Tested-by: Dolev Raviv <dra...@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 <sthu...@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;
> --
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> of Code Aurora Forum, hosted by The Linux Foundation.
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