Re: [PATCH v5 4/8] interconnect: qcom: Add RPM communication

From: Evan Green
Date: Tue Jun 26 2018 - 16:55:08 EST

Hi Georgi,

On Wed, Jun 20, 2018 at 5:11 AM Georgi Djakov <georgi.djakov@xxxxxxxxxx> wrote:
>
> On some Qualcomm SoCs, there is a remote processor, which controls some of
> the Network-On-Chip interconnect resources. Other CPUs express their needs
> by communicating with this processor. Add a driver to handle comminication
> with this remote processor.
>
> Signed-off-by: Georgi Djakov <georgi.djakov@xxxxxxxxxx>
> ---
> .../bindings/interconnect/qcom-smd.txt | 32 +++++++
> drivers/interconnect/qcom/Makefile | 2 +
> drivers/interconnect/qcom/smd-rpm.c | 90 +++++++++++++++++++
> drivers/interconnect/qcom/smd-rpm.h | 15 ++++
> 4 files changed, 139 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/interconnect/qcom-smd.txt
> create mode 100644 drivers/interconnect/qcom/Makefile
> create mode 100644 drivers/interconnect/qcom/smd-rpm.c
> create mode 100644 drivers/interconnect/qcom/smd-rpm.h
>
> diff --git a/Documentation/devicetree/bindings/interconnect/qcom-smd.txt b/Documentation/devicetree/bindings/interconnect/qcom-smd.txt
> new file mode 100644
> index 000000000000..88a5aeb50935
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interconnect/qcom-smd.txt
> @@ -0,0 +1,32 @@
> +Qualcomm SMD-RPM interconnect driver binding
> +------------------------------------------------
> +The RPM (Resource Power Manager) is a dedicated hardware engine
> +for managing the shared SoC resources in order to keep the lowest
> +power profile. It communicates with other hardware subsystems via
> +the shared memory driver (SMD) back-end and accepts requests for
> +various resources.
> +
> +Required properties :
> +- compatible : shall contain only one of the following:
> + "qcom,interconnect-smd-rpm"
> +
> +Example:
> + smd {
> + compatible = "qcom,smd";
> +
> + rpm {
> + interrupts = <0 168 1>;
> + qcom,ipc = <&apcs 8 0>;
> + qcom,smd-edge = <15>;
> +
> + rpm_requests {
> + compatible = "qcom,rpm-msm8916";
> + qcom,smd-channels = "rpm_requests";
> +
> + interconnect-smd-rpm {
> + compatible = "qcom,interconnect-smd-rpm";
> + };
> +
> + };
> + };
> + };
> diff --git a/drivers/interconnect/qcom/Makefile b/drivers/interconnect/qcom/Makefile
> new file mode 100644
> index 000000000000..2a0c41db91c4
> --- /dev/null
> +++ b/drivers/interconnect/qcom/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0
> +obj-y += smd-rpm.o

This new file has an unexpressed dependency on CONFIG_QCOM_SMD_RPM due
to qcom_rpm_smd_write. RPMh-based systems won't need this file, right?
Maybe this file should live behind some config?

> diff --git a/drivers/interconnect/qcom/smd-rpm.c b/drivers/interconnect/qcom/smd-rpm.c
> new file mode 100644
> index 000000000000..0cf772f51642
> --- /dev/null
> +++ b/drivers/interconnect/qcom/smd-rpm.c
> @@ -0,0 +1,90 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * RPM over SMD communication wrapper for interconects
> + *
> + * Copyright (C) 2018 Linaro Ltd
> + * Author: Georgi Djakov <georgi.djakov@xxxxxxxxxx>
> + */
> +
> +#include <linux/interconnect-provider.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/soc/qcom/smd-rpm.h>
> +#include "smd-rpm.h"
> +
> +#define RPM_KEY_BW 0x00007762
> +
> +static struct qcom_icc_rpm {
> + struct qcom_smd_rpm *rpm;
> +} icc_rpm_smd;
> +
> +struct icc_rpm_smd_req {
> + __le32 key;
> + __le32 nbytes;
> + __le32 value;
> +};
> +
> +bool qcom_icc_rpm_smd_available(void)
> +{
> + if (!icc_rpm_smd.rpm)
> + return false;
> +
> + return true;
> +}
> +
> +int qcom_icc_rpm_smd_send(int ctx, int rsc_type, int id, u32 val)
> +{
> + struct icc_rpm_smd_req req = {
> + .key = cpu_to_le32(RPM_KEY_BW),
> + .nbytes = cpu_to_le32(sizeof(u32)),
> + .value = cpu_to_le32(val),
> + };
> +
> + return qcom_rpm_smd_write(icc_rpm_smd.rpm, ctx, rsc_type, id, &req,
> + sizeof(req));
> +}
> +EXPORT_SYMBOL(qcom_icc_rpm_smd_send);
> +
> +static int qcom_icc_rpm_smd_probe(struct platform_device *pdev)
> +{
> + icc_rpm_smd.rpm = dev_get_drvdata(pdev->dev.parent);
> + if (!icc_rpm_smd.rpm) {
> + dev_err(&pdev->dev, "unable to retrieve handle to RPM\n");
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +
> +static const struct of_device_id qcom_icc_rpm_smd_dt_match[] = {
> + { .compatible = "qcom,interconnect-smd-rpm", },
> + { },
> +};
> +
> +MODULE_DEVICE_TABLE(of, qcom_interconnect_rpm_smd_dt_match);
> +
> +static struct platform_driver qcom_interconnect_rpm_smd_driver = {
> + .driver = {
> + .name = "qcom-interconnect-smd-rpm",
> + .of_match_table = qcom_icc_rpm_smd_dt_match,
> + },
> + .probe = qcom_icc_rpm_smd_probe,
> +};
> +
> +static int __init rpm_smd_interconnect_init(void)
> +{
> + return platform_driver_register(&qcom_interconnect_rpm_smd_driver);
> +}
> +subsys_initcall(rpm_smd_interconnect_init);
> +
> +static void __exit rpm_smd_interconnect_exit(void)
> +{
> + platform_driver_unregister(&qcom_interconnect_rpm_smd_driver);
> +}
> +module_exit(rpm_smd_interconnect_exit)
> +
> +MODULE_AUTHOR("Georgi Djakov <georgi.djakov@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Qualcomm SMD RPM interconnect driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/interconnect/qcom/smd-rpm.h b/drivers/interconnect/qcom/smd-rpm.h
> new file mode 100644
> index 000000000000..0f4a3da31cf6
> --- /dev/null
> +++ b/drivers/interconnect/qcom/smd-rpm.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2018, Linaro Ltd.
> + * Author: Georgi Djakov <georgi.djakov@xxxxxxxxxx>
> + */
> +
> +#ifndef __LINUX_INTERCONNECT_QCOM_RPM_H
> +#define __LINUX_INTERCONNECT_QCOM_RPM_H

This doesn't really reflect the path, should this be something different?

> +
> +#include <linux/soc/qcom/smd-rpm.h>
> +
> +bool qcom_icc_rpm_smd_available(void);
> +int qcom_icc_rpm_smd_send(int ctx, int rsc_type, int id, u32 val);
> +
> +#endif