linux-kernel - Re: [PATCH 3/9] clk: qcom: gcc-msm8998: Control MMSS and GPUSS GPLL0 outputs properly

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Message-ID: <18f508e7-8a7e-162b-4bed-eaef45147a22@linaro.org>
Date:   Thu, 22 Jun 2023 17:05:28 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Jeffrey Hugo <quic_jhugo@...cinc.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.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>,
        Taniya Das <tdas@...eaurora.org>
Cc:     Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Jami Kettunen <jami.kettunen@...ainline.org>
Subject: Re: [PATCH 3/9] clk: qcom: gcc-msm8998: Control MMSS and GPUSS GPLL0
 outputs properly

On 22.06.2023 16:55, Jeffrey Hugo wrote:
> On 6/22/2023 5:57 AM, Konrad Dybcio wrote:
>> Up until now, we've been relying on some non-descript hardware magic
>> to pinkypromise turn the clocks on for us. While new SoCs shine with
>> that feature, MSM8998 can not always be fully trusted.
>>
>> Register the MMSS and GPUSS GPLL0 legs with the CCF to allow for manual
>> enable voting.
>>
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
>> ---
>>   drivers/clk/qcom/gcc-msm8998.c | 58 ++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 58 insertions(+)
>>
>> diff --git a/drivers/clk/qcom/gcc-msm8998.c b/drivers/clk/qcom/gcc-msm8998.c
>> index be024f8093c5..cccb19cae481 100644
>> --- a/drivers/clk/qcom/gcc-msm8998.c
>> +++ b/drivers/clk/qcom/gcc-msm8998.c
>> @@ -25,6 +25,9 @@
>>   #include "reset.h"
>>   #include "gdsc.h"
>>   +#define GCC_MMSS_MISC    0x0902C
>> +#define GCC_GPU_MISC    0x71028
>> +
>>   static struct pll_vco fabia_vco[] = {
>>       { 250000000, 2000000000, 0 },
>>       { 125000000, 1000000000, 1 },
>> @@ -1367,6 +1370,22 @@ static struct clk_branch gcc_boot_rom_ahb_clk = {
>>       },
>>   };
>>   +static struct clk_branch gcc_mmss_gpll0_div_clk = {
>> +    .halt_check = BRANCH_HALT_DELAY,
>> +    .clkr = {
>> +        .enable_reg = 0x5200c,
>> +        .enable_mask = BIT(0),
>> +        .hw.init = &(struct clk_init_data){
>> +            .name = "gcc_mmss_gpll0_div_clk",
>> +            .parent_hws = (const struct clk_hw *[]) {
>> +                &gpll0_out_main.clkr.hw,
>> +            },
>> +            .num_parents = 1,
>> +            .ops = &clk_branch2_ops,
>> +        },
>> +    },
>> +};
>> +
>>   static struct clk_branch gcc_mmss_gpll0_clk = {
>>       .halt_check = BRANCH_HALT_DELAY,
>>       .clkr = {
>> @@ -1395,6 +1414,38 @@ static struct clk_branch gcc_mss_gpll0_div_clk_src = {
>>       },
>>   };
>>   +static struct clk_branch gcc_gpu_gpll0_div_clk = {
>> +    .halt_check = BRANCH_HALT_DELAY,
>> +    .clkr = {
>> +        .enable_reg = 0x5200c,
>> +        .enable_mask = BIT(3),
>> +        .hw.init = &(struct clk_init_data){
>> +            .name = "gcc_gpu_gpll0_div_clk",
>> +            .parent_hws = (const struct clk_hw *[]) {
>> +                &gpll0_out_main.clkr.hw,
>> +            },
>> +            .num_parents = 1,
>> +            .ops = &clk_branch2_ops,
>> +        },
>> +    },
>> +};
>> +
>> +static struct clk_branch gcc_gpu_gpll0_clk = {
>> +    .halt_check = BRANCH_HALT_DELAY,
>> +    .clkr = {
>> +        .enable_reg = 0x5200c,
>> +        .enable_mask = BIT(4),
>> +        .hw.init = &(struct clk_init_data){
>> +            .name = "gcc_gpu_gpll0_clk",
>> +            .parent_hws = (const struct clk_hw *[]) {
>> +                &gpll0_out_main.clkr.hw,
>> +            },
>> +            .num_parents = 1,
>> +            .ops = &clk_branch2_ops,
>> +        },
>> +    },
>> +};
>> +
>>   static struct clk_branch gcc_blsp1_ahb_clk = {
>>       .halt_reg = 0x17004,
>>       .halt_check = BRANCH_HALT_VOTED,
>> @@ -3080,6 +3131,9 @@ static struct clk_regmap *gcc_msm8998_clocks[] = {
>>       [AGGRE2_SNOC_NORTH_AXI] = &aggre2_snoc_north_axi_clk.clkr,
>>       [SSC_XO] = &ssc_xo_clk.clkr,
>>       [SSC_CNOC_AHBS_CLK] = &ssc_cnoc_ahbs_clk.clkr,
>> +    [GCC_MMSS_GPLL0_DIV_CLK] = &gcc_mmss_gpll0_div_clk.clkr,
>> +    [GCC_GPU_GPLL0_DIV_CLK] = &gcc_gpu_gpll0_div_clk.clkr,
>> +    [GCC_GPU_GPLL0_CLK] = &gcc_gpu_gpll0_clk.clkr,
>>   };
>>     static struct gdsc *gcc_msm8998_gdscs[] = {
>> @@ -3235,6 +3289,10 @@ static int gcc_msm8998_probe(struct platform_device *pdev)
>>       if (ret)
>>           return ret;
>>   +    /* Disable the GPLL0 active input to MMSS and GPU via MISC registers */
>> +    regmap_write(regmap, GCC_MMSS_MISC, 0x10003);
>> +    regmap_write(regmap, GCC_GPU_MISC, 0x10003);
> 
> I wonder, does this disrupt a handoff of an active display from the bootloader to Linux?
My phone's bootloader doesn't initialize the display, if you (or Angelo
or Jami, +CC) could test this, it'd be wonderful.

Konrad