iommu: Add DMA window parser, of_get_dma_window()

if IOMMU_SUPPORT

config OF_IOMMU

       def_bool y

       depends on OF

# MSM IOMMU support

config MSM_IOMMU

	bool "MSM IOMMU Support"

obj-$(CONFIG_IOMMU_API) += iommu.o

obj-$(CONFIG_OF_IOMMU)	+= of_iommu.o

obj-$(CONFIG_MSM_IOMMU) += msm_iommu.o msm_iommu_dev.o

obj-$(CONFIG_AMD_IOMMU) += amd_iommu.o amd_iommu_init.o

obj-$(CONFIG_AMD_IOMMU_V2) += amd_iommu_v2.o

/*

 * OF helpers for IOMMU

 *

 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program; if not, write to the Free Software Foundation, Inc.,

 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

 */

#include <linux/export.h>

#include <linux/limits.h>

#include <linux/of.h>

/**

 * of_get_dma_window - Parse *dma-window property and returns 0 if found.

 *

 * @dn: device node

 * @prefix: prefix for property name if any

 * @index: index to start to parse

 * @busno: Returns busno if supported. Otherwise pass NULL

 * @addr: Returns address that DMA starts

 * @size: Returns the range that DMA can handle

 *

 * This supports different formats flexibly. "prefix" can be

 * configured if any. "busno" and "index" are optionally

 * specified. Set 0(or NULL) if not used.

 */

int of_get_dma_window(struct device_node *dn, const char *prefix, int index,

		      unsigned long *busno, dma_addr_t *addr, size_t *size)

{

	const __be32 *dma_window, *end;

	int bytes, cur_index = 0;

	char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX];

	if (!dn || !addr || !size)

		return -EINVAL;

	if (!prefix)

		prefix = "";

	snprintf(propname, sizeof(propname), "%sdma-window", prefix);

	snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix);

	snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix);

	dma_window = of_get_property(dn, propname, &bytes);

	if (!dma_window)

		return -ENODEV;

	end = dma_window + bytes / sizeof(*dma_window);

	while (dma_window < end) {

		u32 cells;

		const void *prop;

		/* busno is one cell if supported */

		if (busno)

			*busno = be32_to_cpup(dma_window++);

		prop = of_get_property(dn, addrname, NULL);

		if (!prop)

			prop = of_get_property(dn, "#address-cells", NULL);

		cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn);

		if (!cells)

			return -EINVAL;

		*addr = of_read_number(dma_window, cells);

		dma_window += cells;

		prop = of_get_property(dn, sizename, NULL);

		cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn);

		if (!cells)

			return -EINVAL;

		*size = of_read_number(dma_window, cells);

		dma_window += cells;

		if (cur_index++ == index)

			break;

	}

	return 0;

}

EXPORT_SYMBOL_GPL(of_get_dma_window);

#ifndef __OF_IOMMU_H

#define __OF_IOMMU_H

#ifdef CONFIG_OF_IOMMU

extern int of_get_dma_window(struct device_node *dn, const char *prefix,

			     int index, unsigned long *busno, dma_addr_t *addr,

			     size_t *size);

#else

static inline int of_get_dma_window(struct device_node *dn, const char *prefix,

			    int index, unsigned long *busno, dma_addr_t *addr,

			    size_t *size)

{

	return -EINVAL;

}

#endif	/* CONFIG_OF_IOMMU */

#endif /* __OF_IOMMU_H */