RE: [PATCH V5 4/4] scsi: ufs: Improve UFS fatal error handling

["Yaniv Gardi" <ygardi@codeaurora.org>]

Reviewed-by: Yaniv Gardi <ygardi@codeaurora.org>

QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation


= > -----Original Message-----
= > From: linux-scsi-owner@vger.kernel.org [mailto:linux-scsi-
= > owner@vger.kernel.org] On Behalf Of Dolev Raviv
= > Sent: Monday, August 12, 2013 4:03 PM
= > To: Sujit Reddy Thumma
= > Cc: Vinayak Holikatti; Santosh Y; James E.J. Bottomley; linux-
= > scsi@vger.kernel.org; Sujit Reddy Thumma; linux-arm-
= > msm@vger.kernel.org
= > Subject: Re: [PATCH V5 4/4] scsi: ufs: Improve UFS fatal error handling
= > 
= > Tested-by: Dolev Raviv <draviv@codeaurora.org>
= > 
= > > Error handling in UFS driver is broken and resets the host controller
= > > for fatal errors without re-initialization. Correct the fatal error
= > > handling sequence according to UFS Host Controller Interface (HCI)
= > > v1.1 specification.
= > >
= > > o Processed requests which are completed w/wo error are reported to
= > >   SCSI layer and any pending commands that are not started are aborted
= > >   in the controller and re-queued into scsi mid-layer queue.
= > >
= > > o Upon determining fatal error condition the host controller may hang
= > >   forever until a reset is applied. Block SCSI layer for sending new
= > >   requests and apply reset in a separate error handling work.
= > >
= > > o SCSI is informed about the expected Unit-Attention exception from
the
= > >   device for the immediate command after a reset so that the SCSI
layer
= > >   take necessary steps to establish communication with the device.
= > >
= > > Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
= > > ---
= > >  drivers/scsi/ufs/ufshcd.c |  229
= > > ++++++++++++++++++++++++++++-----------------
= > >  drivers/scsi/ufs/ufshcd.h |   10 ++-
= > >  2 files changed, 149 insertions(+), 90 deletions(-)
= > >
= > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
= > > index c577e6e..4dca9b4 100644
= > > --- a/drivers/scsi/ufs/ufshcd.c
= > > +++ b/drivers/scsi/ufs/ufshcd.c
= > > @@ -79,6 +79,14 @@ enum {
= > >  	UFSHCD_EH_IN_PROGRESS = (1 << 0),
= > >  };
= > >
= > > +/* UFSHCD UIC layer error flags */
= > > +enum {
= > > +	UFSHCD_UIC_DL_PA_INIT_ERROR = (1 << 0), /* Data link layer
= > error */
= > > +	UFSHCD_UIC_NL_ERROR = (1 << 1), /* Network layer error */
= > > +	UFSHCD_UIC_TL_ERROR = (1 << 2), /* Transport Layer error */
= > > +	UFSHCD_UIC_DME_ERROR = (1 << 3), /* DME error */ };
= > > +
= > >  /* Interrupt configuration options */  enum {
= > >  	UFSHCD_INT_DISABLE,
= > > @@ -101,6 +109,8 @@ enum {
= > >
= > >  static void ufshcd_tmc_handler(struct ufs_hba *hba);  static void
= > > ufshcd_async_scan(void *data, async_cookie_t cookie);
= > > +static int ufshcd_reset_and_restore(struct ufs_hba *hba); static int
= > > +ufshcd_clear_tm_cmd(struct ufs_hba *hba, int tag);
= > >
= > >  /*
= > >   * ufshcd_wait_for_register - wait for register value to change @@
= > > -1523,9 +1533,6 @@ static int ufshcd_make_hba_operational(struct
= > > ufs_hba *hba)
= > >  		goto out;
= > >  	}
= > >
= > > -	if (hba->ufshcd_state == UFSHCD_STATE_RESET)
= > > -		scsi_unblock_requests(hba->host);
= > > -
= > >  out:
= > >  	return err;
= > >  }
= > > @@ -1651,66 +1658,6 @@ static int ufshcd_verify_dev_init(struct
= > > ufs_hba
= > > *hba)
= > >  }
= > >
= > >  /**
= > > - * ufshcd_do_reset - reset the host controller
= > > - * @hba: per adapter instance
= > > - *
= > > - * Returns SUCCESS/FAILED
= > > - */
= > > -static int ufshcd_do_reset(struct ufs_hba *hba) -{
= > > -	struct ufshcd_lrb *lrbp;
= > > -	unsigned long flags;
= > > -	int tag;
= > > -
= > > -	/* block commands from midlayer */
= > > -	scsi_block_requests(hba->host);
= > > -
= > > -	spin_lock_irqsave(hba->host->host_lock, flags);
= > > -	hba->ufshcd_state = UFSHCD_STATE_RESET;
= > > -
= > > -	/* send controller to reset state */
= > > -	ufshcd_hba_stop(hba);
= > > -	spin_unlock_irqrestore(hba->host->host_lock, flags);
= > > -
= > > -	/* abort outstanding commands */
= > > -	for (tag = 0; tag < hba->nutrs; tag++) {
= > > -		if (test_bit(tag, &hba->outstanding_reqs)) {
= > > -			lrbp = &hba->lrb[tag];
= > > -			if (lrbp->cmd) {
= > > -				scsi_dma_unmap(lrbp->cmd);
= > > -				lrbp->cmd->result = DID_RESET << 16;
= > > -				lrbp->cmd->scsi_done(lrbp->cmd);
= > > -				lrbp->cmd = NULL;
= > > -				clear_bit_unlock(tag, &hba->lrb_in_use);
= > > -			}
= > > -		}
= > > -	}
= > > -
= > > -	/* complete device management command */
= > > -	if (hba->dev_cmd.complete)
= > > -		complete(hba->dev_cmd.complete);
= > > -
= > > -	/* clear outstanding request/task bit maps */
= > > -	hba->outstanding_reqs = 0;
= > > -	hba->outstanding_tasks = 0;
= > > -
= > > -	/* Host controller enable */
= > > -	if (ufshcd_hba_enable(hba)) {
= > > -		dev_err(hba->dev,
= > > -			"Reset: Controller initialization failed\n");
= > > -		return FAILED;
= > > -	}
= > > -
= > > -	if (ufshcd_link_startup(hba)) {
= > > -		dev_err(hba->dev,
= > > -			"Reset: Link start-up failed\n");
= > > -		return FAILED;
= > > -	}
= > > -
= > > -	return SUCCESS;
= > > -}
= > > -
= > > -/**
= > >   * ufshcd_slave_alloc - handle initial SCSI device configurations
= > >   * @sdev: pointer to SCSI device
= > >   *
= > > @@ -1727,6 +1674,9 @@ static int ufshcd_slave_alloc(struct scsi_device
= > > *sdev)
= > >  	sdev->use_10_for_ms = 1;
= > >  	scsi_set_tag_type(sdev, MSG_SIMPLE_TAG);
= > >
= > > +	/* allow SCSI layer to restart the device in case of errors */
= > > +	sdev->allow_restart = 1;
= > > +
= > >  	/*
= > >  	 * Inform SCSI Midlayer that the LUN queue depth is same as the
= > >  	 * controller queue depth. If a LUN queue depth is less than the
= > @@
= > > -1930,6 +1880,9 @@ ufshcd_transfer_rsp_status(struct ufs_hba *hba,
= > > struct ufshcd_lrb *lrbp)
= > >  	case OCS_ABORTED:
= > >  		result |= DID_ABORT << 16;
= > >  		break;
= > > +	case OCS_INVALID_COMMAND_STATUS:
= > > +		result |= DID_REQUEUE << 16;
= > > +		break;
= > >  	case OCS_INVALID_CMD_TABLE_ATTR:
= > >  	case OCS_INVALID_PRDT_ATTR:
= > >  	case OCS_MISMATCH_DATA_BUF_SIZE:
= > > @@ -2241,45 +2194,145 @@ out:
= > >  }
= > >
= > >  /**
= > > - * ufshcd_fatal_err_handler - handle fatal errors
= > > - * @hba: per adapter instance
= > > + * ufshcd_err_handler - handle UFS errors that require s/w attention
= > > + * @work: pointer to work structure
= > >   */
= > > -static void ufshcd_fatal_err_handler(struct work_struct *work)
= > > +static void ufshcd_err_handler(struct work_struct *work)
= > >  {
= > >  	struct ufs_hba *hba;
= > > -	hba = container_of(work, struct ufs_hba, feh_workq);
= > > +	unsigned long flags;
= > > +	u32 err_xfer = 0;
= > > +	u32 err_tm = 0;
= > > +	int err = 0;
= > > +	int tag;
= > > +
= > > +	hba = container_of(work, struct ufs_hba, eh_work);
= > >
= > >  	pm_runtime_get_sync(hba->dev);
= > > -	/* check if reset is already in progress */
= > > -	if (hba->ufshcd_state != UFSHCD_STATE_RESET)
= > > -		ufshcd_do_reset(hba);
= > > +
= > > +	spin_lock_irqsave(hba->host->host_lock, flags);
= > > +	if (hba->ufshcd_state == UFSHCD_STATE_RESET) {
= > > +		spin_unlock_irqrestore(hba->host->host_lock, flags);
= > > +		goto out;
= > > +	}
= > > +
= > > +	hba->ufshcd_state = UFSHCD_STATE_RESET;
= > > +	ufshcd_set_eh_in_progress(hba);
= > > +
= > > +	/* Complete requests that have door-bell cleared by h/w */
= > > +	ufshcd_transfer_req_compl(hba);
= > > +	ufshcd_tmc_handler(hba);
= > > +	spin_unlock_irqrestore(hba->host->host_lock, flags);
= > > +
= > > +	/* Clear pending transfer requests */
= > > +	for_each_set_bit(tag, &hba->outstanding_reqs, hba->nutrs)
= > > +		if (ufshcd_clear_cmd(hba, tag))
= > > +			err_xfer |= 1 << tag;
= > > +
= > > +	/* Clear pending task management requests */
= > > +	for_each_set_bit(tag, &hba->outstanding_tasks, hba->nutmrs)
= > > +		if (ufshcd_clear_tm_cmd(hba, tag))
= > > +			err_tm |= 1 << tag;
= > > +
= > > +	/* Complete the requests that are cleared by s/w */
= > > +	spin_lock_irqsave(hba->host->host_lock, flags);
= > > +	ufshcd_transfer_req_compl(hba);
= > > +	ufshcd_tmc_handler(hba);
= > > +	spin_unlock_irqrestore(hba->host->host_lock, flags);
= > > +
= > > +	/* Fatal errors need reset */
= > > +	if (err_xfer || err_tm || (hba->saved_err & INT_FATAL_ERRORS) ||
= > > +			((hba->saved_err & UIC_ERROR) &&
= > > +			 (hba->saved_uic_err &
= > UFSHCD_UIC_DL_PA_INIT_ERROR))) {
= > > +		err = ufshcd_reset_and_restore(hba);
= > > +		if (err) {
= > > +			dev_err(hba->dev, "%s: reset and restore failed\n",
= > > +					__func__);
= > > +			hba->ufshcd_state = UFSHCD_STATE_ERROR;
= > > +		}
= > > +		/*
= > > +		 * Inform scsi mid-layer that we did reset and allow to
= > handle
= > > +		 * Unit Attention properly.
= > > +		 */
= > > +		scsi_report_bus_reset(hba->host, 0);
= > > +		hba->saved_err = 0;
= > > +		hba->saved_uic_err = 0;
= > > +	}
= > > +	ufshcd_clear_eh_in_progress(hba);
= > > +
= > > +out:
= > > +	scsi_unblock_requests(hba->host);
= > >  	pm_runtime_put_sync(hba->dev);
= > >  }
= > >
= > >  /**
= > > - * ufshcd_err_handler - Check for fatal errors
= > > - * @work: pointer to a work queue structure
= > > + * ufshcd_update_uic_error - check and set fatal UIC error flags.
= > > + * @hba: per-adapter instance
= > >   */
= > > -static void ufshcd_err_handler(struct ufs_hba *hba)
= > > +static void ufshcd_update_uic_error(struct ufs_hba *hba)
= > >  {
= > >  	u32 reg;
= > >
= > > +	/* PA_INIT_ERROR is fatal and needs UIC reset */
= > > +	reg = ufshcd_readl(hba,
= > REG_UIC_ERROR_CODE_DATA_LINK_LAYER);
= > > +	if (reg & UIC_DATA_LINK_LAYER_ERROR_PA_INIT)
= > > +		hba->uic_error |= UFSHCD_UIC_DL_PA_INIT_ERROR;
= > > +
= > > +	/* UIC NL/TL/DME errors needs software retry */
= > > +	reg = ufshcd_readl(hba,
= > REG_UIC_ERROR_CODE_NETWORK_LAYER);
= > > +	if (reg)
= > > +		hba->uic_error |= UFSHCD_UIC_NL_ERROR;
= > > +
= > > +	reg = ufshcd_readl(hba,
= > REG_UIC_ERROR_CODE_TRANSPORT_LAYER);
= > > +	if (reg)
= > > +		hba->uic_error |= UFSHCD_UIC_TL_ERROR;
= > > +
= > > +	reg = ufshcd_readl(hba, REG_UIC_ERROR_CODE_DME);
= > > +	if (reg)
= > > +		hba->uic_error |= UFSHCD_UIC_DME_ERROR;
= > > +
= > > +	dev_dbg(hba->dev, "%s: UIC error flags = 0x%08x\n",
= > > +			__func__, hba->uic_error);
= > > +}
= > > +
= > > +/**
= > > + * ufshcd_check_errors - Check for errors that need s/w attention
= > > + * @hba: per-adapter instance
= > > + */
= > > +static void ufshcd_check_errors(struct ufs_hba *hba) {
= > > +	bool queue_eh_work = false;
= > > +
= > >  	if (hba->errors & INT_FATAL_ERRORS)
= > > -		goto fatal_eh;
= > > +		queue_eh_work = true;
= > >
= > >  	if (hba->errors & UIC_ERROR) {
= > > -		reg = ufshcd_readl(hba,
= > REG_UIC_ERROR_CODE_DATA_LINK_LAYER);
= > > -		if (reg & UIC_DATA_LINK_LAYER_ERROR_PA_INIT)
= > > -			goto fatal_eh;
= > > +		hba->uic_error = 0;
= > > +		ufshcd_update_uic_error(hba);
= > > +		if (hba->uic_error)
= > > +			queue_eh_work = true;
= > >  	}
= > > -	return;
= > > -fatal_eh:
= > > -	/* 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;
= > > -		schedule_work(&hba->feh_workq);
= > > +
= > > +	if (queue_eh_work) {
= > > +		/* handle fatal errors only when link is functional */
= > > +		if (hba->ufshcd_state == UFSHCD_STATE_OPERATIONAL) {
= > > +			/* block commands from scsi mid-layer */
= > > +			scsi_block_requests(hba->host);
= > > +
= > > +			/* transfer error masks to sticky bits */
= > > +			hba->saved_err |= hba->errors;
= > > +			hba->saved_uic_err |= hba->uic_error;
= > > +
= > > +			hba->ufshcd_state = UFSHCD_STATE_ERROR;
= > > +			schedule_work(&hba->eh_work);
= > > +		}
= > >  	}
= > > +	/*
= > > +	 * if (!queue_eh_work) -
= > > +	 * Other errors are either non-fatal where host recovers
= > > +	 * itself without s/w intervention or errors that will be
= > > +	 * handled by the SCSI core layer.
= > > +	 */
= > >  }
= > >
= > >  /**
= > > @@ -2304,7 +2357,7 @@ static void ufshcd_sl_intr(struct ufs_hba *hba,
= > > u32
= > > intr_status)
= > >  {
= > >  	hba->errors = UFSHCD_ERROR_MASK & intr_status;
= > >  	if (hba->errors)
= > > -		ufshcd_err_handler(hba);
= > > +		ufshcd_check_errors(hba);
= > >
= > >  	if (intr_status & UIC_COMMAND_COMPL)
= > >  		ufshcd_uic_cmd_compl(hba);
= > > @@ -2679,12 +2732,12 @@ static int
= > ufshcd_eh_host_reset_handler(struct
= > > scsi_cmnd *cmd)
= > >  	 */
= > >  	do {
= > >  		spin_lock_irqsave(hba->host->host_lock, flags);
= > > -		if (!(work_pending(&hba->feh_workq) ||
= > > +		if (!(work_pending(&hba->eh_work) ||
= > >  				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);
= > > +		flush_work_sync(&hba->eh_work);
= > >  	} while (1);
= > >
= > >  	hba->ufshcd_state = UFSHCD_STATE_RESET; @@ -2918,7 +2971,7
= > @@ int
= > > ufshcd_init(struct device *dev, struct ufs_hba **hba_handle,
= > >  	init_waitqueue_head(&hba->tm_tag_wq);
= > >
= > >  	/* Initialize work queues */
= > > -	INIT_WORK(&hba->feh_workq, ufshcd_fatal_err_handler);
= > > +	INIT_WORK(&hba->eh_work, ufshcd_err_handler);
= > >  	INIT_WORK(&hba->eeh_work, ufshcd_exception_event_handler);
= > >
= > >  	/* Initialize UIC command mutex */
= > > diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
= > > index 1e0585c..8f5624e 100644
= > > --- a/drivers/scsi/ufs/ufshcd.h
= > > +++ b/drivers/scsi/ufs/ufshcd.h
= > > @@ -182,9 +182,12 @@ struct ufs_dev_cmd {
= > >   * @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
= > > + * @eh_work: Worker to handle UFS errors that require s/w attention
= > >   * @eeh_work: Worker to handle exception events
= > >   * @errors: HBA errors
= > > + * @uic_error: UFS interconnect layer error status
= > > + * @saved_err: sticky error mask
= > > + * @saved_uic_err: sticky UIC error mask
= > >   * @dev_cmd: ufs device management command information
= > >   * @auto_bkops_enabled: to track whether bkops is enabled in device
= > >   */
= > > @@ -230,11 +233,14 @@ struct ufs_hba {
= > >  	u16 ee_ctrl_mask;
= > >
= > >  	/* Work Queues */
= > > -	struct work_struct feh_workq;
= > > +	struct work_struct eh_work;
= > >  	struct work_struct eeh_work;
= > >
= > >  	/* HBA Errors */
= > >  	u32 errors;
= > > +	u32 uic_error;
= > > +	u32 saved_err;
= > > +	u32 saved_uic_err;
= > >
= > >  	/* Device management request data */
= > >  	struct ufs_dev_cmd dev_cmd;
= > > --
= > > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
= > > member of Code Aurora Forum, hosted by The Linux Foundation.
= > >
= > > --
= > > To unsubscribe from this list: send the line "unsubscribe linux-scsi"
= > > in the body of a message to majordomo@vger.kernel.org More
= > majordomo
= > > info at  http://vger.kernel.org/majordomo-info.html
= > >
= > 
= > 
= > --
= > QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a
= > member of Code Aurora Forum, hosted by The Linux Foundation
= > 
= > --
= > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
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