial DT
 property

On 11.07.22 14:30, Alvin Šipraga wrote:
> From: Alvin Šipraga <alsi@...g-olufsen.dk>
> 
> Commit a21bf90e927f ("brcmfmac: use ISO3166 country code and 0 rev as
> fallback on some devices") introduced a fallback mechanism whereby a
> trivial mapping from ISO3166 country codes to firmware country code and
> revision is used on some devices. This fallback operates on the device
> level, so it is enabled only for certain supported chipsets.
> 
> In general though, the firmware country codes are determined by the CLM
> blob, which is board-specific and may vary despite the underlying
> chipset being the same.
> 
> The aforementioned commit is actually a refinement of a previous commit
> that was reverted in commit 151a7c12c4fc ("Revert "brcmfmac: use ISO3166
> country code and 0 rev as fallback"") due to regressions with a BCM4359
> device. The refinement restricted the fallback mechanism to specific
> chipsets such as the BCM4345.
> 
> We use a chipset - CYW88359 - that the driver identifies as a BCM4359
> too. But in our case, the CLM blob uses ISO3166 country codes
> internally, and all with revision 0. So the trivial mapping is exactly
> what is needed in order for the driver to sync the kernel regulatory
> domain to the firmware. This is just a matter of how the CLM blob was
> prepared by the hardware vendor. The same could hold for other boards
> too.
> 
> Although the brcm,ccode-map device tree property is useful for cases
> where the mapping is more complex, the trivial case invites a much
> simpler specification. This patch adds support for parsing the
> brcm,ccode-map-trivial device tree property. Subordinate to the more
> specific brcm,ccode-map property, this new proprety simply informs the
> driver that the fallback method should be used in every case.
> 
> In the absence of the new property in the device tree, expect no
> functional change.
> 
> Signed-off-by: Alvin Šipraga <alsi@...g-olufsen.dk>

Reviewed-by: Ahmad Fatoum <a.fatoum@...gutronix.de>

> ---
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 3 +++
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h   | 2 ++
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c       | 6 ++++++
>  3 files changed, 11 insertions(+)
> 
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> index 3ae6779fe153..db45da33adfd 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> @@ -7481,6 +7481,9 @@ int brcmf_cfg80211_wait_vif_event(struct brcmf_cfg80211_info *cfg,
>  
>  static bool brmcf_use_iso3166_ccode_fallback(struct brcmf_pub *drvr)
>  {
> +	if (drvr->settings->trivial_ccode_map)
> +		return true;
> +
>  	switch (drvr->bus_if->chip) {
>  	case BRCM_CC_4345_CHIP_ID:
>  	case BRCM_CC_43602_CHIP_ID:
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h
> index 15accc88d5c0..fe717cce5d55 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h
> @@ -38,6 +38,7 @@ extern struct brcmf_mp_global_t brcmf_mp_global;
>   * @fcmode: FWS flow control.
>   * @roamoff: Firmware roaming off?
>   * @ignore_probe_fail: Ignore probe failure.
> + * @trivial_ccode_map: Assume firmware uses ISO3166 country codes with rev 0
>   * @country_codes: If available, pointer to struct for translating country codes
>   * @bus: Bus specific platform data. Only SDIO at the mmoment.
>   */
> @@ -48,6 +49,7 @@ struct brcmf_mp_device {
>  	bool		roamoff;
>  	bool		iapp;
>  	bool		ignore_probe_fail;
> +	bool		trivial_ccode_map;
>  	struct brcmfmac_pd_cc *country_codes;
>  	const char	*board_type;
>  	unsigned char	mac[ETH_ALEN];
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> index 083ac58f466d..1add942462f8 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> @@ -24,6 +24,12 @@ static int brcmf_of_get_country_codes(struct device *dev,
>  
>  	count = of_property_count_strings(np, "brcm,ccode-map");
>  	if (count < 0) {
> +		/* If no explicit country code map is specified, check whether
> +		 * the trivial map should be used.
> +		 */
> +		settings->trivial_ccode_map =
> +			of_property_read_bool(np, "brcm,ccode-map-trivial");
> +
>  		/* The property is optional, so return success if it doesn't
>  		 * exist. Otherwise propagate the error code.
>  		 */


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