1 /* 2 * OPAL PNOR flash MTD abstraction 3 * 4 * Copyright IBM 2015 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/errno.h> 20 #include <linux/of.h> 21 #include <linux/of_address.h> 22 #include <linux/platform_device.h> 23 #include <linux/string.h> 24 #include <linux/slab.h> 25 #include <linux/mtd/mtd.h> 26 #include <linux/mtd/partitions.h> 27 28 #include <linux/debugfs.h> 29 #include <linux/seq_file.h> 30 31 #include <asm/opal.h> 32 33 34 /* 35 * This driver creates the a Linux MTD abstraction for platform PNOR flash 36 * backed by OPAL calls 37 */ 38 39 struct powernv_flash { 40 struct mtd_info mtd; 41 u32 id; 42 }; 43 44 enum flash_op { 45 FLASH_OP_READ, 46 FLASH_OP_WRITE, 47 FLASH_OP_ERASE, 48 }; 49 50 /* 51 * Don't return -ERESTARTSYS if we can't get a token, the MTD core 52 * might have split up the call from userspace and called into the 53 * driver more than once, we'll already have done some amount of work. 54 */ 55 static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op, 56 loff_t offset, size_t len, size_t *retlen, u_char *buf) 57 { 58 struct powernv_flash *info = (struct powernv_flash *)mtd->priv; 59 struct device *dev = &mtd->dev; 60 int token; 61 struct opal_msg msg; 62 int rc; 63 64 dev_dbg(dev, "%s(op=%d, offset=0x%llx, len=%zu)\n", 65 __func__, op, offset, len); 66 67 token = opal_async_get_token_interruptible(); 68 if (token < 0) { 69 if (token != -ERESTARTSYS) 70 dev_err(dev, "Failed to get an async token\n"); 71 else 72 token = -EINTR; 73 return token; 74 } 75 76 switch (op) { 77 case FLASH_OP_READ: 78 rc = opal_flash_read(info->id, offset, __pa(buf), len, token); 79 break; 80 case FLASH_OP_WRITE: 81 rc = opal_flash_write(info->id, offset, __pa(buf), len, token); 82 break; 83 case FLASH_OP_ERASE: 84 rc = opal_flash_erase(info->id, offset, len, token); 85 break; 86 default: 87 WARN_ON_ONCE(1); 88 opal_async_release_token(token); 89 return -EIO; 90 } 91 92 if (rc == OPAL_ASYNC_COMPLETION) { 93 rc = opal_async_wait_response_interruptible(token, &msg); 94 if (rc) { 95 /* 96 * If we return the mtd core will free the 97 * buffer we've just passed to OPAL but OPAL 98 * will continue to read or write from that 99 * memory. 100 * It may be tempting to ultimately return 0 101 * if we're doing a read or a write since we 102 * are going to end up waiting until OPAL is 103 * done. However, because the MTD core sends 104 * us the userspace request in chunks, we need 105 * it to know we've been interrupted. 106 */ 107 rc = -EINTR; 108 if (opal_async_wait_response(token, &msg)) 109 dev_err(dev, "opal_async_wait_response() failed\n"); 110 goto out; 111 } 112 rc = opal_get_async_rc(msg); 113 } 114 115 /* 116 * OPAL does mutual exclusion on the flash, it will return 117 * OPAL_BUSY. 118 * During firmware updates by the service processor OPAL may 119 * be (temporarily) prevented from accessing the flash, in 120 * this case OPAL will also return OPAL_BUSY. 121 * Both cases aren't errors exactly but the flash could have 122 * changed, userspace should be informed. 123 */ 124 if (rc != OPAL_SUCCESS && rc != OPAL_BUSY) 125 dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n", 126 op, rc); 127 128 if (rc == OPAL_SUCCESS && retlen) 129 *retlen = len; 130 131 rc = opal_error_code(rc); 132 out: 133 opal_async_release_token(token); 134 return rc; 135 } 136 137 /** 138 * @mtd: the device 139 * @from: the offset to read from 140 * @len: the number of bytes to read 141 * @retlen: the number of bytes actually read 142 * @buf: the filled in buffer 143 * 144 * Returns 0 if read successful, or -ERRNO if an error occurred 145 */ 146 static int powernv_flash_read(struct mtd_info *mtd, loff_t from, size_t len, 147 size_t *retlen, u_char *buf) 148 { 149 return powernv_flash_async_op(mtd, FLASH_OP_READ, from, 150 len, retlen, buf); 151 } 152 153 /** 154 * @mtd: the device 155 * @to: the offset to write to 156 * @len: the number of bytes to write 157 * @retlen: the number of bytes actually written 158 * @buf: the buffer to get bytes from 159 * 160 * Returns 0 if write successful, -ERRNO if error occurred 161 */ 162 static int powernv_flash_write(struct mtd_info *mtd, loff_t to, size_t len, 163 size_t *retlen, const u_char *buf) 164 { 165 return powernv_flash_async_op(mtd, FLASH_OP_WRITE, to, 166 len, retlen, (u_char *)buf); 167 } 168 169 /** 170 * @mtd: the device 171 * @erase: the erase info 172 * Returns 0 if erase successful or -ERRNO if an error occurred 173 */ 174 static int powernv_flash_erase(struct mtd_info *mtd, struct erase_info *erase) 175 { 176 int rc; 177 178 rc = powernv_flash_async_op(mtd, FLASH_OP_ERASE, erase->addr, 179 erase->len, NULL, NULL); 180 if (rc) 181 erase->fail_addr = erase->addr; 182 183 return rc; 184 } 185 186 /** 187 * powernv_flash_set_driver_info - Fill the mtd_info structure and docg3 188 * structure @pdev: The platform device 189 * @mtd: The structure to fill 190 */ 191 static int powernv_flash_set_driver_info(struct device *dev, 192 struct mtd_info *mtd) 193 { 194 u64 size; 195 u32 erase_size; 196 int rc; 197 198 rc = of_property_read_u32(dev->of_node, "ibm,flash-block-size", 199 &erase_size); 200 if (rc) { 201 dev_err(dev, "couldn't get resource block size information\n"); 202 return rc; 203 } 204 205 rc = of_property_read_u64(dev->of_node, "reg", &size); 206 if (rc) { 207 dev_err(dev, "couldn't get resource size information\n"); 208 return rc; 209 } 210 211 /* 212 * Going to have to check what details I need to set and how to 213 * get them 214 */ 215 mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", dev->of_node); 216 mtd->type = MTD_NORFLASH; 217 mtd->flags = MTD_WRITEABLE; 218 mtd->size = size; 219 mtd->erasesize = erase_size; 220 mtd->writebufsize = mtd->writesize = 1; 221 mtd->owner = THIS_MODULE; 222 mtd->_erase = powernv_flash_erase; 223 mtd->_read = powernv_flash_read; 224 mtd->_write = powernv_flash_write; 225 mtd->dev.parent = dev; 226 mtd_set_of_node(mtd, dev->of_node); 227 return 0; 228 } 229 230 /** 231 * powernv_flash_probe 232 * @pdev: platform device 233 * 234 * Returns 0 on success, -ENOMEM, -ENXIO on error 235 */ 236 static int powernv_flash_probe(struct platform_device *pdev) 237 { 238 struct device *dev = &pdev->dev; 239 struct powernv_flash *data; 240 int ret; 241 242 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 243 if (!data) 244 return -ENOMEM; 245 246 data->mtd.priv = data; 247 248 ret = of_property_read_u32(dev->of_node, "ibm,opal-id", &(data->id)); 249 if (ret) { 250 dev_err(dev, "no device property 'ibm,opal-id'\n"); 251 return ret; 252 } 253 254 ret = powernv_flash_set_driver_info(dev, &data->mtd); 255 if (ret) 256 return ret; 257 258 dev_set_drvdata(dev, data); 259 260 /* 261 * The current flash that skiboot exposes is one contiguous flash chip 262 * with an ffs partition at the start, it should prove easier for users 263 * to deal with partitions or not as they see fit 264 */ 265 return mtd_device_register(&data->mtd, NULL, 0); 266 } 267 268 /** 269 * op_release - Release the driver 270 * @pdev: the platform device 271 * 272 * Returns 0 273 */ 274 static int powernv_flash_release(struct platform_device *pdev) 275 { 276 struct powernv_flash *data = dev_get_drvdata(&(pdev->dev)); 277 278 /* All resources should be freed automatically */ 279 return mtd_device_unregister(&(data->mtd)); 280 } 281 282 static const struct of_device_id powernv_flash_match[] = { 283 { .compatible = "ibm,opal-flash" }, 284 {} 285 }; 286 287 static struct platform_driver powernv_flash_driver = { 288 .driver = { 289 .name = "powernv_flash", 290 .of_match_table = powernv_flash_match, 291 }, 292 .remove = powernv_flash_release, 293 .probe = powernv_flash_probe, 294 }; 295 296 module_platform_driver(powernv_flash_driver); 297 298 MODULE_DEVICE_TABLE(of, powernv_flash_match); 299 MODULE_LICENSE("GPL"); 300 MODULE_AUTHOR("Cyril Bur <cyril.bur@au1.ibm.com>"); 301 MODULE_DESCRIPTION("MTD abstraction for OPAL flash"); 302