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
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legacy_pc	x86: Disable NMI while initializing RTC	2015-12-21 08:06:14 -02:00