[v1] raspi: add the bcm2835 cprman clock manager

[PATCH 10/14] hw/misc/bcm2835_cprman: implement clock mux behaviour

Posted by Luc Michel 5 years, 4 months ago

A clock mux can be configured to select one of its 10 sources through
the cm_ctl register. It also embeds yet another clock divider, composed
of an integer part and a fractionnal part. The number of bits of each
part is mux dependant.

Signed-off-by: Luc Michel <luc@lmichel.fr>
---
 hw/misc/bcm2835_cprman.c | 43 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/hw/misc/bcm2835_cprman.c b/hw/misc/bcm2835_cprman.c
index 8df2db0fd9..75bc11939b 100644
--- a/hw/misc/bcm2835_cprman.c
+++ b/hw/misc/bcm2835_cprman.c
@@ -229,19 +229,60 @@ static const TypeInfo cprman_pll_channel_info = {
 };
 
 
 /* clock mux */
 
+static bool clock_mux_is_enabled(CprmanClockMuxState *mux)
+{
+    return FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, ENABLE);
+}
+
 static void clock_mux_update(CprmanClockMuxState *mux)
 {
-    clock_update(mux->out, 0);
+    uint64_t freq, div;
+    uint32_t src = FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, SRC);
+    bool enabled = clock_mux_is_enabled(mux);
+
+    *mux->reg_cm = FIELD_DP32(*mux->reg_cm, CM_CLOCKx_CTL, BUSY, enabled);
+
+    if (!enabled) {
+        clock_update(mux->out, 0);
+        return;
+    }
+
+    freq = clock_get_hz(mux->srcs[src]);
+
+    if (mux->int_bits == 0 && mux->frac_bits == 0) {
+        clock_update_hz(mux->out, freq);
+        return;
+    }
+
+    /*
+     * The divider has an integer and a fractional part. The size of each part
+     * varies with the muxes (int_bits and frac_bits). Both parts are
+     * concatenated, with the integer part always starting at bit 12.
+     */
+    div = mux->reg_cm[1] >> (R_CM_CLOCKx_DIV_FRAC_LENGTH - mux->frac_bits);
+    div &= (1 << (mux->int_bits + mux->frac_bits)) - 1;
+
+    freq = (freq << mux->frac_bits) / div;
+
+    clock_update_hz(mux->out, freq);
 }
 
 static void clock_mux_src_update(void *opaque)
 {
     CprmanClockMuxState **backref = opaque;
     CprmanClockMuxState *s = *backref;
+    CprmanClockMuxSource src = backref - s->backref;
+    uint32_t current_src;
+
+    current_src = FIELD_EX32(*s->reg_cm, CM_CLOCKx_CTL, SRC);
+
+    if (current_src != src) {
+        return;
+    }
 
     clock_mux_update(s);
 }
 
 static void clock_mux_init(Object *obj)
-- 
2.28.0

Re: [PATCH 10/14] hw/misc/bcm2835_cprman: implement clock mux behaviour

Posted by Philippe Mathieu-Daudé 5 years, 4 months ago

On 9/25/20 12:17 PM, Luc Michel wrote:
> A clock mux can be configured to select one of its 10 sources through
> the cm_ctl register. It also embeds yet another clock divider, composed
> of an integer part and a fractionnal part. The number of bits of each

Typo "fractional".

> part is mux dependant.

Typo "dependent"?

> 
> Signed-off-by: Luc Michel <luc@lmichel.fr>
> ---
>  hw/misc/bcm2835_cprman.c | 43 +++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 42 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/misc/bcm2835_cprman.c b/hw/misc/bcm2835_cprman.c
> index 8df2db0fd9..75bc11939b 100644
> --- a/hw/misc/bcm2835_cprman.c
> +++ b/hw/misc/bcm2835_cprman.c
> @@ -229,19 +229,60 @@ static const TypeInfo cprman_pll_channel_info = {
>  };
>  
>  
>  /* clock mux */
>  
> +static bool clock_mux_is_enabled(CprmanClockMuxState *mux)
> +{
> +    return FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, ENABLE);
> +}
> +
>  static void clock_mux_update(CprmanClockMuxState *mux)
>  {
> -    clock_update(mux->out, 0);
> +    uint64_t freq, div;
> +    uint32_t src = FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, SRC);
> +    bool enabled = clock_mux_is_enabled(mux);
> +
> +    *mux->reg_cm = FIELD_DP32(*mux->reg_cm, CM_CLOCKx_CTL, BUSY, enabled);
> +
> +    if (!enabled) {
> +        clock_update(mux->out, 0);
> +        return;
> +    }
> +
> +    freq = clock_get_hz(mux->srcs[src]);
> +
> +    if (mux->int_bits == 0 && mux->frac_bits == 0) {
> +        clock_update_hz(mux->out, freq);
> +        return;
> +    }
> +
> +    /*
> +     * The divider has an integer and a fractional part. The size of each part
> +     * varies with the muxes (int_bits and frac_bits). Both parts are
> +     * concatenated, with the integer part always starting at bit 12.
> +     */
> +    div = mux->reg_cm[1] >> (R_CM_CLOCKx_DIV_FRAC_LENGTH - mux->frac_bits);
> +    div &= (1 << (mux->int_bits + mux->frac_bits)) - 1;
> +
> +    freq = (freq << mux->frac_bits) / div;
> +
> +    clock_update_hz(mux->out, freq);
>  }
>  
>  static void clock_mux_src_update(void *opaque)
>  {
>      CprmanClockMuxState **backref = opaque;
>      CprmanClockMuxState *s = *backref;
> +    CprmanClockMuxSource src = backref - s->backref;
> +    uint32_t current_src;
> +
> +    current_src = FIELD_EX32(*s->reg_cm, CM_CLOCKx_CTL, SRC);
> +
> +    if (current_src != src) {
> +        return;
> +    }
>  
>      clock_mux_update(s);
>  }
>  
>  static void clock_mux_init(Object *obj)
>

Re: [PATCH 10/14] hw/misc/bcm2835_cprman: implement clock mux behaviour

Posted by Philippe Mathieu-Daudé 5 years, 4 months ago

On 9/26/20 11:40 PM, Philippe Mathieu-Daudé wrote:
> On 9/25/20 12:17 PM, Luc Michel wrote:
>> A clock mux can be configured to select one of its 10 sources through
>> the cm_ctl register. It also embeds yet another clock divider, composed
>> of an integer part and a fractionnal part. The number of bits of each
> 
> Typo "fractional".
> 
>> part is mux dependant.
> 
> Typo "dependent"?
> 
>>
>> Signed-off-by: Luc Michel <luc@lmichel.fr>
>> ---
>>  hw/misc/bcm2835_cprman.c | 43 +++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 42 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/misc/bcm2835_cprman.c b/hw/misc/bcm2835_cprman.c
>> index 8df2db0fd9..75bc11939b 100644
>> --- a/hw/misc/bcm2835_cprman.c
>> +++ b/hw/misc/bcm2835_cprman.c
>> @@ -229,19 +229,60 @@ static const TypeInfo cprman_pll_channel_info = {
>>  };
>>  
>>  
>>  /* clock mux */
>>  
>> +static bool clock_mux_is_enabled(CprmanClockMuxState *mux)
>> +{
>> +    return FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, ENABLE);
>> +}
>> +
>>  static void clock_mux_update(CprmanClockMuxState *mux)
>>  {
>> -    clock_update(mux->out, 0);
>> +    uint64_t freq, div;
>> +    uint32_t src = FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, SRC);
>> +    bool enabled = clock_mux_is_enabled(mux);
>> +
>> +    *mux->reg_cm = FIELD_DP32(*mux->reg_cm, CM_CLOCKx_CTL, BUSY, enabled);
>> +
>> +    if (!enabled) {
>> +        clock_update(mux->out, 0);
>> +        return;
>> +    }
>> +
>> +    freq = clock_get_hz(mux->srcs[src]);
>> +
>> +    if (mux->int_bits == 0 && mux->frac_bits == 0) {
>> +        clock_update_hz(mux->out, freq);
>> +        return;
>> +    }
>> +
>> +    /*
>> +     * The divider has an integer and a fractional part. The size of each part
>> +     * varies with the muxes (int_bits and frac_bits). Both parts are
>> +     * concatenated, with the integer part always starting at bit 12.
>> +     */
>> +    div = mux->reg_cm[1] >> (R_CM_CLOCKx_DIV_FRAC_LENGTH - mux->frac_bits);
>> +    div &= (1 << (mux->int_bits + mux->frac_bits)) - 1;

Eventually:

    div &= MAKE_64BIT_MASK(mux->int_bits + mux->frac_bits, 64);

>> +
>> +    freq = (freq << mux->frac_bits) / div;

Maybe:

    freq = muldiv64(freq, 1 << mux->frac_bits, div);

>> +
>> +    clock_update_hz(mux->out, freq);
>>  }
>>  
>>  static void clock_mux_src_update(void *opaque)
>>  {
>>      CprmanClockMuxState **backref = opaque;
>>      CprmanClockMuxState *s = *backref;
>> +    CprmanClockMuxSource src = backref - s->backref;
>> +    uint32_t current_src;

Maybe avoid current_src and use in place.

Otherwise:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

>> +
>> +    current_src = FIELD_EX32(*s->reg_cm, CM_CLOCKx_CTL, SRC);
>> +
>> +    if (current_src != src) {
>> +        return;
>> +    }
>>  
>>      clock_mux_update(s);
>>  }
>>  
>>  static void clock_mux_init(Object *obj)
>>
>

Re: [PATCH 10/14] hw/misc/bcm2835_cprman: implement clock mux behaviour

Posted by Luc Michel 5 years, 4 months ago

On 16:51 Fri 02 Oct     , Philippe Mathieu-Daudé wrote:
> On 9/26/20 11:40 PM, Philippe Mathieu-Daudé wrote:
> > On 9/25/20 12:17 PM, Luc Michel wrote:
> >> A clock mux can be configured to select one of its 10 sources through
> >> the cm_ctl register. It also embeds yet another clock divider, composed
> >> of an integer part and a fractionnal part. The number of bits of each
> > 
> > Typo "fractional".
> > 
> >> part is mux dependant.
> > 
> > Typo "dependent"?
> > 
> >>
> >> Signed-off-by: Luc Michel <luc@lmichel.fr>
> >> ---
> >>  hw/misc/bcm2835_cprman.c | 43 +++++++++++++++++++++++++++++++++++++++-
> >>  1 file changed, 42 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/hw/misc/bcm2835_cprman.c b/hw/misc/bcm2835_cprman.c
> >> index 8df2db0fd9..75bc11939b 100644
> >> --- a/hw/misc/bcm2835_cprman.c
> >> +++ b/hw/misc/bcm2835_cprman.c
> >> @@ -229,19 +229,60 @@ static const TypeInfo cprman_pll_channel_info = {
> >>  };
> >>  
> >>  
> >>  /* clock mux */
> >>  
> >> +static bool clock_mux_is_enabled(CprmanClockMuxState *mux)
> >> +{
> >> +    return FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, ENABLE);
> >> +}
> >> +
> >>  static void clock_mux_update(CprmanClockMuxState *mux)
> >>  {
> >> -    clock_update(mux->out, 0);
> >> +    uint64_t freq, div;
> >> +    uint32_t src = FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, SRC);
> >> +    bool enabled = clock_mux_is_enabled(mux);
> >> +
> >> +    *mux->reg_cm = FIELD_DP32(*mux->reg_cm, CM_CLOCKx_CTL, BUSY, enabled);
> >> +
> >> +    if (!enabled) {
> >> +        clock_update(mux->out, 0);
> >> +        return;
> >> +    }
> >> +
> >> +    freq = clock_get_hz(mux->srcs[src]);
> >> +
> >> +    if (mux->int_bits == 0 && mux->frac_bits == 0) {
> >> +        clock_update_hz(mux->out, freq);
> >> +        return;
> >> +    }
> >> +
> >> +    /*
> >> +     * The divider has an integer and a fractional part. The size of each part
> >> +     * varies with the muxes (int_bits and frac_bits). Both parts are
> >> +     * concatenated, with the integer part always starting at bit 12.
> >> +     */
> >> +    div = mux->reg_cm[1] >> (R_CM_CLOCKx_DIV_FRAC_LENGTH - mux->frac_bits);
> >> +    div &= (1 << (mux->int_bits + mux->frac_bits)) - 1;
> 
> Eventually:
> 
>     div &= MAKE_64BIT_MASK(mux->int_bits + mux->frac_bits, 64);
I think this is MAKE_64BIT_MASK(0, mux->int_bits + mux->frac_bits)
(The shift macro parameter is 0 to have the ones positioned at the
mask's LSBs.
I'll use this macro in my next re-roll.

> 
> >> +
> >> +    freq = (freq << mux->frac_bits) / div;
> 
> Maybe:
> 
>     freq = muldiv64(freq, 1 << mux->frac_bits, div);
OK

> 
> >> +
> >> +    clock_update_hz(mux->out, freq);
> >>  }
> >>  
> >>  static void clock_mux_src_update(void *opaque)
> >>  {
> >>      CprmanClockMuxState **backref = opaque;
> >>      CprmanClockMuxState *s = *backref;
> >> +    CprmanClockMuxSource src = backref - s->backref;
> >> +    uint32_t current_src;
> 
> Maybe avoid current_src and use in place.
OK

> 
> Otherwise:
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Thanks !

-- 
Luc

> 
> >> +
> >> +    current_src = FIELD_EX32(*s->reg_cm, CM_CLOCKx_CTL, SRC);
> >> +
> >> +    if (current_src != src) {
> >> +        return;
> >> +    }
> >>  
> >>      clock_mux_update(s);
> >>  }
> >>  
> >>  static void clock_mux_init(Object *obj)
> >>
> > 

--

Re: [PATCH 10/14] hw/misc/bcm2835_cprman: implement clock mux behaviour

Posted by Luc Michel 5 years, 4 months ago

On 20:37 Sun 04 Oct     , Luc Michel wrote:
> On 16:51 Fri 02 Oct     , Philippe Mathieu-Daudé wrote:
> > On 9/26/20 11:40 PM, Philippe Mathieu-Daudé wrote:
> > > On 9/25/20 12:17 PM, Luc Michel wrote:
> > >> A clock mux can be configured to select one of its 10 sources through
> > >> the cm_ctl register. It also embeds yet another clock divider, composed
> > >> of an integer part and a fractionnal part. The number of bits of each
> > > 
> > > Typo "fractional".
> > > 
> > >> part is mux dependant.
> > > 
> > > Typo "dependent"?
> > > 
> > >>
> > >> Signed-off-by: Luc Michel <luc@lmichel.fr>
> > >> ---
> > >>  hw/misc/bcm2835_cprman.c | 43 +++++++++++++++++++++++++++++++++++++++-
> > >>  1 file changed, 42 insertions(+), 1 deletion(-)
> > >>
> > >> diff --git a/hw/misc/bcm2835_cprman.c b/hw/misc/bcm2835_cprman.c
> > >> index 8df2db0fd9..75bc11939b 100644
> > >> --- a/hw/misc/bcm2835_cprman.c
> > >> +++ b/hw/misc/bcm2835_cprman.c
> > >> @@ -229,19 +229,60 @@ static const TypeInfo cprman_pll_channel_info = {
> > >>  };
> > >>  
> > >>  
> > >>  /* clock mux */
> > >>  
> > >> +static bool clock_mux_is_enabled(CprmanClockMuxState *mux)
> > >> +{
> > >> +    return FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, ENABLE);
> > >> +}
> > >> +
> > >>  static void clock_mux_update(CprmanClockMuxState *mux)
> > >>  {
> > >> -    clock_update(mux->out, 0);
> > >> +    uint64_t freq, div;
> > >> +    uint32_t src = FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, SRC);
> > >> +    bool enabled = clock_mux_is_enabled(mux);
> > >> +
> > >> +    *mux->reg_cm = FIELD_DP32(*mux->reg_cm, CM_CLOCKx_CTL, BUSY, enabled);
> > >> +
> > >> +    if (!enabled) {
> > >> +        clock_update(mux->out, 0);
> > >> +        return;
> > >> +    }
> > >> +
> > >> +    freq = clock_get_hz(mux->srcs[src]);
> > >> +
> > >> +    if (mux->int_bits == 0 && mux->frac_bits == 0) {
> > >> +        clock_update_hz(mux->out, freq);
> > >> +        return;
> > >> +    }
> > >> +
> > >> +    /*
> > >> +     * The divider has an integer and a fractional part. The size of each part
> > >> +     * varies with the muxes (int_bits and frac_bits). Both parts are
> > >> +     * concatenated, with the integer part always starting at bit 12.
> > >> +     */
> > >> +    div = mux->reg_cm[1] >> (R_CM_CLOCKx_DIV_FRAC_LENGTH - mux->frac_bits);
> > >> +    div &= (1 << (mux->int_bits + mux->frac_bits)) - 1;
> > 
> > Eventually:
> > 
> >     div &= MAKE_64BIT_MASK(mux->int_bits + mux->frac_bits, 64);
> I think this is MAKE_64BIT_MASK(0, mux->int_bits + mux->frac_bits)
> (The shift macro parameter is 0 to have the ones positioned at the
> mask's LSBs.
> I'll use this macro in my next re-roll.
Actually, I won't, because switching to muldiv64 implied some
modifications. The muldiv64 divisor parameter is uint32_t. Since there
is no MAKE_32BIT_MASK, and I don't use all the "features" of this macro
anyway (shift = 0 in my case), I'll keep this form (but I'll switch to
uin32_t for div).

-- 
Luc

> 
> > 
> > >> +
> > >> +    freq = (freq << mux->frac_bits) / div;
> > 
> > Maybe:
> > 
> >     freq = muldiv64(freq, 1 << mux->frac_bits, div);
> OK
> 
> > 
> > >> +
> > >> +    clock_update_hz(mux->out, freq);
> > >>  }
> > >>  
> > >>  static void clock_mux_src_update(void *opaque)
> > >>  {
> > >>      CprmanClockMuxState **backref = opaque;
> > >>      CprmanClockMuxState *s = *backref;
> > >> +    CprmanClockMuxSource src = backref - s->backref;
> > >> +    uint32_t current_src;
> > 
> > Maybe avoid current_src and use in place.
> OK
> 
> > 
> > Otherwise:
> > Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Thanks !
> 
> -- 
> Luc
> 
> > 
> > >> +
> > >> +    current_src = FIELD_EX32(*s->reg_cm, CM_CLOCKx_CTL, SRC);
> > >> +
> > >> +    if (current_src != src) {
> > >> +        return;
> > >> +    }
> > >>  
> > >>      clock_mux_update(s);
> > >>  }
> > >>  
> > >>  static void clock_mux_init(Object *obj)
> > >>
> > > 
> 
> -- 

--