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/*
* Copyright (C) 2025 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/** @file
*
* T-Head vendor extensions
*
*/
#include <ipxe/sbi.h>
#include <ipxe/xthead.h>
/** Colour for debug messages */
#define colour THEAD_MVENDORID
/**
* Check for a T-Head feature via SXSTATUS register
*
* @v feature Feature bit
* @ret supported Feature is supported
*/
int xthead_supported ( unsigned long feature ) {
struct sbi_return ret;
unsigned long sxstatus;
/* Check for a T-Head CPU */
ret = sbi_ecall_0 ( SBI_BASE, SBI_BASE_MVENDORID );
if ( ret.error )
return 0;
if ( ret.value != THEAD_MVENDORID ) {
DBGC ( colour, "THEAD vendor ID mismatch: %#08lx\n",
ret.value );
return 0;
}
/* Read SXSTATUS CSR */
__asm__ ( "csrr %0, %1"
: "=r" ( sxstatus ) : "i" ( THEAD_SXSTATUS ) );
DBGC ( colour, "THEAD sxstatus %#08lx\n", sxstatus );
/* Check feature bit */
return ( !! ( sxstatus & feature ) );
}
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