t480/3050micro: force power off post power failure

The T480 has no option table, because it lacks nvram, so the
default option applies, which seems to be power on after power
failure. This is undesirable on a laptop.

It's triggered simply when your laptop battery runs out, and
once triggered, it couldn't be configured at all.

Hard-code this. The documentation will be updated later on
after this patch is pushed, telling those users who want
to change this behaviour how to modify/remove the patch,
if they wish to to do so, because some people may actually
want to run a server on the OptiPlex 3050 Micro (or if they're
crazy like I am, they will host libreboot.org on a ThinkPad).

Signed-off-by: Leah Rowe <leah@libreboot.org>

1 files changed, 82 insertions, 0 deletions

diff --git a/config/coreboot/next/patches/0013-soc-intel-pmc-Hardcoded-poweroff-after-power-fail.patch b/config/coreboot/next/patches/0013-soc-intel-pmc-Hardcoded-poweroff-after-power-fail.patch
new file mode 100644
index 00000000..6ea65c8d
--- /dev/null
+++ b/config/coreboot/next/patches/0013-soc-intel-pmc-Hardcoded-poweroff-after-power-fail.patch
@@ -0,0 +1,82 @@
+From aa13bb380d8286373089de291b62c6070df20573 Mon Sep 17 00:00:00 2001
+From: Leah Rowe <info@minifree.org>
+Date: Tue, 31 Dec 2024 01:40:42 +0000
+Subject: [PATCH 1/1] soc/intel/pmc: Hardcoded poweroff after power fail
+
+Coreboot can set the power state for power on after previous
+power failure, based on the option table. On the ThinkPad T480,
+we have no nvram and, due to coreboot's design, we therefore
+have no option table, so the default setting is enabled.
+
+In my testing, this seems to be that the system will turn on
+after a power failure. If your ThinkPad was previously in a state
+where it wouldn't turn on when plugging in the power, it'd be fine.
+
+If your battery ran out later on, this would be triggered and
+your ThinkPad would permanently turn on, when plugging in a charger,
+and there is currently no way to configure this behaviour.
+
+We currently only use the common SoC PMC code on the ThinkPad
+T480, T480s and the Dell OptiPlex 3050 Micro, at the time of
+this patch, and it is desirable that the system be set to power
+off after power fail anyway.
+
+In some cases, you might want the opposite, for example if you're
+running a server. This will be documented on the website, for that
+reason.
+
+Signed-off-by: Leah Rowe <info@minifree.org>
+---
+ src/soc/intel/common/block/pmc/pmclib.c | 36 +++----------------------
+ 1 file changed, 4 insertions(+), 32 deletions(-)
+
+diff --git a/src/soc/intel/common/block/pmc/pmclib.c b/src/soc/intel/common/block/pmc/pmclib.c
+index c51a960854..a836932fe5 100644
+--- a/src/soc/intel/common/block/pmc/pmclib.c
++++ b/src/soc/intel/common/block/pmc/pmclib.c
+@@ -760,38 +760,10 @@ void pmc_clear_pmcon_sts(void)
+ 
+ void pmc_set_power_failure_state(const bool target_on)
+ {
+-	const unsigned int state = get_uint_option("power_on_after_fail",
+-					 CONFIG_MAINBOARD_POWER_FAILURE_STATE);
+-
+-	/*
+-	 * On the shutdown path (target_on == false), we only need to
+-	 * update the register for MAINBOARD_POWER_STATE_PREVIOUS. For
+-	 * all other cases, we don't write the register to avoid clob-
+-	 * bering the value set on the boot path. This is necessary,
+-	 * for instance, when we can't access the option backend in SMM.
+-	 */
+-
+-	switch (state) {
+-	case MAINBOARD_POWER_STATE_OFF:
+-		if (!target_on)
+-			break;
+-		printk(BIOS_INFO, "Set power off after power failure.\n");
+-		pmc_soc_set_afterg3_en(false);
+-		break;
+-	case MAINBOARD_POWER_STATE_ON:
+-		if (!target_on)
+-			break;
+-		printk(BIOS_INFO, "Set power on after power failure.\n");
+-		pmc_soc_set_afterg3_en(true);
+-		break;
+-	case MAINBOARD_POWER_STATE_PREVIOUS:
+-		printk(BIOS_INFO, "Keep power state after power failure.\n");
+-		pmc_soc_set_afterg3_en(target_on);
+-		break;
+-	default:
+-		printk(BIOS_WARNING, "Unknown power-failure state: %d\n", state);
+-		break;
+-	}
++	if (!target_on)
++		return;
++	printk(BIOS_INFO, "Set power off after power failure.\n");
++	pmc_soc_set_afterg3_en(false);
+ }
+ 
+ /* This function returns the highest assertion duration of the SLP_Sx assertion widths */
+-- 
+2.39.5
+