Commit 18308c94 authored by Grygorii Strashko's avatar Grygorii Strashko Committed by Santosh Shilimkar
Browse files

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: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
parent 8febcaa2

drivers/of/address.c

+87 −0
Original line number Diff line number Diff line
@@ -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);

include/linux/of_address.h

+8 −0
Original line number Diff line number Diff line
@@ -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

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