Re: [PATCH 0/6] Add support for BCM2712 SD card controller

From: Andrea della Porta <andrea.porta@suse.com>
To: Stefan Wahren <wahrenst@gmx.net>
Cc: Andrea della Porta <andrea.porta@suse.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Florian Fainelli <florian.fainelli@broadcom.com>,
	Broadcom internal kernel review list
	<bcm-kernel-feedback-list@broadcom.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Kamal Dasu <kamal.dasu@broadcom.com>,
	Al Cooper <alcooperx@gmail.com>,
	linux-mmc@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org,
	Jonathan Bell <jonathan@raspberrypi.com>,
	Phil Elwell <phil@raspberrypi.com>
Subject: Re: [PATCH 0/6] Add support for BCM2712 SD card controller
Date: Thu, 2 May 2024 11:12:06 +0200	[thread overview]
Message-ID: <ZjNY5qY4ABOB3lv2@apocalypse> (raw)
In-Reply-To: <fd77cfa2-9bd8-4393-95bd-eced676bf6d2@gmx.net>

On 12:07 Sun 14 Apr     , Stefan Wahren wrote:
> Hi Andrea,
> 
> Am 14.04.24 um 00:14 schrieb Andrea della Porta:
> > Hi,
> > 
> > This patchset adds support for the SDHCI controller on Broadcom BCM2712
> > SoC in order to make it possible to boot (particularly) Raspberry Pi 5
> > from SD card. This work is heavily based on downstream contributions.
> since your goal is minimal Raspberry Pi 5 support, i suggest to use this
> as the subject for this patch.
> > Patch #1 and 2: introduce the dt binding definitions for, respectively,
> > the new pin cfg/mux controller and the SD host controller as a preparatory
> > step for the upcoming dts.
> > 
> > Patch #3: add a somewhat reasonable (*almost* bare-minimum) dts to be used
> > to boot Rpi5 boards. Since till now there was no support at all for any
> > 2712 based chipset, both the SoC and board dts plus definitions for the
> > new Pin and SD host controller have been added.
> The patch still seems to contain a lot unnecessary stuff (Wifi, BT,
> SPI), please try to remove as much as possible for the minimal support
> (just boot via debug UART & SD card) in order to make review easier. Btw
> this patch must be after pinctrl & SDHCI support.
> > Patch #4: the driver supporting the pin controller. Based on [1] and
> > successive fix commits.
> > 
> > Patch #5: add SDHCI support. Based on [2] and the next 2 fix commits.
> > Drop the SD Express implementation for now, that will be added by patch
> > #6.
> > 
> > Patch #6: this patch offers SD Express support and can be considered totally
> > optional. The callback plumbing is slightly different w.r.t. the downstream
> > approach (see [3]), as explained in the patch comment. Not sure what is the best,
> > any comment is highly appreciated.
> I don't think this should be necessary for minimal Raspberry Pi 5
> support. Maybe this should be addressed later.

Thanks for all the feedback. Just a quick note to let you know that
I'm working on V2 patchset that will fix all coding-style and dts/binding
issues. The new patchset will be significantly smaller and I managed
to remove everything that is not strictly needed in order to be able to
boot an rpi5 from sd card.

Best regards,
Andrea