On Monday, May 06, 2013, Sujit Reddy Thumma wrote:
> As part of device initialization sequence, sending NOP OUT UPIU and
> waiting for NOP IN UPIU response is mandatory. This confirms that the
> device UFS Transport (UTP) layer is functional and the host can configure
> the device with further commands. Add support for sending NOP OUT UPIU to
> check the device connection path and test whether the UTP layer on the
> device side is functional during initialization.
> 
> Signed-off-by: Sujit Reddy Thumma <sthu...@codeaurora.org>
> 
> ---
> v3:
>    - minor bug fix in error path
> v2:
>    - fixed INTERNAL_CMD_TAG check in readl_poll_timeout
>    - minor cleanup from v1
>    - rebased on Seungwon Jeon's UFS V3 patchset
> ---
>  drivers/scsi/ufs/ufshcd.c |  163 
> ++++++++++++++++++++++++++++++++++++++++++---
>  drivers/scsi/ufs/ufshcd.h |    4 +
>  2 files changed, 158 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 3607ffb..4090f6c 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -34,6 +34,7 @@
>   */
> 
>  #include <linux/async.h>
> +#include <linux/iopoll.h>
linux/iopoll.h: No such file or directory
Please check.

> 
>  #include "ufshcd.h"
> 
> @@ -44,6 +45,13 @@
>  /* UIC command timeout, unit: ms */
>  #define UIC_CMD_TIMEOUT      500
> 
> +/* NOP OUT retries waiting for NOP IN response */
> +#define NOP_OUT_RETRIES    10
> +/* Timeout after 30 msecs if NOP OUT hangs without response */
> +#define NOP_OUT_TIMEOUT    30 /* msecs */
> +/* Reserved tag for internal commands */
> +#define INTERNAL_CMD_TAG   0
> +
>  enum {
>       UFSHCD_MAX_CHANNEL      = 0,
>       UFSHCD_MAX_ID           = 1,
> @@ -630,7 +638,7 @@ static void ufshcd_prepare_req_desc(struct ufshcd_lrb 
> *lrbp, u32 *upiu_flags)
>  {
>       struct utp_transfer_req_desc *req_desc = lrbp->utr_descriptor_ptr;
>       enum dma_data_direction cmd_dir =
> -             lrbp->cmd->sc_data_direction;
> +             lrbp->cmd ? lrbp->cmd->sc_data_direction : DMA_NONE;
>       u32 data_direction;
>       u32 dword_0;
> 
> @@ -647,6 +655,8 @@ static void ufshcd_prepare_req_desc(struct ufshcd_lrb 
> *lrbp, u32 *upiu_flags)
> 
>       dword_0 = data_direction | (lrbp->command_type
>                               << UPIU_COMMAND_TYPE_OFFSET);
> +     if (lrbp->intr_cmd)
> +             dword_0 |= UTP_REQ_DESC_INT_CMD;
> 
>       /* Transfer request descriptor header fields */
>       req_desc->header.dword_0 = cpu_to_le32(dword_0);
> @@ -735,6 +745,18 @@ static void ufshcd_prepare_utp_query_req_upiu(struct 
> ufs_hba *hba,
> 
>  }
> 
> +static inline void ufshcd_prepare_utp_nop_upiu(struct ufshcd_lrb *lrbp)
> +{
> +     struct utp_upiu_req *ucd_req_ptr = lrbp->ucd_req_ptr;
> +
> +     memset(ucd_req_ptr, 0, sizeof(struct utp_upiu_req));
> +
> +     /* command descriptor fields */
> +     ucd_req_ptr->header.dword_0 =
> +             UPIU_HEADER_DWORD(
> +                     UPIU_TRANSACTION_NOP_OUT, 0, 0, lrbp->task_tag);
> +}
> +
>  /**
>   * ufshcd_compose_upiu - form UFS Protocol Information Unit(UPIU)
>   * @hba - UFS hba
> @@ -749,11 +771,13 @@ static int ufshcd_compose_upiu(struct ufs_hba *hba, 
> struct ufshcd_lrb *lrbp)
>       case UTP_CMD_TYPE_SCSI:
>       case UTP_CMD_TYPE_DEV_MANAGE:
>               ufshcd_prepare_req_desc(lrbp, &upiu_flags);
> -             if (lrbp->command_type == UTP_CMD_TYPE_SCSI)
> +             if (lrbp->cmd && lrbp->command_type == UTP_CMD_TYPE_SCSI)
>                       ufshcd_prepare_utp_scsi_cmd_upiu(lrbp, upiu_flags);
> -             else
> +             else if (lrbp->cmd && ufshcd_is_query_req(lrbp))
>                       ufshcd_prepare_utp_query_req_upiu(hba, lrbp,
>                                                               upiu_flags);
> +             else if (!lrbp->cmd)
> +                     ufshcd_prepare_utp_nop_upiu(lrbp);
>               break;
>       case UTP_CMD_TYPE_UFS:
>               /* For UFS native command implementation */
> @@ -802,6 +826,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, 
> struct scsi_cmnd *cmd)
>       lrbp->sense_buffer = cmd->sense_buffer;
>       lrbp->task_tag = tag;
>       lrbp->lun = cmd->device->lun;
> +     lrbp->intr_cmd = false;
> 
>       if (ufshcd_is_query_req(lrbp))
>               lrbp->command_type = UTP_CMD_TYPE_DEV_MANAGE;
> @@ -1261,6 +1286,103 @@ int ufshcd_dme_endpt_reset(struct ufs_hba *hba)
>  }
>  EXPORT_SYMBOL_GPL(ufshcd_dme_endpt_reset);
> 
> +static int
> +ufshcd_compose_nop_out_upiu(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
> +{
> +     lrbp->cmd = NULL;
> +     lrbp->sense_bufflen = 0;
> +     lrbp->sense_buffer = NULL;
> +     lrbp->task_tag = INTERNAL_CMD_TAG;
> +     lrbp->lun = 0; /* NOP OUT is not specific to any LUN */
> +     lrbp->command_type = UTP_CMD_TYPE_DEV_MANAGE;
> +     lrbp->intr_cmd = true; /* No interrupt aggregation */
> +
> +     return ufshcd_compose_upiu(hba, lrbp);
> +}
> +
> +static int ufshcd_wait_for_nop_cmd(struct ufs_hba *hba, struct ufshcd_lrb 
> *lrbp)
> +{
> +     int err = 0;
> +     unsigned long timeout;
> +     unsigned long flags;
> +
> +     timeout = wait_for_completion_timeout(
> +                     lrbp->completion, msecs_to_jiffies(NOP_OUT_TIMEOUT));
> +
> +     if (timeout) {
> +             spin_lock_irqsave(hba->host->host_lock, flags);
> +             err = ufshcd_get_tr_ocs(lrbp);
> +             spin_unlock_irqrestore(hba->host->host_lock, flags);
> +     } else {
> +             err = -ETIMEDOUT;
> +     }
> +
> +     return err;
> +}
> +
> +/**
> + * ufshcd_validate_dev_connection() - Check device connection status
> + * @hba: per-adapter instance
> + *
> + * Send NOP OUT UPIU and wait for NOP IN response to check whether the
> + * device Transport Protocol (UTP) layer is ready after a reset.
> + * If the UTP layer at the device side is not initialized, it may
> + * not respond with NOP IN UPIU within timeout of %NOP_OUT_TIMEOUT
> + * and we retry sending NOP OUT for %NOP_OUT_RETRIES iterations.
> + */
> +static int ufshcd_validate_dev_connection(struct ufs_hba *hba)
> +{
> +     int err;
> +     struct ufshcd_lrb *lrbp;
> +     unsigned long flags;
> +     struct completion wait;
> +     int retries = NOP_OUT_RETRIES;
> +
> +retry:
> +     init_completion(&wait);
> +
> +     spin_lock_irqsave(hba->host->host_lock, flags);
> +     lrbp = &hba->lrb[INTERNAL_CMD_TAG];
> +     err = ufshcd_compose_nop_out_upiu(hba, lrbp);
> +     if (unlikely(err)) {
> +             spin_unlock_irqrestore(hba->host->host_lock, flags);
> +             goto out;
> +     }
> +
> +     lrbp->completion = &wait;
> +     ufshcd_send_command(hba, INTERNAL_CMD_TAG);
> +     spin_unlock_irqrestore(hba->host->host_lock, flags);
> +
> +     err = ufshcd_wait_for_nop_cmd(hba, lrbp);
> +
> +     if (err == -ETIMEDOUT) {
> +             u32 reg;
> +
> +             /* clear outstanding transaction before retry */
> +             spin_lock_irqsave(hba->host->host_lock, flags);
> +             ufshcd_utrl_clear(hba, INTERNAL_CMD_TAG);
> +             __clear_bit(INTERNAL_CMD_TAG, &hba->outstanding_reqs);
> +             spin_unlock_irqrestore(hba->host->host_lock, flags);
> +
> +             /* poll for max. 1 sec to clear door bell register by h/w */
> +             if (readl_poll_timeout(
> +                             hba->mmio_base + REG_UTP_TRANSFER_REQ_DOOR_BELL,
> +                             reg, !(reg & (1 << INTERNAL_CMD_TAG)),
> +                             1000, 1000))
> +                     retries = 0;
Also, readl_poll_timeout function is not present in Linux kernel.
Could you check your kernel?
You should implement this part in other way.
Additionally, is there no need to clear 'lrbp->completion'?
It will have invalid value after current function is out.

Thanks,
Seungwon Jeon

> +     }
> +
> +     if (err && retries--) {
> +             dev_dbg(hba->dev, "%s: error %d retrying\n", __func__, err);
> +             goto retry;
> +     }
> +
> +out:
> +     if (err)
> +             dev_err(hba->dev, "%s: NOP OUT failed %d\n", __func__, err);
> +     return err;
> +}
> +
>  /**
>   * ufshcd_make_hba_operational - Make UFS controller operational
>   * @hba: per adapter instance
> @@ -1734,6 +1856,16 @@ static void ufshcd_uic_cmd_compl(struct ufs_hba *hba, 
> u32 intr_status)
>               complete(&hba->hibern8_done);
>  }
> 
> +/*
> + * ufshcd_is_nop_out_upiu() - check if the command is NOP OUT UPIU
> + * @lrbp: pointer to logical reference block
> + */
> +static inline bool ufshcd_is_nop_out_upiu(struct ufshcd_lrb *lrbp)
> +{
> +     return (be32_to_cpu(lrbp->ucd_req_ptr->header.dword_0) >> 24) ==
> +                             UPIU_TRANSACTION_NOP_OUT;
> +}
> +
>  /**
>   * ufshcd_transfer_req_compl - handle SCSI and query command completion
>   * @hba: per adapter instance
> @@ -1745,6 +1877,7 @@ static void ufshcd_transfer_req_compl(struct ufs_hba 
> *hba)
>       u32 tr_doorbell;
>       int result;
>       int index;
> +     bool int_aggr_reset = true;
> 
>       lrb = hba->lrb;
>       tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
> @@ -1752,17 +1885,20 @@ static void ufshcd_transfer_req_compl(struct ufs_hba 
> *hba)
> 
>       for (index = 0; index < hba->nutrs; index++) {
>               if (test_bit(index, &completed_reqs)) {
> -
> -                     result = ufshcd_transfer_rsp_status(hba, &lrb[index]);
> -
>                       if (lrb[index].cmd) {
> +                             result = ufshcd_transfer_rsp_status(
> +                                             hba, &lrb[index]);
>                               scsi_dma_unmap(lrb[index].cmd);
>                               lrb[index].cmd->result = result;
>                               lrb[index].cmd->scsi_done(lrb[index].cmd);
> 
>                               /* Mark completed command as NULL in LRB */
>                               lrb[index].cmd = NULL;
> +                     } else if (ufshcd_is_nop_out_upiu(&lrb[index])) {
> +                             complete(lrb[index].completion);
>                       }
> +                     /* Don't reset counters for interrupt cmd */
> +                     int_aggr_reset = lrb[index].intr_cmd ? false : true;
>               } /* end of if */
>       } /* end of for */
> 
> @@ -1770,7 +1906,8 @@ static void ufshcd_transfer_req_compl(struct ufs_hba 
> *hba)
>       hba->outstanding_reqs ^= completed_reqs;
> 
>       /* Reset interrupt aggregation counters */
> -     ufshcd_config_int_aggr(hba, INT_AGGR_RESET);
> +     if (int_aggr_reset)
> +             ufshcd_config_int_aggr(hba, INT_AGGR_RESET);
>  }
> 
>  /**
> @@ -2068,8 +2205,16 @@ static void ufshcd_async_scan(void *data, 
> async_cookie_t cookie)
>       int ret;
> 
>       ret = ufshcd_link_startup(hba);
> -     if (!ret)
> -             scsi_scan_host(hba->host);
> +     if (ret)
> +             goto out;
> +
> +     ret = ufshcd_validate_dev_connection(hba);
> +     if (ret)
> +             goto out;
> +
> +     scsi_scan_host(hba->host);
> +out:
> +     return;
>  }
> 
>  static struct scsi_host_template ufshcd_driver_template = {
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 84f758e..17f4995 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -102,6 +102,8 @@ struct uic_command {
>   * @command_type: SCSI, UFS, Query.
>   * @task_tag: Task tag of the command
>   * @lun: LUN of the command
> + * @intr_cmd: Interrupt command (doesn't participate in interrupt 
> aggregation)
> + * @completion: holds the state of completion (used for internal commands)
>   */
>  struct ufshcd_lrb {
>       struct utp_transfer_req_desc *utr_descriptor_ptr;
> @@ -117,6 +119,8 @@ struct ufshcd_lrb {
>       int command_type;
>       int task_tag;
>       unsigned int lun;
> +     bool intr_cmd;
> +     struct completion *completion;
>  };
> 
>  /**
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation.
> 
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