// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/ide.h>

int generic_ide_suspend(struct device *dev, pm_message_t mesg)
{
        ide_drive_t *drive = to_ide_device(dev);
        ide_drive_t *pair = ide_get_pair_dev(drive);
        ide_hwif_t *hwif = drive->hwif;
        struct request *rq;
        struct ide_pm_state rqpm;
        int ret;

        if (ide_port_acpi(hwif)) {
                /* call ACPI _GTM only once */
                if ((drive->dn & 1) == 0 || pair == NULL)
                        ide_acpi_get_timing(hwif);
        }

        memset(&rqpm, 0, sizeof(rqpm));
        rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
        ide_req(rq)->type = ATA_PRIV_PM_SUSPEND;
        rq->special = &rqpm;
        rqpm.pm_step = IDE_PM_START_SUSPEND;
        if (mesg.event == PM_EVENT_PRETHAW)
                mesg.event = PM_EVENT_FREEZE;
        rqpm.pm_state = mesg.event;

        blk_execute_rq(drive->queue, NULL, rq, 0);
        ret = scsi_req(rq)->result ? -EIO : 0;
        blk_put_request(rq);

        if (ret == 0 && ide_port_acpi(hwif)) {
                /* call ACPI _PS3 only after both devices are suspended */
                if ((drive->dn & 1) || pair == NULL)
                        ide_acpi_set_state(hwif, 0);
        }

        return ret;
}

static void ide_end_sync_rq(struct request *rq, blk_status_t error)
{
        complete(rq->end_io_data);
}

static int ide_pm_execute_rq(struct request *rq)
{
        struct request_queue *q = rq->q;
        DECLARE_COMPLETION_ONSTACK(wait);

        rq->end_io_data = &wait;
        rq->end_io = ide_end_sync_rq;

        spin_lock_irq(q->queue_lock);
        if (unlikely(blk_queue_dying(q))) {
                rq->rq_flags |= RQF_QUIET;
                scsi_req(rq)->result = -ENXIO;
                __blk_end_request_all(rq, BLK_STS_OK);
                spin_unlock_irq(q->queue_lock);
                return -ENXIO;
        }
        __elv_add_request(q, rq, ELEVATOR_INSERT_FRONT);
        __blk_run_queue_uncond(q);
        spin_unlock_irq(q->queue_lock);

        wait_for_completion_io(&wait);

        return scsi_req(rq)->result ? -EIO : 0;
}

int generic_ide_resume(struct device *dev)
{
        ide_drive_t *drive = to_ide_device(dev);
        ide_drive_t *pair = ide_get_pair_dev(drive);
        ide_hwif_t *hwif = drive->hwif;
        struct request *rq;
        struct ide_pm_state rqpm;
        int err;

        if (ide_port_acpi(hwif)) {
                /* call ACPI _PS0 / _STM only once */
                if ((drive->dn & 1) == 0 || pair == NULL) {
                        ide_acpi_set_state(hwif, 1);
                        ide_acpi_push_timing(hwif);
                }

                ide_acpi_exec_tfs(drive);
        }

        memset(&rqpm, 0, sizeof(rqpm));
        rq = blk_get_request_flags(drive->queue, REQ_OP_DRV_IN,
                                   BLK_MQ_REQ_PREEMPT);
        ide_req(rq)->type = ATA_PRIV_PM_RESUME;
        rq->special = &rqpm;
        rqpm.pm_step = IDE_PM_START_RESUME;
        rqpm.pm_state = PM_EVENT_ON;

        err = ide_pm_execute_rq(rq);
        blk_put_request(rq);

        if (err == 0 && dev->driver) {
                struct ide_driver *drv = to_ide_driver(dev->driver);

                if (drv->resume)
                        drv->resume(drive);
        }

        return err;
}

void ide_complete_power_step(ide_drive_t *drive, struct request *rq)
{
        struct ide_pm_state *pm = rq->special;

#ifdef DEBUG_PM
        printk(KERN_INFO "%s: complete_power_step(step: %d)\n",
                drive->name, pm->pm_step);
#endif
        if (drive->media != ide_disk)
                return;

        switch (pm->pm_step) {
        case IDE_PM_FLUSH_CACHE:        /* Suspend step 1 (flush cache) */
                if (pm->pm_state == PM_EVENT_FREEZE)
                        pm->pm_step = IDE_PM_COMPLETED;
                else
                        pm->pm_step = IDE_PM_STANDBY;
                break;
        case IDE_PM_STANDBY:            /* Suspend step 2 (standby) */
                pm->pm_step = IDE_PM_COMPLETED;
                break;
        case IDE_PM_RESTORE_PIO:        /* Resume step 1 (restore PIO) */
                pm->pm_step = IDE_PM_IDLE;
                break;
        case IDE_PM_IDLE:               /* Resume step 2 (idle)*/
                pm->pm_step = IDE_PM_RESTORE_DMA;
                break;
        }
}

ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
{
        struct ide_pm_state *pm = rq->special;
        struct ide_cmd cmd = { };

        switch (pm->pm_step) {
        case IDE_PM_FLUSH_CACHE:        /* Suspend step 1 (flush cache) */
                if (drive->media != ide_disk)
                        break;
                /* Not supported? Switch to next step now. */
                if (ata_id_flush_enabled(drive->id) == 0 ||
                    (drive->dev_flags & IDE_DFLAG_WCACHE) == 0) {
                        ide_complete_power_step(drive, rq);
                        return ide_stopped;
                }
                if (ata_id_flush_ext_enabled(drive->id))
                        cmd.tf.command = ATA_CMD_FLUSH_EXT;
                else
                        cmd.tf.command = ATA_CMD_FLUSH;
                goto out_do_tf;
        case IDE_PM_STANDBY:            /* Suspend step 2 (standby) */
                cmd.tf.command = ATA_CMD_STANDBYNOW1;
                goto out_do_tf;
        case IDE_PM_RESTORE_PIO:        /* Resume step 1 (restore PIO) */
                ide_set_max_pio(drive);
                /*
                 * skip IDE_PM_IDLE for ATAPI devices
                 */
                if (drive->media != ide_disk)
                        pm->pm_step = IDE_PM_RESTORE_DMA;
                else
                        ide_complete_power_step(drive, rq);
                return ide_stopped;
        case IDE_PM_IDLE:               /* Resume step 2 (idle) */
                cmd.tf.command = ATA_CMD_IDLEIMMEDIATE;
                goto out_do_tf;
        case IDE_PM_RESTORE_DMA:        /* Resume step 3 (restore DMA) */
                /*
                 * Right now, all we do is call ide_set_dma(drive),
                 * we could be smarter and check for current xfer_speed
                 * in struct drive etc...
                 */
                if (drive->hwif->dma_ops == NULL)
                        break;
                /*
                 * TODO: respect IDE_DFLAG_USING_DMA
                 */
                ide_set_dma(drive);
                break;
        }

        pm->pm_step = IDE_PM_COMPLETED;

        return ide_stopped;

out_do_tf:
        cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
        cmd.valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
        cmd.protocol = ATA_PROT_NODATA;

        return do_rw_taskfile(drive, &cmd);
}

/**
 *      ide_complete_pm_rq - end the current Power Management request
 *      @drive: target drive
 *      @rq: request
 *
 *      This function cleans up the current PM request and stops the queue
 *      if necessary.
 */
void ide_complete_pm_rq(ide_drive_t *drive, struct request *rq)
{
        struct request_queue *q = drive->queue;
        struct ide_pm_state *pm = rq->special;
        unsigned long flags;

        ide_complete_power_step(drive, rq);
        if (pm->pm_step != IDE_PM_COMPLETED)
                return;

#ifdef DEBUG_PM
        printk("%s: completing PM request, %s\n", drive->name,
               (ide_req(rq)->type == ATA_PRIV_PM_SUSPEND) ? "suspend" : "resume");
#endif
        spin_lock_irqsave(q->queue_lock, flags);
        if (ide_req(rq)->type == ATA_PRIV_PM_SUSPEND)
                blk_stop_queue(q);
        else
                drive->dev_flags &= ~IDE_DFLAG_BLOCKED;
        spin_unlock_irqrestore(q->queue_lock, flags);

        drive->hwif->rq = NULL;

        if (blk_end_request(rq, BLK_STS_OK, 0))
                BUG();
}

void ide_check_pm_state(ide_drive_t *drive, struct request *rq)
{
        struct ide_pm_state *pm = rq->special;

        if (blk_rq_is_private(rq) &&
            ide_req(rq)->type == ATA_PRIV_PM_SUSPEND &&
            pm->pm_step == IDE_PM_START_SUSPEND)
                /* Mark drive blocked when starting the suspend sequence. */
                drive->dev_flags |= IDE_DFLAG_BLOCKED;
        else if (blk_rq_is_private(rq) &&
                 ide_req(rq)->type == ATA_PRIV_PM_RESUME &&
                 pm->pm_step == IDE_PM_START_RESUME) {
                /*
                 * The first thing we do on wakeup is to wait for BSY bit to
                 * go away (with a looong timeout) as a drive on this hwif may
                 * just be POSTing itself.
                 * We do that before even selecting as the "other" device on
                 * the bus may be broken enough to walk on our toes at this
                 * point.
                 */
                ide_hwif_t *hwif = drive->hwif;
                const struct ide_tp_ops *tp_ops = hwif->tp_ops;
                struct request_queue *q = drive->queue;
                unsigned long flags;
                int rc;
#ifdef DEBUG_PM
                printk("%s: Wakeup request inited, waiting for !BSY...\n", drive->name);
#endif
                rc = ide_wait_not_busy(hwif, 35000);
                if (rc)
                        printk(KERN_WARNING "%s: bus not ready on wakeup\n", drive->name);
                tp_ops->dev_select(drive);
                tp_ops->write_devctl(hwif, ATA_DEVCTL_OBS);
                rc = ide_wait_not_busy(hwif, 100000);
                if (rc)
                        printk(KERN_WARNING "%s: drive not ready on wakeup\n", drive->name);

                spin_lock_irqsave(q->queue_lock, flags);
                blk_start_queue(q);
                spin_unlock_irqrestore(q->queue_lock, flags);
        }
}