1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * OPAL PNOR flash MTD abstraction 4 * 5 * Copyright IBM 2015 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/errno.h> 11 #include <linux/of.h> 12 #include <linux/of_address.h> 13 #include <linux/platform_device.h> 14 #include <linux/string.h> 15 #include <linux/slab.h> 16 #include <linux/mtd/mtd.h> 17 #include <linux/mtd/partitions.h> 18 19 #include <linux/debugfs.h> 20 #include <linux/seq_file.h> 21 22 #include <asm/opal.h> 23 24 25 /* 26 * This driver creates the a Linux MTD abstraction for platform PNOR flash 27 * backed by OPAL calls 28 */ 29 30 struct powernv_flash { 31 struct mtd_info mtd; 32 u32 id; 33 }; 34 35 enum flash_op { 36 FLASH_OP_READ, 37 FLASH_OP_WRITE, 38 FLASH_OP_ERASE, 39 }; 40 41 /* 42 * Don't return -ERESTARTSYS if we can't get a token, the MTD core 43 * might have split up the call from userspace and called into the 44 * driver more than once, we'll already have done some amount of work. 45 */ 46 static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op, 47 loff_t offset, size_t len, size_t *retlen, u_char *buf) 48 { 49 struct powernv_flash *info = (struct powernv_flash *)mtd->priv; 50 struct device *dev = &mtd->dev; 51 int token; 52 struct opal_msg msg; 53 int rc; 54 55 dev_dbg(dev, "%s(op=%d, offset=0x%llx, len=%zu)\n", 56 __func__, op, offset, len); 57 58 token = opal_async_get_token_interruptible(); 59 if (token < 0) { 60 if (token != -ERESTARTSYS) 61 dev_err(dev, "Failed to get an async token\n"); 62 else 63 token = -EINTR; 64 return token; 65 } 66 67 switch (op) { 68 case FLASH_OP_READ: 69 rc = opal_flash_read(info->id, offset, __pa(buf), len, token); 70 break; 71 case FLASH_OP_WRITE: 72 rc = opal_flash_write(info->id, offset, __pa(buf), len, token); 73 break; 74 case FLASH_OP_ERASE: 75 rc = opal_flash_erase(info->id, offset, len, token); 76 break; 77 default: 78 WARN_ON_ONCE(1); 79 opal_async_release_token(token); 80 return -EIO; 81 } 82 83 if (rc == OPAL_ASYNC_COMPLETION) { 84 rc = opal_async_wait_response_interruptible(token, &msg); 85 if (rc) { 86 /* 87 * If we return the mtd core will free the 88 * buffer we've just passed to OPAL but OPAL 89 * will continue to read or write from that 90 * memory. 91 * It may be tempting to ultimately return 0 92 * if we're doing a read or a write since we 93 * are going to end up waiting until OPAL is 94 * done. However, because the MTD core sends 95 * us the userspace request in chunks, we need 96 * it to know we've been interrupted. 97 */ 98 rc = -EINTR; 99 if (opal_async_wait_response(token, &msg)) 100 dev_err(dev, "opal_async_wait_response() failed\n"); 101 goto out; 102 } 103 rc = opal_get_async_rc(msg); 104 } 105 106 /* 107 * OPAL does mutual exclusion on the flash, it will return 108 * OPAL_BUSY. 109 * During firmware updates by the service processor OPAL may 110 * be (temporarily) prevented from accessing the flash, in 111 * this case OPAL will also return OPAL_BUSY. 112 * Both cases aren't errors exactly but the flash could have 113 * changed, userspace should be informed. 114 */ 115 if (rc != OPAL_SUCCESS && rc != OPAL_BUSY) 116 dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n", 117 op, rc); 118 119 if (rc == OPAL_SUCCESS && retlen) 120 *retlen = len; 121 122 rc = opal_error_code(rc); 123 out: 124 opal_async_release_token(token); 125 return rc; 126 } 127 128 /** 129 * @mtd: the device 130 * @from: the offset to read from 131 * @len: the number of bytes to read 132 * @retlen: the number of bytes actually read 133 * @buf: the filled in buffer 134 * 135 * Returns 0 if read successful, or -ERRNO if an error occurred 136 */ 137 static int powernv_flash_read(struct mtd_info *mtd, loff_t from, size_t len, 138 size_t *retlen, u_char *buf) 139 { 140 return powernv_flash_async_op(mtd, FLASH_OP_READ, from, 141 len, retlen, buf); 142 } 143 144 /** 145 * @mtd: the device 146 * @to: the offset to write to 147 * @len: the number of bytes to write 148 * @retlen: the number of bytes actually written 149 * @buf: the buffer to get bytes from 150 * 151 * Returns 0 if write successful, -ERRNO if error occurred 152 */ 153 static int powernv_flash_write(struct mtd_info *mtd, loff_t to, size_t len, 154 size_t *retlen, const u_char *buf) 155 { 156 return powernv_flash_async_op(mtd, FLASH_OP_WRITE, to, 157 len, retlen, (u_char *)buf); 158 } 159 160 /** 161 * @mtd: the device 162 * @erase: the erase info 163 * Returns 0 if erase successful or -ERRNO if an error occurred 164 */ 165 static int powernv_flash_erase(struct mtd_info *mtd, struct erase_info *erase) 166 { 167 int rc; 168 169 rc = powernv_flash_async_op(mtd, FLASH_OP_ERASE, erase->addr, 170 erase->len, NULL, NULL); 171 if (rc) 172 erase->fail_addr = erase->addr; 173 174 return rc; 175 } 176 177 /** 178 * powernv_flash_set_driver_info - Fill the mtd_info structure and docg3 179 * structure @pdev: The platform device 180 * @mtd: The structure to fill 181 */ 182 static int powernv_flash_set_driver_info(struct device *dev, 183 struct mtd_info *mtd) 184 { 185 u64 size; 186 u32 erase_size; 187 int rc; 188 189 rc = of_property_read_u32(dev->of_node, "ibm,flash-block-size", 190 &erase_size); 191 if (rc) { 192 dev_err(dev, "couldn't get resource block size information\n"); 193 return rc; 194 } 195 196 rc = of_property_read_u64(dev->of_node, "reg", &size); 197 if (rc) { 198 dev_err(dev, "couldn't get resource size information\n"); 199 return rc; 200 } 201 202 /* 203 * Going to have to check what details I need to set and how to 204 * get them 205 */ 206 mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node); 207 mtd->type = MTD_NORFLASH; 208 mtd->flags = MTD_WRITEABLE; 209 mtd->size = size; 210 mtd->erasesize = erase_size; 211 mtd->writebufsize = mtd->writesize = 1; 212 mtd->owner = THIS_MODULE; 213 mtd->_erase = powernv_flash_erase; 214 mtd->_read = powernv_flash_read; 215 mtd->_write = powernv_flash_write; 216 mtd->dev.parent = dev; 217 mtd_set_of_node(mtd, dev->of_node); 218 return 0; 219 } 220 221 /** 222 * powernv_flash_probe 223 * @pdev: platform device 224 * 225 * Returns 0 on success, -ENOMEM, -ENXIO on error 226 */ 227 static int powernv_flash_probe(struct platform_device *pdev) 228 { 229 struct device *dev = &pdev->dev; 230 struct powernv_flash *data; 231 int ret; 232 233 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 234 if (!data) 235 return -ENOMEM; 236 237 data->mtd.priv = data; 238 239 ret = of_property_read_u32(dev->of_node, "ibm,opal-id", &(data->id)); 240 if (ret) { 241 dev_err(dev, "no device property 'ibm,opal-id'\n"); 242 return ret; 243 } 244 245 ret = powernv_flash_set_driver_info(dev, &data->mtd); 246 if (ret) 247 return ret; 248 249 dev_set_drvdata(dev, data); 250 251 /* 252 * The current flash that skiboot exposes is one contiguous flash chip 253 * with an ffs partition at the start, it should prove easier for users 254 * to deal with partitions or not as they see fit 255 */ 256 return mtd_device_register(&data->mtd, NULL, 0); 257 } 258 259 /** 260 * op_release - Release the driver 261 * @pdev: the platform device 262 * 263 * Returns 0 264 */ 265 static int powernv_flash_release(struct platform_device *pdev) 266 { 267 struct powernv_flash *data = dev_get_drvdata(&(pdev->dev)); 268 269 /* All resources should be freed automatically */ 270 return mtd_device_unregister(&(data->mtd)); 271 } 272 273 static const struct of_device_id powernv_flash_match[] = { 274 { .compatible = "ibm,opal-flash" }, 275 {} 276 }; 277 278 static struct platform_driver powernv_flash_driver = { 279 .driver = { 280 .name = "powernv_flash", 281 .of_match_table = powernv_flash_match, 282 }, 283 .remove = powernv_flash_release, 284 .probe = powernv_flash_probe, 285 }; 286 287 module_platform_driver(powernv_flash_driver); 288 289 MODULE_DEVICE_TABLE(of, powernv_flash_match); 290 MODULE_LICENSE("GPL"); 291 MODULE_AUTHOR("Cyril Bur <cyril.bur@au1.ibm.com>"); 292 MODULE_DESCRIPTION("MTD abstraction for OPAL flash"); 293