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authorGrygorii Strashko <grygorii.strashko@ti.com>2014-04-24 19:30:02 +0400
committerSantosh Shilimkar <santosh.shilimkar@ti.com>2014-05-06 02:11:13 +0400
commit18308c94723e162ed121942335bc186e66820a7a (patch)
tree48ac9d3721d820bdace974332f3925cc5dc2c02b /drivers/of/address.c
parent8febcaa2aac184d7e729acb75e9c4b80b04ad1b9 (diff)
downloadlinux-18308c94723e162ed121942335bc186e66820a7a.tar.xz
of: introduce of_dma_get_range() helper
The of_dma_get_range() allows to find "dma-range" property for the specified device and parse it. dma-ranges format: DMA addr (dma_addr) : naddr cells CPU addr (phys_addr_t) : pna cells size : nsize cells Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Olof Johansson <olof@lixom.net> Cc: Grant Likely <grant.likely@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Diffstat (limited to 'drivers/of/address.c')
-rw-r--r--drivers/of/address.c87
1 files changed, 87 insertions, 0 deletions
diff --git a/drivers/of/address.c b/drivers/of/address.c
index cb4242a69cd5..c54baee87d93 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -721,3 +721,90 @@ 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);