Hello, On 08/03/2017 04:03 AM, Shawn Guo wrote: > On Fri, Jul 28, 2017 at 10:36:33AM +0200, Sébastien Szymanski wrote: >> Setting the frequency higher than 528Mhz actually sets the ARM >> clock to 528MHz. That's because PLL2 is used as the root clock when the >> frequency is higher than 396MHz. >> >> cpupower frequency-set -f 792000 >> >> arm_clk_root on the CCM_CLKO2 signal is 528MHz instead of 792MHz. >> >> [ 61.606383] cpu cpu0: 396 MHz, 1025 mV --> 792 MHz, 1225 mV >> >> pll2 1 1 528000000 0 0 >> pll2_bypass 1 1 528000000 0 0 >> pll2_bus 3 3 528000000 0 0 >> ca7_secondary_sel 1 1 528000000 0 0 >> step 1 1 528000000 0 0 >> pll1_sw 1 1 528000000 0 0 >> arm 1 1 528000000 0 0 >> >> Fixes this by using the PLL1 as the root clock when the frequency is >> higher than 528MHz. >> >> cpupower frequency-set -f 792000 >> >> arm_clk_root on the CCM_CLKO2 signal is now 792MHz as expected. >> >> [ 69.717987] cpu cpu0: 198 MHz, 950 mV --> 792 MHz, 1225 mV >> >> pll1 1 1 792000000 0 0 >> pll1_bypass 1 1 792000000 0 0 >> pll1_sys 1 1 792000000 0 0 >> pll1_sw 1 1 792000000 0 0 >> arm 1 1 792000000 0 0 >> >> Signed-off-by: Sébastien Szymanski <sebastien.szyman...@armadeus.com> > > Can you please specify on which SoCs you are seeing this problem? And I > would like invite Anson and Leonard to review it.
My SoC is MCIMX6Y2CVM08AA which is a 792MHz i.MX6ULL. I forgot to mention that I added the following operating points in my device tree: operating-points: 792000 1225000 fsl,soc-operating-points: 792000 1175000 Best regards, > > Shawn > >> --- >> drivers/cpufreq/imx6q-cpufreq.c | 11 +++++++++-- >> 1 file changed, 9 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/cpufreq/imx6q-cpufreq.c >> b/drivers/cpufreq/imx6q-cpufreq.c >> index b6edd3c..e5fba50 100644 >> --- a/drivers/cpufreq/imx6q-cpufreq.c >> +++ b/drivers/cpufreq/imx6q-cpufreq.c >> @@ -18,6 +18,7 @@ >> >> #define PU_SOC_VOLTAGE_NORMAL 1250000 >> #define PU_SOC_VOLTAGE_HIGH 1275000 >> +#define FREQ_528_MHZ 528000000 >> #define FREQ_1P2_GHZ 1200000000 >> >> static struct regulator *arm_reg; >> @@ -110,14 +111,20 @@ static int imx6q_set_target(struct cpufreq_policy >> *policy, unsigned int index) >> * voltage of 528MHz, so lower the CPU frequency to one >> * half before changing CPU frequency. >> */ >> - clk_set_rate(arm_clk, (old_freq >> 1) * 1000); >> - clk_set_parent(pll1_sw_clk, pll1_sys_clk); >> + if ((old_freq * 1000) <= FREQ_528_MHZ) { >> + clk_set_rate(arm_clk, (old_freq >> 1) * 1000); >> + clk_set_parent(pll1_sw_clk, pll1_sys_clk); >> + } >> if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) >> clk_set_parent(secondary_sel_clk, pll2_bus_clk); >> else >> clk_set_parent(secondary_sel_clk, pll2_pfd2_396m_clk); >> clk_set_parent(step_clk, secondary_sel_clk); >> clk_set_parent(pll1_sw_clk, step_clk); >> + if (freq_hz > FREQ_528_MHZ) { >> + clk_set_rate(pll1_sys_clk, freq_hz); >> + clk_set_parent(pll1_sw_clk, pll1_sys_clk); >> + } >> } else { >> clk_set_parent(step_clk, pll2_pfd2_396m_clk); >> clk_set_parent(pll1_sw_clk, step_clk); >> -- >> 2.7.3 >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-ker...@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- Sébastien Szymanski Software engineer, Armadeus Systems Tel: +33 (0)9 72 29 41 44 Fax: +33 (0)9 72 28 79 26