drivers/gpu/arm/midgard/mali_kbase_smc.c

/*
 *
 * (C) COPYRIGHT 2015, 2018 ARM Limited. All rights reserved.
 *
 * This program is free software and is provided to you under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation, and any use by you of this program is subject to the terms
 * of such GNU licence.
 *
 * 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, you can access it online at
 * http://www.gnu.org/licenses/gpl-2.0.html.
 *
 * SPDX-License-Identifier: GPL-2.0
 *
 */

#ifdef CONFIG_ARM64

#include <mali_kbase.h>
#include <mali_kbase_smc.h>

#include <linux/compiler.h>

/* __asmeq is not available on Kernel versions >= 4.20 */
#ifndef __asmeq
/*
 * This is used to ensure the compiler did actually allocate the register we
 * asked it for some inline assembly sequences.  Apparently we can't trust the
 * compiler from one version to another so a bit of paranoia won't hurt.  This
 * string is meant to be concatenated with the inline asm string and will
 * cause compilation to stop on mismatch.  (for details, see gcc PR 15089)
 */
#define __asmeq(x, y)  ".ifnc " x "," y " ; .err ; .endif\n\t"
#endif

static noinline u64 invoke_smc_fid(u64 function_id,
		u64 arg0, u64 arg1, u64 arg2)
{
	register u64 x0 asm("x0") = function_id;
	register u64 x1 asm("x1") = arg0;
	register u64 x2 asm("x2") = arg1;
	register u64 x3 asm("x3") = arg2;

	asm volatile(
			__asmeq("%0", "x0")
			__asmeq("%1", "x1")
			__asmeq("%2", "x2")
			__asmeq("%3", "x3")
			"smc    #0\n"
			: "+r" (x0)
			: "r" (x1), "r" (x2), "r" (x3));

	return x0;
}

u64 kbase_invoke_smc_fid(u32 fid, u64 arg0, u64 arg1, u64 arg2)
{
	/* Is fast call (bit 31 set) */
	KBASE_DEBUG_ASSERT(fid & ~SMC_FAST_CALL);
	/* bits 16-23 must be zero for fast calls */
	KBASE_DEBUG_ASSERT((fid & (0xFF << 16)) == 0);

	return invoke_smc_fid(fid, arg0, arg1, arg2);
}

u64 kbase_invoke_smc(u32 oen, u16 function_number, bool smc64,
		u64 arg0, u64 arg1, u64 arg2)
{
	u32 fid = 0;

	/* Only the six bits allowed should be used. */
	KBASE_DEBUG_ASSERT((oen & ~SMC_OEN_MASK) == 0);

	fid |= SMC_FAST_CALL; /* Bit 31: Fast call */
	if (smc64)
		fid |= SMC_64; /* Bit 30: 1=SMC64, 0=SMC32 */
	fid |= oen; /* Bit 29:24: OEN */
	/* Bit 23:16: Must be zero for fast calls */
	fid |= (function_number); /* Bit 15:0: function number */

	return kbase_invoke_smc_fid(fid, arg0, arg1, arg2);
}

#endif /* CONFIG_ARM64 */