Re: [RFC v3 05/18] pmdomain: thead: Add power-domain driver for TH1520

Krzysztof Kozlowski
2025-01-22T07:47:19Z

On 21/01/2025 22:42, Michal Wilczynski wrote:
>
>
> On 1/21/25 11:02, Krzysztof Kozlowski wrote:
>> On Mon, Jan 20, 2025 at 06:20:58PM +0100, Michal Wilczynski wrote:
>>> The T-Head TH1520 SoC contains multiple power islands that can be
>>> programmatically turned on and off using the AON (Always-On) protocol
>>> and a hardware mailbox [1]. The relevant mailbox driver has already been
>>> merged into the mainline kernel in commit 5d4d263e1c6b ("mailbox:
>>> Introduce support for T-head TH1520 Mailbox driver");
>>>
>>> This commit introduces a power-domain driver for the TH1520 SoC, which
>>
>> Please do not use "This commit/patch/change", but imperative mood. See
>> longer explanation here:
>> https://protect2.fireeye.com/v1/url?k=2123f702-40a8e22d-21227c4d-74fe485cbfe7-afb876722bdc8fc5&q=1&e=e5dabc89-5f0c-4819-9008-76faafc3c1bc&u=https%3A%2F%2Felixir.bootlin.com%2Flinux%2Fv5.17.1%2Fsource%2FDocumentation%2Fprocess%2Fsubmitting-patches.rst%23L95
>>
>>> is using AON firmware protocol to communicate with E902 core through the
>>> hardware mailbox. This way it can send power on/off commands to the E902
>>> core.
>>
>> ...
>>
>>> diff --git a/drivers/pmdomain/thead/Makefile b/drivers/pmdomain/thead/Makefile
>>> new file mode 100644
>>> index 000000000000..adfdf5479c68
>>> --- /dev/null
>>> +++ b/drivers/pmdomain/thead/Makefile
>>> @@ -0,0 +1,2 @@
>>> +# SPDX-License-Identifier: GPL-2.0-only
>>> +obj-$(CONFIG_TH1520_PM_DOMAINS) += th1520-pm-domains.o
>>> diff --git a/drivers/pmdomain/thead/th1520-pm-domains.c b/drivers/pmdomain/thead/th1520-pm-domains.c
>>> new file mode 100644
>>> index 000000000000..d913ad40fb76
>>> --- /dev/null
>>> +++ b/drivers/pmdomain/thead/th1520-pm-domains.c
>>> @@ -0,0 +1,174 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Copyright (C) 2021 Alibaba Group Holding Limited.
>>> + * Copyright (c) 2024 Samsung Electronics Co., Ltd.
>>> + * Author: Michal Wilczynski <m.wilczynski@samsung.com>
>>> + */
>>> +
>>> +#include <linux/firmware/thead/thead,th1520-aon.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/pm_domain.h>
>>> +
>>> +#include <dt-bindings/firmware/thead,th1520-aon.h>
>>
>> So here it is used... I don't understand why power domain is under
>> firmware. Please move it to proper directory and name the file exactly
>> the same as bindings doc which this belongs to.
>
> The power-domain driver has no bindings doc. It's a child driver of the AON
> node.

OK, not changing my comment, though.

>
>>
>>
>>> +
>>> +struct th1520_power_domain {
>>> + struct th1520_aon_chan *aon_chan;
>>> + struct generic_pm_domain genpd;
>>> + u32 rsrc;
>>> +};
>>> +
>>> +struct th1520_power_info {
>>> + const char *name;
>>> + u32 rsrc;
>>> +};
>>> +
>>> +static const struct th1520_power_info th1520_pd_ranges[] = {
>>> + { "vdec", TH1520_AON_VDEC_PD },
>>
>> Why TH1520_AON_XXX aren't the indices?
>
> These power-domain constants are defined by the AON firmware protocol,
> which dictates the exact IDs (e.g., 1 for NPU). They are not just array
> indices; we must use these specific values to communicate with the
> firmware correctly. Using array indices starting with 1 would be
> unusual.

Then that's a no. Binding constants do not represent values used by your
hardware. The binding constant should start from 0.

Best regards,
Krzysztof