Commit 591c1ee4 authored by Santosh Shilimkar's avatar Santosh Shilimkar

of: configure the platform device dma parameters

Retrieve DMA configuration from DT and setup platform device's DMA
parameters. The DMA configuration in DT has to be specified using
"dma-ranges" and "dma-coherent" properties if supported.

We setup dma_pfn_offset using "dma-ranges" and dma_coherent_ops
using "dma-coherent" device tree properties.

The set_arch_dma_coherent_ops macro has to be defined by arch if
it supports coherent dma_ops. Otherwise, set_arch_dma_coherent_ops() is
declared as nop.

Cc: Greg Kroah-Hartman <>
Cc: Russell King <>
Cc: Arnd Bergmann <>
Cc: Olof Johansson <>
Cc: Grant Likely <>
Cc: Catalin Marinas <>
Cc: Linus Walleij <>
Reviewed-by: default avatarRob Herring <>
Signed-off-by: default avatarGrygorii Strashko <>
Signed-off-by: default avatarSantosh Shilimkar <>
parent 92ea637e
......@@ -186,6 +186,64 @@ struct platform_device *of_device_alloc(struct device_node *np,
* of_dma_configure - Setup DMA configuration
* @dev: Device to apply DMA configuration
* Try to get devices's DMA configuration from DT and update it
* accordingly.
* In case if platform code need to use own special DMA configuration,it
* can use Platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE event
* to fix up DMA configuration.
static void of_dma_configure(struct platform_device *pdev)
u64 dma_addr, paddr, size;
int ret;
struct device *dev = &pdev->dev;
pdev->archdata.dma_mask = 0xffffffffUL;
* Set default dma-mask to 32 bit. Drivers are expected to setup
* the correct supported dma_mask.
dev->coherent_dma_mask = DMA_BIT_MASK(32);
* Set it to coherent_dma_mask by default if the architecture
* code has not set it.
if (!dev->dma_mask)
dev->dma_mask = &dev->coherent_dma_mask;
* if dma-coherent property exist, call arch hook to setup
* dma coherent operations.
if (of_dma_is_coherent(dev->of_node)) {
dev_dbg(dev, "device is dma coherent\n");
* if dma-ranges property doesn't exist - just return else
* setup the dma offset
ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size);
if (ret < 0) {
dev_dbg(dev, "no dma range information to setup\n");
/* DMA ranges found. Calculate and set dma_pfn_offset */
dev->dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset);
* of_platform_device_create_pdata - Alloc, initialize and register an of_device
* @np: pointer to node to create device for
......@@ -211,12 +269,7 @@ static struct platform_device *of_platform_device_create_pdata(
if (!dev)
return NULL;
dev->archdata.dma_mask = 0xffffffffUL;
dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
if (!dev->dev.dma_mask)
dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
dev->dev.bus = &platform_bus_type;
dev->dev.platform_data = platform_data;
......@@ -123,6 +123,13 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
extern u64 dma_get_required_mask(struct device *dev);
#ifndef set_arch_dma_coherent_ops
static inline int set_arch_dma_coherent_ops(struct device *dev)
return 0;
static inline unsigned int dma_get_max_seg_size(struct device *dev)
return dev->dma_parms ? dev->dma_parms->max_segment_size : 65536;
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