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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D30EC433ED for ; Thu, 13 May 2021 02:09:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 475AE61417 for ; Thu, 13 May 2021 02:09:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230175AbhEMCKP (ORCPT ); Wed, 12 May 2021 22:10:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:55888 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229630AbhEMCKO (ORCPT ); Wed, 12 May 2021 22:10:14 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 04F0660FE9; Thu, 13 May 2021 02:09:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620871745; bh=VGw1fMdv7a1LyI1pnnicV4IuFjxiNwdg/mYbWWDFhHA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Cra+afcn4f04+Ui4+XAyl1MzvES37KAqkJocA6GKzLJcNHurLa02CD7gEnj0JR0X6 v/o1/o3oukhhXGJIB0d4ggspmzvuoututtLhbjI2Y3g4OF3I42uw5LA0NDtL4AJcBb ECh1W5NDfGGu64DXkDsXrTjr7YUg+yGvkirWZK9MtNwcb1XtAOhX6LKQ9KNZ0GvQXf asMbA5yOQPeWUJZp2najeUon31au7gPkA/abtobbb7Nu1gKKTVjOpttt0OyOoGc5I8 XD1GXTizzHkxkRJtOa7/Mt7nlh3iQkAPlQeQU/puVMYF6+fCuogGehC0ENouoKj3hO VVLPaSw983b7w== Date: Thu, 13 May 2021 10:09:00 +0800 From: Shawn Guo To: Adam Ford Cc: Robin Gong , arm-soc , Rob Herring , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , dl-linux-imx , devicetree , Linux Kernel Mailing List Subject: Re: [PATCH 1/2] arm64: dts: imx8mn: Add spba1 bus Message-ID: <20210513020859.GI3425@dragon> References: <20210406013344.124255-1-aford173@gmail.com> <20210511024604.GE3425@dragon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, May 11, 2021 at 09:48:38AM -0500, Adam Ford wrote: > On Tue, May 11, 2021 at 7:20 AM Robin Gong wrote: > > > > On 2021/05/11 18:45 Adam Ford wrote: > > > > Also may I ask if you have a real use case for this bus node? > > > > > > The reference manual shows the SPBA bus tells the DMA controller which > > > peripherals are associated with it. Nearly all the i.MX boards use this. The > > > boards I support have Bluetooth devices connected to a UART running high > > > speeds, and if the DMA driver isn't loaded, I can see a performance change. > > Compare PIO with DMA on UART, but not w/o this 'spba bus node ' patch? > > > > > In fact, if the DMA firmware isn't loaded, I often get transfer errors. > > UART use SDMA ROM firmware instead of RAM firmware, so it should work > > even without sdma RAM firmware loaded. Still curious what really happen in > > your board without this patch. > > What I am seeing is that at times, the HCI UART loading before the DMA > firmware is loaded. > > [ 10.582037] Bluetooth: HCI UART driver ver 2.3 > [ 10.586867] Bluetooth: HCI UART protocol H4 registered > [ 10.593566] imx-sdma 30bd0000.dma-controller: sdma firmware not ready! > [ 10.594548] Bluetooth: HCI UART protocol Broadcom registered > [ 10.600108] imx-uart 30860000.serial: We cannot prepare for the RX slave dma! > > When I get the above message, the bluetooth chip I have throws > timeouts and does not function. > > [ 10.615090] imx-sdma 302c0000.dma-controller: loaded firmware 4.5 > > Once the firmware is loaded, I can unload the HCI Uart driver and > re-load Bluetooth works again. > > Based on that, I've been having my system delay the loading of the > Bluetooth modules until after the firmware is loaded, but this tells > me there is a relationship between the DMA and UART. Yeah, I can see how DMA firmware impacts your Bluetooth device, but do not follow how this spba node change make a difference here. Nevertheless, patches look good. Applied, thanks. Shawn