linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 *  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. */