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.

2 files changed, 169 insertions, 6 deletions

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;