amd/stoneyridge: Refactor SMI handler

Rewrite the handler to be more compact and extendable.  The old
functionality is duplicated after the rewrite.  All SMI source registers
(except for SmiSciStatus) behave identically so these are consolidated.
Register 0x80 contains sources 0-31, 0x81 sources 32-63, and so on.

Create a table of mini-handlers to be supported in the soc directory.
As SMI sources are discovered, attempt to find the corresponding handler
and then execute it.

Change-Id: Ic7050ecf65c2af036fe297f429a0bbdc709ad4c1
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/21746
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marc Jones <marc@marcjonesconsulting.com>

2 files changed, 54 insertions, 46 deletions

diff --git a/src/soc/amd/stoneyridge/include/soc/smi.h b/src/soc/amd/stoneyridge/include/soc/smi.h
index 5e6f6ff31e..0a865b7496 100644
--- a/src/soc/amd/stoneyridge/include/soc/smi.h
+++ b/src/soc/amd/stoneyridge/include/soc/smi.h
@@ -194,6 +194,11 @@ enum smi_lvl {
 	SMI_LVL_HIGH = 1,
 };
 
+struct smi_sources_t {
+	int type;
+	void (*handler)(void);
+};
+
 uint16_t pm_acpi_smi_cmd_port(void);
 void configure_gevent_smi(uint8_t gevent, uint8_t mode, uint8_t level);
 void disable_gevent_smi(uint8_t gevent);
diff --git a/src/soc/amd/stoneyridge/smihandler.c b/src/soc/amd/stoneyridge/smihandler.c
index cabfd3db65..f9bd8d736b 100644
--- a/src/soc/amd/stoneyridge/smihandler.c
+++ b/src/soc/amd/stoneyridge/smihandler.c
@@ -1,8 +1,18 @@
 /*
- * SMI handler for Hudson southbridges
+ * This file is part of the coreboot project.
  *
+ * Copyright (C) 2017 Advanced Micro Devices, Inc.
  * Copyright (C) 2014 Alexandru Gagniuc <mr.nuke.me@gmail.com>
- * Subject to the GNU GPL v2, or (at your option) any later version.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
  */
 
 #include <console/console.h>
@@ -37,6 +47,14 @@ int southbridge_io_trap_handler(int smif)
 	return 0;
 }
 
+/*
+ * Table of functions supported in the SMI handler.  Note that SMI source setup
+ * in southbridge.c is unrelated to this list.
+ */
+struct smi_sources_t smi_sources[] = {
+	{ .type = SMITYPE_SMI_CMD_PORT, .handler = sb_apmc_smi_handler },
+};
+
 static void process_smi_sci(void)
 {
 	const uint32_t status = smi_read32(SMI_SCI_STATUS);
@@ -45,54 +63,39 @@ static void process_smi_sci(void)
 	smi_write32(SMI_SCI_STATUS, status);
 }
 
-static void process_gpe_smi(void)
+static void *get_source_handler(int source)
 {
-	const uint32_t status = smi_read32(SMI_REG_SMISTS0);
+	int i;
 
-	/* Only Bits [23:0] indicate GEVENT SMIs. */
-	if (status & GEVENT_MASK) {
-		/* A GEVENT SMI occurred */
-		mainboard_smi_gpi(status & GEVENT_MASK);
-	}
-
-	/* Clear events to prevent re-entering SMI if event isn't handled */
-	smi_write32(SMI_REG_SMISTS0, status);
-}
-
-static void process_smi_0x84(void)
-{
-	const uint32_t status = smi_read32(SMI_REG_SMISTS1);
+	for (i = 0 ; i < ARRAY_SIZE(smi_sources) ; i++)
+		if (smi_sources[i].type == source)
+			return smi_sources[i].handler;
 
-	/* Clear events to prevent re-entering SMI if event isn't handled */
-	smi_write32(SMI_REG_SMISTS1, status);
+	return NULL;
 }
 
-static void process_smi_0x88(void)
+static void process_smi_sources(uint32_t reg)
 {
-	const uint32_t status = smi_read32(SMI_REG_SMISTS2);
-
-	if (status & TYPE_TO_MASK(SMITYPE_SMI_CMD_PORT)) {
-		/* Command received via ACPI SMI command port */
-		sb_apmc_smi_handler();
+	const uint32_t status = smi_read32(reg);
+	int bit_zero = 32 / sizeof(uint32_t) * (reg - SMI_REG_SMISTS0);
+	void (*source_handler)(void);
+	int i;
+
+	for (i = 0 ; i < 32 ; i++) {
+		if (status & (1 << i)) {
+			source_handler = get_source_handler(i + bit_zero);
+			if (source_handler)
+				source_handler();
+		}
 	}
-	/* Clear events to prevent re-entering SMI if event isn't handled */
-	smi_write32(SMI_REG_SMISTS2, status);
-}
 
-static void process_smi_0x8c(void)
-{
-	const uint32_t status = smi_read32(SMI_REG_SMISTS3);
+	if (reg == SMI_REG_SMISTS0)
+		if (status & GEVENT_MASK)
+			/* Gevent[23:0] are assumed to be mainboard-specific */
+			mainboard_smi_gpi(status & GEVENT_MASK);
 
-	/* Clear events to prevent re-entering SMI if event isn't handled */
-	smi_write32(SMI_REG_SMISTS4, status);
-}
-
-static void process_smi_0x90(void)
-{
-	const uint32_t status = smi_read32(SMI_REG_SMISTS4);
-
-	/* Clear events to prevent re-entering SMI if event isn't handled */
-	smi_write32(SMI_REG_SMISTS4, status);
+	/* Clear all events in this register */
+	smi_write32(reg, status);
 }
 
 void southbridge_smi_handler(void)
@@ -102,15 +105,15 @@ void southbridge_smi_handler(void)
 	if (smi_src & SMI_STATUS_SRC_SCI)
 		process_smi_sci();
 	if (smi_src & SMI_STATUS_SRC_0)
-		process_gpe_smi();
+		process_smi_sources(SMI_REG_SMISTS0);
 	if (smi_src & SMI_STATUS_SRC_1)
-		process_smi_0x84();
+		process_smi_sources(SMI_REG_SMISTS1);
 	if (smi_src & SMI_STATUS_SRC_2)
-		process_smi_0x88();
+		process_smi_sources(SMI_REG_SMISTS2);
 	if (smi_src & SMI_STATUS_SRC_3)
-		process_smi_0x8c();
+		process_smi_sources(SMI_REG_SMISTS3);
 	if (smi_src & SMI_STATUS_SRC_4)
-		process_smi_0x90();
+		process_smi_sources(SMI_REG_SMISTS4);
 }
 
 void southbridge_smi_set_eos(void)