[PATCH v2 0/4] ARM: da850: enable cpufreq in DT mode

[PATCH v2 0/4] ARM: da850: enable cpufreq in DT mode

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

This series adds cpufreq-dt operating points for da850 boards supported
with device tree (da850-lcdk, da850-lego-ev3, da850-evm) and also
includes a fix for the da850-evm boardfile which checks an unset variable
to determine the highest available frequency for cpufreq.

Last patch enables CPUFREQ_DT in davinci_all_defconfig.

v1 -> v2:
- use the VDCDC3_1.2V regulator as cpu-supply on da850-evm

Bartosz Golaszewski (2):
  ARM: davinci: fix cpufreq registration on da850-evm
  ARM: dts: da850-evm: enable cpufreq

David Lechner (2):
  ARM: dts: da850: add cpu node and operating points to DT
  ARM: davinci_all_defconfig: Enable CPUFREQ_DT

 arch/arm/boot/dts/da850-evm.dts         | 12 ++++++
 arch/arm/boot/dts/da850-lcdk.dts        | 31 ++++++++++++++
 arch/arm/boot/dts/da850-lego-ev3.dts    | 30 +++++++++++++
 arch/arm/boot/dts/da850.dtsi            | 56 +++++++++++++++++++++++++
 arch/arm/configs/davinci_all_defconfig  |  1 +
 arch/arm/mach-davinci/board-da850-evm.c | 12 +-----
 6 files changed, 131 insertions(+), 11 deletions(-)

-- 
2.20.1

[PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

The system_rev variable is never set on davinci and is always 0, so
we're using the default max operating point of 300MHz. The cvdd supply
comes from the tps6507 pmic and the voltage can go all the way to 1.3V
so the maximum supported rate should be 456MHz.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 arch/arm/mach-davinci/board-da850-evm.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/arch/arm/mach-davinci/board-da850-evm.c b/arch/arm/mach-davinci/board-da850-evm.c
index 1fdc9283a8c5..58b2a485b527 100644
--- a/arch/arm/mach-davinci/board-da850-evm.c
+++ b/arch/arm/mach-davinci/board-da850-evm.c
@@ -1155,17 +1155,7 @@ static struct edma_rsv_info *da850_edma_rsv[2] = {
 #ifdef CONFIG_CPU_FREQ
 static __init int da850_evm_init_cpufreq(void)
 {
-	switch (system_rev & 0xF) {
-	case 3:
-		da850_max_speed = 456000;
-		break;
-	case 2:
-		da850_max_speed = 408000;
-		break;
-	case 1:
-		da850_max_speed = 372000;
-		break;
-	}
+	da850_max_speed = 456000;
 
 	return da850_register_cpufreq("pll0_sysclk3");
 }
-- 
2.20.1

[PATCH v2 2/4] ARM: dts: da850: add cpu node and operating points to DT

[Bartosz Golaszewski]

From: David Lechner <david@lechnology.com>

This adds a cpu node and operating points to the common da850.dtsi file.

Additionally, a regulator is added to the LEGO EV3 board along with
some board-specific CPU configuration.

Regulators need to be hooked up on other boards to get them working.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 arch/arm/boot/dts/da850-lcdk.dts     | 31 +++++++++++++++
 arch/arm/boot/dts/da850-lego-ev3.dts | 30 +++++++++++++++
 arch/arm/boot/dts/da850.dtsi         | 56 ++++++++++++++++++++++++++++
 3 files changed, 117 insertions(+)

diff --git a/arch/arm/boot/dts/da850-lcdk.dts b/arch/arm/boot/dts/da850-lcdk.dts
index 26f453dc8370..f29ed9010812 100644
--- a/arch/arm/boot/dts/da850-lcdk.dts
+++ b/arch/arm/boot/dts/da850-lcdk.dts
@@ -155,12 +155,43 @@
 			};
 		};
 	};
+
+	cvdd: regulator0 {
+		compatible = "regulator-fixed";
+		regulator-name = "cvdd";
+		regulator-min-microvolt = <1300000>;
+		regulator-max-microvolt = <1300000>;
+		regulator-always-on;
+		regulator-boot-on;
+	};
 };
 
 &ref_clk {
 	clock-frequency = <24000000>;
 };
 
+&cpu {
+	cpu-supply = <&cvdd>;
+};
+
+/* LCDK has a fixed CVDD of 1.3V, so only op points >= 300MHz are valid */
+
+&opp_100 {
+	status = "disabled";
+};
+
+&opp_200 {
+	status = "disabled";
+};
+
+&opp_375 {
+	status = "okay";
+};
+
+&opp_456 {
+	status = "okay";
+};
+
 &pmx_core {
 	status = "okay";
 
diff --git a/arch/arm/boot/dts/da850-lego-ev3.dts b/arch/arm/boot/dts/da850-lego-ev3.dts
index 66fcadf0ba91..553717f84483 100644
--- a/arch/arm/boot/dts/da850-lego-ev3.dts
+++ b/arch/arm/boot/dts/da850-lego-ev3.dts
@@ -125,6 +125,15 @@
 		amp-supply = <&amp>;
 	};
 
+	cvdd: regulator0 {
+		compatible = "regulator-fixed";
+		regulator-name = "cvdd";
+		regulator-min-microvolt = <1200000>;
+		regulator-max-microvolt = <1200000>;
+		regulator-always-on;
+		regulator-boot-on;
+	};
+
 	/*
 	 * This is a 5V current limiting regulator that is shared by USB,
 	 * the sensor (input) ports, the motor (output) ports and the A/DC.
@@ -204,6 +213,27 @@
 	clock-frequency = <24000000>;
 };
 
+&cpu {
+	cpu-supply = <&cvdd>;
+};
+
+/* since we have a fixed regulator, we can't run at these points */
+&opp_100 {
+	status = "disabled";
+};
+
+&opp_200 {
+	status = "disabled";
+};
+
+/*
+ * The SoC is actually the 456MHz version, but because of the fixed regulator
+ * This is the fastest we can go.
+ */
+&opp_375 {
+	status = "okay";
+};
+
 &pmx_core {
 	status = "okay";
 
diff --git a/arch/arm/boot/dts/da850.dtsi b/arch/arm/boot/dts/da850.dtsi
index 559659b399d0..ee61d1253b58 100644
--- a/arch/arm/boot/dts/da850.dtsi
+++ b/arch/arm/boot/dts/da850.dtsi
@@ -20,6 +20,62 @@
 		reg = <0xc0000000 0x0>;
 	};
 
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu: cpu@0 {
+			compatible = "arm,arm926ej-s";
+			device_type = "cpu";
+			reg = <0>;
+			clocks = <&psc0 14>;
+			operating-points-v2 = <&opp_table>;
+		};
+	};
+
+	opp_table: opp-table {
+		compatible = "operating-points-v2";
+
+		opp_100: opp100-100000000 {
+			opp-hz = /bits/ 64 <100000000>;
+			opp-microvolt = <1000000 950000 1050000>;
+		};
+
+		opp_200: opp110-200000000 {
+			opp-hz = /bits/ 64 <200000000>;
+			opp-microvolt = <1100000 1050000 1160000>;
+		};
+
+		opp_300: opp120-300000000 {
+			opp-hz = /bits/ 64 <300000000>;
+			opp-microvolt = <1200000 1140000 1320000>;
+		};
+
+		/*
+		 * Original silicon was 300MHz max, so higher frequencies
+		 * need to be enabled on a per-board basis if the chip is
+		 * capable.
+		 */
+
+		opp_375: opp120-375000000 {
+			status = "disabled";
+			opp-hz = /bits/ 64 <375000000>;
+			opp-microvolt = <1200000 1140000 1320000>;
+		};
+
+		opp_415: opp130-415000000 {
+			status = "disabled";
+			opp-hz = /bits/ 64 <415000000>;
+			opp-microvolt = <1300000 1250000 1350000>;
+		};
+
+		opp_456: opp130-456000000 {
+			status = "disabled";
+			opp-hz = /bits/ 64 <456000000>;
+			opp-microvolt = <1300000 1250000 1350000>;
+		};
+	};
+
 	arm {
 		#address-cells = <1>;
 		#size-cells = <1>;
-- 
2.20.1

[PATCH v2 3/4] ARM: dts: da850-evm: enable cpufreq

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Enable cpufreq-dt support for da850-evm. The cvdd is supplied by the
tps6507 pmic with configurable output voltage, so all operating points
can be enabled.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 arch/arm/boot/dts/da850-evm.dts | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm/boot/dts/da850-evm.dts b/arch/arm/boot/dts/da850-evm.dts
index f04bc3e15332..a0a1b3dccf37 100644
--- a/arch/arm/boot/dts/da850-evm.dts
+++ b/arch/arm/boot/dts/da850-evm.dts
@@ -191,6 +191,18 @@
 	};
 };
 
+&cpu {
+	cpu-supply = <&vdcdc3_reg>;
+};
+
+&opp_375 {
+	status = "okay";
+};
+
+&opp_456 {
+	status = "okay";
+};
+
 &sata {
 	status = "okay";
 };
-- 
2.20.1

[PATCH v2 4/4] ARM: davinci_all_defconfig: Enable CPUFREQ_DT

[Bartosz Golaszewski]

From: David Lechner <david@lechnology.com>

This sets CONFIG_CPUFREQ_DT=m in davinci_all_defconfig. This is used for
frequency scaling on device tree boards.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 arch/arm/configs/davinci_all_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/configs/davinci_all_defconfig b/arch/arm/configs/davinci_all_defconfig
index 207962a656a2..c3502236132e 100644
--- a/arch/arm/configs/davinci_all_defconfig
+++ b/arch/arm/configs/davinci_all_defconfig
@@ -45,6 +45,7 @@ CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y
 CONFIG_CPU_FREQ_GOV_PERFORMANCE=m
 CONFIG_CPU_FREQ_GOV_POWERSAVE=m
 CONFIG_CPU_FREQ_GOV_ONDEMAND=m
+CONFIG_CPUFREQ_DT=m
 CONFIG_CPU_IDLE=y
 CONFIG_NET=y
 CONFIG_PACKET=y
-- 
2.20.1

Re: [PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm

[Adam Ford]

On Fri, Mar 22, 2019 at 8:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>
> The system_rev variable is never set on davinci and is always 0, so
> we're using the default max operating point of 300MHz. The cvdd supply
> comes from the tps6507 pmic and the voltage can go all the way to 1.3V
> so the maximum supported rate should be 456MHz.

My understanding is that only certain revisions of the silicon can go
to 456MHz.   The L138's Datasheet lists both a 456 and 375 version.  I
cannot find a way to read a register to determine which version of the
silicon is available. Maybe Sekhar can confirm.

adam
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>  arch/arm/mach-davinci/board-da850-evm.c | 12 +-----------
>  1 file changed, 1 insertion(+), 11 deletions(-)
>
> diff --git a/arch/arm/mach-davinci/board-da850-evm.c b/arch/arm/mach-davinci/board-da850-evm.c
> index 1fdc9283a8c5..58b2a485b527 100644
> --- a/arch/arm/mach-davinci/board-da850-evm.c
> +++ b/arch/arm/mach-davinci/board-da850-evm.c
> @@ -1155,17 +1155,7 @@ static struct edma_rsv_info *da850_edma_rsv[2] = {
>  #ifdef CONFIG_CPU_FREQ
>  static __init int da850_evm_init_cpufreq(void)
>  {
> -       switch (system_rev & 0xF) {
> -       case 3:
> -               da850_max_speed = 456000;
> -               break;
> -       case 2:
> -               da850_max_speed = 408000;
> -               break;
> -       case 1:
> -               da850_max_speed = 372000;
> -               break;
> -       }
> +       da850_max_speed = 456000;
>
>         return da850_register_cpufreq("pll0_sysclk3");
>  }
> --
> 2.20.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v2 3/4] ARM: dts: da850-evm: enable cpufreq

[Adam Ford]

On Fri, Mar 22, 2019 at 8:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>
> Enable cpufreq-dt support for da850-evm. The cvdd is supplied by the
> tps6507 pmic with configurable output voltage, so all operating points
> can be enabled.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>  arch/arm/boot/dts/da850-evm.dts | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/arch/arm/boot/dts/da850-evm.dts b/arch/arm/boot/dts/da850-evm.dts
> index f04bc3e15332..a0a1b3dccf37 100644
> --- a/arch/arm/boot/dts/da850-evm.dts
> +++ b/arch/arm/boot/dts/da850-evm.dts
> @@ -191,6 +191,18 @@
>         };
>  };
>
> +&cpu {
> +       cpu-supply = <&vdcdc3_reg>;
> +};
> +
> +&opp_375 {
> +       status = "okay";
> +};
> +
> +&opp_456 {
> +       status = "okay";
> +};

I pulled part number for the processor used in the da850evm that Logic
PD produces, and it shows a imit of 375MHz.  I cross-referenced the
processor part number with the description from a distributor, and the
part number also lists 375MHz, so I think we should leave 456
disabled.

adam
> +
>  &sata {
>         status = "okay";
>  };
> --
> 2.20.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm

[Bartosz Golaszewski]

wt., 26 mar 2019 o 15:00 Adam Ford <aford173@gmail.com> napisał(a):
>
> On Fri, Mar 22, 2019 at 8:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> >
> > From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> >
> > The system_rev variable is never set on davinci and is always 0, so
> > we're using the default max operating point of 300MHz. The cvdd supply
> > comes from the tps6507 pmic and the voltage can go all the way to 1.3V
> > so the maximum supported rate should be 456MHz.
>
> My understanding is that only certain revisions of the silicon can go
> to 456MHz.   The L138's Datasheet lists both a 456 and 375 version.  I
> cannot find a way to read a register to determine which version of the
> silicon is available. Maybe Sekhar can confirm.
>

Commit 28bd2c341120 ("davinci: am18x/da850/omap-l138 evm: add support
for higher speed grades") mentions the following:

---
U-Boot on the EVM sets up ATAG_REVISION to inform the OS
regarding the speed grade supported by the silicon. We use
this information to pass on the speed grade information to
the SoC code.
---

Should the system_rev somehow reflect that revision? Any way I can check it?

Bart

> adam
> >
> > Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > ---
> >  arch/arm/mach-davinci/board-da850-evm.c | 12 +-----------
> >  1 file changed, 1 insertion(+), 11 deletions(-)
> >
> > diff --git a/arch/arm/mach-davinci/board-da850-evm.c b/arch/arm/mach-davinci/board-da850-evm.c
> > index 1fdc9283a8c5..58b2a485b527 100644
> > --- a/arch/arm/mach-davinci/board-da850-evm.c
> > +++ b/arch/arm/mach-davinci/board-da850-evm.c
> > @@ -1155,17 +1155,7 @@ static struct edma_rsv_info *da850_edma_rsv[2] = {
> >  #ifdef CONFIG_CPU_FREQ
> >  static __init int da850_evm_init_cpufreq(void)
> >  {
> > -       switch (system_rev & 0xF) {
> > -       case 3:
> > -               da850_max_speed = 456000;
> > -               break;
> > -       case 2:
> > -               da850_max_speed = 408000;
> > -               break;
> > -       case 1:
> > -               da850_max_speed = 372000;
> > -               break;
> > -       }
> > +       da850_max_speed = 456000;
> >
> >         return da850_register_cpufreq("pll0_sysclk3");
> >  }
> > --
> > 2.20.1
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm

[Sekhar Nori]

Hi Bart,

On 26/03/19 11:21 PM, Bartosz Golaszewski wrote:
> wt., 26 mar 2019 o 15:00 Adam Ford <aford173@gmail.com> napisał(a):
>>
>> On Fri, Mar 22, 2019 at 8:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>>>
>>> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>>>
>>> The system_rev variable is never set on davinci and is always 0, so
>>> we're using the default max operating point of 300MHz. The cvdd supply
>>> comes from the tps6507 pmic and the voltage can go all the way to 1.3V
>>> so the maximum supported rate should be 456MHz.
>>
>> My understanding is that only certain revisions of the silicon can go
>> to 456MHz.   The L138's Datasheet lists both a 456 and 375 version.  I
>> cannot find a way to read a register to determine which version of the
>> silicon is available. Maybe Sekhar can confirm.
>>
> 
> Commit 28bd2c341120 ("davinci: am18x/da850/omap-l138 evm: add support
> for higher speed grades") mentions the following:
> 
> ---
> U-Boot on the EVM sets up ATAG_REVISION to inform the OS
> regarding the speed grade supported by the silicon. We use
> this information to pass on the speed grade information to
> the SoC code.
> ---
> 
> Should the system_rev somehow reflect that revision? Any way I can check it?

Can you check if the procedure in doc/README.davinci in U-Boot sources 
still works?

Environment Variables
=====================

The DA850 EVM allows the user to specify the maximum cpu clock allowed by the
silicon, in Hz, via an environment variable "maxcpuclk".

The maximum clock rate allowed depends on the silicon populated on the EVM.
Please make sure you understand the restrictions placed on this clock in the
device specific datasheet before setting up this variable. This information is
passed to the Linux kernel using the ATAG_REVISION atag.

If "maxcpuclk" is not defined, the configuration CONFIG_DA850_EVM_MAX_CPU_CLK
is used to obtain this information.

Thanks,
Sekhar

Re: [PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm

[Bartosz Golaszewski]

śr., 27 mar 2019 o 12:14 Sekhar Nori <nsekhar@ti.com> napisał(a):
>
> Hi Bart,
>
> On 26/03/19 11:21 PM, Bartosz Golaszewski wrote:
> > wt., 26 mar 2019 o 15:00 Adam Ford <aford173@gmail.com> napisał(a):
> >>
> >> On Fri, Mar 22, 2019 at 8:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> >>>
> >>> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> >>>
> >>> The system_rev variable is never set on davinci and is always 0, so
> >>> we're using the default max operating point of 300MHz. The cvdd supply
> >>> comes from the tps6507 pmic and the voltage can go all the way to 1.3V
> >>> so the maximum supported rate should be 456MHz.
> >>
> >> My understanding is that only certain revisions of the silicon can go
> >> to 456MHz.   The L138's Datasheet lists both a 456 and 375 version.  I
> >> cannot find a way to read a register to determine which version of the
> >> silicon is available. Maybe Sekhar can confirm.
> >>
> >
> > Commit 28bd2c341120 ("davinci: am18x/da850/omap-l138 evm: add support
> > for higher speed grades") mentions the following:
> >
> > ---
> > U-Boot on the EVM sets up ATAG_REVISION to inform the OS
> > regarding the speed grade supported by the silicon. We use
> > this information to pass on the speed grade information to
> > the SoC code.
> > ---
> >
> > Should the system_rev somehow reflect that revision? Any way I can check it?
>
> Can you check if the procedure in doc/README.davinci in U-Boot sources
> still works?
>
> Environment Variables
> =====================
>
> The DA850 EVM allows the user to specify the maximum cpu clock allowed by the
> silicon, in Hz, via an environment variable "maxcpuclk".
>
> The maximum clock rate allowed depends on the silicon populated on the EVM.
> Please make sure you understand the restrictions placed on this clock in the
> device specific datasheet before setting up this variable. This information is
> passed to the Linux kernel using the ATAG_REVISION atag.
>
> If "maxcpuclk" is not defined, the configuration CONFIG_DA850_EVM_MAX_CPU_CLK
> is used to obtain this information.
>
> Thanks,
> Sekhar

Hi Sekhar,

I built the current upstream u-boot and the get_board_rev() function
for da850-evm doesn't seem to be called at all. For instance the
lego-ev3 platform does this:

./lego/ev3/legoev3.c:108: board_rev = get_board_rev();

but in davinci this function seems to be unused and I don't see it
called from any other core u-boot component. I don't see any commit
that would mention this function but there are a lot of commits
removing get_board_rev() for other boards in git log. Is it possible
it stopped being used at some point?

Bart

Re: [PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm

[Adam Ford]

On Wed, Apr 3, 2019 at 7:50 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> śr., 27 mar 2019 o 12:14 Sekhar Nori <nsekhar@ti.com> napisał(a):
> >
> > Hi Bart,
> >
> > On 26/03/19 11:21 PM, Bartosz Golaszewski wrote:
> > > wt., 26 mar 2019 o 15:00 Adam Ford <aford173@gmail.com> napisał(a):
> > >>
> > >> On Fri, Mar 22, 2019 at 8:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> > >>>
> > >>> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > >>>
> > >>> The system_rev variable is never set on davinci and is always 0, so
> > >>> we're using the default max operating point of 300MHz. The cvdd supply
> > >>> comes from the tps6507 pmic and the voltage can go all the way to 1.3V
> > >>> so the maximum supported rate should be 456MHz.
> > >>
> > >> My understanding is that only certain revisions of the silicon can go
> > >> to 456MHz.   The L138's Datasheet lists both a 456 and 375 version.  I
> > >> cannot find a way to read a register to determine which version of the
> > >> silicon is available. Maybe Sekhar can confirm.
> > >>
> > >
> > > Commit 28bd2c341120 ("davinci: am18x/da850/omap-l138 evm: add support
> > > for higher speed grades") mentions the following:
> > >
> > > ---
> > > U-Boot on the EVM sets up ATAG_REVISION to inform the OS
> > > regarding the speed grade supported by the silicon. We use
> > > this information to pass on the speed grade information to
> > > the SoC code.
> > > ---
> > >
> > > Should the system_rev somehow reflect that revision? Any way I can check it?
> >
> > Can you check if the procedure in doc/README.davinci in U-Boot sources
> > still works?
> >
> > Environment Variables
> > =====================
> >
> > The DA850 EVM allows the user to specify the maximum cpu clock allowed by the
> > silicon, in Hz, via an environment variable "maxcpuclk".
> >
> > The maximum clock rate allowed depends on the silicon populated on the EVM.
> > Please make sure you understand the restrictions placed on this clock in the
> > device specific datasheet before setting up this variable. This information is
> > passed to the Linux kernel using the ATAG_REVISION atag.
> >
> > If "maxcpuclk" is not defined, the configuration CONFIG_DA850_EVM_MAX_CPU_CLK
> > is used to obtain this information.
> >
> > Thanks,
> > Sekhar
>
> Hi Sekhar,
>
> I built the current upstream u-boot and the get_board_rev() function
> for da850-evm doesn't seem to be called at all. For instance the
> lego-ev3 platform does this:
>
> ./lego/ev3/legoev3.c:108: board_rev = get_board_rev();
>
> but in davinci this function seems to be unused and I don't see it
> called from any other core u-boot component. I don't see any commit
> that would mention this function but there are a lot of commits
> removing get_board_rev() for other boards in git log. Is it possible
> it stopped being used at some point?

Look for setup_revision_tag in arch/arm/lib/bootm.c

The function appears to be called from there.

There is a __weak reference in the header file which I think allows
people to remove them without breaking bootm.

adam
>
> Bart

Re: [PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm

[Bartosz Golaszewski]

śr., 3 kwi 2019 o 17:49 Adam Ford <aford173@gmail.com> napisał(a):
>
> On Wed, Apr 3, 2019 at 7:50 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> >
> > śr., 27 mar 2019 o 12:14 Sekhar Nori <nsekhar@ti.com> napisał(a):
> > >
> > > Hi Bart,
> > >
> > > On 26/03/19 11:21 PM, Bartosz Golaszewski wrote:
> > > > wt., 26 mar 2019 o 15:00 Adam Ford <aford173@gmail.com> napisał(a):
> > > >>
> > > >> On Fri, Mar 22, 2019 at 8:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> > > >>>
> > > >>> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > > >>>
> > > >>> The system_rev variable is never set on davinci and is always 0, so
> > > >>> we're using the default max operating point of 300MHz. The cvdd supply
> > > >>> comes from the tps6507 pmic and the voltage can go all the way to 1.3V
> > > >>> so the maximum supported rate should be 456MHz.
> > > >>
> > > >> My understanding is that only certain revisions of the silicon can go
> > > >> to 456MHz.   The L138's Datasheet lists both a 456 and 375 version.  I
> > > >> cannot find a way to read a register to determine which version of the
> > > >> silicon is available. Maybe Sekhar can confirm.
> > > >>
> > > >
> > > > Commit 28bd2c341120 ("davinci: am18x/da850/omap-l138 evm: add support
> > > > for higher speed grades") mentions the following:
> > > >
> > > > ---
> > > > U-Boot on the EVM sets up ATAG_REVISION to inform the OS
> > > > regarding the speed grade supported by the silicon. We use
> > > > this information to pass on the speed grade information to
> > > > the SoC code.
> > > > ---
> > > >
> > > > Should the system_rev somehow reflect that revision? Any way I can check it?
> > >
> > > Can you check if the procedure in doc/README.davinci in U-Boot sources
> > > still works?
> > >
> > > Environment Variables
> > > =====================
> > >
> > > The DA850 EVM allows the user to specify the maximum cpu clock allowed by the
> > > silicon, in Hz, via an environment variable "maxcpuclk".
> > >
> > > The maximum clock rate allowed depends on the silicon populated on the EVM.
> > > Please make sure you understand the restrictions placed on this clock in the
> > > device specific datasheet before setting up this variable. This information is
> > > passed to the Linux kernel using the ATAG_REVISION atag.
> > >
> > > If "maxcpuclk" is not defined, the configuration CONFIG_DA850_EVM_MAX_CPU_CLK
> > > is used to obtain this information.
> > >
> > > Thanks,
> > > Sekhar
> >
> > Hi Sekhar,
> >
> > I built the current upstream u-boot and the get_board_rev() function
> > for da850-evm doesn't seem to be called at all. For instance the
> > lego-ev3 platform does this:
> >
> > ./lego/ev3/legoev3.c:108: board_rev = get_board_rev();
> >
> > but in davinci this function seems to be unused and I don't see it
> > called from any other core u-boot component. I don't see any commit
> > that would mention this function but there are a lot of commits
> > removing get_board_rev() for other boards in git log. Is it possible
> > it stopped being used at some point?
>
> Look for setup_revision_tag in arch/arm/lib/bootm.c
>
> The function appears to be called from there.
>
> There is a __weak reference in the header file which I think allows
> people to remove them without breaking bootm.
>
> adam
> >
> > Bart

Thanks, now verified that this still works in board file mode for
da850-evm. Now the questions is - what about DT mode? Should we only
enable the lowest possible mode (300MHz) and leave it to the user to
enable any higher frequencies?

Bart

Re: [PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm

[Adam Ford]

On Thu, Apr 4, 2019 at 5:01 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> śr., 3 kwi 2019 o 17:49 Adam Ford <aford173@gmail.com> napisał(a):
> >
> > On Wed, Apr 3, 2019 at 7:50 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> > >
> > > śr., 27 mar 2019 o 12:14 Sekhar Nori <nsekhar@ti.com> napisał(a):
> > > >
> > > > Hi Bart,
> > > >
> > > > On 26/03/19 11:21 PM, Bartosz Golaszewski wrote:
> > > > > wt., 26 mar 2019 o 15:00 Adam Ford <aford173@gmail.com> napisał(a):
> > > > >>
> > > > >> On Fri, Mar 22, 2019 at 8:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> > > > >>>
> > > > >>> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > > > >>>
> > > > >>> The system_rev variable is never set on davinci and is always 0, so
> > > > >>> we're using the default max operating point of 300MHz. The cvdd supply
> > > > >>> comes from the tps6507 pmic and the voltage can go all the way to 1.3V
> > > > >>> so the maximum supported rate should be 456MHz.
> > > > >>
> > > > >> My understanding is that only certain revisions of the silicon can go
> > > > >> to 456MHz.   The L138's Datasheet lists both a 456 and 375 version.  I
> > > > >> cannot find a way to read a register to determine which version of the
> > > > >> silicon is available. Maybe Sekhar can confirm.
> > > > >>
> > > > >
> > > > > Commit 28bd2c341120 ("davinci: am18x/da850/omap-l138 evm: add support
> > > > > for higher speed grades") mentions the following:
> > > > >
> > > > > ---
> > > > > U-Boot on the EVM sets up ATAG_REVISION to inform the OS
> > > > > regarding the speed grade supported by the silicon. We use
> > > > > this information to pass on the speed grade information to
> > > > > the SoC code.
> > > > > ---
> > > > >
> > > > > Should the system_rev somehow reflect that revision? Any way I can check it?
> > > >
> > > > Can you check if the procedure in doc/README.davinci in U-Boot sources
> > > > still works?
> > > >
> > > > Environment Variables
> > > > =====================
> > > >
> > > > The DA850 EVM allows the user to specify the maximum cpu clock allowed by the
> > > > silicon, in Hz, via an environment variable "maxcpuclk".
> > > >
> > > > The maximum clock rate allowed depends on the silicon populated on the EVM.
> > > > Please make sure you understand the restrictions placed on this clock in the
> > > > device specific datasheet before setting up this variable. This information is
> > > > passed to the Linux kernel using the ATAG_REVISION atag.
> > > >
> > > > If "maxcpuclk" is not defined, the configuration CONFIG_DA850_EVM_MAX_CPU_CLK
> > > > is used to obtain this information.
> > > >
> > > > Thanks,
> > > > Sekhar
> > >
> > > Hi Sekhar,
> > >
> > > I built the current upstream u-boot and the get_board_rev() function
> > > for da850-evm doesn't seem to be called at all. For instance the
> > > lego-ev3 platform does this:
> > >
> > > ./lego/ev3/legoev3.c:108: board_rev = get_board_rev();
> > >
> > > but in davinci this function seems to be unused and I don't see it
> > > called from any other core u-boot component. I don't see any commit
> > > that would mention this function but there are a lot of commits
> > > removing get_board_rev() for other boards in git log. Is it possible
> > > it stopped being used at some point?
> >
> > Look for setup_revision_tag in arch/arm/lib/bootm.c
> >
> > The function appears to be called from there.
> >
> > There is a __weak reference in the header file which I think allows
> > people to remove them without breaking bootm.
> >
> > adam
> > >
> > > Bart
>
> Thanks, now verified that this still works in board file mode for
> da850-evm. Now the questions is - what about DT mode? Should we only
> enable the lowest possible mode (300MHz) and leave it to the user to
> enable any higher frequencies?

From everything that I can find in Logic PD's database, the standard
da850-evm kits and SOM's are 375MHz, so I think it's safe to run up to
that speed.  I would disable the speed options for 408 and 456, but
leave them shown for anyone who may have purchased a custom version
with the 456MHz variant which I can also see there are some.  At least
for the L138 and AM1808 SOM's, those customers who who they are, so
making it obvious how to enable it would be a good thing.

Just my two cents.

adam
>
> Bart

Re: [PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm

[Sekhar Nori]

On 04/04/19 4:44 PM, Adam Ford wrote:
> On Thu, Apr 4, 2019 at 5:01 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>>
>> śr., 3 kwi 2019 o 17:49 Adam Ford <aford173@gmail.com> napisał(a):
>>>
>>> On Wed, Apr 3, 2019 at 7:50 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>>>>
>>>> śr., 27 mar 2019 o 12:14 Sekhar Nori <nsekhar@ti.com> napisał(a):
>>>>>
>>>>> Hi Bart,
>>>>>
>>>>> On 26/03/19 11:21 PM, Bartosz Golaszewski wrote:
>>>>>> wt., 26 mar 2019 o 15:00 Adam Ford <aford173@gmail.com> napisał(a):
>>>>>>>
>>>>>>> On Fri, Mar 22, 2019 at 8:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>>>>>>>>
>>>>>>>> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>>>>>>>>
>>>>>>>> The system_rev variable is never set on davinci and is always 0, so
>>>>>>>> we're using the default max operating point of 300MHz. The cvdd supply
>>>>>>>> comes from the tps6507 pmic and the voltage can go all the way to 1.3V
>>>>>>>> so the maximum supported rate should be 456MHz.
>>>>>>>
>>>>>>> My understanding is that only certain revisions of the silicon can go
>>>>>>> to 456MHz.   The L138's Datasheet lists both a 456 and 375 version.  I
>>>>>>> cannot find a way to read a register to determine which version of the
>>>>>>> silicon is available. Maybe Sekhar can confirm.
>>>>>>>
>>>>>>
>>>>>> Commit 28bd2c341120 ("davinci: am18x/da850/omap-l138 evm: add support
>>>>>> for higher speed grades") mentions the following:
>>>>>>
>>>>>> ---
>>>>>> U-Boot on the EVM sets up ATAG_REVISION to inform the OS
>>>>>> regarding the speed grade supported by the silicon. We use
>>>>>> this information to pass on the speed grade information to
>>>>>> the SoC code.
>>>>>> ---
>>>>>>
>>>>>> Should the system_rev somehow reflect that revision? Any way I can check it?
>>>>>
>>>>> Can you check if the procedure in doc/README.davinci in U-Boot sources
>>>>> still works?
>>>>>
>>>>> Environment Variables
>>>>> =====================
>>>>>
>>>>> The DA850 EVM allows the user to specify the maximum cpu clock allowed by the
>>>>> silicon, in Hz, via an environment variable "maxcpuclk".
>>>>>
>>>>> The maximum clock rate allowed depends on the silicon populated on the EVM.
>>>>> Please make sure you understand the restrictions placed on this clock in the
>>>>> device specific datasheet before setting up this variable. This information is
>>>>> passed to the Linux kernel using the ATAG_REVISION atag.
>>>>>
>>>>> If "maxcpuclk" is not defined, the configuration CONFIG_DA850_EVM_MAX_CPU_CLK
>>>>> is used to obtain this information.
>>>>>
>>>>> Thanks,
>>>>> Sekhar
>>>>
>>>> Hi Sekhar,
>>>>
>>>> I built the current upstream u-boot and the get_board_rev() function
>>>> for da850-evm doesn't seem to be called at all. For instance the
>>>> lego-ev3 platform does this:
>>>>
>>>> ./lego/ev3/legoev3.c:108: board_rev = get_board_rev();
>>>>
>>>> but in davinci this function seems to be unused and I don't see it
>>>> called from any other core u-boot component. I don't see any commit
>>>> that would mention this function but there are a lot of commits
>>>> removing get_board_rev() for other boards in git log. Is it possible
>>>> it stopped being used at some point?
>>>
>>> Look for setup_revision_tag in arch/arm/lib/bootm.c
>>>
>>> The function appears to be called from there.
>>>
>>> There is a __weak reference in the header file which I think allows
>>> people to remove them without breaking bootm.
>>>
>>> adam
>>>>
>>>> Bart
>>
>> Thanks, now verified that this still works in board file mode for
>> da850-evm. Now the questions is - what about DT mode? Should we only
>> enable the lowest possible mode (300MHz) and leave it to the user to
>> enable any higher frequencies?
> 
> From everything that I can find in Logic PD's database, the standard
> da850-evm kits and SOM's are 375MHz, so I think it's safe to run up to
> that speed.  I would disable the speed options for 408 and 456, but
> leave them shown for anyone who may have purchased a custom version
> with the 456MHz variant which I can also see there are some.  At least
> for the L138 and AM1808 SOM's, those customers who who they are, so
> making it obvious how to enable it would be a good thing.
> 
> Just my two cents.

Sounds good to me.

Thanks,
Sekhar