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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Tested-by: Dolev Raviv <draviv@xxxxxxxxxxxxxx>

> 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@xxxxxxxxxxxxxx>
> ---
>  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@xxxxxxxxxxxxxxx
> 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-arm-msm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [Linux for Sparc]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux