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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2014 Kevin Cernekee <cernekee@gmail.com>
*/
#include <linux/device.h>
#include <linux/dma-direction.h>
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/of.h>
#include <linux/pci.h>
#include <linux/types.h>
#include <dma-coherence.h>
/*
* BCM3384 has configurable address translation windows which allow the
* peripherals' DMA addresses to be different from the Zephyr-visible
* physical addresses. e.g. usb_dma_addr = zephyr_pa ^ 0x08000000
*
* If our DT "memory" node has a "dma-xor-mask" property we will enable this
* translation using the provided offset.
*/
static u32 bcm3384_dma_xor_mask;
static u32 bcm3384_dma_xor_limit = 0xffffffff;
/*
* PCI collapses the memory hole at 0x10000000 - 0x1fffffff.
* On systems with a dma-xor-mask, this range is guaranteed to live above
* the dma-xor-limit.
*/
#define BCM3384_MEM_HOLE_PA 0x10000000
#define BCM3384_MEM_HOLE_SIZE 0x10000000
static dma_addr_t bcm3384_phys_to_dma(struct device *dev, phys_addr_t pa)
{
if (dev && dev_is_pci(dev) &&
pa >= (BCM3384_MEM_HOLE_PA + BCM3384_MEM_HOLE_SIZE))
return pa - BCM3384_MEM_HOLE_SIZE;
if (pa <= bcm3384_dma_xor_limit)
return pa ^ bcm3384_dma_xor_mask;
return pa;
}
dma_addr_t plat_map_dma_mem(struct device *dev, void *addr, size_t size)
{
return bcm3384_phys_to_dma(dev, virt_to_phys(addr));
}
dma_addr_t plat_map_dma_mem_page(struct device *dev, struct page *page)
{
return bcm3384_phys_to_dma(dev, page_to_phys(page));
}
unsigned long plat_dma_addr_to_phys(struct device *dev, dma_addr_t dma_addr)
{
if (dev && dev_is_pci(dev) &&
dma_addr >= BCM3384_MEM_HOLE_PA)
return dma_addr + BCM3384_MEM_HOLE_SIZE;
if ((dma_addr ^ bcm3384_dma_xor_mask) <= bcm3384_dma_xor_limit)
return dma_addr ^ bcm3384_dma_xor_mask;
return dma_addr;
}
static int __init bcm3384_init_dma_xor(void)
{
struct device_node *np = of_find_node_by_type(NULL, "memory");
if (!np)
return 0;
of_property_read_u32(np, "dma-xor-mask", &bcm3384_dma_xor_mask);
of_property_read_u32(np, "dma-xor-limit", &bcm3384_dma_xor_limit);
of_node_put(np);
return 0;
}
arch_initcall(bcm3384_init_dma_xor);
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