Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Handling of internal CCW device requests. |
| 3 | * |
| 4 | * Copyright IBM Corp. 2009 |
| 5 | * Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com> |
| 6 | */ |
| 7 | |
| 8 | #include <linux/types.h> |
| 9 | #include <linux/err.h> |
| 10 | #include <asm/ccwdev.h> |
| 11 | #include <asm/cio.h> |
| 12 | |
| 13 | #include "io_sch.h" |
| 14 | #include "cio.h" |
| 15 | #include "device.h" |
| 16 | #include "cio_debug.h" |
| 17 | |
| 18 | /** |
| 19 | * lpm_adjust - adjust path mask |
| 20 | * @lpm: path mask to adjust |
| 21 | * @mask: mask of available paths |
| 22 | * |
| 23 | * Shift @lpm right until @lpm and @mask have at least one bit in common or |
| 24 | * until @lpm is zero. Return the resulting lpm. |
| 25 | */ |
| 26 | int lpm_adjust(int lpm, int mask) |
| 27 | { |
| 28 | while (lpm && ((lpm & mask) == 0)) |
| 29 | lpm >>= 1; |
| 30 | return lpm; |
| 31 | } |
| 32 | |
| 33 | /* |
| 34 | * Adjust path mask to use next path and reset retry count. Return resulting |
| 35 | * path mask. |
| 36 | */ |
| 37 | static u16 ccwreq_next_path(struct ccw_device *cdev) |
| 38 | { |
| 39 | struct ccw_request *req = &cdev->private->req; |
| 40 | |
| 41 | req->retries = req->maxretries; |
| 42 | req->mask = lpm_adjust(req->mask >>= 1, req->lpm); |
| 43 | |
| 44 | return req->mask; |
| 45 | } |
| 46 | |
| 47 | /* |
| 48 | * Clean up device state and report to callback. |
| 49 | */ |
| 50 | static void ccwreq_stop(struct ccw_device *cdev, int rc) |
| 51 | { |
Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 52 | struct ccw_request *req = &cdev->private->req; |
| 53 | |
| 54 | if (req->done) |
| 55 | return; |
| 56 | req->done = 1; |
| 57 | ccw_device_set_timeout(cdev, 0); |
| 58 | memset(&cdev->private->irb, 0, sizeof(struct irb)); |
Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 59 | if (rc && rc != -ENODEV && req->drc) |
| 60 | rc = req->drc; |
| 61 | req->callback(cdev, req->data, rc); |
| 62 | } |
| 63 | |
| 64 | /* |
| 65 | * (Re-)Start the operation until retries and paths are exhausted. |
| 66 | */ |
| 67 | static void ccwreq_do(struct ccw_device *cdev) |
| 68 | { |
| 69 | struct ccw_request *req = &cdev->private->req; |
| 70 | struct subchannel *sch = to_subchannel(cdev->dev.parent); |
| 71 | struct ccw1 *cp = req->cp; |
| 72 | int rc = -EACCES; |
| 73 | |
| 74 | while (req->mask) { |
| 75 | if (req->retries-- == 0) { |
| 76 | /* Retries exhausted, try next path. */ |
| 77 | ccwreq_next_path(cdev); |
| 78 | continue; |
| 79 | } |
| 80 | /* Perform start function. */ |
Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 81 | memset(&cdev->private->irb, 0, sizeof(struct irb)); |
Peter Oberparleiter | de1b043 | 2009-12-07 12:51:40 +0100 | [diff] [blame] | 82 | rc = cio_start(sch, cp, (u8) req->mask); |
Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 83 | if (rc == 0) { |
| 84 | /* I/O started successfully. */ |
| 85 | ccw_device_set_timeout(cdev, req->timeout); |
| 86 | return; |
| 87 | } |
| 88 | if (rc == -ENODEV) { |
| 89 | /* Permanent device error. */ |
| 90 | break; |
| 91 | } |
| 92 | if (rc == -EACCES) { |
| 93 | /* Permant path error. */ |
| 94 | ccwreq_next_path(cdev); |
| 95 | continue; |
| 96 | } |
| 97 | /* Temporary improper status. */ |
| 98 | rc = cio_clear(sch); |
| 99 | if (rc) |
| 100 | break; |
| 101 | return; |
| 102 | } |
| 103 | ccwreq_stop(cdev, rc); |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * ccw_request_start - perform I/O request |
| 108 | * @cdev: ccw device |
| 109 | * |
| 110 | * Perform the I/O request specified by cdev->req. |
| 111 | */ |
| 112 | void ccw_request_start(struct ccw_device *cdev) |
| 113 | { |
| 114 | struct ccw_request *req = &cdev->private->req; |
| 115 | |
Peter Oberparleiter | de1b043 | 2009-12-07 12:51:40 +0100 | [diff] [blame] | 116 | /* Try all paths twice to counter link flapping. */ |
| 117 | req->mask = 0x8080; |
Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 118 | req->retries = req->maxretries; |
| 119 | req->mask = lpm_adjust(req->mask, req->lpm); |
| 120 | req->drc = 0; |
| 121 | req->done = 0; |
| 122 | req->cancel = 0; |
| 123 | if (!req->mask) |
| 124 | goto out_nopath; |
| 125 | ccwreq_do(cdev); |
| 126 | return; |
| 127 | |
| 128 | out_nopath: |
| 129 | ccwreq_stop(cdev, -EACCES); |
| 130 | } |
| 131 | |
| 132 | /** |
| 133 | * ccw_request_cancel - cancel running I/O request |
| 134 | * @cdev: ccw device |
| 135 | * |
| 136 | * Cancel the I/O request specified by cdev->req. Return non-zero if request |
| 137 | * has already finished, zero otherwise. |
| 138 | */ |
| 139 | int ccw_request_cancel(struct ccw_device *cdev) |
| 140 | { |
| 141 | struct subchannel *sch = to_subchannel(cdev->dev.parent); |
| 142 | struct ccw_request *req = &cdev->private->req; |
| 143 | int rc; |
| 144 | |
| 145 | if (req->done) |
| 146 | return 1; |
| 147 | req->cancel = 1; |
| 148 | rc = cio_clear(sch); |
| 149 | if (rc) |
| 150 | ccwreq_stop(cdev, rc); |
| 151 | return 0; |
| 152 | } |
| 153 | |
| 154 | /* |
| 155 | * Return the status of the internal I/O started on the specified ccw device. |
| 156 | * Perform BASIC SENSE if required. |
| 157 | */ |
| 158 | static enum io_status ccwreq_status(struct ccw_device *cdev, struct irb *lcirb) |
| 159 | { |
| 160 | struct irb *irb = &cdev->private->irb; |
| 161 | struct cmd_scsw *scsw = &irb->scsw.cmd; |
Michael Ernst | 094f210 | 2010-05-26 23:27:08 +0200 | [diff] [blame^] | 162 | enum uc_todo todo; |
Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 163 | |
| 164 | /* Perform BASIC SENSE if needed. */ |
| 165 | if (ccw_device_accumulate_and_sense(cdev, lcirb)) |
| 166 | return IO_RUNNING; |
| 167 | /* Check for halt/clear interrupt. */ |
| 168 | if (scsw->fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC)) |
| 169 | return IO_KILLED; |
| 170 | /* Check for path error. */ |
| 171 | if (scsw->cc == 3 || scsw->pno) |
| 172 | return IO_PATH_ERROR; |
| 173 | /* Handle BASIC SENSE data. */ |
| 174 | if (irb->esw.esw0.erw.cons) { |
| 175 | CIO_TRACE_EVENT(2, "sensedata"); |
| 176 | CIO_HEX_EVENT(2, &cdev->private->dev_id, |
| 177 | sizeof(struct ccw_dev_id)); |
| 178 | CIO_HEX_EVENT(2, &cdev->private->irb.ecw, SENSE_MAX_COUNT); |
| 179 | /* Check for command reject. */ |
| 180 | if (irb->ecw[0] & SNS0_CMD_REJECT) |
| 181 | return IO_REJECTED; |
Michael Ernst | 094f210 | 2010-05-26 23:27:08 +0200 | [diff] [blame^] | 182 | /* Ask the driver what to do */ |
| 183 | if (cdev->drv && cdev->drv->uc_handler) { |
| 184 | todo = cdev->drv->uc_handler(cdev, lcirb); |
| 185 | switch (todo) { |
| 186 | case UC_TODO_RETRY: |
| 187 | return IO_STATUS_ERROR; |
| 188 | case UC_TODO_RETRY_ON_NEW_PATH: |
| 189 | return IO_PATH_ERROR; |
| 190 | case UC_TODO_STOP: |
| 191 | return IO_REJECTED; |
| 192 | default: |
| 193 | return IO_STATUS_ERROR; |
| 194 | } |
| 195 | } |
Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 196 | /* Assume that unexpected SENSE data implies an error. */ |
| 197 | return IO_STATUS_ERROR; |
| 198 | } |
| 199 | /* Check for channel errors. */ |
| 200 | if (scsw->cstat != 0) |
| 201 | return IO_STATUS_ERROR; |
| 202 | /* Check for device errors. */ |
| 203 | if (scsw->dstat & ~(DEV_STAT_CHN_END | DEV_STAT_DEV_END)) |
| 204 | return IO_STATUS_ERROR; |
| 205 | /* Check for final state. */ |
| 206 | if (!(scsw->dstat & DEV_STAT_DEV_END)) |
| 207 | return IO_RUNNING; |
| 208 | /* Check for other improper status. */ |
| 209 | if (scsw->cc == 1 && (scsw->stctl & SCSW_STCTL_ALERT_STATUS)) |
| 210 | return IO_STATUS_ERROR; |
| 211 | return IO_DONE; |
| 212 | } |
| 213 | |
| 214 | /* |
| 215 | * Log ccw request status. |
| 216 | */ |
| 217 | static void ccwreq_log_status(struct ccw_device *cdev, enum io_status status) |
| 218 | { |
| 219 | struct ccw_request *req = &cdev->private->req; |
| 220 | struct { |
| 221 | struct ccw_dev_id dev_id; |
| 222 | u16 retries; |
| 223 | u8 lpm; |
| 224 | u8 status; |
| 225 | } __attribute__ ((packed)) data; |
| 226 | data.dev_id = cdev->private->dev_id; |
| 227 | data.retries = req->retries; |
Peter Oberparleiter | de1b043 | 2009-12-07 12:51:40 +0100 | [diff] [blame] | 228 | data.lpm = (u8) req->mask; |
Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 229 | data.status = (u8) status; |
| 230 | CIO_TRACE_EVENT(2, "reqstat"); |
| 231 | CIO_HEX_EVENT(2, &data, sizeof(data)); |
| 232 | } |
| 233 | |
| 234 | /** |
| 235 | * ccw_request_handler - interrupt handler for I/O request procedure. |
| 236 | * @cdev: ccw device |
| 237 | * |
| 238 | * Handle interrupt during I/O request procedure. |
| 239 | */ |
| 240 | void ccw_request_handler(struct ccw_device *cdev) |
| 241 | { |
Heiko Carstens | cbb870c | 2010-02-26 22:37:43 +0100 | [diff] [blame] | 242 | struct irb *irb = (struct irb *)&S390_lowcore.irb; |
Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 243 | struct ccw_request *req = &cdev->private->req; |
Peter Oberparleiter | e1f0fbd | 2009-12-07 12:51:25 +0100 | [diff] [blame] | 244 | enum io_status status; |
| 245 | int rc = -EOPNOTSUPP; |
| 246 | |
| 247 | /* Check status of I/O request. */ |
| 248 | status = ccwreq_status(cdev, irb); |
| 249 | if (req->filter) |
| 250 | status = req->filter(cdev, req->data, irb, status); |
| 251 | if (status != IO_RUNNING) |
| 252 | ccw_device_set_timeout(cdev, 0); |
| 253 | if (status != IO_DONE && status != IO_RUNNING) |
| 254 | ccwreq_log_status(cdev, status); |
| 255 | switch (status) { |
| 256 | case IO_DONE: |
| 257 | break; |
| 258 | case IO_RUNNING: |
| 259 | return; |
| 260 | case IO_REJECTED: |
| 261 | goto err; |
| 262 | case IO_PATH_ERROR: |
| 263 | goto out_next_path; |
| 264 | case IO_STATUS_ERROR: |
| 265 | goto out_restart; |
| 266 | case IO_KILLED: |
| 267 | /* Check if request was cancelled on purpose. */ |
| 268 | if (req->cancel) { |
| 269 | rc = -EIO; |
| 270 | goto err; |
| 271 | } |
| 272 | goto out_restart; |
| 273 | } |
| 274 | /* Check back with request initiator. */ |
| 275 | if (!req->check) |
| 276 | goto out; |
| 277 | switch (req->check(cdev, req->data)) { |
| 278 | case 0: |
| 279 | break; |
| 280 | case -EAGAIN: |
| 281 | goto out_restart; |
| 282 | case -EACCES: |
| 283 | goto out_next_path; |
| 284 | default: |
| 285 | goto err; |
| 286 | } |
| 287 | out: |
| 288 | ccwreq_stop(cdev, 0); |
| 289 | return; |
| 290 | |
| 291 | out_next_path: |
| 292 | /* Try next path and restart I/O. */ |
| 293 | if (!ccwreq_next_path(cdev)) { |
| 294 | rc = -EACCES; |
| 295 | goto err; |
| 296 | } |
| 297 | out_restart: |
| 298 | /* Restart. */ |
| 299 | ccwreq_do(cdev); |
| 300 | return; |
| 301 | err: |
| 302 | ccwreq_stop(cdev, rc); |
| 303 | } |
| 304 | |
| 305 | |
| 306 | /** |
| 307 | * ccw_request_timeout - timeout handler for I/O request procedure |
| 308 | * @cdev: ccw device |
| 309 | * |
| 310 | * Handle timeout during I/O request procedure. |
| 311 | */ |
| 312 | void ccw_request_timeout(struct ccw_device *cdev) |
| 313 | { |
| 314 | struct subchannel *sch = to_subchannel(cdev->dev.parent); |
| 315 | struct ccw_request *req = &cdev->private->req; |
| 316 | int rc; |
| 317 | |
| 318 | if (!ccwreq_next_path(cdev)) { |
| 319 | /* set the final return code for this request */ |
| 320 | req->drc = -ETIME; |
| 321 | } |
| 322 | rc = cio_clear(sch); |
| 323 | if (rc) |
| 324 | goto err; |
| 325 | return; |
| 326 | |
| 327 | err: |
| 328 | ccwreq_stop(cdev, rc); |
| 329 | } |
| 330 | |
| 331 | /** |
| 332 | * ccw_request_notoper - notoper handler for I/O request procedure |
| 333 | * @cdev: ccw device |
| 334 | * |
| 335 | * Handle timeout during I/O request procedure. |
| 336 | */ |
| 337 | void ccw_request_notoper(struct ccw_device *cdev) |
| 338 | { |
| 339 | ccwreq_stop(cdev, -ENODEV); |
| 340 | } |