/*
 * Platform dependent support for IO probing.
 *
 * Copyright (C) 2000   Silicon Graphics
 * Copyright (C) 2000   Jack Steiner (steiner@sgi.com)
 */

#include <asm/sn/sn_sal.h>

/*
 * ia64_sn_probe_io_slot
 *	This function will probe a physical address to determine if
 *	the address can be read. If reading the address causes a BUS
 *	error, an error is returned. If the probe succeeds, the contents 
 *	of the memory location is returned.
 *
 *   Calling sequence:
 *		ia64_probe_io_slot(paddr, size, data_ptr)
 *
 *   Input:
 *	paddr		Physical address to probe
 *	size		Number bytes to read (1,2,4,8)
 *	data_ptr	Address to store value read by probe
 *		          (-1 returned if probe fails)
 *
 *   Output:
 *	Status
 *		 0 - probe successful
 *		 1 - probe failed (generated MCA)
 *		 2 - Bad arg
 *		<0 - PAL error
 */


u64
ia64_sn_probe_io_slot(long paddr, long size, void *data_ptr)
{
	struct ia64_sal_retval isrv;

	SAL_CALL(isrv, SN_SAL_PROBE, paddr, size, 0, 0, 0, 0, 0);

	if (data_ptr) {
		switch (size) {
			case 1:
				*((u8*)data_ptr) = (u8)isrv.v0;
				break;
			case 2:
				*((u16*)data_ptr) = (u16)isrv.v0;
				break;
			case 4:
				*((u32*)data_ptr) = (u32)isrv.v0;
				break;
			case 8:
				*((u64*)data_ptr) = (u64)isrv.v0;
				break;
			default:
				isrv.status = 2;	
		}
	}

	return isrv.status;
}