From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
To: Nathan Chancellor <nathan@kernel.org>
Cc: djakov@kernel.org, robh@kernel.org,
krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
matthias.bgg@gmail.com, lgirdwood@gmail.com, broonie@kernel.org,
keescook@chromium.org, gustavoars@kernel.org,
henryc.chen@mediatek.com, linux-pm@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, kernel@collabora.com,
wenst@chromium.org, amergnat@baylibre.com,
Dawei Chien <dawei.chien@mediatek.com>
Subject: Re: [PATCH v5 4/7] soc: mediatek: Add MediaTek DVFS Resource Collector (DVFSRC) driver
Date: Mon, 29 Apr 2024 10:08:20 +0200 [thread overview]
Message-ID: <57529d24-8b46-4eed-95ed-463ad3f4190e@collabora.com> (raw)
In-Reply-To: <20240424190405.GA2803128@dev-arch.thelio-3990X>
Il 24/04/24 21:04, Nathan Chancellor ha scritto:
> Hi Angelo,
>
> On Wed, Apr 24, 2024 at 11:54:13AM +0200, AngeloGioacchino Del Regno wrote:
>> The Dynamic Voltage and Frequency Scaling Resource Collector (DVFSRC) is a
>> Hardware module used to collect all the requests from both software and the
>> various remote processors embedded into the SoC and decide about a minimum
>> operating voltage and a minimum DRAM frequency to fulfill those requests in
>> an effort to provide the best achievable performance per watt.
>>
>> This hardware IP is capable of transparently performing direct register R/W
>> on all of the DVFSRC-controlled regulators and SoC bandwidth knobs.
>>
>> This driver includes support for MT8183, MT8192 and MT8195.
>>
>> Co-Developed-by: Dawei Chien <dawei.chien@mediatek.com>
>> [Angelo: Partial refactoring and cleanups]
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ...
>> drivers/soc/mediatek/mtk-dvfsrc.c | 551 +++++++++++++++++++++++
> ...
>> +#define KBPS_TO_MBPS(x) ((x) / 1000)
> ...
>> +static void __dvfsrc_set_dram_bw_v1(struct mtk_dvfsrc *dvfsrc, u32 reg,
>> + u16 max_bw, u16 min_bw, u64 bw)
>> +{
>> + u32 new_bw = (u32)div_u64(KBPS_TO_MBPS(bw), 100);
>> +
>> + /* If bw constraints (in mbps) are defined make sure to respect them */
>> + if (max_bw)
>> + new_bw = min(new_bw, max_bw);
>> + if (min_bw && new_bw > 0)
>> + new_bw = max(new_bw, min_bw);
>> +
>> + dvfsrc_writel(dvfsrc, reg, new_bw);
>> +}
>
> Using KBPS_TO_MBPS here results in
>
> ERROR: modpost: "__aeabi_uldivmod" [drivers/soc/mediatek/mtk-dvfsrc.ko] undefined!
>
> when building ARCH=arm allmodconfig with clang. I did not check to see
> if this is visible with GCC but if it is not, it is only because GCC
> implements certain transformations for constant division that clang may
> or may not have implemented (there was some work on getting all
> transformations that GCC has supported in clang as well but I do not
> think was ever completed). Perhaps KBPS_TO_MBPS() should be dropped and
> the new_bw assignement turned into
>
> u32 new_bw = (u32)div_u64(bw, 100 * 1000); /* Multiply divisor by 1000 to convert bw from Kbps to Mbps */
Thanks, I honestly didn't check clang.
Your suggestion looks good, I'll do exactly that.
Cheers!
Angelo
>
> or something like that.
>
> Cheers,
> Nathan
next prev parent reply other threads:[~2024-04-29 8:08 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-24 9:54 [PATCH v5 0/7] MediaTek DVFSRC Bus Bandwidth and Regulator knobs AngeloGioacchino Del Regno
2024-04-24 9:54 ` [PATCH v5 1/7] dt-bindings: regulator: Add bindings for MediaTek DVFSRC Regulators AngeloGioacchino Del Regno
2024-04-24 9:54 ` [PATCH v5 2/7] dt-bindings: interconnect: Add MediaTek EMI Interconnect bindings AngeloGioacchino Del Regno
2024-04-24 9:54 ` [PATCH v5 3/7] dt-bindings: soc: mediatek: Add DVFSRC bindings for MT8183 and MT8195 AngeloGioacchino Del Regno
2024-04-24 9:54 ` [PATCH v5 4/7] soc: mediatek: Add MediaTek DVFS Resource Collector (DVFSRC) driver AngeloGioacchino Del Regno
2024-04-24 19:04 ` Nathan Chancellor
2024-04-29 8:08 ` AngeloGioacchino Del Regno [this message]
2024-04-29 14:13 ` Georgi Djakov
2024-04-24 9:54 ` [PATCH v5 5/7] regulator: Remove mtk-dvfsrc-regulator.c AngeloGioacchino Del Regno
2024-04-24 9:54 ` [PATCH v5 6/7] regulator: Add refactored mtk-dvfsrc-regulator driver AngeloGioacchino Del Regno
2024-04-24 10:35 ` Christophe JAILLET
2024-04-24 12:53 ` AngeloGioacchino Del Regno
2024-04-24 12:54 ` AngeloGioacchino Del Regno
2024-04-24 9:54 ` [PATCH v5 7/7] interconnect: mediatek: Add MediaTek MT8183/8195 EMI Interconnect driver AngeloGioacchino Del Regno
2024-05-03 11:53 ` Georgi Djakov
2024-05-06 10:49 ` AngeloGioacchino Del Regno
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