From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: [PATCH 2/2] omap3: iovmm: Support non page-aligned buffers in iommu_vmap Date: Mon, 30 May 2011 14:47:09 +0200 Message-ID: <1306759629-17232-3-git-send-email-laurent.pinchart@ideasonboard.com> References: <1306759629-17232-1-git-send-email-laurent.pinchart@ideasonboard.com> Return-path: Received: from perceval.ideasonboard.com ([95.142.166.194]:40800 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751986Ab1E3MrQ (ORCPT ); Mon, 30 May 2011 08:47:16 -0400 In-Reply-To: <1306759629-17232-1-git-send-email-laurent.pinchart@ideasonboard.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: linux-omap@vger.kernel.org Cc: teemu.tuominen@cybercom.com The IOMMU virtual memory mapping API requires page-aligned buffers. There's no hardware reason behind such a restriction. Remove it by rounding the address of the first page entry down, and adding the offset back to the IOMMU virtual address. Signed-off-by: Laurent Pinchart Cc: Hiroshi DOYU --- arch/arm/plat-omap/iovmm.c | 32 ++++++++++++++++++++++++-------- 1 files changed, 24 insertions(+), 8 deletions(-) diff --git a/arch/arm/plat-omap/iovmm.c b/arch/arm/plat-omap/iovmm.c index b82cef4..fa5ae98 100644 --- a/arch/arm/plat-omap/iovmm.c +++ b/arch/arm/plat-omap/iovmm.c @@ -60,6 +60,15 @@ static struct kmem_cache *iovm_area_cachep; +/* return the offset of the first scatterlist entry in a sg table */ +static unsigned int sgtable_offset(const struct sg_table *sgt) +{ + if (!sgt || !sgt->nents) + return 0; + + return sgt->sgl->offset; +} + /* return total bytes of sg buffers */ static size_t sgtable_len(const struct sg_table *sgt) { @@ -72,11 +81,17 @@ static size_t sgtable_len(const struct sg_table *sgt) for_each_sg(sgt->sgl, sg, sgt->nents, i) { size_t bytes; - bytes = sg_dma_len(sg); + bytes = sg_dma_len(sg) + sg->offset; if (!iopgsz_ok(bytes)) { - pr_err("%s: sg[%d] not iommu pagesize(%x)\n", - __func__, i, bytes); + pr_err("%s: sg[%d] not iommu pagesize(%u %u)\n", + __func__, i, bytes, sg->offset); + return 0; + } + + if (i && sg->offset) { + pr_err("%s: sg[%d] offset not allowed in internal " + "entries\n", __func__, i); return 0; } @@ -207,8 +222,8 @@ static void *vmap_sg(const struct sg_table *sgt) u32 pa; int err; - pa = sg_phys(sg); - bytes = sg_dma_len(sg); + pa = sg_phys(sg) - sg->offset; + bytes = sg_dma_len(sg) + sg->offset; BUG_ON(bytes != PAGE_SIZE); @@ -485,8 +500,8 @@ static int map_iovm_area(struct iommu *obj, struct iovm_struct *new, size_t bytes; struct iotlb_entry e; - pa = sg_phys(sg); - bytes = sg_dma_len(sg); + pa = sg_phys(sg) - sg->offset; + bytes = sg_dma_len(sg) + sg->offset; flags &= ~IOVMF_PGSZ_MASK; pgsz = bytes_to_iopgsz(bytes); @@ -666,7 +681,7 @@ u32 iommu_vmap(struct iommu *obj, u32 da, const struct sg_table *sgt, if (IS_ERR_VALUE(da)) vunmap_sg(va); - return da; + return da + sgtable_offset(sgt); } EXPORT_SYMBOL_GPL(iommu_vmap); @@ -685,6 +700,7 @@ struct sg_table *iommu_vunmap(struct iommu *obj, u32 da) * 'sgt' is allocated before 'iommu_vmalloc()' is called. * Just returns 'sgt' to the caller to free */ + da &= PAGE_MASK; sgt = unmap_vm_area(obj, da, vunmap_sg, IOVMF_DISCONT | IOVMF_MMIO); if (!sgt) dev_dbg(obj->dev, "%s: No sgt\n", __func__); -- 1.7.3.4