From patchwork Mon Feb 7 12:59:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 12737242 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7766DC433EF for ; Mon, 7 Feb 2022 13:29:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358150AbiBGN2o (ORCPT ); Mon, 7 Feb 2022 08:28:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1384812AbiBGNF1 (ORCPT ); Mon, 7 Feb 2022 08:05:27 -0500 Received: from aposti.net (aposti.net [89.234.176.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 972CCC0401C4; Mon, 7 Feb 2022 05:05:24 -0800 (PST) From: Paul Cercueil To: Jonathan Cameron Cc: Michael Hennerich , Lars-Peter Clausen , =?utf-8?q?Christian_K=C3=B6nig?= , Sumit Semwal , Jonathan Corbet , Alexandru Ardelean , dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, Paul Cercueil Subject: [PATCH v2 02/12] iio: buffer-dma: Enable buffer write support Date: Mon, 7 Feb 2022 12:59:23 +0000 Message-Id: <20220207125933.81634-3-paul@crapouillou.net> In-Reply-To: <20220207125933.81634-1-paul@crapouillou.net> References: <20220207125933.81634-1-paul@crapouillou.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org Adding write support to the buffer-dma code is easy - the write() function basically needs to do the exact same thing as the read() function: dequeue a block, read or write the data, enqueue the block when entirely processed. Therefore, the iio_buffer_dma_read() and the new iio_buffer_dma_write() now both call a function iio_buffer_dma_io(), which will perform this task. The .space_available() callback can return the exact same value as the .data_available() callback for input buffers, since in both cases we count the exact same thing (the number of bytes in each available block). Note that we preemptively reset block->bytes_used to the buffer's size in iio_dma_buffer_request_update(), as in the future the iio_dma_buffer_enqueue() function won't reset it. v2: - Fix block->state not being reset in iio_dma_buffer_request_update() for output buffers. - Only update block->bytes_used once and add a comment about why we update it. - Add a comment about why we're setting a different state for output buffers in iio_dma_buffer_request_update() - Remove useless cast to bool (!!) in iio_dma_buffer_io() Signed-off-by: Paul Cercueil Reviewed-by: Alexandru Ardelean --- drivers/iio/buffer/industrialio-buffer-dma.c | 88 ++++++++++++++++---- include/linux/iio/buffer-dma.h | 7 ++ 2 files changed, 79 insertions(+), 16 deletions(-) diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c index 1fc91467d1aa..a9f1b673374f 100644 --- a/drivers/iio/buffer/industrialio-buffer-dma.c +++ b/drivers/iio/buffer/industrialio-buffer-dma.c @@ -195,6 +195,18 @@ static void _iio_dma_buffer_block_done(struct iio_dma_buffer_block *block) block->state = IIO_BLOCK_STATE_DONE; } +static void iio_dma_buffer_queue_wake(struct iio_dma_buffer_queue *queue) +{ + __poll_t flags; + + if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) + flags = EPOLLIN | EPOLLRDNORM; + else + flags = EPOLLOUT | EPOLLWRNORM; + + wake_up_interruptible_poll(&queue->buffer.pollq, flags); +} + /** * iio_dma_buffer_block_done() - Indicate that a block has been completed * @block: The completed block @@ -212,7 +224,7 @@ void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block) spin_unlock_irqrestore(&queue->list_lock, flags); iio_buffer_block_put_atomic(block); - wake_up_interruptible_poll(&queue->buffer.pollq, EPOLLIN | EPOLLRDNORM); + iio_dma_buffer_queue_wake(queue); } EXPORT_SYMBOL_GPL(iio_dma_buffer_block_done); @@ -241,7 +253,7 @@ void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue, } spin_unlock_irqrestore(&queue->list_lock, flags); - wake_up_interruptible_poll(&queue->buffer.pollq, EPOLLIN | EPOLLRDNORM); + iio_dma_buffer_queue_wake(queue); } EXPORT_SYMBOL_GPL(iio_dma_buffer_block_list_abort); @@ -335,8 +347,24 @@ int iio_dma_buffer_request_update(struct iio_buffer *buffer) queue->fileio.blocks[i] = block; } - block->state = IIO_BLOCK_STATE_QUEUED; - list_add_tail(&block->head, &queue->incoming); + /* + * block->bytes_used may have been modified previously, e.g. by + * iio_dma_buffer_block_list_abort(). Reset it here to the + * block's so that iio_dma_buffer_io() will work. + */ + block->bytes_used = block->size; + + /* + * If it's an input buffer, mark the block as queued, and + * iio_dma_buffer_enable() will submit it. Otherwise mark it as + * done, which means it's ready to be dequeued. + */ + if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) { + block->state = IIO_BLOCK_STATE_QUEUED; + list_add_tail(&block->head, &queue->incoming); + } else { + block->state = IIO_BLOCK_STATE_DONE; + } } out_unlock: @@ -465,20 +493,12 @@ static struct iio_dma_buffer_block *iio_dma_buffer_dequeue( return block; } -/** - * iio_dma_buffer_read() - DMA buffer read callback - * @buffer: Buffer to read form - * @n: Number of bytes to read - * @user_buffer: Userspace buffer to copy the data to - * - * Should be used as the read callback for iio_buffer_access_ops - * struct for DMA buffers. - */ -int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, - char __user *user_buffer) +static int iio_dma_buffer_io(struct iio_buffer *buffer, + size_t n, char __user *user_buffer, bool is_write) { struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); struct iio_dma_buffer_block *block; + void *addr; int ret; if (n < buffer->bytes_per_datum) @@ -501,8 +521,13 @@ int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, n = rounddown(n, buffer->bytes_per_datum); if (n > block->bytes_used - queue->fileio.pos) n = block->bytes_used - queue->fileio.pos; + addr = block->vaddr + queue->fileio.pos; - if (copy_to_user(user_buffer, block->vaddr + queue->fileio.pos, n)) { + if (is_write) + ret = copy_from_user(addr, user_buffer, n); + else + ret = copy_to_user(user_buffer, addr, n); + if (ret) { ret = -EFAULT; goto out_unlock; } @@ -521,8 +546,39 @@ int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, return ret; } + +/** + * iio_dma_buffer_read() - DMA buffer read callback + * @buffer: Buffer to read form + * @n: Number of bytes to read + * @user_buffer: Userspace buffer to copy the data to + * + * Should be used as the read callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, + char __user *user_buffer) +{ + return iio_dma_buffer_io(buffer, n, user_buffer, false); +} EXPORT_SYMBOL_GPL(iio_dma_buffer_read); +/** + * iio_dma_buffer_write() - DMA buffer write callback + * @buffer: Buffer to read form + * @n: Number of bytes to read + * @user_buffer: Userspace buffer to copy the data from + * + * Should be used as the write callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_write(struct iio_buffer *buffer, size_t n, + const char __user *user_buffer) +{ + return iio_dma_buffer_io(buffer, n, (__force char *)user_buffer, true); +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_write); + /** * iio_dma_buffer_data_available() - DMA buffer data_available callback * @buf: Buffer to check for data availability diff --git a/include/linux/iio/buffer-dma.h b/include/linux/iio/buffer-dma.h index 18d3702fa95d..490b93f76fa8 100644 --- a/include/linux/iio/buffer-dma.h +++ b/include/linux/iio/buffer-dma.h @@ -132,6 +132,8 @@ int iio_dma_buffer_disable(struct iio_buffer *buffer, struct iio_dev *indio_dev); int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, char __user *user_buffer); +int iio_dma_buffer_write(struct iio_buffer *buffer, size_t n, + const char __user *user_buffer); size_t iio_dma_buffer_data_available(struct iio_buffer *buffer); int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd); int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length); @@ -142,4 +144,9 @@ int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue, void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue); void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue); +static inline size_t iio_dma_buffer_space_available(struct iio_buffer *buffer) +{ + return iio_dma_buffer_data_available(buffer); +} + #endif