From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6CD79C5DF85 for ; Thu, 20 Aug 2026 17:18:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=FLRTZnEDviijJzsjwddfvnyaqLbr2r1IukiSisfKzmc=; b=Z2d8tjZeFubaxU+o+T3q9NR7mR 1VPnRFSb34M+d1JduCyD8XbET+iJliCbDMjroakk62AjcJrJqayGEuW5GmLZRazcsmEWAfM99QUcp /5dtCpQILDaLp0AGwqbjt6nSeZf3qza6LJVSoTzflk97lwg36w3Ba7qh2IVWbSMai/jDjaN//UZfS xwx1MROlT0hihEDLydpj4fjWYu5H4s7+Oh0L1x5CMwtMBOV1pnWfkDVHJwewrIqRMZ8tm4By3Rton qnIhH5K4p6PpYOIgVxTqeG1HPj88Qg+pCB9SK41RO0zQ463E88TPTsTVjWW1GCdK+CTEJqgI67gdN q7LNiO7g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wx6Pn-0000000Bx8u-18XY; Thu, 20 Aug 2026 17:18:55 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wx6Pl-0000000Bx8L-3qgf; Thu, 20 Aug 2026 17:18:53 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 0E8A460A73; Thu, 20 Aug 2026 17:18:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 89BC51F00A3F; Thu, 20 Aug 2026 17:18:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787246332; bh=FLRTZnEDviijJzsjwddfvnyaqLbr2r1IukiSisfKzmc=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=eXpT+79Qr29I+auqIZyO6vPcyQMnyFicpz48SJ+z3e7S62QUWBZWfa+LNNUa2rmA2 Xyg0hWrYhs69ufEsGeCVW9YqyhoiwnfMf78sorTgRlDBULOrVBzgTZiMfumT4c1CJ7 c6Hu+go7sDDSNJv/b5w9sRXhvKTirixYauikD5ERsOGP3i2G0/arzYhiNH/7KROA2h v5LrTOZy/S4Dzmnoq6HQ+tWC7nta/eNNVI1Gn7vr9u9NDUduh0oZac7UW0OaT96EDs DnO3Onw2mYB2MwISBLiY3VCSbjr/PwhsYbAkSob8F71uS9Aw5Y+6PpiwPl2YHsJZvE WVqk2MEMYpTag== Date: Thu, 20 Aug 2026 10:18:51 -0700 From: Jakub Kicinski To: Daniel Pawlik Cc: netdev@vger.kernel.org, lorenzo@kernel.org, win847@gmail.com, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Subject: Re: [PATCH v8] net: airoha: npu: use cacheline-sized buffers for mailbox DMA Message-ID: <20260820101851.0b4c284a@kernel.org> In-Reply-To: References: <20260817090601.1256389-1-pawlik.dan@gmail.com> <20260817161756.5fd2185a@kernel.org> <20260818082933.28b5c9d1@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Thu, 20 Aug 2026 10:20:08 +0200 Daniel Pawlik wrote: > size=24 < cache_line=64 fails this regardless of address alignment. > The swiotlb sync code itself is fine, but the NPU cannot DMA-write to > the bounce buffer address range (it reads commands fine, never writes > responses back). This is probably an EN7581 platform limitation. Sure, that's pretty much what GPT told us some revisions ago. The question is why.