Re: [PATCH v2 2/4] can: rockchip: add RK3588 CAN support

From: "Heiko Stübner" <heiko@sntech.de>
To: Marc Kleine-Budde <mkl@pengutronix.de>,
	linux-can <linux-can@vger.kernel.org>,
	1579567540@qq.com
Cc: Vincent Mailhol <mailhol@kernel.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	kernel <kernel@pengutronix.de>,
	Conor Dooley <conor+dt@kernel.org>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Shengjiu Wang <shengjiu.wang@nxp.com>,
	Pengpeng Hou <pengpeng@iscas.ac.cn>,
	Russell King <rmk+kernel@armlinux.org.uk>,
	Eric Biggers <ebiggers@kernel.org>,
	Mario Limonciello <mario.limonciello@amd.com>,
	Karl Mehltretter <kmehltretter@gmail.com>,
	Yixun Lan <dlan@kernel.org>, Stephen Boyd <sboyd@kernel.org>,
	devicetree <devicetree@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	linux-rockchip <linux-rockchip@lists.infradead.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Cunhao Lu <1579567540@qq.com>,
	Heiko Stuebner <heiko.stuebner@cherry.de>
Subject: Re: [PATCH v2 2/4] can: rockchip: add RK3588 CAN support
Date: Thu, 02 Jul 2026 18:02:25 +0200	[thread overview]
Message-ID: <3527453.usfYGdeWWP@diego> (raw)
In-Reply-To: <tencent_F077D309CDB6CC4802CC086D8009E29BDF06@qq.com>

Am Donnerstag, 2. Juli 2026, 16:06:52 Mitteleuropäische Sommerzeit schrieb 1579567540@qq.com:
> From: Cunhao Lu <1579567540@qq.com>
> 
> Add support for the RK3588 CAN controller by introducing a dedicated
> model ID and OF match entry.
> 
> The block is closely related to the existing RK3568 variants, but it
> cannot reuse their match data unchanged. In particular, RK3588
> encodes RX_FIFO_CNT in bits 7:5 instead of 6:4, so the RX path needs
> SoC-specific handling.
> 
> The RX FIFO count bitfield difference was found by comparing Rockchip's
> vendor kernel 6.1 CAN support for RK3568 and RK3588. Runtime testing on
> RK3588 also confirms that bits 7:5 are needed.
> 
> Enable the existing erratum 5 empty-FIFO workaround for RK3588.
> Heiko reproduced erratum 6 on RK3588, so enable that workaround as
> well.
> 
> Keep RKCANFD_QUIRK_CANFD_BROKEN enabled for RK3588, so CAN-FD stays
> disabled for now. Local testing did not reproduce the two known CAN-FD
> trigger frames that cause Error Interrupts on RK3568 variants. Instead,
> RK3588 shows a different CAN-FD failure mode: CAN-FD frames without BRS
> work in this setup, but BRS with a data bitrate different from the
> nominal bitrate immediately drives the controller bus-off.
> 
> Reported-by: Heiko Stuebner <heiko.stuebner@cherry.de>
> Link: https://lore.kernel.org/lkml/20260630164336.3444550-4-heiko@sntech.de/

I think you might want to drop that above. If anything a Co-developed-by
would be applicable, but from the (small) size of the change, that also
isn't really necessary for me :-)

> Signed-off-by: Cunhao Lu <1579567540@qq.com>

Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>