Re: [PATCH v4 9/9] scsi: ufs: Make .get_hba_mac() optional

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Tue, Jul 02, 2024 at 01:39:17PM -0700, Bart Van Assche wrote:
> UFSHCI controllers that are compliant with the UFSHCI 4.0 standard report
> the maximum number of supported commands in the controller capabilities
> register. Use that value if .get_hba_mac == NULL.
> 
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
>  drivers/ufs/core/ufs-mcq.c     | 20 ++++++++++++++------
>  drivers/ufs/core/ufshcd-priv.h |  1 +
>  drivers/ufs/core/ufshcd.c      |  6 ++++--
>  include/ufs/ufshcd.h           |  4 +++-
>  include/ufs/ufshci.h           |  1 +
>  5 files changed, 23 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/ufs/core/ufs-mcq.c b/drivers/ufs/core/ufs-mcq.c
> index 0482c7a1e419..b2cf34a1fe48 100644
> --- a/drivers/ufs/core/ufs-mcq.c
> +++ b/drivers/ufs/core/ufs-mcq.c
> @@ -138,18 +138,21 @@ EXPORT_SYMBOL_GPL(ufshcd_mcq_queue_cfg_addr);
>   *
>   * MAC - Max. Active Command of the Host Controller (HC)
>   * HC wouldn't send more than this commands to the device.
> - * It is mandatory to implement get_hba_mac() to enable MCQ mode.
>   * Calculates and adjusts the queue depth based on the depth
>   * supported by the HC and ufs device.
>   */
>  int ufshcd_mcq_decide_queue_depth(struct ufs_hba *hba)
>  {
> -	int mac = -EOPNOTSUPP;
> +	int mac;
>  
> -	if (!hba->vops || !hba->vops->get_hba_mac)
> -		goto err;
> -
> -	mac = hba->vops->get_hba_mac(hba);
> +	if (!hba->vops || !hba->vops->get_hba_mac) {
> +		hba->capabilities =
> +			ufshcd_readl(hba, REG_CONTROLLER_CAPABILITIES);
> +		mac = hba->capabilities & MASK_TRANSFER_REQUESTS_SLOTS_MCQ;
> +		mac++;

Can you add a comment to state that the MAC value is 0 based?

> +	} else {
> +		mac = hba->vops->get_hba_mac(hba);
> +	}
>  	if (mac < 0)
>  		goto err;
>  
> @@ -423,6 +426,11 @@ void ufshcd_mcq_enable(struct ufs_hba *hba)
>  }
>  EXPORT_SYMBOL_GPL(ufshcd_mcq_enable);
>  
> +void ufshcd_mcq_disable(struct ufs_hba *hba)
> +{
> +	ufshcd_rmwl(hba, MCQ_MODE_SELECT, 0, REG_UFS_MEM_CFG);
> +}
> +
>  void ufshcd_mcq_config_esi(struct ufs_hba *hba, struct msi_msg *msg)
>  {
>  	ufshcd_writel(hba, msg->address_lo, REG_UFS_ESILBA);
> diff --git a/drivers/ufs/core/ufshcd-priv.h b/drivers/ufs/core/ufshcd-priv.h
> index 88ce93748305..ce36154ce963 100644
> --- a/drivers/ufs/core/ufshcd-priv.h
> +++ b/drivers/ufs/core/ufshcd-priv.h
> @@ -64,6 +64,7 @@ void ufshcd_auto_hibern8_update(struct ufs_hba *hba, u32 ahit);
>  void ufshcd_compl_one_cqe(struct ufs_hba *hba, int task_tag,
>  			  struct cq_entry *cqe);
>  int ufshcd_mcq_init(struct ufs_hba *hba);
> +void ufshcd_mcq_disable(struct ufs_hba *hba);
>  int ufshcd_mcq_decide_queue_depth(struct ufs_hba *hba);
>  int ufshcd_mcq_memory_alloc(struct ufs_hba *hba);
>  struct ufs_hw_queue *ufshcd_mcq_req_to_hwq(struct ufs_hba *hba,
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index b3444f9ce130..9e0290c6c2d3 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -8753,13 +8753,15 @@ static int ufshcd_device_init(struct ufs_hba *hba, bool init_dev_params)
>  		if (ret)
>  			return ret;
>  		if (is_mcq_supported(hba) && !hba->scsi_host_added) {
> +			ufshcd_mcq_enable(hba);
> +			hba->mcq_enabled = true;

If the 'mcq_enabled' assignment goes hand in hand with
ufshcd_mcq_{enable/disable}, why shouldn't it be moved inside?

- Mani

>  			ret = ufshcd_alloc_mcq(hba);
>  			if (!ret) {
>  				ufshcd_config_mcq(hba);
> -				ufshcd_mcq_enable(hba);
> -				hba->mcq_enabled = true;
>  			} else {
>  				/* Continue with SDB mode */
> +				ufshcd_mcq_disable(hba);
> +				hba->mcq_enabled = false;
>  				use_mcq_mode = false;
>  				dev_err(hba->dev, "MCQ mode is disabled, err=%d\n",
>  					 ret);
> diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
> index c0e28a512b3c..6518997930f3 100644
> --- a/include/ufs/ufshcd.h
> +++ b/include/ufs/ufshcd.h
> @@ -325,7 +325,9 @@ struct ufs_pwr_mode_info {
>   * @event_notify: called to notify important events
>   * @reinit_notify: called to notify reinit of UFSHCD during max gear switch
>   * @mcq_config_resource: called to configure MCQ platform resources
> - * @get_hba_mac: called to get vendor specific mac value, mandatory for mcq mode
> + * @get_hba_mac: reports maximum number of outstanding commands supported by
> + *	the controller. Should be implemented for UFSHCI 4.0 or later
> + *	controllers that are not compliant with the UFSHCI 4.0 specification.
>   * @op_runtime_config: called to config Operation and runtime regs Pointers
>   * @get_outstanding_cqs: called to get outstanding completion queues
>   * @config_esi: called to config Event Specific Interrupt
> diff --git a/include/ufs/ufshci.h b/include/ufs/ufshci.h
> index 8d0cc73537c6..38fe97971a65 100644
> --- a/include/ufs/ufshci.h
> +++ b/include/ufs/ufshci.h
> @@ -68,6 +68,7 @@ enum {
>  /* Controller capability masks */
>  enum {
>  	MASK_TRANSFER_REQUESTS_SLOTS_SDB	= 0x0000001F,
> +	MASK_TRANSFER_REQUESTS_SLOTS_MCQ	= 0x000000FF,
>  	MASK_NUMBER_OUTSTANDING_RTT		= 0x0000FF00,
>  	MASK_TASK_MANAGEMENT_REQUEST_SLOTS	= 0x00070000,
>  	MASK_EHSLUTRD_SUPPORTED			= 0x00400000,

-- 
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