Return-path: Received: from mail.kernel.org ([198.145.29.99]:53980 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751522AbeEDRoG (ORCPT ); Fri, 4 May 2018 13:44:06 -0400 From: "Luis R. Rodriguez" To: gregkh@linuxfoundation.org Cc: akpm@linux-foundation.org, keescook@chromium.org, josh@joshtriplett.org, teg@jklm.no, wagi@monom.org, hdegoede@redhat.com, andresx7@gmail.com, zohar@linux.vnet.ibm.com, kubakici@wp.pl, shuah@kernel.org, mfuzzey@parkeon.com, dhowells@redhat.com, pali.rohar@gmail.com, tiwai@suse.de, kvalo@codeaurora.org, arend.vanspriel@broadcom.com, zajec5@gmail.com, nbroeking@me.com, markivx@codeaurora.org, broonie@kernel.org, dmitry.torokhov@gmail.com, dwmw2@infradead.org, torvalds@linux-foundation.org, Abhay_Salunke@dell.com, bjorn.andersson@linaro.org, jewalt@lgsinnovations.com, oneukum@suse.com, cantabile.desu@gmail.com, ast@fb.com, hare@suse.com, jejb@linux.vnet.ibm.com, martin.petersen@oracle.com, khc@pm.waw.pl, davem@davemloft.net, maco@android.com, arve@android.com, tkjos@android.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, "Luis R. Rodriguez" Subject: [PATCH v5 4/6] firmware_loader: document firmware_sysfs_fallback() Date: Fri, 4 May 2018 10:43:53 -0700 Message-Id: <20180504174356.13227-5-mcgrof@kernel.org> (sfid-20180504_194555_399706_D864C170) In-Reply-To: <20180504174356.13227-1-mcgrof@kernel.org> References: <20180504174356.13227-1-mcgrof@kernel.org> Sender: linux-wireless-owner@vger.kernel.org List-ID: This also sets the expecations for future fallback interfaces, even if they are not exported. Signed-off-by: Luis R. Rodriguez --- drivers/base/firmware_loader/fallback.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c index 3db9e0f225ac..9169e7b9800c 100644 --- a/drivers/base/firmware_loader/fallback.c +++ b/drivers/base/firmware_loader/fallback.c @@ -662,6 +662,26 @@ static bool fw_run_sysfs_fallback(enum fw_opt opt_flags) return fw_force_sysfs_fallback(opt_flags); } +/** + * firmware_fallback_sysfs() - use the fallback mechanism to find firmware + * @fw: pointer to firmware image + * @name: name of firmware file to look for + * @device: device for which firmware is being loaded + * @opt_flags: options to control firmware loading behaviour + * @ret: return value from direct lookup which triggered the fallback mechanism + * + * This function is called if direct lookup for the firmware failed, it enables + * a fallback mechanism through userspace by exposing a sysfs loading + * interface. Userspace is in charge of loading the firmware through the syfs + * loading interface. This syfs fallback mechanism may be disabled completely + * on a system by setting the proc sysctl value ignore_sysfs_fallback to true. + * If this false we check if the internal API caller set the @FW_OPT_NOFALLBACK + * flag, if so it would also disable the fallback mechanism. A system may want + * to enfoce the sysfs fallback mechanism at all times, it can do this by + * setting ignore_sysfs_fallback to false and force_sysfs_fallback to true. + * Enabling force_sysfs_fallback is functionally equivalent to build a kernel + * with CONFIG_FW_LOADER_USER_HELPER_FALLBACK. + **/ int firmware_fallback_sysfs(struct firmware *fw, const char *name, struct device *device, enum fw_opt opt_flags, -- 2.17.0