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Tegra: Enable irq as wake-up event for cpu_standby 

As per ARM ARM D1.17.2, any physical IRQ interrupt received by the PE
will be treated as a wake-up event, if SCR_EL3.IRQ is set to '1',
irrespective of the value of the PSTATE.I bit value.

This patch programs the SCR_EL3.IRQ bit before entering CPU standby
state, to allow an IRQ to wake the PE. On waking up, the previous
SCR_EL3 value is restored.

Change-Id: Ie81cf3a7668f5ac35f4bf2ecc461b91b9b60650c
Signed-off-by: Vignesh Radhakrishnan <vigneshr@nvidia.com>
This commit is contained in:
Vignesh Radhakrishnan 2018-04-20 14:31:41 -07:00 committed by Varun Wadekar
parent b695af1dfc
commit 07faf4d8c5
1 changed files with 21 additions and 2 deletions
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23
plat/nvidia/tegra/common/tegra_pm.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
* Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@ -146,18 +146,37 @@ void tegra_get_sys_suspend_power_state(psci_power_state_t *req_state)
******************************************************************************/
void tegra_cpu_standby(plat_local_state_t cpu_state)
{
u_register_t saved_scr_el3;
(void)cpu_state;
/* Tegra SoC specific handler */
if (tegra_soc_cpu_standby(cpu_state) != PSCI_E_SUCCESS)
ERROR("%s failed\n", __func__);
saved_scr_el3 = read_scr_el3();
/*
* As per ARM ARM D1.17.2, any physical IRQ interrupt received by the
* PE will be treated as a wake-up event, if SCR_EL3.IRQ is set to '1',
* irrespective of the value of the PSTATE.I bit value.
*/
write_scr_el3(saved_scr_el3 | SCR_IRQ_BIT);
/*
* Enter standby state
* dsb is good practice before using wfi to enter low power states
*
* dsb & isb is good practice before using wfi to enter low power states
*/
dsb();
isb();
wfi();
/*
* Restore saved scr_el3 that has IRQ bit cleared as we don't want EL3
* handling any further interrupts
*/
write_scr_el3(saved_scr_el3);
}
/*******************************************************************************