linux-kernel - Re: [PATCH V3 2/4] clk: qcom: branch: Add mem ops support for branch2 clocks

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Date:   Mon, 6 Nov 2023 15:00:23 +0200
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Imran Shaik <quic_imrashai@...cinc.com>
Cc:     Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Taniya Das <quic_tdas@...cinc.com>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Ajit Pandey <quic_ajipan@...cinc.com>,
        Jagadeesh Kona <quic_jkona@...cinc.com>
Subject: Re: [PATCH V3 2/4] clk: qcom: branch: Add mem ops support for branch2 clocks

On Mon, 6 Nov 2023 at 12:31, Imran Shaik <quic_imrashai@...cinc.com> wrote:
>
> From: Taniya Das <quic_tdas@...cinc.com>
>
> Clock CBCRs with memories need an update for memory before enable/disable
> of the clock, which helps retain the respective block's register contents.
> Add support for the mem ops to handle this sequence.
>
> Signed-off-by: Taniya Das <quic_tdas@...cinc.com>
> Signed-off-by: Imran Shaik <quic_imrashai@...cinc.com>

It would be nice to have a description of what is 'CBCR with memories'
and how does it differ from CBCR_FORCE_MEM_CORE_ON?

> ---
>  drivers/clk/qcom/clk-branch.c | 39 +++++++++++++++++++++++++++++++++++
>  drivers/clk/qcom/clk-branch.h | 21 +++++++++++++++++++
>  2 files changed, 60 insertions(+)
>
> diff --git a/drivers/clk/qcom/clk-branch.c b/drivers/clk/qcom/clk-branch.c
> index fc4735f74f0f..61bdd2147bed 100644
> --- a/drivers/clk/qcom/clk-branch.c
> +++ b/drivers/clk/qcom/clk-branch.c
> @@ -1,6 +1,7 @@
>  // SPDX-License-Identifier: GPL-2.0
>  /*
>   * Copyright (c) 2013, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights reserved.
>   */
>
>  #include <linux/kernel.h>
> @@ -134,6 +135,44 @@ static void clk_branch2_disable(struct clk_hw *hw)
>         clk_branch_toggle(hw, false, clk_branch2_check_halt);
>  }
>
> +static int clk_branch2_mem_enable(struct clk_hw *hw)
> +{
> +       struct clk_mem_branch *mem_br = to_clk_mem_branch(hw);
> +       struct clk_branch branch = mem_br->branch;
> +       const char *name = clk_hw_get_name(&branch.clkr.hw);
> +       u32 val;
> +       int ret;
> +
> +       regmap_update_bits(branch.clkr.regmap, mem_br->mem_enable_reg,
> +                       mem_br->mem_enable_ack_mask, mem_br->mem_enable_ack_mask);
> +
> +       ret = regmap_read_poll_timeout(branch.clkr.regmap, mem_br->mem_ack_reg,
> +                       val, val & mem_br->mem_enable_ack_mask, 0, 200);
> +       if (ret) {
> +               WARN(1, "%s mem enable failed\n", name);
> +               return ret;
> +       }
> +
> +       return clk_branch2_enable(hw);
> +}
> +
> +static void clk_branch2_mem_disable(struct clk_hw *hw)
> +{
> +       struct clk_mem_branch *mem_br = to_clk_mem_branch(hw);
> +
> +       regmap_update_bits(mem_br->branch.clkr.regmap, mem_br->mem_enable_reg,
> +                                               mem_br->mem_enable_ack_mask, 0);
> +
> +       return clk_branch2_disable(hw);
> +}
> +
> +const struct clk_ops clk_branch2_mem_ops = {
> +       .enable = clk_branch2_mem_enable,
> +       .disable = clk_branch2_mem_disable,
> +       .is_enabled = clk_is_enabled_regmap,
> +};
> +EXPORT_SYMBOL_GPL(clk_branch2_mem_ops);
> +
>  const struct clk_ops clk_branch2_ops = {
>         .enable = clk_branch2_enable,
>         .disable = clk_branch2_disable,
> diff --git a/drivers/clk/qcom/clk-branch.h b/drivers/clk/qcom/clk-branch.h
> index 0cf800b9d08d..8ffed603c050 100644
> --- a/drivers/clk/qcom/clk-branch.h
> +++ b/drivers/clk/qcom/clk-branch.h
> @@ -38,6 +38,23 @@ struct clk_branch {
>         struct clk_regmap clkr;
>  };
>
> +/**
> + * struct clk_mem_branch - gating clock which are associated with memories
> + *
> + * @mem_enable_reg: branch clock memory gating register
> + * @mem_ack_reg: branch clock memory ack register
> + * @mem_enable_ack_mask: branch clock memory enable and ack field in @mem_ack_reg
> + * @branch: branch clock gating handle
> + *
> + * Clock which can gate its memories.
> + */
> +struct clk_mem_branch {
> +       u32     mem_enable_reg;
> +       u32     mem_ack_reg;
> +       u32     mem_enable_ack_mask;
> +       struct clk_branch branch;
> +};
> +
>  /* Branch clock common bits for HLOS-owned clocks */
>  #define CBCR_CLK_OFF                   BIT(31)
>  #define CBCR_NOC_FSM_STATUS            GENMASK(30, 28)
> @@ -85,8 +102,12 @@ extern const struct clk_ops clk_branch_ops;
>  extern const struct clk_ops clk_branch2_ops;
>  extern const struct clk_ops clk_branch_simple_ops;
>  extern const struct clk_ops clk_branch2_aon_ops;
> +extern const struct clk_ops clk_branch2_mem_ops;
>
>  #define to_clk_branch(_hw) \
>         container_of(to_clk_regmap(_hw), struct clk_branch, clkr)
>
> +#define to_clk_mem_branch(_hw) \
> +       container_of(to_clk_branch(_hw), struct clk_mem_branch, branch)
> +
>  #endif
> --
> 2.25.1
>


-- 
With best wishes
Dmitry