Hexagon: Provide DMA implementation

/*

 * DMA operations for the Hexagon architecture

 *

 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.

 *

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

 * it under the terms of the GNU General Public License version 2 and

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

 *

 * This program is distributed in the hope that 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 Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

#ifndef _ASM_DMA_MAPPING_H

#define _ASM_DMA_MAPPING_H

#include <linux/types.h>

#include <linux/cache.h>

#include <linux/mm.h>

#include <linux/scatterlist.h>

#include <linux/dma-mapping.h>

#include <linux/dma-debug.h>

#include <linux/dma-attrs.h>

#include <asm/io.h>

struct device;

extern int bad_dma_address;

extern struct dma_map_ops *dma_ops;

#define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)

#define dma_free_noncoherent(d, s, v, h) dma_free_coherent(d, s, v, h)

static inline struct dma_map_ops *get_dma_ops(struct device *dev)

{

	if (unlikely(dev == NULL))

		return NULL;

	return dma_ops;

}

extern int dma_supported(struct device *dev, u64 mask);

extern int dma_set_mask(struct device *dev, u64 mask);

extern int dma_is_consistent(struct device *dev, dma_addr_t dma_handle);

extern void dma_cache_sync(struct device *dev, void *vaddr, size_t size,

			   enum dma_data_direction direction);

#include <asm-generic/dma-mapping-common.h>

static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)

{

	if (!dev->dma_mask)

		return 0;

	return addr + size - 1 <= *dev->dma_mask;

}

static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)

{

	struct dma_map_ops *dma_ops = get_dma_ops(dev);

	if (dma_ops->mapping_error)

		return dma_ops->mapping_error(dev, dma_addr);

	return (dma_addr == bad_dma_address);

}

static inline void *dma_alloc_coherent(struct device *dev, size_t size,

				       dma_addr_t *dma_handle, gfp_t flag)

{

	void *ret;

	struct dma_map_ops *ops = get_dma_ops(dev);

	BUG_ON(!dma_ops);

	ret = ops->alloc_coherent(dev, size, dma_handle, flag);

	debug_dma_alloc_coherent(dev, size, *dma_handle, ret);

	return ret;

}

static inline void dma_free_coherent(struct device *dev, size_t size,

				     void *cpu_addr, dma_addr_t dma_handle)

{

	struct dma_map_ops *dma_ops = get_dma_ops(dev);

	BUG_ON(!dma_ops);

	dma_ops->free_coherent(dev, size, cpu_addr, dma_handle);

	debug_dma_free_coherent(dev, size, cpu_addr, dma_handle);

}

#endif

/*

 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.

 *

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

 * it under the terms of the GNU General Public License version 2 and

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

 *

 * This program is distributed in the hope that 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 Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

#ifndef _ASM_DMA_H

#define _ASM_DMA_H

#include <asm/io.h>

#define MAX_DMA_CHANNELS 1

#define MAX_DMA_ADDRESS  (PAGE_OFFSET)

extern size_t hexagon_coherent_pool_size;

#endif

/*

 * DMA implementation for Hexagon

 *

 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.

 *

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

 * it under the terms of the GNU General Public License version 2 and

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

 *

 * This program is distributed in the hope that 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 Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

#include <linux/dma-mapping.h>

#include <linux/bootmem.h>

#include <linux/genalloc.h>

#include <asm/dma-mapping.h>

struct dma_map_ops *dma_ops;

EXPORT_SYMBOL(dma_ops);

int bad_dma_address;  /*  globals are automatically initialized to zero  */

int dma_supported(struct device *dev, u64 mask)

{

	if (mask == DMA_BIT_MASK(32))

		return 1;

	else

		return 0;

}

EXPORT_SYMBOL(dma_supported);

int dma_set_mask(struct device *dev, u64 mask)

{

	if (!dev->dma_mask || !dma_supported(dev, mask))

		return -EIO;

	*dev->dma_mask = mask;

	return 0;

}

EXPORT_SYMBOL(dma_set_mask);

static struct gen_pool *coherent_pool;

/* Allocates from a pool of uncached memory that was reserved at boot time */

void *hexagon_dma_alloc_coherent(struct device *dev, size_t size,

				 dma_addr_t *dma_addr, gfp_t flag)

{

	void *ret;

	if (coherent_pool == NULL) {

		coherent_pool = gen_pool_create(PAGE_SHIFT, -1);

		if (coherent_pool == NULL)

			panic("Can't create %s() memory pool!", __func__);

		else

			gen_pool_add(coherent_pool,

				(PAGE_OFFSET + (max_low_pfn << PAGE_SHIFT)),

				hexagon_coherent_pool_size, -1);

	}

	ret = (void *) gen_pool_alloc(coherent_pool, size);

	if (ret) {

		memset(ret, 0, size);

		*dma_addr = (dma_addr_t) (ret - PAGE_OFFSET);

	} else

		*dma_addr = ~0;

	return ret;

}

static void hexagon_free_coherent(struct device *dev, size_t size, void *vaddr,

				  dma_addr_t dma_addr)

{

	gen_pool_free(coherent_pool, (unsigned long) vaddr, size);

}

static int check_addr(const char *name, struct device *hwdev,

		      dma_addr_t bus, size_t size)

{

	if (hwdev && hwdev->dma_mask && !dma_capable(hwdev, bus, size)) {

		if (*hwdev->dma_mask >= DMA_BIT_MASK(32))

			printk(KERN_ERR

				"%s: overflow %Lx+%zu of device mask %Lx\n",

				name, (long long)bus, size,

				(long long)*hwdev->dma_mask);

		return 0;

	}

	return 1;

}

static int hexagon_map_sg(struct device *hwdev, struct scatterlist *sg,

			  int nents, enum dma_data_direction dir,

			  struct dma_attrs *attrs)

{

	struct scatterlist *s;

	int i;

	WARN_ON(nents == 0 || sg[0].length == 0);

	for_each_sg(sg, s, nents, i) {

		s->dma_address = sg_phys(s);

		if (!check_addr("map_sg", hwdev, s->dma_address, s->length))

			return 0;

		s->dma_length = s->length;

		flush_dcache_range(PAGE_OFFSET + s->dma_address,

				   PAGE_OFFSET + s->dma_address + s->length);

	}

	return nents;

}

/*

 * address is virtual

 */

static inline void dma_sync(void *addr, size_t size,

			    enum dma_data_direction dir)

{

	switch (dir) {

	case DMA_TO_DEVICE:

		hexagon_clean_dcache_range((unsigned long) addr,

		(unsigned long) addr + size);

		break;

	case DMA_FROM_DEVICE:

		hexagon_inv_dcache_range((unsigned long) addr,

		(unsigned long) addr + size);

		break;

	case DMA_BIDIRECTIONAL:

		flush_dcache_range((unsigned long) addr,

		(unsigned long) addr + size);

		break;

	default:

		BUG();

	}

}

static inline void *dma_addr_to_virt(dma_addr_t dma_addr)

{

	return phys_to_virt((unsigned long) dma_addr);

}

/**

 * hexagon_map_page() - maps an address for device DMA

 * @dev:	pointer to DMA device

 * @page:	pointer to page struct of DMA memory

 * @offset:	offset within page

 * @size:	size of memory to map

 * @dir:	transfer direction

 * @attrs:	pointer to DMA attrs (not used)

 *

 * Called to map a memory address to a DMA address prior

 * to accesses to/from device.

 *

 * We don't particularly have many hoops to jump through

 * so far.  Straight translation between phys and virtual.

 *

 * DMA is not cache coherent so sync is necessary; this

 * seems to be a convenient place to do it.

 *

 */

static dma_addr_t hexagon_map_page(struct device *dev, struct page *page,

				   unsigned long offset, size_t size,

				   enum dma_data_direction dir,

				   struct dma_attrs *attrs)

{

	dma_addr_t bus = page_to_phys(page) + offset;

	WARN_ON(size == 0);

	if (!check_addr("map_single", dev, bus, size))

		return bad_dma_address;

	dma_sync(dma_addr_to_virt(bus), size, dir);

	return bus;

}

static void hexagon_sync_single_for_cpu(struct device *dev,

					dma_addr_t dma_handle, size_t size,

					enum dma_data_direction dir)

{

	dma_sync(dma_addr_to_virt(dma_handle), size, dir);

}

static void hexagon_sync_single_for_device(struct device *dev,

					dma_addr_t dma_handle, size_t size,

					enum dma_data_direction dir)

{

	dma_sync(dma_addr_to_virt(dma_handle), size, dir);

}

struct dma_map_ops hexagon_dma_ops = {

	.alloc_coherent	= hexagon_dma_alloc_coherent,

	.free_coherent	= hexagon_free_coherent,

	.map_sg		= hexagon_map_sg,

	.map_page	= hexagon_map_page,

	.sync_single_for_cpu = hexagon_sync_single_for_cpu,

	.sync_single_for_device = hexagon_sync_single_for_device,

	.is_phys	= 1,

};

void __init hexagon_dma_init(void)

{

	if (dma_ops)

		return;

	dma_ops = &hexagon_dma_ops;

}