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 BBB9F18871F; Sun, 9 Feb 2025 10:19:35 +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=1739096375; cv=none; b=MQweVYmw5vnkzCaAFQmlEHqrlPzXZA1TXALnNDeeO1XwMmXbx2H7lyPULz9btmbDKd+DRv5w+UtAjsiJSbAN2CqsVmbqhv+T5ptFh1Tch8TVi7ugtucOa0DUznHnOyvYPPNKcLf93ASi/jXhqwF5wqWcW5hjpZrc6IMPqTOKpZI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739096375; c=relaxed/simple; bh=UohZtJxXrZjyWBOMewDHu9Mq6/KbWKNEaqqmMlqIJr0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=So09p5ioTqi+nyi5AZeT02EoO8iCEAsk3557WKj9NyvVAVwXsO1/DHDKMgMbd3Fi73EMGhS77ZJ2UsmUl9/2WxLgw+BRCsGylzbdmrljTJkOWFh4kAUG1HRdG9c+hOzaFazn/i511k5gDq8YOANJEJuLNtlD0djHDAzuBc1/raM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TX8kVoaF; 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="TX8kVoaF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CD542C4CEE6; Sun, 9 Feb 2025 10:19:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739096375; bh=UohZtJxXrZjyWBOMewDHu9Mq6/KbWKNEaqqmMlqIJr0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=TX8kVoaF98bM1P9Fs9X1NnMeCgEqgQrXrQbWMXeUrkgn0OJHcL0wczEf4qpeXNy45 Fqp3xa8doAr3bna8kLs2du9EBvAvAIUgt7cJ/xMhj5MB4fHPlltk6V1WTCePCXmrIg r7GCtVTbTNXkQIoqpjtUG4YJrrP+i5SUvEcg0TRHsOt9PPUt0NTDeR778zGLmy46Pz HN2KjFhWFqBqKnZVNVW6XJseIkvadYbqJTu/S8jd5E9rWl2InTRUUwDPKHz7GjqGS/ WqOi7MHS/WsSAqWitngANZoEqiJdODGagwmVP3uWnq1Ou8JJkXIYQu44Xgh95wYInp yYy/5pYHY9pyA== Message-ID: <0efa70c3-dee4-4d0d-b106-d7083b5e68c3@kernel.org> Date: Sun, 9 Feb 2025 11:19:22 +0100 Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/8] dt-bindings: serial: Add support for selecting data transfer mode To: Viken Dadhaniya , neil.armstrong@linaro.org, Dmitry Baryshkov Cc: andi.shyti@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, gregkh@linuxfoundation.org, jirislaby@kernel.org, broonie@kernel.or, andersson@kernel.org, konradybcio@kernel.org, johan+linaro@kernel.org, dianders@chromium.org, agross@kernel.org, linux-arm-msm@vger.kernel.org, linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linux-spi@vger.kernel.org, quic_msavaliy@quicinc.com, quic_anupkulk@quicinc.com References: <20250124105309.295769-1-quic_vdadhani@quicinc.com> <20250124105309.295769-5-quic_vdadhani@quicinc.com> <10060d39-87a4-4565-a2a6-80c93ac2266a@kernel.org> <374e16d6-46aa-4bdf-85e9-bc2e33c38057@kernel.org> <5f710113-08b0-468e-940a-2c65e8b42486@linaro.org> <01362821-ac7f-41d7-a4c1-b1f675e9f644@quicinc.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; keydata= xsFNBFVDQq4BEAC6KeLOfFsAvFMBsrCrJ2bCalhPv5+KQF2PS2+iwZI8BpRZoV+Bd5kWvN79 cFgcqTTuNHjAvxtUG8pQgGTHAObYs6xeYJtjUH0ZX6ndJ33FJYf5V3yXqqjcZ30FgHzJCFUu JMp7PSyMPzpUXfU12yfcRYVEMQrmplNZssmYhiTeVicuOOypWugZKVLGNm0IweVCaZ/DJDIH gNbpvVwjcKYrx85m9cBVEBUGaQP6AT7qlVCkrf50v8bofSIyVa2xmubbAwwFA1oxoOusjPIE J3iadrwpFvsZjF5uHAKS+7wHLoW9hVzOnLbX6ajk5Hf8Pb1m+VH/E8bPBNNYKkfTtypTDUCj NYcd27tjnXfG+SDs/EXNUAIRefCyvaRG7oRYF3Ec+2RgQDRnmmjCjoQNbFrJvJkFHlPeHaeS BosGY+XWKydnmsfY7SSnjAzLUGAFhLd/XDVpb1Een2XucPpKvt9ORF+48gy12FA5GduRLhQU vK4tU7ojoem/G23PcowM1CwPurC8sAVsQb9KmwTGh7rVz3ks3w/zfGBy3+WmLg++C2Wct6nM Pd8/6CBVjEWqD06/RjI2AnjIq5fSEH/BIfXXfC68nMp9BZoy3So4ZsbOlBmtAPvMYX6U8VwD TNeBxJu5Ex0Izf1NV9CzC3nNaFUYOY8KfN01X5SExAoVTr09ewARAQABzSVLcnp5c3p0b2Yg S296bG93c2tpIDxrcnprQGtlcm5lbC5vcmc+wsGVBBMBCgA/AhsDBgsJCAcDAgYVCAIJCgsE FgIDAQIeAQIXgBYhBJvQfg4MUfjVlne3VBuTQ307QWKbBQJgPO8PBQkUX63hAAoJEBuTQ307 QWKbBn8P+QFxwl7pDsAKR1InemMAmuykCHl+XgC0LDqrsWhAH5TYeTVXGSyDsuZjHvj+FRP+ gZaEIYSw2Yf0e91U9HXo3RYhEwSmxUQ4Fjhc9qAwGKVPQf6YuQ5yy6pzI8brcKmHHOGrB3tP /MODPt81M1zpograAC2WTDzkICfHKj8LpXp45PylD99J9q0Y+gb04CG5/wXs+1hJy/dz0tYy iua4nCuSRbxnSHKBS5vvjosWWjWQXsRKd+zzXp6kfRHHpzJkhRwF6ArXi4XnQ+REnoTfM5Fk VmVmSQ3yFKKePEzoIriT1b2sXO0g5QXOAvFqB65LZjXG9jGJoVG6ZJrUV1MVK8vamKoVbUEe 0NlLl/tX96HLowHHoKhxEsbFzGzKiFLh7hyboTpy2whdonkDxpnv/H8wE9M3VW/fPgnL2nPe xaBLqyHxy9hA9JrZvxg3IQ61x7rtBWBUQPmEaK0azW+l3ysiNpBhISkZrsW3ZUdknWu87nh6 eTB7mR7xBcVxnomxWwJI4B0wuMwCPdgbV6YDUKCuSgRMUEiVry10xd9KLypR9Vfyn1AhROrq AubRPVeJBf9zR5UW1trJNfwVt3XmbHX50HCcHdEdCKiT9O+FiEcahIaWh9lihvO0ci0TtVGZ MCEtaCE80Q3Ma9RdHYB3uVF930jwquplFLNF+IBCn5JRzsFNBFVDXDQBEADNkrQYSREUL4D3 Gws46JEoZ9HEQOKtkrwjrzlw/tCmqVzERRPvz2Xg8n7+HRCrgqnodIYoUh5WsU84N03KlLue MNsWLJBvBaubYN4JuJIdRr4dS4oyF1/fQAQPHh8Thpiz0SAZFx6iWKB7Qrz3OrGCjTPcW6ei OMheesVS5hxietSmlin+SilmIAPZHx7n242u6kdHOh+/SyLImKn/dh9RzatVpUKbv34eP1wA GldWsRxbf3WP9pFNObSzI/Bo3kA89Xx2rO2roC+Gq4LeHvo7ptzcLcrqaHUAcZ3CgFG88CnA 6z6lBZn0WyewEcPOPdcUB2Q7D/NiUY+HDiV99rAYPJztjeTrBSTnHeSBPb+qn5ZZGQwIdUW9 YegxWKvXXHTwB5eMzo/RB6vffwqcnHDoe0q7VgzRRZJwpi6aMIXLfeWZ5Wrwaw2zldFuO4Dt 91pFzBSOIpeMtfgb/Pfe/a1WJ/GgaIRIBE+NUqckM+3zJHGmVPqJP/h2Iwv6nw8U+7Yyl6gU BLHFTg2hYnLFJI4Xjg+AX1hHFVKmvl3VBHIsBv0oDcsQWXqY+NaFahT0lRPjYtrTa1v3tem/ JoFzZ4B0p27K+qQCF2R96hVvuEyjzBmdq2esyE6zIqftdo4MOJho8uctOiWbwNNq2U9pPWmu 4vXVFBYIGmpyNPYzRm0QPwARAQABwsF8BBgBCgAmAhsMFiEEm9B+DgxR+NWWd7dUG5NDfTtB YpsFAmA872oFCRRflLYACgkQG5NDfTtBYpvScw/9GrqBrVLuJoJ52qBBKUBDo4E+5fU1bjt0 Gv0nh/hNJuecuRY6aemU6HOPNc2t8QHMSvwbSF+Vp9ZkOvrM36yUOufctoqON+wXrliEY0J4 ksR89ZILRRAold9Mh0YDqEJc1HmuxYLJ7lnbLYH1oui8bLbMBM8S2Uo9RKqV2GROLi44enVt vdrDvo+CxKj2K+d4cleCNiz5qbTxPUW/cgkwG0lJc4I4sso7l4XMDKn95c7JtNsuzqKvhEVS oic5by3fbUnuI0cemeizF4QdtX2uQxrP7RwHFBd+YUia7zCcz0//rv6FZmAxWZGy5arNl6Vm lQqNo7/Poh8WWfRS+xegBxc6hBXahpyUKphAKYkah+m+I0QToCfnGKnPqyYIMDEHCS/RfqA5 t8F+O56+oyLBAeWX7XcmyM6TGeVfb+OZVMJnZzK0s2VYAuI0Rl87FBFYgULdgqKV7R7WHzwD uZwJCLykjad45hsWcOGk3OcaAGQS6NDlfhM6O9aYNwGL6tGt/6BkRikNOs7VDEa4/HlbaSJo 7FgndGw1kWmkeL6oQh7wBvYll2buKod4qYntmNKEicoHGU+x91Gcan8mCoqhJkbqrL7+nXG2 5Q/GS5M9RFWS+nYyJh+c3OcfKqVcZQNANItt7+ULzdNJuhvTRRdC3g9hmCEuNSr+CLMdnRBY fv0= In-Reply-To: <01362821-ac7f-41d7-a4c1-b1f675e9f644@quicinc.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 09/02/2025 11:11, Viken Dadhaniya wrote: >>>>>> >>>>>> Just one blank line, but anyway, this property should not be in three >>>>>> places. Do you really expect that each of serial engines within one >>>>>> GeniQUP will be configured differently by TZ? >>>>> >>>>> Yes, each SE is configured separately and it's quite frequent when >>>>> different SEs have different DMA configuration. >>>> >>>> Well, I checked at sm8550 and sm8650 and each pair of SE - which shares >>>> resources - has the same DMAs, so I would not call it frequent. Care to >>>> bring an example where same serial engines have different DMAs and >>>> different TZ? We do not talk about single QUP. >>> >>> Well, I don't have access to the latest sm8550 / sm8650 devcfg sources. >>> I checked the RB5 ones. As far as I understand out of 14 enabled SEs >>> only two are configured for the GSI DMA, others should use FIFO / SE >>> DMA. Same applies to the SM8250 MTP devices. Checking the RB1 / RB2 >>> setup also shows 3 out of 6 SEs being set for GSI. >> >> I think selecting GSI DMA is only for devices needs high speed streaming >> to the >> device, like the touch screen, using GSI DMA for random small access is >> a non-sense. >> >> But the thing is, in the TZ world the configuration was static so we had >> no choice >> of using GSI DMA when configured, but now we have the choice so we could >> totally >> reconfigure the SE with the transfer type (FIFO, SE DMA or GSI DMA) as >> runtime and >> drop this attribute. >> >> So instead of hardcoding this, add a way to dynamically select either of >> the 3 >> transfer types when firmware can be loaded from HLOS. >> >> Neil >> > > Yes, GSI DMA mode is required for specific use cases only. > > Dynamically switching from GSI mode to non-GSI mode is neither possible > nor useful. For each SE, the use case is fixed, and based on the use > case, the developer can choose the mode via the device tree property. No, it cannot. Do not describe downstream as something set in stone. Best regards, Krzysztof