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

[Bjorn Andersson]

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.

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.

> 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.

> - * 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.

> -	{					\
> -		.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"?

> +		.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

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.

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
> -- 
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