On Tue, Jun 25, 2019 at 5:50 PM Baruch Siach <bar...@tkos.co.il> wrote: > > Hi Chris, > > On Tue, Jun 25 2019, Chris Packham wrote: > > On Mon, Jun 24, 2019 at 8:30 PM Baruch Siach <bar...@tkos.co.il> wrote: > >> > >> Reduce Auto Voltage Scaling VDD limit when core frequency is lower than > >> 1600MHz. This reduces core voltage level from 1.25V to 1.15V, which > >> saves power. > >> > >> The code is taken from Marvell's U-Boot 2013.01 revision 18.06. > >> > >> Signed-off-by: Baruch Siach <bar...@tkos.co.il> > > > > I gave it a quick spin on DB-88F6820-AMC and x530. Both booted fine. > > Is there AVS feedback circuit on these boards? If so, have you measured > how this patch affects core voltage? >
Both boards have circuitry for AVS_FB although the x530 strapping will probably mean that this code skips it. I'll see if I can measure and difference in behaviour tomorrow. > > Reviewed-by: Chris Packham <judge.pack...@gmail.com> > > Tested-by: Chris Packham <judge.pack...@gmail.com> > > Thanks, > baruch > > >> --- > >> arch/arm/mach-mvebu/include/mach/cpu.h | 3 +++ > >> arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.c | 26 +++++++++++++++++++ > >> arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h | 4 +++ > >> arch/arm/mach-mvebu/spl.c | 3 +++ > >> 4 files changed, 36 insertions(+) > >> > >> diff --git a/arch/arm/mach-mvebu/include/mach/cpu.h > >> b/arch/arm/mach-mvebu/include/mach/cpu.h > >> index e6140d67293e..e1128ee90f01 100644 > >> --- a/arch/arm/mach-mvebu/include/mach/cpu.h > >> +++ b/arch/arm/mach-mvebu/include/mach/cpu.h > >> @@ -163,6 +163,9 @@ int serdes_phy_config(void); > >> */ > >> int ddr3_init(void); > >> > >> +/* Auto Voltage Scaling */ > >> +void mv_avs_init(void); > >> + > >> /* > >> * get_ref_clk > >> * > >> diff --git a/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.c > >> b/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.c > >> index d387893af37d..e9dd096ad0f5 100644 > >> --- a/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.c > >> +++ b/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.c > >> @@ -256,3 +256,29 @@ u8 sys_env_device_rev_get(void) > >> value = reg_read(DEV_VERSION_ID_REG); > >> return (value & (REVISON_ID_MASK)) >> REVISON_ID_OFFS; > >> } > >> + > >> +void mv_avs_init(void) > >> +{ > >> + u32 sar_freq; > >> + > >> + if (!(IS_ENABLED(CONFIG_ARMADA_38X) || > >> IS_ENABLED(CONFIG_ARMADA_39X))) > >> + return; > >> + > >> + reg_write(AVS_DEBUG_CNTR_REG, AVS_DEBUG_CNTR_DEFAULT_VALUE); > >> + reg_write(AVS_DEBUG_CNTR_REG, AVS_DEBUG_CNTR_DEFAULT_VALUE); > >> + > >> + sar_freq = reg_read(DEVICE_SAMPLE_AT_RESET1_REG); > >> + sar_freq = sar_freq >> SAR_FREQ_OFFSET & SAR_FREQ_MASK; > >> + > >> + /* Set AVS value only for core frequency of 1600MHz or less. > >> + * For higher frequency leave the default value. > >> + */ > >> + if (sar_freq <= 0xd) { > >> + u32 avs_reg_data = reg_read(AVS_ENABLED_CONTROL); > >> + > >> + avs_reg_data &= ~(AVS_LOW_VDD_LIMIT_MASK > >> + | AVS_HIGH_VDD_LIMIT_MASK); > >> + avs_reg_data |= AVS_LOW_VDD_SLOW_VAL | > >> AVS_HIGH_VDD_SLOW_VAL; > >> + reg_write(AVS_ENABLED_CONTROL, avs_reg_data); > >> + } > >> +} > >> diff --git a/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h > >> b/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h > >> index 365332d2b048..1774a5b780ca 100644 > >> --- a/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h > >> +++ b/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h > >> @@ -33,6 +33,8 @@ > >> #define DEV_ID_REG_DEVICE_ID_OFFS 16 > >> #define DEV_ID_REG_DEVICE_ID_MASK 0xffff0000 > >> > >> +#define SAR_FREQ_OFFSET 10 > >> +#define SAR_FREQ_MASK 0x1f > >> #define SAR_DEV_ID_OFFS 27 > >> #define SAR_DEV_ID_MASK 0x7 > >> > >> @@ -155,10 +157,12 @@ > >> #define AVS_LOW_VDD_LIMIT_OFFS 4 > >> #define AVS_LOW_VDD_LIMIT_MASK (0xff << AVS_LOW_VDD_LIMIT_OFFS) > >> #define AVS_LOW_VDD_LIMIT_VAL (0x27 << AVS_LOW_VDD_LIMIT_OFFS) > >> +#define AVS_LOW_VDD_SLOW_VAL (0x23 << AVS_LOW_VDD_LIMIT_OFFS) > >> > >> #define AVS_HIGH_VDD_LIMIT_OFFS 12 > >> #define AVS_HIGH_VDD_LIMIT_MASK (0xff << > >> AVS_HIGH_VDD_LIMIT_OFFS) > >> #define AVS_HIGH_VDD_LIMIT_VAL (0x27 << AVS_HIGH_VDD_LIMIT_OFFS) > >> +#define AVS_HIGH_VDD_SLOW_VAL (0x23 << AVS_HIGH_VDD_LIMIT_OFFS) > >> > >> /* Board ID numbers */ > >> #define MARVELL_BOARD_ID_MASK 0x10 > >> diff --git a/arch/arm/mach-mvebu/spl.c b/arch/arm/mach-mvebu/spl.c > >> index d54de5195624..3cb27b7f4b20 100644 > >> --- a/arch/arm/mach-mvebu/spl.c > >> +++ b/arch/arm/mach-mvebu/spl.c > >> @@ -126,6 +126,9 @@ void board_init_f(ulong dummy) > >> ddr3_init(); > >> #endif > >> > >> + /* Initialize Auto Voltage Scaling */ > >> + mv_avs_init(); > >> + > >> /* > >> * Return to the BootROM to continue the Marvell xmodem > >> * UART boot protocol. As initiated by the kwboot tool. > > -- > http://baruch.siach.name/blog/ ~. .~ Tk Open Systems > =}------------------------------------------------ooO--U--Ooo------------{= > - bar...@tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il - _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot