Hi Baruch, 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. Reviewed-by: Chris Packham <judge.pack...@gmail.com> Tested-by: Chris Packham <judge.pack...@gmail.com> > --- > 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. > -- > 2.20.1 > > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > https://lists.denx.de/listinfo/u-boot _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot