RE: [PATCH V3 1/1] scsi: ufs: Add support for sending NOP OUT UPIU

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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 <sthumma@xxxxxxxxxxxxxx>
> 
> ---
> 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;
>  };
> 
>  /**
> --
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> of Code Aurora Forum, hosted by The Linux Foundation.
> 
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