ec.c

Go to the documentation of this file.

/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <arch/io.h>
#include <ec/acpi/ec.h>
#include "include/ec.h"
 
/*
 * Notes:
 * - ACPI "CMDB": Writing to this offset is equivalent to sending commands.
 *   The CMDx bytes contain the command parameters.
 *
 * TODO - Implement:
 *   - Commands: 0x58, 0xE1 and 0xE2
 *     - 0x51, 0x52: EC flash write?
 *   - ACPI CMDB: 0x63 and 0x64, 0xC7
 *     - 0x0B: Flash lock/write (Set offset 0x0B?)
 *   - Key/recovery detection?
 *
 * Vendor's protocols:
 * - Only read and write are used.
 * - Query, ACPI "CMDB" processing and command 58 are unused.
 * - Equivalent KbcPeim is an unused PPI.
 *
 * NB: Also look for potential EC library
 */
 
#define EC_INDEX_IO_PORT                0x1200
#define EC_INDEX_IO_HIGH_ADDR_PORT      (EC_INDEX_IO_PORT + 1)
#define EC_INDEX_IO_LOW_ADDR_PORT       (EC_INDEX_IO_PORT + 2)
#define EC_INDEX_IO_DATA_PORT           (EC_INDEX_IO_PORT + 3)
 
uint8_t ec_cmd_90_read(uint8_t addr)
{
        /* EC ports: 0x62/0x66 */
        send_ec_command(0x90);
        send_ec_data(addr);
        return recv_ec_data();
}
 
void ec_cmd_91_write(uint8_t addr, uint8_t data)
{
        /* EC ports: 0x62/0x66 */
        send_ec_command(0x91);
        send_ec_data(addr);
        send_ec_data(data);
}
 
uint8_t ec_cmd_94_query(void)
{
        send_ec_command(0x94);
        return recv_ec_data();
}
 
uint8_t ec_idx_read(uint16_t addr)
{
        outb((uint8_t) (addr >> 8), EC_INDEX_IO_HIGH_ADDR_PORT);
        outb((uint8_t) addr, EC_INDEX_IO_LOW_ADDR_PORT);
        return inb(EC_INDEX_IO_DATA_PORT);
}
 
void ec_idx_write(uint16_t addr, uint8_t data)
{
        outb((uint8_t) (addr >> 8), EC_INDEX_IO_HIGH_ADDR_PORT);
        outb((uint8_t) addr, EC_INDEX_IO_LOW_ADDR_PORT);
        outb(data, EC_INDEX_IO_DATA_PORT);
}
 
/* TODO: Check if ADC is valid. Are there 4, or actually 8 ADCs? */
uint16_t read_ec_adc_converter(uint8_t adc)
{
        uint8_t adc_converters_enabled; // Contains some ADCs and some DACs
        uint8_t idx_data;
        uint16_t adc_data;
 
        /* Backup enabled ADCs */
        adc_converters_enabled = ec_idx_read(0xff15);   // ADDAEN
 
        /* Enable desired ADC in bitmask (not enabled by EC FW, not used by vendor FW) */
        ec_idx_write(0xff15, adc_converters_enabled | ((1 << adc) & 0xf));      // ADDAEN
 
        /* Sample the desired ADC in binary field; OR the start bit */
        ec_idx_write(0xff18, ((adc << 1) & 0xf) | 1);   // ADCTRL
 
        /* Read the desired ADC */
        idx_data = ec_idx_read(0xff19); // ADCDAT
        adc_data = (idx_data << 2);
        /* Lower 2-bits of 10-bit ADC are in high bits of next register */
        idx_data = ec_idx_read(0xff1a); // ECIF
        adc_data |= ((idx_data & 0xc0) >> 6);
 
        /* Restore enabled ADCs */
        ec_idx_write(0xff15, adc_converters_enabled);   // ADDAEN
 
        return adc_data;
}