kalloc.c.svn-base

Spearhead2000 的 USB驱动程序

#define NULL 0x0

#define BUF_NUM		9

#define BUF_SZ_16	0	// 64 items (2K)
#define BUF_SZ_32	1	// 64 items (2K)
#define BUF_SZ_64	2	// 64 items (4K)
#define BUF_SZ_128	3	// 32 items (4K)
#define BUF_SZ_256	4	// 16 items (4K)
#define BUF_SZ_512	5	// 8  items (4K)
#define BUF_SZ_1024	6	// 8  items (8K)
#define BUF_SZ_2048	7	// 8  items (16K)
#define BUF_SZ_4096	8	// 8  items (32K)

static struct malloc_freelist
			{
				unsigned int  buf_sz;
				unsigned int  num_items;
				unsigned char *startp;
				unsigned char *bufp;
			} malloc_freelist[BUF_NUM] = 
					{
					16  , 64, 0x0, 0x0,	//BUF_SZ_16
					32  , 64, 0x0, 0x0,	//BUF_SZ_32
					64  , 64, 0x0, 0x0,	//BUF_SZ_64
					128 , 32, 0x0, 0x0,	//BUF_SZ_128
					256 , 16, 0x0, 0x0,	//BUF_SZ_256
					512 , 68 , 0x0, 0x0,	//BUF_SZ_512
					1024, 24 , 0x0, 0x0,	//BUF_SZ_1024
					2048, 8 , 0x0, 0x0,	//BUF_SZ_2048
					4096, 16 , 0x0, 0x0	//BUF_SZ_4096
					};

static unsigned char malloc_buffer[156 * 1024];


void
malloc_init()
{
	unsigned int i, j;
	unsigned int tot_size = 0;
	unsigned char **bpp = (&malloc_freelist[0].bufp);
	
	for (i = 0; i < BUF_NUM; i++)
	{
		bpp = (&malloc_freelist[i].bufp);
		
		for (j = 0; j < malloc_freelist[i].num_items; j++)
		{
			*bpp = &malloc_buffer[tot_size];
			bpp = &malloc_buffer[tot_size];
			tot_size += malloc_freelist[i].buf_sz;
		}
		
		malloc_freelist[i].startp = malloc_freelist[i].bufp;
	}
}

char *
kmalloc(unsigned int size, unsigned int flags)
{
	unsigned int i;
	char *bufp;

	for (i = 0; i < BUF_NUM; i++)
	{
		if (size <= malloc_freelist[i].buf_sz)
			break;
	}
	
	if (malloc_freelist[i].num_items == 0)
		return NULL;	// out of memory

	bufp = 	malloc_freelist[i].bufp;
	malloc_freelist[i].bufp = *((unsigned char **)bufp);
	malloc_freelist[i].num_items--;

	return bufp;	
}

int
kfree(unsigned char *bp)
{
	unsigned int i;

	for (i = 0; i < BUF_NUM - 1; i++)
	{
		if (bp < malloc_freelist[i + 1].startp)
			break;
	}
	
	*((unsigned char **)bp) = malloc_freelist[i].bufp;
	malloc_freelist[i].bufp = bp;
	malloc_freelist[i].num_items++;
	
	return(0);
}