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Date: Fri, 18 May 2018 11:44:20 +0900
From: Chanwoo Choi <cw00.choi@...sung.com>
To: Enric Balletbo i Serra <enric.balletbo@...labora.com>,
MyungJoo Ham <myungjoo.ham@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
Rob Herring <robh+dt@...nel.org>,
Will Deacon <will.deacon@....com>,
Heiko Stuebner <heiko@...ech.de>,
Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...nel.org>,
Sandy Huang <hjc@...k-chips.com>,
David Airlie <airlied@...ux.ie>
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
Derek Basehore <dbasehore@...omium.org>,
linux-clk@...r.kernel.org, linux-rockchip@...ts.infradead.org,
dri-devel@...ts.freedesktop.org, Lin Huang <hl@...k-chips.com>,
kernel@...labora.com, Sean Paul <seanpaul@...omium.org>,
linux-arm-kernel@...ts.infradead.org,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
Elaine Zhang <zhangqing@...k-chips.com>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Jeffy Chen <jeffy.chen@...k-chips.com>
Subject: Re: [RFC PATCH 04/10] devfreq: rk3399_dmc / rockchip: pm_domains:
Register notify to DMC driver.
Hi,
As I already commented[1], I think that it is not proper in order to pass
the devfreq instance to power_domain driver by separate defined function
(rockchip_pm_register_dmcfreq_notifier()).
[1] https://patchwork.kernel.org/patch/10349571/
Maybe, you could check the 'OF graph[1]' or 'device connection[2]'
for the device connection. Unfortunately, I'm not sure what is
best solution for this issue.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/graph.txt
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f2d9b66d84f3ff5ea3aff111e6a403e04fa8bf37
On 2018년 05월 15일 06:16, Enric Balletbo i Serra wrote:
> From: Lin Huang <hl@...k-chips.com>
>
> The DMC (Dynamic Memory Interface) controller does a SiP call to the
> Trusted Firmware-A (TF-A) to change the DDR clock frequency. When this
> happens the TF-A writes to the PMU bus idle request register
> (PMU_BUS_IDLE_REQ) but at the same time it is possible that the Rockchip
> power domain driver writes to the same register. So, add a notification
> mechanism to ensure that the DMC and the PD driver does not access to this
> register at the same time.
>
> Signed-off-by: Lin Huang <hl@...k-chips.com>
> [rewrite commit message]
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> ---
> As I explained in the cover letter I have doubts regarding this patch
> but I did not find another way to do it. So I will appreciate any
> feedback on this.
>
> drivers/devfreq/rk3399_dmc.c | 7 ++++++
> drivers/soc/rockchip/pm_domains.c | 36 +++++++++++++++++++++++++++++++
> include/soc/rockchip/rk3399_dmc.h | 14 ++++++++++++
> 3 files changed, 57 insertions(+)
> create mode 100644 include/soc/rockchip/rk3399_dmc.h
>
> diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
> index cc1bbca3fb15..2c4985a501cb 100644
> --- a/drivers/devfreq/rk3399_dmc.c
> +++ b/drivers/devfreq/rk3399_dmc.c
> @@ -28,6 +28,7 @@
> #include <linux/rwsem.h>
> #include <linux/suspend.h>
>
> +#include <soc/rockchip/rk3399_dmc.h>
> #include <soc/rockchip/rk3399_grf.h>
> #include <soc/rockchip/rockchip_sip.h>
>
> @@ -443,6 +444,12 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
> data->dev = dev;
> platform_set_drvdata(pdev, data);
>
> + rockchip_pm_register_dmcfreq_notifier(data->devfreq);
> + if (ret < 0) {
> + dev_err(dev, "Failed to register dmcfreq notifier\n");
> + return ret;
> + }
> +
> return 0;
> }
>
> diff --git a/drivers/soc/rockchip/pm_domains.c b/drivers/soc/rockchip/pm_domains.c
> index 53efc386b1ad..b0e66f24b3e3 100644
> --- a/drivers/soc/rockchip/pm_domains.c
> +++ b/drivers/soc/rockchip/pm_domains.c
> @@ -8,6 +8,7 @@
> * published by the Free Software Foundation.
> */
>
> +#include <linux/devfreq.h>
> #include <linux/io.h>
> #include <linux/iopoll.h>
> #include <linux/err.h>
> @@ -76,9 +77,13 @@ struct rockchip_pmu {
> const struct rockchip_pmu_info *info;
> struct mutex mutex; /* mutex lock for pmu */
> struct genpd_onecell_data genpd_data;
> + struct devfreq *devfreq;
> + struct notifier_block dmc_nb;
> struct generic_pm_domain *domains[];
> };
>
> +static struct rockchip_pmu *dmc_pmu;
> +
> #define to_rockchip_pd(gpd) container_of(gpd, struct rockchip_pm_domain, genpd)
>
> #define DOMAIN(pwr, status, req, idle, ack, wakeup) \
> @@ -601,6 +606,35 @@ static int rockchip_pm_add_subdomain(struct rockchip_pmu *pmu,
> return error;
> }
>
> +static int rk3399_dmcfreq_notify(struct notifier_block *nb,
> + unsigned long event, void *data)
> +{
> + if (event == DEVFREQ_PRECHANGE)
> + mutex_lock(&dmc_pmu->mutex);
> + else if (event == DEVFREQ_POSTCHANGE)
> + mutex_unlock(&dmc_pmu->mutex);
> +
> + return NOTIFY_OK;
> +}
> +
> +int rockchip_pm_register_dmcfreq_notifier(struct devfreq *devfreq)
> +{
> + int ret;
> +
> + if (!dmc_pmu)
> + return -EPROBE_DEFER;
> +
> + dmc_pmu->devfreq = devfreq;
> + dmc_pmu->dmc_nb.notifier_call = rk3399_dmcfreq_notify;
> + ret = devm_devfreq_register_notifier(devfreq->dev.parent,
> + dmc_pmu->devfreq,
> + &dmc_pmu->dmc_nb,
> + DEVFREQ_TRANSITION_NOTIFIER);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL(rockchip_pm_register_dmcfreq_notifier);
> +
> static int rockchip_pm_domain_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> @@ -694,6 +728,8 @@ static int rockchip_pm_domain_probe(struct platform_device *pdev)
> goto err_out;
> }
>
> + dmc_pmu = pmu;
> +
> return 0;
>
> err_out:
> diff --git a/include/soc/rockchip/rk3399_dmc.h b/include/soc/rockchip/rk3399_dmc.h
> new file mode 100644
> index 000000000000..031a62607f61
> --- /dev/null
> +++ b/include/soc/rockchip/rk3399_dmc.h
> @@ -0,0 +1,14 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2016-2018, Fuzhou Rockchip Electronics Co., Ltd
> + * Author: Lin Huang <hl@...k-chips.com>
> + */
> +
> +#ifndef __SOC_RK3399_DMC_H
> +#define __SOC_RK3399_DMC_H
> +
> +#include <linux/devfreq.h>
> +
> +int rockchip_pm_register_dmcfreq_notifier(struct devfreq *devfreq);
> +
> +#endif
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
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