On Tue, July 09, 2013, Sujit Reddy Thumma wrote:
> As of now SCSI initiated error handling is broken because,
> the reset APIs don't try to bring back the device initialized and
> ready for further transfers.
>
> In case of timeouts, the scsi error handler takes care of handling aborts
> and resets. Improve the error handling in such scenario by resetting the
> device and host and re-initializing them in proper manner.
>
> Signed-off-by: Sujit Reddy Thumma <sthumma@xxxxxxxxxxxxxx>
> ---
> drivers/scsi/ufs/ufshcd.c | 467 +++++++++++++++++++++++++++++++++++++++------
> drivers/scsi/ufs/ufshcd.h | 2 +
> 2 files changed, 411 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 51ce096..b4c9910 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -69,9 +69,15 @@ enum {
>
> /* UFSHCD states */
> enum {
> - UFSHCD_STATE_OPERATIONAL,
> UFSHCD_STATE_RESET,
> UFSHCD_STATE_ERROR,
> + UFSHCD_STATE_OPERATIONAL,
> +};
> +
> +/* UFSHCD error handling flags */
> +enum {
> + UFSHCD_EH_HOST_RESET_PENDING = (1 << 0),
> + UFSHCD_EH_DEVICE_RESET_PENDING = (1 << 1),
> };
>
> /* Interrupt configuration options */
> @@ -87,6 +93,22 @@ enum {
> INT_AGGR_CONFIG,
> };
>
> +#define ufshcd_set_device_reset_pending(h) \
> + (h->eh_flags |= UFSHCD_EH_DEVICE_RESET_PENDING)
> +#define ufshcd_set_host_reset_pending(h) \
> + (h->eh_flags |= UFSHCD_EH_HOST_RESET_PENDING)
> +#define ufshcd_device_reset_pending(h) \
> + (h->eh_flags & UFSHCD_EH_DEVICE_RESET_PENDING)
> +#define ufshcd_host_reset_pending(h) \
> + (h->eh_flags & UFSHCD_EH_HOST_RESET_PENDING)
> +#define ufshcd_clear_device_reset_pending(h) \
> + (h->eh_flags &= ~UFSHCD_EH_DEVICE_RESET_PENDING)
> +#define ufshcd_clear_host_reset_pending(h) \
> + (h->eh_flags &= ~UFSHCD_EH_HOST_RESET_PENDING)
> +
> +static void ufshcd_tmc_handler(struct ufs_hba *hba);
> +static void ufshcd_async_scan(void *data, async_cookie_t cookie);
> +
> /*
> * ufshcd_wait_for_register - wait for register value to change
> * @hba - per-adapter interface
> @@ -851,9 +873,22 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
>
> tag = cmd->request->tag;
>
> - if (hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL) {
> + switch (hba->ufshcd_state) {
Lock is no needed for ufshcd_state?
> + case UFSHCD_STATE_OPERATIONAL:
> + break;
> + case UFSHCD_STATE_RESET:
> err = SCSI_MLQUEUE_HOST_BUSY;
> goto out;
> + case UFSHCD_STATE_ERROR:
> + set_host_byte(cmd, DID_ERROR);
> + cmd->scsi_done(cmd);
> + goto out;
> + default:
> + dev_WARN_ONCE(hba->dev, 1, "%s: invalid state %d\n",
> + __func__, hba->ufshcd_state);
> + set_host_byte(cmd, DID_BAD_TARGET);
> + cmd->scsi_done(cmd);
> + goto out;
> }
>
> /* acquire the tag to make sure device cmds don't use it */
> @@ -1573,8 +1608,6 @@ static int ufshcd_make_hba_operational(struct ufs_hba *hba)
> if (hba->ufshcd_state == UFSHCD_STATE_RESET)
> scsi_unblock_requests(hba->host);
>
> - hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
> -
> out:
> return err;
> }
> @@ -2273,6 +2306,106 @@ out:
> }
>
> /**
> + * ufshcd_utrl_is_rsr_enabled - check if run-stop register is enabled
> + * @hba: per-adapter instance
> + */
> +static bool ufshcd_utrl_is_rsr_enabled(struct ufs_hba *hba)
> +{
> + return ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_LIST_RUN_STOP) & 0x1;
> +}
> +
> +/**
> + * ufshcd_utmrl_is_rsr_enabled - check if run-stop register is enabled
> + * @hba: per-adapter instance
> + */
> +static bool ufshcd_utmrl_is_rsr_enabled(struct ufs_hba *hba)
> +{
> + return ufshcd_readl(hba, REG_UTP_TASK_REQ_LIST_RUN_STOP) & 0x1;
> +}
> +
> +/**
> + * ufshcd_complete_pending_tasks - complete outstanding tasks
> + * @hba: per adapter instance
> + *
> + * Abort in-progress task management commands and wakeup
> + * waiting threads.
> + *
> + * Returns non-zero error value when failed to clear all the commands.
> + */
> +static int ufshcd_complete_pending_tasks(struct ufs_hba *hba)
> +{
> + u32 reg;
> + int err = 0;
> + unsigned long flags;
> +
> + if (!hba->outstanding_tasks)
> + goto out;
> +
> + /* Clear UTMRL only when run-stop is enabled */
> + if (ufshcd_utmrl_is_rsr_enabled(hba))
> + ufshcd_writel(hba, ~hba->outstanding_tasks,
> + REG_UTP_TASK_REQ_LIST_CLEAR);
> +
> + /* poll for max. 1 sec to clear door bell register by h/w */
> + reg = ufshcd_wait_for_register(hba,
> + REG_UTP_TASK_REQ_DOOR_BELL,
> + hba->outstanding_tasks, 0, 1000, 1000);
> + if (reg & hba->outstanding_tasks)
> + err = -ETIMEDOUT;
> +
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + /* complete commands that were cleared out */
> + ufshcd_tmc_handler(hba);
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> +out:
> + if (err)
> + dev_err(hba->dev, "%s: failed, still pending = 0x%.8x\n",
> + __func__, reg);
> + return err;
> +}
> +
> +/**
> + * ufshcd_complete_pending_reqs - complete outstanding requests
> + * @hba: per adapter instance
> + *
> + * Abort in-progress transfer request commands and return them to SCSI.
> + *
> + * Returns non-zero error value when failed to clear all the commands.
> + */
> +static int ufshcd_complete_pending_reqs(struct ufs_hba *hba)
> +{
> + u32 reg;
> + int err = 0;
> + unsigned long flags;
> +
> + /* check if we completed all of them */
> + if (!hba->outstanding_reqs)
> + goto out;
> +
> + /* Clear UTRL only when run-stop is enabled */
> + if (ufshcd_utrl_is_rsr_enabled(hba))
> + ufshcd_writel(hba, ~hba->outstanding_reqs,
> + REG_UTP_TRANSFER_REQ_LIST_CLEAR);
> +
> + /* poll for max. 1 sec to clear door bell register by h/w */
> + reg = ufshcd_wait_for_register(hba,
> + REG_UTP_TRANSFER_REQ_DOOR_BELL,
> + hba->outstanding_reqs, 0, 1000, 1000);
> + if (reg & hba->outstanding_reqs)
> + err = -ETIMEDOUT;
> +
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + /* complete commands that were cleared out */
> + ufshcd_transfer_req_compl(hba);
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> +out:
> + if (err)
> + dev_err(hba->dev, "%s: failed, still pending = 0x%.8x\n",
> + __func__, reg);
> + return err;
> +}
> +
> +/**
> * ufshcd_fatal_err_handler - handle fatal errors
> * @hba: per adapter instance
> */
> @@ -2306,8 +2439,12 @@ static void ufshcd_err_handler(struct ufs_hba *hba)
> }
> return;
> fatal_eh:
> - hba->ufshcd_state = UFSHCD_STATE_ERROR;
> - schedule_work(&hba->feh_workq);
> + /* handle fatal errors only when link is functional */
> + if (hba->ufshcd_state == UFSHCD_STATE_OPERATIONAL) {
> + /* block commands at driver layer until error is handled */
> + hba->ufshcd_state = UFSHCD_STATE_ERROR;
Locking omitted for ufshcd_state?
> + schedule_work(&hba->feh_workq);
> + }
> }
>
> /**
> @@ -2475,75 +2612,155 @@ static int ufshcd_issue_tm_cmd(struct ufs_hba *hba, int lun_id, int task_id,
> }
>
> /**
> - * ufshcd_device_reset - reset device and abort all the pending commands
> - * @cmd: SCSI command pointer
> + * ufshcd_dme_end_point_reset - Notify device Unipro to perform reset
> + * @hba: per adapter instance
> *
> - * Returns SUCCESS/FAILED
> + * UIC_CMD_DME_END_PT_RST resets the UFS device completely, the UFS flags,
> + * attributes and descriptors are reset to default state. Callers are
> + * expected to initialize the whole device again after this.
> + *
> + * Returns zero on success, non-zero on failure
> */
> -static int ufshcd_device_reset(struct scsi_cmnd *cmd)
> +static int ufshcd_dme_end_point_reset(struct ufs_hba *hba)
> {
> - struct Scsi_Host *host;
> - struct ufs_hba *hba;
> - unsigned int tag;
> - u32 pos;
> - int err;
> - u8 resp;
> - struct ufshcd_lrb *lrbp;
> + struct uic_command uic_cmd = {0};
> + int ret;
>
> - host = cmd->device->host;
> - hba = shost_priv(host);
> - tag = cmd->request->tag;
> + uic_cmd.command = UIC_CMD_DME_END_PT_RST;
>
> - lrbp = &hba->lrb[tag];
> - err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,
> - UFS_LOGICAL_RESET, &resp);
> - if (err || resp != UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
> - err = FAILED;
> + ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
> + if (ret)
> + dev_err(hba->dev, "%s: error code %d\n", __func__, ret);
> +
> + return ret;
> +}
> +
> +/**
> + * ufshcd_dme_reset - Local UniPro reset
> + * @hba: per adapter instance
> + *
> + * Returns zero on success, non-zero on failure
> + */
> +static int ufshcd_dme_reset(struct ufs_hba *hba)
> +{
> + struct uic_command uic_cmd = {0};
> + int ret;
> +
> + uic_cmd.command = UIC_CMD_DME_RESET;
> +
> + ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
> + if (ret)
> + dev_err(hba->dev, "%s: error code %d\n", __func__, ret);
> +
> + return ret;
> +
> +}
> +
> +/**
> + * ufshcd_dme_enable - Local UniPro DME Enable
> + * @hba: per adapter instance
> + *
> + * Returns zero on success, non-zero on failure
> + */
> +static int ufshcd_dme_enable(struct ufs_hba *hba)
> +{
> + struct uic_command uic_cmd = {0};
> + int ret;
> + uic_cmd.command = UIC_CMD_DME_ENABLE;
> +
> + ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
> + if (ret)
> + dev_err(hba->dev, "%s: error code %d\n", __func__, ret);
> +
> + return ret;
> +
> +}
> +
> +/**
> + * ufshcd_device_reset_and_restore - reset and restore device
> + * @hba: per-adapter instance
> + *
> + * Note that the device reset issues DME_END_POINT_RESET which
> + * may reset entire device and restore device attributes to
> + * default state.
> + *
> + * Returns zero on success, non-zero on failure
> + */
> +static int ufshcd_device_reset_and_restore(struct ufs_hba *hba)
> +{
> + int err = 0;
> + u32 reg;
> +
> + err = ufshcd_dme_end_point_reset(hba);
> + if (err)
> + goto out;
> +
> + /* restore communication with the device */
> + err = ufshcd_dme_reset(hba);
> + if (err)
> goto out;
> - } else {
> - err = SUCCESS;
> - }
>
> - for (pos = 0; pos < hba->nutrs; pos++) {
> - if (test_bit(pos, &hba->outstanding_reqs) &&
> - (hba->lrb[tag].lun == hba->lrb[pos].lun)) {
> + err = ufshcd_dme_enable(hba);
> + if (err)
> + goto out;
>
> - /* clear the respective UTRLCLR register bit */
> - ufshcd_utrl_clear(hba, pos);
> + err = ufshcd_dme_link_startup(hba);
UFS_LOGICAL_RESET is no more used?
ufshcd_device_reset_and_restore have a role of device reset.
Both ufshcd_dme_reset and ufshcd_dme_enable are valid for local one, not for remote.
Should we do those for host including link-startup here?
> + if (err)
> + goto out;
>
> - clear_bit(pos, &hba->outstanding_reqs);
> + /* check if link is up and device is detected */
> + reg = ufshcd_readl(hba, REG_CONTROLLER_STATUS);
> + if (!ufshcd_is_device_present(reg)) {
> + dev_err(hba->dev, "Device not present\n");
> + err = -ENXIO;
> + goto out;
> + }
>
> - if (hba->lrb[pos].cmd) {
> - scsi_dma_unmap(hba->lrb[pos].cmd);
> - hba->lrb[pos].cmd->result =
> - DID_ABORT << 16;
> - hba->lrb[pos].cmd->scsi_done(cmd);
> - hba->lrb[pos].cmd = NULL;
> - clear_bit_unlock(pos, &hba->lrb_in_use);
> - wake_up(&hba->dev_cmd.tag_wq);
> - }
> - }
> - } /* end of for */
> + ufshcd_clear_device_reset_pending(hba);
> out:
> + dev_dbg(hba->dev, "%s: done err = %d\n", __func__, err);
> return err;
> }
>
> /**
> - * ufshcd_host_reset - Main reset function registered with scsi layer
> - * @cmd: SCSI command pointer
> + * ufshcd_host_reset_and_restore - reset and restore host controller
> + * @hba: per-adapter instance
> *
> - * Returns SUCCESS/FAILED
> + * Note that host controller reset may issue DME_RESET to
> + * local and remote (device) Uni-Pro stack and the attributes
> + * are reset to default state.
> + *
> + * Returns zero on success, non-zero on failure
> */
> -static int ufshcd_host_reset(struct scsi_cmnd *cmd)
> +static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
> {
> - struct ufs_hba *hba;
> + int err;
> + async_cookie_t cookie;
> + unsigned long flags;
>
> - hba = shost_priv(cmd->device->host);
> + /* Reset the host controller */
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + ufshcd_hba_stop(hba);
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
>
> - if (hba->ufshcd_state == UFSHCD_STATE_RESET)
> - return SUCCESS;
> + err = ufshcd_hba_enable(hba);
> + if (err)
> + goto out;
>
> - return ufshcd_do_reset(hba);
> + /* Establish the link again and restore the device */
> + cookie = async_schedule(ufshcd_async_scan, hba);
> + /* wait for async scan to be completed */
> + async_synchronize_cookie(++cookie);
> + if (hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL)
> + err = -EIO;
> +out:
> + if (err)
> + dev_err(hba->dev, "%s: Host init failed %d\n", __func__, err);
> + else
> + ufshcd_clear_host_reset_pending(hba);
> +
> + dev_dbg(hba->dev, "%s: done err = %d\n", __func__, err);
> + return err;
> }
>
> /**
> @@ -2644,6 +2861,134 @@ out:
> }
>
> /**
> + * ufshcd_reset_and_restore - resets device or host or both
> + * @hba: per-adapter instance
> + *
> + * Reset and recover device, host and re-establish link. This
> + * is helpful to recover the communication in fatal error conditions.
> + *
> + * Returns zero on success, non-zero on failure
> + */
> +static int ufshcd_reset_and_restore(struct ufs_hba *hba)
> +{
> + int err = 0;
> +
> + if (ufshcd_device_reset_pending(hba) &&
> + !ufshcd_host_reset_pending(hba)) {
> + err = ufshcd_device_reset_and_restore(hba);
> + if (err) {
> + ufshcd_clear_device_reset_pending(hba);
> + ufshcd_set_host_reset_pending(hba);
> + }
> + }
> +
> + if (ufshcd_host_reset_pending(hba))
> + err = ufshcd_host_reset_and_restore(hba);
> +
> + /*
> + * Due to reset the door-bell might be cleared, clear
> + * outstanding requests in s/w here.
> + */
> + ufshcd_complete_pending_reqs(hba);
After above, pending requests will be completed by ufshcd_transfer_req_compl.
'cmd->result' which is reported to scsi mid-layer should be a failure.
I think it may not be guaranteed.
> + ufshcd_complete_pending_tasks(hba);
> +
> + return err;
> +}
> +
> +/**
> + * ufshcd_eh_device_reset_handler - device reset handler registered to
> + * scsi layer.
> + * @cmd - SCSI command pointer
> + *
> + * Returns SUCCESS/FAILED
> + */
> +static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd)
> +{
> + struct ufs_hba *hba;
> + int err;
> + unsigned long flags;
> +
> + hba = shost_priv(cmd->device->host);
> +
> + /*
> + * Check if there is any race with fatal error handling.
> + * If so, wait for it to complete. Even though fatal error
> + * handling does reset and restore in some cases, don't assume
> + * anything out of it. We are just avoiding race here.
> + */
> + do {
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + if (!(work_pending(&hba->feh_workq) ||
> + hba->ufshcd_state == UFSHCD_STATE_RESET))
> + break;
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> + dev_dbg(hba->dev, "%s: reset in progress\n", __func__);
> + flush_work_sync(&hba->feh_workq);
> + } while (1);
> +
> + hba->ufshcd_state = UFSHCD_STATE_RESET;
> + ufshcd_set_device_reset_pending(hba);
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> +
> + err = ufshcd_reset_and_restore(hba);
> +
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + if (!err) {
> + err = SUCCESS;
> + hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
> + } else {
> + err = FAILED;
> + hba->ufshcd_state = UFSHCD_STATE_ERROR;
> + }
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> +
> + return err;
> +}
> +
> +/**
> + * ufshcd_eh_host_reset_handler - host reset handler registered to scsi layer
> + * @cmd - SCSI command pointer
> + *
> + * Returns SUCCESS/FAILED
> + */
> +static int ufshcd_eh_host_reset_handler(struct scsi_cmnd *cmd)
> +{
> + struct ufs_hba *hba;
> + int err;
> + unsigned long flags;
> +
> + hba = shost_priv(cmd->device->host);
> +
> + do {
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + if (!(work_pending(&hba->feh_workq) ||
> + hba->ufshcd_state == UFSHCD_STATE_RESET))
> + break;
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> + dev_dbg(hba->dev, "%s: reset in progress\n", __func__);
> + flush_work_sync(&hba->feh_workq);
> + } while (1);
> +
> + hba->ufshcd_state = UFSHCD_STATE_RESET;
> + ufshcd_set_host_reset_pending(hba);
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> +
> + err = ufshcd_reset_and_restore(hba);
> +
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + if (!err) {
> + err = SUCCESS;
> + hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
> + } else {
> + err = FAILED;
> + hba->ufshcd_state = UFSHCD_STATE_ERROR;
> + }
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> +
> + return err;
> +}
Both 'ufshcd_eh_device_reset_handler' and 'ufshcd_eh_host_reset_handler' have
common routine. If possible, it would be better to gather in one function.
> +
> +/**
> * ufshcd_async_scan - asynchronous execution for link startup
> * @data: data pointer to pass to this function
> * @cookie: cookie data
> @@ -2667,8 +3012,14 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
>
> hba->auto_bkops_enabled = false;
> ufshcd_enable_auto_bkops(hba);
> - scsi_scan_host(hba->host);
> - pm_runtime_put_sync(hba->dev);
> + hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
lock is no needed?
Thanks,
Seungwon Jeon
> +
> + /* If we are in error handling context no need to scan the host */
> + if (!(ufshcd_device_reset_pending(hba) ||
> + ufshcd_host_reset_pending(hba))) {
> + scsi_scan_host(hba->host);
> + pm_runtime_put_sync(hba->dev);
> + }
> out:
> return;
> }
> @@ -2681,8 +3032,8 @@ static struct scsi_host_template ufshcd_driver_template = {
> .slave_alloc = ufshcd_slave_alloc,
> .slave_destroy = ufshcd_slave_destroy,
> .eh_abort_handler = ufshcd_abort,
> - .eh_device_reset_handler = ufshcd_device_reset,
> - .eh_host_reset_handler = ufshcd_host_reset,
> + .eh_device_reset_handler = ufshcd_eh_device_reset_handler,
> + .eh_host_reset_handler = ufshcd_eh_host_reset_handler,
> .this_id = -1,
> .sg_tablesize = SG_ALL,
> .cmd_per_lun = UFSHCD_CMD_PER_LUN,
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 5d4542c..7fcedd0 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -179,6 +179,7 @@ struct ufs_dev_cmd {
> * @tm_condition: condition variable for task management
> * @tm_slots_in_use: bit map of task management request slots in use
> * @ufshcd_state: UFSHCD states
> + * @eh_flags: Error handling flags
> * @intr_mask: Interrupt Mask Bits
> * @ee_ctrl_mask: Exception event control mask
> * @feh_workq: Work queue for fatal controller error handling
> @@ -224,6 +225,7 @@ struct ufs_hba {
> unsigned long tm_slots_in_use;
>
> u32 ufshcd_state;
> + u32 eh_flags;
> u32 intr_mask;
> u16 ee_ctrl_mask;
>
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