// SPDX-License-Identifier: GPL-2.0
/*
* Handling of internal CCW device requests.
*
* Copyright IBM Corp. 2009, 2011
* Author(s): Peter Oberparleiter <[email protected]>
*/
#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->dma_area->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->dma_area->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->dma_area->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->dma_area->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_warn("%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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