diff options
| -rw-r--r-- | drivers/of/address.c | 87 | ||||
| -rw-r--r-- | include/linux/of_address.h | 8 |
2 files changed, 95 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); diff --git a/include/linux/of_address.h b/include/linux/of_address.h index 5f6ed6b182b8..4d7b325af2ca 100644 --- a/include/linux/of_address.h +++ b/include/linux/of_address.h @@ -63,6 +63,8 @@ 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); #else /* CONFIG_OF_ADDRESS */ static inline struct device_node *of_find_matching_node_by_address( struct device_node *from, @@ -90,6 +92,12 @@ 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; +} #endif /* CONFIG_OF_ADDRESS */ #ifdef CONFIG_OF |
