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368 lines
8.4 KiB
368 lines
8.4 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Handling of internal CCW device requests. |
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* |
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* Copyright IBM Corp. 2009, 2011 |
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* Author(s): Peter Oberparleiter <[email protected]> |
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*/ |
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#define KMSG_COMPONENT "cio" |
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
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#include <linux/types.h> |
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#include <linux/err.h> |
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#include <asm/ccwdev.h> |
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#include <asm/cio.h> |
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#include "io_sch.h" |
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#include "cio.h" |
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#include "device.h" |
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#include "cio_debug.h" |
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/** |
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* lpm_adjust - adjust path mask |
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* @lpm: path mask to adjust |
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* @mask: mask of available paths |
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* |
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* Shift @lpm right until @lpm and @mask have at least one bit in common or |
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* until @lpm is zero. Return the resulting lpm. |
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*/ |
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int lpm_adjust(int lpm, int mask) |
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{ |
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while (lpm && ((lpm & mask) == 0)) |
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lpm >>= 1; |
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return lpm; |
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} |
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/* |
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* Adjust path mask to use next path and reset retry count. Return resulting |
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* path mask. |
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*/ |
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static u16 ccwreq_next_path(struct ccw_device *cdev) |
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{ |
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struct ccw_request *req = &cdev->private->req; |
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if (!req->singlepath) { |
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req->mask = 0; |
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goto out; |
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} |
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req->retries = req->maxretries; |
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req->mask = lpm_adjust(req->mask >> 1, req->lpm); |
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out: |
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return req->mask; |
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} |
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/* |
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* Clean up device state and report to callback. |
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*/ |
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static void ccwreq_stop(struct ccw_device *cdev, int rc) |
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{ |
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struct ccw_request *req = &cdev->private->req; |
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if (req->done) |
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return; |
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req->done = 1; |
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ccw_device_set_timeout(cdev, 0); |
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memset(&cdev->private->dma_area->irb, 0, sizeof(struct irb)); |
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if (rc && rc != -ENODEV && req->drc) |
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rc = req->drc; |
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req->callback(cdev, req->data, rc); |
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} |
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/* |
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* (Re-)Start the operation until retries and paths are exhausted. |
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*/ |
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static void ccwreq_do(struct ccw_device *cdev) |
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{ |
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struct ccw_request *req = &cdev->private->req; |
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struct subchannel *sch = to_subchannel(cdev->dev.parent); |
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struct ccw1 *cp = req->cp; |
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int rc = -EACCES; |
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while (req->mask) { |
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if (req->retries-- == 0) { |
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/* Retries exhausted, try next path. */ |
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ccwreq_next_path(cdev); |
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continue; |
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} |
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/* Perform start function. */ |
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memset(&cdev->private->dma_area->irb, 0, sizeof(struct irb)); |
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rc = cio_start(sch, cp, (u8) req->mask); |
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if (rc == 0) { |
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/* I/O started successfully. */ |
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ccw_device_set_timeout(cdev, req->timeout); |
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return; |
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} |
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if (rc == -ENODEV) { |
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/* Permanent device error. */ |
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break; |
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} |
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if (rc == -EACCES) { |
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/* Permant path error. */ |
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ccwreq_next_path(cdev); |
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continue; |
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} |
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/* Temporary improper status. */ |
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rc = cio_clear(sch); |
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if (rc) |
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break; |
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return; |
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} |
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ccwreq_stop(cdev, rc); |
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} |
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/** |
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* ccw_request_start - perform I/O request |
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* @cdev: ccw device |
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* |
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* Perform the I/O request specified by cdev->req. |
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*/ |
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void ccw_request_start(struct ccw_device *cdev) |
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{ |
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struct ccw_request *req = &cdev->private->req; |
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if (req->singlepath) { |
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/* Try all paths twice to counter link flapping. */ |
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req->mask = 0x8080; |
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} else |
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req->mask = req->lpm; |
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req->retries = req->maxretries; |
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req->mask = lpm_adjust(req->mask, req->lpm); |
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req->drc = 0; |
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req->done = 0; |
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req->cancel = 0; |
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if (!req->mask) |
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goto out_nopath; |
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ccwreq_do(cdev); |
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return; |
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out_nopath: |
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ccwreq_stop(cdev, -EACCES); |
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} |
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/** |
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* ccw_request_cancel - cancel running I/O request |
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* @cdev: ccw device |
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* |
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* Cancel the I/O request specified by cdev->req. Return non-zero if request |
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* has already finished, zero otherwise. |
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*/ |
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int ccw_request_cancel(struct ccw_device *cdev) |
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{ |
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struct subchannel *sch = to_subchannel(cdev->dev.parent); |
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struct ccw_request *req = &cdev->private->req; |
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int rc; |
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if (req->done) |
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return 1; |
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req->cancel = 1; |
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rc = cio_clear(sch); |
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if (rc) |
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ccwreq_stop(cdev, rc); |
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return 0; |
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} |
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/* |
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* Return the status of the internal I/O started on the specified ccw device. |
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* Perform BASIC SENSE if required. |
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*/ |
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static enum io_status ccwreq_status(struct ccw_device *cdev, struct irb *lcirb) |
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{ |
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struct irb *irb = &cdev->private->dma_area->irb; |
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struct cmd_scsw *scsw = &irb->scsw.cmd; |
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enum uc_todo todo; |
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/* Perform BASIC SENSE if needed. */ |
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if (ccw_device_accumulate_and_sense(cdev, lcirb)) |
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return IO_RUNNING; |
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/* Check for halt/clear interrupt. */ |
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if (scsw->fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC)) |
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return IO_KILLED; |
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/* Check for path error. */ |
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if (scsw->cc == 3 || scsw->pno) |
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return IO_PATH_ERROR; |
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/* Handle BASIC SENSE data. */ |
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if (irb->esw.esw0.erw.cons) { |
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CIO_TRACE_EVENT(2, "sensedata"); |
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CIO_HEX_EVENT(2, &cdev->private->dev_id, |
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sizeof(struct ccw_dev_id)); |
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CIO_HEX_EVENT(2, &cdev->private->dma_area->irb.ecw, |
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SENSE_MAX_COUNT); |
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/* Check for command reject. */ |
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if (irb->ecw[0] & SNS0_CMD_REJECT) |
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return IO_REJECTED; |
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/* Ask the driver what to do */ |
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if (cdev->drv && cdev->drv->uc_handler) { |
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todo = cdev->drv->uc_handler(cdev, lcirb); |
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CIO_TRACE_EVENT(2, "uc_response"); |
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CIO_HEX_EVENT(2, &todo, sizeof(todo)); |
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switch (todo) { |
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case UC_TODO_RETRY: |
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return IO_STATUS_ERROR; |
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case UC_TODO_RETRY_ON_NEW_PATH: |
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return IO_PATH_ERROR; |
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case UC_TODO_STOP: |
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return IO_REJECTED; |
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default: |
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return IO_STATUS_ERROR; |
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} |
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} |
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/* Assume that unexpected SENSE data implies an error. */ |
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return IO_STATUS_ERROR; |
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} |
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/* Check for channel errors. */ |
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if (scsw->cstat != 0) |
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return IO_STATUS_ERROR; |
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/* Check for device errors. */ |
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if (scsw->dstat & ~(DEV_STAT_CHN_END | DEV_STAT_DEV_END)) |
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return IO_STATUS_ERROR; |
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/* Check for final state. */ |
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if (!(scsw->dstat & DEV_STAT_DEV_END)) |
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return IO_RUNNING; |
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/* Check for other improper status. */ |
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if (scsw->cc == 1 && (scsw->stctl & SCSW_STCTL_ALERT_STATUS)) |
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return IO_STATUS_ERROR; |
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return IO_DONE; |
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} |
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/* |
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* Log ccw request status. |
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*/ |
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static void ccwreq_log_status(struct ccw_device *cdev, enum io_status status) |
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{ |
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struct ccw_request *req = &cdev->private->req; |
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struct { |
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struct ccw_dev_id dev_id; |
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u16 retries; |
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u8 lpm; |
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u8 status; |
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} __attribute__ ((packed)) data; |
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data.dev_id = cdev->private->dev_id; |
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data.retries = req->retries; |
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data.lpm = (u8) req->mask; |
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data.status = (u8) status; |
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CIO_TRACE_EVENT(2, "reqstat"); |
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CIO_HEX_EVENT(2, &data, sizeof(data)); |
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} |
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/** |
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* ccw_request_handler - interrupt handler for I/O request procedure. |
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* @cdev: ccw device |
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* |
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* Handle interrupt during I/O request procedure. |
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*/ |
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void ccw_request_handler(struct ccw_device *cdev) |
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{ |
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struct irb *irb = this_cpu_ptr(&cio_irb); |
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struct ccw_request *req = &cdev->private->req; |
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enum io_status status; |
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int rc = -EOPNOTSUPP; |
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/* Check status of I/O request. */ |
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status = ccwreq_status(cdev, irb); |
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if (req->filter) |
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status = req->filter(cdev, req->data, irb, status); |
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if (status != IO_RUNNING) |
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ccw_device_set_timeout(cdev, 0); |
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if (status != IO_DONE && status != IO_RUNNING) |
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ccwreq_log_status(cdev, status); |
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switch (status) { |
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case IO_DONE: |
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break; |
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case IO_RUNNING: |
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return; |
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case IO_REJECTED: |
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goto err; |
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case IO_PATH_ERROR: |
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goto out_next_path; |
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case IO_STATUS_ERROR: |
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goto out_restart; |
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case IO_KILLED: |
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/* Check if request was cancelled on purpose. */ |
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if (req->cancel) { |
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rc = -EIO; |
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goto err; |
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} |
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goto out_restart; |
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} |
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/* Check back with request initiator. */ |
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if (!req->check) |
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goto out; |
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switch (req->check(cdev, req->data)) { |
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case 0: |
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break; |
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case -EAGAIN: |
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goto out_restart; |
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case -EACCES: |
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goto out_next_path; |
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default: |
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goto err; |
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} |
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out: |
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ccwreq_stop(cdev, 0); |
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return; |
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out_next_path: |
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/* Try next path and restart I/O. */ |
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if (!ccwreq_next_path(cdev)) { |
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rc = -EACCES; |
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goto err; |
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} |
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out_restart: |
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/* Restart. */ |
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ccwreq_do(cdev); |
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return; |
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err: |
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ccwreq_stop(cdev, rc); |
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} |
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/** |
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* ccw_request_timeout - timeout handler for I/O request procedure |
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* @cdev: ccw device |
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* |
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* Handle timeout during I/O request procedure. |
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*/ |
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void ccw_request_timeout(struct ccw_device *cdev) |
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{ |
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struct subchannel *sch = to_subchannel(cdev->dev.parent); |
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struct ccw_request *req = &cdev->private->req; |
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int rc = -ENODEV, chp; |
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if (cio_update_schib(sch)) |
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goto err; |
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for (chp = 0; chp < 8; chp++) { |
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if ((0x80 >> chp) & sch->schib.pmcw.lpum) |
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pr_warn("%s: No interrupt was received within %lus (CS=%02x, DS=%02x, CHPID=%x.%02x)\n", |
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dev_name(&cdev->dev), req->timeout / HZ, |
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scsw_cstat(&sch->schib.scsw), |
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scsw_dstat(&sch->schib.scsw), |
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sch->schid.cssid, |
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sch->schib.pmcw.chpid[chp]); |
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} |
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if (!ccwreq_next_path(cdev)) { |
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/* set the final return code for this request */ |
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req->drc = -ETIME; |
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} |
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rc = cio_clear(sch); |
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if (rc) |
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goto err; |
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return; |
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err: |
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ccwreq_stop(cdev, rc); |
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} |
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/** |
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* ccw_request_notoper - notoper handler for I/O request procedure |
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* @cdev: ccw device |
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* |
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* Handle notoper during I/O request procedure. |
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*/ |
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void ccw_request_notoper(struct ccw_device *cdev) |
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{ |
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ccwreq_stop(cdev, -ENODEV); |
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}
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