From: Grygorii Strashko <[email protected]> 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: Russell King <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Olof Johansson <[email protected]> Cc: Grant Likely <[email protected]> Cc: Rob Herring <[email protected]> Signed-off-by: Grygorii Strashko <[email protected]> Signed-off-by: Santosh Shilimkar <[email protected]> --- drivers/dma/of-dma.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/of_dma.h | 8 +++++ 2 files changed, 94 insertions(+) diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c index e8fe9dc..9b51768 100644 --- a/drivers/dma/of-dma.c +++ b/drivers/dma/of-dma.c @@ -17,6 +17,7 @@ #include <linux/slab.h> #include <linux/of.h> #include <linux/of_dma.h> +#include <linux/of_address.h> static LIST_HEAD(of_dma_list); static DEFINE_MUTEX(of_dma_lock); @@ -218,3 +219,88 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, &dma_spec->args[0]); } EXPORT_SYMBOL_GPL(of_dma_simple_xlate); + +/** + * 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-range" 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. + */ +extern int of_dma_get_range(struct device_node *np, dma_addr_t *dma_addr, + phys_addr_t *paddr, phys_addr_t *size) +{ + struct device_node *node = np; + const u32 *ranges = NULL; + int len, naddr, nsize, pna; + int ret = 0; + + 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 + */ + *dma_addr = of_read_number(ranges, naddr); + *paddr = of_translate_dma_address(np, ranges); + if (*paddr == OF_BAD_ADDR) { + pr_err("%s: translation of DMA address(%#08x) to CPU address failed node(%s)\n", + __func__, *dma_addr, np->full_name); + ret = -EINVAL; + } + + *size = of_read_number(ranges + naddr + pna, nsize); + + pr_debug("dma_addr(%08x) cpu_addr(%pa) size(%pa)\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_dma.h b/include/linux/of_dma.h index ae36298..f04171a 100644 --- a/include/linux/of_dma.h +++ b/include/linux/of_dma.h @@ -41,6 +41,9 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np, const char *name); extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, struct of_dma *ofdma); + +extern int of_dma_get_range(struct device_node *np, dma_addr_t *dma_addr, + phys_addr_t *paddr, phys_addr_t *size); #else static inline int of_dma_controller_register(struct device_node *np, struct dma_chan *(*of_dma_xlate) @@ -66,6 +69,11 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s return NULL; } +static inline int of_dma_get_range(struct device_node *np, dma_addr_t *dma_addr, + phys_addr_t *paddr, phys_addr_t *size); +{ + return -ENODEV; +} #endif #endif /* __LINUX_OF_DMA_H */ -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
