Tested with error injection.
Tested-by: Maya Erez <merez@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 Upon determining fatal error condition the host controller may hang
> forever until a reset is applied, so just retrying the command doesn't
> work without a reset. So, the reset is applied in the driver context
> in a separate work and SCSI mid-layer isn't informed until reset is
> applied.
>
> o Processed requests which are completed without error are reported to
> SCSI layer as successful and any pending commands that are not started
> yet or are not cause of the error are re-queued into scsi midlayer
> queue.
> For the command that caused error, host controller or device is reset
> and DID_ERROR is returned for command retry after applying reset.
>
> o SCSI is informed about the expected Unit-Attentioni 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 | 349
> +++++++++++++++++++++++++++++++++++---------
> drivers/scsi/ufs/ufshcd.h | 2 +
> drivers/scsi/ufs/ufshci.h | 19 ++-
> 3 files changed, 295 insertions(+), 75 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index b4c9910..2a3874f 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -80,6 +80,14 @@ enum {
> UFSHCD_EH_DEVICE_RESET_PENDING = (1 << 1),
> };
>
> +/* 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,
> @@ -108,6 +116,7 @@ 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);
>
> /*
> * ufshcd_wait_for_register - wait for register value to change
> @@ -1605,9 +1614,6 @@ 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;
> }
> @@ -1733,66 +1739,6 @@ static int ufshcd_validate_dev_connection(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
> *
> @@ -1809,6 +1755,9 @@ 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
> @@ -2013,6 +1962,9 @@ 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:
> @@ -2405,42 +2357,295 @@ out:
> return err;
> }
>
> +static void ufshcd_decide_eh_xfer_req(struct ufs_hba *hba, u32 ocs)
> +{
> + switch (ocs) {
> + case OCS_SUCCESS:
> + case OCS_INVALID_COMMAND_STATUS:
> + break;
> + case OCS_MISMATCH_DATA_BUF_SIZE:
> + case OCS_MISMATCH_RESP_UPIU_SIZE:
> + case OCS_PEER_COMM_FAILURE:
> + case OCS_FATAL_ERROR:
> + case OCS_ABORTED:
> + case OCS_INVALID_CMD_TABLE_ATTR:
> + case OCS_INVALID_PRDT_ATTR:
> + ufshcd_set_host_reset_pending(hba);
> + break;
> + default:
> + dev_err(hba->dev, "%s: unknown OCS 0x%x\n",
> + __func__, ocs);
> + BUG();
> + }
> +}
> +
> +static void ufshcd_decide_eh_task_req(struct ufs_hba *hba, u32 ocs)
> +{
> + switch (ocs) {
> + case OCS_TMR_SUCCESS:
> + case OCS_TMR_INVALID_COMMAND_STATUS:
> + break;
> + case OCS_TMR_MISMATCH_REQ_SIZE:
> + case OCS_TMR_MISMATCH_RESP_SIZE:
> + case OCS_TMR_PEER_COMM_FAILURE:
> + case OCS_TMR_INVALID_ATTR:
> + case OCS_TMR_ABORTED:
> + case OCS_TMR_FATAL_ERROR:
> + ufshcd_set_host_reset_pending(hba);
> + break;
> + default:
> + dev_err(hba->dev, "%s: uknown TMR OCS 0x%x\n",
> + __func__, ocs);
> + BUG();
> + }
> +}
> +
> /**
> - * ufshcd_fatal_err_handler - handle fatal errors
> + * ufshcd_error_autopsy_transfer_req() - reads OCS field of failed
> command and
> + * decide error handling
> * @hba: per adapter instance
> + * @err_xfer: bit mask for transfer request errors
> + *
> + * Iterate over completed transfer requests and
> + * set error handling flags.
> + */
> +static void
> +ufshcd_error_autopsy_transfer_req(struct ufs_hba *hba, u32 *err_xfer)
> +{
> + unsigned long completed;
> + u32 doorbell;
> + int index;
> + int ocs;
> +
> + if (!err_xfer)
> + goto out;
> +
> + doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
> + completed = doorbell ^ (u32)hba->outstanding_reqs;
> +
> + for (index = 0; index < hba->nutrs; index++) {
> + if (test_bit(index, &completed)) {
> + ocs = ufshcd_get_tr_ocs(&hba->lrb[index]);
> + if ((ocs == OCS_SUCCESS) ||
> + (ocs == OCS_INVALID_COMMAND_STATUS))
> + continue;
> +
> + *err_xfer |= (1 << index);
> + ufshcd_decide_eh_xfer_req(hba, ocs);
> + }
> + }
> +out:
> + return;
> +}
> +
> +/**
> + * ufshcd_error_autopsy_task_req() - reads OCS field of failed command
> and
> + * decide error handling
> + * @hba: per adapter instance
> + * @err_tm: bit mask for task management errors
> + *
> + * Iterate over completed task management requests and
> + * set error handling flags.
> + */
> +static void
> +ufshcd_error_autopsy_task_req(struct ufs_hba *hba, u32 *err_tm)
> +{
> + unsigned long completed;
> + u32 doorbell;
> + int index;
> + int ocs;
> +
> + if (!err_tm)
> + goto out;
> +
> + doorbell = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL);
> + completed = doorbell ^ (u32)hba->outstanding_tasks;
> +
> + for (index = 0; index < hba->nutmrs; index++) {
> + if (test_bit(index, &completed)) {
> + struct utp_task_req_desc *tm_descp;
> +
> + tm_descp = hba->utmrdl_base_addr;
> + ocs = ufshcd_get_tmr_ocs(&tm_descp[index]);
> + if ((ocs == OCS_TMR_SUCCESS) ||
> + (ocs == OCS_TMR_INVALID_COMMAND_STATUS))
> + continue;
> +
> + *err_tm |= (1 << index);
> + ufshcd_decide_eh_task_req(hba, ocs);
> + }
> + }
> +
> +out:
> + return;
> +}
> +
> +/**
> + * ufshcd_fatal_err_handler - handle fatal errors
> + * @work: pointer to work structure
> */
> static void ufshcd_fatal_err_handler(struct work_struct *work)
> {
> struct ufs_hba *hba;
> + unsigned long flags;
> + u32 err_xfer = 0;
> + u32 err_tm = 0;
> + int err;
> +
> hba = container_of(work, struct ufs_hba, feh_workq);
>
> 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) {
> + /* complete processed requests and exit */
> + ufshcd_transfer_req_compl(hba);
> + ufshcd_tmc_handler(hba);
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> + pm_runtime_put_sync(hba->dev);
> + return;
> + }
> +
> + hba->ufshcd_state = UFSHCD_STATE_RESET;
> + ufshcd_error_autopsy_transfer_req(hba, &err_xfer);
> + ufshcd_error_autopsy_task_req(hba, &err_tm);
> +
> + /*
> + * Complete successful and pending transfer requests.
> + * DID_REQUEUE is returned for pending requests as they have
> + * nothing to do with error'ed request and SCSI layer should
> + * not treat them as errors and decrement retry count.
> + */
> + hba->outstanding_reqs &= ~err_xfer;
> + ufshcd_transfer_req_compl(hba);
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> + ufshcd_complete_pending_reqs(hba);
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + hba->outstanding_reqs |= err_xfer;
> +
> + /* Complete successful and pending task requests */
> + hba->outstanding_tasks &= ~err_tm;
> + ufshcd_tmc_handler(hba);
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> + ufshcd_complete_pending_tasks(hba);
> + spin_lock_irqsave(hba->host->host_lock, flags);
> +
> + hba->outstanding_tasks |= err_tm;
> +
> + /*
> + * Controller may generate multiple fatal errors, handle
> + * errors based on severity.
> + * 1) DEVICE_FATAL_ERROR
> + * 2) SYSTEM_BUS/CONTROLLER_FATAL_ERROR
> + * 3) UIC_ERROR
> + */
> + if (hba->errors & DEVICE_FATAL_ERROR) {
> + /*
> + * Some HBAs may not clear UTRLDBR/UTMRLDBR or update
> + * OCS field on device fatal error.
> + */
> + ufshcd_set_host_reset_pending(hba);
> + } else if (hba->errors & (SYSTEM_BUS_FATAL_ERROR |
> + CONTROLLER_FATAL_ERROR)) {
> + /* eh flags should be set in err autopsy based on OCS values */
> + if (!hba->eh_flags)
> + WARN(1, "%s: fatal error without error handling\n",
> + dev_name(hba->dev));
> + } else if (hba->errors & UIC_ERROR) {
> + if (hba->uic_error & UFSHCD_UIC_DL_PA_INIT_ERROR) {
> + /* fatal error - reset controller */
> + ufshcd_set_host_reset_pending(hba);
> + } else if (hba->uic_error & (UFSHCD_UIC_NL_ERROR |
> + UFSHCD_UIC_TL_ERROR |
> + UFSHCD_UIC_DME_ERROR)) {
> + /* non-fatal, report error to SCSI layer */
> + if (!hba->eh_flags) {
> + spin_unlock_irqrestore(
> + hba->host->host_lock, flags);
> + ufshcd_complete_pending_reqs(hba);
> + ufshcd_complete_pending_tasks(hba);
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + }
> + }
> + }
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> +
> + if (hba->eh_flags) {
> + err = ufshcd_reset_and_restore(hba);
> + if (err) {
> + ufshcd_clear_host_reset_pending(hba);
> + ufshcd_clear_device_reset_pending(hba);
> + 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->errors = 0;
> + hba->uic_error = 0;
> + }
> + 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_err_handler - Check for fatal errors
> + * @hba: per-adapter instance
> + */
> +static void ufshcd_err_handler(struct ufs_hba *hba)
> +{
> if (hba->errors & INT_FATAL_ERRORS)
> goto fatal_eh;
>
> 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)
> + hba->uic_error = 0;
> + ufshcd_update_uic_error(hba);
> + if (hba->uic_error)
> goto fatal_eh;
> }
> + /*
> + * Other errors are either non-fatal or completed by the
> + * controller by updating OCS fields with success/failure.
> + */
> return;
> +
> fatal_eh:
> /* handle fatal errors only when link is functional */
> if (hba->ufshcd_state == UFSHCD_STATE_OPERATIONAL) {
> + /* block commands from midlayer */
> + scsi_block_requests(hba->host);
> /* block commands at driver layer until error is handled */
> hba->ufshcd_state = UFSHCD_STATE_ERROR;
> schedule_work(&hba->feh_workq);
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 7fcedd0..4ee4d1a 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -185,6 +185,7 @@ struct ufs_dev_cmd {
> * @feh_workq: Work queue for fatal controller error handling
> * @eeh_work: Worker to handle exception events
> * @errors: HBA errors
> + * @uic_error: UFS interconnect layer error status
> * @dev_cmd: ufs device management command information
> * @auto_bkops_enabled: to track whether bkops is enabled in device
> */
> @@ -235,6 +236,7 @@ struct ufs_hba {
>
> /* HBA Errors */
> u32 errors;
> + u32 uic_error;
>
> /* Device management request data */
> struct ufs_dev_cmd dev_cmd;
> diff --git a/drivers/scsi/ufs/ufshci.h b/drivers/scsi/ufs/ufshci.h
> index f1e1b74..36f68ef 100644
> --- a/drivers/scsi/ufs/ufshci.h
> +++ b/drivers/scsi/ufs/ufshci.h
> @@ -264,7 +264,7 @@ enum {
> UTP_DEVICE_TO_HOST = 0x04000000,
> };
>
> -/* Overall command status values */
> +/* Overall command status values for transfer request */
> enum {
> OCS_SUCCESS = 0x0,
> OCS_INVALID_CMD_TABLE_ATTR = 0x1,
> @@ -274,8 +274,21 @@ enum {
> OCS_PEER_COMM_FAILURE = 0x5,
> OCS_ABORTED = 0x6,
> OCS_FATAL_ERROR = 0x7,
> - OCS_INVALID_COMMAND_STATUS = 0x0F,
> - MASK_OCS = 0x0F,
> + OCS_INVALID_COMMAND_STATUS = 0xF,
> + MASK_OCS = 0xFF,
> +};
> +
> +/* Overall command status values for task management request */
> +enum {
> + OCS_TMR_SUCCESS = 0x0,
> + OCS_TMR_INVALID_ATTR = 0x1,
> + OCS_TMR_MISMATCH_REQ_SIZE = 0x2,
> + OCS_TMR_MISMATCH_RESP_SIZE = 0x3,
> + OCS_TMR_PEER_COMM_FAILURE = 0x4,
> + OCS_TMR_ABORTED = 0x5,
> + OCS_TMR_FATAL_ERROR = 0x6,
> + OCS_TMR_INVALID_COMMAND_STATUS = 0xF,
> + MASK_OCS_TMR = 0xFF,
> };
>
> /**
> --
> 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
>
--
Maya Erez
QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation
--
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