From: Grygorii Strashko <grygorii.strashko@xxxxxx>
This patch introduces ARM specific function arm_dt_dma_configure()
which intended to 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 "dam-coherent" properties if supported. The DMA configuration applied
by arm_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: 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>
Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
---
arch/arm/include/asm/prom.h | 3 +++
arch/arm/kernel/devtree.c | 61 +++++++++++++++++++++++++++++++++++++++++++
drivers/of/platform.c | 5 +++-
include/linux/of.h | 2 +-
4 files changed, 69 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h
index b681575..1acb732 100644
--- a/arch/arm/include/asm/prom.h
+++ b/arch/arm/include/asm/prom.h
@@ -11,11 +11,13 @@
#ifndef __ASMARM_PROM_H
#define __ASMARM_PROM_H
+struct device;
#ifdef CONFIG_OF
extern const struct machine_desc *setup_machine_fdt(unsigned int dt_phys);
extern void arm_dt_memblock_reserve(void);
extern void __init arm_dt_init_cpu_maps(void);
+extern void arm_dt_dma_configure(struct device *dev);
#else /* CONFIG_OF */
@@ -26,6 +28,7 @@ static inline const struct machine_desc *setup_machine_fdt(unsigned int dt_phys)
static inline void arm_dt_memblock_reserve(void) { }
static inline void arm_dt_init_cpu_maps(void) { }
+static inline void arm_dt_dma_configure(struct device *dev) { }
#endif /* CONFIG_OF */
#endif /* ASMARM_PROM_H */
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index f751714..926b5dd 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -18,6 +18,9 @@
#include <linux/of_fdt.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
+#include <linux/of_dma.h>
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
#include <asm/cputype.h>
#include <asm/setup.h>
@@ -235,3 +238,61 @@ const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
return mdesc;
}
+
+void arm_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->archdata.dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
+
+ /* Configure DMA mask */
+ dev->dma_mask = kmalloc(sizeof(*dev->dma_mask), GFP_KERNEL);
+ if (!dev->dma_mask)
+ return;
+
+ dma_mask = dma_addr + size - 1;
+
+ ret = arm_dma_set_mask(dev, dma_mask);
+ if (ret < 0) {
+ dev_err(dev, "failed to set DMA mask %#08x\n", dma_mask);
+ kfree(dev->dma_mask);
+ dev->dma_mask = NULL;
+ return;
+ }
+
+ dev_dbg(dev, "dma_pfn_offset(%#08lx) dma_mask(%#016llx)\n",
+ dev->archdata.dma_pfn_offset, *dev->dma_mask);
+
+ if (of_dma_is_coherent(dev->of_node)) {
+ set_dma_ops(dev, &arm_coherent_dma_ops);
+ dev_dbg(dev, "device is dma coherent\n");
+ }
+
+ ret = dma_set_coherent_mask(dev, dma_mask);
+ if (ret < 0) {
+ dev_err(dev, "failed to set coherent DMA mask %#08x\n",
+ dma_mask);
+ }
+}
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 404d1da..97d5533 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -213,10 +213,13 @@ static struct platform_device *of_platform_device_create_pdata(
#if defined(CONFIG_MICROBLAZE)
dev->archdata.dma_mask = 0xffffffffUL;
-#endif
+#elif defined(CONFIG_ARM_LPAE)
+ arm_dt_dma_configure(&dev->dev);
+#else
dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
if (!dev->dev.dma_mask)
dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
+#endif
dev->dev.bus = &platform_bus_type;
dev->dev.platform_data = platform_data;
diff --git a/include/linux/of.h b/include/linux/of.h
index 70c64ba..a321058 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -136,7 +136,7 @@ static inline unsigned long of_read_ulong(const __be32 *cell, int size)
return of_read_number(cell, size);
}
-#if defined(CONFIG_SPARC)
+#if defined(CONFIG_SPARC) || defined(CONFIG_ARM_LPAE)
#include <asm/prom.h>
#endif
--
1.7.9.5
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