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600 lines
15 KiB
600 lines
15 KiB
// SPDX-License-Identifier: GPL-2.0 |
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// LPC interface for ChromeOS 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 driver uses the ChromeOS 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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#include <linux/acpi.h> |
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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/interrupt.h> |
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#include <linux/module.h> |
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#include <linux/platform_data/cros_ec_commands.h> |
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#include <linux/platform_data/cros_ec_proto.h> |
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#include <linux/platform_device.h> |
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#include <linux/printk.h> |
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#include <linux/suspend.h> |
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#include "cros_ec.h" |
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#include "cros_ec_lpc_mec.h" |
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|
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#define DRV_NAME "cros_ec_lpcs" |
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#define ACPI_DRV_NAME "GOOG0004" |
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|
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/* True if ACPI device is present */ |
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static bool cros_ec_lpc_acpi_device_found; |
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|
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/** |
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* struct lpc_driver_ops - LPC driver operations |
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* @read: Copy length bytes from EC address offset into buffer dest. Returns |
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* the 8-bit checksum of all bytes read. |
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* @write: Copy length bytes from buffer msg into EC address offset. Returns |
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* the 8-bit checksum of all bytes written. |
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*/ |
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struct lpc_driver_ops { |
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u8 (*read)(unsigned int offset, unsigned int length, u8 *dest); |
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u8 (*write)(unsigned int offset, unsigned int length, const u8 *msg); |
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}; |
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static struct lpc_driver_ops cros_ec_lpc_ops = { }; |
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|
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/* |
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* A generic instance of the read function of struct lpc_driver_ops, used for |
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* the LPC EC. |
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*/ |
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static u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, |
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u8 *dest) |
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{ |
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int sum = 0; |
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int i; |
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for (i = 0; i < length; ++i) { |
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dest[i] = inb(offset + i); |
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sum += dest[i]; |
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} |
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|
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/* Return checksum of all bytes read */ |
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return sum; |
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} |
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/* |
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* A generic instance of the write function of struct lpc_driver_ops, used for |
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* the LPC EC. |
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*/ |
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static u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, |
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const u8 *msg) |
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{ |
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int sum = 0; |
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int i; |
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for (i = 0; i < length; ++i) { |
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outb(msg[i], offset + i); |
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sum += msg[i]; |
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} |
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/* Return checksum of all bytes written */ |
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return sum; |
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} |
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/* |
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* An instance of the read function of struct lpc_driver_ops, used for the |
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* MEC variant of LPC EC. |
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*/ |
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static u8 cros_ec_lpc_mec_read_bytes(unsigned int offset, unsigned int length, |
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u8 *dest) |
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{ |
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int in_range = cros_ec_lpc_mec_in_range(offset, length); |
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if (in_range < 0) |
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return 0; |
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return in_range ? |
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cros_ec_lpc_io_bytes_mec(MEC_IO_READ, |
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offset - EC_HOST_CMD_REGION0, |
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length, dest) : |
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cros_ec_lpc_read_bytes(offset, length, dest); |
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} |
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|
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/* |
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* An instance of the write function of struct lpc_driver_ops, used for the |
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* MEC variant of LPC EC. |
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*/ |
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static u8 cros_ec_lpc_mec_write_bytes(unsigned int offset, unsigned int length, |
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const u8 *msg) |
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{ |
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int in_range = cros_ec_lpc_mec_in_range(offset, length); |
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if (in_range < 0) |
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return 0; |
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return in_range ? |
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cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, |
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offset - EC_HOST_CMD_REGION0, |
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length, (u8 *)msg) : |
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cros_ec_lpc_write_bytes(offset, length, msg); |
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} |
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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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u8 data; |
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usleep_range(200, 300); |
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do { |
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if (!(cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_CMD, 1, &data) & |
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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_response response; |
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u8 sum; |
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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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cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PACKET, ret, ec->dout); |
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/* Here we go */ |
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sum = EC_COMMAND_PROTOCOL_3; |
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cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum); |
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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 = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum); |
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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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sum = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET, sizeof(response), |
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dout); |
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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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sum += cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET + |
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sizeof(response), response.data_len, |
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msg->data); |
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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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u8 sum; |
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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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|
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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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sum = msg->command + args.flags + args.command_version + args.data_size; |
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/* Copy data and update checksum */ |
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sum += cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PARAM, msg->outsize, |
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msg->data); |
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/* Finalize checksum and write args */ |
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args.checksum = sum; |
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cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_ARGS, sizeof(args), |
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(u8 *)&args); |
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/* Here we go */ |
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sum = msg->command; |
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cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum); |
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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 = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum); |
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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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cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_ARGS, sizeof(args), (u8 *)&args); |
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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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sum = msg->command + args.flags + args.command_version + args.data_size; |
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/* Read response and update checksum */ |
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sum += cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PARAM, args.data_size, |
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msg->data); |
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/* Verify checksum */ |
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if (args.checksum != sum) { |
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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, sum); |
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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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cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + offset, bytes, s); |
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return bytes; |
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} |
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/* string */ |
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for (; i < EC_MEMMAP_SIZE; i++, s++) { |
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cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + i, 1, s); |
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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 void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data) |
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{ |
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struct cros_ec_device *ec_dev = data; |
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bool ec_has_more_events; |
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int ret; |
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ec_dev->last_event_time = cros_ec_get_time_ns(); |
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if (ec_dev->mkbp_event_supported) |
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do { |
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ret = cros_ec_get_next_event(ec_dev, NULL, |
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&ec_has_more_events); |
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if (ret > 0) |
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blocking_notifier_call_chain( |
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&ec_dev->event_notifier, 0, |
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ec_dev); |
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} while (ec_has_more_events); |
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if (value == ACPI_NOTIFY_DEVICE_WAKE) |
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pm_system_wakeup(); |
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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 acpi_device *adev; |
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acpi_status status; |
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struct cros_ec_device *ec_dev; |
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u8 buf[2]; |
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int irq, 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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/* |
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* Read the mapped ID twice, the first one is assuming the |
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* EC is a Microchip Embedded Controller (MEC) variant, if the |
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* protocol fails, fallback to the non MEC variant and try to |
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* read again the ID. |
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*/ |
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cros_ec_lpc_ops.read = cros_ec_lpc_mec_read_bytes; |
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cros_ec_lpc_ops.write = cros_ec_lpc_mec_write_bytes; |
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cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, buf); |
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if (buf[0] != 'E' || buf[1] != 'C') { |
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/* Re-assign read/write operations for the non MEC variant */ |
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cros_ec_lpc_ops.read = cros_ec_lpc_read_bytes; |
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cros_ec_lpc_ops.write = cros_ec_lpc_write_bytes; |
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cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, |
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buf); |
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if (buf[0] != 'E' || buf[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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} |
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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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|
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/* |
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* Some boards do not have an IRQ allotted for cros_ec_lpc, |
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* which makes ENXIO an expected (and safe) scenario. |
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*/ |
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irq = platform_get_irq_optional(pdev, 0); |
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if (irq > 0) |
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ec_dev->irq = irq; |
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else if (irq != -ENXIO) { |
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dev_err(dev, "couldn't retrieve IRQ number (%d)\n", irq); |
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return irq; |
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} |
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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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/* |
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* Connect a notify handler to process MKBP messages if we have a |
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* companion ACPI device. |
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*/ |
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adev = ACPI_COMPANION(dev); |
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if (adev) { |
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status = acpi_install_notify_handler(adev->handle, |
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ACPI_ALL_NOTIFY, |
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cros_ec_lpc_acpi_notify, |
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ec_dev); |
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if (ACPI_FAILURE(status)) |
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dev_warn(dev, "Failed to register notifier %08x\n", |
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status); |
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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 = platform_get_drvdata(pdev); |
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struct acpi_device *adev; |
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adev = ACPI_COMPANION(&pdev->dev); |
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if (adev) |
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acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY, |
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cros_ec_lpc_acpi_notify); |
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return cros_ec_unregister(ec_dev); |
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} |
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static const struct acpi_device_id cros_ec_lpc_acpi_device_ids[] = { |
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{ ACPI_DRV_NAME, 0 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(acpi, cros_ec_lpc_acpi_device_ids); |
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|
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static const struct dmi_system_id cros_ec_lpc_dmi_table[] __initconst = { |
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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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/* |
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* If the box is running custom coreboot firmware then the |
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* DMI BIOS version string will not be matched by "Google_", |
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* but the system vendor string will still be matched by |
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* "GOOGLE". |
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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_SYS_VENDOR, "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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{ |
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/* x86-glimmer, the Lenovo Thinkpad Yoga 11e. */ |
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.matches = { |
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DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"), |
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DMI_MATCH(DMI_PRODUCT_NAME, "Glimmer"), |
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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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|
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#ifdef CONFIG_PM_SLEEP |
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static int cros_ec_lpc_suspend(struct device *dev) |
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{ |
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struct cros_ec_device *ec_dev = dev_get_drvdata(dev); |
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|
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return cros_ec_suspend(ec_dev); |
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} |
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|
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static int cros_ec_lpc_resume(struct device *dev) |
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{ |
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struct cros_ec_device *ec_dev = dev_get_drvdata(dev); |
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|
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return cros_ec_resume(ec_dev); |
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} |
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#endif |
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|
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static const struct dev_pm_ops cros_ec_lpc_pm_ops = { |
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SET_LATE_SYSTEM_SLEEP_PM_OPS(cros_ec_lpc_suspend, cros_ec_lpc_resume) |
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}; |
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|
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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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.acpi_match_table = cros_ec_lpc_acpi_device_ids, |
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.pm = &cros_ec_lpc_pm_ops, |
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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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|
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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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|
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static acpi_status cros_ec_lpc_parse_device(acpi_handle handle, u32 level, |
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void *context, void **retval) |
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{ |
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*(bool *)context = true; |
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return AE_CTRL_TERMINATE; |
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} |
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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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acpi_status status; |
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|
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status = acpi_get_devices(ACPI_DRV_NAME, cros_ec_lpc_parse_device, |
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&cros_ec_lpc_acpi_device_found, NULL); |
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if (ACPI_FAILURE(status)) |
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pr_warn(DRV_NAME ": Looking for %s failed\n", ACPI_DRV_NAME); |
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|
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if (!cros_ec_lpc_acpi_device_found && |
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!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; |
|
} |
|
|
|
cros_ec_lpc_mec_init(EC_HOST_CMD_REGION0, |
|
EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SIZE); |
|
|
|
/* Register the driver */ |
|
ret = platform_driver_register(&cros_ec_lpc_driver); |
|
if (ret) { |
|
pr_err(DRV_NAME ": can't register driver: %d\n", ret); |
|
cros_ec_lpc_mec_destroy(); |
|
return ret; |
|
} |
|
|
|
if (!cros_ec_lpc_acpi_device_found) { |
|
/* Register the device, and it'll get hooked up automatically */ |
|
ret = platform_device_register(&cros_ec_lpc_device); |
|
if (ret) { |
|
pr_err(DRV_NAME ": can't register device: %d\n", ret); |
|
platform_driver_unregister(&cros_ec_lpc_driver); |
|
cros_ec_lpc_mec_destroy(); |
|
} |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
static void __exit cros_ec_lpc_exit(void) |
|
{ |
|
if (!cros_ec_lpc_acpi_device_found) |
|
platform_device_unregister(&cros_ec_lpc_device); |
|
platform_driver_unregister(&cros_ec_lpc_driver); |
|
cros_ec_lpc_mec_destroy(); |
|
} |
|
|
|
module_init(cros_ec_lpc_init); |
|
module_exit(cros_ec_lpc_exit); |
|
|
|
MODULE_LICENSE("GPL"); |
|
MODULE_DESCRIPTION("ChromeOS EC LPC driver");
|
|
|