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