Re: [PATCH v4 07/16] ufs: core: mcq: Calculate queue depth
From: Bart Van Assche
Date: Wed Nov 09 2022 - 16:28:55 EST
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.