drivers/misc/cros_ec_lpc.c

   1 /*
   2  * Chromium OS cros_ec driver - LPC interface
   3  *
   4  * Copyright (c) 2012 The Chromium OS Authors.
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 /*
  10  * The Matrix Keyboard Protocol driver handles talking to the keyboard
  11  * controller chip. Mostly this is for keyboard functions, but some other
  12  * things have slipped in, so we provide generic services to talk to the
  13  * KBC.
  14  */
  15
  16 #include <common.h>
  17 #include <dm.h>
  18 #include <command.h>
  19 #include <cros_ec.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 static int wait_for_sync(struct cros_ec_dev *dev)
  29 {
  30         unsigned long start;
  31
  32         start = get_timer(0);
  33         while (inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK) {
  34                 if (get_timer(start) > 1000) {
  35                         debug("%s: Timeout waiting for CROS_EC sync\n",
  36                               __func__);
  37                         return -1;
  38                 }
  39         }
  40
  41         return 0;
  42 }
  43
  44 #ifdef CONFIG_DM_CROS_EC
  45 int cros_ec_lpc_command(struct udevice *udev, uint8_t cmd, int cmd_version,
  46                      const uint8_t *dout, int dout_len,
  47                      uint8_t **dinp, int din_len)
  48 {
  49         struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
  50 #else
  51 int cros_ec_lpc_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
  52                      const uint8_t *dout, int dout_len,
  53                      uint8_t **dinp, int din_len)
  54 {
  55 #endif
  56         const int cmd_addr = EC_LPC_ADDR_HOST_CMD;
  57         const int data_addr = EC_LPC_ADDR_HOST_DATA;
  58         const int args_addr = EC_LPC_ADDR_HOST_ARGS;
  59         const int param_addr = EC_LPC_ADDR_HOST_PARAM;
  60
  61         struct ec_lpc_host_args args;
  62         uint8_t *d;
  63         int csum;
  64         int i;
  65
  66         if (dout_len > EC_PROTO2_MAX_PARAM_SIZE) {
  67                 debug("%s: Cannot send %d bytes\n", __func__, dout_len);
  68                 return -1;
  69         }
  70
  71         /* Fill in args */
  72         args.flags = EC_HOST_ARGS_FLAG_FROM_HOST;
  73         args.command_version = cmd_version;
  74         args.data_size = dout_len;
  75
  76         /* Calculate checksum */
  77         csum = cmd + args.flags + args.command_version + args.data_size;
  78         for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++)
  79                 csum += *d;
  80
  81         args.checksum = (uint8_t)csum;
  82
  83         if (wait_for_sync(dev)) {
  84                 debug("%s: Timeout waiting ready\n", __func__);
  85                 return -1;
  86         }
  87
  88         /* Write args */
  89         for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++)
  90                 outb(*d, args_addr + i);
  91
  92         /* Write data, if any */
  93         debug_trace("cmd: %02x, ver: %02x", cmd, cmd_version);
  94         for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) {
  95                 outb(*d, param_addr + i);
  96                 debug_trace("%02x ", *d);
  97         }
  98
  99         outb(cmd, cmd_addr);
 100         debug_trace("\n");
 101
 102         if (wait_for_sync(dev)) {
 103                 debug("%s: Timeout waiting for response\n", __func__);
 104                 return -1;
 105         }
 106
 107         /* Check result */
 108         i = inb(data_addr);
 109         if (i) {
 110                 debug("%s: CROS_EC result code %d\n", __func__, i);
 111                 return -i;
 112         }
 113
 114         /* Read back args */
 115         for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++)
 116                 *d = inb(args_addr + i);
 117
 118         /*
 119          * If EC didn't modify args flags, then somehow we sent a new-style
 120          * command to an old EC, which means it would have read its params
 121          * from the wrong place.
 122          */
 123         if (!(args.flags & EC_HOST_ARGS_FLAG_TO_HOST)) {
 124                 debug("%s: CROS_EC protocol mismatch\n", __func__);
 125                 return -EC_RES_INVALID_RESPONSE;
 126         }
 127
 128         if (args.data_size > din_len) {
 129                 debug("%s: CROS_EC returned too much data %d > %d\n",
 130                       __func__, args.data_size, din_len);
 131                 return -EC_RES_INVALID_RESPONSE;
 132         }
 133
 134         /* Read data, if any */
 135         for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) {
 136                 *d = inb(param_addr + i);
 137                 debug_trace("%02x ", *d);
 138         }
 139         debug_trace("\n");
 140
 141         /* Verify checksum */
 142         csum = cmd + args.flags + args.command_version + args.data_size;
 143         for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++)
 144                 csum += *d;
 145
 146         if (args.checksum != (uint8_t)csum) {
 147                 debug("%s: CROS_EC response has invalid checksum\n", __func__);
 148                 return -EC_RES_INVALID_CHECKSUM;
 149         }
 150         *dinp = dev->din;
 151
 152         /* Return actual amount of data received */
 153         return args.data_size;
 154 }
 155
 156 /**
 157  * Initialize LPC protocol.
 158  *
 159  * @param dev           CROS_EC device
 160  * @param blob          Device tree blob
 161  * @return 0 if ok, -1 on error
 162  */
 163 int cros_ec_lpc_init(struct cros_ec_dev *dev, const void *blob)
 164 {
 165         int byte, i;
 166
 167         /* See if we can find an EC at the other end */
 168         byte = 0xff;
 169         byte &= inb(EC_LPC_ADDR_HOST_CMD);
 170         byte &= inb(EC_LPC_ADDR_HOST_DATA);
 171         for (i = 0; i < EC_PROTO2_MAX_PARAM_SIZE && (byte == 0xff); i++)
 172                 byte &= inb(EC_LPC_ADDR_HOST_PARAM + i);
 173         if (byte == 0xff) {
 174                 debug("%s: CROS_EC device not found on LPC bus\n",
 175                         __func__);
 176                 return -1;
 177         }
 178
 179         return 0;
 180 }
 181
 182 /*
 183  * Test if LPC command args are supported.
 184  *
 185  * The cheapest way to do this is by looking for the memory-mapped
 186  * flag.  This is faster than sending a new-style 'hello' command and
 187  * seeing whether the EC sets the EC_HOST_ARGS_FLAG_FROM_HOST flag
 188  * in args when it responds.
 189  */
 190 #ifdef CONFIG_DM_CROS_EC
 191 static int cros_ec_lpc_check_version(struct udevice *dev)
 192 #else
 193 int cros_ec_lpc_check_version(struct cros_ec_dev *dev)
 194 #endif
 195 {
 196         if (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) == 'E' &&
 197                         inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1)
 198                                 == 'C' &&
 199                         (inb(EC_LPC_ADDR_MEMMAP +
 200                                 EC_MEMMAP_HOST_CMD_FLAGS) &
 201                                 EC_HOST_CMD_FLAG_LPC_ARGS_SUPPORTED)) {
 202                 return 0;
 203         }
 204
 205         printf("%s: ERROR: old EC interface not supported\n", __func__);
 206         return -1;
 207 }
 208
 209 #ifdef CONFIG_DM_CROS_EC
 210 static int cros_ec_probe(struct udevice *dev)
 211 {
 212         return cros_ec_register(dev);
 213 }
 214
 215 static struct dm_cros_ec_ops cros_ec_ops = {
 216         .command = cros_ec_lpc_command,
 217         .check_version = cros_ec_lpc_check_version,
 218 };
 219
 220 static const struct udevice_id cros_ec_ids[] = {
 221         { .compatible = "google,cros-ec" },
 222         { }
 223 };
 224
 225 U_BOOT_DRIVER(cros_ec_lpc) = {
 226         .name           = "cros_ec",
 227         .id             = UCLASS_CROS_EC,
 228         .of_match       = cros_ec_ids,
 229         .probe          = cros_ec_probe,
 230         .ops            = &cros_ec_ops,
 231 };
 232 #endif