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/*
* (C) Copyright 2003
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* 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
*/
#include <common.h>
#include <command.h>
#include <asm/addrspace.h>
#include <asm/inca-ip.h>
static ulong max_sdram_size(void)
{
/* The only supported SDRAM data width is 16bit.
*/
#define CFG_DW 2
/* The only supported number of SDRAM banks is 4.
*/
#define CFG_NB 4
ulong cfgpb0 = *INCA_IP_SDRAM_MC_CFGPB0;
int cols = cfgpb0 & 0xF;
int rows = (cfgpb0 & 0xF0) >> 4;
ulong size = (1 << (rows + cols)) * CFG_DW * CFG_NB;
return size;
}
/*
* Check memory range for valid RAM. A simple memory test determines
* the actually available RAM size between addresses `base' and
* `base + maxsize'. Some (not all) hardware errors are detected:
* - short between address lines
* - short between data lines
*/
static long int dram_size(long int *base, long int maxsize)
{
volatile long int *addr;
ulong cnt, val;
ulong save[32]; /* to make test non-destructive */
unsigned char i = 0;
for (cnt = (maxsize / sizeof (long)) >> 1; cnt > 0; cnt >>= 1) {
addr = base + cnt; /* pointer arith! */
save[i++] = *addr;
*addr = ~cnt;
}
/* write 0 to base address */
addr = base;
save[i] = *addr;
*addr = 0;
/* check at base address */
if ((val = *addr) != 0) {
*addr = save[i];
return (0);
}
for (cnt = 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
addr = base + cnt; /* pointer arith! */
val = *addr;
*addr = save[--i];
if (val != (~cnt)) {
return (cnt * sizeof (long));
}
}
return (maxsize);
}
long int initdram(int board_type)
{
int rows, cols, best_val = *INCA_IP_SDRAM_MC_CFGPB0;
ulong size, max_size = 0;
ulong our_address;
asm volatile ("move %0, $25" : "=r" (our_address) :);
/* Can't probe for RAM size unless we are running from Flash.
*/
if (PHYSADDR(our_address) < PHYSADDR(PHYS_FLASH_1))
{
return max_sdram_size();
}
for (cols = 0x8; cols <= 0xC; cols++)
{
for (rows = 0xB; rows <= 0xD; rows++)
{
*INCA_IP_SDRAM_MC_CFGPB0 = (0x14 << 8) |
(rows << 4) | cols;
size = dram_size((ulong *)CFG_SDRAM_BASE,
max_sdram_size());
if (size > max_size)
{
best_val = *INCA_IP_SDRAM_MC_CFGPB0;
max_size = size;
}
}
}
*INCA_IP_SDRAM_MC_CFGPB0 = best_val;
return max_size;
}
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