Message-ID: <1566178551.6371.6.camel@mtksdaap41>
Date:   Mon, 19 Aug 2019 09:35:51 +0800
From:   Henry Chen <henryc.chen@...iatek.com>
To:     Ryan Case <ryandcase@...omium.org>
CC:     Georgi Djakov <georgi.djakov@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "Viresh Kumar" <vireshk@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        "Nicolas Boichat" <drinkcat@...gle.com>,
        Fan Chen <fan.chen@...iatek.com>,
        James Liao <jamesjj.liao@...iatek.com>,
        Weiyi Lu <weiyi.lu@...iatek.com>, <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [RFC V2 06/11] soc: mediatek: add MT8183 dvfsrc support

On Mon, 2019-06-10 at 14:00 -0700, Ryan Case wrote:
Hi Ryan,

Sorry for late reply.

> Hi Henry,
> 
> On Tue, Apr 30, 2019 at 2:45 AM Henry Chen <henryc.chen@...iatek.com> wrote:
> >
> > Add dvfsrc driver for MT8183
> >
> > Signed-off-by: Henry Chen <henryc.chen@...iatek.com>
> > ---
> >  drivers/soc/mediatek/Kconfig      |  15 ++
> >  drivers/soc/mediatek/Makefile     |   1 +
> >  drivers/soc/mediatek/mtk-dvfsrc.c | 347 ++++++++++++++++++++++++++++++++++++++
> >  include/soc/mediatek/mtk_dvfsrc.h |  22 +++
> >  4 files changed, 385 insertions(+)
> >  create mode 100644 drivers/soc/mediatek/mtk-dvfsrc.c
> >  create mode 100644 include/soc/mediatek/mtk_dvfsrc.h
> >
> > diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
> > index 17bd759..2721fd6 100644
> > --- a/drivers/soc/mediatek/Kconfig
> > +++ b/drivers/soc/mediatek/Kconfig
> > @@ -24,6 +24,21 @@ config MTK_INFRACFG
> >           INFRACFG controller contains various infrastructure registers not
> >           directly associated to any device.
> >
> > +config MTK_DVFSRC
> > +       bool "MediaTek DVFSRC Support"
> > +       depends on ARCH_MEDIATEK
> > +       default ARCH_MEDIATEK
> > +       select MTK_INFRACFG
> > +       select PM_GENERIC_DOMAINS if PM
> > +       depends on MTK_SCPSYS
> > +       help
> > +         Say yes here to add support for the MediaTek DVFSRC (dynamic voltage
> > +         and frequency scaling resource collector) found
> > +         on different MediaTek SoCs. The DVFSRC is a proprietary
> > +         hardware which is used to collect all the requests from
> > +         system and turn into the decision of minimum Vcore voltage
> > +         and minimum DRAM frequency to fulfill those requests.
> > +
> >  config MTK_PMIC_WRAP
> >         tristate "MediaTek PMIC Wrapper Support"
> >         depends on RESET_CONTROLLER
> > diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
> > index b9dbad6..cd9d63f 100644
> > --- a/drivers/soc/mediatek/Makefile
> > +++ b/drivers/soc/mediatek/Makefile
> > @@ -1,4 +1,5 @@
> >  obj-$(CONFIG_MTK_CMDQ) += mtk-cmdq-helper.o
> > +obj-$(CONFIG_MTK_DVFSRC) += mtk-dvfsrc.o
> >  obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o mtk-scpsys-ext.o
> >  obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
> >  obj-$(CONFIG_MTK_SCPSYS) += mtk-scpsys.o
> > diff --git a/drivers/soc/mediatek/mtk-dvfsrc.c b/drivers/soc/mediatek/mtk-dvfsrc.c
> > new file mode 100644
> > index 0000000..e54a654
> > --- /dev/null
> > +++ b/drivers/soc/mediatek/mtk-dvfsrc.c
> > @@ -0,0 +1,347 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2018 MediaTek Inc.
> > + */
> > +#include <linux/arm-smccc.h>
> > +#include <linux/clk.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/notifier.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <soc/mediatek/mtk_dvfsrc.h>
> > +#include <soc/mediatek/mtk_sip.h>
> > +#include <dt-bindings/power/mt8183-power.h>
> > +#include <dt-bindings/soc/mtk,dvfsrc.h>
> > +#include <dt-bindings/soc/mtk,dvfsrc.h>
> > +#include "mtk-scpsys.h"
> > +
> > +#define DVFSRC_IDLE            0x00
> > +#define DVFSRC_GET_TARGET_LEVEL(x)     (((x) >> 0) & 0x0000ffff)
> > +#define DVFSRC_GET_CURRENT_LEVEL(x)    (((x) >> 16) & 0x0000ffff)
> > +
> > +#define MT8183_DVFSRC_OPP_LP4  0
> > +#define MT8183_DVFSRC_OPP_LP4X 1
> > +#define MT8183_DVFSRC_OPP_LP3  2
> > +
> > +struct dvfsrc_opp {
> > +       u32 vcore_opp;
> > +       u32 dram_opp;
> > +};
> > +
> > +struct dvfsrc_domain {
> > +       u32 id;
> > +       u32 state;
> > +};
> > +
> > +struct mtk_dvfsrc;
> > +struct dvfsrc_soc_data {
> > +       const int *regs;
> > +       u32 num_opp;
> > +       u32 num_domains;
> > +       const struct dvfsrc_opp **opps;
> > +       struct dvfsrc_domain *domains;
> > +       int (*get_target_level)(struct mtk_dvfsrc *dvfsrc);
> > +       int (*get_current_level)(struct mtk_dvfsrc *dvfsrc);
> > +       void (*set_dram_bw)(struct mtk_dvfsrc *dvfsrc, u64 bw);
> > +       void (*set_opp_level)(struct mtk_dvfsrc *dvfsrc, u32 level);
> > +};
> > +
> > +struct mtk_dvfsrc {
> > +       struct device *dev;
> > +       struct clk *clk_dvfsrc;
> > +       const struct dvfsrc_soc_data *dvd;
> > +       int dram_type;
> > +       void __iomem *regs;
> > +       struct mutex lock;
> > +       struct notifier_block scpsys_notifier;
> > +};
> > +
> > +static u32 dvfsrc_read(struct mtk_dvfsrc *dvfs, u32 offset)
> > +{
> > +       return readl(dvfs->regs + dvfs->dvd->regs[offset]);
> > +}
> > +
> > +static void dvfsrc_write(struct mtk_dvfsrc *dvfs, u32 offset, u32 val)
> > +{
> > +       writel(val, dvfs->regs + dvfs->dvd->regs[offset]);
> > +}
> > +
> > +enum dvfsrc_regs {
> > +       DVFSRC_SW_REQ,
> > +       DVFSRC_LEVEL,
> > +       DVFSRC_SW_BW_0,
> > +       DVFSRC_LAST,
> > +};
> > +
> > +static const int mt8183_regs[] = {
> > +       [DVFSRC_SW_REQ] =       0x4,
> > +       [DVFSRC_LEVEL] =        0xDC,
> > +       [DVFSRC_SW_BW_0] =      0x160,
> > +       [DVFSRC_LAST] =         0x308,
> > +};
> > +
> > +static bool dvfsrc_is_idle(struct mtk_dvfsrc *dvfsrc)
> > +{
> > +       if (!dvfsrc->dvd->get_target_level)
> > +               return true;
> > +
> > +       return dvfsrc->dvd->get_target_level(dvfsrc) == DVFSRC_IDLE;
> > +}
> > +
> > +static int dvfsrc_wait_for_idle(struct mtk_dvfsrc *dvfsrc)
> > +{
> > +       unsigned long timeout;
> > +
> > +       timeout = jiffies + usecs_to_jiffies(1000);
> > +
> > +       do {
> > +               if (dvfsrc_is_idle(dvfsrc))
> > +                       return 0;
> > +       } while (!time_after(jiffies, timeout));
> 
> This all seems like it would be better handled by readx_poll_timeout
> rather than rolling your own.
It's great suggestion, thanks.
> 
> > +
> > +       return -ETIMEDOUT;
> > +}
> > +
> > +static int mt8183_get_target_level(struct mtk_dvfsrc *dvfsrc)
> > +{
> > +       return DVFSRC_GET_TARGET_LEVEL(dvfsrc_read(dvfsrc, DVFSRC_LEVEL));
> > +}
> > +
> > +static int mt8183_get_current_level(struct mtk_dvfsrc *dvfsrc)
> > +{
> > +       return ffs(DVFSRC_GET_CURRENT_LEVEL(dvfsrc_read(dvfsrc, DVFSRC_LEVEL)));
> > +}
> > +
> > +static void mt8183_set_dram_bw(struct mtk_dvfsrc *dvfsrc, u64 bw)
> > +{
> > +       dvfsrc_write(dvfsrc, DVFSRC_SW_BW_0, bw);
> > +}
> > +
> > +static void mt8183_set_opp_level(struct mtk_dvfsrc *dvfsrc, u32 level)
> > +{
> > +       int vcore_opp, dram_opp;
> > +       const struct dvfsrc_opp *opp;
> > +
> > +       /* translate pstate to dvfsrc level, and set it to DVFSRC HW */
> > +       opp = &dvfsrc->dvd->opps[dvfsrc->dram_type][level - 1];
> > +       vcore_opp = opp->vcore_opp;
> > +       dram_opp = opp->dram_opp;
> > +
> > +       dev_dbg(dvfsrc->dev, "vcore_opp: %d, dram_opp: %d\n",
> > +               vcore_opp, dram_opp);
> > +       dvfsrc_write(dvfsrc, DVFSRC_SW_REQ, dram_opp | vcore_opp << 2);
> > +}
> > +
> > +void mtk_dvfsrc_send_request(const struct device *dev, u32 cmd, u64 data)
> > +{
> > +       struct mtk_dvfsrc *dvfsrc = dev_get_drvdata(dev);
> > +
> > +       dev_dbg(dvfsrc->dev, "cmd: %d, data: %llu\n", cmd, data);
> > +
> > +       mutex_lock(&dvfsrc->lock);
> > +
> > +       if (dvfsrc_wait_for_idle(dvfsrc)) {
> > +               dev_warn(dvfsrc->dev, "[%s] wait idle, last: %d -> %d\n",
> > +                        __func__, dvfsrc_read(dvfsrc, DVFSRC_LEVEL),
> > +               dvfsrc_read(dvfsrc, DVFSRC_LAST));
> > +               goto out;
> > +       }
> > +
> > +       switch (cmd) {
> > +       case MTK_DVFSRC_CMD_BW_REQUEST:
> > +               dvfsrc->dvd->set_dram_bw(dvfsrc, data);
> > +               goto out;
> > +       case MTK_DVFSRC_CMD_OPP_REQUEST:
> > +               dvfsrc->dvd->set_opp_level(dvfsrc, data);
> > +               break;
> > +       default:
> > +               dev_err(dvfsrc->dev, "unknown command: %d\n", cmd);
> > +               break;
> > +       }
> > +
> > +       if (dvfsrc_wait_for_idle(dvfsrc)) {
> > +               dev_warn(dvfsrc->dev, "[%s] wait idle, last: %d -> %d\n",
> > +                        __func__, dvfsrc_read(dvfsrc, DVFSRC_LEVEL),
> > +                        dvfsrc_read(dvfsrc, DVFSRC_LAST));
> > +               goto out;
> > +       }
> > +
> > +out:
> > +       mutex_unlock(&dvfsrc->lock);
> > +}
> > +EXPORT_SYMBOL(mtk_dvfsrc_send_request);
> > +
> > +static int dvfsrc_set_performance(struct notifier_block *b,
> > +                                 unsigned long l, void *v)
> > +{
> > +       int i, val, highest;
> 
> Variable names could be improved. "val" is only ever used to store the
> current level, would be nice to make the name more specific. Similarly
> "l" looks like it would be better as something state related.
> 
> val and highest at least should be u32.
ok, about naming, I will correct and make it more clearly.
> 
> > +       struct mtk_dvfsrc *dvfsrc;
> > +       struct scp_event_data *sc = v;
> > +       struct dvfsrc_domain *d;
> > +
> > +       if (sc->event_type != MTK_SCPSYS_PSTATE)
> > +               return 0;
> > +
> > +       dvfsrc = container_of(b, struct mtk_dvfsrc, scpsys_notifier);
> > +
> > +       d = dvfsrc->dvd->domains;
> > +
> > +       if (l > dvfsrc->dvd->num_opp) {
> > +               dev_err(dvfsrc->dev, "pstate out of range = %ld\n", l);
> > +               goto out;
> 
> Can just return 0;
ok.
> 
> > +       }
> > +
> > +       for (i = 0, highest = 0; i < dvfsrc->dvd->num_domains - 1; i++, d++) {
> 
> It's not immediately clear to me why a domain is skipped (the -1).
> This is either worth a comment or it may be a bug?
Indeed, it no need, I will check and re-test again, thanks.
> 
> > +               if (sc->domain_id == d->id)
> > +                       d->state = l;
> > +               if (d->state > highest)
> > +                       highest = d->state;
> > +       }
> > +
> > +       if (highest == 0) {
> > +               dev_err(dvfsrc->dev, "domain not match\n");
> 
> This text is incorrect. You're checking whether all domains had a
> state of zero, not whether you found a domain match. Is this check
> actually needed?
I intend to check if the domain match or no. To avoid confusing, I will
re-write it and used flag to check it.
> 
> > +               goto out;
> 
> return 0;
ok.
> 
> > +       }
> > +
> > +       mtk_dvfsrc_send_request(dvfsrc->dev, MTK_DVFSRC_CMD_OPP_REQUEST,
> > +                               highest);
> > +
> > +       val = dvfsrc->dvd->get_current_level(dvfsrc);
> > +
> > +       dev_dbg(dvfsrc->dev, "DVFSRC_LEVEL: %x, val: %x, DVFSRC_SW_REQ: %x\n",
> > +               dvfsrc_read(dvfsrc, DVFSRC_LEVEL), val,
> > +               dvfsrc_read(dvfsrc, DVFSRC_SW_REQ));
> 
> "val:" to "current level:" or something similarly descriptive.
ok.
> 
> > +
> > +       if (val < highest) {
> > +               dev_err(dvfsrc->dev, "current: %d < highest: %x\n",
> > +                       val, highest);
> 
> This message isn't clear and should be more explicit. Something like
> "Current level %d < highest requested %d"
> 
> > +               goto out;
> 
> return 0;
ok.
> 
> > +       }
> > +
> > +out:
> 
> Out label no longer needed.
ok.
> 
> > +       return 0;
> > +}
> > +
> > +static void pstate_notifier_register(struct mtk_dvfsrc *dvfsrc)
> > +{
> > +       dvfsrc->scpsys_notifier.notifier_call = dvfsrc_set_performance;
> > +       register_scpsys_notifier(&dvfsrc->scpsys_notifier);
> > +}
> > +
> > +static int mtk_dvfsrc_probe(struct platform_device *pdev)
> > +{
> > +       struct arm_smccc_res ares;
> > +       struct resource *res;
> > +       struct mtk_dvfsrc *dvfsrc;
> > +       int ret;
> > +
> > +       dvfsrc = devm_kzalloc(&pdev->dev, sizeof(*dvfsrc), GFP_KERNEL);
> > +       if (!dvfsrc)
> > +               return -ENOMEM;
> > +
> > +       dvfsrc->dvd = of_device_get_match_data(&pdev->dev);
> > +       dvfsrc->dev = &pdev->dev;
> > +
> > +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +       dvfsrc->regs = devm_ioremap_resource(&pdev->dev, res);
> > +       if (IS_ERR(dvfsrc->regs))
> > +               return PTR_ERR(dvfsrc->regs);
> > +
> > +       dvfsrc->clk_dvfsrc = devm_clk_get(dvfsrc->dev, "dvfsrc");
> > +       if (IS_ERR(dvfsrc->clk_dvfsrc)) {
> > +               dev_err(dvfsrc->dev, "failed to get clock: %ld\n",
> > +                       PTR_ERR(dvfsrc->clk_dvfsrc));
> > +               return PTR_ERR(dvfsrc->clk_dvfsrc);
> > +       }
> > +
> > +       ret = clk_prepare_enable(dvfsrc->clk_dvfsrc);
> > +       if (ret)
> > +               return ret;
> > +
> > +       mutex_init(&dvfsrc->lock);
> > +
> > +       arm_smccc_smc(MTK_SIP_SPM, MTK_SIP_SPM_DVFSRC_INIT, 0, 0, 0, 0, 0, 0,
> > +                     &ares);
> > +
> > +       if (!ares.a0) {
> > +               dvfsrc->dram_type = ares.a1;
> > +       } else {
> > +               dev_err(dvfsrc->dev, "init fails: %lu\n", ares.a0);
> > +               clk_disable_unprepare(dvfsrc->clk_dvfsrc);
> > +               return ares.a0;
> > +       }
> > +
> > +       platform_set_drvdata(pdev, dvfsrc);
> > +       pstate_notifier_register(dvfsrc);
> > +
> > +       return devm_of_platform_populate(&pdev->dev);
> > +}
> > +
> > +static const struct dvfsrc_opp dvfsrc_opp_mt8183_lp4[] = {
> > +       {0, 0}, {0, 1}, {0, 2}, {1, 2},
> > +};
> > +
> > +static const struct dvfsrc_opp dvfsrc_opp_mt8183_lp3[] = {
> > +       {0, 0}, {0, 1}, {1, 1}, {1, 2},
> > +};
> > +
> > +static const struct dvfsrc_opp *dvfsrc_opp_mt8183[] = {
> > +       [MT8183_DVFSRC_OPP_LP4] = dvfsrc_opp_mt8183_lp4,
> > +       [MT8183_DVFSRC_OPP_LP4X] = dvfsrc_opp_mt8183_lp3,
> > +       [MT8183_DVFSRC_OPP_LP3] = dvfsrc_opp_mt8183_lp3,
> > +};
> > +
> > +static struct dvfsrc_domain dvfsrc_domains_mt8183[] = {
> > +       { MT8183_POWER_DOMAIN_MFG_ASYNC, 0 },
> > +       { MT8183_POWER_DOMAIN_MFG, 0 },
> > +       { MT8183_POWER_DOMAIN_CAM, 0 },
> > +       { MT8183_POWER_DOMAIN_DISP, 0 },
> > +       { MT8183_POWER_DOMAIN_ISP, 0 },
> > +       { MT8183_POWER_DOMAIN_VDEC, 0 },
> > +       { MT8183_POWER_DOMAIN_VENC, 0 },
> > +};
> > +
> > +static const struct dvfsrc_soc_data mt8183_data = {
> > +       .opps = dvfsrc_opp_mt8183,
> > +       .num_opp = ARRAY_SIZE(dvfsrc_opp_mt8183_lp4),
> > +       .regs = mt8183_regs,
> > +       .domains = dvfsrc_domains_mt8183,
> > +       .num_domains = ARRAY_SIZE(dvfsrc_domains_mt8183),
> > +       .get_target_level = mt8183_get_target_level,
> > +       .get_current_level = mt8183_get_current_level,
> > +       .set_dram_bw = mt8183_set_dram_bw,
> > +       .set_opp_level = mt8183_set_opp_level,
> > +};
> > +
> > +static int mtk_dvfsrc_remove(struct platform_device *pdev)
> > +{
> > +       struct mtk_dvfsrc *dvfsrc = platform_get_drvdata(pdev);
> > +
> > +       clk_disable_unprepare(dvfsrc->clk_dvfsrc);
> > +
> > +       return 0;
> > +}
> > +
> > +static const struct of_device_id mtk_dvfsrc_of_match[] = {
> > +       {
> > +               .compatible = "mediatek,mt8183-dvfsrc",
> > +               .data = &mt8183_data,
> > +       }, {
> > +               /* sentinel */
> > +       },
> > +};
> > +
> > +static struct platform_driver mtk_dvfsrc_driver = {
> > +       .probe  = mtk_dvfsrc_probe,
> > +       .remove = mtk_dvfsrc_remove,
> > +       .driver = {
> > +               .name = "mtk-dvfsrc",
> > +               .of_match_table = of_match_ptr(mtk_dvfsrc_of_match),
> > +       },
> > +};
> > +
> > +builtin_platform_driver(mtk_dvfsrc_driver);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_DESCRIPTION("MTK DVFSRC driver");
> > diff --git a/include/soc/mediatek/mtk_dvfsrc.h b/include/soc/mediatek/mtk_dvfsrc.h
> > new file mode 100644
> > index 0000000..e759a65
> > --- /dev/null
> > +++ b/include/soc/mediatek/mtk_dvfsrc.h
> > @@ -0,0 +1,22 @@
> > +/* SPDX-License-Identifier: GPL-2.0
> > + *
> > + * Copyright (c) 2018 MediaTek Inc.
> > + */
> > +#ifndef __SOC_MTK_DVFSRC_H
> > +#define __SOC_MTK_DVFSRC_H
> > +
> > +#define MTK_DVFSRC_CMD_BW_REQUEST      0
> > +#define MTK_DVFSRC_CMD_OPP_REQUEST     1
> > +
> > +#if IS_ENABLED(CONFIG_MTK_DVFSRC)
> > +void mtk_dvfsrc_send_request(const struct device *dev, u32 cmd, u64 data);
> > +
> > +#else
> > +
> > +static inline void mtk_dvfsrc_send_request(const struct device *dev, u32 cmd,
> > +                                          u64 data)
> > +{ return -ENODEV; }
> > +
> > +#endif /* CONFIG_MTK_DVFSRC */
> > +
> > +#endif
> > --
> > 1.9.1
> >

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