Have similar implementation on braswell, so as long as sc_init get executed in ramstage the serial irq mode programming shall be working.

Zhiwen Zheng <> 于2021年11月6日周六 下午6:29写道:
I add the following code to sc_init() in southcluster.c to enable SERIRQ, and it works as expected when doing cold boot. With SERIRQ enabled, the uart in superio can function correctly, and I can login into the linux serial console. But after a reboot initiated from linux cmdline, the linux boot hang in getty serial(same as without SERIRQ enabled), only a power cycle can resolve the issue. I take the following code from coreboot-4.11 fsp-baytrail. I also tried the check_for_warm_reset() in bootblock.c to hardreset the machine, but the check condition in that procedure doesn't catch this situation, linux reset by default use keyboard controller seemingly.

u32 *oic = (u32 *)(ILB_BASE_ADDRESS + 0x60);
u8 *serirq_cntl = (u8 *)(ILB_BASE_ADDRESS + 0x10);

/* Enable SERIRQ */
 write32(oic, (read32(oic) | (1 << 12)));
/* Enable continuous mode */
write8(serirq_cntl, (1 << 7));
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