From: Adam Ford <aford173@gmail.com>
To: Leonard Crestez <leonard.crestez@nxp.com>
Cc: "Jacky Bai" <ping.bai@nxp.com>, "Stephen Boyd" <sboyd@kernel.org>,
"Chanwoo Choi" <cw00.choi@samsung.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"Artur Świgoń" <a.swigon@partner.samsung.com>,
"Viresh Kumar" <viresh.kumar@linaro.org>,
"Michael Turquette" <mturquette@baylibre.com>,
"Angus Ainslie" <angus@akkea.ca>,
"Alexandre Bailon" <abailon@baylibre.com>,
"Matthias Kaehlcke" <mka@chromium.org>,
"Abel Vesa" <abel.vesa@nxp.com>,
"Saravana Kannan" <saravanak@google.com>,
"Krzysztof Kozlowski" <krzk@kernel.org>,
linux-clk <linux-clk@vger.kernel.org>,
"MyungJoo Ham" <myungjoo.ham@samsung.com>,
dl-linux-imx <linux-imx@nxp.com>,
devicetree <devicetree@vger.kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"Martin Kepplinger" <martink@posteo.de>,
"Silvano Di Ninno" <silvano.dininno@nxp.com>,
arm-soc <linux-arm-kernel@lists.infradead.org>,
"Aisheng Dong" <aisheng.dong@nxp.com>,
"Anson Huang" <anson.huang@nxp.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Kyungmin Park" <kyungmin.park@samsung.com>,
"Sascha Hauer" <kernel@pengutronix.de>,
"Fabio Estevam" <fabio.estevam@nxp.com>,
"Shawn Guo" <shawnguo@kernel.org>,
"Georgi Djakov" <georgi.djakov@linaro.org>
Subject: Re: [PATCH v7 0/5] PM / devfreq: Add dynamic scaling for imx8m ddr controller
Date: Wed, 18 Dec 2019 09:37:14 -0600 [thread overview]
Message-ID: <CAHCN7xKHJAb8k1A+WC3EUOmgLTx-Kbjw_5EsmwyhDkkOKCsmGQ@mail.gmail.com> (raw)
In-Reply-To: <VI1PR04MB70235951BC137515BDD2FDC7EE530@VI1PR04MB7023.eurprd04.prod.outlook.com>
On Wed, Dec 18, 2019 at 9:16 AM Leonard Crestez <leonard.crestez@nxp.com> wrote:
>
> On 18.12.2019 17:05, Adam Ford wrote:
> > On Wed, Dec 18, 2019 at 8:44 AM Leonard Crestez <leonard.crestez@nxp.com> wrote:
> >>
> >> On 18.12.2019 15:35, Adam Ford wrote:
> >>> On Fri, Nov 22, 2019 at 3:45 PM Leonard Crestez <leonard.crestez@nxp.com> wrote:
> >>>>
> >>>> This adds support for dynamic scaling of the DDR Controller (ddrc)
> >>>> present on i.MX8M series chips. Actual frequency switching is
> >>>> implemented inside TF-A, this driver wraps the SMC calls and
> >>>> synchronizes the clk tree.
> >>>>
> >>>> DRAM frequency switching requires clock manipulation but during this operation
> >>>> DRAM itself is briefly inaccessible so this operation is performed a SMC call
> >>>> to by TF-A which runs from a SRAM area. Upon returning to linux the clock tree
> >>>> is updated to correspond to hardware configuration.
> >>>>
> >>>> This is handled via CLK_GET_RATE_NO_CACHE for dividers but muxes are handled
> >>>> manually: the driver will prepare/enable the new parents ahead of switching (so
> >>>> that the expected roots are enabled) and afterwards it will call clk_set_parent
> >>>> to ensure the parents in clock framework are up-to-date.
> >>>>
> >>>> This series is useful standalone and roughly similar to devfreq drivers for
> >>>> tegra and rockchip.
> >>>>
> >>>> Running at lower dram rates saves power but can affect the functionality of
> >>>> other blocks in the chip (display, vpu etc). Support for in-kernel constraints
> >>>> will some separately.
> >>>>
> >>>> This series has no dependencies outside linux-next. The driver depends
> >>>> on features from the NXP branch of TF-A and will cleanly fail to probe
> >>>> on mainline. There are also plans to upstream dram dvfs in TF-A.
> >>>>
> >>>> Leonard Crestez (5):
> >>>> clk: imx8m: Set CLK_GET_RATE_NOCACHE on dram clocks
> >>>> clk: imx: Mark dram pll on 8mm and 8mn with CLK_GET_RATE_NOCACHE
> >>>> dt-bindings: memory: Add bindings for imx8m ddr controller
> >>>> PM / devfreq: Add dynamic scaling for imx8m ddr controller
> >>>> arm64: dts: imx8m: Add ddr controller nodes
> >>>>
> >>>> .../memory-controllers/fsl/imx8m-ddrc.yaml | 72 +++
> >>>> arch/arm64/boot/dts/freescale/imx8mm-evk.dts | 18 +
> >>>> arch/arm64/boot/dts/freescale/imx8mm.dtsi | 10 +
> >>>> .../boot/dts/freescale/imx8mn-ddr4-evk.dts | 18 +
> >>>> arch/arm64/boot/dts/freescale/imx8mn.dtsi | 10 +
> >>>> arch/arm64/boot/dts/freescale/imx8mq-evk.dts | 24 +
> >>>> arch/arm64/boot/dts/freescale/imx8mq.dtsi | 10 +
> >>>> drivers/clk/imx/clk-imx8mm.c | 11 +-
> >>>> drivers/clk/imx/clk-imx8mn.c | 12 +-
> >>>> drivers/clk/imx/clk-imx8mq.c | 12 +-
> >>>> drivers/clk/imx/clk-pll14xx.c | 7 +
> >>>> drivers/clk/imx/clk.h | 1 +
> >>>> drivers/devfreq/Kconfig | 9 +
> >>>
> >>> Since there is a Kconfig change, should there me a defconfig change?
> >>
> >> Yes, you need to enable CONFIG_ARM_IMX8M_DDRC_DEVFREQ in order to test
> >> this. Enabling as "m" should work.
> >
> > I enabled it as 'm' but I was more curious to know if we should push
> > this upstream with the rest of the series.
>
> I skipped enabling because it's very experimental; maybe after imx
> interconnect is also enabled?
>
> >>>> drivers/devfreq/Makefile | 1 +
> >>>> drivers/devfreq/imx8m-ddrc.c | 465 ++++++++++++++++++
> >>>> 15 files changed, 670 insertions(+), 10 deletions(-)
> >>>> create mode 100644 Documentation/devicetree/bindings/memory-controllers/fsl/imx8m-ddrc.yaml
> >>>> create mode 100644 drivers/devfreq/imx8m-ddrc.c
> >>>
> >>> I applied the whole series against 5.5-rc1 and I am trying to test it.
> >>> I know the 4.14 kernel NXP posted on Code Aurora is capable to
> >>> lowering the DDRC controller to 25MHz on the 8MM when the video is
> >>> off. Since there is no video support yet for the 8MM, I was expecting
> >>> to see the DDRC clock to be at or around 25MHz.
> >>>
> >>> Using debug FS, I can see the dram core clock is still running at
> >>> 750MHz, and measuring power, it shows something consistent with what I
> >>> see on the Code Aurora kernel with video turned on and the clock at
> >>> 750MHz.
> >>>
> >>> Is there some way to get the dram_core_clk to drop to 25MHz to see
> >>> some power reduction? The same commands used in the Yocto build don't
> >>> apply here since we don't have video.
> >>
> >> Current upstream driver just keeps current frequency by default. Try the
> >> following:
> >>
> >> cd /sys/class/devfreq/devices/devfreq0
> >
> > can't cd to /sys/class/devfreq/devices/devfreq0: No such file or directory
> >
> > I did some checking and I found:
> > imx8m-ddrc-devfreq 3d400000.memory-controller: failed to init
> > firmware freq info: -19
> >
> > Was there some prerequisite patches I needed to apply before your series?
>
> You need a recent version of TF-A from nxp ( upstream). Try this:
>
> https://source.codeaurora.org/external/imx/imx-atf/log/?h=imx_4.19.35_1.1.0
>
> Or this:
> https://github.com/cdleonard/arm-trusted-firmware/commits/imx_2.0.y_busfreq
>
> Support on upstream ATF is not yet available
I cloned your github branch and built it per the instructions in the
u-boot readme file.
did a make clean on u-boot, copied the bl31.bin to u-boot and rebuild
per U-Boot's instructions.
U-Boot booted and Linux booted, but I still get:
imx8m-ddrc-devfreq 3d400000.memory-controller: failed to init
firmware freq info: -19
I am still learning the imx8mm platform, so please forgive my ignorance.
adam
>
> --
> Regards,
> Leonard
next prev parent reply other threads:[~2019-12-18 15:37 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-22 21:44 [PATCH v7 0/5] PM / devfreq: Add dynamic scaling for imx8m ddr controller Leonard Crestez
2019-11-22 21:45 ` [PATCH v7 1/5] clk: imx8m: Set CLK_GET_RATE_NOCACHE on dram clocks Leonard Crestez
2019-12-09 1:15 ` Shawn Guo
2019-11-22 21:45 ` [PATCH v7 2/5] clk: imx: Mark dram pll on 8mm and 8mn with CLK_GET_RATE_NOCACHE Leonard Crestez
2019-12-09 1:16 ` Shawn Guo
2019-11-22 21:45 ` [PATCH v7 3/5] dt-bindings: memory: Add bindings for imx8m ddr controller Leonard Crestez
2019-11-22 21:45 ` [PATCH v7 4/5] PM / devfreq: Add dynamic scaling " Leonard Crestez
2019-11-24 23:59 ` Chanwoo Choi
2019-11-26 19:44 ` Rob Herring
2019-11-26 23:25 ` Chanwoo Choi
[not found] ` <CGME20191219230258epcas1p16ec64c3a06eafd9f0a3784d18541ce5c@epcas1p1.samsung.com>
2019-12-19 23:09 ` [v8 PATCH] " Chanwoo Choi
2019-12-19 23:10 ` Chanwoo Choi
2019-11-22 21:45 ` [PATCH v7 5/5] arm64: dts: imx8m: Add ddr controller nodes Leonard Crestez
2019-11-28 14:43 ` Adam Ford
2019-11-29 5:33 ` Leonard Crestez
2019-12-09 1:34 ` Shawn Guo
2019-12-18 13:35 ` [PATCH v7 0/5] PM / devfreq: Add dynamic scaling for imx8m ddr controller Adam Ford
2019-12-18 14:44 ` Leonard Crestez
2019-12-18 15:05 ` Adam Ford
2019-12-18 15:16 ` Leonard Crestez
2019-12-18 15:37 ` Adam Ford [this message]
2019-12-18 16:22 ` Leonard Crestez
2019-12-18 16:42 ` Adam Ford
[not found] ` <CAHCN7xKjpN_XEGLj-1jMG5mBbF=su67k+10frheLt+L1XaR0-g@mail.gmail.com>
2020-01-13 23:36 ` Leonard Crestez
2020-01-15 20:09 ` Adam Ford
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