diff mbox

[2/2] clk: sunxi-ng: sun50i: a64: Add 2x fixed post-divider to MMC module clocks

Message ID 20171204051912.7485-3-wens@csie.org (mailing list archive)
State Mainlined, archived
Headers show

Commit Message

Chen-Yu Tsai Dec. 4, 2017, 5:19 a.m. UTC
On the A64, the MMC module clocks are fixed in the new timing mode,
i.e. they do not have a bit to select the mode. These clocks have
a 2x divider somewhere between the clock and the MMC module.

To be consistent with other SoCs supporting the new timing mode,
we model the 2x divider as a fixed post-divider on the MMC module
clocks.

This patch adds the post-dividers to the MMC clocks.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 57 +++++++++++++++++++++++------------
 1 file changed, 37 insertions(+), 20 deletions(-)

Comments

Andre Przywara Dec. 4, 2017, 11:18 p.m. UTC | #1
On 04/12/17 05:19, Chen-Yu Tsai wrote:
> On the A64, the MMC module clocks are fixed in the new timing mode,
> i.e. they do not have a bit to select the mode. These clocks have
> a 2x divider somewhere between the clock and the MMC module.
> 
> To be consistent with other SoCs supporting the new timing mode,
> we model the 2x divider as a fixed post-divider on the MMC module
> clocks.
> 
> This patch adds the post-dividers to the MMC clocks.
> 
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>

Reviewed-by: Andre Przywara <andre.przywara@arm.com>

Cheers,
Andre

> ---
>  drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 57 +++++++++++++++++++++++------------
>  1 file changed, 37 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> index 2bb4cabf802f..ee9c12cf3f08 100644
> --- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> +++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> @@ -400,28 +400,45 @@ static SUNXI_CCU_MP_WITH_MUX_GATE(nand_clk, "nand", mod0_default_parents, 0x080,
>  				  BIT(31),	/* gate */
>  				  0);
>  
> +/*
> + * MMC clocks are the new timing mode (see A83T & H3) variety, but without
> + * the mode switch. This means they have a 2x post divider between the clock
> + * and the MMC module. This is not documented in the manual, but is taken
> + * into consideration when setting the mmc module clocks in the BSP kernel.
> + * Without it, MMC performance is degraded.
> + *
> + * We model it here to be consistent with other SoCs supporting this mode.
> + * The alternative would be to add the 2x multiplier when setting the MMC
> + * module clock in the MMC driver, just for the A64.
> + */
>  static const char * const mmc_default_parents[] = { "osc24M", "pll-periph0-2x",
>  						    "pll-periph1-2x" };
> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc0_clk, "mmc0", mmc_default_parents, 0x088,
> -				  0, 4,		/* M */
> -				  16, 2,	/* P */
> -				  24, 2,	/* mux */
> -				  BIT(31),	/* gate */
> -				  0);
> -
> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc1_clk, "mmc1", mmc_default_parents, 0x08c,
> -				  0, 4,		/* M */
> -				  16, 2,	/* P */
> -				  24, 2,	/* mux */
> -				  BIT(31),	/* gate */
> -				  0);
> -
> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mmc_default_parents, 0x090,
> -				  0, 4,		/* M */
> -				  16, 2,	/* P */
> -				  24, 2,	/* mux */
> -				  BIT(31),	/* gate */
> -				  0);
> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc0_clk, "mmc0",
> +					  mmc_default_parents, 0x088,
> +					  0, 4,		/* M */
> +					  16, 2,	/* P */
> +					  24, 2,	/* mux */
> +					  BIT(31),	/* gate */
> +					  2,		/* post-div */
> +					  0);
> +
> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc1_clk, "mmc1",
> +					  mmc_default_parents, 0x08c,
> +					  0, 4,		/* M */
> +					  16, 2,	/* P */
> +					  24, 2,	/* mux */
> +					  BIT(31),	/* gate */
> +					  2,		/* post-div */
> +					  0);
> +
> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc2_clk, "mmc2",
> +					  mmc_default_parents, 0x090,
> +					  0, 4,		/* M */
> +					  16, 2,	/* P */
> +					  24, 2,	/* mux */
> +					  BIT(31),	/* gate */
> +					  2,		/* post-div */
> +					  0);
>  
>  static const char * const ts_parents[] = { "osc24M", "pll-periph0", };
>  static SUNXI_CCU_MP_WITH_MUX_GATE(ts_clk, "ts", ts_parents, 0x098,
>
Maxime Ripard Dec. 5, 2017, 7:59 p.m. UTC | #2
Hi,

On Mon, Dec 04, 2017 at 01:19:12PM +0800, Chen-Yu Tsai wrote:
> On the A64, the MMC module clocks are fixed in the new timing mode,
> i.e. they do not have a bit to select the mode. These clocks have
> a 2x divider somewhere between the clock and the MMC module.
> 
> To be consistent with other SoCs supporting the new timing mode,
> we model the 2x divider as a fixed post-divider on the MMC module
> clocks.
> 
> This patch adds the post-dividers to the MMC clocks.
> 
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>

I had a doubt applying that one... sorry.

> ---
>  drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 57 +++++++++++++++++++++++------------
>  1 file changed, 37 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> index 2bb4cabf802f..ee9c12cf3f08 100644
> --- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> +++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> @@ -400,28 +400,45 @@ static SUNXI_CCU_MP_WITH_MUX_GATE(nand_clk, "nand", mod0_default_parents, 0x080,
>  				  BIT(31),	/* gate */
>  				  0);
>  
> +/*
> + * MMC clocks are the new timing mode (see A83T & H3) variety, but without
> + * the mode switch. This means they have a 2x post divider between the clock
> + * and the MMC module. This is not documented in the manual, but is taken
> + * into consideration when setting the mmc module clocks in the BSP kernel.
> + * Without it, MMC performance is degraded.
> + *
> + * We model it here to be consistent with other SoCs supporting this mode.
> + * The alternative would be to add the 2x multiplier when setting the MMC
> + * module clock in the MMC driver, just for the A64.
> + */
>  static const char * const mmc_default_parents[] = { "osc24M", "pll-periph0-2x",
>  						    "pll-periph1-2x" };
> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc0_clk, "mmc0", mmc_default_parents, 0x088,
> -				  0, 4,		/* M */
> -				  16, 2,	/* P */
> -				  24, 2,	/* mux */
> -				  BIT(31),	/* gate */
> -				  0);
> -
> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc1_clk, "mmc1", mmc_default_parents, 0x08c,
> -				  0, 4,		/* M */
> -				  16, 2,	/* P */
> -				  24, 2,	/* mux */
> -				  BIT(31),	/* gate */
> -				  0);
> -
> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mmc_default_parents, 0x090,
> -				  0, 4,		/* M */
> -				  16, 2,	/* P */
> -				  24, 2,	/* mux */
> -				  BIT(31),	/* gate */
> -				  0);
> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc0_clk, "mmc0",
> +					  mmc_default_parents, 0x088,
> +					  0, 4,		/* M */
> +					  16, 2,	/* P */
> +					  24, 2,	/* mux */
> +					  BIT(31),	/* gate */
> +					  2,		/* post-div */
> +					  0);
> +
> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc1_clk, "mmc1",
> +					  mmc_default_parents, 0x08c,
> +					  0, 4,		/* M */
> +					  16, 2,	/* P */
> +					  24, 2,	/* mux */
> +					  BIT(31),	/* gate */
> +					  2,		/* post-div */
> +					  0);
> +

Are you sure that the divider there for the non-eMMC clocks? Usually,
the new mode is only here for the eMMC, so we would divide the rate by
two in the non-eMMC case.

Maxime
Chen-Yu Tsai Dec. 6, 2017, 2:30 a.m. UTC | #3
On Wed, Dec 6, 2017 at 3:59 AM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> Hi,
>
> On Mon, Dec 04, 2017 at 01:19:12PM +0800, Chen-Yu Tsai wrote:
>> On the A64, the MMC module clocks are fixed in the new timing mode,
>> i.e. they do not have a bit to select the mode. These clocks have
>> a 2x divider somewhere between the clock and the MMC module.
>>
>> To be consistent with other SoCs supporting the new timing mode,
>> we model the 2x divider as a fixed post-divider on the MMC module
>> clocks.
>>
>> This patch adds the post-dividers to the MMC clocks.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>
> I had a doubt applying that one... sorry.
>
>> ---
>>  drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 57 +++++++++++++++++++++++------------
>>  1 file changed, 37 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
>> index 2bb4cabf802f..ee9c12cf3f08 100644
>> --- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
>> +++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
>> @@ -400,28 +400,45 @@ static SUNXI_CCU_MP_WITH_MUX_GATE(nand_clk, "nand", mod0_default_parents, 0x080,
>>                                 BIT(31),      /* gate */
>>                                 0);
>>
>> +/*
>> + * MMC clocks are the new timing mode (see A83T & H3) variety, but without
>> + * the mode switch. This means they have a 2x post divider between the clock
>> + * and the MMC module. This is not documented in the manual, but is taken
>> + * into consideration when setting the mmc module clocks in the BSP kernel.
>> + * Without it, MMC performance is degraded.
>> + *
>> + * We model it here to be consistent with other SoCs supporting this mode.
>> + * The alternative would be to add the 2x multiplier when setting the MMC
>> + * module clock in the MMC driver, just for the A64.
>> + */
>>  static const char * const mmc_default_parents[] = { "osc24M", "pll-periph0-2x",
>>                                                   "pll-periph1-2x" };
>> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc0_clk, "mmc0", mmc_default_parents, 0x088,
>> -                               0, 4,         /* M */
>> -                               16, 2,        /* P */
>> -                               24, 2,        /* mux */
>> -                               BIT(31),      /* gate */
>> -                               0);
>> -
>> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc1_clk, "mmc1", mmc_default_parents, 0x08c,
>> -                               0, 4,         /* M */
>> -                               16, 2,        /* P */
>> -                               24, 2,        /* mux */
>> -                               BIT(31),      /* gate */
>> -                               0);
>> -
>> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mmc_default_parents, 0x090,
>> -                               0, 4,         /* M */
>> -                               16, 2,        /* P */
>> -                               24, 2,        /* mux */
>> -                               BIT(31),      /* gate */
>> -                               0);
>> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc0_clk, "mmc0",
>> +                                       mmc_default_parents, 0x088,
>> +                                       0, 4,         /* M */
>> +                                       16, 2,        /* P */
>> +                                       24, 2,        /* mux */
>> +                                       BIT(31),      /* gate */
>> +                                       2,            /* post-div */
>> +                                       0);
>> +
>> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc1_clk, "mmc1",
>> +                                       mmc_default_parents, 0x08c,
>> +                                       0, 4,         /* M */
>> +                                       16, 2,        /* P */
>> +                                       24, 2,        /* mux */
>> +                                       BIT(31),      /* gate */
>> +                                       2,            /* post-div */
>> +                                       0);
>> +
>
> Are you sure that the divider there for the non-eMMC clocks? Usually,
> the new mode is only here for the eMMC, so we would divide the rate by
> two in the non-eMMC case.

The new mode is there for all MMC controllers. The other two MMC
controllers even have the old/new timing mode switch. In case you
forgot we have ".need_new_timings" set for the A64 compatible.

But to eliminate any doubts or concerns, I've rerun tests for the
micro SD card, instead of the eMMC. And yes the results are the same,
2x improvement (12 MB/s vs 23.7 MB/s).

ChenYu
Maxime Ripard Dec. 6, 2017, 3:56 p.m. UTC | #4
Hi,

On Wed, Dec 06, 2017 at 10:30:26AM +0800, Chen-Yu Tsai wrote:
> On Wed, Dec 6, 2017 at 3:59 AM, Maxime Ripard
> <maxime.ripard@free-electrons.com> wrote:
> > Hi,
> >
> > On Mon, Dec 04, 2017 at 01:19:12PM +0800, Chen-Yu Tsai wrote:
> >> On the A64, the MMC module clocks are fixed in the new timing mode,
> >> i.e. they do not have a bit to select the mode. These clocks have
> >> a 2x divider somewhere between the clock and the MMC module.
> >>
> >> To be consistent with other SoCs supporting the new timing mode,
> >> we model the 2x divider as a fixed post-divider on the MMC module
> >> clocks.
> >>
> >> This patch adds the post-dividers to the MMC clocks.
> >>
> >> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> >
> > I had a doubt applying that one... sorry.
> >
> >> ---
> >>  drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 57 +++++++++++++++++++++++------------
> >>  1 file changed, 37 insertions(+), 20 deletions(-)
> >>
> >> diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> >> index 2bb4cabf802f..ee9c12cf3f08 100644
> >> --- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> >> +++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> >> @@ -400,28 +400,45 @@ static SUNXI_CCU_MP_WITH_MUX_GATE(nand_clk, "nand", mod0_default_parents, 0x080,
> >>                                 BIT(31),      /* gate */
> >>                                 0);
> >>
> >> +/*
> >> + * MMC clocks are the new timing mode (see A83T & H3) variety, but without
> >> + * the mode switch. This means they have a 2x post divider between the clock
> >> + * and the MMC module. This is not documented in the manual, but is taken
> >> + * into consideration when setting the mmc module clocks in the BSP kernel.
> >> + * Without it, MMC performance is degraded.
> >> + *
> >> + * We model it here to be consistent with other SoCs supporting this mode.
> >> + * The alternative would be to add the 2x multiplier when setting the MMC
> >> + * module clock in the MMC driver, just for the A64.
> >> + */
> >>  static const char * const mmc_default_parents[] = { "osc24M", "pll-periph0-2x",
> >>                                                   "pll-periph1-2x" };
> >> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc0_clk, "mmc0", mmc_default_parents, 0x088,
> >> -                               0, 4,         /* M */
> >> -                               16, 2,        /* P */
> >> -                               24, 2,        /* mux */
> >> -                               BIT(31),      /* gate */
> >> -                               0);
> >> -
> >> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc1_clk, "mmc1", mmc_default_parents, 0x08c,
> >> -                               0, 4,         /* M */
> >> -                               16, 2,        /* P */
> >> -                               24, 2,        /* mux */
> >> -                               BIT(31),      /* gate */
> >> -                               0);
> >> -
> >> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mmc_default_parents, 0x090,
> >> -                               0, 4,         /* M */
> >> -                               16, 2,        /* P */
> >> -                               24, 2,        /* mux */
> >> -                               BIT(31),      /* gate */
> >> -                               0);
> >> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc0_clk, "mmc0",
> >> +                                       mmc_default_parents, 0x088,
> >> +                                       0, 4,         /* M */
> >> +                                       16, 2,        /* P */
> >> +                                       24, 2,        /* mux */
> >> +                                       BIT(31),      /* gate */
> >> +                                       2,            /* post-div */
> >> +                                       0);
> >> +
> >> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc1_clk, "mmc1",
> >> +                                       mmc_default_parents, 0x08c,
> >> +                                       0, 4,         /* M */
> >> +                                       16, 2,        /* P */
> >> +                                       24, 2,        /* mux */
> >> +                                       BIT(31),      /* gate */
> >> +                                       2,            /* post-div */
> >> +                                       0);
> >> +
> >
> > Are you sure that the divider there for the non-eMMC clocks? Usually,
> > the new mode is only here for the eMMC, so we would divide the rate by
> > two in the non-eMMC case.
> 
> The new mode is there for all MMC controllers. The other two MMC
> controllers even have the old/new timing mode switch. In case you
> forgot we have ".need_new_timings" set for the A64 compatible.

But then, shouldn't we model them as such, using the work you did on
the A83t clocks?

> But to eliminate any doubts or concerns, I've rerun tests for the
> micro SD card, instead of the eMMC. And yes the results are the same,
> 2x improvement (12 MB/s vs 23.7 MB/s).

Ok, good.

Thanks!
Maxime
Chen-Yu Tsai Dec. 6, 2017, 4:10 p.m. UTC | #5
On Wed, Dec 6, 2017 at 11:56 PM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> Hi,
>
> On Wed, Dec 06, 2017 at 10:30:26AM +0800, Chen-Yu Tsai wrote:
>> On Wed, Dec 6, 2017 at 3:59 AM, Maxime Ripard
>> <maxime.ripard@free-electrons.com> wrote:
>> > Hi,
>> >
>> > On Mon, Dec 04, 2017 at 01:19:12PM +0800, Chen-Yu Tsai wrote:
>> >> On the A64, the MMC module clocks are fixed in the new timing mode,
>> >> i.e. they do not have a bit to select the mode. These clocks have
>> >> a 2x divider somewhere between the clock and the MMC module.
>> >>
>> >> To be consistent with other SoCs supporting the new timing mode,
>> >> we model the 2x divider as a fixed post-divider on the MMC module
>> >> clocks.
>> >>
>> >> This patch adds the post-dividers to the MMC clocks.
>> >>
>> >> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>> >
>> > I had a doubt applying that one... sorry.
>> >
>> >> ---
>> >>  drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 57 +++++++++++++++++++++++------------
>> >>  1 file changed, 37 insertions(+), 20 deletions(-)
>> >>
>> >> diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
>> >> index 2bb4cabf802f..ee9c12cf3f08 100644
>> >> --- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
>> >> +++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
>> >> @@ -400,28 +400,45 @@ static SUNXI_CCU_MP_WITH_MUX_GATE(nand_clk, "nand", mod0_default_parents, 0x080,
>> >>                                 BIT(31),      /* gate */
>> >>                                 0);
>> >>
>> >> +/*
>> >> + * MMC clocks are the new timing mode (see A83T & H3) variety, but without
>> >> + * the mode switch. This means they have a 2x post divider between the clock
>> >> + * and the MMC module. This is not documented in the manual, but is taken
>> >> + * into consideration when setting the mmc module clocks in the BSP kernel.
>> >> + * Without it, MMC performance is degraded.
>> >> + *
>> >> + * We model it here to be consistent with other SoCs supporting this mode.
>> >> + * The alternative would be to add the 2x multiplier when setting the MMC
>> >> + * module clock in the MMC driver, just for the A64.
>> >> + */
>> >>  static const char * const mmc_default_parents[] = { "osc24M", "pll-periph0-2x",
>> >>                                                   "pll-periph1-2x" };
>> >> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc0_clk, "mmc0", mmc_default_parents, 0x088,
>> >> -                               0, 4,         /* M */
>> >> -                               16, 2,        /* P */
>> >> -                               24, 2,        /* mux */
>> >> -                               BIT(31),      /* gate */
>> >> -                               0);
>> >> -
>> >> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc1_clk, "mmc1", mmc_default_parents, 0x08c,
>> >> -                               0, 4,         /* M */
>> >> -                               16, 2,        /* P */
>> >> -                               24, 2,        /* mux */
>> >> -                               BIT(31),      /* gate */
>> >> -                               0);
>> >> -
>> >> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mmc_default_parents, 0x090,
>> >> -                               0, 4,         /* M */
>> >> -                               16, 2,        /* P */
>> >> -                               24, 2,        /* mux */
>> >> -                               BIT(31),      /* gate */
>> >> -                               0);
>> >> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc0_clk, "mmc0",
>> >> +                                       mmc_default_parents, 0x088,
>> >> +                                       0, 4,         /* M */
>> >> +                                       16, 2,        /* P */
>> >> +                                       24, 2,        /* mux */
>> >> +                                       BIT(31),      /* gate */
>> >> +                                       2,            /* post-div */
>> >> +                                       0);
>> >> +
>> >> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc1_clk, "mmc1",
>> >> +                                       mmc_default_parents, 0x08c,
>> >> +                                       0, 4,         /* M */
>> >> +                                       16, 2,        /* P */
>> >> +                                       24, 2,        /* mux */
>> >> +                                       BIT(31),      /* gate */
>> >> +                                       2,            /* post-div */
>> >> +                                       0);
>> >> +
>> >
>> > Are you sure that the divider there for the non-eMMC clocks? Usually,
>> > the new mode is only here for the eMMC, so we would divide the rate by
>> > two in the non-eMMC case.
>>
>> The new mode is there for all MMC controllers. The other two MMC
>> controllers even have the old/new timing mode switch. In case you
>> forgot we have ".need_new_timings" set for the A64 compatible.
>
> But then, shouldn't we model them as such, using the work you did on
> the A83t clocks?

On the A64, the clocks don't have the switch. Only the MMC controller
does. On the A83T, both do.

ChenYu

>> But to eliminate any doubts or concerns, I've rerun tests for the
>> micro SD card, instead of the eMMC. And yes the results are the same,
>> 2x improvement (12 MB/s vs 23.7 MB/s).
>
> Ok, good.
>
> Thanks!
> Maxime
>
> --
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com
Maxime Ripard Dec. 7, 2017, 9:10 a.m. UTC | #6
On Thu, Dec 07, 2017 at 12:10:39AM +0800, Chen-Yu Tsai wrote:
> On Wed, Dec 6, 2017 at 11:56 PM, Maxime Ripard
> <maxime.ripard@free-electrons.com> wrote:
> > Hi,
> >
> > On Wed, Dec 06, 2017 at 10:30:26AM +0800, Chen-Yu Tsai wrote:
> >> On Wed, Dec 6, 2017 at 3:59 AM, Maxime Ripard
> >> <maxime.ripard@free-electrons.com> wrote:
> >> > Hi,
> >> >
> >> > On Mon, Dec 04, 2017 at 01:19:12PM +0800, Chen-Yu Tsai wrote:
> >> >> On the A64, the MMC module clocks are fixed in the new timing mode,
> >> >> i.e. they do not have a bit to select the mode. These clocks have
> >> >> a 2x divider somewhere between the clock and the MMC module.
> >> >>
> >> >> To be consistent with other SoCs supporting the new timing mode,
> >> >> we model the 2x divider as a fixed post-divider on the MMC module
> >> >> clocks.
> >> >>
> >> >> This patch adds the post-dividers to the MMC clocks.
> >> >>
> >> >> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> >> >
> >> > I had a doubt applying that one... sorry.
> >> >
> >> >> ---
> >> >>  drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 57 +++++++++++++++++++++++------------
> >> >>  1 file changed, 37 insertions(+), 20 deletions(-)
> >> >>
> >> >> diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> >> >> index 2bb4cabf802f..ee9c12cf3f08 100644
> >> >> --- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> >> >> +++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> >> >> @@ -400,28 +400,45 @@ static SUNXI_CCU_MP_WITH_MUX_GATE(nand_clk, "nand", mod0_default_parents, 0x080,
> >> >>                                 BIT(31),      /* gate */
> >> >>                                 0);
> >> >>
> >> >> +/*
> >> >> + * MMC clocks are the new timing mode (see A83T & H3) variety, but without
> >> >> + * the mode switch. This means they have a 2x post divider between the clock
> >> >> + * and the MMC module. This is not documented in the manual, but is taken
> >> >> + * into consideration when setting the mmc module clocks in the BSP kernel.
> >> >> + * Without it, MMC performance is degraded.
> >> >> + *
> >> >> + * We model it here to be consistent with other SoCs supporting this mode.
> >> >> + * The alternative would be to add the 2x multiplier when setting the MMC
> >> >> + * module clock in the MMC driver, just for the A64.
> >> >> + */
> >> >>  static const char * const mmc_default_parents[] = { "osc24M", "pll-periph0-2x",
> >> >>                                                   "pll-periph1-2x" };
> >> >> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc0_clk, "mmc0", mmc_default_parents, 0x088,
> >> >> -                               0, 4,         /* M */
> >> >> -                               16, 2,        /* P */
> >> >> -                               24, 2,        /* mux */
> >> >> -                               BIT(31),      /* gate */
> >> >> -                               0);
> >> >> -
> >> >> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc1_clk, "mmc1", mmc_default_parents, 0x08c,
> >> >> -                               0, 4,         /* M */
> >> >> -                               16, 2,        /* P */
> >> >> -                               24, 2,        /* mux */
> >> >> -                               BIT(31),      /* gate */
> >> >> -                               0);
> >> >> -
> >> >> -static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mmc_default_parents, 0x090,
> >> >> -                               0, 4,         /* M */
> >> >> -                               16, 2,        /* P */
> >> >> -                               24, 2,        /* mux */
> >> >> -                               BIT(31),      /* gate */
> >> >> -                               0);
> >> >> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc0_clk, "mmc0",
> >> >> +                                       mmc_default_parents, 0x088,
> >> >> +                                       0, 4,         /* M */
> >> >> +                                       16, 2,        /* P */
> >> >> +                                       24, 2,        /* mux */
> >> >> +                                       BIT(31),      /* gate */
> >> >> +                                       2,            /* post-div */
> >> >> +                                       0);
> >> >> +
> >> >> +static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc1_clk, "mmc1",
> >> >> +                                       mmc_default_parents, 0x08c,
> >> >> +                                       0, 4,         /* M */
> >> >> +                                       16, 2,        /* P */
> >> >> +                                       24, 2,        /* mux */
> >> >> +                                       BIT(31),      /* gate */
> >> >> +                                       2,            /* post-div */
> >> >> +                                       0);
> >> >> +
> >> >
> >> > Are you sure that the divider there for the non-eMMC clocks? Usually,
> >> > the new mode is only here for the eMMC, so we would divide the rate by
> >> > two in the non-eMMC case.
> >>
> >> The new mode is there for all MMC controllers. The other two MMC
> >> controllers even have the old/new timing mode switch. In case you
> >> forgot we have ".need_new_timings" set for the A64 compatible.
> >
> > But then, shouldn't we model them as such, using the work you did on
> > the A83t clocks?
> 
> On the A64, the clocks don't have the switch. Only the MMC controller
> does. On the A83T, both do.

Ah, right. I've applied both patches.

Maxime
diff mbox

Patch

diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
index 2bb4cabf802f..ee9c12cf3f08 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
@@ -400,28 +400,45 @@  static SUNXI_CCU_MP_WITH_MUX_GATE(nand_clk, "nand", mod0_default_parents, 0x080,
 				  BIT(31),	/* gate */
 				  0);
 
+/*
+ * MMC clocks are the new timing mode (see A83T & H3) variety, but without
+ * the mode switch. This means they have a 2x post divider between the clock
+ * and the MMC module. This is not documented in the manual, but is taken
+ * into consideration when setting the mmc module clocks in the BSP kernel.
+ * Without it, MMC performance is degraded.
+ *
+ * We model it here to be consistent with other SoCs supporting this mode.
+ * The alternative would be to add the 2x multiplier when setting the MMC
+ * module clock in the MMC driver, just for the A64.
+ */
 static const char * const mmc_default_parents[] = { "osc24M", "pll-periph0-2x",
 						    "pll-periph1-2x" };
-static SUNXI_CCU_MP_WITH_MUX_GATE(mmc0_clk, "mmc0", mmc_default_parents, 0x088,
-				  0, 4,		/* M */
-				  16, 2,	/* P */
-				  24, 2,	/* mux */
-				  BIT(31),	/* gate */
-				  0);
-
-static SUNXI_CCU_MP_WITH_MUX_GATE(mmc1_clk, "mmc1", mmc_default_parents, 0x08c,
-				  0, 4,		/* M */
-				  16, 2,	/* P */
-				  24, 2,	/* mux */
-				  BIT(31),	/* gate */
-				  0);
-
-static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mmc_default_parents, 0x090,
-				  0, 4,		/* M */
-				  16, 2,	/* P */
-				  24, 2,	/* mux */
-				  BIT(31),	/* gate */
-				  0);
+static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc0_clk, "mmc0",
+					  mmc_default_parents, 0x088,
+					  0, 4,		/* M */
+					  16, 2,	/* P */
+					  24, 2,	/* mux */
+					  BIT(31),	/* gate */
+					  2,		/* post-div */
+					  0);
+
+static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc1_clk, "mmc1",
+					  mmc_default_parents, 0x08c,
+					  0, 4,		/* M */
+					  16, 2,	/* P */
+					  24, 2,	/* mux */
+					  BIT(31),	/* gate */
+					  2,		/* post-div */
+					  0);
+
+static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc2_clk, "mmc2",
+					  mmc_default_parents, 0x090,
+					  0, 4,		/* M */
+					  16, 2,	/* P */
+					  24, 2,	/* mux */
+					  BIT(31),	/* gate */
+					  2,		/* post-div */
+					  0);
 
 static const char * const ts_parents[] = { "osc24M", "pll-periph0", };
 static SUNXI_CCU_MP_WITH_MUX_GATE(ts_clk, "ts", ts_parents, 0x098,