From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC3D053E22; Fri, 28 Jun 2024 06:21:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719555675; cv=none; b=W2BnYHmG5ihV1vLKG+qghgHvTb2OoEnXM5L4R6tO0womr/06HSEorKJlEsvmQtdEsKfZlXsPUwK7ZDBi9HHMdZ6nTT/GhOHZ8H4rQ1LTFWD/N6sFcVvDUbP5TT2EZ8nKzebG81+MzP7+acqKuoFR5sA1C4uqD5TmCvhouZZNaXo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719555675; c=relaxed/simple; bh=yBTv5tI3Sw2vpf33F6ktr6RkDe8svdLFayCCcurDMy4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=RQ/f+zGBsmQti0+a7vj/KASJiTu4Q3dL4WtEKWTu2+CijtrV+bTwXQsBE0z1Twm2sksQIZgmvY9eMs/LzXBJvOPaNpJT7ukmie4ywSKMUTi/R6plBAAYXwX1zz2Lk9JQLSMxKnVUDOfhV52mxPlno+AqlTUqrZbAZUbtpX0mAnU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=G58EjGeC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="G58EjGeC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E656C116B1; Fri, 28 Jun 2024 06:21:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719555675; bh=yBTv5tI3Sw2vpf33F6ktr6RkDe8svdLFayCCcurDMy4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=G58EjGeCjrdn8DXizeITnU9RyPa05/QjdYaCK1GiuLKUqD5ohnOn8HSvQFFmzA5D6 qA/CmX5SJN5v3kOJFMH5EbPvAxOAx5LP7SISO/RKJxxNfwbHl6BtOlsdUmFa9z1/0O wXZJkSYU6MO6/dKroxDHTyLb/xvd9A7kP+YRCszTsevJWgnzzLOJNuFteiCtRS8Qup mhP0HMbvyo5RsPE/EeCt9qpwtq86Z9AOluvvsm3ttWC5Q4q7aYmTf51UxP/73ePpXr wb593U6nOalNTX38NmOPoeRLpNTKzovNVO+LXBF8L//zM+//PWOay0mx/RHPfmbGpv D4nmqERmet7cg== Message-ID: <79955001-132c-4eef-b741-9e6a35da1361@kernel.org> Date: Fri, 28 Jun 2024 08:21:05 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] clk: imx93: Drop macro IMX93_CLK_END To: Peng Fan , Pengfei Li Cc: "krzk+dt@kernel.org" , "robh@kernel.org" , "abelvesa@kernel.org" , "mturquette@baylibre.com" , "sboyd@kernel.org" , "conor+dt@kernel.org" , "shawnguo@kernel.org" , "s.hauer@pengutronix.de" , Jacky Bai , Ye Li , Aisheng Dong , Frank Li , "kernel@pengutronix.de" , "festevam@gmail.com" , "linux-clk@vger.kernel.org" , "imx@lists.linux.dev" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" References: <20240625175147.94985-1-pengfei.li_1@nxp.com> <20240625175147.94985-2-pengfei.li_1@nxp.com> <39bcab8b-ed9c-4da9-b1ee-32dbfb2a23a4@kernel.org> <61c1eb8b-b8fd-4e9e-b0fc-27ce1c2eb2b1@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 28/06/2024 03:17, Peng Fan wrote: >> Subject: Re: [PATCH 1/2] clk: imx93: Drop macro IMX93_CLK_END >> >> On 25/06/2024 12:43, Pengfei Li wrote: >>> On Tue, Jun 25, 2024 at 09:44:42AM +0200, Krzysztof Kozlowski >> wrote: >>>> On 25/06/2024 19:51, Pengfei Li wrote: >>>>> IMX93_CLK_END was previously defined in imx93-clock.h to >> indicate >>>>> the number of clocks, but it is not part of the ABI, so it should be >>>>> dropped. >>>>> >>>>> Now, the driver gets the number of clks by querying the maximum >>>>> index in the clk array. Due to the discontinuity in the definition >>>>> of clk index, with some gaps present, the total count cannot be >>>>> obtained by summing the array size. >>>>> >>>>> Signed-off-by: Pengfei Li >>>>> --- >>>>> drivers/clk/imx/clk-imx93.c | 25 +++++++++++++++++++++---- >>>>> 1 file changed, 21 insertions(+), 4 deletions(-) >>>>> >>>>> diff --git a/drivers/clk/imx/clk-imx93.c >>>>> b/drivers/clk/imx/clk-imx93.c index c6a9bc8ecc1f..68c929512e16 >>>>> 100644 >>>>> --- a/drivers/clk/imx/clk-imx93.c >>>>> +++ b/drivers/clk/imx/clk-imx93.c >>>>> @@ -257,6 +257,20 @@ static const struct imx93_clk_ccgr >> { static >>>>> struct clk_hw_onecell_data *clk_hw_data; static struct clk_hw >>>>> **clks; >>>>> >>>>> +static int imx_clks_get_num(void) >>>>> +{ >>>>> + u32 val = 0; >>>>> + int i; >>>>> + >>>>> + for (i = 0; i < ARRAY_SIZE(root_array); i++) >>>>> + val = max_t(u32, val, root_array[i].clk); >>>>> + >>>>> + for (i = 0; i < ARRAY_SIZE(ccgr_array); i++) >>>>> + val = max_t(u32, val, ccgr_array[i].clk); >>>>> + >>>>> + return val + 1; >>>>> +} >>>>> + >>>>> static int imx93_clocks_probe(struct platform_device *pdev) { >>>>> struct device *dev = &pdev->dev; >>>>> @@ -264,14 +278,17 @@ static int imx93_clocks_probe(struct >> platform_device *pdev) >>>>> const struct imx93_clk_root *root; >>>>> const struct imx93_clk_ccgr *ccgr; >>>>> void __iomem *base, *anatop_base; >>>>> + int clks_num; >>>>> int i, ret; >>>>> >>>>> + clks_num = imx_clks_get_num(); >>>>> + >>>>> clk_hw_data = devm_kzalloc(dev, struct_size(clk_hw_data, >> hws, >>>>> - IMX93_CLK_END), >> GFP_KERNEL); >>>>> + clks_num), GFP_KERNEL); >>>>> if (!clk_hw_data) >>>>> return -ENOMEM; >>>>> >>>>> - clk_hw_data->num = IMX93_CLK_END; >>>>> + clk_hw_data->num = clks_num; >>>> >>>> Why so complicated code instead of pre-processor define or array >> size? >>>> >>>> Best regards, >>>> Krzysztof >>>> >>>> >>> >>> Hi Krzysztof, >>> >>> Thanks for the comment, here are some of our thoughts. >>> >>> Regarding the predefined method, it's easy to forget to update the >>> macro definition when adding some new clocks to imx93-clock.h in >> the future. >> >> Somehow most developers in most platforms can do it... Anyway, that >> would be build time detectable so no problem at all. >> >>> >>> Also, we cannot use the array size method in this scenario, as some >>> unnecessary clocks have been removed in the past, resulting in >>> discontinuous definitions of clock indexes. This means that the >>> maximum clock index can be larger than the allocated clk_hw array >> size. At this point, using the maximum index to access the clk_hw array >> will result in an out of bounds error. >> >> You mix bindings with array entries. That's independent or just clock >> drivers are broken. > > But there is issue that binding update and clock driver are normally in > two patches. So if just use the IMX93_CLK_END in this file, > it will be easy to break `git bisect`. There is no issue. Srsly, this would be the only, only one driver having that issue. How is this even possible? How adding one new define for pre-processor would cause driver issues or some sort of bisectability problems? These are basics of C we talk about now... Best regards, Krzysztof