LXR uboot/drivers/misc/cros_ec

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Chromium OS cros_ec driver - LPC interface
   4 *
   5 * Copyright (c) 2012 The Chromium OS Authors.
   6 */
   7
   8/*
   9 * The Matrix Keyboard Protocol driver handles talking to the keyboard
  10 * controller chip. Mostly this is for keyboard functions, but some other
  11 * things have slipped in, so we provide generic services to talk to the
  12 * KBC.
  13 */
  14
  15#include <common.h>
  16#include <dm.h>
  17#include <command.h>
  18#include <cros_ec.h>
  19#include <log.h>
  20#include <asm/io.h>
  21
  22#ifdef DEBUG_TRACE
  23#define debug_trace(fmt, b...)  debug(fmt, ##b)
  24#else
  25#define debug_trace(fmt, b...)
  26#endif
  27
  28/* Timeout waiting for a flash erase command to complete */
  29static const int CROS_EC_CMD_TIMEOUT_MS = 5000;
  30
  31static int wait_for_sync(struct cros_ec_dev *dev)
  32{
  33        unsigned long start;
  34
  35        start = get_timer(0);
  36        while (inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK) {
  37                if (get_timer(start) > CROS_EC_CMD_TIMEOUT_MS) {
  38                        debug("%s: Timeout waiting for CROS_EC sync\n",
  39                              __func__);
  40                        return -1;
  41                }
  42        }
  43
  44        return 0;
  45}
  46
  47int cros_ec_lpc_packet(struct udevice *udev, int out_bytes, int in_bytes)
  48{
  49        struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
  50        uint8_t *d;
  51        int i;
  52
  53        if (out_bytes > EC_LPC_HOST_PACKET_SIZE)
  54                return log_msg_ret("Cannot send that many bytes\n", -E2BIG);
  55
  56        if (in_bytes > EC_LPC_HOST_PACKET_SIZE)
  57                return log_msg_ret("Cannot receive that many bytes\n", -E2BIG);
  58
  59        if (wait_for_sync(dev))
  60                return log_msg_ret("Timeout waiting ready\n", -ETIMEDOUT);
  61
  62        /* Write data */
  63        for (i = 0, d = (uint8_t *)dev->dout; i < out_bytes; i++, d++)
  64                outb(*d, EC_LPC_ADDR_HOST_PACKET + i);
  65
  66        /* Start the command */
  67        outb(EC_COMMAND_PROTOCOL_3, EC_LPC_ADDR_HOST_CMD);
  68
  69        if (wait_for_sync(dev))
  70                return log_msg_ret("Timeout waiting ready\n", -ETIMEDOUT);
  71
  72        /* Read back args */
  73        for (i = 0, d = dev->din; i < in_bytes; i++, d++)
  74                *d = inb(EC_LPC_ADDR_HOST_PACKET + i);
  75
  76        return in_bytes;
  77}
  78
  79int cros_ec_lpc_command(struct udevice *udev, uint8_t cmd, int cmd_version,
  80                     const uint8_t *dout, int dout_len,
  81                     uint8_t **dinp, int din_len)
  82{
  83        struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
  84        const int cmd_addr = EC_LPC_ADDR_HOST_CMD;
  85        const int data_addr = EC_LPC_ADDR_HOST_DATA;
  86        const int args_addr = EC_LPC_ADDR_HOST_ARGS;
  87        const int param_addr = EC_LPC_ADDR_HOST_PARAM;
  88
  89        struct ec_lpc_host_args args;
  90        uint8_t *d;
  91        int csum;
  92        int i;
  93
  94        if (dout_len > EC_PROTO2_MAX_PARAM_SIZE) {
  95                debug("%s: Cannot send %d bytes\n", __func__, dout_len);
  96                return -1;
  97        }
  98
  99        /* Fill in args */
 100        args.flags = EC_HOST_ARGS_FLAG_FROM_HOST;
 101        args.command_version = cmd_version;
 102        args.data_size = dout_len;
 103
 104        /* Calculate checksum */
 105        csum = cmd + args.flags + args.command_version + args.data_size;
 106        for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++)
 107                csum += *d;
 108
 109        args.checksum = (uint8_t)csum;
 110
 111        if (wait_for_sync(dev)) {
 112                debug("%s: Timeout waiting ready\n", __func__);
 113                return -1;
 114        }
 115
 116        /* Write args */
 117        for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++)
 118                outb(*d, args_addr + i);
 119
 120        /* Write data, if any */
 121        debug_trace("cmd: %02x, ver: %02x", cmd, cmd_version);
 122        for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) {
 123                outb(*d, param_addr + i);
 124                debug_trace("%02x ", *d);
 125        }
 126
 127        outb(cmd, cmd_addr);
 128        debug_trace("\n");
 129
 130        if (wait_for_sync(dev)) {
 131                debug("%s: Timeout waiting for response\n", __func__);
 132                return -1;
 133        }
 134
 135        /* Check result */
 136        i = inb(data_addr);
 137        if (i) {
 138                debug("%s: CROS_EC result code %d\n", __func__, i);
 139                return -i;
 140        }
 141
 142        /* Read back args */
 143        for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++)
 144                *d = inb(args_addr + i);
 145
 146        /*
 147         * If EC didn't modify args flags, then somehow we sent a new-style
 148         * command to an old EC, which means it would have read its params
 149         * from the wrong place.
 150         */
 151        if (!(args.flags & EC_HOST_ARGS_FLAG_TO_HOST)) {
 152                debug("%s: CROS_EC protocol mismatch\n", __func__);
 153                return -EC_RES_INVALID_RESPONSE;
 154        }
 155
 156        if (args.data_size > din_len) {
 157                debug("%s: CROS_EC returned too much data %d > %d\n",
 158                      __func__, args.data_size, din_len);
 159                return -EC_RES_INVALID_RESPONSE;
 160        }
 161
 162        /* Read data, if any */
 163        for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) {
 164                *d = inb(param_addr + i);
 165                debug_trace("%02x ", *d);
 166        }
 167        debug_trace("\n");
 168
 169        /* Verify checksum */
 170        csum = cmd + args.flags + args.command_version + args.data_size;
 171        for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++)
 172                csum += *d;
 173
 174        if (args.checksum != (uint8_t)csum) {
 175                debug("%s: CROS_EC response has invalid checksum\n", __func__);
 176                return -EC_RES_INVALID_CHECKSUM;
 177        }
 178        *dinp = dev->din;
 179
 180        /* Return actual amount of data received */
 181        return args.data_size;
 182}
 183
 184/**
 185 * Initialize LPC protocol.
 186 *
 187 * @param dev           CROS_EC device
 188 * @param blob          Device tree blob
 189 * @return 0 if ok, -1 on error
 190 */
 191int cros_ec_lpc_init(struct cros_ec_dev *dev, const void *blob)
 192{
 193        int byte, i;
 194
 195        /* See if we can find an EC at the other end */
 196        byte = 0xff;
 197        byte &= inb(EC_LPC_ADDR_HOST_CMD);
 198        byte &= inb(EC_LPC_ADDR_HOST_DATA);
 199        for (i = 0; i < EC_PROTO2_MAX_PARAM_SIZE && (byte == 0xff); i++)
 200                byte &= inb(EC_LPC_ADDR_HOST_PARAM + i);
 201        if (byte == 0xff) {
 202                debug("%s: CROS_EC device not found on LPC bus\n",
 203                        __func__);
 204                return -1;
 205        }
 206
 207        return 0;
 208}
 209
 210/* Return the byte of EC switch states */
 211static int cros_ec_lpc_get_switches(struct udevice *dev)
 212{
 213        return inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SWITCHES);
 214}
 215
 216/*
 217 * Test if LPC command args are supported.
 218 *
 219 * The cheapest way to do this is by looking for the memory-mapped
 220 * flag.  This is faster than sending a new-style 'hello' command and
 221 * seeing whether the EC sets the EC_HOST_ARGS_FLAG_FROM_HOST flag
 222 * in args when it responds.
 223 */
 224static int cros_ec_lpc_check_version(struct udevice *dev)
 225{
 226        if (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) == 'E' &&
 227                        inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1)
 228                                == 'C' &&
 229                        (inb(EC_LPC_ADDR_MEMMAP +
 230                                EC_MEMMAP_HOST_CMD_FLAGS) &
 231                                EC_HOST_CMD_FLAG_LPC_ARGS_SUPPORTED)) {
 232                return 0;
 233        }
 234
 235        printf("%s: ERROR: old EC interface not supported\n", __func__);
 236        return -1;
 237}
 238
 239static int cros_ec_probe(struct udevice *dev)
 240{
 241        return cros_ec_register(dev);
 242}
 243
 244static struct dm_cros_ec_ops cros_ec_ops = {
 245        .packet = cros_ec_lpc_packet,
 246        .command = cros_ec_lpc_command,
 247        .check_version = cros_ec_lpc_check_version,
 248        .get_switches = cros_ec_lpc_get_switches,
 249};
 250
 251static const struct udevice_id cros_ec_ids[] = {
 252        { .compatible = "google,cros-ec-lpc" },
 253        { }
 254};
 255
 256U_BOOT_DRIVER(google_cros_ec_lpc) = {
 257        .name           = "google_cros_ec_lpc",
 258        .id             = UCLASS_CROS_EC,
 259        .of_match       = cros_ec_ids,
 260        .probe          = cros_ec_probe,
 261        .ops            = &cros_ec_ops,
 262};
 263