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 E04391E50B; Fri, 20 Sep 2024 12:36:42 +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=1726835803; cv=none; b=jDT/EwWQ/tzyf9sTSBKbPnkD5eAQqIRWYG9onQD0uXmkYvyiAgCEztIfkvQ2dENf3RI+y0WPkdq8MByrEMvUHHjTI9y6sKx/LtlEpBx2M1V2uhbow/srAKNE9Jh11krGNOgUUXBrQA6JjU5NL8D+UW8zJYxUJKTtxgBGb2RLRIU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726835803; c=relaxed/simple; bh=sX+koPWYyb+HTqwuKE13tVkzTG40JdkQAM3ue8rQglA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=F61mX90YUueZOhYKHZuNmh5CxfcHecBTT5jyvz2mTJdAC4AH+ISzDO7jaYUhc6gvZMajqMDM+Nv8oJMORp8IKkVnLw+Jo0wMxQNRAY5s6OdmPwLOqueoxudN5VvUnDuo7txew2JY14aTOhfs3SloYr8eB7BhfShdC5jtM/COCK0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=i8ONaiyr; 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="i8ONaiyr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F3A9C4CEC3; Fri, 20 Sep 2024 12:36:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726835802; bh=sX+koPWYyb+HTqwuKE13tVkzTG40JdkQAM3ue8rQglA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=i8ONaiyrkkfQtVxEJVVQNoAHSJkbJ9ZKCr+RPWPGlNzL7jsKMoY/v1NdqMnOvY+Um lxC8vTsLc9Guq1RH2cxfKfGRfeUvV+Ifd4daK+eVrlX2xybCQk6EKSG530bmaFgSRF x6bpWfRbUcXME2bqVJf95P+Crx2sQNjYCgWm3CXoFXJBYOaMFx7WPnUGYQsTkDCPEC 5hWqXD6rRwLan4Ds4pPrThkYJU0NiTOXKPI8bERv5TsZUIpcuen4mIXrIWaDp1stBk BnjlzIQcKmPvEGKw7848BUtG8VSVKn2eMv2SyLAnDJdE56KbWN/WN2F+XF5BjkZyx7 ij9q3AJut3uAw== Message-ID: <1c6c56f7-bdda-4e14-9910-80e0cda0d631@kernel.org> Date: Fri, 20 Sep 2024 14:36:37 +0200 Precedence: bulk X-Mailing-List: linux-clk@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] clk: samsung: fsd: Mark PLL_CAM_CSI as critical To: Inbaraj E , 'Stephen Boyd' , alim.akhtar@samsung.com, cw00.choi@samsung.com, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org, mturquette@baylibre.com, s.nawrocki@samsung.com Cc: pankaj.dubey@samsung.com, gost.dev@samsung.com References: <20240917101016.23238-1-inbaraj.e@samsung.com> <0d43a00985a815c1869ebc6c441a2aed.sboyd@kernel.org> <00f001db0a87$cd9ddfa0$68d99ee0$@samsung.com> <633ff284-101d-4651-833e-a6b01626c9a1@kernel.org> <011401db0b13$cbd045f0$6370d1d0$@samsung.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 20/09/2024 06:15, Inbaraj E wrote: > > >> -----Original Message----- >> From: Inbaraj E >> Sent: 20 September 2024 09:35 >> To: 'Krzysztof Kozlowski' ; 'Stephen Boyd' >> ; 'alim.akhtar@samsung.com' >> ; 'cw00.choi@samsung.com' >> ; 'linux-clk@vger.kernel.org' > clk@vger.kernel.org>; 'linux-kernel@vger.kernel.org' > kernel@vger.kernel.org>; 'linux-samsung-soc@vger.kernel.org' > samsung-soc@vger.kernel.org>; 'mturquette@baylibre.com' >> ; 's.nawrocki@samsung.com' >> >> Cc: 'pankaj.dubey@samsung.com' ; >> 'gost.dev@samsung.com' >> Subject: RE: [PATCH] clk: samsung: fsd: Mark PLL_CAM_CSI as critical >> >> >> >>> -----Original Message----- >>> From: Krzysztof Kozlowski >>> Sent: 19 September 2024 17:33 >>> To: Inbaraj E ; 'Stephen Boyd' >>> ; alim.akhtar@samsung.com; >> cw00.choi@samsung.com; >>> linux-clk@vger.kernel.org; linux-kernel@vger.kernel.org; >>> linux-samsung- soc@vger.kernel.org; mturquette@baylibre.com; >>> s.nawrocki@samsung.com >>> Cc: pankaj.dubey@samsung.com; gost.dev@samsung.com >>> Subject: Re: [PATCH] clk: samsung: fsd: Mark PLL_CAM_CSI as critical >>> >>> On 19/09/2024 13:33, Inbaraj E wrote: >>>> >>>> >>>>> -----Original Message----- >>>>> From: Stephen Boyd >>>>> Sent: 19 September 2024 15:51 >>>>> To: Inbaraj E ; alim.akhtar@samsung.com; >>>>> cw00.choi@samsung.com; krzk@kernel.org; linux-clk@vger.kernel.org; >>>>> linux- kernel@vger.kernel.org; linux-samsung-soc@vger.kernel.org; >>>>> mturquette@baylibre.com; s.nawrocki@samsung.com >>>>> Cc: pankaj.dubey@samsung.com; gost.dev@samsung.com; Inbaraj E >>>>> >>>>> Subject: Re: [PATCH] clk: samsung: fsd: Mark PLL_CAM_CSI as >>>>> critical >>>>> >>>>> Quoting Inbaraj E (2024-09-17 03:10:16) >>>>>> PLL_CAM_CSI is the parent clock for the ACLK and PCLK in the >>>>>> CMU_CAM_CSI block. When we gate ACLK or PCLK, the clock >> framework >>>>> will >>>>>> subsequently disables the parent clocks(PLL_CAM_CSI). Disabling >>>>>> PLL_CAM_CSI is causing sytem level halt. >>>>>> >>>>>> It was observed on FSD SoC, when we gate the ACLK and PCLK during >>>>>> CSI stop streaming through pm_runtime_put system is getting halted. >>>>>> So marking PLL_CAM_CSI as critical to prevent disabling. >>>>>> >>>>>> Signed-off-by: Inbaraj E >>>>>> --- >>>>> >>>>> Please add a fixes tag. Although this is likely a band-aid fix >>>>> because marking something critical leaves it enabled forever. >>>> >>>> Sure, will add fixes tag. As per HW manual, this PLL_CAM_CSI is >>>> supplying clock even for CMU SFR access of CSI block, so we can't >>>> gate this. >>> >>> Hm, I am not so sure. The CMU driver should just take appropriate clock. >>> Sprinkling CLK_CRITICAL looks as substitute of missing clock handling/ >> >> As per HW design, PLL_CAM_CSI is responsible for suppling clock to CSI SFR, >> CMU SFR and some internal block of CAM_CSI. In this some of the clock is not >> handled by any driver but it is required for CSI to work properly. For example >> CSI NOC clock. So this is the reason we are marking PLL_CAM_CSI as critical. >> > > This is clock hierarchy for CMU_CAM_CSI block. > > PLL_CAM_CSI -----> DIVIDER --------> CSI_SFR clock > | > |----> DIVIDER --------> CMU_SFR clock > | > |----> DIVIDER --------> CSI NOC clock. > And what is the problem in adding proper handling in the driver? You just described case valid for 99% of SoC components. Best regards, Krzysztof