drivers/s390/cio/ccwreq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Handling of internal CCW device requests.
   4  *
   5  *    Copyright IBM Corp. 2009, 2011
   6  *    Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
   7  */
   8
   9 #define KMSG_COMPONENT "cio"
  10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  11
  12 #include <linux/types.h>
  13 #include <linux/err.h>
  14 #include <asm/ccwdev.h>
  15 #include <asm/cio.h>
  16
  17 #include "io_sch.h"
  18 #include "cio.h"
  19 #include "device.h"
  20 #include "cio_debug.h"
  21
  22 /**
  23  * lpm_adjust - adjust path mask
  24  * @lpm: path mask to adjust
  25  * @mask: mask of available paths
  26  *
  27  * Shift @lpm right until @lpm and @mask have at least one bit in common or
  28  * until @lpm is zero. Return the resulting lpm.
  29  */
  30 int lpm_adjust(int lpm, int mask)
  31 {
  32         while (lpm && ((lpm & mask) == 0))
  33                 lpm >>= 1;
  34         return lpm;
  35 }
  36
  37 /*
  38  * Adjust path mask to use next path and reset retry count. Return resulting
  39  * path mask.
  40  */
  41 static u16 ccwreq_next_path(struct ccw_device *cdev)
  42 {
  43         struct ccw_request *req = &cdev->private->req;
  44
  45         if (!req->singlepath) {
  46                 req->mask = 0;
  47                 goto out;
  48         }
  49         req->retries    = req->maxretries;
  50         req->mask       = lpm_adjust(req->mask >> 1, req->lpm);
  51 out:
  52         return req->mask;
  53 }
  54
  55 /*
  56  * Clean up device state and report to callback.
  57  */
  58 static void ccwreq_stop(struct ccw_device *cdev, int rc)
  59 {
  60         struct ccw_request *req = &cdev->private->req;
  61
  62         if (req->done)
  63                 return;
  64         req->done = 1;
  65         ccw_device_set_timeout(cdev, 0);
  66         memset(&cdev->private->irb, 0, sizeof(struct irb));
  67         if (rc && rc != -ENODEV && req->drc)
  68                 rc = req->drc;
  69         req->callback(cdev, req->data, rc);
  70 }
  71
  72 /*
  73  * (Re-)Start the operation until retries and paths are exhausted.
  74  */
  75 static void ccwreq_do(struct ccw_device *cdev)
  76 {
  77         struct ccw_request *req = &cdev->private->req;
  78         struct subchannel *sch = to_subchannel(cdev->dev.parent);
  79         struct ccw1 *cp = req->cp;
  80         int rc = -EACCES;
  81
  82         while (req->mask) {
  83                 if (req->retries-- == 0) {
  84                         /* Retries exhausted, try next path. */
  85                         ccwreq_next_path(cdev);
  86                         continue;
  87                 }
  88                 /* Perform start function. */
  89                 memset(&cdev->private->irb, 0, sizeof(struct irb));
  90                 rc = cio_start(sch, cp, (u8) req->mask);
  91                 if (rc == 0) {
  92                         /* I/O started successfully. */
  93                         ccw_device_set_timeout(cdev, req->timeout);
  94                         return;
  95                 }
  96                 if (rc == -ENODEV) {
  97                         /* Permanent device error. */
  98                         break;
  99                 }
 100                 if (rc == -EACCES) {
 101                         /* Permant path error. */
 102                         ccwreq_next_path(cdev);
 103                         continue;
 104                 }
 105                 /* Temporary improper status. */
 106                 rc = cio_clear(sch);
 107                 if (rc)
 108                         break;
 109                 return;
 110         }
 111         ccwreq_stop(cdev, rc);
 112 }
 113
 114 /**
 115  * ccw_request_start - perform I/O request
 116  * @cdev: ccw device
 117  *
 118  * Perform the I/O request specified by cdev->req.
 119  */
 120 void ccw_request_start(struct ccw_device *cdev)
 121 {
 122         struct ccw_request *req = &cdev->private->req;
 123
 124         if (req->singlepath) {
 125                 /* Try all paths twice to counter link flapping. */
 126                 req->mask = 0x8080;
 127         } else
 128                 req->mask = req->lpm;
 129
 130         req->retries    = req->maxretries;
 131         req->mask       = lpm_adjust(req->mask, req->lpm);
 132         req->drc        = 0;
 133         req->done       = 0;
 134         req->cancel     = 0;
 135         if (!req->mask)
 136                 goto out_nopath;
 137         ccwreq_do(cdev);
 138         return;
 139
 140 out_nopath:
 141         ccwreq_stop(cdev, -EACCES);
 142 }
 143
 144 /**
 145  * ccw_request_cancel - cancel running I/O request
 146  * @cdev: ccw device
 147  *
 148  * Cancel the I/O request specified by cdev->req. Return non-zero if request
 149  * has already finished, zero otherwise.
 150  */
 151 int ccw_request_cancel(struct ccw_device *cdev)
 152 {
 153         struct subchannel *sch = to_subchannel(cdev->dev.parent);
 154         struct ccw_request *req = &cdev->private->req;
 155         int rc;
 156
 157         if (req->done)
 158                 return 1;
 159         req->cancel = 1;
 160         rc = cio_clear(sch);
 161         if (rc)
 162                 ccwreq_stop(cdev, rc);
 163         return 0;
 164 }
 165
 166 /*
 167  * Return the status of the internal I/O started on the specified ccw device.
 168  * Perform BASIC SENSE if required.
 169  */
 170 static enum io_status ccwreq_status(struct ccw_device *cdev, struct irb *lcirb)
 171 {
 172         struct irb *irb = &cdev->private->irb;
 173         struct cmd_scsw *scsw = &irb->scsw.cmd;
 174         enum uc_todo todo;
 175
 176         /* Perform BASIC SENSE if needed. */
 177         if (ccw_device_accumulate_and_sense(cdev, lcirb))
 178                 return IO_RUNNING;
 179         /* Check for halt/clear interrupt. */
 180         if (scsw->fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC))
 181                 return IO_KILLED;
 182         /* Check for path error. */
 183         if (scsw->cc == 3 || scsw->pno)
 184                 return IO_PATH_ERROR;
 185         /* Handle BASIC SENSE data. */
 186         if (irb->esw.esw0.erw.cons) {
 187                 CIO_TRACE_EVENT(2, "sensedata");
 188                 CIO_HEX_EVENT(2, &cdev->private->dev_id,
 189                               sizeof(struct ccw_dev_id));
 190                 CIO_HEX_EVENT(2, &cdev->private->irb.ecw, SENSE_MAX_COUNT);
 191                 /* Check for command reject. */
 192                 if (irb->ecw[0] & SNS0_CMD_REJECT)
 193                         return IO_REJECTED;
 194                 /* Ask the driver what to do */
 195                 if (cdev->drv && cdev->drv->uc_handler) {
 196                         todo = cdev->drv->uc_handler(cdev, lcirb);
 197                         CIO_TRACE_EVENT(2, "uc_response");
 198                         CIO_HEX_EVENT(2, &todo, sizeof(todo));
 199                         switch (todo) {
 200                         case UC_TODO_RETRY:
 201                                 return IO_STATUS_ERROR;
 202                         case UC_TODO_RETRY_ON_NEW_PATH:
 203                                 return IO_PATH_ERROR;
 204                         case UC_TODO_STOP:
 205                                 return IO_REJECTED;
 206                         default:
 207                                 return IO_STATUS_ERROR;
 208                         }
 209                 }
 210                 /* Assume that unexpected SENSE data implies an error. */
 211                 return IO_STATUS_ERROR;
 212         }
 213         /* Check for channel errors. */
 214         if (scsw->cstat != 0)
 215                 return IO_STATUS_ERROR;
 216         /* Check for device errors. */
 217         if (scsw->dstat & ~(DEV_STAT_CHN_END | DEV_STAT_DEV_END))
 218                 return IO_STATUS_ERROR;
 219         /* Check for final state. */
 220         if (!(scsw->dstat & DEV_STAT_DEV_END))
 221                 return IO_RUNNING;
 222         /* Check for other improper status. */
 223         if (scsw->cc == 1 && (scsw->stctl & SCSW_STCTL_ALERT_STATUS))
 224                 return IO_STATUS_ERROR;
 225         return IO_DONE;
 226 }
 227
 228 /*
 229  * Log ccw request status.
 230  */
 231 static void ccwreq_log_status(struct ccw_device *cdev, enum io_status status)
 232 {
 233         struct ccw_request *req = &cdev->private->req;
 234         struct {
 235                 struct ccw_dev_id dev_id;
 236                 u16 retries;
 237                 u8 lpm;
 238                 u8 status;
 239         }  __attribute__ ((packed)) data;
 240         data.dev_id     = cdev->private->dev_id;
 241         data.retries    = req->retries;
 242         data.lpm        = (u8) req->mask;
 243         data.status     = (u8) status;
 244         CIO_TRACE_EVENT(2, "reqstat");
 245         CIO_HEX_EVENT(2, &data, sizeof(data));
 246 }
 247
 248 /**
 249  * ccw_request_handler - interrupt handler for I/O request procedure.
 250  * @cdev: ccw device
 251  *
 252  * Handle interrupt during I/O request procedure.
 253  */
 254 void ccw_request_handler(struct ccw_device *cdev)
 255 {
 256         struct irb *irb = this_cpu_ptr(&cio_irb);
 257         struct ccw_request *req = &cdev->private->req;
 258         enum io_status status;
 259         int rc = -EOPNOTSUPP;
 260
 261         /* Check status of I/O request. */
 262         status = ccwreq_status(cdev, irb);
 263         if (req->filter)
 264                 status = req->filter(cdev, req->data, irb, status);
 265         if (status != IO_RUNNING)
 266                 ccw_device_set_timeout(cdev, 0);
 267         if (status != IO_DONE && status != IO_RUNNING)
 268                 ccwreq_log_status(cdev, status);
 269         switch (status) {
 270         case IO_DONE:
 271                 break;
 272         case IO_RUNNING:
 273                 return;
 274         case IO_REJECTED:
 275                 goto err;
 276         case IO_PATH_ERROR:
 277                 goto out_next_path;
 278         case IO_STATUS_ERROR:
 279                 goto out_restart;
 280         case IO_KILLED:
 281                 /* Check if request was cancelled on purpose. */
 282                 if (req->cancel) {
 283                         rc = -EIO;
 284                         goto err;
 285                 }
 286                 goto out_restart;
 287         }
 288         /* Check back with request initiator. */
 289         if (!req->check)
 290                 goto out;
 291         switch (req->check(cdev, req->data)) {
 292         case 0:
 293                 break;
 294         case -EAGAIN:
 295                 goto out_restart;
 296         case -EACCES:
 297                 goto out_next_path;
 298         default:
 299                 goto err;
 300         }
 301 out:
 302         ccwreq_stop(cdev, 0);
 303         return;
 304
 305 out_next_path:
 306         /* Try next path and restart I/O. */
 307         if (!ccwreq_next_path(cdev)) {
 308                 rc = -EACCES;
 309                 goto err;
 310         }
 311 out_restart:
 312         /* Restart. */
 313         ccwreq_do(cdev);
 314         return;
 315 err:
 316         ccwreq_stop(cdev, rc);
 317 }
 318
 319
 320 /**
 321  * ccw_request_timeout - timeout handler for I/O request procedure
 322  * @cdev: ccw device
 323  *
 324  * Handle timeout during I/O request procedure.
 325  */
 326 void ccw_request_timeout(struct ccw_device *cdev)
 327 {
 328         struct subchannel *sch = to_subchannel(cdev->dev.parent);
 329         struct ccw_request *req = &cdev->private->req;
 330         int rc = -ENODEV, chp;
 331
 332         if (cio_update_schib(sch))
 333                 goto err;
 334
 335         for (chp = 0; chp < 8; chp++) {
 336                 if ((0x80 >> chp) & sch->schib.pmcw.lpum)
 337                         pr_warn("%s: No interrupt was received within %lus (CS=%02x, DS=%02x, CHPID=%x.%02x)\n",
 338                                 dev_name(&cdev->dev), req->timeout / HZ,
 339                                 scsw_cstat(&sch->schib.scsw),
 340                                 scsw_dstat(&sch->schib.scsw),
 341                                 sch->schid.cssid,
 342                                 sch->schib.pmcw.chpid[chp]);
 343         }
 344
 345         if (!ccwreq_next_path(cdev)) {
 346                 /* set the final return code for this request */
 347                 req->drc = -ETIME;
 348         }
 349         rc = cio_clear(sch);
 350         if (rc)
 351                 goto err;
 352         return;
 353
 354 err:
 355         ccwreq_stop(cdev, rc);
 356 }
 357
 358 /**
 359  * ccw_request_notoper - notoper handler for I/O request procedure
 360  * @cdev: ccw device
 361  *
 362  * Handle notoper during I/O request procedure.
 363  */
 364 void ccw_request_notoper(struct ccw_device *cdev)
 365 {
 366         ccwreq_stop(cdev, -ENODEV);
 367 }