From patchwork Wed Dec 13 17:17:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Murphy X-Patchwork-Id: 13491670 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 8B6EAAB; Wed, 13 Dec 2023 09:18:30 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3E9621576; Wed, 13 Dec 2023 09:19:16 -0800 (PST) Received: from e121345-lin.cambridge.arm.com (e121345-lin.cambridge.arm.com [10.1.196.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 1B3323F762; Wed, 13 Dec 2023 09:18:26 -0800 (PST) From: Robin Murphy To: Joerg Roedel , Christoph Hellwig Cc: Vineet Gupta , Russell King , Catalin Marinas , Will Deacon , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Paul Walmsley , Palmer Dabbelt , Albert Ou , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Suravee Suthikulpanit , David Woodhouse , Lu Baolu , Niklas Schnelle , Matthew Rosato , Gerald Schaefer , Jean-Philippe Brucker , Rob Herring , Frank Rowand , Marek Szyprowski , Jason Gunthorpe , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, iommu@lists.linux.dev, devicetree@vger.kernel.org, Rob Herring , Jason Gunthorpe Subject: [PATCH v2 2/7] OF: Simplify DMA range calculations Date: Wed, 13 Dec 2023 17:17:55 +0000 Message-Id: <368a546e36235bd0008f66838d0c8edcd864ab94.1702486837.git.robin.murphy@arm.com> X-Mailer: git-send-email 2.39.2.101.g768bb238c484.dirty In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Juggling start, end, and size values for a range is somewhat redundant and a little hard to follow. Consolidate down to just using inclusive start and end, which saves us worrying about size overflows for full 64-bit ranges (note that passing a potentially-overflowed value through to arch_setup_dma_ops() is benign for all current implementations, and this is working towards removing that anyway). Acked-by: Rob Herring Reviewed-by: Jason Gunthorpe Signed-off-by: Robin Murphy --- drivers/of/device.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/drivers/of/device.c b/drivers/of/device.c index 526a42cdf66e..51062a831970 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -97,7 +97,7 @@ int of_dma_configure_id(struct device *dev, struct device_node *np, const struct bus_dma_region *map = NULL; struct device_node *bus_np; u64 dma_start = 0; - u64 mask, end, size = 0; + u64 mask, end = 0; bool coherent; int ret; @@ -118,17 +118,15 @@ int of_dma_configure_id(struct device *dev, struct device_node *np, return ret == -ENODEV ? 0 : ret; } else { const struct bus_dma_region *r = map; - u64 dma_end = 0; /* Determine the overall bounds of all DMA regions */ for (dma_start = ~0; r->size; r++) { /* Take lower and upper limits */ if (r->dma_start < dma_start) dma_start = r->dma_start; - if (r->dma_start + r->size > dma_end) - dma_end = r->dma_start + r->size; + if (r->dma_start + r->size > end) + end = r->dma_start + r->size; } - size = dma_end - dma_start; } /* @@ -142,16 +140,15 @@ int of_dma_configure_id(struct device *dev, struct device_node *np, dev->dma_mask = &dev->coherent_dma_mask; } - if (!size && dev->coherent_dma_mask) - size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); - else if (!size) - size = 1ULL << 32; + if (!end && dev->coherent_dma_mask) + end = dev->coherent_dma_mask; + else if (!end) + end = (1ULL << 32) - 1; /* * Limit coherent and dma mask based on size and default mask * set by the driver. */ - end = dma_start + size - 1; mask = DMA_BIT_MASK(ilog2(end) + 1); dev->coherent_dma_mask &= mask; *dev->dma_mask &= mask; @@ -177,7 +174,7 @@ int of_dma_configure_id(struct device *dev, struct device_node *np, dev_dbg(dev, "device is%sbehind an iommu\n", iommu ? " " : " not "); - arch_setup_dma_ops(dev, dma_start, size, iommu, coherent); + arch_setup_dma_ops(dev, dma_start, end - dma_start + 1, iommu, coherent); if (!iommu) of_dma_set_restricted_buffer(dev, np);