linux-kernel - Re: [PATCH v2] soc: qcom: Rework BCM_TCS

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Message-ID: <bb5d855954d5ff8694a3978a9f87a9d2.sboyd@kernel.org>
Date: Mon, 28 Oct 2024 10:56:41 -0700
From: Stephen Boyd <sboyd@...nel.org>
To: Eugen Hristev <eugen.hristev@...aro.org>, linux-arm-msm@...r.kernel.org
Cc: andersson@...nel.org, konradybcio@...nel.org, linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org, linux-pm@...r.kernel.org, djakov@...nel.org, mturquette@...libre.com, Eugen Hristev <eugen.hristev@...aro.org>
Subject: Re: [PATCH v2] soc: qcom: Rework BCM_TCS_CMD macro

Quoting Eugen Hristev (2024-10-28 09:34:03)
> diff --git a/include/soc/qcom/tcs.h b/include/soc/qcom/tcs.h
> index 3acca067c72b..152947a922c0 100644
> --- a/include/soc/qcom/tcs.h
> +++ b/include/soc/qcom/tcs.h
> @@ -60,22 +63,19 @@ struct tcs_request {
>         struct tcs_cmd *cmds;
>  };
>  
> -#define BCM_TCS_CMD_COMMIT_SHFT                30
> -#define BCM_TCS_CMD_COMMIT_MASK                0x40000000
> -#define BCM_TCS_CMD_VALID_SHFT         29
> -#define BCM_TCS_CMD_VALID_MASK         0x20000000
> -#define BCM_TCS_CMD_VOTE_X_SHFT                14
> -#define BCM_TCS_CMD_VOTE_MASK          0x3fff
> -#define BCM_TCS_CMD_VOTE_Y_SHFT                0
> -#define BCM_TCS_CMD_VOTE_Y_MASK                0xfffc000
> +#define BCM_TCS_CMD_COMMIT_MASK                BIT(30)
> +#define BCM_TCS_CMD_VALID_MASK         BIT(29)
> +#define BCM_TCS_CMD_VOTE_MASK          GENMASK(13, 0)
> +#define BCM_TCS_CMD_VOTE_Y_MASK                GENMASK(13, 0)
> +#define BCM_TCS_CMD_VOTE_X_MASK                GENMASK(27, 14)
>  
>  /* Construct a Bus Clock Manager (BCM) specific TCS command */
>  #define BCM_TCS_CMD(commit, valid, vote_x, vote_y)             \
> -       (((commit) << BCM_TCS_CMD_COMMIT_SHFT) |                \
> -       ((valid) << BCM_TCS_CMD_VALID_SHFT) |                   \
> -       ((cpu_to_le32(vote_x) &                                 \
> -       BCM_TCS_CMD_VOTE_MASK) << BCM_TCS_CMD_VOTE_X_SHFT) |    \
> -       ((cpu_to_le32(vote_y) &                                 \
> -       BCM_TCS_CMD_VOTE_MASK) << BCM_TCS_CMD_VOTE_Y_SHFT))
> +       (le32_encode_bits(commit, BCM_TCS_CMD_COMMIT_MASK) |    \
> +       le32_encode_bits(valid, BCM_TCS_CMD_VALID_MASK) |       \
> +       le32_encode_bits(vote_x,        \
> +                       BCM_TCS_CMD_VOTE_X_MASK) |              \
> +       le32_encode_bits(vote_y,        \
> +                       BCM_TCS_CMD_VOTE_Y_MASK))

Why is cpu_to_le32() inside BCM_TCS_CMD at all? Is struct tcs_cmd::data
supposed to be marked as __le32?

Can the whole u32 be constructed and turned into an __le32 after setting
all the bit fields instead of using le32_encode_bits() multiple times?