Re: [PATCH 2/2] soc: qcom: llcc-plat: Make the driver more generic

[Vivek Gautam]

Hi Bjorn,


Thanks for the review.

On Thu, Jul 11, 2019 at 9:29 PM Bjorn Andersson
<bjorn.andersson@xxxxxxxxxx> wrote:
>
> On Thu 11 Jul 04:03 PDT 2019, Vivek Gautam wrote:
>
> > - Remove 'sdm845' from names, and use 'plat' instead.
> > - Move SCT_ENTRY macro to header file.
> > - Create a new config structure to asssign to of-match-data.
> >
>
> I interpret the intention of these two patches as that you want to add
> some new platform without having to create one llcc-xyz.c per platform.

That's right. The intention is to avoid creating a new platform specific file.

>
> If that's the case then the only user of this macro would be in plat.c,
> so I don't see a reason for moving it to the header file.

Alright. Better to keep it in the driver file itself.

>
> > Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx>
> > ---
> >  drivers/soc/qcom/llcc-plat.c       | 77 ++++++++++++--------------------------
> >  include/linux/soc/qcom/llcc-qcom.h | 45 ++++++++++++++++++++++
> >  2 files changed, 68 insertions(+), 54 deletions(-)
> >
> > diff --git a/drivers/soc/qcom/llcc-plat.c b/drivers/soc/qcom/llcc-plat.c
> > index 86600d97c36d..31cff0f75b53 100644
> > --- a/drivers/soc/qcom/llcc-plat.c
> > +++ b/drivers/soc/qcom/llcc-plat.c
> > @@ -1,6 +1,6 @@
> >  // SPDX-License-Identifier: GPL-2.0
> >  /*
> > - * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
> > + * Copyright (c) 2017-2019, The Linux Foundation. All rights reserved.
> >   *
> >   */
> >
> > @@ -10,47 +10,7 @@
> >  #include <linux/of_device.h>
> >  #include <linux/soc/qcom/llcc-qcom.h>
> >
> > -/*
> > - * SCT(System Cache Table) entry contains of the following members:
>
> Should have caught this during previous review, but this comment simply
> duplicates the kerneldoc for struct llcc_slice_config.

Ok, i noticed it now. Will clean it up. I can remove this comment, and update
the one for struct llcc_slice_config.

>
> > - * usecase_id: Unique id for the client's use case
> > - * slice_id: llcc slice id for each client
> > - * max_cap: The maximum capacity of the cache slice provided in KB
> > - * priority: Priority of the client used to select victim line for replacement
> > - * fixed_size: Boolean indicating if the slice has a fixed capacity
> > - * bonus_ways: Bonus ways are additional ways to be used for any slice,
> > - *           if client ends up using more than reserved cache ways. Bonus
> > - *           ways are allocated only if they are not reserved for some
> > - *           other client.
> > - * res_ways: Reserved ways for the cache slice, the reserved ways cannot
> > - *           be used by any other client than the one its assigned to.
> > - * cache_mode: Each slice operates as a cache, this controls the mode of the
> > - *             slice: normal or TCM(Tightly Coupled Memory)
> > - * probe_target_ways: Determines what ways to probe for access hit. When
> > - *                    configured to 1 only bonus and reserved ways are probed.
> > - *                    When configured to 0 all ways in llcc are probed.
> > - * dis_cap_alloc: Disable capacity based allocation for a client
> > - * retain_on_pc: If this bit is set and client has maintained active vote
> > - *               then the ways assigned to this client are not flushed on power
> > - *               collapse.
> > - * activate_on_init: Activate the slice immediately after the SCT is programmed
> > - */
> > -#define SCT_ENTRY(uid, sid, mc, p, fs, bway, rway, cmod, ptw, dca, rp, a) \
>
> This simply maps macro arguments 1:1 to struct members, there's no need
> for a macro for this.

Sure, will remove the macro.

>
> > -     {                                       \
> > -             .usecase_id = uid,              \
> > -             .slice_id = sid,                \
> > -             .max_cap = mc,                  \
> > -             .priority = p,                  \
> > -             .fixed_size = fs,               \
> > -             .bonus_ways = bway,             \
> > -             .res_ways = rway,               \
> > -             .cache_mode = cmod,             \
> > -             .probe_target_ways = ptw,       \
> > -             .dis_cap_alloc = dca,           \
> > -             .retain_on_pc = rp,             \
> > -             .activate_on_init = a,          \
> > -     }
> > -
> > -static struct llcc_slice_config sdm845_data[] =  {
> > +static const struct llcc_slice_config sdm845_data[] =  {
> >       SCT_ENTRY(LLCC_CPUSS,    1,  2816, 1, 0, 0xffc, 0x2,   0, 0, 1, 1, 1),
> >       SCT_ENTRY(LLCC_VIDSC0,   2,  512,  2, 1, 0x0,   0x0f0, 0, 0, 1, 1, 0),
> >       SCT_ENTRY(LLCC_VIDSC1,   3,  512,  2, 1, 0x0,   0x0f0, 0, 0, 1, 1, 0),
> > @@ -71,30 +31,39 @@ static struct llcc_slice_config sdm845_data[] =  {
> >       SCT_ENTRY(LLCC_AUDHW,    22, 1024, 1, 1, 0xffc, 0x2,   0, 0, 1, 1, 0),
> >  };
> >
> > -static int sdm845_qcom_llcc_remove(struct platform_device *pdev)
> > +static const struct qcom_llcc_config sdm845_cfg = {
> > +     .sct_data       = sdm845_data,
> > +     .size           = ARRAY_SIZE(sdm845_data),
> > +};
> > +
> > +static int qcom_plat_llcc_remove(struct platform_device *pdev)
> >  {
> >       return qcom_llcc_remove(pdev);
> >  }
> >
> > -static int sdm845_qcom_llcc_probe(struct platform_device *pdev)
> > +static int qcom_plat_llcc_probe(struct platform_device *pdev)
> >  {
> > -     return qcom_llcc_probe(pdev, sdm845_data, ARRAY_SIZE(sdm845_data));
> > +     const struct qcom_llcc_config *cfg;
> > +
> > +     cfg = of_device_get_match_data(&pdev->dev);
> > +
> > +     return qcom_llcc_probe(pdev, cfg->sct_data, cfg->size);
> >  }
> >
> > -static const struct of_device_id sdm845_qcom_llcc_of_match[] = {
> > -     { .compatible = "qcom,sdm845-llcc", },
> > +static const struct of_device_id qcom_plat_llcc_of_match[] = {
> > +     { .compatible = "qcom,sdm845-llcc", .data = &sdm845_cfg },
> >       { }
> >  };
> >
> > -static struct platform_driver sdm845_qcom_llcc_driver = {
> > +static struct platform_driver qcom_plat_llcc_driver = {
> >       .driver = {
> > -             .name = "sdm845-llcc",
> > -             .of_match_table = sdm845_qcom_llcc_of_match,
> > +             .name = "qcom-plat-llcc",
>
> With this being the "one and only llcc driver", why not making it
> "qcom_llcc"?

Sure, will make it just "qcom_llcc" driver.

>
> > +             .of_match_table = qcom_plat_llcc_of_match,
> >       },
> > -     .probe = sdm845_qcom_llcc_probe,
> > -     .remove = sdm845_qcom_llcc_remove,
> > +     .probe = qcom_plat_llcc_probe,
> > +     .remove = qcom_plat_llcc_remove,
> >  };
> > -module_platform_driver(sdm845_qcom_llcc_driver);
> > +module_platform_driver(qcom_plat_llcc_driver);
> >
> > -MODULE_DESCRIPTION("QCOM sdm845 LLCC driver");
> > +MODULE_DESCRIPTION("QCOM platform LLCC driver");
> >  MODULE_LICENSE("GPL v2");
> > diff --git a/include/linux/soc/qcom/llcc-qcom.h b/include/linux/soc/qcom/llcc-qcom.h
>
> This file should be describing the public interface to the llcc, the
> private pieces is better kept in drivers/soc/qcom/llcc.h

Yes. I will split the things in two separate files as suggested.

>
> But this patch makes me wonder if there's a need to split llcc-slice and
> llcc-plat (and have a header file to describe API between them) instead
> of just having one file.

Nice opportunity to merge the two files? :)

Best regards
Vivek
>
> Regards,
> Bjorn
>
> > index eb71a50b8afc..8776bb5d3891 100644
> > --- a/include/linux/soc/qcom/llcc-qcom.h
> > +++ b/include/linux/soc/qcom/llcc-qcom.h
> > @@ -27,6 +27,46 @@
> >  #define LLCC_MDMPNG      21
> >  #define LLCC_AUDHW       22
> >
> > +/*
> > + * SCT(System Cache Table) entry contains of the following members:
> > + * usecase_id: Unique id for the client's use case
> > + * slice_id: llcc slice id for each client
> > + * max_cap: The maximum capacity of the cache slice provided in KB
> > + * priority: Priority of the client used to select victim line for replacement
> > + * fixed_size: Boolean indicating if the slice has a fixed capacity
> > + * bonus_ways: Bonus ways are additional ways to be used for any slice,
> > + *           if client ends up using more than reserved cache ways. Bonus
> > + *           ways are allocated only if they are not reserved for some
> > + *           other client.
> > + * res_ways: Reserved ways for the cache slice, the reserved ways cannot
> > + *           be used by any other client than the one its assigned to.
> > + * cache_mode: Each slice operates as a cache, this controls the mode of the
> > + *             slice: normal or TCM(Tightly Coupled Memory)
> > + * probe_target_ways: Determines what ways to probe for access hit. When
> > + *                    configured to 1 only bonus and reserved ways are probed.
> > + *                    When configured to 0 all ways in llcc are probed.
> > + * dis_cap_alloc: Disable capacity based allocation for a client
> > + * retain_on_pc: If this bit is set and client has maintained active vote
> > + *               then the ways assigned to this client are not flushed on power
> > + *               collapse.
> > + * activate_on_init: Activate the slice immediately after the SCT is programmed
> > + */
> > +#define SCT_ENTRY(uid, sid, mc, p, fs, bway, rway, cmod, ptw, dca, rp, a) \
> > +     {                                       \
> > +             .usecase_id = uid,              \
> > +             .slice_id = sid,                \
> > +             .max_cap = mc,                  \
> > +             .priority = p,                  \
> > +             .fixed_size = fs,               \
> > +             .bonus_ways = bway,             \
> > +             .res_ways = rway,               \
> > +             .cache_mode = cmod,             \
> > +             .probe_target_ways = ptw,       \
> > +             .dis_cap_alloc = dca,           \
> > +             .retain_on_pc = rp,             \
> > +             .activate_on_init = a,          \
> > +     }
> > +
> >  /**
> >   * llcc_slice_desc - Cache slice descriptor
> >   * @slice_id: llcc slice id
> > @@ -67,6 +107,11 @@ struct llcc_slice_config {
> >       bool activate_on_init;
> >  };
> >
> > +struct qcom_llcc_config {
> > +     const struct llcc_slice_config *sct_data;
> > +     int size;
> > +};
> > +
> >  /**
> >   * llcc_drv_data - Data associated with the llcc driver
> >   * @regmap: regmap associated with the llcc device
> > --
> > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> > of Code Aurora Forum, hosted by The Linux Foundation
> >



--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation