2023-09-05 16:04:32

by Bjorn Andersson

[permalink] [raw]
Subject: Re: [PATCH V6 6/6] scsi: ufs: qcom: Configure clk HW division based on scaling conditions.

On Fri, Sep 01, 2023 at 05:13:36PM +0530, Nitin Rawat wrote:
> a) Enable internal HW division of unipro core_clk for scale up condition.
> b) Clear internal HW division of unipro core_clk for scale down condition.
>

This commit message isn't good.

> Co-developed-by: Naveen Kumar Goud Arepalli <[email protected]>
> Signed-off-by: Naveen Kumar Goud Arepalli <[email protected]>
> Signed-off-by: Nitin Rawat <[email protected]>
> ---
> drivers/ufs/host/ufs-qcom.c | 31 +++++++++++++++++--------------
> drivers/ufs/host/ufs-qcom.h | 2 +-
> 2 files changed, 18 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index c251c98a74f0..2ddda9356abc 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -1389,18 +1389,21 @@ static int ufs_qcom_set_core_clk_ctrl(struct ufs_hba *hba,
> core_clk_ctrl_reg |= FIELD_PREP(CLK_1US_CYCLES_MASK, cycles_in_1us);
> }
>
> - /* Clear CORE_CLK_DIV_EN */
> - core_clk_ctrl_reg &= ~DME_VS_CORE_CLK_CTRL_CORE_CLK_DIV_EN_BIT;
> + /* Enable CORE_CLK_DIV_EN for scale up condition */
> + if (is_max_freq)
> + core_clk_ctrl_reg |= CORE_CLK_DIV_EN_BIT;
>
> ret = ufshcd_dme_set(hba,
> UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL),
> core_clk_ctrl_reg);
> + if (ret)
> + return ret;

Nice, but don't mix logical and stylistic changes in the same patch.

> /*
> * UFS host controller V4.0.0 onwards needs to program
> * PA_VS_CORE_CLK_40NS_CYCLES attribute per programmed
> * frequency of unipro core clk of UFS host controller.
> */
> - if (!ret && (host->hw_ver.major >= 4)) {
> + if (host->hw_ver.major >= 4) {
> if (cycles_in_40ns > PA_VS_CORE_CLK_40NS_CYCLES_MASK)
> return -EINVAL;
>
> @@ -1451,26 +1454,26 @@ static int ufs_qcom_clk_scale_up_post_change(struct ufs_hba *hba)
> static int ufs_qcom_clk_scale_down_pre_change(struct ufs_hba *hba)
> {
> struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> - int err;
> - u32 core_clk_ctrl_reg;
> + int ret;
> + u32 reg;

This just obfuscates the logical changes you're making.


Frankly, I've been staring at this for several minutes now. The commit
message says there is a change here (but fails to describe what problem
is solves or what the change is)...but I can't find the change!

Regards,
Bjorn

>
> if (!ufs_qcom_cap_qunipro(host))
> return 0;
>
> - err = ufshcd_dme_get(hba,
> + ret = ufshcd_dme_get(hba,
> UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL),
> - &core_clk_ctrl_reg);
> + &reg);
> + if (ret)
> + return ret;
>
> /* make sure CORE_CLK_DIV_EN is cleared */
> - if (!err &&
> - (core_clk_ctrl_reg & DME_VS_CORE_CLK_CTRL_CORE_CLK_DIV_EN_BIT)) {
> - core_clk_ctrl_reg &= ~DME_VS_CORE_CLK_CTRL_CORE_CLK_DIV_EN_BIT;
> - err = ufshcd_dme_set(hba,
> + if (reg & CORE_CLK_DIV_EN_BIT) {
> + reg &= ~CORE_CLK_DIV_EN_BIT;
> + ret = ufshcd_dme_set(hba,
> UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL),
> - core_clk_ctrl_reg);
> + reg);
> }
> -
> - return err;
> + return ret;
> }
>
> static int ufs_qcom_clk_scale_down_post_change(struct ufs_hba *hba)
> diff --git a/drivers/ufs/host/ufs-qcom.h b/drivers/ufs/host/ufs-qcom.h
> index bc176ef58e3e..bf0c370c79c7 100644
> --- a/drivers/ufs/host/ufs-qcom.h
> +++ b/drivers/ufs/host/ufs-qcom.h
> @@ -141,7 +141,7 @@ enum {
> /* bit and mask definitions for DME_VS_CORE_CLK_CTRL attribute */
> #define CLK_1US_CYCLES_MASK_V4 GENMASK(27, 16)
> #define CLK_1US_CYCLES_MASK GENMASK(7, 0)
> -#define DME_VS_CORE_CLK_CTRL_CORE_CLK_DIV_EN_BIT BIT(8)
> +#define CORE_CLK_DIV_EN_BIT BIT(8)
> #define PA_VS_CORE_CLK_40NS_CYCLES 0x9007
> #define PA_VS_CORE_CLK_40NS_CYCLES_MASK GENMASK(6, 0)
>
> --
> 2.17.1
>