1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * debugfs attributes for Wilco EC 4 * 5 * Copyright 2019 Google LLC 6 * 7 * See Documentation/ABI/testing/debugfs-wilco-ec for usage. 8 */ 9 10 #include <linux/ctype.h> 11 #include <linux/debugfs.h> 12 #include <linux/fs.h> 13 #include <linux/module.h> 14 #include <linux/platform_data/wilco-ec.h> 15 #include <linux/platform_device.h> 16 17 #define DRV_NAME "wilco-ec-debugfs" 18 19 /* The raw bytes will take up more space when represented as a hex string */ 20 #define FORMATTED_BUFFER_SIZE (EC_MAILBOX_DATA_SIZE * 4) 21 22 struct wilco_ec_debugfs { 23 struct wilco_ec_device *ec; 24 struct dentry *dir; 25 size_t response_size; 26 u8 raw_data[EC_MAILBOX_DATA_SIZE]; 27 u8 formatted_data[FORMATTED_BUFFER_SIZE]; 28 }; 29 static struct wilco_ec_debugfs *debug_info; 30 31 /** 32 * parse_hex_sentence() - Convert a ascii hex representation into byte array. 33 * @in: Input buffer of ascii. 34 * @isize: Length of input buffer. 35 * @out: Output buffer. 36 * @osize: Length of output buffer, e.g. max number of bytes to parse. 37 * 38 * An valid input is a series of ascii hexadecimal numbers, separated by spaces. 39 * An example valid input is 40 * " 00 f2 0 000076 6 0 ff" 41 * 42 * If an individual "word" within the hex sentence is longer than MAX_WORD_SIZE, 43 * then the sentence is illegal, and parsing will fail. 44 * 45 * Return: Number of bytes parsed, or negative error code on failure. 46 */ 47 static int parse_hex_sentence(const char *in, int isize, u8 *out, int osize) 48 { 49 int n_parsed = 0; 50 int word_start = 0; 51 int word_end; 52 int word_len; 53 /* Temp buffer for holding a "word" of chars that represents one byte */ 54 #define MAX_WORD_SIZE 16 55 char tmp[MAX_WORD_SIZE + 1]; 56 u8 byte; 57 58 while (word_start < isize && n_parsed < osize) { 59 /* Find the start of the next word */ 60 while (word_start < isize && isspace(in[word_start])) 61 word_start++; 62 /* reached the end of the input before next word? */ 63 if (word_start >= isize) 64 break; 65 66 /* Find the end of this word */ 67 word_end = word_start; 68 while (word_end < isize && !isspace(in[word_end])) 69 word_end++; 70 71 /* Copy to a tmp NULL terminated string */ 72 word_len = word_end - word_start; 73 if (word_len > MAX_WORD_SIZE) 74 return -EINVAL; 75 memcpy(tmp, in + word_start, word_len); 76 tmp[word_len] = '\0'; 77 78 /* 79 * Convert from hex string, place in output. If fails to parse, 80 * just return -EINVAL because specific error code is only 81 * relevant for this one word, returning it would be confusing. 82 */ 83 if (kstrtou8(tmp, 16, &byte)) 84 return -EINVAL; 85 out[n_parsed++] = byte; 86 87 word_start = word_end; 88 } 89 return n_parsed; 90 } 91 92 /* The message type takes up two bytes*/ 93 #define TYPE_AND_DATA_SIZE ((EC_MAILBOX_DATA_SIZE) + 2) 94 95 static ssize_t raw_write(struct file *file, const char __user *user_buf, 96 size_t count, loff_t *ppos) 97 { 98 char *buf = debug_info->formatted_data; 99 struct wilco_ec_message msg; 100 u8 request_data[TYPE_AND_DATA_SIZE]; 101 ssize_t kcount; 102 int ret; 103 104 if (count > FORMATTED_BUFFER_SIZE) 105 return -EINVAL; 106 107 kcount = simple_write_to_buffer(buf, FORMATTED_BUFFER_SIZE, ppos, 108 user_buf, count); 109 if (kcount < 0) 110 return kcount; 111 112 ret = parse_hex_sentence(buf, kcount, request_data, TYPE_AND_DATA_SIZE); 113 if (ret < 0) 114 return ret; 115 /* Need at least two bytes for message type and one byte of data */ 116 if (ret < 3) 117 return -EINVAL; 118 119 msg.type = request_data[0] << 8 | request_data[1]; 120 msg.flags = 0; 121 msg.request_data = request_data + 2; 122 msg.request_size = ret - 2; 123 memset(debug_info->raw_data, 0, sizeof(debug_info->raw_data)); 124 msg.response_data = debug_info->raw_data; 125 msg.response_size = EC_MAILBOX_DATA_SIZE; 126 127 ret = wilco_ec_mailbox(debug_info->ec, &msg); 128 if (ret < 0) 129 return ret; 130 debug_info->response_size = ret; 131 132 return count; 133 } 134 135 static ssize_t raw_read(struct file *file, char __user *user_buf, size_t count, 136 loff_t *ppos) 137 { 138 int fmt_len = 0; 139 140 if (debug_info->response_size) { 141 fmt_len = hex_dump_to_buffer(debug_info->raw_data, 142 debug_info->response_size, 143 16, 1, debug_info->formatted_data, 144 sizeof(debug_info->formatted_data), 145 true); 146 /* Only return response the first time it is read */ 147 debug_info->response_size = 0; 148 } 149 150 return simple_read_from_buffer(user_buf, count, ppos, 151 debug_info->formatted_data, fmt_len); 152 } 153 154 static const struct file_operations fops_raw = { 155 .owner = THIS_MODULE, 156 .read = raw_read, 157 .write = raw_write, 158 .llseek = no_llseek, 159 }; 160 161 #define CMD_KB_CHROME 0x88 162 #define SUB_CMD_H1_GPIO 0x0A 163 #define SUB_CMD_TEST_EVENT 0x0B 164 165 struct ec_request { 166 u8 cmd; /* Always CMD_KB_CHROME */ 167 u8 reserved; 168 u8 sub_cmd; 169 } __packed; 170 171 struct ec_response { 172 u8 status; /* 0 if allowed */ 173 u8 val; 174 } __packed; 175 176 static int send_ec_cmd(struct wilco_ec_device *ec, u8 sub_cmd, u8 *out_val) 177 { 178 struct ec_request rq; 179 struct ec_response rs; 180 struct wilco_ec_message msg; 181 int ret; 182 183 memset(&rq, 0, sizeof(rq)); 184 rq.cmd = CMD_KB_CHROME; 185 rq.sub_cmd = sub_cmd; 186 187 memset(&msg, 0, sizeof(msg)); 188 msg.type = WILCO_EC_MSG_LEGACY; 189 msg.request_data = &rq; 190 msg.request_size = sizeof(rq); 191 msg.response_data = &rs; 192 msg.response_size = sizeof(rs); 193 ret = wilco_ec_mailbox(ec, &msg); 194 if (ret < 0) 195 return ret; 196 if (rs.status) 197 return -EIO; 198 199 *out_val = rs.val; 200 201 return 0; 202 } 203 204 /** 205 * h1_gpio_get() - Gets h1 gpio status. 206 * @arg: The wilco EC device. 207 * @val: BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL 208 */ 209 static int h1_gpio_get(void *arg, u64 *val) 210 { 211 int ret; 212 213 ret = send_ec_cmd(arg, SUB_CMD_H1_GPIO, (u8 *)val); 214 if (ret == 0) 215 *val &= 0xFF; 216 return ret; 217 } 218 219 DEFINE_DEBUGFS_ATTRIBUTE(fops_h1_gpio, h1_gpio_get, NULL, "0x%02llx\n"); 220 221 /** 222 * test_event_set() - Sends command to EC to cause an EC test event. 223 * @arg: The wilco EC device. 224 * @val: unused. 225 */ 226 static int test_event_set(void *arg, u64 val) 227 { 228 u8 ret; 229 230 return send_ec_cmd(arg, SUB_CMD_TEST_EVENT, &ret); 231 } 232 233 /* Format is unused since it is only required for get method which is NULL */ 234 DEFINE_DEBUGFS_ATTRIBUTE(fops_test_event, NULL, test_event_set, "%llu\n"); 235 236 /** 237 * wilco_ec_debugfs_probe() - Create the debugfs node 238 * @pdev: The platform device, probably created in core.c 239 * 240 * Try to create a debugfs node. If it fails, then we don't want to change 241 * behavior at all, this is for debugging after all. Just fail silently. 242 * 243 * Return: 0 always. 244 */ 245 static int wilco_ec_debugfs_probe(struct platform_device *pdev) 246 { 247 struct wilco_ec_device *ec = dev_get_drvdata(pdev->dev.parent); 248 249 debug_info = devm_kzalloc(&pdev->dev, sizeof(*debug_info), GFP_KERNEL); 250 if (!debug_info) 251 return 0; 252 debug_info->ec = ec; 253 debug_info->dir = debugfs_create_dir("wilco_ec", NULL); 254 debugfs_create_file("raw", 0644, debug_info->dir, NULL, &fops_raw); 255 debugfs_create_file("h1_gpio", 0444, debug_info->dir, ec, 256 &fops_h1_gpio); 257 debugfs_create_file("test_event", 0200, debug_info->dir, ec, 258 &fops_test_event); 259 260 return 0; 261 } 262 263 static int wilco_ec_debugfs_remove(struct platform_device *pdev) 264 { 265 debugfs_remove_recursive(debug_info->dir); 266 267 return 0; 268 } 269 270 static struct platform_driver wilco_ec_debugfs_driver = { 271 .driver = { 272 .name = DRV_NAME, 273 }, 274 .probe = wilco_ec_debugfs_probe, 275 .remove = wilco_ec_debugfs_remove, 276 }; 277 278 module_platform_driver(wilco_ec_debugfs_driver); 279 280 MODULE_ALIAS("platform:" DRV_NAME); 281 MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>"); 282 MODULE_LICENSE("GPL v2"); 283 MODULE_DESCRIPTION("Wilco EC debugfs driver"); 284