From: k.kozlowski@samsung•com (Krzysztof Kozlowski)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v5 3/7] ARM: dts: Exynos542x/5800: add CPU OPP properties
Date: Fri, 11 Dec 2015 13:53:26 +0900 [thread overview]
Message-ID: <566A56C6.2000503@samsung.com> (raw)
In-Reply-To: <20151211043802.GP3612@ubuntu>
On 11.12.2015 13:38, Viresh Kumar wrote:
> On 11-12-15, 13:18, Krzysztof Kozlowski wrote:
>> We had such configuration before (before df09df6f9ac3). I don't see any
>> benefit in what you described. Where is the "thing" to be fixed? It is
>> mixed up. The contiguous ordering is easier to read and more natural.
>
> This is what you are doing today (keeping on one CPU per cluster to
> simplify it):
>
> cpu0: cpu at 0 {
> device_type = "cpu";
> compatible = "arm,cortex-a15";
> reg = <0x0>;
> clock-frequency = <1800000000>;
> cci-control-port = <&cci_control1>;
> };
>
> cpu4: cpu at 100 {
> device_type = "cpu";
> compatible = "arm,cortex-a7";
> reg = <0x100>;
> clock-frequency = <1000000000>;
> cci-control-port = <&cci_control0>;
> };
>
>
> Then you overwrite it with:
>
> &cpu0 {
> device_type = "cpu";
> compatible = "arm,cortex-a7";
> reg = <0x100>;
> clock-frequency = <1000000000>;
> cci-control-port = <&cci_control0>;
> };
>
> &cpu4 {
> device_type = "cpu";
> compatible = "arm,cortex-a15";
> reg = <0x0>;
> clock-frequency = <1800000000>;
> cci-control-port = <&cci_control1>;
> };
>
>
> Don't you think this isn't the right way of solving problems?
>
> The DT overwrite feature isn't there to do such kind of stuff, though
> it doesn't stop you from doing that.
This is quite ugly, indeed, and it is getting uglier :)... but it does
not violate the idea of DT to describe the hardware. Both hardware
descriptions - the 5420 and overridden - are entirely correct... because
the CPU ordering comes from booting sequence (actually code in IROM
decides according to pulled up GPIO gpg2-1).
> Either you should keep separate paths for both the SoCs,
I like that idea. That makes it much more readable. Thanks for feedback!
I will send a patch for that.
> or can solve
> it the way I suggested earlier.
>
> This came up because in the current series you are doing this:
>
> cpu0: cpu at 0 {
> compatible = "arm,cortex-a15";
> operating-points-v2 = <&cpu0_opp_table>;
> };
>
> cpu4: cpu at 100 {
> device_type = "cpu";
> compatible = "arm,cortex-a7";
> operating-points-v2 = <&cpu1_opp_table>;
> };
>
>
> Then you overwrite it with:
>
> &cpu0 {
> compatible = "arm,cortex-a7";
> operating-points-v2 = <&cpu1_opp_table>;
> };
>
> &cpu4 {
> compatible = "arm,cortex-a15";
> operating-points-v2 = <&cpu0_opp_table>;
> };
Yes, it is getting uglier with each change...
Best regards,
Krzysztof
next prev parent reply other threads:[~2015-12-11 4:53 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-10 16:58 [PATCH v5 0/7] cpufreq: add generic cpufreq driver support for Exynos542x/5800 platforms Bartlomiej Zolnierkiewicz
2015-12-10 16:58 ` [PATCH v5 1/7] ARM: dts: Exynos542x/5800: add cluster regulator supply properties Bartlomiej Zolnierkiewicz
2015-12-11 1:16 ` Krzysztof Kozlowski
2015-12-10 16:58 ` [PATCH v5 2/7] clk: samsung: exynos5420: add cpu clock configuration data and instantiate cpu clock Bartlomiej Zolnierkiewicz
2015-12-10 16:58 ` [PATCH v5 3/7] ARM: dts: Exynos542x/5800: add CPU OPP properties Bartlomiej Zolnierkiewicz
2015-12-11 1:17 ` Krzysztof Kozlowski
2015-12-11 3:16 ` Viresh Kumar
2015-12-11 3:25 ` Javier Martinez Canillas
2015-12-11 3:32 ` Viresh Kumar
2015-12-11 4:00 ` Krzysztof Kozlowski
2015-12-11 4:13 ` Viresh Kumar
2015-12-11 4:18 ` Krzysztof Kozlowski
2015-12-11 4:38 ` Viresh Kumar
2015-12-11 4:53 ` Krzysztof Kozlowski [this message]
2015-12-11 4:53 ` Javier Martinez Canillas
2015-12-11 5:28 ` Krzysztof Kozlowski
2015-12-11 5:41 ` Viresh Kumar
2015-12-11 4:39 ` Viresh Kumar
2015-12-10 16:58 ` [PATCH v5 4/7] ARM: Exynos: use generic cpufreq driver for Exynos5420 Bartlomiej Zolnierkiewicz
2015-12-11 1:18 ` Krzysztof Kozlowski
2015-12-10 16:58 ` [PATCH v5 5/7] clk: samsung: exynos5422/5800: fix cpu clock configuration data Bartlomiej Zolnierkiewicz
2015-12-10 16:58 ` [PATCH v5 6/7] ARM: dts: Exynos5800: fix CPU OPP Bartlomiej Zolnierkiewicz
2015-12-11 1:27 ` Krzysztof Kozlowski
2015-12-10 16:58 ` [PATCH v5 7/7] ARM: Exynos: use generic cpufreq driver for Exynos5422/5800 Bartlomiej Zolnierkiewicz
2015-12-11 1:27 ` Krzysztof Kozlowski
2015-12-11 1:34 ` [PATCH v5 0/7] cpufreq: add generic cpufreq driver support for Exynos542x/5800 platforms Krzysztof Kozlowski
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