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From: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
To: Luc Michel <luc@lmichel.fr>
Cc: Peter Maydell <peter.maydell@linaro.org>,
	qemu-arm@nongnu.org, qemu-devel@nongnu.org,
	Andrew Baumann <Andrew.Baumann@microsoft.com>
Subject: Re: [PATCH 04/14] hw/arm/raspi: add a skeleton implementation of the cprman
Date: Sat, 3 Oct 2020 20:14:15 +0200	[thread overview]
Message-ID: <dfb488db-afa4-d307-cac1-ce71e5ebf29a@amsat.org> (raw)
In-Reply-To: <20201003115444.m2woqcpit34vfv3u@sekoia-pc.home.lmichel.fr>

On 10/3/20 1:54 PM, Luc Michel wrote:
> On 16:37 Fri 02 Oct     , Philippe Mathieu-Daudé wrote:
> 
> [snip]
> 
>>>>> +struct BCM2835CprmanState {
>>>>> +    /*< private >*/
>>>>> +    SysBusDevice parent_obj;
>>>>> +
>>>>> +    /*< public >*/
>>>>> +    MemoryRegion iomem;
>>>>> +
>>>>> +    uint32_t regs[CPRMAN_NUM_REGS];
>>>>> +    uint32_t xosc_freq;
>>>>> +
>>>>> +    Clock *xosc;
>>
>> Isn't it xosc external to the CPRMAN?
>>
> Yes on real hardware I'm pretty sure it's the oscillator we can see on
> the board itself, near the SoC (on the bottom side). This is how I first
> planned to implement it. I then realized that would add complexity to
> the BCM2835Peripherals model for no good reasons IMHO (mainly because of
> migration). So at the end I put it inside the CPRMAN for simplicity, and
> added a property to set its frequency.

OK as long as all boards have a 19.2MHz crystal, but if the property
is not easily accessible why not use a #define in
"hw/arm/raspi_platform.h" instead?

Else we should alias the property using object_property_add_alias()
in TYPE_BCM2835_PERIPHERALS.

> 
>>>>> +};
> 
> [snip]
> 
>>>>> +static const MemoryRegionOps cprman_ops = {
>>>>> +    .read = cprman_read,
>>>>> +    .write = cprman_write,
>>>>> +    .endianness = DEVICE_LITTLE_ENDIAN,
>>>>> +    .valid      = {
>>>>> +        .min_access_size        = 4,
>>>>> +        .max_access_size        = 4,
>>>>
>>>> I couldn't find this in the public datasheets (any pointer?).
>>>>
>>>> Since your implementation is 32bit, can you explicit .impl
>>>> min/max = 4?
>>>
>>> I could not find this information either, but I assumed this is the
>>> case, mainly because of the 'PASSWORD' field in all registers.
>>
>> Good point. Do you mind adding a comment about it here please?
>>
> 
> OK
> 
>>>
>>> Regarding .impl, I thought that having .valid was enough?
>>
>> Until we eventually figure out we can do 64-bit accesses,
>> so someone change .valid.max to 8 and your model is broken :/
> 
> OK, I'll add the .impl constraints.
> 
> [snip]
> 


  reply	other threads:[~2020-10-03 18:15 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 [this message]
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
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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