Re: [PATCH v3 4/6] interconnect: qcom: Consolidate interconnect RPMh support

[Georgi Djakov <georgi.djakov@linaro.org>]

Hi Sibi,

Thank you for refreshing this patchset!

On 2/9/20 20:34, Sibi Sankar wrote:
> From: David Dai <daidavid1@codeaurora.org>
> 
> Add bcm voter driver and add support for RPMh specific interconnect
> providers which implements the set and aggregate functionalities that
> translates bandwidth requests into RPMh messages. These modules provide
> a common set of functionalities for all Qualcomm RPMh based interconnect
> providers and should help reduce code duplication when adding new
> providers.
> 
> Signed-off-by: David Dai <daidavid1@codeaurora.org>
> Signed-off-by: Odelu Kukatla <okukatla@codeaurora.org>
> Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
> ---
>  drivers/interconnect/qcom/Kconfig     |  13 +-
>  drivers/interconnect/qcom/Makefile    |   4 +
>  drivers/interconnect/qcom/bcm-voter.c | 366 ++++++++++++++++++++++++++
>  drivers/interconnect/qcom/bcm-voter.h |  27 ++
>  drivers/interconnect/qcom/icc-rpmh.c  | 147 +++++++++++
>  drivers/interconnect/qcom/icc-rpmh.h  | 149 +++++++++++
>  6 files changed, 705 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/interconnect/qcom/bcm-voter.c
>  create mode 100644 drivers/interconnect/qcom/bcm-voter.h
>  create mode 100644 drivers/interconnect/qcom/icc-rpmh.c
>  create mode 100644 drivers/interconnect/qcom/icc-rpmh.h
> 
> diff --git a/drivers/interconnect/qcom/Kconfig b/drivers/interconnect/qcom/Kconfig
> index 76938ece1658e..08cfd676b4299 100644
> --- a/drivers/interconnect/qcom/Kconfig
> +++ b/drivers/interconnect/qcom/Kconfig
> @@ -5,6 +5,11 @@ config INTERCONNECT_QCOM
>  	help
>  	  Support for Qualcomm's Network-on-Chip interconnect hardware.
>  
> +config INTERCONNECT_QCOM_BCM_VOTER
> +	tristate
> +	depends on INTERCONNECT_QCOM || COMPILE_TEST
> +	depends on QCOM_RPMH && OF

This is not user-selectable, but has a "depends on" lines...

> +
>  config INTERCONNECT_QCOM_MSM8916
>  	tristate "Qualcomm MSM8916 interconnect driver"
>  	depends on INTERCONNECT_QCOM
> @@ -32,10 +37,16 @@ config INTERCONNECT_QCOM_QCS404
>  	  This is a driver for the Qualcomm Network-on-Chip on qcs404-based
>  	  platforms.
>  
> +config INTERCONNECT_QCOM_RPMH
> +	tristate
> +	depends on INTERCONNECT_QCOM || COMPILE_TEST
> +	depends on QCOM_COMMAND_DB
> +
>  config INTERCONNECT_QCOM_SDM845
>  	tristate "Qualcomm SDM845 interconnect driver"
>  	depends on INTERCONNECT_QCOM
> -	depends on (QCOM_RPMH && QCOM_COMMAND_DB && OF) || COMPILE_TEST
> +	select INTERCONNECT_QCOM_RPMH
> +	select INTERCONNECT_QCOM_BCM_VOTER

...and these selects will force a symbol to a value without checking its
dependencies. So i was wondering whether this will cause any problems.

>  	help
>  	  This is a driver for the Qualcomm Network-on-Chip on sdm845-based
>  	  platforms.
> diff --git a/drivers/interconnect/qcom/Makefile b/drivers/interconnect/qcom/Makefile
> index e8271575e3d8a..d591bb56273b1 100644
[..]
> +static const struct of_device_id bcm_voter_of_match[] = {
> +	{ .compatible = "qcom,bcm-voter" },
> +	{ }
> +};
> +
> +static struct platform_driver qcom_icc_bcm_voter_driver = {
> +	.probe = qcom_icc_bcm_voter_probe,
> +	.driver = {
> +		.name		= "sdm845_bcm_voter",

Nit: This is not just about sdm845 anymore, so maybe qcom_bcm_voter.

> +		.of_match_table = bcm_voter_of_match,
> +	},
> +};
> +module_platform_driver(qcom_icc_bcm_voter_driver);
> +
> +MODULE_AUTHOR("David Dai <daidavid1@codeaurora.org>");
> +MODULE_DESCRIPTION("Qualcomm BCM Voter interconnect driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/interconnect/qcom/bcm-voter.h b/drivers/interconnect/qcom/bcm-voter.h
> new file mode 100644
> index 0000000000000..3436673e9f104
> --- /dev/null
[.]
> diff --git a/drivers/interconnect/qcom/icc-rpmh.c b/drivers/interconnect/qcom/icc-rpmh.c
> new file mode 100644
> index 0000000000000..e9443b50e0b48
> --- /dev/null
> +++ b/drivers/interconnect/qcom/icc-rpmh.c
> @@ -0,0 +1,147 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2020, The Linux Foundation. All rights reserved.
> + */
> +
> +#include <linux/interconnect.h>
> +#include <linux/interconnect-provider.h>
> +
> +#include "bcm-voter.h"
> +#include "icc-rpmh.h"
> +
> +/**
> + * qcom_icc_pre_aggregate - cleans up stale values from prior icc_set
> + * @node: icc node to operate on
> + */
> +void qcom_icc_pre_aggregate(struct icc_node *node)
> +{
> +	size_t i;
> +	struct qcom_icc_node *qn;
> +
> +	qn = node->data;
> +
> +	for (i = 0; i < QCOM_ICC_NUM_BUCKETS; i++) {
> +		qn->sum_avg[i] = 0;
> +		qn->max_peak[i] = 0;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(qcom_icc_pre_aggregate);
> +
> +/**
> + * qcom_icc_aggregate - aggregate bw for buckets indicated by tag
> + * @node: node to aggregate
> + * @tag: tag to indicate which buckets to aggregate
> + * @avg_bw: new bw to sum aggregate
> + * @peak_bw: new bw to max aggregate
> + * @agg_avg: existing aggregate avg bw val
> + * @agg_peak: existing aggregate peak bw val
> + */
> +int qcom_icc_aggregate(struct icc_node *node, u32 tag, u32 avg_bw,
> +		       u32 peak_bw, u32 *agg_avg, u32 *agg_peak)
> +{
> +	size_t i;
> +	struct qcom_icc_node *qn;
> +	struct qcom_icc_provider *qp;
> +
> +	qn = node->data;
> +	qp = to_qcom_provider(node->provider);
> +
> +	if (!tag)
> +		tag = QCOM_ICC_TAG_ALWAYS;
> +
> +	for (i = 0; i < QCOM_ICC_NUM_BUCKETS; i++) {
> +		if (tag & BIT(i)) {
> +			qn->sum_avg[i] += avg_bw;
> +			qn->max_peak[i] = max_t(u32, qn->max_peak[i], peak_bw);
> +		}
> +	}
> +
> +	*agg_avg += avg_bw;
> +	*agg_peak = max_t(u32, *agg_peak, peak_bw);
> +
> +	for (i = 0; i < qn->num_bcms; i++)
> +		qcom_icc_bcm_voter_add(qp->voter, qn->bcms[i]);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(qcom_icc_aggregate);
> +
> +/**
> + * qcom_icc_set - set the constraints based on path
> + * @src: source node for the path to set constraints on
> + * @dst: destination node for the path to set constraints on
> + *
> + * Return: 0 on success, or an error code otherwise
> + */
> +int qcom_icc_set(struct icc_node *src, struct icc_node *dst)
> +{
> +	struct qcom_icc_provider *qp;
> +	struct icc_node *node;
> +
> +	if (!src)
> +		node = dst;
> +	else
> +		node = src;
> +
> +	qp = to_qcom_provider(node->provider);
> +
> +	qcom_icc_bcm_voter_commit(qp->voter);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(qcom_icc_set);
> +
> +/**
> + * qcom_icc_bcm_init - populates bcm aux data and connect qnodes
> + * @bcm: bcm to be initialized
> + * @dev: associated provider device
> + *
> + * Return: 0 on success, or an error code otherwise
> + */
> +int qcom_icc_bcm_init(struct qcom_icc_bcm *bcm, struct device *dev)
> +{
> +	struct qcom_icc_node *qn;
> +	const struct bcm_db *data;
> +	size_t data_count;
> +	int i;
> +
> +	/* BCM is already initialised*/
> +	if (bcm->addr)
> +		return 0;
> +
> +	bcm->addr = cmd_db_read_addr(bcm->name);
> +	if (!bcm->addr) {
> +		dev_err(dev, "%s could not find RPMh address\n",
> +			bcm->name);
> +		return -EINVAL;
> +	}
> +
> +	data = cmd_db_read_aux_data(bcm->name, &data_count);
> +	if (IS_ERR(data)) {
> +		dev_err(dev, "%s command db read error (%ld)\n",
> +			bcm->name, PTR_ERR(data));
> +		return PTR_ERR(data);
> +	}
> +	if (!data_count) {
> +		dev_err(dev, "%s command db missing or partial aux data\n",
> +			bcm->name);
> +		return -EINVAL;
> +	}
> +
> +	bcm->aux_data.unit = le32_to_cpu(data->unit);
> +	bcm->aux_data.width = le16_to_cpu(data->width);
> +	bcm->aux_data.vcd = data->vcd;
> +	bcm->aux_data.reserved = data->reserved;
> +	INIT_LIST_HEAD(&bcm->list);
> +	INIT_LIST_HEAD(&bcm->ws_list);
> +
> +	/* Link Qnodes to their respective BCMs */
> +	for (i = 0; i < bcm->num_nodes; i++) {
> +		qn = bcm->nodes[i];
> +		qn->bcms[qn->num_bcms] = bcm;
> +		qn->num_bcms++;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(qcom_icc_bcm_init);

When i tried building this as a module i see the following warning:
WARNING: modpost: missing MODULE_LICENSE() in drivers/interconnect/qcom/icc-rpmh.o

So we may want to include module.h and add MODULE_LICENSE("GPL v2") as specified
in the SPDX tag.

Thanks,
Georgi