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 ` dma_mask limited to 32-bits with OF platform device 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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