390 строки
9.3 KiB
C
390 строки
9.3 KiB
C
/*
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* cros_ec_lpc - LPC access to the Chrome OS Embedded Controller
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*
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* Copyright (C) 2012-2015 Google, Inc
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* This driver uses the Chrome OS EC byte-level message-based protocol for
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* communicating the keyboard state (which keys are pressed) from a keyboard EC
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* to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing,
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* but everything else (including deghosting) is done here. The main
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* motivation for this is to keep the EC firmware as simple as possible, since
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* it cannot be easily upgraded and EC flash/IRAM space is relatively
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* expensive.
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*/
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#include <linux/dmi.h>
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#include <linux/delay.h>
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#include <linux/io.h>
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#include <linux/mfd/cros_ec.h>
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#include <linux/mfd/cros_ec_commands.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/printk.h>
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#define DRV_NAME "cros_ec_lpc"
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static int ec_response_timed_out(void)
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{
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unsigned long one_second = jiffies + HZ;
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usleep_range(200, 300);
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do {
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if (!(inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK))
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return 0;
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usleep_range(100, 200);
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} while (time_before(jiffies, one_second));
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return 1;
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}
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static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec,
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struct cros_ec_command *msg)
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{
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struct ec_host_request *request;
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struct ec_host_response response;
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u8 sum = 0;
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int i;
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int ret = 0;
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u8 *dout;
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ret = cros_ec_prepare_tx(ec, msg);
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/* Write buffer */
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for (i = 0; i < ret; i++)
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outb(ec->dout[i], EC_LPC_ADDR_HOST_PACKET + i);
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request = (struct ec_host_request *)ec->dout;
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/* Here we go */
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outb(EC_COMMAND_PROTOCOL_3, EC_LPC_ADDR_HOST_CMD);
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if (ec_response_timed_out()) {
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dev_warn(ec->dev, "EC responsed timed out\n");
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ret = -EIO;
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goto done;
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}
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/* Check result */
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msg->result = inb(EC_LPC_ADDR_HOST_DATA);
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ret = cros_ec_check_result(ec, msg);
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if (ret)
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goto done;
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/* Read back response */
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dout = (u8 *)&response;
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for (i = 0; i < sizeof(response); i++) {
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dout[i] = inb(EC_LPC_ADDR_HOST_PACKET + i);
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sum += dout[i];
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}
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msg->result = response.result;
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if (response.data_len > msg->insize) {
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dev_err(ec->dev,
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"packet too long (%d bytes, expected %d)",
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response.data_len, msg->insize);
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ret = -EMSGSIZE;
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goto done;
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}
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/* Read response and process checksum */
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for (i = 0; i < response.data_len; i++) {
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msg->data[i] =
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inb(EC_LPC_ADDR_HOST_PACKET + sizeof(response) + i);
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sum += msg->data[i];
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}
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if (sum) {
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dev_err(ec->dev,
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"bad packet checksum %02x\n",
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response.checksum);
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ret = -EBADMSG;
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goto done;
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}
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/* Return actual amount of data received */
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ret = response.data_len;
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done:
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return ret;
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}
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static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
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struct cros_ec_command *msg)
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{
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struct ec_lpc_host_args args;
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int csum;
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int i;
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int ret = 0;
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if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE ||
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msg->insize > EC_PROTO2_MAX_PARAM_SIZE) {
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dev_err(ec->dev,
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"invalid buffer sizes (out %d, in %d)\n",
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msg->outsize, msg->insize);
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return -EINVAL;
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}
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/* Now actually send the command to the EC and get the result */
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args.flags = EC_HOST_ARGS_FLAG_FROM_HOST;
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args.command_version = msg->version;
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args.data_size = msg->outsize;
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/* Initialize checksum */
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csum = msg->command + args.flags +
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args.command_version + args.data_size;
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/* Copy data and update checksum */
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for (i = 0; i < msg->outsize; i++) {
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outb(msg->data[i], EC_LPC_ADDR_HOST_PARAM + i);
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csum += msg->data[i];
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}
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/* Finalize checksum and write args */
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args.checksum = csum & 0xFF;
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outb(args.flags, EC_LPC_ADDR_HOST_ARGS);
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outb(args.command_version, EC_LPC_ADDR_HOST_ARGS + 1);
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outb(args.data_size, EC_LPC_ADDR_HOST_ARGS + 2);
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outb(args.checksum, EC_LPC_ADDR_HOST_ARGS + 3);
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/* Here we go */
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outb(msg->command, EC_LPC_ADDR_HOST_CMD);
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if (ec_response_timed_out()) {
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dev_warn(ec->dev, "EC responsed timed out\n");
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ret = -EIO;
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goto done;
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}
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/* Check result */
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msg->result = inb(EC_LPC_ADDR_HOST_DATA);
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ret = cros_ec_check_result(ec, msg);
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if (ret)
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goto done;
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/* Read back args */
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args.flags = inb(EC_LPC_ADDR_HOST_ARGS);
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args.command_version = inb(EC_LPC_ADDR_HOST_ARGS + 1);
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args.data_size = inb(EC_LPC_ADDR_HOST_ARGS + 2);
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args.checksum = inb(EC_LPC_ADDR_HOST_ARGS + 3);
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if (args.data_size > msg->insize) {
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dev_err(ec->dev,
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"packet too long (%d bytes, expected %d)",
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args.data_size, msg->insize);
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ret = -ENOSPC;
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goto done;
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}
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/* Start calculating response checksum */
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csum = msg->command + args.flags +
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args.command_version + args.data_size;
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/* Read response and update checksum */
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for (i = 0; i < args.data_size; i++) {
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msg->data[i] = inb(EC_LPC_ADDR_HOST_PARAM + i);
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csum += msg->data[i];
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}
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/* Verify checksum */
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if (args.checksum != (csum & 0xFF)) {
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dev_err(ec->dev,
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"bad packet checksum, expected %02x, got %02x\n",
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args.checksum, csum & 0xFF);
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ret = -EBADMSG;
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goto done;
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}
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/* Return actual amount of data received */
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ret = args.data_size;
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done:
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return ret;
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}
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/* Returns num bytes read, or negative on error. Doesn't need locking. */
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static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset,
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unsigned int bytes, void *dest)
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{
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int i = offset;
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char *s = dest;
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int cnt = 0;
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if (offset >= EC_MEMMAP_SIZE - bytes)
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return -EINVAL;
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/* fixed length */
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if (bytes) {
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for (; cnt < bytes; i++, s++, cnt++)
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*s = inb(EC_LPC_ADDR_MEMMAP + i);
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return cnt;
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}
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/* string */
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for (; i < EC_MEMMAP_SIZE; i++, s++) {
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*s = inb(EC_LPC_ADDR_MEMMAP + i);
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cnt++;
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if (!*s)
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break;
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}
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return cnt;
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}
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static int cros_ec_lpc_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct cros_ec_device *ec_dev;
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int ret;
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if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE,
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dev_name(dev))) {
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dev_err(dev, "couldn't reserve memmap region\n");
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return -EBUSY;
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}
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if ((inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) != 'E') ||
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(inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) != 'C')) {
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dev_err(dev, "EC ID not detected\n");
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return -ENODEV;
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}
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if (!devm_request_region(dev, EC_HOST_CMD_REGION0,
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EC_HOST_CMD_REGION_SIZE, dev_name(dev))) {
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dev_err(dev, "couldn't reserve region0\n");
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return -EBUSY;
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}
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if (!devm_request_region(dev, EC_HOST_CMD_REGION1,
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EC_HOST_CMD_REGION_SIZE, dev_name(dev))) {
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dev_err(dev, "couldn't reserve region1\n");
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return -EBUSY;
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}
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ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
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if (!ec_dev)
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return -ENOMEM;
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platform_set_drvdata(pdev, ec_dev);
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ec_dev->dev = dev;
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ec_dev->phys_name = dev_name(dev);
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ec_dev->cmd_xfer = cros_ec_cmd_xfer_lpc;
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ec_dev->pkt_xfer = cros_ec_pkt_xfer_lpc;
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ec_dev->cmd_readmem = cros_ec_lpc_readmem;
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ec_dev->din_size = sizeof(struct ec_host_response) +
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sizeof(struct ec_response_get_protocol_info);
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ec_dev->dout_size = sizeof(struct ec_host_request);
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ret = cros_ec_register(ec_dev);
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if (ret) {
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dev_err(dev, "couldn't register ec_dev (%d)\n", ret);
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return ret;
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}
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return 0;
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}
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static int cros_ec_lpc_remove(struct platform_device *pdev)
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{
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struct cros_ec_device *ec_dev;
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ec_dev = platform_get_drvdata(pdev);
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cros_ec_remove(ec_dev);
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return 0;
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}
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static struct dmi_system_id cros_ec_lpc_dmi_table[] __initdata = {
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{
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/*
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* Today all Chromebooks/boxes ship with Google_* as version and
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* coreboot as bios vendor. No other systems with this
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* combination are known to date.
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*/
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.matches = {
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DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
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DMI_MATCH(DMI_BIOS_VERSION, "Google_"),
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},
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},
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{
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/* x86-link, the Chromebook Pixel. */
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.matches = {
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DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
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DMI_MATCH(DMI_PRODUCT_NAME, "Link"),
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},
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},
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{
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/* x86-samus, the Chromebook Pixel 2. */
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.matches = {
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DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
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DMI_MATCH(DMI_PRODUCT_NAME, "Samus"),
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},
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},
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{
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/* x86-peppy, the Acer C720 Chromebook. */
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.matches = {
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DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
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DMI_MATCH(DMI_PRODUCT_NAME, "Peppy"),
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},
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},
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(dmi, cros_ec_lpc_dmi_table);
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static struct platform_driver cros_ec_lpc_driver = {
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.driver = {
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.name = DRV_NAME,
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},
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.probe = cros_ec_lpc_probe,
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.remove = cros_ec_lpc_remove,
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};
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static struct platform_device cros_ec_lpc_device = {
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.name = DRV_NAME
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};
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static int __init cros_ec_lpc_init(void)
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{
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int ret;
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if (!dmi_check_system(cros_ec_lpc_dmi_table)) {
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pr_err(DRV_NAME ": unsupported system.\n");
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return -ENODEV;
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}
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/* Register the driver */
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ret = platform_driver_register(&cros_ec_lpc_driver);
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if (ret) {
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pr_err(DRV_NAME ": can't register driver: %d\n", ret);
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return ret;
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}
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/* Register the device, and it'll get hooked up automatically */
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ret = platform_device_register(&cros_ec_lpc_device);
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if (ret) {
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pr_err(DRV_NAME ": can't register device: %d\n", ret);
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platform_driver_unregister(&cros_ec_lpc_driver);
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return ret;
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}
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return 0;
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}
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static void __exit cros_ec_lpc_exit(void)
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{
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platform_device_unregister(&cros_ec_lpc_device);
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platform_driver_unregister(&cros_ec_lpc_driver);
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}
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module_init(cros_ec_lpc_init);
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module_exit(cros_ec_lpc_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("ChromeOS EC LPC driver");
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