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From: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
To: Luc Michel <luc@lmichel.fr>, qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
	qemu-arm@nongnu.org,
	Andrew Baumann <Andrew.Baumann@microsoft.com>
Subject: Re: [PATCH 09/14] hw/misc/bcm2835_cprman: add a clock mux skeleton implementation
Date: Fri, 2 Oct 2020 17:34:51 +0200	[thread overview]
Message-ID: <d758d149-bca5-e52f-8d1f-65caf742a136@amsat.org> (raw)
In-Reply-To: <2a18bb94-1e6c-d853-3e6e-f6874b617a2b@amsat.org>

On 10/2/20 4:42 PM, Philippe Mathieu-Daudé wrote:
> On 9/25/20 12:17 PM, Luc Michel wrote:
>> The clock multiplexers are the last clock stage in the cprman. Each mux
>> outputs one clock signal that goes out of the cprman to the SoC
>> peripherals.
>>
>> Each mux has at most 10 sources. The sources 0 to 3 are common to all
>> muxes. They are:
>>    0. ground (no clock signal)
>>    1. the main oscillator (xosc)
>>    2. "test debug 0" clock
>>    3. "test debug 1" clock
>>
>> Test debug 0 and 1 are actual clock muxes that can be used as sources to
>> other muxes (for debug purpose).
>>
>> Sources 4 to 9 are mux specific and can be unpopulated (grounded). Those
>> sources are fed by the PLL channels outputs.
>>
>> One corner case exists for DSI0E and DSI0P muxes. They have their source
>> number 4 connected to an intermediate multiplexer that can select
>> between PLLA-DSI0 and PLLD-DSI0 channel. This multiplexer is called
>> DSI0HSCK and is not a clock mux as such. It is really a simple mux from
>> the hardware point of view (see https://elinux.org/The_Undocumented_Pi).
>> This mux is not implemented in this commit.
>>
>> Note that there is some muxes for which sources are unknown (because of
>> a lack of documentation). For those cases all the sources are connected
>> to ground in this implementation.
>>
>> Each clock mux output is exported by the cprman at the qdev level,
>> adding the suffix '-out' to the mux name to form the output clock name.
>> (E.g. the 'uart' mux sees its output exported as 'uart-out' at the
>> cprman level.)
>>
>> Signed-off-by: Luc Michel <luc@lmichel.fr>
>> ---
[...]
>>  struct BCM2835CprmanState {
>>      /*< private >*/
>>      SysBusDevice parent_obj;
>>  
>>      /*< public >*/
>>      MemoryRegion iomem;
>>  
>>      CprmanPLLState plls[CPRMAN_NUM_PLL];
>>      CprmanPLLChannelState channels[CPRMAN_NUM_PLL_CHANNEL];
>> +    CprmanClockMuxState clock_muxes[CPRMAN_NUM_CLOCK_MUX];
>>  
>>      uint32_t regs[CPRMAN_NUM_REGS];
>>      uint32_t xosc_freq;
>>  
>>      Clock *xosc;
>> +    Clock *gnd;
> 
> This one seems to belong to MachineState in "hw/boards.h".

Although it might be easier to have a singleton in hw/core/clock.c...


  reply	other threads:[~2020-10-02 15:38 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-25 10:17 [PATCH 00/14] raspi: add the bcm2835 cprman clock manager Luc Michel
2020-09-25 10:17 ` [PATCH 01/14] hw/core/clock: provide the VMSTATE_ARRAY_CLOCK macro Luc Michel
2020-09-26 20:36   ` Philippe Mathieu-Daudé
2020-09-28  8:38   ` Damien Hedde
2020-09-25 10:17 ` [PATCH 02/14] hw/core/clock: trace clock values in Hz instead of ns Luc Michel
2020-09-26 20:36   ` Philippe Mathieu-Daudé
2020-09-28  8:42     ` Damien Hedde
2020-09-25 10:17 ` [PATCH 03/14] hw/arm/raspi: fix cprman base address Luc Michel
2020-09-26 21:04   ` Philippe Mathieu-Daudé
2020-09-25 10:17 ` [PATCH 04/14] hw/arm/raspi: add a skeleton implementation of the cprman Luc Michel
2020-09-26 21:05   ` Philippe Mathieu-Daudé
2020-09-28  8:45     ` Luc Michel
2020-10-02 14:37       ` Philippe Mathieu-Daudé
2020-10-03 11:54         ` Luc Michel
2020-10-03 18:14           ` Philippe Mathieu-Daudé
2020-09-25 10:17 ` [PATCH 05/14] hw/misc/bcm2835_cprman: add a PLL skeleton implementation Luc Michel
2020-09-26 21:17   ` Philippe Mathieu-Daudé
2020-09-25 10:17 ` [PATCH 06/14] hw/misc/bcm2835_cprman: implement PLLs behaviour Luc Michel
2020-09-26 21:26   ` Philippe Mathieu-Daudé
2020-09-25 10:17 ` [PATCH 07/14] hw/misc/bcm2835_cprman: add a PLL channel skeleton implementation Luc Michel
2020-09-26 21:32   ` Philippe Mathieu-Daudé
2020-09-25 10:17 ` [PATCH 08/14] hw/misc/bcm2835_cprman: implement PLL channels behaviour Luc Michel
2020-09-26 21:36   ` Philippe Mathieu-Daudé
2020-09-25 10:17 ` [PATCH 09/14] hw/misc/bcm2835_cprman: add a clock mux skeleton implementation Luc Michel
2020-10-02 14:42   ` Philippe Mathieu-Daudé
2020-10-02 15:34     ` Philippe Mathieu-Daudé [this message]
2020-10-04 19:34     ` Luc Michel
2020-10-04 20:17       ` Philippe Mathieu-Daudé
2020-09-25 10:17 ` [PATCH 10/14] hw/misc/bcm2835_cprman: implement clock mux behaviour Luc Michel
2020-09-26 21:40   ` Philippe Mathieu-Daudé
2020-10-02 14:51     ` Philippe Mathieu-Daudé
2020-10-04 18:37       ` Luc Michel
2020-10-05 19:50         ` Luc Michel
2020-09-25 10:17 ` [PATCH 11/14] hw/misc/bcm2835_cprman: add the DSI0HSCK multiplexer Luc Michel
2020-10-02 14:55   ` Philippe Mathieu-Daudé
2020-09-25 10:17 ` [PATCH 12/14] hw/misc/bcm2835_cprman: add sane reset values to the registers Luc Michel
2020-09-25 10:17 ` [RFC PATCH 13/14] hw/char/pl011: add a clock input Luc Michel
2020-09-25 10:36   ` Philippe Mathieu-Daudé
2020-09-25 10:17 ` [RFC PATCH 14/14] hw/arm/bcm2835_peripherals: connect the UART clock Luc Michel
2020-09-25 11:56 ` [PATCH 00/14] raspi: add the bcm2835 cprman clock manager no-reply
2020-09-25 12:55 ` Philippe Mathieu-Daudé

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