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of: introduce of_dma_get_range() helper

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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>
This commit is contained in:
Grygorii Strashko 2014-04-24 11:30:02 -04:00 committed by Santosh Shilimkar
parent 8febcaa2aa
commit 18308c9472
2 changed files with 95 additions and 0 deletions
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87
drivers/of/address.c
View File

@ -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);

8
include/linux/of_address.h
View File

@ -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