Re: [PATCH v1] of: calculate masks of the device based on dma-range size

From: Murali Karicheri
Date: Tue Mar 03 2015 - 13:00:42 EST


On 02/25/2015 07:20 PM, Bjorn Helgaas wrote:
[+cc Catalin]

On Wed, Feb 11, 2015 at 12:53:35PM -0500, Murali Karicheri wrote:
This patch update of_dma_configure() API to calculate the
masks (dma_mask and coherent_dma_mask) based on the dma-range
values set in DT for the device. Also limit the mask to lower
of the default mask and mask calculated.

Cc: Joerg Roedel<joro@xxxxxxxxxx>
Cc: Grant Likely<grant.likely@xxxxxxxxxx>
Cc: Rob Herring<robh+dt@xxxxxxxxxx>
Cc: Bjorn Helgaas<bhelgaas@xxxxxxxxxx>
Cc: Will Deacon<will.deacon@xxxxxxx>
Cc: Russell King<linux@xxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann<arnd@xxxxxxxx>
Cc: Suravee Suthikulpanit<Suravee.Suthikulpanit@xxxxxxx>

Signed-off-by: Murali Karicheri<m-karicheri2@xxxxxx>

Applied with Catalin's reviewed-by to pci/iommu for v4.1, thanks!
Bjorn,

Could you point me to this? I didn't see it on pci/iommu of your repo below.

arm-pci git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git (fetch)

a0868495@ula0868495 ~/Project/linux-keystone $ gitlog arm-pci/pci/iommu
dd8a11b0f0d4ed0ad87c8d09e650f354021d7953 arm: dma-mapping: limit IOMMU mapping size
2a101e79dcd8733e3a353b0df2fa384980f94e1e PCI: Update DMA configuration from DT
3fd29d06e9aa92d9a4513e14b2dd3f0d69d4d2b7 of/pci: Add of_pci_dma_configure() to update DMA configuration
8243352097c468f982a9f386cb1f455672b473a2 PCI: Add helper functions pci_get[put]_host_bridge_device()
039f346ac880d4f894425ef6c540f3ff5c1b8dcf of: Fix size when dma-range is not used
2743a957f6a6317be06d02cc93d78bb2a847e427 of: Move of_dma_configure() to device.c to help re-use
f454cd01b5bdffb1bf26a5cddac30439fa5f27a1 of: iommu: Add ptr to OF node arg to of_iommu_configure()
c517d838eb7d07bbe9507871fab3931deccff539 Linux 4.0-rc1

Murali


I agree with Catalin's comment about the "size = 1ULL<< 32" line.
I don't see how that will make a difference, so I dropped it. The
patch I merged is below. Let me know if you think we do need that
line or any other tweaks.

Bjorn

commit a5a1dd69080dfcf53bfd6e179f3db68e824aeaae
Author: Murali Karicheri<m-karicheri2@xxxxxx>
Date: Wed Feb 25 17:21:04 2015 -0600

of: Calculate device DMA masks based on DT dma-range size

Calculate the dma_mask and coherent_dma_mask based on the dma-range values
set in DT for the device.

Limit the mask to lower of the default mask and mask calculated.

Signed-off-by: Murali Karicheri<m-karicheri2@xxxxxx>
Signed-off-by: Bjorn Helgaas<bhelgaas@xxxxxxxxxx>
Reviewed-by: Catalin Marinas<catalin.marinas@xxxxxxx>
CC: Joerg Roedel<joro@xxxxxxxxxx>
CC: Grant Likely<grant.likely@xxxxxxxxxx>
CC: Rob Herring<robh+dt@xxxxxxxxxx>
CC: Will Deacon<will.deacon@xxxxxxx>
CC: Russell King<linux@xxxxxxxxxxxxxxxx>
CC: Arnd Bergmann<arnd@xxxxxxxx>
CC: Suravee Suthikulpanit<Suravee.Suthikulpanit@xxxxxxx>

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 28e743888402..20c1332a0018 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -90,10 +90,11 @@ void of_dma_configure(struct device *dev, struct device_node *np)
struct iommu_ops *iommu;

/*
- * Set default dma-mask to 32 bit. Drivers are expected to setup
- * the correct supported dma_mask.
+ * Set default coherent_dma_mask to 32 bit. Drivers are expected to
+ * setup the correct supported mask.
*/
- dev->coherent_dma_mask = DMA_BIT_MASK(32);
+ if (!dev->coherent_dma_mask)
+ dev->coherent_dma_mask = DMA_BIT_MASK(32);

/*
* Set it to coherent_dma_mask by default if the architecture
@@ -128,6 +129,15 @@ void of_dma_configure(struct device *dev, struct device_node *np)

dev->dma_pfn_offset = offset;

+ /*
+ * Limit coherent and dma mask based on size and default mask
+ * set by the driver.
+ */
+ dev->coherent_dma_mask = min(dev->coherent_dma_mask,
+ DMA_BIT_MASK(ilog2(dma_addr + size)));
+ *dev->dma_mask = min((*dev->dma_mask),
+ DMA_BIT_MASK(ilog2(dma_addr + size)));
+
coherent = of_dma_is_coherent(np);
dev_dbg(dev, "device is%sdma coherent\n",
coherent ? " " : " not ");


--
Murali Karicheri
Linux Kernel, Texas Instruments
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