diff options
Diffstat (limited to 'drivers/platform/chrome/wilco_ec')
-rw-r--r-- | drivers/platform/chrome/wilco_ec/Kconfig | 20 | ||||
-rw-r--r-- | drivers/platform/chrome/wilco_ec/Makefile | 6 | ||||
-rw-r--r-- | drivers/platform/chrome/wilco_ec/core.c | 136 | ||||
-rw-r--r-- | drivers/platform/chrome/wilco_ec/debugfs.c | 238 | ||||
-rw-r--r-- | drivers/platform/chrome/wilco_ec/mailbox.c | 237 |
5 files changed, 637 insertions, 0 deletions
diff --git a/drivers/platform/chrome/wilco_ec/Kconfig b/drivers/platform/chrome/wilco_ec/Kconfig new file mode 100644 index 000000000000..e09e4cebe9b4 --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/Kconfig @@ -0,0 +1,20 @@ +config WILCO_EC + tristate "ChromeOS Wilco Embedded Controller" + depends on ACPI && X86 && CROS_EC_LPC && CROS_EC_LPC_MEC + help + If you say Y here, you get support for talking to the ChromeOS + Wilco EC over an eSPI bus. This uses a simple byte-level protocol + with a checksum. + + To compile this driver as a module, choose M here: the + module will be called wilco_ec. + +config WILCO_EC_DEBUGFS + tristate "Enable raw access to EC via debugfs" + depends on WILCO_EC + help + If you say Y here, you get support for sending raw commands to + the Wilco EC via debugfs. These commands do not do any byte + manipulation and allow for testing arbitrary commands. This + interface is intended for debug only and will not be present + on production devices. diff --git a/drivers/platform/chrome/wilco_ec/Makefile b/drivers/platform/chrome/wilco_ec/Makefile new file mode 100644 index 000000000000..063e7fb4ea17 --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0 + +wilco_ec-objs := core.o mailbox.o +obj-$(CONFIG_WILCO_EC) += wilco_ec.o +wilco_ec_debugfs-objs := debugfs.o +obj-$(CONFIG_WILCO_EC_DEBUGFS) += wilco_ec_debugfs.o diff --git a/drivers/platform/chrome/wilco_ec/core.c b/drivers/platform/chrome/wilco_ec/core.c new file mode 100644 index 000000000000..05e1e2be1c91 --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/core.c @@ -0,0 +1,136 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Core driver for Wilco Embedded Controller + * + * Copyright 2018 Google LLC + * + * This is the entry point for the drivers that control the Wilco EC. + * This driver is responsible for several tasks: + * - Initialize the register interface that is used by wilco_ec_mailbox() + * - Create a platform device which is picked up by the debugfs driver + * - Create a platform device which is picked up by the RTC driver + */ + +#include <linux/acpi.h> +#include <linux/device.h> +#include <linux/ioport.h> +#include <linux/module.h> +#include <linux/platform_data/wilco-ec.h> +#include <linux/platform_device.h> + +#include "../cros_ec_lpc_mec.h" + +#define DRV_NAME "wilco-ec" + +static struct resource *wilco_get_resource(struct platform_device *pdev, + int index) +{ + struct device *dev = &pdev->dev; + struct resource *res; + + res = platform_get_resource(pdev, IORESOURCE_IO, index); + if (!res) { + dev_dbg(dev, "Couldn't find IO resource %d\n", index); + return res; + } + + return devm_request_region(dev, res->start, resource_size(res), + dev_name(dev)); +} + +static int wilco_ec_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct wilco_ec_device *ec; + int ret; + + ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL); + if (!ec) + return -ENOMEM; + + platform_set_drvdata(pdev, ec); + ec->dev = dev; + mutex_init(&ec->mailbox_lock); + + /* Largest data buffer size requirement is extended data response */ + ec->data_size = sizeof(struct wilco_ec_response) + + EC_MAILBOX_DATA_SIZE_EXTENDED; + ec->data_buffer = devm_kzalloc(dev, ec->data_size, GFP_KERNEL); + if (!ec->data_buffer) + return -ENOMEM; + + /* Prepare access to IO regions provided by ACPI */ + ec->io_data = wilco_get_resource(pdev, 0); /* Host Data */ + ec->io_command = wilco_get_resource(pdev, 1); /* Host Command */ + ec->io_packet = wilco_get_resource(pdev, 2); /* MEC EMI */ + if (!ec->io_data || !ec->io_command || !ec->io_packet) + return -ENODEV; + + /* Initialize cros_ec register interface for communication */ + cros_ec_lpc_mec_init(ec->io_packet->start, + ec->io_packet->start + EC_MAILBOX_DATA_SIZE); + + /* + * Register a child device that will be found by the debugfs driver. + * Ignore failure. + */ + ec->debugfs_pdev = platform_device_register_data(dev, + "wilco-ec-debugfs", + PLATFORM_DEVID_AUTO, + NULL, 0); + + /* Register a child device that will be found by the RTC driver. */ + ec->rtc_pdev = platform_device_register_data(dev, "rtc-wilco-ec", + PLATFORM_DEVID_AUTO, + NULL, 0); + if (IS_ERR(ec->rtc_pdev)) { + dev_err(dev, "Failed to create RTC platform device\n"); + ret = PTR_ERR(ec->rtc_pdev); + goto unregister_debugfs; + } + + return 0; + +unregister_debugfs: + if (ec->debugfs_pdev) + platform_device_unregister(ec->debugfs_pdev); + cros_ec_lpc_mec_destroy(); + return ret; +} + +static int wilco_ec_remove(struct platform_device *pdev) +{ + struct wilco_ec_device *ec = platform_get_drvdata(pdev); + + platform_device_unregister(ec->rtc_pdev); + if (ec->debugfs_pdev) + platform_device_unregister(ec->debugfs_pdev); + + /* Teardown cros_ec interface */ + cros_ec_lpc_mec_destroy(); + + return 0; +} + +static const struct acpi_device_id wilco_ec_acpi_device_ids[] = { + { "GOOG000C", 0 }, + { } +}; +MODULE_DEVICE_TABLE(acpi, wilco_ec_acpi_device_ids); + +static struct platform_driver wilco_ec_driver = { + .driver = { + .name = DRV_NAME, + .acpi_match_table = wilco_ec_acpi_device_ids, + }, + .probe = wilco_ec_probe, + .remove = wilco_ec_remove, +}; + +module_platform_driver(wilco_ec_driver); + +MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>"); +MODULE_AUTHOR("Duncan Laurie <dlaurie@chromium.org>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("ChromeOS Wilco Embedded Controller driver"); +MODULE_ALIAS("platform:" DRV_NAME); diff --git a/drivers/platform/chrome/wilco_ec/debugfs.c b/drivers/platform/chrome/wilco_ec/debugfs.c new file mode 100644 index 000000000000..c090db2cd5be --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/debugfs.c @@ -0,0 +1,238 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * debugfs attributes for Wilco EC + * + * Copyright 2019 Google LLC + * + * There is only one attribute used for debugging, called raw. + * You can write a hexadecimal sentence to raw, and that series of bytes + * will be sent to the EC. Then, you can read the bytes of response + * by reading from raw. + * + * For writing: + * Bytes 0-1 indicate the message type: + * 00 F0 = Execute Legacy Command + * 00 F2 = Read/Write NVRAM Property + * Byte 2 provides the command code + * Bytes 3+ consist of the data passed in the request + * + * When referencing the EC interface spec, byte 2 corresponds to MBOX[0], + * byte 3 corresponds to MBOX[1], etc. + * + * At least three bytes are required, for the msg type and command, + * with additional bytes optional for additional data. + * + * Example: + * // Request EC info type 3 (EC firmware build date) + * $ echo 00 f0 38 00 03 00 > raw + * // View the result. The decoded ASCII result "12/21/18" is + * // included after the raw hex. + * $ cat raw + * 00 31 32 2f 32 31 2f 31 38 00 38 00 01 00 2f 00 .12/21/18.8... + */ + +#include <linux/ctype.h> +#include <linux/debugfs.h> +#include <linux/fs.h> +#include <linux/module.h> +#include <linux/platform_data/wilco-ec.h> +#include <linux/platform_device.h> + +#define DRV_NAME "wilco-ec-debugfs" + +/* The 256 raw bytes will take up more space when represented as a hex string */ +#define FORMATTED_BUFFER_SIZE (EC_MAILBOX_DATA_SIZE_EXTENDED * 4) + +struct wilco_ec_debugfs { + struct wilco_ec_device *ec; + struct dentry *dir; + size_t response_size; + u8 raw_data[EC_MAILBOX_DATA_SIZE_EXTENDED]; + u8 formatted_data[FORMATTED_BUFFER_SIZE]; +}; +static struct wilco_ec_debugfs *debug_info; + +/** + * parse_hex_sentence() - Convert a ascii hex representation into byte array. + * @in: Input buffer of ascii. + * @isize: Length of input buffer. + * @out: Output buffer. + * @osize: Length of output buffer, e.g. max number of bytes to parse. + * + * An valid input is a series of ascii hexadecimal numbers, separated by spaces. + * An example valid input is + * " 00 f2 0 000076 6 0 ff" + * + * If an individual "word" within the hex sentence is longer than MAX_WORD_SIZE, + * then the sentence is illegal, and parsing will fail. + * + * Return: Number of bytes parsed, or negative error code on failure. + */ +static int parse_hex_sentence(const char *in, int isize, u8 *out, int osize) +{ + int n_parsed = 0; + int word_start = 0; + int word_end; + int word_len; + /* Temp buffer for holding a "word" of chars that represents one byte */ + #define MAX_WORD_SIZE 16 + char tmp[MAX_WORD_SIZE + 1]; + u8 byte; + + while (word_start < isize && n_parsed < osize) { + /* Find the start of the next word */ + while (word_start < isize && isspace(in[word_start])) + word_start++; + /* reached the end of the input before next word? */ + if (word_start >= isize) + break; + + /* Find the end of this word */ + word_end = word_start; + while (word_end < isize && !isspace(in[word_end])) + word_end++; + + /* Copy to a tmp NULL terminated string */ + word_len = word_end - word_start; + if (word_len > MAX_WORD_SIZE) + return -EINVAL; + memcpy(tmp, in + word_start, word_len); + tmp[word_len] = '\0'; + + /* + * Convert from hex string, place in output. If fails to parse, + * just return -EINVAL because specific error code is only + * relevant for this one word, returning it would be confusing. + */ + if (kstrtou8(tmp, 16, &byte)) + return -EINVAL; + out[n_parsed++] = byte; + + word_start = word_end; + } + return n_parsed; +} + +/* The message type takes up two bytes*/ +#define TYPE_AND_DATA_SIZE ((EC_MAILBOX_DATA_SIZE) + 2) + +static ssize_t raw_write(struct file *file, const char __user *user_buf, + size_t count, loff_t *ppos) +{ + char *buf = debug_info->formatted_data; + struct wilco_ec_message msg; + u8 request_data[TYPE_AND_DATA_SIZE]; + ssize_t kcount; + int ret; + + if (count > FORMATTED_BUFFER_SIZE) + return -EINVAL; + + kcount = simple_write_to_buffer(buf, FORMATTED_BUFFER_SIZE, ppos, + user_buf, count); + if (kcount < 0) + return kcount; + + ret = parse_hex_sentence(buf, kcount, request_data, TYPE_AND_DATA_SIZE); + if (ret < 0) + return ret; + /* Need at least two bytes for message type and one for command */ + if (ret < 3) + return -EINVAL; + + /* Clear response data buffer */ + memset(debug_info->raw_data, '\0', EC_MAILBOX_DATA_SIZE_EXTENDED); + + msg.type = request_data[0] << 8 | request_data[1]; + msg.flags = WILCO_EC_FLAG_RAW; + msg.command = request_data[2]; + msg.request_data = ret > 3 ? request_data + 3 : 0; + msg.request_size = ret - 3; + msg.response_data = debug_info->raw_data; + msg.response_size = EC_MAILBOX_DATA_SIZE; + + /* Telemetry commands use extended response data */ + if (msg.type == WILCO_EC_MSG_TELEMETRY_LONG) { + msg.flags |= WILCO_EC_FLAG_EXTENDED_DATA; + msg.response_size = EC_MAILBOX_DATA_SIZE_EXTENDED; + } + + ret = wilco_ec_mailbox(debug_info->ec, &msg); + if (ret < 0) + return ret; + debug_info->response_size = ret; + + return count; +} + +static ssize_t raw_read(struct file *file, char __user *user_buf, size_t count, + loff_t *ppos) +{ + int fmt_len = 0; + + if (debug_info->response_size) { + fmt_len = hex_dump_to_buffer(debug_info->raw_data, + debug_info->response_size, + 16, 1, debug_info->formatted_data, + FORMATTED_BUFFER_SIZE, true); + /* Only return response the first time it is read */ + debug_info->response_size = 0; + } + + return simple_read_from_buffer(user_buf, count, ppos, + debug_info->formatted_data, fmt_len); +} + +static const struct file_operations fops_raw = { + .owner = THIS_MODULE, + .read = raw_read, + .write = raw_write, + .llseek = no_llseek, +}; + +/** + * wilco_ec_debugfs_probe() - Create the debugfs node + * @pdev: The platform device, probably created in core.c + * + * Try to create a debugfs node. If it fails, then we don't want to change + * behavior at all, this is for debugging after all. Just fail silently. + * + * Return: 0 always. + */ +static int wilco_ec_debugfs_probe(struct platform_device *pdev) +{ + struct wilco_ec_device *ec = dev_get_drvdata(pdev->dev.parent); + + debug_info = devm_kzalloc(&pdev->dev, sizeof(*debug_info), GFP_KERNEL); + if (!debug_info) + return 0; + debug_info->ec = ec; + debug_info->dir = debugfs_create_dir("wilco_ec", NULL); + if (!debug_info->dir) + return 0; + debugfs_create_file("raw", 0644, debug_info->dir, NULL, &fops_raw); + + return 0; +} + +static int wilco_ec_debugfs_remove(struct platform_device *pdev) +{ + debugfs_remove_recursive(debug_info->dir); + + return 0; +} + +static struct platform_driver wilco_ec_debugfs_driver = { + .driver = { + .name = DRV_NAME, + }, + .probe = wilco_ec_debugfs_probe, + .remove = wilco_ec_debugfs_remove, +}; + +module_platform_driver(wilco_ec_debugfs_driver); + +MODULE_ALIAS("platform:" DRV_NAME); +MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Wilco EC debugfs driver"); diff --git a/drivers/platform/chrome/wilco_ec/mailbox.c b/drivers/platform/chrome/wilco_ec/mailbox.c new file mode 100644 index 000000000000..f6ff29a11f1a --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/mailbox.c @@ -0,0 +1,237 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Mailbox interface for Wilco Embedded Controller + * + * Copyright 2018 Google LLC + * + * The Wilco EC is similar to a typical ChromeOS embedded controller. + * It uses the same MEC based low-level communication and a similar + * protocol, but with some important differences. The EC firmware does + * not support the same mailbox commands so it is not registered as a + * cros_ec device type. + * + * Most messages follow a standard format, but there are some exceptions + * and an interface is provided to do direct/raw transactions that do not + * make assumptions about byte placement. + */ + +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/platform_data/wilco-ec.h> +#include <linux/platform_device.h> + +#include "../cros_ec_lpc_mec.h" + +/* Version of mailbox interface */ +#define EC_MAILBOX_VERSION 0 + +/* Command to start mailbox transaction */ +#define EC_MAILBOX_START_COMMAND 0xda + +/* Version of EC protocol */ +#define EC_MAILBOX_PROTO_VERSION 3 + +/* Number of header bytes to be counted as data bytes */ +#define EC_MAILBOX_DATA_EXTRA 2 + +/* Maximum timeout */ +#define EC_MAILBOX_TIMEOUT HZ + +/* EC response flags */ +#define EC_CMDR_DATA BIT(0) /* Data ready for host to read */ +#define EC_CMDR_PENDING BIT(1) /* Write pending to EC */ +#define EC_CMDR_BUSY BIT(2) /* EC is busy processing a command */ +#define EC_CMDR_CMD BIT(3) /* Last host write was a command */ + +/** + * wilco_ec_response_timed_out() - Wait for EC response. + * @ec: EC device. + * + * Return: true if EC timed out, false if EC did not time out. + */ +static bool wilco_ec_response_timed_out(struct wilco_ec_device *ec) +{ + unsigned long timeout = jiffies + EC_MAILBOX_TIMEOUT; + + do { + if (!(inb(ec->io_command->start) & + (EC_CMDR_PENDING | EC_CMDR_BUSY))) + return false; + usleep_range(100, 200); + } while (time_before(jiffies, timeout)); + + return true; +} + +/** + * wilco_ec_checksum() - Compute 8-bit checksum over data range. + * @data: Data to checksum. + * @size: Number of bytes to checksum. + * + * Return: 8-bit checksum of provided data. + */ +static u8 wilco_ec_checksum(const void *data, size_t size) +{ + u8 *data_bytes = (u8 *)data; + u8 checksum = 0; + size_t i; + + for (i = 0; i < size; i++) + checksum += data_bytes[i]; + + return checksum; +} + +/** + * wilco_ec_prepare() - Prepare the request structure for the EC. + * @msg: EC message with request information. + * @rq: EC request structure to fill. + */ +static void wilco_ec_prepare(struct wilco_ec_message *msg, + struct wilco_ec_request *rq) +{ + memset(rq, 0, sizeof(*rq)); + + /* Handle messages without trimming bytes from the request */ + if (msg->request_size && msg->flags & WILCO_EC_FLAG_RAW_REQUEST) { + rq->reserved_raw = *(u8 *)msg->request_data; + msg->request_size--; + memmove(msg->request_data, msg->request_data + 1, + msg->request_size); + } + + /* Fill in request packet */ + rq->struct_version = EC_MAILBOX_PROTO_VERSION; + rq->mailbox_id = msg->type; + rq->mailbox_version = EC_MAILBOX_VERSION; + rq->data_size = msg->request_size + EC_MAILBOX_DATA_EXTRA; + rq->command = msg->command; + + /* Checksum header and data */ + rq->checksum = wilco_ec_checksum(rq, sizeof(*rq)); + rq->checksum += wilco_ec_checksum(msg->request_data, msg->request_size); + rq->checksum = -rq->checksum; +} + +/** + * wilco_ec_transfer() - Perform actual data transfer. + * @ec: EC device. + * @msg: EC message data for request and response. + * @rq: Filled in request structure + * + * Context: ec->mailbox_lock should be held while using this function. + * Return: number of bytes received or negative error code on failure. + */ +static int wilco_ec_transfer(struct wilco_ec_device *ec, + struct wilco_ec_message *msg, + struct wilco_ec_request *rq) +{ + struct wilco_ec_response *rs; + u8 checksum; + u8 flag; + size_t size; + + /* Write request header, then data */ + cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, 0, sizeof(*rq), (u8 *)rq); + cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, sizeof(*rq), msg->request_size, + msg->request_data); + + /* Start the command */ + outb(EC_MAILBOX_START_COMMAND, ec->io_command->start); + + /* For some commands (eg shutdown) the EC will not respond, that's OK */ + if (msg->flags & WILCO_EC_FLAG_NO_RESPONSE) { + dev_dbg(ec->dev, "EC does not respond to this command\n"); + return 0; + } + + /* Wait for it to complete */ + if (wilco_ec_response_timed_out(ec)) { + dev_dbg(ec->dev, "response timed out\n"); + return -ETIMEDOUT; + } + + /* Check result */ + flag = inb(ec->io_data->start); + if (flag) { + dev_dbg(ec->dev, "bad response: 0x%02x\n", flag); + return -EIO; + } + + if (msg->flags & WILCO_EC_FLAG_EXTENDED_DATA) + size = EC_MAILBOX_DATA_SIZE_EXTENDED; + else + size = EC_MAILBOX_DATA_SIZE; + + /* Read back response */ + rs = ec->data_buffer; + checksum = cros_ec_lpc_io_bytes_mec(MEC_IO_READ, 0, + sizeof(*rs) + size, (u8 *)rs); + if (checksum) { + dev_dbg(ec->dev, "bad packet checksum 0x%02x\n", rs->checksum); + return -EBADMSG; + } + + /* Check that the EC reported success */ + msg->result = rs->result; + if (msg->result) { + dev_dbg(ec->dev, "bad response: 0x%02x\n", msg->result); + return -EBADMSG; + } + + /* Check the returned data size, skipping the header */ + if (rs->data_size != size) { + dev_dbg(ec->dev, "unexpected packet size (%u != %zu)", + rs->data_size, size); + return -EMSGSIZE; + } + + /* Skip 1 response data byte unless specified */ + size = (msg->flags & WILCO_EC_FLAG_RAW_RESPONSE) ? 0 : 1; + if ((ssize_t) rs->data_size - size < msg->response_size) { + dev_dbg(ec->dev, "response data too short (%zd < %zu)", + (ssize_t) rs->data_size - size, msg->response_size); + return -EMSGSIZE; + } + + /* Ignore response data bytes as requested */ + memcpy(msg->response_data, rs->data + size, msg->response_size); + + /* Return actual amount of data received */ + return msg->response_size; +} + +/** + * wilco_ec_mailbox() - Send EC request and receive EC response. + * @ec: EC device. + * @msg: EC message data for request and response. + * + * On entry msg->type, msg->flags, msg->command, msg->request_size, + * msg->response_size, and msg->request_data should all be filled in. + * + * On exit msg->result and msg->response_data will be filled. + * + * Return: number of bytes received or negative error code on failure. + */ +int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg) +{ + struct wilco_ec_request *rq; + int ret; + + dev_dbg(ec->dev, "cmd=%02x type=%04x flags=%02x rslen=%zu rqlen=%zu\n", + msg->command, msg->type, msg->flags, msg->response_size, + msg->request_size); + + /* Prepare request packet */ + rq = ec->data_buffer; + wilco_ec_prepare(msg, rq); + + mutex_lock(&ec->mailbox_lock); + ret = wilco_ec_transfer(ec, msg, rq); + mutex_unlock(&ec->mailbox_lock); + + return ret; + +} +EXPORT_SYMBOL_GPL(wilco_ec_mailbox); |