From: Grygorii Strashko <grygorii.strashko@xxxxxx>
Retrieve DMA configuration from DT and setup platform device's DMA
parameters.
The DMA configuration in DT has to be specified using "dma-ranges"
property if supported. The DMA configuration applied
by dt_dma_configure() as following:
- call of_get_dma_range() and get supported DMA range info
(dma_addr, cpu_addr, dma_size);
- if "not found" then fill dma_mask as DMA_BIT_MASK(32)
(this is default behaviour);
- if "failed" then clean up dma_mask (DMA not supported)
- if ok then update devices DMA configuration:
set dma_mask to (dma_addr + dma_size - 1)
set dma_pfn_offset to PFN_DOWN(cpu_addr - dma_addr)
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Olof Johansson <olof@xxxxxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
---
drivers/of/platform.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 72 insertions(+), 3 deletions(-)
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index bd080db..53bb12f 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -187,6 +187,77 @@ struct platform_device *of_device_alloc(struct device_node *np,
EXPORT_SYMBOL(of_device_alloc);
/**
+ * dt_dma_configure - apply default DMA configuration from dt
+ * @dev: Device to apply DMA configuration
+ *
+ * Try to get devices's DMA configuration from DT and apply it.
+ * The DMA configuration is represented in DT by "dma-ranges" property.
+ * It configures:
+ * dma_pfn_offset, dma_mask and coherent_dma_mask.
+ *
+ * In case if DMA configuration can't be acquired from DT the default one is
+ * applied:
+ * dma_pfn_offset = 0,
+ * dma_mask = DMA_BIT_MASK(32)
+ * coherent_dma_mask = DMA_BIT_MASK(32).
+ *
+ * In case if platform code need to use own DMA configuration - it can use
+ * Platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE event to fix up
+ * DMA configuration.
+ */
+static void dt_dma_configure(struct device *dev)
+{
+ dma_addr_t dma_addr;
+ phys_addr_t paddr, size;
+ dma_addr_t dma_mask;
+ int ret;
+
+ /*
+ * if dma-ranges property doesn't exist - use 32 bits DMA mask
+ * by default and don't set skip archdata.dma_pfn_offset
+ */
+ ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size);
+ if (ret == -ENODEV) {
+ dev->coherent_dma_mask = DMA_BIT_MASK(32);
+ if (!dev->dma_mask)
+ dev->dma_mask = &dev->coherent_dma_mask;
+ return;
+ }
+
+ /* if failed - disable DMA for device */
+ if (ret < 0) {
+ dev_err(dev, "failed to configure DMA\n");
+ return;
+ }
+
+ /* DMA ranges found. Calculate and set dma_pfn_offset */
+ dev->dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
+
+ /* Configure DMA mask */
+ dev->dma_mask = &dev->coherent_dma_mask;
+ if (!dev->dma_mask)
+ return;
+
+ dma_mask = dma_addr + size - 1;
+
+ ret = dma_set_mask(dev, dma_mask);
+ if (ret < 0) {
+ dev_err(dev, "failed to set DMA mask %pad\n", &dma_mask);
+ dev->dma_mask = NULL;
+ return;
+ }
+
+ dev_dbg(dev, "dma_pfn_offset(%#08lx) dma_mask(%pad)\n",
+ dev->dma_pfn_offset, dev->dma_mask);
+
+ ret = dma_set_coherent_mask(dev, dma_mask);
+ if (ret < 0) {
+ dev_err(dev, "failed to set coherent DMA mask %pad\n",
+ &dma_mask);
+ }
+}
+
+/**
* of_platform_device_create_pdata - Alloc, initialize and register an of_device
* @np: pointer to node to create device for
* @bus_id: name to assign device
@@ -214,9 +285,7 @@ static struct platform_device *of_platform_device_create_pdata(
#if defined(CONFIG_MICROBLAZE)
dev->archdata.dma_mask = 0xffffffffUL;
#endif
- dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
- if (!dev->dev.dma_mask)
- dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
+ dt_dma_configure(&dev->dev);
dev->dev.bus = &platform_bus_type;
dev->dev.platform_data = platform_data;
--
1.7.9.5
--
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