From b787bb126cbcd73754bcbc055ae9f804ac576e4a Mon Sep 17 00:00:00 2001 From: Nick Crews Date: Fri, 8 Feb 2019 17:37:18 -0700 Subject: platform/chrome: wilco_ec: Add support for raw commands in debugfs Add a debugfs attribute that allows sending raw commands to the EC. This is useful for development and debug but should not be enabled in a production environment. To test: Get the EC firmware build date First send the request command > echo 00 f0 38 00 03 00 > raw Then read the result. "12/21/18" is in the middle of the response > cat raw 00 31 32 2f 32 31 2f 31 38 00 00 0f 01 00 01 00 .12/21/18....... Get the EC firmware build date First send the request command > echo 00 f0 38 00 03 00 > raw Then read the result. "12/21/18" is in the middle of the response > cat raw 00 31 32 2f 32 31 2f 31 38 00 00 0f 01 00 01 00 .12/21/18....... Signed-off-by: Duncan Laurie Signed-off-by: Nick Crews [Fix off-by-one error in wilco_ec/debugfs.c] Reported-by: Dan Carpenter Signed-off-by: Enric Balletbo i Serra --- drivers/platform/chrome/wilco_ec/Kconfig | 10 ++ drivers/platform/chrome/wilco_ec/Makefile | 2 + drivers/platform/chrome/wilco_ec/core.c | 14 ++ drivers/platform/chrome/wilco_ec/debugfs.c | 238 +++++++++++++++++++++++++++++ 4 files changed, 264 insertions(+) create mode 100644 drivers/platform/chrome/wilco_ec/debugfs.c (limited to 'drivers/platform/chrome/wilco_ec') diff --git a/drivers/platform/chrome/wilco_ec/Kconfig b/drivers/platform/chrome/wilco_ec/Kconfig index c6bc4e8f3062..4a119ced4d0c 100644 --- a/drivers/platform/chrome/wilco_ec/Kconfig +++ b/drivers/platform/chrome/wilco_ec/Kconfig @@ -8,3 +8,13 @@ config WILCO_EC 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 index 03b32301dc61..063e7fb4ea17 100644 --- a/drivers/platform/chrome/wilco_ec/Makefile +++ b/drivers/platform/chrome/wilco_ec/Makefile @@ -2,3 +2,5 @@ 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 index 20ecc580d108..af5fd288b63b 100644 --- a/drivers/platform/chrome/wilco_ec/core.c +++ b/drivers/platform/chrome/wilco_ec/core.c @@ -69,11 +69,25 @@ static int wilco_ec_probe(struct platform_device *pdev) 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); + return 0; } static int wilco_ec_remove(struct platform_device *pdev) { + struct wilco_ec_device *ec = platform_get_drvdata(pdev); + + if (ec->debugfs_pdev) + platform_device_unregister(ec->debugfs_pdev); + /* Teardown cros_ec interface */ cros_ec_lpc_mec_destroy(); 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 +#include +#include +#include +#include +#include + +#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 "); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Wilco EC debugfs driver"); -- cgit v1.2.3-59-g8ed1b