The differences in the vendor-approved CPU and GPU OPPs for the standard Rockchip RK3588 variant [1] and the industrial Rockchip RK3588J variant [2] come from the latter, presumably, supporting an extended temperature range that's usually associated with industrial applications, despite the two SoC variant datasheets specifying the same upper limit for the allowed ambient temperature for both variants. However, the lower temperature limit is specified much lower for the RK3588J variant. [1][2]
To be on the safe side and to ensure maximum longevity of the RK3588J SoCs, only the CPU and GPU OPPs that are declared by the vendor to be always safe for this SoC variant may be provided. As explained by the vendor [3] and according to the RK3588J datasheet, [2] higher-frequency/higher-voltage CPU and GPU OPPs can be used as well, but at the risk of reducing the SoC lifetime expectancy. Presumably, using the higher OPPs may be safe only when not enjoying the assumed extended temperature range that the RK3588J, as an SoC variant targeted specifically at higher-temperature, industrial applications, is made (or binned) for.
Anyone able to keep their RK3588J-based board outside the above-presumed extended temperature range at all times, and willing to take the associated risk of possibly reducing the SoC lifetime expectancy, is free to apply a DT overlay that adds the higher CPU and GPU OPPs.
With all this and the downstream RK3588(J) DT definitions [4][5] in mind, let's delete the RK3588J CPU and GPU OPPs that are not considered belonging to the normal operation mode for this SoC variant. To quote the RK3588J datasheet [2], "normal mode means the chipset works under safety voltage and frequency; for the industrial environment, highly recommend to keep in normal mode, the lifetime is reasonably guaranteed", while "overdrive mode brings higher frequency, and the voltage will increase accordingly; under the overdrive mode for a long time, the chipset may shorten the lifetime, especially in high-temperature condition".
To sum the RK3588J datasheet [2] and the vendor-provided DTs up, [4][5] the maximum allowed CPU core, GPU and NPU frequencies are as follows:
IP core | Normal mode | Overdrive mode ------------+-------------+---------------- Cortex-A55 | 1,296 MHz | 1,704 MHz Cortex-A76 | 1,608 MHz | 2,016 MHz GPU | 700 MHz | 850 MHz NPU | 800 MHz | 950 MHz
Unfortunately, when it comes to the actual voltages for the RK3588J CPU and GPU OPPs, there's a discrepancy between the RK3588J datasheet [2] and the downstream kernel code. [4][5] The RK3588J datasheet states that "the max. working voltage of CPU/GPU/NPU is 0.75 V under the normal mode", while the downstream kernel code actually allows voltage ranges that go up to 0.95 V, which is still within the voltage range allowed by the datasheet. However, the RK3588J datasheet also tells us to "strictly refer to the software configuration of SDK and the hardware reference design", so let's embrace the voltage ranges provided by the downstream kernel code, which also prevents the undesirable theoretical outcome of ending up with no usable OPPs on a particular board, as a result of the board's voltage regulator(s) being unable to deliver the exact voltages, for whatever reason.
The above-described voltage ranges for the RK3588J CPU OPPs remain taken from the downstream kernel code [4][5] by picking the highest, worst-bin values, which ensure that all RK3588J bins will work reliably. Yes, with some power inevitably wasted as unnecessarily generated heat, but the reliability is paramount, together with the longevity. This deficiency may be revisited separately at some point in the future.
The provided RK3588J CPU OPPs follow the slightly debatable "provide only the highest-frequency OPP from the same-voltage group" approach that's been established earlier, [6] as a result of the "same-voltage, lower-frequency" OPPs being considered inefficient from the IPA governor's standpoint, which may also be revisited separately at some point in the future.
[1] https://wiki.friendlyelec.com/wiki/images/e/ee/Rockchip_RK3588_Datasheet_V1.... [2] https://wmsc.lcsc.com/wmsc/upload/file/pdf/v2/lcsc/2403201054_Rockchip-RK358... [3] https://lore.kernel.org/linux-rockchip/e55125ed-64fb-455e-b1e4-cebe2cf006e4@... [4] https://raw.githubusercontent.com/rockchip-linux/kernel/604cec4004abe5a96c73... [5] https://raw.githubusercontent.com/rockchip-linux/kernel/604cec4004abe5a96c73... [6] https://lore.kernel.org/all/20240229-rk-dts-additions-v3-5-6afe8473a631@gmai...
Fixes: 667885a68658 ("arm64: dts: rockchip: Add OPP data for CPU cores on RK3588j") Fixes: a7b2070505a2 ("arm64: dts: rockchip: Split GPU OPPs of RK3588 and RK3588j") Cc: stable@vger.kernel.org Cc: Heiko Stuebner heiko@sntech.de Cc: Alexey Charkov alchark@gmail.com Helped-by: Quentin Schulz quentin.schulz@cherry.de Reviewed-by: Quentin Schulz quentin.schulz@cherry.de Signed-off-by: Dragan Simic dsimic@manjaro.org ---
Notes: Changes in v2: - Reworded and expanded the patch description a bit, to include some more information and to make it more clear what are the implied speculations and assumptions, and what are the available official statements from Rockchip, as suggested by Quentin [7] - Collected Reviewed-by tag from Quentin [7]
Link to v1: https://lore.kernel.org/linux-rockchip/f929da061de35925ea591c969f985430e23c4...
[7] https://lore.kernel.org/linux-rockchip/71b7c81b-6a4e-442b-a661-04d63639962a@...
arch/arm64/boot/dts/rockchip/rk3588j.dtsi | 53 ++++++++--------------- 1 file changed, 17 insertions(+), 36 deletions(-)
diff --git a/arch/arm64/boot/dts/rockchip/rk3588j.dtsi b/arch/arm64/boot/dts/rockchip/rk3588j.dtsi index bce72bac4503..3045cb3bd68c 100644 --- a/arch/arm64/boot/dts/rockchip/rk3588j.dtsi +++ b/arch/arm64/boot/dts/rockchip/rk3588j.dtsi @@ -11,74 +11,59 @@ cluster0_opp_table: opp-table-cluster0 { compatible = "operating-points-v2"; opp-shared;
- opp-1416000000 { - opp-hz = /bits/ 64 <1416000000>; + opp-1200000000 { + opp-hz = /bits/ 64 <1200000000>; opp-microvolt = <750000 750000 950000>; clock-latency-ns = <40000>; opp-suspend; }; - opp-1608000000 { - opp-hz = /bits/ 64 <1608000000>; - opp-microvolt = <887500 887500 950000>; - clock-latency-ns = <40000>; - }; - opp-1704000000 { - opp-hz = /bits/ 64 <1704000000>; - opp-microvolt = <937500 937500 950000>; + opp-1296000000 { + opp-hz = /bits/ 64 <1296000000>; + opp-microvolt = <775000 775000 950000>; clock-latency-ns = <40000>; }; };
cluster1_opp_table: opp-table-cluster1 { compatible = "operating-points-v2"; opp-shared;
+ opp-1200000000{ + opp-hz = /bits/ 64 <1200000000>; + opp-microvolt = <750000 750000 950000>; + clock-latency-ns = <40000>; + }; opp-1416000000 { opp-hz = /bits/ 64 <1416000000>; - opp-microvolt = <750000 750000 950000>; + opp-microvolt = <762500 762500 950000>; clock-latency-ns = <40000>; }; opp-1608000000 { opp-hz = /bits/ 64 <1608000000>; opp-microvolt = <787500 787500 950000>; clock-latency-ns = <40000>; }; - opp-1800000000 { - opp-hz = /bits/ 64 <1800000000>; - opp-microvolt = <875000 875000 950000>; - clock-latency-ns = <40000>; - }; - opp-2016000000 { - opp-hz = /bits/ 64 <2016000000>; - opp-microvolt = <950000 950000 950000>; - clock-latency-ns = <40000>; - }; };
cluster2_opp_table: opp-table-cluster2 { compatible = "operating-points-v2"; opp-shared;
+ opp-1200000000{ + opp-hz = /bits/ 64 <1200000000>; + opp-microvolt = <750000 750000 950000>; + clock-latency-ns = <40000>; + }; opp-1416000000 { opp-hz = /bits/ 64 <1416000000>; - opp-microvolt = <750000 750000 950000>; + opp-microvolt = <762500 762500 950000>; clock-latency-ns = <40000>; }; opp-1608000000 { opp-hz = /bits/ 64 <1608000000>; opp-microvolt = <787500 787500 950000>; clock-latency-ns = <40000>; }; - opp-1800000000 { - opp-hz = /bits/ 64 <1800000000>; - opp-microvolt = <875000 875000 950000>; - clock-latency-ns = <40000>; - }; - opp-2016000000 { - opp-hz = /bits/ 64 <2016000000>; - opp-microvolt = <950000 950000 950000>; - clock-latency-ns = <40000>; - }; };
gpu_opp_table: opp-table { @@ -104,10 +89,6 @@ opp-700000000 { opp-hz = /bits/ 64 <700000000>; opp-microvolt = <750000 750000 850000>; }; - opp-850000000 { - opp-hz = /bits/ 64 <800000000>; - opp-microvolt = <787500 787500 850000>; - }; }; };