satip-axe/kernel/drivers/misc/sgi-xp/xp_nofault.S
2015-03-26 17:24:57 +01:00

36 lines
1.3 KiB
ArmAsm

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (c) 2004-2008 Silicon Graphics, Inc. All Rights Reserved.
*/
/*
* The xp_nofault_PIOR function takes a pointer to a remote PIO register
* and attempts to load and consume a value from it. This function
* will be registered as a nofault code block. In the event that the
* PIO read fails, the MCA handler will force the error to look
* corrected and vector to the xp_error_PIOR which will return an error.
*
* The definition of "consumption" and the time it takes for an MCA
* to surface is processor implementation specific. This code
* is sufficient on Itanium through the Montvale processor family.
* It may need to be adjusted for future processor implementations.
*
* extern int xp_nofault_PIOR(void *remote_register);
*/
.global xp_nofault_PIOR
xp_nofault_PIOR:
mov r8=r0 // Stage a success return value
ld8.acq r9=[r32];; // PIO Read the specified register
adds r9=1,r9;; // Add to force consumption
srlz.i;; // Allow time for MCA to surface
br.ret.sptk.many b0;; // Return success
.global xp_error_PIOR
xp_error_PIOR:
mov r8=1 // Return value of 1
br.ret.sptk.many b0;; // Return failure