From patchwork Mon Jan 8 12:00:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 13513363 Received: from aposti.net (aposti.net [89.234.176.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 84A33405CC; Mon, 8 Jan 2024 12:10:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=crapouillou.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=crapouillou.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=crapouillou.net header.i=@crapouillou.net header.b="W6fod49M" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1704715263; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=kw2xnPE5HtY1SEvsv8OuzuBAyMF2igZ6CutMKzqtu08=; b=W6fod49MZzGKeKASfexzXo/74JFcIFld1pbmYxXq7OXhAtPX5G7Ifl0VWUswisMuN4S04y 5NLkk/CClNpn75kJB2PiGGoRGMhR8rj1e35NH8jmlUixSdz4bWBc396mUHcI9K7lAaVlvM g+LHGTNPldL6HMuN9Gh4QWWyJURIlkw= From: Paul Cercueil To: Greg Kroah-Hartman , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= , Jonathan Corbet Cc: Jonathan Cameron , =?utf-8?q?Nuno_S=C3=A1?= , Michael Hennerich , Andrzej Pietrasiewicz , linux-usb@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, Paul Cercueil Subject: [PATCH v3 0/4] usb: gadget: functionfs: DMABUF import interface Date: Mon, 8 Jan 2024 13:00:52 +0100 Message-ID: <20240108120056.22165-1-paul@crapouillou.net> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam: Yes Hi, This small patchset adds three new IOCTLs that can be used to attach, detach, or transfer from/to a DMABUF object. This interface is being used at Analog Devices, to transfer data from high-speed transceivers to USB in a zero-copy fashion, using also the DMABUF import interface to the IIO subsystem which is being upstreamed in parallel [1] (and has high chances to be accepted for 5.9, I think Jonathan can confirm). The two are used by the Libiio software [2]. On a ZCU102 board with a FMComms3 daughter board, using the combination of these two new interfaces yields a drastic improvement of the throughput, from about 127 MiB/s using IIO's buffer read/write interface + read/write to the FunctionFS endpoints, to about 274 MiB/s when passing around DMABUFs, for a lower CPU usage (0.85 load avg. before, vs. 0.65 after). Right now, *technically* there are no users of this interface, as Analog Devices wants to wait until both interfaces are accepted upstream to merge the DMABUF code in Libiio into the main branch, and Jonathan wants to wait and see if this patchset is accepted to greenlight the DMABUF interface in IIO as well. I think this isn't really a problem; once everybody is happy with its part of the cake, we can merge them all at once. This is obviously for 5.9, and based on next-20240108. Changelog: - [3/4]: - Inline to_ffs_dma_fence() which was called only once. - Simplify ffs_dma_resv_lock() - Add comment explaining why we unref twice in ffs_dmabuf_detach() - Document uapi struct usb_ffs_dmabuf_transfer_req and IOCTLs - [4/4]: New patch, as I figured out having documentation wouldn't hurt. Cheers, -Paul [1] https://lore.kernel.org/linux-iio/219abc43b4fdd4a13b307ed2efaa0e6869e68e3f.camel@gmail.com/T/ [2] https://github.com/analogdevicesinc/libiio/tree/pcercuei/dev-new-dmabuf-api Paul Cercueil (4): usb: gadget: Support already-mapped DMA SGs usb: gadget: functionfs: Factorize wait-for-endpoint code usb: gadget: functionfs: Add DMABUF import interface Documentation: usb: Document FunctionFS DMABUF API Documentation/usb/functionfs.rst | 36 +++ drivers/usb/gadget/function/f_fs.c | 463 ++++++++++++++++++++++++++-- drivers/usb/gadget/udc/core.c | 7 +- include/linux/usb/gadget.h | 2 + include/uapi/linux/usb/functionfs.h | 41 +++ 5 files changed, 528 insertions(+), 21 deletions(-)