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From:   Evan Green <evgreen@google.com>
Date:   Tue, 4 Feb 2020 10:22:41 -0800
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Subject: Re: [PATCH v2 4/6] interconnect: qcom: Consolidate interconnect RPMh support
To:     David Dai <daidavid1@codeaurora.org>
Cc:     Georgi Djakov <georgi.djakov@linaro.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Rob Herring <robh+dt@kernel.org>, sboyd@kernel.org,
        Lina Iyer <ilina@codeaurora.org>,
        Sean Sweeney <seansw@qti.qualcomm.com>,
        Alex Elder <elder@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        linux-pm@vger.kernel.org
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On Thu, Jan 9, 2020 at 8:33 PM David Dai <daidavid1@codeaurora.org> wrote:
>
> 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>

This was a little tough to wrap my head around, but then I understood
that most of it was a copy of functions from sdm845.c, which are later
deleted in patch 5 when sdm845.c uses the bcm-voter driver.

> ---
>  drivers/interconnect/qcom/Kconfig     |   8 +
>  drivers/interconnect/qcom/Makefile    |   4 +
>  drivers/interconnect/qcom/bcm-voter.c | 363 ++++++++++++++++++++++++++++++++++
>  drivers/interconnect/qcom/bcm-voter.h |  28 +++
>  drivers/interconnect/qcom/icc-rpmh.c  | 158 +++++++++++++++
>  drivers/interconnect/qcom/icc-rpmh.h  | 151 ++++++++++++++
>  6 files changed, 712 insertions(+)
>  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 2f9304d..cd100a4 100644
> --- a/drivers/interconnect/qcom/Kconfig
> +++ b/drivers/interconnect/qcom/Kconfig
> @@ -5,6 +5,9 @@ config INTERCONNECT_QCOM
>         help
>           Support for Qualcomm's Network-on-Chip interconnect hardware.
>
> +config INTERCONNECT_QCOM_BCM_VOTER
> +       tristate
> +
>  config INTERCONNECT_QCOM_MSM8974
>         tristate "Qualcomm MSM8974 interconnect driver"
>         depends on INTERCONNECT_QCOM
> @@ -23,10 +26,15 @@ config INTERCONNECT_QCOM_QCS404
>           This is a driver for the Qualcomm Network-on-Chip on qcs404-based
>           platforms.
>
> +config INTERCONNECT_QCOM_RPMH
> +       tristate
> +
>  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
>         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 9adf9e3..9317fa7 100644
> --- a/drivers/interconnect/qcom/Makefile
> +++ b/drivers/interconnect/qcom/Makefile
> @@ -4,8 +4,12 @@ qnoc-msm8974-objs                      := msm8974.o
>  qnoc-qcs404-objs                       := qcs404.o
>  qnoc-sdm845-objs                       := sdm845.o
>  icc-smd-rpm-objs                       := smd-rpm.o
> +icc-bcm-voter-objs                     := bcm-voter.o
> +icc-rpmh-obj                           := icc-rpmh.o
>
> +obj-$(CONFIG_INTERCONNECT_QCOM_BCM_VOTER) += icc-bcm-voter.o
>  obj-$(CONFIG_INTERCONNECT_QCOM_MSM8974) += qnoc-msm8974.o
>  obj-$(CONFIG_INTERCONNECT_QCOM_QCS404) += qnoc-qcs404.o
> +obj-$(CONFIG_INTERCONNECT_QCOM_RPMH) += icc-rpmh.o
>  obj-$(CONFIG_INTERCONNECT_QCOM_SDM845) += qnoc-sdm845.o
>  obj-$(CONFIG_INTERCONNECT_QCOM_SMD_RPM) += icc-smd-rpm.o
> diff --git a/drivers/interconnect/qcom/bcm-voter.c b/drivers/interconnect/qcom/bcm-voter.c
> new file mode 100644
> index 0000000..a65680e
> --- /dev/null
> +++ b/drivers/interconnect/qcom/bcm-voter.c
> @@ -0,0 +1,363 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019, The Linux Foundation. All rights reserved.
> + *
> + */
> +#include <linux/interconnect-provider.h>
> +#include <linux/list_sort.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +
> +#include <soc/qcom/rpmh.h>
> +#include <soc/qcom/tcs.h>
> +
> +#include "bcm-voter.h"
> +#include "icc-rpmh.h"
> +
> +static LIST_HEAD(bcm_voters);

Doesn't this need a lock?

> +
> +/**
> + * struct bcm_voter - Bus Clock Manager voter
> + * @dev: reference to the device that communicates with the BCM
> + * @np: reference to the device node to match bcm voters
> + * @lock: mutex to protect commit and wake/sleep lists in the voter
> + * @commit_list: list containing bcms to be committed to hardware
> + * @ws_list: list containing bcms that have different wake/sleep votes
> + * @voter_node: list of bcm voters
> + */
> +struct bcm_voter {
> +       struct device *dev;
> +       struct device_node *np;
> +       struct mutex lock;
> +       struct list_head commit_list;
> +       struct list_head ws_list;
> +       struct list_head voter_node;
> +};
> +
> +static int cmp_vcd(void *priv, struct list_head *a, struct list_head *b)
> +{
> +       const struct qcom_icc_bcm *bcm_a =
> +                       list_entry(a, struct qcom_icc_bcm, list);
> +       const struct qcom_icc_bcm *bcm_b =
> +                       list_entry(b, struct qcom_icc_bcm, list);
> +
> +       if (bcm_a->aux_data.vcd < bcm_b->aux_data.vcd)
> +               return -1;
> +       else if (bcm_a->aux_data.vcd == bcm_b->aux_data.vcd)
> +               return 0;
> +       else
> +               return 1;
> +}
> +
> +static void bcm_aggregate(struct qcom_icc_bcm *bcm)
> +{
> +       size_t i, bucket;
> +       u64 agg_avg[QCOM_ICC_NUM_BUCKETS] = {0};
> +       u64 agg_peak[QCOM_ICC_NUM_BUCKETS] = {0};
> +       u64 temp;
> +
> +       for (bucket = 0; bucket < QCOM_ICC_NUM_BUCKETS; bucket++) {
> +               for (i = 0; i < bcm->num_nodes; i++) {
> +                       temp = bcm->nodes[i]->sum_avg[bucket] * bcm->aux_data.width;
> +                       do_div(temp, bcm->nodes[i]->buswidth * bcm->nodes[i]->channels);
> +                       agg_avg[bucket] = max(agg_avg[bucket], temp);
> +
> +                       temp = bcm->nodes[i]->max_peak[bucket] * bcm->aux_data.width;
> +                       do_div(temp, bcm->nodes[i]->buswidth);
> +                       agg_peak[bucket] = max(agg_peak[bucket], temp);
> +               }
> +
> +               temp = agg_avg[bucket] * 1000ULL;
> +               do_div(temp, bcm->aux_data.unit);
> +               bcm->vote_x[bucket] = temp;
> +
> +               temp = agg_peak[bucket] * 1000ULL;
> +               do_div(temp, bcm->aux_data.unit);
> +               bcm->vote_y[bucket] = temp;
> +       }
> +
> +       if (bcm->keepalive && bcm->vote_x[QCOM_ICC_BUCKET_AMC] == 0 &&
> +           bcm->vote_y[QCOM_ICC_BUCKET_AMC] == 0) {
> +               bcm->vote_x[QCOM_ICC_BUCKET_AMC] = 1;
> +               bcm->vote_x[QCOM_ICC_BUCKET_WAKE] = 1;
> +               bcm->vote_y[QCOM_ICC_BUCKET_AMC] = 1;
> +               bcm->vote_y[QCOM_ICC_BUCKET_WAKE] = 1;
> +       }
> +}
> +
> +static inline void tcs_cmd_gen(struct tcs_cmd *cmd, u64 vote_x, u64 vote_y,
> +                       u32 addr, bool commit)
> +{
> +       bool valid = true;
> +
> +       if (!cmd)
> +               return;
> +
> +       if (vote_x == 0 && vote_y == 0)
> +               valid = false;
> +
> +       if (vote_x > BCM_TCS_CMD_VOTE_MASK)
> +               vote_x = BCM_TCS_CMD_VOTE_MASK;
> +
> +       if (vote_y > BCM_TCS_CMD_VOTE_MASK)
> +               vote_y = BCM_TCS_CMD_VOTE_MASK;
> +
> +       cmd->addr = addr;
> +       cmd->data = BCM_TCS_CMD(commit, valid, vote_x, vote_y);
> +
> +       /*
> +        * Set the wait for completion flag on command that need to be completed
> +        * before the next command.
> +        */
> +       if (commit)
> +               cmd->wait = true;
> +}
> +
> +static void tcs_list_gen(struct list_head *bcm_list, int bucket,
> +                        struct tcs_cmd tcs_list[MAX_VCD],
> +                        int n[MAX_VCD])

"n" should really be MAX_VCD + 1 to guarantee that it's
zero-terminated, otherwise rpmh_write_batch() could go nuts.

> +{
> +       struct qcom_icc_bcm *bcm;
> +       bool commit;
> +       size_t idx = 0, batch = 0, cur_vcd_size = 0;
> +
> +       memset(n, 0, sizeof(int) * MAX_VCD);
> +
> +       list_for_each_entry(bcm, bcm_list, list) {
> +               commit = false;
> +               cur_vcd_size++;
> +               if ((list_is_last(&bcm->list, bcm_list)) ||
> +                   bcm->aux_data.vcd != list_next_entry(bcm, list)->aux_data.vcd) {
> +                       commit = true;
> +                       cur_vcd_size = 0;
> +               }
> +               tcs_cmd_gen(&tcs_list[idx], bcm->vote_x[bucket],
> +                           bcm->vote_y[bucket], bcm->addr, commit);
> +               idx++;
> +               n[batch]++;
> +               /*
> +                * Batch the BCMs in such a way that we do not split them in
> +                * multiple payloads when they are under the same VCD. This is
> +                * to ensure that every BCM is committed since we only set the
> +                * commit bit on the last BCM request of every VCD.
> +                */
> +               if (n[batch] >= MAX_RPMH_PAYLOAD) {
> +                       if (!commit) {
> +                               n[batch] = cur_vcd_size;

You lost what used to be a -= here to just an = during the copy from
sdm845.c. How did that happen?

> +                               n[batch + 1] = cur_vcd_size;
> +                       }
> +                       batch++;
> +               }
> +       }
> +}
> +
> +/**
> + * of_bcm_voter_get - gets a bcm voter handle from DT node
> + * @dev: device pointer for the consumer device
> + * @name: name for the bcm voter device
> + *
> + * This function will match a device_node pointer for the phandle
> + * specified in the device DT and return a bcm_voter handle on success.
> + *
> + * Returns bcm_voter pointer or ERR_PTR() on error. EPROBE_DEFER is returned
> + * when matching bcm voter is yet to be found.
> + */
> +struct bcm_voter *of_bcm_voter_get(struct device *dev, const char *name)
> +{
> +       struct bcm_voter *voter = ERR_PTR(-EPROBE_DEFER);
> +       struct bcm_voter *temp;
> +       struct device_node *np, *node;
> +       int idx = 0;
> +
> +       if (!dev || !dev->of_node)
> +               return ERR_PTR(-ENODEV);
> +
> +       np = dev->of_node;
> +
> +       if (name) {
> +               idx = of_property_match_string(np, "qcom,bcm-voter-names", name);
> +               if (idx < 0)
> +                       return ERR_PTR(idx);
> +       }
> +
> +       node = of_parse_phandle(np, "qcom,bcm-voters", idx);
> +
> +       list_for_each_entry(temp, &bcm_voters, voter_node) {
> +               if (temp->np == node) {
> +                       voter = temp;
> +                       break;
> +               }
> +       }
> +
> +       return voter;
> +}
> +EXPORT_SYMBOL_GPL(of_bcm_voter_get);
> +
> +/**
> + * qcom_icc_bcm_voter_add - queues up the bcm nodes that require updates
> + * @voter: voter that the bcms are being added to
> + * @bcm: bcm to add to the commit and wake sleep list
> + */
> +void qcom_icc_bcm_voter_add(struct bcm_voter *voter, struct qcom_icc_bcm *bcm)
> +{
> +       if (!voter)
> +               return;
> +
> +       mutex_lock(&voter->lock);
> +       if (list_empty(&bcm->list))
> +               list_add_tail(&bcm->list, &voter->commit_list);
> +
> +       if (list_empty(&bcm->ws_list))
> +               list_add_tail(&bcm->ws_list, &voter->ws_list);
> +
> +       mutex_unlock(&voter->lock);
> +}
> +EXPORT_SYMBOL_GPL(qcom_icc_bcm_voter_add);
> +
> +/**
> + * qcom_icc_bcm_voter_commit - generates and commits tcs cmds based on bcms
> + * @voter: voter that needs flushing
> + *
> + * This function generates a set of AMC commands and flushes to the BCM device
> + * associated with the voter. It conditionally generate WAKE and SLEEP commands
> + * based on deltas between WAKE/SLEEP requirements. The ws_list persists
> + * through multiple commit requests and bcm nodes are removed only when the
> + * requirements for WAKE matches SLEEP.
> + *
> + * Returns 0 on success, or an appropriate error code otherwise.
> + */
> +int qcom_icc_bcm_voter_commit(struct bcm_voter *voter)
> +{
> +       struct qcom_icc_bcm *bcm;
> +       struct qcom_icc_bcm *bcm_tmp;
> +       int commit_idx[MAX_VCD];
> +       struct tcs_cmd cmds[MAX_BCMS];
> +       int ret = 0;
> +
> +       if (!voter)
> +               return 0;
> +
> +       mutex_lock(&voter->lock);
> +       list_for_each_entry(bcm, &voter->commit_list, list)
> +               bcm_aggregate(bcm);
> +
> +       /*
> +        * Pre sort the BCMs based on VCD for ease of generating a command list
> +        * that groups the BCMs with the same VCD together. VCDs are numbered
> +        * with lowest being the most expensive time wise, ensuring that
> +        * those commands are being sent the earliest in the queue. This needs
> +        * to be sorted every commit since we can't guarantee the order in which
> +        * the BCMs are added to the list.
> +        */
> +       list_sort(NULL, &voter->commit_list, cmp_vcd);
> +
> +       /*
> +        * Construct the command list based on a pre ordered list of BCMs
> +        * based on VCD.
> +        */
> +       tcs_list_gen(&voter->commit_list, QCOM_ICC_BUCKET_AMC, cmds, commit_idx);
> +
> +       if (!commit_idx[0])
> +               goto out;
> +
> +       ret = rpmh_invalidate(voter->dev);
> +       if (ret) {
> +               pr_err("Error invalidating RPMH client (%d)\n", ret);
> +               goto out;
> +       }
> +
> +       ret = rpmh_write_batch(voter->dev, RPMH_ACTIVE_ONLY_STATE,
> +                              cmds, commit_idx);
> +       if (ret) {
> +               pr_err("Error sending AMC RPMH requests (%d)\n", ret);
> +               goto out;
> +       }
> +
> +       list_for_each_entry_safe(bcm, bcm_tmp, &voter->commit_list, list)
> +               list_del_init(&bcm->list);
> +
> +       INIT_LIST_HEAD(&voter->commit_list);

This isn't necessary, you just carefully cherry-picked everything off
the list in the previous line.

> +
> +       list_for_each_entry_safe(bcm, bcm_tmp, &voter->ws_list, ws_list) {
> +               /*
> +                * Only generate WAKE and SLEEP commands if a resource's
> +                * requirements change as the execution environment transitions
> +                * between different power states.
> +                */
> +               if (bcm->vote_x[QCOM_ICC_BUCKET_WAKE] !=
> +                   bcm->vote_x[QCOM_ICC_BUCKET_SLEEP] ||
> +                   bcm->vote_y[QCOM_ICC_BUCKET_WAKE] !=
> +                   bcm->vote_y[QCOM_ICC_BUCKET_SLEEP])
> +                       list_add_tail(&bcm->list, &voter->commit_list);
> +               else
> +                       list_del_init(&bcm->ws_list);
> +       }
> +
> +       if (list_empty(&voter->commit_list))
> +               goto out;
> +
> +       list_sort(NULL, &voter->commit_list, cmp_vcd);
> +
> +       tcs_list_gen(&voter->commit_list, QCOM_ICC_BUCKET_WAKE, cmds, commit_idx);
> +
> +       ret = rpmh_write_batch(voter->dev, RPMH_WAKE_ONLY_STATE, cmds, commit_idx);
> +       if (ret) {
> +               pr_err("Error sending WAKE RPMH requests (%d)\n", ret);
> +               goto out;
> +       }
> +
> +       tcs_list_gen(&voter->commit_list, QCOM_ICC_BUCKET_SLEEP, cmds, commit_idx);
> +
> +       ret = rpmh_write_batch(voter->dev, RPMH_SLEEP_STATE, cmds, commit_idx);
> +       if (ret) {
> +               pr_err("Error sending SLEEP RPMH requests (%d)\n", ret);
> +               goto out;
> +       }
> +
> +out:
> +       list_for_each_entry_safe(bcm, bcm_tmp, &voter->commit_list, list)
> +               list_del_init(&bcm->list);
> +
> +       INIT_LIST_HEAD(&voter->commit_list);

You can also remove this.


> +       mutex_unlock(&voter->lock);
> +       return ret;
> +}
> +EXPORT_SYMBOL_GPL(qcom_icc_bcm_voter_commit);
> +
> +static int qcom_icc_bcm_voter_probe(struct platform_device *pdev)
> +{
> +       struct bcm_voter *voter;
> +
> +       voter = devm_kzalloc(&pdev->dev, sizeof(*voter), GFP_KERNEL);
> +       if (!voter)
> +               return -ENOMEM;
> +
> +       voter->dev = &pdev->dev;
> +       voter->np = pdev->dev.of_node;
> +       mutex_init(&voter->lock);
> +       INIT_LIST_HEAD(&voter->commit_list);
> +       INIT_LIST_HEAD(&voter->ws_list);
> +       list_add_tail(&voter->voter_node, &bcm_voters);
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id bcm_voter_of_match[] = {
> +       { .compatible = "qcom,sdm845-bcm-voter" },
> +       { },
> +};
> +
> +static struct platform_driver qcom_icc_bcm_voter_driver = {
> +       .probe = qcom_icc_bcm_voter_probe,
> +       .driver = {
> +               .name           = "sdm845_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 0000000..808b068
> --- /dev/null
> +++ b/drivers/interconnect/qcom/bcm-voter.h
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2019, The Linux Foundation. All rights reserved.
> + *
> + */
> +
> +#ifndef __DRIVERS_INTERCONNECT_QCOM_BCM_VOTER_H__
> +#define __DRIVERS_INTERCONNECT_QCOM_BCM_VOTER_H__
> +
> +#include <soc/qcom/cmd-db.h>
> +#include <soc/qcom/rpmh.h>
> +#include <soc/qcom/tcs.h>
> +
> +#include "icc-rpmh.h"
> +
> +#define DEFINE_QBCM(_name, _bcmname, _keepalive, _numnodes, ...)       \
> +               static struct qcom_icc_bcm _name = {                    \
> +               .name = _bcmname,                                       \
> +               .keepalive = _keepalive,                                \
> +               .num_nodes = _numnodes,                                 \
> +               .nodes = { __VA_ARGS__ },                               \
> +       }
> +
> +struct bcm_voter *of_bcm_voter_get(struct device *dev, const char *name);
> +void qcom_icc_bcm_voter_add(struct bcm_voter *voter, struct qcom_icc_bcm *bcm);
> +int qcom_icc_bcm_voter_commit(struct bcm_voter *voter);
> +
> +#endif
> diff --git a/drivers/interconnect/qcom/icc-rpmh.c b/drivers/interconnect/qcom/icc-rpmh.c
> new file mode 100644
> index 0000000..09ad9fe
> --- /dev/null
> +++ b/drivers/interconnect/qcom/icc-rpmh.c
> @@ -0,0 +1,158 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019, The Linux Foundation. All rights reserved.
> + *
> + */
> +
> +#include <asm/div64.h>
> +#include <dt-bindings/interconnect/qcom,sdm845.h>
> +#include <linux/interconnect.h>
> +#include <linux/interconnect-provider.h>
> +#include <linux/module.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;
> +       int ret = 0;
> +
> +       if (!src)
> +               node = dst;
> +       else
> +               node = src;
> +
> +       qp = to_qcom_provider(node->provider);
> +
> +       qcom_icc_bcm_voter_commit(qp->voter);
> +
> +       return ret;
> +}
> +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->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);
> +
> +static struct platform_driver qcom_icc_rpmh_driver = {
> +       .driver = {
> +               .name           = "icc_rpmh",
> +       },
> +};
> +module_platform_driver(qcom_icc_rpmh_driver);
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/interconnect/qcom/icc-rpmh.h b/drivers/interconnect/qcom/icc-rpmh.h
> new file mode 100644
> index 0000000..0ff8f8d
> --- /dev/null
> +++ b/drivers/interconnect/qcom/icc-rpmh.h
> @@ -0,0 +1,151 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2019, The Linux Foundation. All rights reserved.
> + *
> + */
> +
> +#ifndef __DRIVERS_INTERCONNECT_QCOM_ICC_RPMH_H__
> +#define __DRIVERS_INTERCONNECT_QCOM_ICC_RPMH_H__
> +
> +#define to_qcom_provider(_provider) \
> +       container_of(_provider, struct qcom_icc_provider, provider)
> +
> +/**
> + * struct qcom_icc_provider - Qualcomm specific interconnect provider
> + * @provider: generic interconnect provider
> + * @dev: reference to the NoC device
> + * @bcms: list of bcms that maps to the provider
> + * @num_bcms: number of @bcms
> + * @voter: bcm voter targeted by this provider
> + */
> +struct qcom_icc_provider {
> +       struct icc_provider provider;
> +       struct device *dev;
> +       struct qcom_icc_bcm **bcms;
> +       size_t num_bcms;
> +       struct bcm_voter *voter;
> +};
> +
> +/**
> + * struct bcm_db - Auxiliary data pertaining to each Bus Clock Manager (BCM)
> + * @unit: divisor used to convert bytes/sec bw value to an RPMh msg
> + * @width: multiplier used to convert bytes/sec bw value to an RPMh msg
> + * @vcd: virtual clock domain that this bcm belongs to
> + * @reserved: reserved field
> + */
> +struct bcm_db {
> +       __le32 unit;
> +       __le16 width;
> +       u8 vcd;
> +       u8 reserved;
> +};
> +
> +#define MAX_LINKS              128
> +#define MAX_BCMS               64
> +#define MAX_BCM_PER_NODE       3
> +#define MAX_VCD                        10
> +
> +/*
> + * The AMC bucket denotes constraints that are applied to hardware when
> + * icc_set_bw() completes, whereas the WAKE and SLEEP constraints are applied
> + * when the execution environment transitions between active and low power mode.
> + */
> +#define QCOM_ICC_BUCKET_AMC            0
> +#define QCOM_ICC_BUCKET_WAKE           1
> +#define QCOM_ICC_BUCKET_SLEEP          2
> +#define QCOM_ICC_NUM_BUCKETS           3
> +#define QCOM_ICC_TAG_AMC               BIT(QCOM_ICC_BUCKET_AMC)
> +#define QCOM_ICC_TAG_WAKE              BIT(QCOM_ICC_BUCKET_WAKE)
> +#define QCOM_ICC_TAG_SLEEP             BIT(QCOM_ICC_BUCKET_SLEEP)
> +#define QCOM_ICC_TAG_ACTIVE_ONLY       (QCOM_ICC_TAG_AMC | QCOM_ICC_TAG_WAKE)
> +#define QCOM_ICC_TAG_ALWAYS            (QCOM_ICC_TAG_AMC | QCOM_ICC_TAG_WAKE |\
> +                                        QCOM_ICC_TAG_SLEEP)
> +
> +/**
> + * struct qcom_icc_node - Qualcomm specific interconnect nodes
> + * @name: the node name used in debugfs
> + * @links: an array of nodes where we can go next while traversing
> + * @id: a unique node identifier
> + * @num_links: the total number of @links
> + * @channels: num of channels at this node
> + * @buswidth: width of the interconnect between a node and the bus
> + * @sum_avg: current sum aggregate value of all avg bw requests
> + * @max_peak: current max aggregate value of all peak bw requests
> + * @bcms: list of bcms associated with this logical node
> + * @num_bcms: num of @bcms
> + */
> +struct qcom_icc_node {
> +       const char *name;
> +       u16 links[MAX_LINKS];
> +       u16 id;
> +       u16 num_links;
> +       u16 channels;
> +       u16 buswidth;
> +       u64 sum_avg[QCOM_ICC_NUM_BUCKETS];
> +       u64 max_peak[QCOM_ICC_NUM_BUCKETS];
> +       struct qcom_icc_bcm *bcms[MAX_BCM_PER_NODE];
> +       size_t num_bcms;
> +};
> +
> +/**
> + * struct qcom_icc_bcm - Qualcomm specific hardware accelerator nodes
> + * known as Bus Clock Manager (BCM)
> + * @name: the bcm node name used to fetch BCM data from command db
> + * @type: latency or bandwidth bcm
> + * @addr: address offsets used when voting to RPMH
> + * @vote_x: aggregated threshold values, represents sum_bw when @type is bw bcm
> + * @vote_y: aggregated threshold values, represents peak_bw when @type is bw bcm
> + * @dirty: flag used to indicate whether the bcm needs to be committed
> + * @keepalive: flag used to indicate whether a keepalive is required
> + * @aux_data: auxiliary data used when calculating threshold values and
> + * communicating with RPMh
> + * @list: used to link to other bcms when compiling lists for commit
> + * @ws_list: used to keep track of bcms that may transition between wake/sleep
> + * @num_nodes: total number of @num_nodes
> + * @nodes: list of qcom_icc_nodes that this BCM encapsulates
> + */
> +struct qcom_icc_bcm {
> +       const char *name;
> +       u32 type;
> +       u32 addr;
> +       u64 vote_x[QCOM_ICC_NUM_BUCKETS];
> +       u64 vote_y[QCOM_ICC_NUM_BUCKETS];
> +       bool dirty;
> +       bool keepalive;
> +       struct bcm_db aux_data;
> +       struct list_head list;
> +       struct list_head ws_list;
> +       size_t num_nodes;
> +       struct qcom_icc_node *nodes[];
> +};
> +
> +struct qcom_icc_fabric {
> +       struct qcom_icc_node **nodes;
> +       size_t num_nodes;
> +};
> +
> +struct qcom_icc_desc {
> +       struct qcom_icc_node **nodes;
> +       size_t num_nodes;
> +       struct qcom_icc_bcm **bcms;
> +       size_t num_bcms;
> +};
> +
> +#define DEFINE_QNODE(_name, _id, _channels, _buswidth,                 \
> +                       _numlinks, ...)                                 \
> +               static struct qcom_icc_node _name = {                   \
> +               .id = _id,                                              \
> +               .name = #_name,                                         \
> +               .channels = _channels,                                  \
> +               .buswidth = _buswidth,                                  \
> +               .num_links = _numlinks,                                 \
> +               .links = { __VA_ARGS__ },                               \
> +       }
> +
> +int qcom_icc_aggregate(struct icc_node *node, u32 tag, u32 avg_bw,
> +                      u32 peak_bw, u32 *agg_avg, u32 *agg_peak);
> +int qcom_icc_set(struct icc_node *src, struct icc_node *dst);
> +int qcom_icc_bcm_init(struct qcom_icc_bcm *bcm, struct device *dev);
> +void qcom_icc_pre_aggregate(struct icc_node *node);
> +
> +#endif
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project