hp/pavilion_m6_1035dx: Add SMI handler and handle EC requests

The EC may disable some functionality, such as Caps Lock LED and
battery charging if it never receives a command to go in APM mode. If
we start it in APM mode, then immediately switch to ACPI mode, it will
not get its SCIs serviced until an ACPI OS boots. If its SCIs are not
serviced, it may assume the OS has hung.

The way we solve this is to initalize the EC in APM mode, and only
switch it to ACPI when an ACPI-capable OS issues the ACPI_ENABLE
command. The switch has to be handled in SMM.

Although we aren't yet processing SMIs from the EC, we are reading the
status in order to satisfy the EC that the event is handled.

Change-Id: Iffaeb9a6f57841f456c4bce8337dc09b287f8758
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/5512
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@gmail.com>

src/mainboard/hp/pavilion_m6_1035dx/Kconfig

@@ -30,6 +30,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select HAVE_PIRQ_TABLE
 	select HAVE_MP_TABLE
 	select HAVE_ACPI_RESUME
+	select HAVE_SMI_HANDLER
 	select SERIAL_CPU_INIT
 	select HAVE_ACPI_TABLES
 	select BOARD_ROMSIZE_KB_4096

src/mainboard/hp/pavilion_m6_1035dx/Makefile.inc

@@ -27,3 +27,5 @@ ramstage-y += agesawrapper.c
 ramstage-y += BiosCallOuts.c
 ramstage-y += PlatformGnbPcie.c
 ramstage-y += ec.c
+
+smm-y += mainboard_smi.c

src/mainboard/hp/pavilion_m6_1035dx/ec.c

@@ -13,16 +13,24 @@ static void set_keyboard_matrix_us(void)
 	ec_kbc_write_ib(0xE5);
 }
 
-/* Tell EC to operate in ACPI mode, thus generating SCIs on events, not SMIs */
-static void enter_acpi_mode(void)
+/* Tell EC to operate in APM mode. Events generate SMIs instead of SCIs */
+static void enter_apm_mode(void)
 {
 	ec_kbc_write_cmd(0x59);
-	ec_kbc_write_ib(0xE8);
+	ec_kbc_write_ib(0xE9);
 }
 
 void pavilion_m6_1035dx_ec_init(void)
 {
 	set_keyboard_matrix_us();
-	/* This could also be done in an SMI, should we decide to use SMM */
-	enter_acpi_mode();
+
+	/*
+	 * The EC has a special "blinking Caps Lock LED" mode which it normally
+	 * enters when it believes the OS is not responding. It occasionally
+	 * disables battery charging when in this mode, although other
+	 * functionality is unaffected. Although the EC starts in APM mode by
+	 * default, it only leaves the "blinking Caps Lock LED" mode after
+	 * receiving the following command.
+	 */
+	enter_apm_mode();
 }

src/mainboard/hp/pavilion_m6_1035dx/ec.h

@@ -6,6 +6,10 @@
 #ifndef _MAINBOARD_HP_PAVILION_M6_1035DX_EC_H
 #define _MAINBOARD_HP_PAVILION_M6_1035DX_EC_H
 
+#define EC_SMI_GEVENT		23
+
+#ifndef __SMM__
 void pavilion_m6_1035dx_ec_init(void);
+#endif
 
 #endif /* _MAINBOARD_HP_PAVILION_M6_1035DX_EC_H   */

src/mainboard/hp/pavilion_m6_1035dx/mainboard.c

@@ -30,6 +30,8 @@
 #include <device/pci.h>
 #include <device/pci_def.h>
 
+#include <southbridge/amd/agesa/hudson/smi.h>
+
 /*************************************************
  * enable the dedicated function in parmer board.
  *************************************************/
@@ -39,6 +41,9 @@ static void mainboard_enable(device_t dev)
 
 	pavilion_m6_1035dx_ec_init();
 
+	hudson_enable_gevent_smi(EC_SMI_GEVENT);
+	hudson_enable_smi_generation();
+
 	/*
 	 * The mainboard is the first place that we get control in ramstage. Check
 	 * for S3 resume and call the approriate AGESA/CIMx resume functions.

src/mainboard/hp/pavilion_m6_1035dx/mainboard_smi.c

@@ -0,0 +1,77 @@
+/*
+ * SMI handler -- mostly takes care of SMIs from the EC
+ *
+ * Copyright (C) 2014 Alexandru Gagniuc <mr.nuke.me@gmail.com>
+ * Subject to the GNU GPL v2, or (at your option) any later version.
+ */
+#include "ec.h"
+
+#include <console/console.h>
+#include <cpu/x86/smm.h>
+#include <delay.h>
+#include <ec/compal/ene932/ec.h>
+#include <southbridge/amd/agesa/hudson/hudson.h>
+
+enum ec_smi_event {
+	EC_SMI_EVENT_IDLE = 0x80,
+};
+
+/* Tell EC to operate in APM mode. Events generate SMIs instead of SCIs */
+static void ec_enter_apm_mode(void)
+{
+	ec_kbc_write_cmd(0x59);
+	ec_kbc_write_ib(0xE9);
+}
+/* Tell EC to operate in ACPI mode, thus generating SCIs on events, not SMIs */
+static void ec_enter_acpi_mode(void)
+{
+	ec_kbc_write_cmd(0x59);
+	ec_kbc_write_ib(0xE8);
+}
+
+static uint8_t ec_get_smi_event(void)
+{
+	ec_kbc_write_cmd(0x56);
+	return ec_kbc_read_ob();
+}
+
+static void ec_process_smi(uint8_t src)
+{
+	/*
+	 * Stub: We aren't processing any events yet, but reading the SMI source
+	 * satisfies the EC in terms of responding to the event.
+	 */
+
+	printk(BIOS_DEBUG, "EC_SMI event 0x%x\n", src);
+}
+
+static void handle_ec_smi(void)
+{
+	uint8_t src;
+
+	while ((src = ec_get_smi_event()) != EC_SMI_EVENT_IDLE)
+		ec_process_smi(src);
+}
+
+int mainboard_smi_apmc(uint8_t data)
+{
+	switch (data) {
+	case ACPI_SMI_CMD_ENABLE:
+		printk(BIOS_DEBUG, "Enable ACPI mode\n");
+		ec_enter_acpi_mode();
+		break;
+	case ACPI_SMI_CMD_DISABLE:
+		printk(BIOS_DEBUG, "Disable ACPI mode\n");
+		ec_enter_apm_mode();
+		break;
+	default:
+		printk(BIOS_DEBUG, "Unhandled ACPI command: 0x%x\n", data);
+	}
+	return 0;
+}
+
+void mainboard_smi_gpi(uint32_t gpi_sts)
+{
+	if (gpi_sts & (1 << EC_SMI_GEVENT))
+		handle_ec_smi();
+}