Re: [PATCH v2 05/17] ufs: core: mcq: Introduce Multi Circular Queue

Eddie Huang
2022-10-18T05:29:34Z

Hi Asutosh,

On Wed, 2022-10-05 at 18:06 -0700, Asutosh Das wrote:
> Introduce multi-circular queue (MCQ) which has been added
> in UFSHC v4.0 standard in addition to the Single Doorbell mode.
> The MCQ mode supports multiple submission and completion queues.
> Add support to configure the number of queues.
>
> Co-developed-by: Can Guo <quic_cang@quicinc.com>
> Signed-off-by: Can Guo <quic_cang@quicinc.com>
> Signed-off-by: Asutosh Das <quic_asutoshd@quicinc.com>
> ---
> drivers/ufs/core/Makefile | 2 +-
> drivers/ufs/core/ufs-mcq.c | 113
> +++++++++++++++++++++++++++++++++++++++++
> drivers/ufs/core/ufshcd-priv.h | 1 +
> drivers/ufs/core/ufshcd.c | 12 +++++
> include/ufs/ufshcd.h | 4 ++
> 5 files changed, 131 insertions(+), 1 deletion(-)
> create mode 100644 drivers/ufs/core/ufs-mcq.c
>

[...]

> /**
> * ufshcd_probe_hba - probe hba to detect device and initialize it
> * @hba: per-adapter instance
> @@ -8224,6 +8233,9 @@ static int ufshcd_probe_hba(struct ufs_hba
> *hba, bool init_dev_params)
> goto out;
>
> if (is_mcq_supported(hba)) {
> + ret = ufshcd_config_mcq(hba);
> + if (ret)
> + goto out;
> ret = scsi_add_host(host, hba->dev);
> if (ret) {
> dev_err(hba->dev, "scsi_add_host
> failed\n");
>

ufshcd_probe_hba() may be called multiple times (from
ufshcd_async_scan() and ufshcd_host_reset_and_restore()). It is not a
good idea to allocate memory in ufshcd_config_mcq(). Although use
parameter init_dev_params to decide call ufshcd_config_mcq() or not, it
may cause ufshcd_host_reset_and_restore() not to configure MCQ (init
SQ/CQ ptr...) again.

Suggest to separate configure MCQ (set hardware register) and allocate
memory to different function

Thanks,
Eddie Huang