mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-21 03:33:59 +08:00
94c4c79f2f
Make sure the RTT-interrupts are masked at boot by adding a new helper function to be used at SOC-init. This fixes hanged boot on all AT91 SOCs with an RTT, for example, if an RTT-alarm goes off after a non-clean shutdown (e.g. when using RTC wakeup). The RTC and RTT-peripherals are powered by backup power (VDDBU) (on all AT91 SOCs but RM9200) and are not reset on wake-up, user, watchdog or software reset. This means that their interrupts may be enabled during early boot if, for example, they where not disabled during a previous shutdown (e.g. due to a buggy driver or a non-clean shutdown such as a user reset). Furthermore, an RTC or RTT-alarm may also be active. The RTC and RTT-interrupts use the shared system-interrupt line, which is also used by the PIT, and if an interrupt occurs before a handler (e.g. RTC-driver) has been installed this leads to the system interrupt being disabled and prevents the system from booting. Note that when boot hangs due to an early RTC or RTT-interrupt, the only way to get the system to start again is to remove the backup power (e.g. battery) or to disable the interrupt manually from the bootloader. In particular, a user reset is not sufficient. Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com> Cc: stable@vger.kernel.org # 3.11.x
72 lines
1.9 KiB
C
72 lines
1.9 KiB
C
/*
|
|
* sysirq_mask.c - System-interrupt masking
|
|
*
|
|
* Copyright (C) 2013 Johan Hovold <jhovold@gmail.com>
|
|
*
|
|
* Functions to disable system interrupts from backup-powered peripherals.
|
|
*
|
|
* The RTC and RTT-peripherals are generally powered by backup power (VDDBU)
|
|
* and are not reset on wake-up, user, watchdog or software reset. This means
|
|
* that their interrupts may be enabled during early boot (e.g. after a user
|
|
* reset).
|
|
*
|
|
* As the RTC and RTT share the system-interrupt line with the PIT, an
|
|
* interrupt occurring before a handler has been installed would lead to the
|
|
* system interrupt being disabled and prevent the system from booting.
|
|
*
|
|
* 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
|
|
* (at your option) any later version.
|
|
*/
|
|
|
|
#include <linux/io.h>
|
|
#include <mach/at91_rtt.h>
|
|
|
|
#include "generic.h"
|
|
|
|
#define AT91_RTC_IDR 0x24 /* Interrupt Disable Register */
|
|
#define AT91_RTC_IMR 0x28 /* Interrupt Mask Register */
|
|
|
|
void __init at91_sysirq_mask_rtc(u32 rtc_base)
|
|
{
|
|
void __iomem *base;
|
|
u32 mask;
|
|
|
|
base = ioremap(rtc_base, 64);
|
|
if (!base)
|
|
return;
|
|
|
|
mask = readl_relaxed(base + AT91_RTC_IMR);
|
|
if (mask) {
|
|
pr_info("AT91: Disabling rtc irq\n");
|
|
writel_relaxed(mask, base + AT91_RTC_IDR);
|
|
(void)readl_relaxed(base + AT91_RTC_IMR); /* flush */
|
|
}
|
|
|
|
iounmap(base);
|
|
}
|
|
|
|
void __init at91_sysirq_mask_rtt(u32 rtt_base)
|
|
{
|
|
void __iomem *base;
|
|
void __iomem *reg;
|
|
u32 mode;
|
|
|
|
base = ioremap(rtt_base, 16);
|
|
if (!base)
|
|
return;
|
|
|
|
reg = base + AT91_RTT_MR;
|
|
|
|
mode = readl_relaxed(reg);
|
|
if (mode & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN)) {
|
|
pr_info("AT91: Disabling rtt irq\n");
|
|
mode &= ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
|
|
writel_relaxed(mode, reg);
|
|
(void)readl_relaxed(reg); /* flush */
|
|
}
|
|
|
|
iounmap(base);
|
|
}
|