linux-kernel - Re: [PATCH v10 4/6] soc: qcom: cpr: Move common functions to new file

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Date:   Sat, 3 Jun 2023 10:49:22 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        Niklas Cassel <nks@...wful.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     Robert Marko <robimarko@...il.com>, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-pm@...r.kernel.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>
Subject: Re: [PATCH v10 4/6] soc: qcom: cpr: Move common functions to new file



On 27.02.2023 04:09, Dmitry Baryshkov wrote:
> On 17/02/2023 13:08, Konrad Dybcio wrote:
>> From: AngeloGioacchino Del Regno <angelogioacchino.delregno@...ainline.org>
>>
>> In preparation for implementing a new driver that will be handling
>> CPRv3, CPRv4 and CPR-Hardened, format out common functions to a new
>> file.
>>
>> Update cpr_get_fuses in preparation for CPR3 implementation, change
>> parameters where necessary to not take cpr.c private data structures.
>>
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...ainline.org>
>> [Konrad: rebase, apply review comments, don't break backwards compat, improve msg]
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
>> ---
>>   drivers/soc/qcom/Makefile     |   2 +-
>>   drivers/soc/qcom/cpr-common.c | 363 +++++++++++++++++++++++++++++++++++++++
>>   drivers/soc/qcom/cpr-common.h | 108 ++++++++++++
>>   drivers/soc/qcom/cpr.c        | 386 +++---------------------------------------
>>   4 files changed, 494 insertions(+), 365 deletions(-)
>>
> 
> [skipped]
> 
>> diff --git a/drivers/soc/qcom/cpr-common.h b/drivers/soc/qcom/cpr-common.h
>> new file mode 100644
>> index 000000000000..2cd15f7eac90
>> --- /dev/null
>> +++ b/drivers/soc/qcom/cpr-common.h
>> @@ -0,0 +1,108 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_opp.h>
>> +#include <linux/regulator/consumer.h>
>> +
>> +enum voltage_change_dir {
>> +    NO_CHANGE,
>> +    DOWN,
>> +    UP,
>> +};
>> +
>> +struct fuse_corner_data {
>> +    int ref_uV;
>> +    int max_uV;
>> +    int min_uV;
>> +    int range_uV;
>> +    /* fuse volt: closed/open loop */
>> +    int volt_cloop_adjust;
>> +    int volt_oloop_adjust;
> 
> For CPR3 these values are per-fusing-rev.
> (for 8996 tables list per-fusing-rev values for min_uV, volt_cloop_adjust and volt_oloop_adjust)
Yes they are per-fuse-rev on other SoCs as well.. Angelo didn't implement
this in the original revision of the driver and I think it'd be good to
add it incrementally since we already consume the necessary fuse..
Otherwise -ETOOFAT!


> 
> Another option, of course, might be to have a per-SoC code that uses fusing_rev to update the fuse_corner_data, but it would mean making it non-const.
Hm.. a const array sounds better to me..

> 
>> +    int max_volt_scale;
>> +    int max_quot_scale;
> 
> Any reason for these limitations?
I'd assume that's a safety feature Qualcomm implemented to avoid
burning chips if cosmic rays poke at DRAM or some chips are fused
incorrectly.. Preferably, I'd keep it!

> 
>> +    /* fuse quot */
>> +    int quot_offset;
>> +    int quot_scale;
>> +    int quot_adjust;
> 
> I see that quot_offset/quot_scale/quot_adjust are set to 0/1/0 for all the platforms I can assess at this moment (8996/8998/sdm660). Can we drop them? If we need them later, we can readd them later.
I was about to do it, but noticed 8956 sets scaling to 10..
Guess we can leave it since it's already there!

Konrad
> 
>> +    /* fuse quot_offset */
>> +    int quot_offset_scale;
>> +    int quot_offset_adjust;
>> +};
>> +
>> +struct cpr_fuse {
>> +    char *ring_osc;
>> +    char *init_voltage;
>> +    char *quotient;
>> +    char *quotient_offset;
>> +};
>> +
>> +struct fuse_corner {
>> +    int min_uV;
>> +    int max_uV;
>> +    int uV;
>> +    int quot;
>> +    int step_quot;
>> +    const struct reg_sequence *accs;
>> +    int num_accs;
>> +    unsigned long max_freq;
>> +    u8 ring_osc_idx;
>> +};
>> +
>> +struct corner {
>> +    int min_uV;
>> +    int max_uV;
>> +    int uV;
>> +    int last_uV;
>> +    int quot_adjust;
>> +    u32 save_ctl;
>> +    u32 save_irq;
>> +    unsigned long freq;
>> +    bool is_open_loop;
>> +    struct fuse_corner *fuse_corner;
>> +};
>> +
>> +struct corner_data {
>> +    unsigned int fuse_corner;
>> +    unsigned long freq;
>> +};
>> +
>> +struct acc_desc {
>> +    unsigned int    enable_reg;
>> +    u32        enable_mask;
>> +
>> +    struct reg_sequence    *config;
>> +    struct reg_sequence    *settings;
>> +    int            num_regs_per_fuse;
>> +};
>> +
>> +struct cpr_acc_desc {
>> +    const struct cpr_desc *cpr_desc;
>> +    const struct acc_desc *acc_desc;
>> +};
>> +
> 
> [skipped the rest]
>