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Subject[PATCH v1] of: calculate masks of the device based on dma-range size
Date
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@8bytes.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
---
- apply on top of the series "[PATCH v6 0/7] PCI: get DMA configuration
from parent device" at www.spinics.net/lists/linux-pci/msg38699.html

v1 - updated based on comments. Reverted to original
code for of_dma_get_range() within the of_dma_configure()

drivers/of/device.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 314c8a9..167ad2d 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
@@ -102,6 +103,11 @@ void of_dma_configure(struct device *dev, struct device_node *np)
if (!dev->dma_mask)
dev->dma_mask = &dev->coherent_dma_mask;

+ /*
+ * Use default size to cover 32 bit. Drivers need to set this in DT
+ * to override the same.
+ */
+ size = 1ULL << 32;
ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
if (ret < 0) {
dma_addr = offset = 0;
@@ -128,6 +134,15 @@ 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 ");
--
1.7.9.5


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