Change in coreboot[master]: soc/intel/skylake: Make usage of SMI optional where possible

[dhaval v sharma (Code Review)]

dhaval v sharma has uploaded this change for review. ( https://review.coreboot.org/28696

Change subject: soc/intel/skylake: Make usage of SMI optional where possible
......................................................................

soc/intel/skylake: Make usage of SMI optional where possible

Make usage of SMI optional where possible 3 different
hooks provided as such:
1. Most modern OSes are ACPI aware-avoid ACPI switch SMI if
   possible.
2. Avoid finalize soc SMI. Most finalize implementation
   can be done in normal code.
3. Do not need to disable ACPI during boot - leave it
   enabled through boot.

Note: With reduced SMI PWRBTN event based graceful shutdown
will not work until OS is booted.

BUG=None
BRANCH=None
TEST=Booted Soraka with option enabled/disabled.

Change-Id: I3f0c64b15ed6d0854ff350fcd75d299e45c23f18
Signed-off-by: Dhaval 
---
M src/ec/google/chromeec/ec.c
M src/soc/intel/common/block/smm/Kconfig
M src/soc/intel/skylake/acpi.c
M src/soc/intel/skylake/finalize.c
M src/soc/intel/skylake/pmc.c
5 files changed, 26 insertions(+), 8 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/96/28696/1

diff --git a/src/ec/google/chromeec/ec.c b/src/ec/google/chromeec/ec.c
index 09550d5..f2f4e0d 100644
--- a/src/ec/google/chromeec/ec.c
+++ b/src/ec/google/chromeec/ec.c
@@ -474,9 +474,6 @@
    	while (google_chromeec_get_event() != 0)
    		;

-		/* Restore SCI event mask. */
-		google_chromeec_set_sci_mask(info->sci_events);
-
    } else {
    	google_chromeec_set_smi_mask(info->smi_events);

@@ -489,6 +486,13 @@
    				info->s3_wake_events,
    				info->s0ix_wake_events);
    }
+	/* Should be okay to set sci mask for s0 path also because
+	 * anyways SCI interrupt gets enabled later during finalize
+	 * stage and ACPI_DISABLE calls can explicitely disable it
+	 * as required this helps with SMI_REDUCED implementation*/
+
+	google_chromeec_set_sci_mask(info->sci_events);
+

/* Clear wake event mask. */
    google_chromeec_set_wake_mask(0);
diff --git a/src/soc/intel/common/block/smm/Kconfig b/src/soc/intel/common/block/smm/Kconfig
index 909382e..064d4d8 100644
--- a/src/soc/intel/common/block/smm/Kconfig
+++ b/src/soc/intel/common/block/smm/Kconfig
@@ -16,3 +16,9 @@
      Time in milliseconds that SLP_SMI for S5 waits for before
      enabling sleep. This is required to avoid any race between
      SLP_SMI and PWRBTN SMI.
+
+config REDUCED_SMI
+	bool "Reduce SMI usage during boot"
+	default n
+	help
+	  Reduce SMI usage
diff --git a/src/soc/intel/skylake/acpi.c b/src/soc/intel/skylake/acpi.c
index d2ec7e7..5f018ef 100644
--- a/src/soc/intel/skylake/acpi.c
+++ b/src/soc/intel/skylake/acpi.c
@@ -244,7 +244,13 @@
    fadt->header.revision = get_acpi_table_revision(FADT);

fadt->sci_int = acpi_sci_irq();
-	fadt->smi_cmd = APM_CNT;
+
+	if (IS_ENABLED(CONFIG_REDUCED_SMI))
+	/* ACPI 2.0: if SMI_CMD in FADT is zero no SMI transitions supported */
+		fadt->smi_cmd = 0;
+	else
+		fadt->smi_cmd = APM_CNT;
+
    fadt->acpi_enable = APM_CNT_ACPI_ENABLE;
    fadt->acpi_disable = APM_CNT_ACPI_DISABLE;
    fadt->s4bios_req = 0x0;
diff --git a/src/soc/intel/skylake/finalize.c b/src/soc/intel/skylake/finalize.c
index 4c8a129..996088d 100644
--- a/src/soc/intel/skylake/finalize.c
+++ b/src/soc/intel/skylake/finalize.c
@@ -144,9 +144,10 @@

soc_lockdown(dev);

-	printk(BIOS_DEBUG, "Finalizing SMM.\n");
-	outb(APM_CNT_FINALIZE, APM_CNT);
-
+	if (!IS_ENABLED(CONFIG_REDUCED_SMI)){
+		printk(BIOS_DEBUG, "Finalizing SMM.\n");
+		outb(APM_CNT_FINALIZE, APM_CNT);
+	}
    /* Indicate finalize step with post code */
    post_code(POST_OS_BOOT);
 }
diff --git a/src/soc/intel/skylake/pmc.c b/src/soc/intel/skylake/pmc.c
index a2623d9..4f77414 100644
--- a/src/soc/intel/skylake/pmc.c
+++ b/src/soc/intel/skylake/pmc.c
@@ -190,7 +190,8 @@
    /* Note that certain bits may be cleared from running script as
     * certain bit fields are write 1 to clear. */
    reg_script_run_on_dev(dev, pch_pmc_misc_init_script);
-	pmc_set_acpi_mode();
+	if (!IS_ENABLED(CONFIG_REDUCED_SMI))
+		pmc_set_acpi_mode();

config_deep_s3(config->deep_s3_enable_ac, config->deep_s3_enable_dc);
    config_deep_s5(config->deep_s5_enable_ac, config->deep_s5_enable_dc);