From patchwork Wed Jan 21 04:16:47 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sumit Semwal X-Patchwork-Id: 5674561 Return-Path: X-Original-To: patchwork-linux-media@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 43F5BC058D for ; Wed, 21 Jan 2015 04:18:00 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 32550204D1 for ; Wed, 21 Jan 2015 04:17:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DDC82204C9 for ; Wed, 21 Jan 2015 04:17:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754175AbbAUERi (ORCPT ); Tue, 20 Jan 2015 23:17:38 -0500 Received: from mail-pa0-f45.google.com ([209.85.220.45]:36129 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754060AbbAUERh (ORCPT ); Tue, 20 Jan 2015 23:17:37 -0500 Received: by mail-pa0-f45.google.com with SMTP id lf10so50232334pab.4 for ; Tue, 20 Jan 2015 20:17:36 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=g9UnTw15stQ1k8BuuIkkFBCEuA5Ep/PHx48XIaaOM6c=; b=G3mIA56phCF/h0YR6K84PhMQeCGOFFFeuD8wEob40GsZemnBqXyQdUs3d0tXxES0iR Zr6SSQ6qf6uQsEHt4GQmjFLgAx2RwPxgip+QTj7YOpRxF5NEd9IwZgrdx4iKhcDsAtov uQyqX6yaRqfNhlkDXc+E/v7ZF2JiHm5LoR98WdvbxHi3OE1bcWMY9R3dKcYjrt58UmoP ftgMK2R0ncKTQUXP8aMqblRA8BrwcRm6ZTgRRtEjxZXErgVzFVNHu6z2q/nM6CvRhhKi 47olesWPFP29Q9ZYX4SSNvsfuN7Hdc97JgfqceUdynlDbRYRPuICyfJaP8Ps849uGEoH +veQ== X-Gm-Message-State: ALoCoQlZ/AA+jYr3b1j5yAHiWYsrFgLX7QAxhJfQKKjYlFTO4kSDMT1a+qMghTZKt8FPn88FhBde X-Received: by 10.68.193.135 with SMTP id ho7mr59196430pbc.103.1421813856790; Tue, 20 Jan 2015 20:17:36 -0800 (PST) Received: from ss-ubuntu.lan ([106.51.225.38]) by mx.google.com with ESMTPSA id hx9sm4684773pad.38.2015.01.20.20.17.32 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 20 Jan 2015 20:17:35 -0800 (PST) From: Sumit Semwal To: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org Cc: linaro-kernel@lists.linaro.org, robdclark@gmail.com, daniel@ffwll.ch, m.szyprowski@samsung.com, t.stanislaws@samsung.com, Sumit Semwal Subject: [RFCv2 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms Date: Wed, 21 Jan 2015 09:46:47 +0530 Message-Id: <1421813807-9178-3-git-send-email-sumit.semwal@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1421813807-9178-1-git-send-email-sumit.semwal@linaro.org> References: <1421813807-9178-1-git-send-email-sumit.semwal@linaro.org> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add some helpers to share the constraints of devices while attaching to the dmabuf buffer. At each attach, the constraints are calculated based on the following: - dma_mask, coherent_dma_mask from struct device, - max_segment_size, max_segment_count, segment_boundary_mask from device_dma_parameters. In case the attaching device's constraints don't match up, attach() fails. At detach, the constraints are recalculated based on the remaining attached devices. Two helpers are added: - dma_buf_get_constraints - which gives the current constraints as calculated during each attach on the buffer till the time, - dma_buf_recalc_constraints - which recalculates the constraints for all currently attached devices for the 'paranoid' ones amongst us. The idea of this patch is largely taken from Rob Clark's RFC at https://lkml.org/lkml/2012/7/19/285, and the comments received on it. Cc: Rob Clark Signed-off-by: Sumit Semwal --- drivers/dma-buf/dma-buf.c | 132 +++++++++++++++++++++++++++++++++++++++++++++- include/linux/dma-buf.h | 22 ++++++++ 2 files changed, 153 insertions(+), 1 deletion(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 5be225c..3781f43 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -264,6 +264,77 @@ static inline int is_dma_buf_file(struct file *file) return file->f_op == &dma_buf_fops; } +static inline void init_constraints(struct dma_buf_constraints *cons) +{ + cons->coherent_dma_mask = (u64)-1; + cons->dma_mask = (u64)-1; + cons->dma_parms.max_segment_count = (unsigned int)-1; + cons->dma_parms.max_segment_size = (unsigned int)-1; + cons->dma_parms.segment_boundary_mask = (unsigned int)-1; +} + +/* + * calc_constraints - calculates if the new attaching device's constraints + * match, with the constraints of already attached devices; if yes, returns + * the constraints; else return ERR_PTR(-EINVAL) + */ +static int calc_constraints(struct device *dev, + struct dma_buf_constraints *calc_cons) +{ + struct dma_buf_constraints cons = *calc_cons; + + cons.dma_mask &= dma_get_mask(dev); + /* TODO: Check if this is the right way for coherent_mask ? */ + cons.coherent_dma_mask &= dev->coherent_dma_mask; + + cons.dma_parms.max_segment_count = + min(cons.dma_parms.max_segment_count, + dma_get_max_seg_count(dev)); + cons.dma_parms.max_segment_size = + min(cons.dma_parms.max_segment_size, + dma_get_max_seg_size(dev)); + cons.dma_parms.segment_boundary_mask &= + dma_get_seg_boundary(dev); + + if (!cons.dma_parms.max_segment_count || + !cons.dma_parms.max_segment_size || + !cons.dma_parms.segment_boundary_mask || + !cons.dma_mask || + !cons.coherent_dma_mask) { + pr_err("Dev: %s's constraints don't match\n", dev_name(dev)); + return -EINVAL; + } + + *calc_cons = cons; + + return 0; +} + +/* + * recalc_constraints - recalculates constraints for all attached devices; + * useful for detach() recalculation, and for dma_buf_recalc_constraints() + * helper. + * Returns recalculated constraints in recalc_cons, or error in the unlikely + * case when constraints of attached devices might have changed. + */ +static int recalc_constraints(struct dma_buf *dmabuf, + struct dma_buf_constraints *recalc_cons) +{ + struct dma_buf_constraints calc_cons; + struct dma_buf_attachment *attach; + int ret = 0; + + init_constraints(&calc_cons); + + list_for_each_entry(attach, &dmabuf->attachments, node) { + ret = calc_constraints(attach->dev, &calc_cons); + if (ret) + return ret; + } + *recalc_cons = calc_cons; + return 0; +} + /** * dma_buf_export_named - Creates a new dma_buf, and associates an anon file * with this buffer, so it can be exported. @@ -313,6 +384,9 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops, dmabuf->ops = ops; dmabuf->size = size; dmabuf->exp_name = exp_name; + + init_constraints(&dmabuf->constraints); + init_waitqueue_head(&dmabuf->poll); dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll; dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0; @@ -422,7 +496,7 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, struct device *dev) { struct dma_buf_attachment *attach; - int ret; + int ret = 0; if (WARN_ON(!dmabuf || !dev)) return ERR_PTR(-EINVAL); @@ -436,6 +510,9 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, mutex_lock(&dmabuf->lock); + if (calc_constraints(dev, &dmabuf->constraints)) + goto err_constraints; + if (dmabuf->ops->attach) { ret = dmabuf->ops->attach(dmabuf, dev, attach); if (ret) @@ -448,6 +525,7 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, err_attach: kfree(attach); +err_constraints: mutex_unlock(&dmabuf->lock); return ERR_PTR(ret); } @@ -470,6 +548,8 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) if (dmabuf->ops->detach) dmabuf->ops->detach(dmabuf, attach); + recalc_constraints(dmabuf, &dmabuf->constraints); + mutex_unlock(&dmabuf->lock); kfree(attach); } @@ -770,6 +850,56 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) } EXPORT_SYMBOL_GPL(dma_buf_vunmap); +/** + * dma_buf_get_constraints - get the *current* constraints of the dmabuf, + * as calculated during each attach(); returns error on invalid inputs + * + * @dmabuf: [in] buffer to get constraints of + * @constraints: [out] current constraints are returned in this + */ +int dma_buf_get_constraints(struct dma_buf *dmabuf, + struct dma_buf_constraints *constraints) +{ + if (WARN_ON(!dmabuf || !constraints)) + return -EINVAL; + + mutex_lock(&dmabuf->lock); + *constraints = dmabuf->constraints; + mutex_unlock(&dmabuf->lock); + return 0; +} +EXPORT_SYMBOL_GPL(dma_buf_get_constraints); + +/** + * dma_buf_recalc_constraints - *recalculate* the constraints for the buffer + * afresh, from the list of currently attached devices; this could be useful + * cross-check the current constraints, for exporters that might want to be + * 'paranoid' about the device constraints. + * + * returns error on invalid inputs + * + * @dmabuf: [in] buffer to get constraints of + * @constraints: [out] recalculated constraints are returned in this + */ +int dma_buf_recalc_constraints(struct dma_buf *dmabuf, + struct dma_buf_constraints *constraints) +{ + struct dma_buf_constraints calc_cons; + int ret = 0; + + if (WARN_ON(!dmabuf || !constraints)) + return -EINVAL; + + mutex_lock(&dmabuf->lock); + ret = recalc_constraints(dmabuf, &calc_cons); + if (!ret) + *constraints = calc_cons; + + mutex_unlock(&dmabuf->lock); + return ret; +} +EXPORT_SYMBOL_GPL(dma_buf_recalc_constraints); + #ifdef CONFIG_DEBUG_FS static int dma_buf_describe(struct seq_file *s) { diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 694e1fe..e1f7cbe 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -34,10 +34,28 @@ #include struct device; +struct device_dma_parameters; struct dma_buf; struct dma_buf_attachment; /** + * struct dma_buf_constraints - holds constraints for the dma-buf + * @dma_mask: dma_mask if the device is dma'able + * @coherent_dma_mask: like dma_mask, but for alloc_coherent mappings + * @dma_parms: collated dma_parms from all devices. + * + * This structure holds the constraints of the dma_buf, dependent on the + * currently attached devices. Semantics for each of the members are the same + * as defined in device.h + */ +struct dma_buf_constraints { + u64 dma_mask; + u64 coherent_dma_mask; + struct device_dma_parameters dma_parms; +}; + + +/** * struct dma_buf_ops - operations possible on struct dma_buf * @attach: [optional] allows different devices to 'attach' themselves to the * given buffer. It might return -EBUSY to signal that backing storage @@ -130,6 +148,7 @@ struct dma_buf { void *vmap_ptr; const char *exp_name; struct list_head list_node; + struct dma_buf_constraints constraints; void *priv; struct reservation_object *resv; @@ -211,4 +230,7 @@ void *dma_buf_vmap(struct dma_buf *); void dma_buf_vunmap(struct dma_buf *, void *vaddr); int dma_buf_debugfs_create_file(const char *name, int (*write)(struct seq_file *)); + +int dma_buf_get_constraints(struct dma_buf *, struct dma_buf_constraints *); +int dma_buf_recalc_constraints(struct dma_buf *, struct dma_buf_constraints *); #endif /* __DMA_BUF_H__ */