openwrtv3/target/linux/adm5120-2.6/files/arch/mips/adm5120/memory.c

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/*
* $Id$
*
* Copyright (C) 2007 OpenWrt.org
* Copyright (C) 2007 Gabor Juhos <juhosg@freemail.hu>
*
* 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., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#include <linux/init.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <asm/bootinfo.h>
#include <asm/addrspace.h>
#include <asm/mach-adm5120/adm5120_info.h>
#include <asm/mach-adm5120/adm5120_defs.h>
#include <asm/mach-adm5120/adm5120_switch.h>
#include <asm/mach-adm5120/adm5120_mpmc.h>
#define SWITCH_READ(r) *(u32 *)(KSEG1ADDR(ADM5120_SWITCH_BASE)+(r))
#define SWITCH_WRITE(r,v) *(u32 *)(KSEG1ADDR(ADM5120_SWITCH_BASE)+(r))=(v)
#define MPMC_READ(r) *(u32 *)(KSEG1ADDR(ADM5120_SWITCH_BASE)+(r))
#define MPMC_WRITE(r,v) *(u32 *)(KSEG1ADDR(ADM5120_SWITCH_BASE)+(r))=(v)
#if 1
# define mem_dbg(f, a...) printk("mem_detect: " f, ## a)
#else
# define mem_dbg(f, a...)
#endif
#define MEM_WR_DELAY 10000 /* 0.01 usec */
unsigned long adm5120_memsize;
static int __init mem_check_pattern(u8 *addr, unsigned long offs)
{
volatile u32 *p1 = (volatile u32 *)addr;
volatile u32 *p2 = (volatile u32 *)(addr+offs);
u32 t,u,v;
/* save original value */
t = *p1;
u = *p2;
if (t != u)
return 0;
v = 0x55555555;
if (u == v)
v = 0xAAAAAAAA;
mem_dbg("write 0x%08lX to 0x%08lX\n", v, (unsigned long)p1);
*p1 = v;
mem_dbg("delay %d ns\n", MEM_WR_DELAY);
adm5120_ndelay(MEM_WR_DELAY);
u = *p2;
mem_dbg("pattern at 0x%08lX is 0x%08lX\n", (unsigned long)p2, u);
/* restore original value */
*p1 = t;
return (v == u);
}
static void __init adm5120_detect_memsize(void)
{
u32 memctrl;
u32 size, maxsize;
u8 *p;
memctrl = SWITCH_READ(SWITCH_REG_MEMCTRL);
switch (memctrl & MEMCTRL_SDRS_MASK) {
case MEMCTRL_SDRS_4M:
maxsize = 4 << 20;
break;
case MEMCTRL_SDRS_8M:
maxsize = 8 << 20;
break;
case MEMCTRL_SDRS_16M:
maxsize = 16 << 20;
break;
default:
maxsize = 64 << 20;
break;
}
/* disable buffers for both SDRAM banks */
mem_dbg("disable buffers for both banks\n");
MPMC_WRITE(MPMC_REG_DC0, MPMC_READ(MPMC_REG_DC0) & ~DC_BE);
MPMC_WRITE(MPMC_REG_DC1, MPMC_READ(MPMC_REG_DC1) & ~DC_BE);
mem_dbg("checking for %ldMB chip in 1st bank\n", maxsize >> 20);
/* detect size of the 1st SDRAM bank */
p = (u8 *)KSEG1ADDR(0);
for (size = 2<<20; size <= (maxsize >> 1); size <<= 1) {
if (mem_check_pattern(p, size)) {
/* mirrored address */
mem_dbg("mirrored data found at offset 0x%lX\n", size);
break;
}
}
mem_dbg("chip size in 1st bank is %ldMB\n", size >> 20);
adm5120_memsize = size;
if (size != maxsize)
/* 2nd bank is not supported */
goto out;
if ((memctrl & MEMCTRL_SDR1_ENABLE) == 0)
/* 2nd bank is disabled */
goto out;
/*
* some bootloaders enable 2nd bank, even if the 2nd SDRAM chip
* are missing.
*/
mem_dbg("check presence of 2nd bank\n");
p = (u8 *)KSEG1ADDR(maxsize+size-4);
if (mem_check_pattern(p, 0)) {
adm5120_memsize += size;
}
if (maxsize != size) {
/* adjusting MECTRL register */
memctrl &= ~(MEMCTRL_SDRS_MASK);
switch (size>>20) {
case 4:
memctrl |= MEMCTRL_SDRS_4M;
break;
case 8:
memctrl |= MEMCTRL_SDRS_8M;
break;
case 16:
memctrl |= MEMCTRL_SDRS_16M;
break;
default:
memctrl |= MEMCTRL_SDRS_64M;
break;
}
SWITCH_WRITE(SWITCH_REG_MEMCTRL, memctrl);
}
out:
/* reenable buffer for both SDRAM banks */
mem_dbg("enable buffers for both banks\n");
MPMC_WRITE(MPMC_REG_DC0, MPMC_READ(MPMC_REG_DC0) | DC_BE);
MPMC_WRITE(MPMC_REG_DC1, MPMC_READ(MPMC_REG_DC1) | DC_BE);
mem_dbg("%dx%ldMB memory found\n", (adm5120_memsize == size) ? 1 : 2 ,
size >>20);
}
void __init adm5120_mem_init(void)
{
adm5120_detect_memsize();
add_memory_region(0, adm5120_memsize, BOOT_MEM_RAM);
}