diff options
Diffstat (limited to 'kernel/drivers/s390/cio/ccwreq.c')
| -rw-r--r-- | kernel/drivers/s390/cio/ccwreq.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/kernel/drivers/s390/cio/ccwreq.c b/kernel/drivers/s390/cio/ccwreq.c new file mode 100644 index 000000000..79f59915f --- /dev/null +++ b/kernel/drivers/s390/cio/ccwreq.c @@ -0,0 +1,367 @@ +/* + * Handling of internal CCW device requests. + * + * Copyright IBM Corp. 2009, 2011 + * Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com> + */ + +#define KMSG_COMPONENT "cio" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#include <linux/types.h> +#include <linux/err.h> +#include <asm/ccwdev.h> +#include <asm/cio.h> + +#include "io_sch.h" +#include "cio.h" +#include "device.h" +#include "cio_debug.h" + +/** + * lpm_adjust - adjust path mask + * @lpm: path mask to adjust + * @mask: mask of available paths + * + * Shift @lpm right until @lpm and @mask have at least one bit in common or + * until @lpm is zero. Return the resulting lpm. + */ +int lpm_adjust(int lpm, int mask) +{ + while (lpm && ((lpm & mask) == 0)) + lpm >>= 1; + return lpm; +} + +/* + * Adjust path mask to use next path and reset retry count. Return resulting + * path mask. + */ +static u16 ccwreq_next_path(struct ccw_device *cdev) +{ + struct ccw_request *req = &cdev->private->req; + + if (!req->singlepath) { + req->mask = 0; + goto out; + } + req->retries = req->maxretries; + req->mask = lpm_adjust(req->mask >> 1, req->lpm); +out: + return req->mask; +} + +/* + * Clean up device state and report to callback. + */ +static void ccwreq_stop(struct ccw_device *cdev, int rc) +{ + struct ccw_request *req = &cdev->private->req; + + if (req->done) + return; + req->done = 1; + ccw_device_set_timeout(cdev, 0); + memset(&cdev->private->irb, 0, sizeof(struct irb)); + if (rc && rc != -ENODEV && req->drc) + rc = req->drc; + req->callback(cdev, req->data, rc); +} + +/* + * (Re-)Start the operation until retries and paths are exhausted. + */ +static void ccwreq_do(struct ccw_device *cdev) +{ + struct ccw_request *req = &cdev->private->req; + struct subchannel *sch = to_subchannel(cdev->dev.parent); + struct ccw1 *cp = req->cp; + int rc = -EACCES; + + while (req->mask) { + if (req->retries-- == 0) { + /* Retries exhausted, try next path. */ + ccwreq_next_path(cdev); + continue; + } + /* Perform start function. */ + memset(&cdev->private->irb, 0, sizeof(struct irb)); + rc = cio_start(sch, cp, (u8) req->mask); + if (rc == 0) { + /* I/O started successfully. */ + ccw_device_set_timeout(cdev, req->timeout); + return; + } + if (rc == -ENODEV) { + /* Permanent device error. */ + break; + } + if (rc == -EACCES) { + /* Permant path error. */ + ccwreq_next_path(cdev); + continue; + } + /* Temporary improper status. */ + rc = cio_clear(sch); + if (rc) + break; + return; + } + ccwreq_stop(cdev, rc); +} + +/** + * ccw_request_start - perform I/O request + * @cdev: ccw device + * + * Perform the I/O request specified by cdev->req. + */ +void ccw_request_start(struct ccw_device *cdev) +{ + struct ccw_request *req = &cdev->private->req; + + if (req->singlepath) { + /* Try all paths twice to counter link flapping. */ + req->mask = 0x8080; + } else + req->mask = req->lpm; + + req->retries = req->maxretries; + req->mask = lpm_adjust(req->mask, req->lpm); + req->drc = 0; + req->done = 0; + req->cancel = 0; + if (!req->mask) + goto out_nopath; + ccwreq_do(cdev); + return; + +out_nopath: + ccwreq_stop(cdev, -EACCES); +} + +/** + * ccw_request_cancel - cancel running I/O request + * @cdev: ccw device + * + * Cancel the I/O request specified by cdev->req. Return non-zero if request + * has already finished, zero otherwise. + */ +int ccw_request_cancel(struct ccw_device *cdev) +{ + struct subchannel *sch = to_subchannel(cdev->dev.parent); + struct ccw_request *req = &cdev->private->req; + int rc; + + if (req->done) + return 1; + req->cancel = 1; + rc = cio_clear(sch); + if (rc) + ccwreq_stop(cdev, rc); + return 0; +} + +/* + * Return the status of the internal I/O started on the specified ccw device. + * Perform BASIC SENSE if required. + */ +static enum io_status ccwreq_status(struct ccw_device *cdev, struct irb *lcirb) +{ + struct irb *irb = &cdev->private->irb; + struct cmd_scsw *scsw = &irb->scsw.cmd; + enum uc_todo todo; + + /* Perform BASIC SENSE if needed. */ + if (ccw_device_accumulate_and_sense(cdev, lcirb)) + return IO_RUNNING; + /* Check for halt/clear interrupt. */ + if (scsw->fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC)) + return IO_KILLED; + /* Check for path error. */ + if (scsw->cc == 3 || scsw->pno) + return IO_PATH_ERROR; + /* Handle BASIC SENSE data. */ + if (irb->esw.esw0.erw.cons) { + CIO_TRACE_EVENT(2, "sensedata"); + CIO_HEX_EVENT(2, &cdev->private->dev_id, + sizeof(struct ccw_dev_id)); + CIO_HEX_EVENT(2, &cdev->private->irb.ecw, SENSE_MAX_COUNT); + /* Check for command reject. */ + if (irb->ecw[0] & SNS0_CMD_REJECT) + return IO_REJECTED; + /* Ask the driver what to do */ + if (cdev->drv && cdev->drv->uc_handler) { + todo = cdev->drv->uc_handler(cdev, lcirb); + CIO_TRACE_EVENT(2, "uc_response"); + CIO_HEX_EVENT(2, &todo, sizeof(todo)); + switch (todo) { + case UC_TODO_RETRY: + return IO_STATUS_ERROR; + case UC_TODO_RETRY_ON_NEW_PATH: + return IO_PATH_ERROR; + case UC_TODO_STOP: + return IO_REJECTED; + default: + return IO_STATUS_ERROR; + } + } + /* Assume that unexpected SENSE data implies an error. */ + return IO_STATUS_ERROR; + } + /* Check for channel errors. */ + if (scsw->cstat != 0) + return IO_STATUS_ERROR; + /* Check for device errors. */ + if (scsw->dstat & ~(DEV_STAT_CHN_END | DEV_STAT_DEV_END)) + return IO_STATUS_ERROR; + /* Check for final state. */ + if (!(scsw->dstat & DEV_STAT_DEV_END)) + return IO_RUNNING; + /* Check for other improper status. */ + if (scsw->cc == 1 && (scsw->stctl & SCSW_STCTL_ALERT_STATUS)) + return IO_STATUS_ERROR; + return IO_DONE; +} + +/* + * Log ccw request status. + */ +static void ccwreq_log_status(struct ccw_device *cdev, enum io_status status) +{ + struct ccw_request *req = &cdev->private->req; + struct { + struct ccw_dev_id dev_id; + u16 retries; + u8 lpm; + u8 status; + } __attribute__ ((packed)) data; + data.dev_id = cdev->private->dev_id; + data.retries = req->retries; + data.lpm = (u8) req->mask; + data.status = (u8) status; + CIO_TRACE_EVENT(2, "reqstat"); + CIO_HEX_EVENT(2, &data, sizeof(data)); +} + +/** + * ccw_request_handler - interrupt handler for I/O request procedure. + * @cdev: ccw device + * + * Handle interrupt during I/O request procedure. + */ +void ccw_request_handler(struct ccw_device *cdev) +{ + struct irb *irb = this_cpu_ptr(&cio_irb); + struct ccw_request *req = &cdev->private->req; + enum io_status status; + int rc = -EOPNOTSUPP; + + /* Check status of I/O request. */ + status = ccwreq_status(cdev, irb); + if (req->filter) + status = req->filter(cdev, req->data, irb, status); + if (status != IO_RUNNING) + ccw_device_set_timeout(cdev, 0); + if (status != IO_DONE && status != IO_RUNNING) + ccwreq_log_status(cdev, status); + switch (status) { + case IO_DONE: + break; + case IO_RUNNING: + return; + case IO_REJECTED: + goto err; + case IO_PATH_ERROR: + goto out_next_path; + case IO_STATUS_ERROR: + goto out_restart; + case IO_KILLED: + /* Check if request was cancelled on purpose. */ + if (req->cancel) { + rc = -EIO; + goto err; + } + goto out_restart; + } + /* Check back with request initiator. */ + if (!req->check) + goto out; + switch (req->check(cdev, req->data)) { + case 0: + break; + case -EAGAIN: + goto out_restart; + case -EACCES: + goto out_next_path; + default: + goto err; + } +out: + ccwreq_stop(cdev, 0); + return; + +out_next_path: + /* Try next path and restart I/O. */ + if (!ccwreq_next_path(cdev)) { + rc = -EACCES; + goto err; + } +out_restart: + /* Restart. */ + ccwreq_do(cdev); + return; +err: + ccwreq_stop(cdev, rc); +} + + +/** + * ccw_request_timeout - timeout handler for I/O request procedure + * @cdev: ccw device + * + * Handle timeout during I/O request procedure. + */ +void ccw_request_timeout(struct ccw_device *cdev) +{ + struct subchannel *sch = to_subchannel(cdev->dev.parent); + struct ccw_request *req = &cdev->private->req; + int rc = -ENODEV, chp; + + if (cio_update_schib(sch)) + goto err; + + for (chp = 0; chp < 8; chp++) { + if ((0x80 >> chp) & sch->schib.pmcw.lpum) + pr_warning("%s: No interrupt was received within %lus " + "(CS=%02x, DS=%02x, CHPID=%x.%02x)\n", + dev_name(&cdev->dev), req->timeout / HZ, + scsw_cstat(&sch->schib.scsw), + scsw_dstat(&sch->schib.scsw), + sch->schid.cssid, + sch->schib.pmcw.chpid[chp]); + } + + if (!ccwreq_next_path(cdev)) { + /* set the final return code for this request */ + req->drc = -ETIME; + } + rc = cio_clear(sch); + if (rc) + goto err; + return; + +err: + ccwreq_stop(cdev, rc); +} + +/** + * ccw_request_notoper - notoper handler for I/O request procedure + * @cdev: ccw device + * + * Handle notoper during I/O request procedure. + */ +void ccw_request_notoper(struct ccw_device *cdev) +{ + ccwreq_stop(cdev, -ENODEV); +} |