From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932574AbdA0K05 (ORCPT ); Fri, 27 Jan 2017 05:26:57 -0500 Received: from mail-pg0-f44.google.com ([74.125.83.44]:35812 "EHLO mail-pg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932438AbdA0K02 (ORCPT ); Fri, 27 Jan 2017 05:26:28 -0500 Subject: Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for loading NVS calibration data To: =?UTF-8?Q?Pali_Roh=c3=a1r?= References: <1482598381-16513-1-git-send-email-pali.rohar@gmail.com> <1482598381-16513-3-git-send-email-pali.rohar@gmail.com> <87tw8lnei3.fsf@codeaurora.org> <20170127094342.GC24223@pali> <20170127101043.GD24223@pali> Cc: Kalle Valo , Ming Lei , "Luis R. Rodriguez" , Greg Kroah-Hartman , David Gnedt , Michal Kazior , Daniel Wagner , Tony Lindgren , Sebastian Reichel , Pavel Machek , Ivaylo Dimitrov , Aaro Koskinen , Grazvydas Ignotas , linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org From: Arend Van Spriel Message-ID: Date: Fri, 27 Jan 2017 11:19:25 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: <20170127101043.GD24223@pali> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27-1-2017 11:10, Pali Rohár wrote: > On Friday 27 January 2017 11:05:32 Arend Van Spriel wrote: >> On 27-1-2017 10:43, Pali Rohár wrote: >>> On Friday 27 January 2017 09:33:40 Kalle Valo wrote: >>>> Pali Rohár writes: >>>> >>>>> NVS calibration data for wl1251 are model specific. Every one device with >>>>> wl1251 chip has different and calibrated in factory. >>>>> >>>>> Not all wl1251 chips have own EEPROM where are calibration data stored. And >>>>> in that case there is no "standard" place. Every device has stored them on >>>>> different place (some in rootfs file, some in dedicated nand partition, >>>>> some in another proprietary structure). >>>>> >>>>> Kernel wl1251 driver cannot support every one different storage decided by >>>>> device manufacture so it will use request_firmware_prefer_user() call for >>>>> loading NVS calibration data and userspace helper will be responsible to >>>>> prepare correct data. >>>>> >>>>> In case userspace helper fails request_firmware_prefer_user() still try to >>>>> load data file directly from VFS as fallback mechanism. >>>>> >>>>> On Nokia N900 device which has wl1251 chip, NVS calibration data are stored >>>>> in CAL nand partition. CAL is proprietary Nokia key/value format for nand >>>>> devices. >>>>> >>>>> With this patch it is finally possible to load correct model specific NVS >>>>> calibration data for Nokia N900. >>>>> >>>>> Signed-off-by: Pali Rohár >>>>> --- >>>>> drivers/net/wireless/ti/wl1251/Kconfig | 1 + >>>>> drivers/net/wireless/ti/wl1251/main.c | 2 +- >>>>> 2 files changed, 2 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/net/wireless/ti/wl1251/Kconfig b/drivers/net/wireless/ti/wl1251/Kconfig >>>>> index 7142ccf..affe154 100644 >>>>> --- a/drivers/net/wireless/ti/wl1251/Kconfig >>>>> +++ b/drivers/net/wireless/ti/wl1251/Kconfig >>>>> @@ -2,6 +2,7 @@ config WL1251 >>>>> tristate "TI wl1251 driver support" >>>>> depends on MAC80211 >>>>> select FW_LOADER >>>>> + select FW_LOADER_USER_HELPER >>>>> select CRC7 >>>>> ---help--- >>>>> This will enable TI wl1251 driver support. The drivers make >>>>> diff --git a/drivers/net/wireless/ti/wl1251/main.c b/drivers/net/wireless/ti/wl1251/main.c >>>>> index 208f062..24f8866 100644 >>>>> --- a/drivers/net/wireless/ti/wl1251/main.c >>>>> +++ b/drivers/net/wireless/ti/wl1251/main.c >>>>> @@ -110,7 +110,7 @@ static int wl1251_fetch_nvs(struct wl1251 *wl) >>>>> struct device *dev = wiphy_dev(wl->hw->wiphy); >>>>> int ret; >>>>> >>>>> - ret = request_firmware(&fw, WL1251_NVS_NAME, dev); >>>>> + ret = request_firmware_prefer_user(&fw, WL1251_NVS_NAME, dev); >>>> >>>> I don't see the need for this. Just remove the default nvs file from >>>> filesystem and the fallback user helper will be always used, right? >>> >>> It is part of linux-firmware repository. And already part of all >>> previous versions of linux-firmware packages in lot of linux >>> distributions. So removing it is not possible... >> >> You are probably saying that on your platform you can not remove >> anything from /lib/firmware, right? I don't see how you come from "it is >> part of firmware package" to "removing is not possible". Trying to >> understand this and it makes no sense. > > It is already in linux distribution packages. If I remove that file from > file system it will be placed there again by package management or it it > will throw error message about system integrity (missing file, etc...). > > Also that file is already in linux-firmware git and so is propagated to > /lib/firmware by anybody who is using linux-firmware. > >>>> Like we discussed earlier, the default nvs file should not be used by >>>> normal users. >>> >>> But already is and we need to deal with this fact. >> >> Why? > > Because everybody has already installed it. > >> Are there other platforms that use the default nvs file and have a >> working wifi. > > I do not know. > >> So your "removing is not possible" would be about >> regression for those? > > Yes, that is possible. > > Also you can use wifi on Nokia N900 with this default file. Yes it is > not recommended and probably has performance problems... but more people > use it for SSH and it is working. Pavel could confirm this. > > So yes, if you remove that file *now* there is regression for Nokia N900 > when you are using SSH over wifi. So you are changing the behavior for all platforms using wl1251, but the user-helper preference is (probably) only applicable for N900, right? So for those other platforms there will be a delay waiting for user-mode helper to fail, before trying to get nvs file from /lib/firmware. Regards, Arend