u-boot/arch/sandbox/include/asm/io.h
Simon Glass 781adb5710 sandbox: Provide a way to map from host RAM to U-Boot RAM
In many cases, pointers to memory are passed around, and these pointers
refer to U-Boot memory, not host memory. This in itself is not a
problem.

However, in a few places, we cast that pointer back to a ulong (being
a U-Boot memory address). It is possible to convert many of these cases
to avoid this. However there are data structures (e.g. struct
bootm_headers) which use pointers. We could with a lot of effort adjust
the structs and all code that uses them to use ulong instead of pointers.

This seems like an unacceptable cost, since our objective with sandbox
is to minimise the impact on U-Boot code while maximising the features
available to sandbox.

Therefore, create a map_to_sysmem() function which converts from a
pointer to a U-Boot address. This can be used sparingly when needed.

Signed-off-by: Simon Glass <sjg@chromium.org>
2013-05-01 11:17:21 -04:00

55 lines
1.6 KiB
C

/*
* Copyright (c) 2011 The Chromium OS Authors.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* 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., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* Given a physical address and a length, return a virtual address
* that can be used to access the memory range with the caching
* properties specified by "flags".
*/
#define MAP_NOCACHE (0)
#define MAP_WRCOMBINE (0)
#define MAP_WRBACK (0)
#define MAP_WRTHROUGH (0)
void *map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags);
/*
* Take down a mapping set up by map_physmem().
*/
static inline void unmap_physmem(void *vaddr, unsigned long flags)
{
}
/* For sandbox, we want addresses to point into our RAM buffer */
static inline void *map_sysmem(phys_addr_t paddr, unsigned long len)
{
return map_physmem(paddr, len, MAP_WRBACK);
}
static inline void unmap_sysmem(const void *vaddr)
{
}
/* Map from a pointer to our RAM buffer */
phys_addr_t map_to_sysmem(void *ptr);