From patchwork Mon Jan 29 17:02:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 13536063 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 C053915A4AC; Mon, 29 Jan 2024 17:02:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=89.234.176.197 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706547781; cv=none; b=OJLz/O9puoXGg7YYcbciu88XW/LagzY7WdsTdZxEDu3gVi1F2g30iSmAeFKpEOlVNxrstl0KWbZ4dbGSK43RcCBpz9h80mzuwEpLPXAucVId52Ewt2v/W7AEfw/UqX2gAIDSRnRJNIV+3WCUWzZSNYz+EF63WRF/GVVlHUmZNns= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706547781; c=relaxed/simple; bh=UmEplxjcutZ/aaDgkwmjqVZy3IpHxf4/5tz4vN9kxyA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GJx12hkzffpgXFYaPxoTJqYbwbQgeQ+0KLD1uv0Kxe0jyGD3lPIizNXlzEugmHR1YkjEzI5/9xO0V7dID0shpvdgFFFqt9Tk0q27JnDTK/4lUqi9gAIsPUHYqI21PLE0Oys3jDFVOBk7/ts29sQWrbHXfHtGqCvLk0NLcpDPNc8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=crapouillou.net; spf=pass smtp.mailfrom=crapouillou.net; dkim=pass (1024-bit key) header.d=crapouillou.net header.i=@crapouillou.net header.b=4QQrUwGx; arc=none smtp.client-ip=89.234.176.197 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="4QQrUwGx" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1706547740; 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: in-reply-to:in-reply-to:references:references; bh=/0YZL7D5wfQtXZEBgkttnzz1qHadNtN8B09YGKH9qPc=; b=4QQrUwGxB/krxFoltCT9bjAvaHymTQh0LMEK3wG0UcOru+QYEW0LnHIiMi5pBKBFnrPdWD QUXwFZX7/nCdx6A1J4S6+m5Cvl1SB41GLrhxMaULwjkcl0/1VTEDcc/Oa7jEhZRQLSRfqq LfKqEqppAygtDNmFgpsKFnIn/5Epu+I= From: Paul Cercueil To: Jonathan Cameron , Jonathan Corbet , Lars-Peter Clausen , Vinod Koul , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= Cc: Daniel Vetter , Nuno Sa , Michael Hennerich , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, linux-iio@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, Paul Cercueil Subject: [PATCH v6 5/6] iio: buffer-dmaengine: Support new DMABUF based userspace API Date: Mon, 29 Jan 2024 18:02:00 +0100 Message-ID: <20240129170201.133785-6-paul@crapouillou.net> In-Reply-To: <20240129170201.133785-1-paul@crapouillou.net> References: <20240129170201.133785-1-paul@crapouillou.net> Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Use the functions provided by the buffer-dma core to implement the DMABUF userspace API in the buffer-dmaengine IIO buffer implementation. Since we want to be able to transfer an arbitrary number of bytes and not necesarily the full DMABUF, the associated scatterlist is converted to an array of DMA addresses + lengths, which is then passed to dmaengine_prep_slave_dma_array(). Signed-off-by: Paul Cercueil --- v3: Use the new dmaengine_prep_slave_dma_array(), and adapt the code to work with the new functions introduced in industrialio-buffer-dma.c. v5: - Use the new dmaengine_prep_slave_dma_vec(). - Restrict to input buffers, since output buffers are not yet supported by IIO buffers. v6: - Populate .lock_queue / .unlock_queue callbacks - Switch to atomic memory allocations in .submit_queue, because of the dma_fence critical section - Make sure that the size of the scatterlist is enough --- .../buffer/industrialio-buffer-dmaengine.c | 58 +++++++++++++++++-- 1 file changed, 52 insertions(+), 6 deletions(-) diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c index 45fe7d0d42ee..c4cfdb0c1231 100644 --- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c +++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c @@ -64,15 +64,54 @@ static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue, struct dmaengine_buffer *dmaengine_buffer = iio_buffer_to_dmaengine_buffer(&queue->buffer); struct dma_async_tx_descriptor *desc; + struct scatterlist *sgl; + struct dma_vec *vecs; dma_cookie_t cookie; + size_t len_total; + size_t max_size; + unsigned int i; + int nents; - block->bytes_used = min(block->size, dmaengine_buffer->max_size); - block->bytes_used = round_down(block->bytes_used, - dmaengine_buffer->align); + if (queue->buffer.direction != IIO_BUFFER_DIRECTION_IN) { + /* We do not yet support output buffers. */ + return -EINVAL; + } - desc = dmaengine_prep_slave_single(dmaengine_buffer->chan, - block->phys_addr, block->bytes_used, DMA_DEV_TO_MEM, - DMA_PREP_INTERRUPT); + if (block->sg_table) { + sgl = block->sg_table->sgl; + nents = sg_nents_for_len(sgl, block->bytes_used); + if (nents < 0) + return nents; + + vecs = kmalloc_array(nents, sizeof(*vecs), GFP_ATOMIC); + if (!vecs) + return -ENOMEM; + + len_total = block->bytes_used; + + for (i = 0; i < nents; i++) { + vecs[i].addr = sg_dma_address(sgl); + vecs[i].len = min(sg_dma_len(sgl), len_total); + len_total -= vecs[i].len; + + sgl = sg_next(sgl); + } + + desc = dmaengine_prep_slave_dma_vec(dmaengine_buffer->chan, + vecs, nents, DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT); + kfree(vecs); + } else { + max_size = min(block->size, dmaengine_buffer->max_size); + max_size = round_down(max_size, dmaengine_buffer->align); + block->bytes_used = max_size; + + desc = dmaengine_prep_slave_single(dmaengine_buffer->chan, + block->phys_addr, + block->bytes_used, + DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT); + } if (!desc) return -ENOMEM; @@ -120,6 +159,13 @@ static const struct iio_buffer_access_funcs iio_dmaengine_buffer_ops = { .data_available = iio_dma_buffer_data_available, .release = iio_dmaengine_buffer_release, + .enqueue_dmabuf = iio_dma_buffer_enqueue_dmabuf, + .attach_dmabuf = iio_dma_buffer_attach_dmabuf, + .detach_dmabuf = iio_dma_buffer_detach_dmabuf, + + .lock_queue = iio_dma_buffer_lock_queue, + .unlock_queue = iio_dma_buffer_unlock_queue, + .modes = INDIO_BUFFER_HARDWARE, .flags = INDIO_BUFFER_FLAG_FIXED_WATERMARK, };