u-boot/arch/arm/cpu/armv8/fwcall.c

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// SPDX-License-Identifier: GPL-2.0+
/**
* (C) Copyright 2014, Cavium Inc.
* (C) Copyright 2017, Xilinx Inc.
*
**/
#include <asm-offsets.h>
#include <config.h>
#include <version.h>
#include <asm/macro.h>
#include <asm/psci.h>
#include <asm/system.h>
/*
* Issue the hypervisor call
*
* x0~x7: input arguments
* x0~x3: output arguments
*/
static void hvc_call(struct pt_regs *args)
{
asm volatile(
"ldr x0, %0\n"
"ldr x1, %1\n"
"ldr x2, %2\n"
"ldr x3, %3\n"
"ldr x4, %4\n"
"ldr x5, %5\n"
"ldr x6, %6\n"
"hvc #0\n"
"str x0, %0\n"
"str x1, %1\n"
"str x2, %2\n"
"str x3, %3\n"
: "+m" (args->regs[0]), "+m" (args->regs[1]),
"+m" (args->regs[2]), "+m" (args->regs[3])
: "m" (args->regs[4]), "m" (args->regs[5]),
"m" (args->regs[6])
: "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7",
"x8", "x9", "x10", "x11", "x12", "x13", "x14", "x15",
"x16", "x17");
}
/*
* void smc_call(arg0, arg1...arg7)
*
* issue the secure monitor call
*
* x0~x7: input arguments
* x0~x3: output arguments
*/
void smc_call(struct pt_regs *args)
{
asm volatile(
"ldr x0, %0\n"
"ldr x1, %1\n"
"ldr x2, %2\n"
"ldr x3, %3\n"
"ldr x4, %4\n"
"ldr x5, %5\n"
"ldr x6, %6\n"
"smc #0\n"
"str x0, %0\n"
"str x1, %1\n"
"str x2, %2\n"
"str x3, %3\n"
: "+m" (args->regs[0]), "+m" (args->regs[1]),
"+m" (args->regs[2]), "+m" (args->regs[3])
: "m" (args->regs[4]), "m" (args->regs[5]),
"m" (args->regs[6])
: "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7",
"x8", "x9", "x10", "x11", "x12", "x13", "x14", "x15",
"x16", "x17");
}
/*
* For now, all systems we support run at least in EL2 and thus
* trigger PSCI calls to EL3 using SMC. If anyone ever wants to
* use PSCI on U-Boot running below a hypervisor, please detect
* this and set the flag accordingly.
*/
static const bool use_smc_for_psci = true;
void __noreturn psci_system_reset(void)
{
struct pt_regs regs;
regs.regs[0] = ARM_PSCI_0_2_FN_SYSTEM_RESET;
if (use_smc_for_psci)
smc_call(&regs);
else
hvc_call(&regs);
while (1)
;
}
void __noreturn psci_system_off(void)
{
struct pt_regs regs;
regs.regs[0] = ARM_PSCI_0_2_FN_SYSTEM_OFF;
if (use_smc_for_psci)
smc_call(&regs);
else
hvc_call(&regs);
while (1)
;
}