From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f53.google.com (mail-wr1-f53.google.com [209.85.221.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8307A46B91; Wed, 24 Jul 2024 07:46:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721807163; cv=none; b=Ey5Jkhkz1DEeDqOmHb7zbaWW1LVSo1UCF/q+jD72M/afldBERbX5mgOoeevJsKc/MDB9qx8+11TmVQ1EPu0xctvHzWLPjbW3AWF0GtvDXSBHISBtTc1/8UMyr6BLwVT3+GWu+KO1sg50o4XGx9O2+Xm5OnETbuItjTnQPYd5Uxc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721807163; c=relaxed/simple; bh=8KoCmA+JnWG5GHt2isUS1L2Eg0/e4RGYIyMCqa/2anU=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=VyMh50oUk/56AceQsIcANAEXWkqFYPNzzznb/13OpIsEkCUX13R4kF1GmtGGKkdK7wdLxWJxG3YptNrFY6MnlZtgAis71RUGe9dtPqDr5YgOzdH19mE5W6gLhXuRIxeAI6ScNbakAhpLIdBOmEkvXkyp6M4292Z4PTThP2uABU0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Hb4BYxFc; arc=none smtp.client-ip=209.85.221.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Hb4BYxFc" Received: by mail-wr1-f53.google.com with SMTP id ffacd0b85a97d-368380828d6so3545190f8f.1; Wed, 24 Jul 2024 00:46:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1721807160; x=1722411960; darn=vger.kernel.org; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:from:to:cc:subject :date:message-id:reply-to; bh=8KoCmA+JnWG5GHt2isUS1L2Eg0/e4RGYIyMCqa/2anU=; b=Hb4BYxFc8doCo2xmIEs8QsXR5u8CVdZ3by27QOpoqpFaxDBT3PQ2ArqIIQ/Bnh2UVI W7SVpaVWY4fJ31PP9F9L1WBB6moS7+zZ9fbzm66+RsNLt3sgJrFu1Cj6vSCIdn4WikF6 mi7sDfyvHRmb4N2w4lTCrVQCJwnOolty8Ru6zLf4aDyaI8jMXDjXD3q6rTysIII4fYut Kw/VWaUah+PaBNvFu6OukgI0tcjs+wc+lyJbM99317Xl4v7LQaPGkYwFGbdWLKqLW5Ze OhejHgeV58cReEjRUTf9V2FLDiZupps6qkkZdvmMQntDRZwoY4OmsEjLA8go70YTRtEA oKTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1721807160; x=1722411960; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=8KoCmA+JnWG5GHt2isUS1L2Eg0/e4RGYIyMCqa/2anU=; b=fxbNtz25IjsBFDMWOiaWkBTnXxVaKmtTEu+P6XMiFyDPVyErafJjIAZXPhaN5zy3T3 cWOGrjpPLnAzuDvAIPSFhbAmhET+mp41iOlgPh3p3MRG5N9qa1lD1TOhVwim3+QSqMAv KWIq7yJZsQiyEARMjmoFiGXhcEYvP44exEV7oL9P8LS1/Vbg5oOkaSGrfpCsxPosanBE ZtMg5WbPgNWJP4RhiLunFVC1QfUcMwLRsn9gAF8GYz58TftbpBEEc/oNrcAea2leyHry yxOv4mByZPjROBS4XIwzx5BMcv5r1WES9DfmqqRXPlA4+rkYoCqSbbUp/AgLbMwIRd8w 38rw== X-Forwarded-Encrypted: i=1; AJvYcCXZuUAJ5vcZGsX8gQ2//xzd272D7z5Ax1T42PV50UDDLyhkuR9RT8kuhx7qaInw8QONJ7c27JC+/Ghe9x1O3oGozK+YCKGAkhyGCLV7elun67ZDXwSMJJoQuFXbn0/xc/vRG2ylbf6I X-Gm-Message-State: AOJu0YzpyGupoUWdxe2GmqR6BLChUuDtUR1I2KbF0WBerUdZi5+kq6Rt +J7ASFqxGuNl7hM5jKQ8492NE3xexZz2P0WfLEDlUZFEAsja3xZJ X-Google-Smtp-Source: AGHT+IHO2VhjrBItnZjQ1/CCPoY+qcfvnVMk/WY2GxYprSVed+mvtBH9RtHoJJVCcb7QgvOwoKhWQw== X-Received: by 2002:adf:fc0c:0:b0:368:714e:5a5e with SMTP id ffacd0b85a97d-369debf8bbbmr4277080f8f.2.1721807159640; Wed, 24 Jul 2024 00:45:59 -0700 (PDT) Received: from nsa.fritz.box ([2001:a61:359b:e801:d44:32b3:6924:10d1]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-368787eb6b0sm13535315f8f.90.2024.07.24.00.45.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Jul 2024 00:45:59 -0700 (PDT) Message-ID: <05203de8fde109255b6e99a08e57037525a629ea.camel@gmail.com> Subject: Re: [PATCH] spi: axi-spi-engine: don't emit XFER_BITS for empty xfer From: Nuno =?ISO-8859-1?Q?S=E1?= To: David Lechner , Mark Brown Cc: Michael Hennerich , Nuno =?ISO-8859-1?Q?S=E1?= , linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 24 Jul 2024 09:45:59 +0200 In-Reply-To: <20240723-spi-axi-spi-engine-opt-bpw-v1-1-2625ba4c4387@baylibre.com> References: <20240723-spi-axi-spi-engine-opt-bpw-v1-1-2625ba4c4387@baylibre.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.52.2 (3.52.2-1.fc40) Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2024-07-23 at 13:36 -0500, David Lechner wrote: > This adds a check on xfer->len to avoid emitting an XFER_BITS > instruction for empty transfers in the AXI SPI Engine driver. This > avoids unnecessary delays caused by executing an instruction that has > no effect on the actual SPI transfer. >=20 > Signed-off-by: David Lechner > --- Reviewed-by: Nuno Sa