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Message-ID: <8b1614c5-7634-6681-b19a-cb2c68e80c61@linaro.org>
Date: Thu, 17 Nov 2022 14:05:39 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>, agross@...nel.org
Cc: andersson@...nel.org, konrad.dybcio@...ainline.org,
robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, marijn.suijten@...ainline.org,
kernel@...labora.com
Subject: Re: [PATCH v3 2/2] soc: qcom: Add Qualcomm Ramp Controller driver
On 15/11/2022 18:45, AngeloGioacchino Del Regno wrote:
> The Ramp Controller is used to program the sequence ID for pulse
> swallowing, enable sequence and linking sequence IDs for the CPU
> cores on some Qualcomm SoCs.
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> ---
> drivers/soc/qcom/Kconfig | 9 +
> drivers/soc/qcom/Makefile | 1 +
> drivers/soc/qcom/ramp_controller.c | 331 +++++++++++++++++++++++++++++
> 3 files changed, 341 insertions(+)
> create mode 100644 drivers/soc/qcom/ramp_controller.c
>
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index 024e420f1bb7..d174183a26f7 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -95,6 +95,15 @@ config QCOM_QMI_HELPERS
> tristate
> depends on NET
>
> +config QCOM_RAMP_CTRL
> + tristate "Qualcomm Ramp Controller driver"
> + depends on ARCH_QCOM || COMPILE_TEST
> + help
> + The Ramp Controller is used to program the sequence ID for pulse
> + swallowing, enable sequence and link sequence IDs for the CPU
> + cores on some Qualcomm SoCs.
> + Say y here to enable support for the ramp controller.
> +
> config QCOM_RMTFS_MEM
> tristate "Qualcomm Remote Filesystem memory driver"
> depends on ARCH_QCOM
> diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
> index d66604aff2b0..6e02333c4080 100644
> --- a/drivers/soc/qcom/Makefile
> +++ b/drivers/soc/qcom/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_QCOM_OCMEM) += ocmem.o
> obj-$(CONFIG_QCOM_PDR_HELPERS) += pdr_interface.o
> obj-$(CONFIG_QCOM_QMI_HELPERS) += qmi_helpers.o
> qmi_helpers-y += qmi_encdec.o qmi_interface.o
> +obj-$(CONFIG_QCOM_RAMP_CTRL) += ramp_controller.o
> obj-$(CONFIG_QCOM_RMTFS_MEM) += rmtfs_mem.o
> obj-$(CONFIG_QCOM_RPMH) += qcom_rpmh.o
> qcom_rpmh-y += rpmh-rsc.o
> diff --git a/drivers/soc/qcom/ramp_controller.c b/drivers/soc/qcom/ramp_controller.c
> new file mode 100644
> index 000000000000..b403493f3541
> --- /dev/null
> +++ b/drivers/soc/qcom/ramp_controller.c
> @@ -0,0 +1,331 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Qualcomm Ramp Controller driver
> + * Copyright (c) 2022, AngeloGioacchino Del Regno
> + * <angelogioacchino.delregno@...labora.com>
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/types.h>
> +
> +#define RC_UPDATE_EN BIT(0)
> +#define RC_ROOT_EN BIT(1)
> +
> +#define RC_REG_CFG_UPDATE 0x60
> +#define RC_CFG_UPDATE_EN BIT(8)
> +#define RC_CFG_ACK GENMASK(31, 16)
> +
> +#define RC_DCVS_CFG_SID 2
> +#define RC_LINK_SID 3
> +#define RC_LMH_SID 6
> +#define RC_DFS_SID 14
> +
> +#define RC_UPDATE_TIMEOUT_US 500
> +
> +/**
> + * struct qcom_ramp_controller_desc - SoC specific parameters
> + * @cfg_dfs_sid: Dynamic Frequency Scaling SID configuration
> + * @cfg_link_sid: Link SID configuration
> + * @cfg_lmh_sid: Limits Management hardware SID configuration
> + * @cfg_ramp_pre_en: Ramp Controller pre-enable sequence
> + * @cfg_ramp_en: Ramp Controller enable sequence
> + * @cfg_ramp_post_en: Ramp Controller post-enable sequence
> + * @cfg_ramp_dis: Ramp Controller disable sequence
> + * @cmd_reg: Command register offset
> + * @num_dfs_sids: Number of DFS SIDs (max 8)
> + * @num_link_sids: Number of Link SIDs (max 3)
> + * @num_lmh_sids: Number of LMh SIDs (max 8)
> + */
> +struct qcom_ramp_controller_desc {
> + const struct reg_sequence *cfg_dfs_sid;
> + const struct reg_sequence *cfg_link_sid;
> + const struct reg_sequence *cfg_lmh_sid;
> + const struct reg_sequence *cfg_ramp_pre_en;
> + const struct reg_sequence *cfg_ramp_en;
> + const struct reg_sequence *cfg_ramp_post_en;
> + const struct reg_sequence *cfg_ramp_dis;
> + u8 cmd_reg;
> + u8 num_dfs_sids;
> + u8 num_link_sids;
> + u8 num_lmh_sids;
> +};
> +
> +/**
> + * struct qcom_ramp_controller - Main driver structure
> + * @regmap: Regmap handle
> + * @desc: SoC specific parameters
> + */
> +struct qcom_ramp_controller {
> + struct regmap *regmap;
> + const struct qcom_ramp_controller_desc *desc;
> +};
> +
> +/**
> + * rc_wait_for_update() - Wait for Ramp Controller root update
> + * @qrc: Main driver structure
> + *
> + * Return: Zero for success or negative number for failure
> + */
> +static int rc_wait_for_update(struct qcom_ramp_controller *qrc)
> +{
> + const struct qcom_ramp_controller_desc *d = qrc->desc;
> + struct regmap *r = qrc->regmap;
> + u32 val;
> + int ret;
> +
> + ret = regmap_set_bits(r, d->cmd_reg, RC_ROOT_EN);
> + if (ret)
> + return ret;
> +
> + return regmap_read_poll_timeout(r, d->cmd_reg, val, !(val & RC_UPDATE_EN),
> + 1, RC_UPDATE_TIMEOUT_US);
> +}
> +
> +/**
> + * rc_set_cfg_update() - Ramp Controller configuration update
> + * @qrc: Main driver structure
> + * @ce: Configuration entry to update
> + *
> + * Return: Zero for success or negative number for failure
> + */
> +static int rc_set_cfg_update(struct qcom_ramp_controller *qrc, u8 ce)
> +{
> + const struct qcom_ramp_controller_desc *d = qrc->desc;
> + struct regmap *r = qrc->regmap;
> + u32 ack, val;
> + int ret;
> +
> + /* The ack bit is between bits 16-31 of RC_REG_CFG_UPDATE */
> + ack = FIELD_PREP(RC_CFG_ACK, BIT(ce));
> +
> + /* Write the configuration type first... */
> + ret = regmap_set_bits(r, d->cmd_reg + RC_REG_CFG_UPDATE, ce);
> + if (ret)
> + return ret;
> +
> + /* ...and after that, enable the update bit to sync the changes */
> + ret = regmap_set_bits(r, d->cmd_reg + RC_REG_CFG_UPDATE, RC_CFG_UPDATE_EN);
> + if (ret)
> + return ret;
> +
> + /* Wait for the changes to go through */
> + ret = regmap_read_poll_timeout(r, d->cmd_reg + RC_REG_CFG_UPDATE, val,
> + val & ack, 1, RC_UPDATE_TIMEOUT_US);
> + if (ret)
> + return ret;
> +
> + /*
> + * Configuration update success! The CFG_UPDATE register will not be
> + * cleared automatically upon applying the configuration, so we have
> + * to do that manually in order to leave the ramp controller in a
> + * predictable and clean state.
> + */
> + ret = regmap_write(r, d->cmd_reg + RC_REG_CFG_UPDATE, 0);
> + if (ret)
> + return ret;
> +
> + /* Wait for the update bit cleared ack */
> + return regmap_read_poll_timeout(r, d->cmd_reg + RC_REG_CFG_UPDATE,
> + val, !(val & RC_CFG_ACK), 1,
> + RC_UPDATE_TIMEOUT_US);
> +}
> +
> +/**
> + * rc_write_cfg - Send configuration sequence
> + * @qrc: Main driver structure
> + * @seq: Register sequence to send before asking for update
> + * @ce: Configuration SID
> + * @nsids: Total number of SIDs
> + *
> + * Returns: Zero for success or negative number for error
> + */
> +static int rc_write_cfg(struct qcom_ramp_controller *qrc,
> + const struct reg_sequence *seq,
> + u16 ce, u8 nsids)
> +{
> + int ret;
> + u8 i;
> +
> + /* Check if, and wait until the ramp controller is ready */
> + ret = rc_wait_for_update(qrc);
> + if (ret)
> + return ret;
> +
> + /* Write the sequence */
> + ret = regmap_multi_reg_write(qrc->regmap, seq, nsids);
> + if (ret)
> + return ret;
> +
> + /* Pull the trigger: do config update starting from the last sid */
> + for (i = 0; i < nsids; i++) {
> + ret = rc_set_cfg_update(qrc, (u8)ce - i);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * rc_ramp_ctrl_enable() - Enable Ramp up/down Control
> + * @qrc: Main driver structure
> + *
> + * Return: Zero for success or negative number for error
> + */
> +static int rc_ramp_ctrl_enable(struct qcom_ramp_controller *qrc)
> +{
> + const struct qcom_ramp_controller_desc *d = qrc->desc;
> + int ret;
> +
> + ret = rc_write_cfg(qrc, d->cfg_ramp_pre_en, RC_DCVS_CFG_SID, 1);
ARRAY_SIZE or num_somthing (here and below)
> + if (ret)
> + return ret;
> +
> + ret = rc_write_cfg(qrc, d->cfg_ramp_en, RC_DCVS_CFG_SID, 1);
> + if (ret)
> + return ret;
> +
> + return rc_write_cfg(qrc, d->cfg_ramp_post_en, RC_DCVS_CFG_SID, 1);
Is there any benefit from having separate pre_en, en and post_en configs
here? I'd suggest using a single array in the configuration.
> +}
> +
> +/**
> + * qcom_ramp_controller_start() - Initialize and start the ramp controller
> + * @qrc: Main driver structure
> + *
> + * The Ramp Controller needs to be initialized by programming the relevant
> + * registers with SoC-specific configuration: once programming is done,
> + * the hardware will take care of the rest (no further handling required).
> + *
> + * Return: Zero for success or negative number for error
> + */
> +static int qcom_ramp_controller_start(struct qcom_ramp_controller *qrc)
> +{
> + const struct qcom_ramp_controller_desc *d = qrc->desc;
> + int ret;
> +
> + /* Program LMH, DFS, Link SIDs */
> + ret = rc_write_cfg(qrc, d->cfg_lmh_sid, RC_LMH_SID, d->num_lmh_sids);
> + if (ret)
> + return ret;
> +
> + ret = rc_write_cfg(qrc, d->cfg_dfs_sid, RC_DFS_SID, d->num_dfs_sids);
> + if (ret)
> + return ret;
> +
> + ret = rc_write_cfg(qrc, d->cfg_link_sid, RC_LINK_SID, d->num_link_sids);
> + if (ret)
> + return ret;
> +
> + /* Everything is ready! Enable the ramp up/down control */
> + return rc_ramp_ctrl_enable(qrc);
> +}
> +
> +static const struct regmap_config qrc_regmap_config = {
> + .reg_bits = 32,
> + .reg_stride = 4,
> + .val_bits = 32,
> + .max_register = 0x68,
> + .fast_io = true,
> +};
> +
> +static const struct qcom_ramp_controller_desc msm8976_rc_cfg = {
> + .cfg_dfs_sid = (const struct reg_sequence[]) {
> + { 0x10, 0xfefebff7 },
> + { 0x14, 0xfdff7fef },
> + { 0x18, 0xfbffdefb },
> + { 0x1c, 0xb69b5555 },
> + { 0x20, 0x24929249 },
> + { 0x24, 0x49241112 },
> + { 0x28, 0x11112111 },
> + { 0x2c, 0x8102 },
> + },
Please move these config arrays to the named constants. This would allow
you to use ARRAY_SIZE below, for num_foo_sids variables.
> + .cfg_link_sid = (const struct reg_sequence[]) {
> + { 0x40, 0xfc987 },
> + },
> + .cfg_lmh_sid = (const struct reg_sequence[]) {
> + { 0x30, 0x77706db },
> + { 0x34, 0x5550249 },
> + { 0x38, 0x111 },
> + },
> + .cfg_ramp_pre_en = (const struct reg_sequence[]) {
> + { 0x50, 0x800 },
> + },
> + .cfg_ramp_en = (const struct reg_sequence[]) {
> + { 0x50, 0xc00 },
> + },
> + .cfg_ramp_post_en = (const struct reg_sequence[]) {
> + { 0x50, 0x400 },
> + },
> + .cfg_ramp_dis = (const struct reg_sequence[]) {
> + { 0x50, 0x0 },
> + },
> + .cmd_reg = 0x0,
> +
> + .num_dfs_sids = 8,
> + .num_lmh_sids = 3,
> + .num_link_sids = 1,
> +};
> +
> +static int qcom_ramp_controller_probe(struct platform_device *pdev)
> +{
> + struct qcom_ramp_controller *qrc;
> + void __iomem *base;
> +
> + base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(base))
> + return PTR_ERR(base);
> +
> + qrc = devm_kmalloc(&pdev->dev, sizeof(*qrc), GFP_KERNEL);
> + if (!qrc)
> + return -ENOMEM;
> +
> + qrc->desc = device_get_match_data(&pdev->dev);
> + if (!qrc)
> + return -EINVAL;
> +
> + qrc->regmap = devm_regmap_init_mmio(&pdev->dev, base, &qrc_regmap_config);
> + if (IS_ERR(qrc->regmap))
> + return PTR_ERR(qrc->regmap);
> +
> + platform_set_drvdata(pdev, qrc);
> +
> + return qcom_ramp_controller_start(qrc);
> +}
> +
> +static int qcom_ramp_controller_remove(struct platform_device *pdev)
> +{
> + struct qcom_ramp_controller *qrc = platform_get_drvdata(pdev);
> +
> + return rc_write_cfg(qrc, qrc->desc->cfg_ramp_dis, RC_DCVS_CFG_SID, 1);
ARRAY_SIZE or num_something
> +}
> +
> +static const struct of_device_id qcom_ramp_controller_match_table[] = {
> + { .compatible = "qcom,msm8976-ramp-controller", .data = &msm8976_rc_cfg },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, qcom_ramp_controller_match_table);
> +
> +static struct platform_driver qcom_ramp_controller_driver = {
> + .driver = {
> + .name = "qcom-ramp-controller",
> + .of_match_table = qcom_ramp_controller_match_table,
> + .suppress_bind_attrs = true,
> + },
> + .probe = qcom_ramp_controller_probe,
> + .remove = qcom_ramp_controller_remove,
> +};
> +
> +static int __init qcom_ramp_controller_init(void)
> +{
> + return platform_driver_register(&qcom_ramp_controller_driver);
> +}
> +arch_initcall(qcom_ramp_controller_init);
> +
> +MODULE_AUTHOR("AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>");
> +MODULE_DESCRIPTION("Qualcomm Ramp Controller driver");
> +MODULE_LICENSE("GPL");
--
With best wishes
Dmitry
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