osd-contiki/cpu/x86/drivers/legacy_pc
Andre Guedes cb0510ebcf x86: Disable NMI while initializing RTC
According to [1], we should disable non-maskable and maskable interrupts
while initializing RTC. Otherwise, the RTC may be left in an undefined
state (non-functional) if an interrupt occurs. Currently, maskable
interrupts are already disabled, but NMI is not.

This patch adds helpers APIs to enable/disable non-maskable interrupts
(NMI) and changes rtc_init() to disable NMI while initializing the RTC.

NMI enable/disable code is legacy-PC specific therefore it was put in
driver/legacy_pc/ directory.

Regarding the RTC initialization changes, just calling nmi_disable() and
nmi_enable is not enough since NMI and RTC share the same IO port. So We
should also set the NMI_ENABLE bit while selecting the RTC_INDEX.

Additionally, the nmi_disable() call is not strictly required since we
set the NMI_ENABLE bit while selecting the RTC_INDEX. However, to make
clear hat we are disabling NMI and to improve readability (by matching
NMI disable/enable), the nmi_disable() call was purposely used.

[1] http://wiki.osdev.org/RTC
2015-12-21 08:06:14 -02:00
..
nmi.c x86: Disable NMI while initializing RTC 2015-12-21 08:06:14 -02:00
nmi.h x86: Disable NMI while initializing RTC 2015-12-21 08:06:14 -02:00
pic.c x86: Move available drivers into drivers/legacy_pc/ 2015-12-21 08:06:14 -02:00
pic.h x86: Move available drivers into drivers/legacy_pc/ 2015-12-21 08:06:14 -02:00
pit.c x86: Move available drivers into drivers/legacy_pc/ 2015-12-21 08:06:14 -02:00
pit.h x86: Move available drivers into drivers/legacy_pc/ 2015-12-21 08:06:14 -02:00
rtc.c x86: Disable NMI while initializing RTC 2015-12-21 08:06:14 -02:00
rtc.h x86: Move available drivers into drivers/legacy_pc/ 2015-12-21 08:06:14 -02:00