Merge tag 'dt-dma-properties-for-arm' of git://git.kernel.org/pub/scm/linux/kernel/git/ssantosh/linux-keystone into devel-stable

DT support for 'dma-ranges'and 'dma-coherent' properties with ARM updates

- The 'dma-ranges' helps to take care of few DMAable system memory
        restrictions by use of dma_pfn_offset which is maintained per
        device. Arch code then uses it for dma address translations for such
        cases. We update the dma_pfn_offset accordingly during DT the device
        creation process.
- The 'dma-coherent' property is used to setup arch's coherent dma_ops.

7 files changed, 218 insertions, 9 deletions

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index e701a4d9aa59..c45b61a4b4a5 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -58,21 +58,37 @@ static inline int dma_set_mask(struct device *dev, u64 mask)
 #ifndef __arch_pfn_to_dma
 static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn)
 {
+        if (dev)
+                pfn -= dev->dma_pfn_offset;
         return (dma_addr_t)__pfn_to_bus(pfn);
 }
 
 static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr)
 {
-        return __bus_to_pfn(addr);
+        unsigned long pfn = __bus_to_pfn(addr);
+
+        if (dev)
+                pfn += dev->dma_pfn_offset;
+
+        return pfn;
 }
 
 static inline void *dma_to_virt(struct device *dev, dma_addr_t addr)
 {
+        if (dev) {
+                unsigned long pfn = dma_to_pfn(dev, addr);
+
+                return phys_to_virt(__pfn_to_phys(pfn));
+        }
+
         return (void *)__bus_to_virt((unsigned long)addr);
 }
 
 static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
 {
+        if (dev)
+                return pfn_to_dma(dev, virt_to_pfn(addr));
+
         return (dma_addr_t)__virt_to_bus((unsigned long)(addr));
 }
 
@@ -105,6 +121,13 @@ static inline unsigned long dma_max_pfn(struct device *dev)
 }
 #define dma_max_pfn(dev) dma_max_pfn(dev)
 
+static inline int set_arch_dma_coherent_ops(struct device *dev)
+{
+        set_dma_ops(dev, &arm_coherent_dma_ops);
+        return 0;
+}
+#define set_arch_dma_coherent_ops(dev)  set_arch_dma_coherent_ops(dev)
+
 static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
 {
         unsigned int offset = paddr & ~PAGE_MASK;
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 6b00be1f971e..18e98dfb73fc 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -885,7 +885,7 @@ static void dma_cache_maint_page(struct page *page, unsigned long offset,
 static void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
         size_t size, enum dma_data_direction dir)
 {
-        unsigned long paddr;
+        phys_addr_t paddr;
 
         dma_cache_maint_page(page, off, size, dir, dmac_map_area);
 
@@ -901,7 +901,7 @@ static void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
 static void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
         size_t size, enum dma_data_direction dir)
 {
-        unsigned long paddr = page_to_phys(page) + off;
+        phys_addr_t paddr = page_to_phys(page) + off;
 
         /* FIXME: non-speculating: not required */
         /* don't bother invalidating if DMA to device */
diff --git a/drivers/of/address.c b/drivers/of/address.c
index cb4242a69cd5..d244b2859aac 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -721,3 +721,113 @@ void __iomem *of_iomap(struct device_node *np, int index)
         return ioremap(res.start, resource_size(&res));
 }
 EXPORT_SYMBOL(of_iomap);
+
+/**
+ * of_dma_get_range - Get DMA range info
+ * @np:         device node to get DMA range info
+ * @dma_addr:   pointer to store initial DMA address of DMA range
+ * @paddr:      pointer to store initial CPU address of DMA range
+ * @size:       pointer to store size of DMA range
+ *
+ * Look in bottom up direction for the first "dma-ranges" property
+ * and parse it.
+ *  dma-ranges format:
+ *      DMA addr (dma_addr)     : naddr cells
+ *      CPU addr (phys_addr_t)  : pna cells
+ *      size                    : nsize cells
+ *
+ * It returns -ENODEV if "dma-ranges" property was not found
+ * for this device in DT.
+ */
+int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *size)
+{
+        struct device_node *node = of_node_get(np);
+        const __be32 *ranges = NULL;
+        int len, naddr, nsize, pna;
+        int ret = 0;
+        u64 dmaaddr;
+
+        if (!node)
+                return -EINVAL;
+
+        while (1) {
+                naddr = of_n_addr_cells(node);
+                nsize = of_n_size_cells(node);
+                node = of_get_next_parent(node);
+                if (!node)
+                        break;
+
+                ranges = of_get_property(node, "dma-ranges", &len);
+
+                /* Ignore empty ranges, they imply no translation required */
+                if (ranges && len > 0)
+                        break;
+
+                /*
+                 * At least empty ranges has to be defined for parent node if
+                 * DMA is supported
+                 */
+                if (!ranges)
+                        break;
+        }
+
+        if (!ranges) {
+                pr_debug("%s: no dma-ranges found for node(%s)\n",
+                         __func__, np->full_name);
+                ret = -ENODEV;
+                goto out;
+        }
+
+        len /= sizeof(u32);
+
+        pna = of_n_addr_cells(node);
+
+        /* dma-ranges format:
+         * DMA addr     : naddr cells
+         * CPU addr     : pna cells
+         * size         : nsize cells
+         */
+        dmaaddr = of_read_number(ranges, naddr);
+        *paddr = of_translate_dma_address(np, ranges);
+        if (*paddr == OF_BAD_ADDR) {
+                pr_err("%s: translation of DMA address(%pad) to CPU address failed node(%s)\n",
+                       __func__, dma_addr, np->full_name);
+                ret = -EINVAL;
+                goto out;
+        }
+        *dma_addr = dmaaddr;
+
+        *size = of_read_number(ranges + naddr + pna, nsize);
+
+        pr_debug("dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",
+                 *dma_addr, *paddr, *size);
+
+out:
+        of_node_put(node);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(of_dma_get_range);
+
+/**
+ * of_dma_is_coherent - Check if device is coherent
+ * @np: device node
+ *
+ * It returns true if "dma-coherent" property was found
+ * for this device in DT.
+ */
+bool of_dma_is_coherent(struct device_node *np)
+{
+        struct device_node *node = of_node_get(np);
+
+        while (node) {
+                if (of_property_read_bool(node, "dma-coherent")) {
+                        of_node_put(node);
+                        return true;
+                }
+                node = of_get_next_parent(node);
+        }
+        of_node_put(node);
+        return false;
+}
+EXPORT_SYMBOL_GPL(of_dma_is_coherent);
\ No newline at end of file
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index bd47fbc53dc9..4e91583a3908 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -189,6 +189,64 @@ struct platform_device *of_device_alloc(struct device_node *np,
 EXPORT_SYMBOL(of_device_alloc);
 
 /**
+ * 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;
+
+#if defined(CONFIG_MICROBLAZE)
+        pdev->archdata.dma_mask = 0xffffffffUL;
+#endif
+
+        /*
+         * 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)) {
+                set_arch_dma_coherent_ops(dev);
+                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");
+                return;
+        }
+
+        /* 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
  * @bus_id: name to assign device
@@ -213,12 +271,7 @@ static struct platform_device *of_platform_device_create_pdata(
         if (!dev)
                 return NULL;
 
-#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;
+        of_dma_configure(dev);
         dev->dev.bus = &platform_bus_type;
         dev->dev.platform_data = platform_data;
 
diff --git a/include/linux/device.h b/include/linux/device.h
index d1d1c055b48e..460ebad15109 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -685,6 +685,7 @@ struct acpi_dev_node {
  * @coherent_dma_mask: Like dma_mask, but for alloc_coherent mapping as not all
  *              hardware supports 64-bit addresses for consistent allocations
  *              such descriptors.
+ * @dma_pfn_offset: offset of DMA memory range relatively of RAM
  * @dma_parms:  A low level driver may set these to teach IOMMU code about
  *              segment limitations.
  * @dma_pools:  Dma pools (if dma'ble device).
@@ -750,6 +751,7 @@ struct device {
                                              not all hardware supports
                                              64 bit addresses for consistent
                                              allocations such descriptors. */
+        unsigned long   dma_pfn_offset;
 
         struct device_dma_parameters *dma_parms;
 
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index fd4aee29ad10..c7d9b1b14ce7 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -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;
+}
+#endif
+
 static inline unsigned int dma_get_max_seg_size(struct device *dev)
 {
         return dev->dma_parms ? dev->dma_parms->max_segment_size : 65536;
diff --git a/include/linux/of_address.h b/include/linux/of_address.h
index 5f6ed6b182b8..839a3521b28e 100644
--- a/include/linux/of_address.h
+++ b/include/linux/of_address.h
@@ -63,6 +63,9 @@ extern int of_pci_range_parser_init(struct of_pci_range_parser *parser,
 extern struct of_pci_range *of_pci_range_parser_one(
                                         struct of_pci_range_parser *parser,
                                         struct of_pci_range *range);
+extern int of_dma_get_range(struct device_node *np, u64 *dma_addr,
+                                u64 *paddr, u64 *size);
+extern bool of_dma_is_coherent(struct device_node *np);
 #else /* CONFIG_OF_ADDRESS */
 static inline struct device_node *of_find_matching_node_by_address(
                                         struct device_node *from,
@@ -90,6 +93,17 @@ static inline struct of_pci_range *of_pci_range_parser_one(
 {
         return NULL;
 }
+
+static inline int of_dma_get_range(struct device_node *np, u64 *dma_addr,
+                                u64 *paddr, u64 *size)
+{
+        return -ENODEV;
+}
+
+static inline bool of_dma_is_coherent(struct device_node *np)
+{
+        return false;
+}
 #endif /* CONFIG_OF_ADDRESS */
 
 #ifdef CONFIG_OF