codezero/tasks/blkdev0/src/ramdisk.c

/*
 * A basic ramdisk implementation.
 *
 * Copyright (C) 2007 Bahadir Balban
 *
 * The ramdisk binary is embedded in the data section of the ramdisk device
 * executable. Read/writes simply occur to this area. The disk area could
 * have any filesystem layout e.g. romfs, which is irrelevant for this code.
 */
#include <blkdev.h>
#include <ramdisk.h>
#include <l4/macros.h>
#include <l4/config.h>
#include <l4/types.h>
#include <string.h>
#include INC_SUBARCH(mm.h)
#include INC_GLUE(memory.h)

/* Ramdisk section markers for ramdisk inside this executable image */
extern char _start_ramdisk0[];
extern char _end_ramdisk0[];
extern char _start_ramdisk1[];
extern char _end_ramdisk1[];

__attribute__((section(".data.sfs"))) char sfsdisk[SZ_16MB];

static unsigned long ramdisk_base[2];

void ramdisk_open(struct block_device *ramdisk)
{
	ramdisk_base = (unsigned long)_start_ramdisk;
	ramdisk->size = (unsigned long)_end_ramdisk -
			(unsigned long)_start_ramdisk;
}

void ramdisk_read(unsigned long offset, int size, void *buf)
{
	void *src = (void *)(ramdisk_base + offset);

	memcpy(buf, src, size);
}

void ramdisk_write(unsigned long offset, int size, void *buf)
{
	void *dst = (void *)(ramdisk_base + offset);

	memcpy(dst, buf, size);
}

void ramdisk_readpage(unsigned long pfn, void *buf)
{
	ramdisk_read(__pfn_to_addr(pfn), PAGE_SIZE, buf);
}

void ramdisk_writepage(unsigned long pfn, void *buf)
{
	ramdisk_write(__pfn_to_addr(pfn), PAGE_SIZE, buf);
}

struct block_device ramdisk[2] = {
	[0] = {
		.name = "ramdisk0",
		.ops = {
			.open = ramdisk_open,
			.read = ramdisk_read,
			.write = ramdisk_write,
			.read_page = ramdisk_readpage,
			.write_page = ramdisk_writepage,
		},
	},
	[1] = {
		.name = "ramdisk1",
		.ops = {
			.open = ramdisk_open,
			.read = ramdisk_read,
			.write = ramdisk_write,
			.read_page = ramdisk_readpage,
			.write_page = ramdisk_writepage,
		},
	}
};