soc/intel/common: Add InSMM.STS support

Tested on HP 280 G2, SMMSTORE v1 and v2 still work.

Other tests:
- If one does not set BIOS_CONTROL bit WPD, SMMSTORE breaks.
- If one does not write the magic MSR `or 1`, SMMSTORE breaks.

Change-Id: Ia90c0e3f8ccf895bfb6d46ffe26750393dab95fb
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51796
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/include/cpu/intel/msr.h

@@ -26,6 +26,8 @@
 #define  AESNI_DISABLE		(1 << 1)
 #define  AESNI_LOCK		(1 << 0)
 
+#define MSR_SPCL_CHIPSET_USAGE	0x1fe
+
 #define MSR_PKG_C10_RESIDENCY	0x632
 
 #endif /* CPU_INTEL_MSR_H */

src/soc/intel/common/block/smm/smihandler.c

@@ -2,12 +2,15 @@
 
 #include <arch/hlt.h>
 #include <arch/io.h>
+#include <arch/mmio.h>
 #include <device/pci_ops.h>
 #include <console/console.h>
 #include <cpu/x86/cache.h>
+#include <cpu/x86/msr.h>
 #include <cpu/x86/smm.h>
 #include <cpu/intel/em64t100_save_state.h>
 #include <cpu/intel/em64t101_save_state.h>
+#include <cpu/intel/msr.h>
 #include <delay.h>
 #include <device/pci_def.h>
 #include <elog.h>
@@ -260,6 +263,20 @@ static void southbridge_smi_gsmi(
 	save_state_ops->set_reg(io_smi, RAX, ret);
 }
 
+static void set_insmm_sts(const bool enable_writes)
+{
+	msr_t msr = {
+		.lo = read32p(0xfed30880),
+		.hi = 0,
+	};
+	if (enable_writes)
+		msr.lo |= 1;
+	else
+		msr.lo &= ~1;
+
+	wrmsr(MSR_SPCL_CHIPSET_USAGE, msr);
+}
+
 static void southbridge_smi_store(
 	const struct smm_save_state_ops *save_state_ops)
 {
@@ -278,6 +295,7 @@ static void southbridge_smi_store(
 
 	const bool wp_enabled = !fast_spi_wpd_status();
 	if (wp_enabled) {
+		set_insmm_sts(true);
 		fast_spi_disable_wp();
 		/* Not clearing SPI sync SMI status here results in hangs */
 		fast_spi_clear_sync_smi_status();
@@ -287,8 +305,10 @@ static void southbridge_smi_store(
 	ret = smmstore_exec(sub_command, (void *)(uintptr_t)reg_ebx);
 	save_state_ops->set_reg(io_smi, RAX, ret);
 
-	if (wp_enabled)
+	if (wp_enabled) {
 		fast_spi_enable_wp();
+		set_insmm_sts(false);
+	}
 }
 
 static void finalize(void)
@@ -305,8 +325,10 @@ static void finalize(void)
 		/* Re-init SPI driver to handle locked BAR */
 		fast_spi_init();
 
-	if (CONFIG(BOOTMEDIA_SMM_BWP))
+	if (CONFIG(BOOTMEDIA_SMM_BWP)) {
 		fast_spi_enable_wp();
+		set_insmm_sts(false);
+	}
 
 	/*
 	 * HECI is disabled in smihandler_soc_at_finalize() which also locks down the side band
@@ -403,6 +425,7 @@ void smihandler_southbridge_tco(
 		 */
 		printk(BIOS_DEBUG, "Switching SPI back to RO\n");
 		fast_spi_enable_wp();
+		set_insmm_sts(false);
 	}
 
 	/* Any TCO event? */

src/soc/intel/common/pch/lockdown/lockdown.c

@@ -67,7 +67,7 @@ static void fast_spi_lockdown_cfg(int chipset_lockdown)
 
 		/* Only allow writes in SMM */
 		if (CONFIG(BOOTMEDIA_SMM_BWP)) {
-			//fast_spi_set_eiss();	/* TODO */
+			fast_spi_set_eiss();
 			fast_spi_enable_wp();
 		}