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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-devel@nongnu.org,
	Andrew Baumann <Andrew.Baumann@microsoft.com>,
	Paul Zimmerman <pauldzim@gmail.com>,
	Niek Linnenbank <nieklinnenbank@gmail.com>,
	qemu-arm@nongnu.org, Havard Skinnemoen <hskinnemoen@google.com>
Subject: Re: [PATCH v3 13/15] hw/misc/bcm2835_cprman: add sane reset values to the registers
Date: Mon, 19 Oct 2020 17:44:52 +0200	[thread overview]
Message-ID: <98d573dc-1e43-17e8-97b6-6f8a869f65e2@amsat.org> (raw)
In-Reply-To: <473818a2-b267-881f-b827-425a384a27bd@amsat.org>

On 10/16/20 7:10 PM, Philippe Mathieu-Daudé wrote:
> On 10/11/20 8:26 PM, Luc Michel wrote:
>> On 18:18 Sat 10 Oct     , Philippe Mathieu-Daudé wrote:
>>> On 10/10/20 3:57 PM, Luc Michel wrote:
>>>> Those reset values have been extracted from a Raspberry Pi 3 model B
>>>> v1.2, using the 2020-08-20 version of raspios. The dump was done using
>>>> the debugfs interface of the CPRMAN driver in Linux (under
>>>> '/sys/kernel/debug/clk'). Each exposed clock tree stage (PLLs, channels
>>>> and muxes) can be observed by reading the 'regdump' file (e.g.
>>>> 'plla/regdump').
>>>>
>>>> Those values are set by the Raspberry Pi firmware at boot time (Linux
>>>> expects them to be set when it boots up).
>>>>
>>>> Some stages are not exposed by the Linux driver (e.g. the PLL B). For
>>>> those, the reset values are unknown and left to 0 which implies a
>>>> disabled output.
>>>>
>>>> Once booted in QEMU, the final clock tree is very similar to the one
>>>> visible on real hardware. The differences come from some unimplemented
>>>> devices for which the driver simply disable the corresponding clock.
>>>>
>>>> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>>>> Signed-off-by: Luc Michel <luc@lmichel.fr>
>>>> ---
>>>>    include/hw/misc/bcm2835_cprman_internals.h | 269 
>>>> +++++++++++++++++++++
>>>>    hw/misc/bcm2835_cprman.c                   |  31 +++
>>>>    2 files changed, 300 insertions(+)
[...]

I haven't verified the dumped values with real hardware,
but for the rest this patch shouldn't introduce regression,
and it helps to boot up to Linux kernel 5.7, so:

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


  reply	other threads:[~2020-10-19 15:47 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-10 13:57 [PATCH v3 00/15] raspi: add the bcm2835 cprman clock manager Luc Michel
2020-10-10 13:57 ` [PATCH v3 01/15] hw/core/clock: provide the VMSTATE_ARRAY_CLOCK macro Luc Michel
2020-10-10 13:57 ` [PATCH v3 02/15] hw/core/clock: trace clock values in Hz instead of ns Luc Michel
2020-10-10 15:48   ` Philippe Mathieu-Daudé
2020-10-10 13:57 ` [PATCH v3 03/15] hw/core/clock: add the clock_new helper function Luc Michel
2020-10-10 15:17   ` Philippe Mathieu-Daudé
2020-10-10 15:44     ` Philippe Mathieu-Daudé
2020-10-10 13:57 ` [PATCH v3 04/15] hw/arm/raspi: fix CPRMAN base address Luc Michel
2020-10-10 13:57 ` [PATCH v3 05/15] hw/arm/raspi: add a skeleton implementation of the CPRMAN Luc Michel
2020-10-10 13:57 ` [PATCH v3 06/15] hw/misc/bcm2835_cprman: add a PLL skeleton implementation Luc Michel
2020-10-10 13:57 ` [PATCH v3 07/15] hw/misc/bcm2835_cprman: implement PLLs behaviour Luc Michel
2020-10-10 13:57 ` [PATCH v3 08/15] hw/misc/bcm2835_cprman: add a PLL channel skeleton implementation Luc Michel
2020-10-10 16:05   ` Philippe Mathieu-Daudé
2020-10-17 10:00     ` Philippe Mathieu-Daudé
2020-10-10 13:57 ` [PATCH v3 09/15] hw/misc/bcm2835_cprman: implement PLL channels behaviour Luc Michel
2020-10-10 13:57 ` [PATCH v3 10/15] hw/misc/bcm2835_cprman: add a clock mux skeleton implementation Luc Michel
2020-10-10 13:57 ` [PATCH v3 11/15] hw/misc/bcm2835_cprman: implement clock mux behaviour Luc Michel
2020-10-10 15:52   ` Philippe Mathieu-Daudé
2020-10-10 13:57 ` [PATCH v3 12/15] hw/misc/bcm2835_cprman: add the DSI0HSCK multiplexer Luc Michel
2020-10-10 13:57 ` [PATCH v3 13/15] hw/misc/bcm2835_cprman: add sane reset values to the registers Luc Michel
2020-10-10 16:18   ` Philippe Mathieu-Daudé
2020-10-11 18:26     ` Luc Michel
2020-10-16 17:10       ` Philippe Mathieu-Daudé
2020-10-19 15:44         ` Philippe Mathieu-Daudé [this message]
2020-10-10 13:57 ` [PATCH v3 14/15] hw/char/pl011: add a clock input Luc Michel
2020-10-10 13:57 ` [PATCH v3 15/15] hw/arm/bcm2835_peripherals: connect the UART clock Luc Michel
2020-10-16 17:11 ` [PATCH v3 00/15] raspi: add the bcm2835 cprman clock manager Philippe Mathieu-Daudé
2020-10-19 15:45 ` Peter Maydell
2020-10-19 19:31   ` Peter Maydell
2020-10-27  8:55     ` Philippe Mathieu-Daudé
2020-10-27 11:11       ` Peter Maydell
2020-10-22 22:06 ` Philippe Mathieu-Daudé
2020-10-22 22:48   ` Guenter Roeck
2020-10-23  3:55   ` Guenter Roeck
2020-10-23 11:13     ` Philippe Mathieu-Daudé

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