smihandler.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <arch/io.h>
#include <console/console.h>
#include <cpu/x86/msr.h>
#include <cpu/x86/smm.h>
#include <ec/acpi/ec.h>
#include <soc/nvs.h>
 
/*
 * TODO: Perform RE of protocols in vendor firmware:
 * - gEfiSmmSxDispatch2ProtocolGuid
 * - gEfiSmmPowerButtonDispatch2ProtocolGuid
 *
 * However, note that first glance suggests that no handlers
 * will be very interesting and that gEfiSmmGpiDispatch2ProtocolGuid
 * was unused (as I recall).
 *
 * Also, consider gEfiSmmIoTrapDispatch2ProtocolGuid, but
 * this is less likely.
 */
 
/* Keep in sync with dsdt.asl; could insert into SSDT at runtime */
#define APM_CNT_BOARD_SMI       0xDD
 
/* Toggle TURBO_MODE_DISABLE bit in IA32_MISC_ENABLE MSR
   when requested by EC. */
static void toggle_turbo_disable(uint8_t function_parameter_0)
{
        if (function_parameter_0 == 1) {
                printk(BIOS_DEBUG, "EC: Enabling Intel Turbo Mode\n");
                msr_unset(IA32_MISC_ENABLE, 0x4000000000);
        } else if (function_parameter_0 == 0) {
                printk(BIOS_DEBUG, "EC: Disabling Intel Turbo Mode\n");
                msr_set(IA32_MISC_ENABLE, 0x4000000000);
        }
}
 
/* Set WiFi and BT enable bits in EC RAM. */
static void enable_rf_by_capability(void)
{
        /* FIXME: We're not tracking (driver) 'capabilities' at the moment (must we?),
           so we just enable WiFi and BT here. If this was tracked, then
           bits may be cleared here */
        uint8_t rf_register = ec_read(0x71);
        ec_write(0x71, rf_register | 0x03);
}
 
/* Set OS capability bits in EC RAM. */
static void handle_acpi_osys(void)
{
        uint8_t os_support;
 
        /* TODO: Add _OSI method support to coreboot and make this work */
        printk(BIOS_DEBUG, "GNVS.OSYS = %d\n", gnvs->unused_was_osys);
        switch (gnvs->unused_was_osys) {
        /* Linux */
        case 1000:
                os_support = 64;
                break;
        /* Windows versions by year */
        case 2009:
                os_support = 3;
                break;
        case 2012:
                os_support = 4;
                break;
        case 2013:
                os_support = 5;
                break;
        case 2015:
                os_support = 6;
                break;
        /* Operating system unknown */
        default:
                printk(BIOS_DEBUG, "GNVS.OSYS not supported!\n");
                printk(BIOS_DEBUG, "No capabilities!\n");
                os_support = 0;
                break;
        }
 
        ec_write(0x5C, os_support);
}
 
/* Handles EC's _REG, _PTS and _WAK methods.
   Partially involves setting EC RAM offsets based on GNVS.OSYS - OS capabilities? */
static void handle_acpi_wake_event(
        uint8_t function_parameter_0, uint8_t function_parameter_1)
{
        switch (function_parameter_0) {
        case 1:
                printk(BIOS_DEBUG, "EC: Called for _REG method - OS initialise\n");
                enable_rf_by_capability();
                handle_acpi_osys();
                // NOTE: Not handling (driver) 'capabilities'
                break;
        case 2:
                printk(BIOS_DEBUG, "EC: Called for _PTS method - Entering sleep\n");
                // NOTE: Not saving (driver) 'capabilities'
                // NOTE: Not saving and restoring EC RAM offset 0x4F
                break;
        case 3:
                printk(BIOS_DEBUG, "EC: Called for _WAK method - Sleep resume\n");
                enable_rf_by_capability();
                handle_acpi_osys();
                // NOTE: Not saving and restoring EC RAM offset 0x4F
                break;
        default:
                printk(BIOS_DEBUG, "function_parameter_0 is invalid!\n");
                break;
        }
}
 
/* TODO: Reverse engineer 0x80 function and implement if necessary */
static void ec_smi_handler(uint8_t smif)
{
        uint8_t smm_data_port;
        uint8_t function_parameter_0;
        uint8_t function_parameter_1;
 
        /* Parameters encoded onto SMI data port because PRMx NVS are not present
           - Callers must only use 4 bits per argument
           - _PTS and _WAK are required to call in spec-compliant way */
        smm_data_port = inb(APM_STS);
        function_parameter_0 = smm_data_port & ~0xF0;
        function_parameter_1 = smm_data_port >> 4;
 
        printk(BIOS_DEBUG, "Function 0x%x(0x%x, 0x%x) called\n",
                        smif, function_parameter_0, function_parameter_1);
        switch (smif) {
        case 0x80:
                printk(BIOS_WARNING, "Function 0x80 is unimplemented!\n");
                printk(BIOS_DEBUG, "Function calls offset 0 in ACER_BOOT_DEVICE_SERVICE_PROTOCOL_GUID\n");
                break;
        case 0x81:
                toggle_turbo_disable(function_parameter_0);
                break;
        case 0x82:
                handle_acpi_wake_event(function_parameter_0, function_parameter_1);
                break;
        default:
                /* Not handled */
                printk(BIOS_DEBUG, "Requested function is unknown!\n");
                return;
        }
 
        /*
         * gnvs->smif:
         * - On success, the handler returns 0
         * - On failure, the handler returns a value != 0
         */
        gnvs->smif = 0;
}
 
int mainboard_smi_apmc(u8 data)
{
        /* TODO: Continue SmmKbcDriver RE of common service registration and confirm */
        switch (data) {
        case APM_CNT_BOARD_SMI:
                if (gnvs) {
                        ec_smi_handler(gnvs->smif);
                }
                break;
        case APM_CNT_ACPI_ENABLE:       /* Events generate SCIs for OS */
                /* use 0x68/0x6C to prevent races with userspace */
                ec_set_ports(0x6C, 0x68);
                /* discard all events */
                ec_clear_out_queue();
                /* Tests at runtime show this re-enables charging and battery reporting */
                send_ec_command(0xE9);  /* Vendor implements using ACPI "CMDB" register" */
                send_ec_data(0x81);
                /* TODO: Set touchpad GPP owner to ACPI? */
                break;
        case APM_CNT_ACPI_DISABLE:      /* Events generate SMIs for SMM */
                /* use 0x68/0x6C to prevent races with userspace */
                ec_set_ports(0x6C, 0x68);
                /* discard all events */
                ec_clear_out_queue();
                /* Tests at runtime show this disables charging and battery reporting */
                send_ec_command(0xE9);  /* Vendor implements using ACPI "CMDB" register" */
                send_ec_data(0x80);
                /* TODO: Set touchpad GPP owner to GPIO? */
                break;
        default:
                break;
        }
        return 0;
}