utils.c

来自「一个2.4.21版本的嵌入式linux内核」· C语言 代码 · 共 70 行

/*
 *
 *
 *
 *
 */
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/module.h>
#include <asm/io.h>
#include "utils.h"


#define  miu_chan_cfg(x)      ((volatile unsigned long  *)(0xbff40000+x*4))       /* for andros */

int mbsize[8] = {1,2,4,8,16,32,64,128};

unsigned long get_mem_avail(void) {

    unsigned long  cfg[10],i,total_mem=0;

	for(i=0;i<10;i++)  
		cfg[i] = *miu_chan_cfg(i); 

	for(i=0;i<10;i++){
		if(cfg[i]==0x1fc160c2) continue;                           // skip empties 
		if(   ( (cfg[i]>>12) & 0xf )   <=  0xb ) continue;         // skip roms
        total_mem += mbsize[(cfg[i]>>16)&0x7] *1024*1024;
	}
    return total_mem;
}




static ulong* buffer_ptr = NULL;
static ulong buffer_size = 0;

ulong* get_reserved_buffer(void) {return KSEG0ADDR(buffer_ptr);}
ulong* get_reserved_buffer_virtual(void) {return (ulong*)ReservedMemVirtualAddr;}
ulong get_reserved_buffer_size(void) {return buffer_size;}

#define MIN_GEN_MEM (4 << 20)

	
void  reserve_buffer(const char* cl, ulong base_mem) 
{
	char* pos = strstr(cl, "reserved_buffer=");
 	if (pos) {
		buffer_size = simple_strtol(pos+strlen("reserved_buffer="), 
					    0, 10);
		buffer_size <<= 20;
		if (buffer_size + MIN_GEN_MEM > base_mem)
			buffer_size = base_mem - MIN_GEN_MEM;
		if (buffer_size > 0) 
			buffer_ptr = (ulong*)(base_mem - buffer_size);
		else 
			buffer_size = 0;
	}
}



EXPORT_SYMBOL(get_reserved_buffer);
EXPORT_SYMBOL(get_reserved_buffer_virtual);
EXPORT_SYMBOL(get_reserved_buffer_size);