From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751922AbdCCQlv (ORCPT ); Fri, 3 Mar 2017 11:41:51 -0500 Received: from galahad.ideasonboard.com ([185.26.127.97]:40455 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751459AbdCCQls (ORCPT ); Fri, 3 Mar 2017 11:41:48 -0500 From: Laurent Pinchart To: dri-devel@lists.freedesktop.org Cc: Laura Abbott , Sumit Semwal , Riley Andrews , arve@android.com, devel@driverdev.osuosl.org, romlem@google.com, Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, Mark Brown , Daniel Vetter , linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Subject: Re: [RFC PATCH 10/12] staging: android: ion: Use CMA APIs directly Date: Fri, 03 Mar 2017 18:41:33 +0200 Message-ID: <2140021.hmlAgxcLbU@avalon> User-Agent: KMail/4.14.10 (Linux/4.9.6-gentoo-r1; KDE/4.14.28; x86_64; ; ) In-Reply-To: <1488491084-17252-11-git-send-email-labbott@redhat.com> References: <1488491084-17252-1-git-send-email-labbott@redhat.com> <1488491084-17252-11-git-send-email-labbott@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Laura, Thank you for the patch. On Thursday 02 Mar 2017 13:44:42 Laura Abbott wrote: > When CMA was first introduced, its primary use was for DMA allocation > and the only way to get CMA memory was to call dma_alloc_coherent. This > put Ion in an awkward position since there was no device structure > readily available and setting one up messed up the coherency model. > These days, CMA can be allocated directly from the APIs. Switch to using > this model to avoid needing a dummy device. This also avoids awkward > caching questions. If the DMA mapping API isn't suitable for today's requirements anymore, I believe that's what needs to be fixed, instead of working around the problem by introducing another use-case-specific API. > Signed-off-by: Laura Abbott > --- > drivers/staging/android/ion/ion_cma_heap.c | 97 +++++++-------------------- > 1 file changed, 26 insertions(+), 71 deletions(-) > > diff --git a/drivers/staging/android/ion/ion_cma_heap.c > b/drivers/staging/android/ion/ion_cma_heap.c index d562fd7..6838825 100644 > --- a/drivers/staging/android/ion/ion_cma_heap.c > +++ b/drivers/staging/android/ion/ion_cma_heap.c > @@ -19,24 +19,19 @@ > #include > #include > #include > -#include > +#include > +#include > > #include "ion.h" > #include "ion_priv.h" > > struct ion_cma_heap { > struct ion_heap heap; > - struct device *dev; > + struct cma *cma; > }; > > #define to_cma_heap(x) container_of(x, struct ion_cma_heap, heap) > > -struct ion_cma_buffer_info { > - void *cpu_addr; > - dma_addr_t handle; > - struct sg_table *table; > -}; > - > > /* ION CMA heap operations functions */ > static int ion_cma_allocate(struct ion_heap *heap, struct ion_buffer > *buffer, @@ -44,93 +39,53 @@ static int ion_cma_allocate(struct ion_heap > *heap, struct ion_buffer *buffer, unsigned long flags) > { > struct ion_cma_heap *cma_heap = to_cma_heap(heap); > - struct device *dev = cma_heap->dev; > - struct ion_cma_buffer_info *info; > - > - dev_dbg(dev, "Request buffer allocation len %ld\n", len); > - > - if (buffer->flags & ION_FLAG_CACHED) > - return -EINVAL; > + struct sg_table *table; > + struct page *pages; > + int ret; > > - info = kzalloc(sizeof(*info), GFP_KERNEL); > - if (!info) > + pages = cma_alloc(cma_heap->cma, len, 0); > + if (!pages) > return -ENOMEM; > > - info->cpu_addr = dma_alloc_coherent(dev, len, &(info->handle), > - GFP_HIGHUSER | __GFP_ZERO); > - > - if (!info->cpu_addr) { > - dev_err(dev, "Fail to allocate buffer\n"); > + table = kmalloc(sizeof(struct sg_table), GFP_KERNEL); > + if (!table) > goto err; > - } > > - info->table = kmalloc(sizeof(*info->table), GFP_KERNEL); > - if (!info->table) > + ret = sg_alloc_table(table, 1, GFP_KERNEL); > + if (ret) > goto free_mem; > > - if (dma_get_sgtable(dev, info->table, info->cpu_addr, info->handle, > - len)) > - goto free_table; > - /* keep this for memory release */ > - buffer->priv_virt = info; > - buffer->sg_table = info->table; > - dev_dbg(dev, "Allocate buffer %p\n", buffer); > + sg_set_page(table->sgl, pages, len, 0); > + > + buffer->priv_virt = pages; > + buffer->sg_table = table; > return 0; > > -free_table: > - kfree(info->table); > free_mem: > - dma_free_coherent(dev, len, info->cpu_addr, info->handle); > + kfree(table); > err: > - kfree(info); > + cma_release(cma_heap->cma, pages, buffer->size); > return -ENOMEM; > } > > static void ion_cma_free(struct ion_buffer *buffer) > { > struct ion_cma_heap *cma_heap = to_cma_heap(buffer->heap); > - struct device *dev = cma_heap->dev; > - struct ion_cma_buffer_info *info = buffer->priv_virt; > + struct page *pages = buffer->priv_virt; > > - dev_dbg(dev, "Release buffer %p\n", buffer); > /* release memory */ > - dma_free_coherent(dev, buffer->size, info->cpu_addr, info->handle); > + cma_release(cma_heap->cma, pages, buffer->size); > /* release sg table */ > - sg_free_table(info->table); > - kfree(info->table); > - kfree(info); > -} > - > -static int ion_cma_mmap(struct ion_heap *mapper, struct ion_buffer *buffer, > - struct vm_area_struct *vma) > -{ > - struct ion_cma_heap *cma_heap = to_cma_heap(buffer->heap); > - struct device *dev = cma_heap->dev; > - struct ion_cma_buffer_info *info = buffer->priv_virt; > - > - return dma_mmap_coherent(dev, vma, info->cpu_addr, info->handle, > - buffer->size); > -} > - > -static void *ion_cma_map_kernel(struct ion_heap *heap, > - struct ion_buffer *buffer) > -{ > - struct ion_cma_buffer_info *info = buffer->priv_virt; > - /* kernel memory mapping has been done at allocation time */ > - return info->cpu_addr; > -} > - > -static void ion_cma_unmap_kernel(struct ion_heap *heap, > - struct ion_buffer *buffer) > -{ > + sg_free_table(buffer->sg_table); > + kfree(buffer->sg_table); > } > > static struct ion_heap_ops ion_cma_ops = { > .allocate = ion_cma_allocate, > .free = ion_cma_free, > - .map_user = ion_cma_mmap, > - .map_kernel = ion_cma_map_kernel, > - .unmap_kernel = ion_cma_unmap_kernel, > + .map_user = ion_heap_map_user, > + .map_kernel = ion_heap_map_kernel, > + .unmap_kernel = ion_heap_unmap_kernel, > }; > > struct ion_heap *ion_cma_heap_create(struct ion_platform_heap *data) > @@ -147,7 +102,7 @@ struct ion_heap *ion_cma_heap_create(struct > ion_platform_heap *data) * get device from private heaps data, later it > will be > * used to make the link with reserved CMA memory > */ > - cma_heap->dev = data->priv; > + cma_heap->cma = data->priv; > cma_heap->heap.type = ION_HEAP_TYPE_DMA; > return &cma_heap->heap; > } -- Regards, Laurent Pinchart