Re: [PATCH v4 07/16] ufs: core: mcq: Calculate queue depth

[Bart Van Assche <bvanassche@acm.org>]

On 11/9/22 11:41, Asutosh Das wrote:
> +int ufshcd_mcq_decide_queue_depth(struct ufs_hba *hba)
> +{
> +	int mac;
> +
> +	/* Mandatory to implement get_hba_mac() */
> +	mac = ufshcd_mcq_vops_get_hba_mac(hba);
> +	if (mac < 0) {
> +		dev_err(hba->dev, "Failed to get mac, err=%d\n", mac);
> +		return mac;
> +	}
> +
> +	/*  MAC is a 0 based value. */
> +	mac += 1;

Please make ufshcd_mcq_vops_get_hba_mac() return a 1-based value. The 
0-based convention is useful for bit-constrained device registers but is 
confusing when not reading from a hardware register.

> +	/*
> +	 * max. value of bqueuedepth = 256, mac is host dependent.
> +	 * It is mandatory for UFS device to define bQueueDepth if
> +	 * shared queuing architecture is enabled.
> +	 */
> +	return min_t(int, mac, hba->dev_info.bqueuedepth);

According to the UFS specification bQueueDepth is zero if there is one 
queue per logical unit inside the device. Should a warning statement be 
added that reports a complaint if bQueueDepth == 0 since the above code 
does not support bQueueDepth == 0? I'm not sure whether any UFS devices 
exist that use per-LU queuing.

> +static int ufs_qcom_get_hba_mac(struct ufs_hba *hba)
> +{
> +	/* Default is 32, but Qualcomm HC supports upto 64 */

I think that "default is 32" should be left out since the code that 
reads the MAC register has been removed.

Additionally, please change "upto" into "up to".

Thanks,

Bart.