--- /dev/null
+/*
+ * 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);
+}
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