| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * debugfs attributes for Wilco EC |
| * |
| * Copyright 2019 Google LLC |
| * |
| * See Documentation/ABI/testing/debugfs-wilco-ec for usage. |
| */ |
| |
| #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 raw bytes will take up more space when represented as a hex string */ |
| #define FORMATTED_BUFFER_SIZE (EC_MAILBOX_DATA_SIZE * 4) |
| |
| struct wilco_ec_debugfs { |
| struct wilco_ec_device *ec; |
| struct dentry *dir; |
| size_t response_size; |
| u8 raw_data[EC_MAILBOX_DATA_SIZE]; |
| 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 byte of data */ |
| if (ret < 3) |
| return -EINVAL; |
| |
| msg.type = request_data[0] << 8 | request_data[1]; |
| msg.flags = 0; |
| msg.request_data = request_data + 2; |
| msg.request_size = ret - 2; |
| memset(debug_info->raw_data, 0, sizeof(debug_info->raw_data)); |
| msg.response_data = debug_info->raw_data; |
| msg.response_size = EC_MAILBOX_DATA_SIZE; |
| |
| 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, |
| sizeof(debug_info->formatted_data), |
| 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, |
| }; |
| |
| #define CMD_KB_CHROME 0x88 |
| #define SUB_CMD_H1_GPIO 0x0A |
| |
| struct h1_gpio_status_request { |
| u8 cmd; /* Always CMD_KB_CHROME */ |
| u8 reserved; |
| u8 sub_cmd; /* Always SUB_CMD_H1_GPIO */ |
| } __packed; |
| |
| struct hi_gpio_status_response { |
| u8 status; /* 0 if allowed */ |
| u8 val; /* BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL */ |
| } __packed; |
| |
| static int h1_gpio_get(void *arg, u64 *val) |
| { |
| struct wilco_ec_device *ec = arg; |
| struct h1_gpio_status_request rq; |
| struct hi_gpio_status_response rs; |
| struct wilco_ec_message msg; |
| int ret; |
| |
| memset(&rq, 0, sizeof(rq)); |
| rq.cmd = CMD_KB_CHROME; |
| rq.sub_cmd = SUB_CMD_H1_GPIO; |
| |
| memset(&msg, 0, sizeof(msg)); |
| msg.type = WILCO_EC_MSG_LEGACY; |
| msg.request_data = &rq; |
| msg.request_size = sizeof(rq); |
| msg.response_data = &rs; |
| msg.response_size = sizeof(rs); |
| ret = wilco_ec_mailbox(ec, &msg); |
| if (ret < 0) |
| return ret; |
| if (rs.status) |
| return -EIO; |
| |
| *val = rs.val; |
| |
| return 0; |
| } |
| |
| DEFINE_DEBUGFS_ATTRIBUTE(fops_h1_gpio, h1_gpio_get, NULL, "0x%02llx\n"); |
| |
| /** |
| * 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); |
| debugfs_create_file("h1_gpio", 0444, debug_info->dir, ec, |
| &fops_h1_gpio); |
| |
| 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"); |