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ARC: [Review] Multi-platform image #6: cpu-to-dma-addr optional

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All the current platforms can work with 0x8000_0000 based dma_addr_t
since the Bus Bridges typically ignore the top bit (the only excpetion
was Angel4 PCI-AHB bridge which we no longer care for).
That way we don't need plat-specific cpu-addr to bus-addr conversion.

Hooks still provided - just in case a platform has an obscure device
which say needs 0 based bus address.

That way <asm/dma_mapping.h> no longer needs to unconditinally include
<plat/dma_addr.h>

Also verfied that on Angel4 board, other peripherals (IDE-disk / EMAC)
work fine with 0x8000_0000 based dma addresses.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Vineet Gupta
2013-01-22 16:53:57 +05:30
parent decae9d3e8
commit fc7943d29e
3 changed files with 20 additions and 45 deletions
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45
arch/arc/plat-arcfpga/include/plat/dma_addr.h
View File

@@ -1,45 +0,0 @@
/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* vineetg: Feb 2009
* -For AA4 board, kernel to DMA address APIs
*/
/*
* kernel addresses are 0x800_000 based, while Bus addr are 0 based
*/
#ifndef __PLAT_DMA_ADDR_H
#define __PLAT_DMA_ADDR_H
#include <linux/device.h>
static inline unsigned long plat_dma_addr_to_kernel(struct device *dev,
dma_addr_t dma_addr)
{
return dma_addr + PAGE_OFFSET;
}
static inline dma_addr_t plat_kernel_addr_to_dma(struct device *dev, void *ptr)
{
unsigned long addr = (unsigned long)ptr;
/*
* To Catch buggy drivers which can call DMA map API with kernel vaddr
* i.e. for buffers alloc via vmalloc or ioremap which are not
* gaurnateed to be PHY contiguous and hence unfit for DMA anyways.
* On ARC kernel virtual address is 0x7000_0000 to 0x7FFF_FFFF, so
* ideally we want to check this range here, but our implementation is
* better as it checks for even worse user virtual address as well.
*/
if (likely(addr >= PAGE_OFFSET))
return addr - PAGE_OFFSET;
BUG();
return addr;
}
#endif