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

Michal Wilczynski
2025-01-21T21:42:20Z

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.

>
>
>> +
>> +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.

>
>> + { "npu", TH1520_AON_NPU_PD },
>> + { "venc", TH1520_AON_VENC_PD },
>> + { "gpu", TH1520_AON_GPU_PD },
>> + { "dsp0", TH1520_AON_DSP0_PD },
>> + { "dsp1", TH1520_AON_DSP1_PD }
>> +};
>
> Best regards,
> Krzysztof