blob: a812788a0bdcc2402d012fab056f3851dbc3373b [file] [log] [blame]
// 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
#define SUB_CMD_TEST_EVENT 0x0B
struct ec_request {
u8 cmd; /* Always CMD_KB_CHROME */
u8 reserved;
u8 sub_cmd;
} __packed;
struct ec_response {
u8 status; /* 0 if allowed */
u8 val;
} __packed;
static int send_ec_cmd(struct wilco_ec_device *ec, u8 sub_cmd, u8 *out_val)
{
struct ec_request rq;
struct ec_response rs;
struct wilco_ec_message msg;
int ret;
memset(&rq, 0, sizeof(rq));
rq.cmd = CMD_KB_CHROME;
rq.sub_cmd = sub_cmd;
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;
*out_val = rs.val;
return 0;
}
/**
* h1_gpio_get() - Gets h1 gpio status.
* @arg: The wilco EC device.
* @val: BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL
*/
static int h1_gpio_get(void *arg, u64 *val)
{
int ret;
ret = send_ec_cmd(arg, SUB_CMD_H1_GPIO, (u8 *)val);
if (ret == 0)
*val &= 0xFF;
return ret;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_h1_gpio, h1_gpio_get, NULL, "0x%02llx\n");
/**
* test_event_set() - Sends command to EC to cause an EC test event.
* @arg: The wilco EC device.
* @val: unused.
*/
static int test_event_set(void *arg, u64 val)
{
u8 ret;
return send_ec_cmd(arg, SUB_CMD_TEST_EVENT, &ret);
}
/* Format is unused since it is only required for get method which is NULL */
DEFINE_DEBUGFS_ATTRIBUTE(fops_test_event, NULL, test_event_set, "%llu\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);
debugfs_create_file("test_event", 0200, debug_info->dir, ec,
&fops_test_event);
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");