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Sam Protsenko authored
Implement support for CPU clock management units: - CMU_CPUCL0: clocks for cluster 0: 4 x Cortex-A55 (cpu0..cpu3) - CMU_CPUCL1: clocks for cluster 1: 4 x Cortex-A55 (cpu4..cpu7) CPU PLLs are generating main CPU clocks for each cluster, and there are alternate ("switch") clocks that can be used temporarily while re-configuring the PLL for a new rate. ACLK, ATCLK, PCLKDBG and PERIPHCLK clocks are driving corresponding buses. CLK_CLUSTERx_SCLK are actual leaf CPU clocks and should be used to change CPU rates. Also some CoreSight clocks can be derived from DBG_USER (debug clock). PLL table was extracted from ECT table. ECT stands for "Exynos Characteristic Table", it's a Samsung specific binary data populated by BL2 bootloader in RAM at 0x90000000 address, containing PLL tables for various CMUs and other hardware specific information. The particular PLL type used in CMU_CPUCL0 and CMU_CPUCL1 (pll0822x) is an integer PLL with middle FVCO. The equation to calculate its output rate is: fout = fin * M / (P*2^S) where: fin = 26 MHz (OSCCLK frequency) M = 64..1023 P = 1..63 S = 0..6 The PLL table tries to keep "P" value low to reduce the locking time, which for pll0822x is "t = P * 150" (in OSCCLK cycles). Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org> Link: https://lore.kernel.org/r/20240301015118.30072-2-semen.protsenko@linaro.orgSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
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