From: Roger Quadros <rogerq@ti.com> To: robin.murphy@arm.com, "Christoph Hellwig" <hch@lst.de>, "Péter Ujfalusi" <peter.ujfalusi@ti.com>, "Murali Karicheri" <m-karicheri2@ti.com>, "Nori, Sekhar" <nsekhar@ti.com>, "Anna, Suman" <s-anna@ti.com> Cc: <stefan.wahren@i2se.com>, <afaerber@suse.de>, <hverkuil@xs4all.nl>, Rob Herring <robh+dt@kernel.org>, <devicetree@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Nishanth Menon <nm@ti.com> Subject: dma_mask limited to 32-bits with OF platform device Date: Wed, 12 Feb 2020 12:49:59 +0200 [thread overview] Message-ID: <c1c75923-3094-d3fc-fe8e-ee44f17b1a0a@ti.com> (raw) Hi, I'd like to understand why of_dma_configure() is limiting the dma and coherent masks instead of overriding them. see commits a5516219b102 ("of/platform: Initialise default DMA masks") ee7b1f31200d ("of: fix DMA mask generation") In of_platform_device_create_pdata(), we initialize both masks to 32-bits unconditionally, which is fine to support legacy cases. dev->dev.coherent_dma_mask = DMA_BIT_MASK(32); if (!dev->dev.dma_mask) dev->dev.dma_mask = &dev->dev.coherent_dma_mask; Then in of_dma_configure() we limit it like so. dev->coherent_dma_mask &= mask; *dev->dma_mask &= mask; This way, legitimate devices which correctly set dma-ranges in DT will never get a dma_mask above 32-bits at all. How is this expected to work? For a test, I added this in dra7.dtsi sata node. (NOTE: CONFIG_ARM_LPAE=y) diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi index 93aa65c75b45..cd8c6cea23d5 100644 --- a/arch/arm/boot/dts/dra7.dtsi +++ b/arch/arm/boot/dts/dra7.dtsi @@ -571,6 +571,8 @@ sata: sata@4a141100 { compatible = "snps,dwc-ahci"; reg = <0x4a140000 0x1100>, <0x4a141100 0x7>; + #size-cells = <2>; + dma-ranges = <0x00000000 0x00000000 0x10 0x00000000>; interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>; phys = <&sata_phy>; phy-names = "sata-phy"; ----------------------------- drivers/of/device.c ----------------------------- index e9127db7b067..1072cebad57a 100644 @@ -95,6 +95,7 @@ int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma) const struct iommu_ops *iommu; u64 mask, end; + dev_info(dev, "of_dma_configure\n"); ret = of_dma_get_range(np, &dma_addr, &paddr, &size); if (ret < 0) { /* @@ -123,7 +124,8 @@ int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma) dev_err(dev, "Adjusted size 0x%llx invalid\n", size); return -EINVAL; } - dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset); + dev_info(dev, "dma %llx paddr %llx size %llx\n", dma_addr, paddr, size); + dev_info(dev, "dma_pfn_offset(%#08lx)\n", offset); } /* @@ -152,6 +154,8 @@ int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma) mask = DMA_BIT_MASK(ilog2(end) + 1); dev->coherent_dma_mask &= mask; *dev->dma_mask &= mask; + + dev_info(dev, "end %llx, mask %llx\n", end, mask); /* ...but only set bus limit if we found valid dma-ranges earlier */ if (!ret) dev->bus_dma_limit = end; And I see. [ 1.134294] 4a140000.sata: of_platform [ 13.203917] ahci 4a140000.sata: of_dma_configure [ 13.225635] ahci 4a140000.sata: dma 0 paddr 0 size 1000000000 [ 13.266178] ahci 4a140000.sata: dma_pfn_offset(0x000000) [ 13.297621] ahci 4a140000.sata: end fffffffff, mask fffffffff [ 13.585499] ahci 4a140000.sata: dma_mask 0xffffffff, coherent_mask 0xffffffff [ 13.599082] ahci 4a140000.sata: setting 64-bit mask ffffffffffffffff Truncation of dma_mask and coherent_mask is undesired in this case. How about fixing it like so? - dev->coherent_dma_mask &= mask; - *dev->dma_mask &= mask; + dev->coherent_dma_mask = mask; + *dev->dma_mask = mask; Also this comment doesn't make sense anymore? /* * Limit coherent and dma mask based on size and default mask * set by the driver. */ cheers, -roger -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
next reply other threads:[~2020-02-12 10:50 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-12 10:49 Roger Quadros [this message] 2020-02-12 11:37 ` Robin Murphy 2020-02-12 12:33 ` Roger Quadros 2020-02-12 14:04 ` Robin Murphy 2020-02-12 17:57 ` Christoph Hellwig 2020-02-17 13:21 ` Christoph Hellwig 2020-02-17 14:54 ` Peter Ujfalusi 2020-02-18 7:26 ` Peter Ujfalusi 2020-02-18 8:28 ` Roger Quadros 2020-02-18 17:22 ` Rob Herring 2020-02-19 14:29 ` Roger Quadros 2020-02-19 15:25 ` Robin Murphy 2020-02-19 15:40 ` Roger Quadros 2020-02-26 11:33 ` Roger Quadros 2020-03-03 8:27 ` Roger Quadros 2020-03-03 14:06 ` Robin Murphy 2020-03-03 19:26 ` Rob Herring 2020-03-04 8:28 ` Roger Quadros
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