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#include <linux/config.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/string.h>
#include <asm/bootinfo.h>
#include <asm/page.h>
#include <prom.h>
#include <platform.h>
#define DCR 0xb8001004
void __init prom_meminit(void)
{
//char *ptr;
unsigned int memsize;
memsize = 0x02000000; /* Default to 32MB */
/* Check the command line first for a memsize directive */
//ptr = strstr(arcs_cmdline, "mem=");
#if 1
/*now: alway believe DRAM configuration register*/
{
unsigned int DCRvalue = 0;
unsigned int bus_width = 0, chip_sel = 0, row_cnt = 0, col_cnt = 0,bank_cnt = 0;
DCRvalue = ( (*(volatile unsigned int *)DCR));
/*bit 19,0:2 bank; 1: 4 bank*/
switch(DCRvalue & 0x080000)
{
case 0x0:
bank_cnt = 2;
break;
case 0x080000:
bank_cnt = 4;
break;
default:
bank_cnt = 0;
break;
}
/*bit 22~24: colomn count*/
switch(DCRvalue & 0x01C00000)
{
case 0x00000000:
col_cnt = 256;
break;
case 0x00400000:
col_cnt = 512;
break;
case 0x00800000:
col_cnt = 1024;
break;
case 0x00C00000:
col_cnt = 2048;
break;
case 0x01000000:
col_cnt = 4096;
break;
default:
printk("unknow colomn count(0x%x)\n",DCRvalue & 0x01C00000);
break;
}
/*bit 25~26: row count*/
switch(DCRvalue & 0x06000000)
{
case 0x00000000:
row_cnt = 2048;
break;
case 0x02000000:
row_cnt = 4096;
break;
case 0x04000000:
row_cnt = 8192;
break;
case 0x06000000:
row_cnt = 16384;
break;
}
/*bit 27: chip select*/
switch(DCRvalue & 0x08000000)
{
case 0x0:
chip_sel = 1;
break;
case 0x08000000:
chip_sel = 2;
break;
}
/*bit 28~29: bus width*/
switch(DCRvalue & 0x30000000)
{
case 0x0:
bus_width = 8;
break;
case 0x10000000:
bus_width = 16;
break;
case 0x20000000:
bus_width = 32;
break;
default:
printk("bus width is reseved!\n");
break;
}
/*total size(Byte)*/
memsize = (row_cnt * col_cnt *bank_cnt) * (bus_width >> 3) * chip_sel;
}
#endif
/*
* call <add_memory_region> to register boot_mem_map
* add_memory_region(base, size, type);
* type: BOOT_MEM_RAM, BOOT_MEM_ROM_DATA or BOOT_MEM_RESERVED
*/
add_memory_region(0, memsize, BOOT_MEM_RAM);
}
//unsigned long __init prom_free_prom_memory(void)
void prom_free_prom_memory(void)
{
//unsigned long freed = 0;
return;// freed;
}
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