From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Stuebner Subject: Re: [PATCH] arm64: dts: rockchip: fix rk3328 rgmii high tx error rate Date: Sat, 16 Mar 2019 21:00:24 +0100 Message-ID: <5627989.CJK7gzyIMr@phil> References: <20190313184535.15759-1-pgwipeout@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20190313184535.15759-1-pgwipeout-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+glpar-linux-rockchip=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Peter Geis Cc: linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Robin Murphy , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, "Leonidas P . Papadakos" List-Id: linux-rockchip.vger.kernel.org Am Mittwoch, 13. M=E4rz 2019, 19:45:36 CET schrieb Peter Geis: > Resubmitting, after further research, review, comments, and suggestions. > = > Several rk3328 based boards experience high rgmii tx error rates. > This is due to several pins in the rk3328.dtsi rgmii pinmux that are > missing a defined pull strength setting. > This causes the pinmux driver to default to 2ma (bit mask 00). > = > These pins are only defined in the rk3328.dtsi, and are not listed in > the rk3328 specification. > The TRM only lists them as "Reserved" > (RK3328 TRM V1.1, 3.3.3 Detail Register Description, GRF_GPIO0B_IOMUX, > GRF_GPIO0C_IOMUX, GRF_GPIO0D_IOMUX). > However, removal of these pins from the rgmii pinmux definition causes > the interface to fail to transmit. > = > Also, the rgmii tx and rx pins defined in the dtsi are not consistent > with the rk3328 specification, with tx pins currently set to 12ma and > rx pins set to 2ma. > = > Fix this by setting tx pins to 8ma and the rx pins to 4ma, consistent > with the specification. > Defining the drive strength for the undefined pins eliminated the high > tx packet error rate observed under heavy data transfers. > Aligning the drive strength to the TRM values eliminated the occasional > packet retry errors under iperf3 testing. > This allows much higher data rates with no recorded tx errors. > = > Tested on the rk3328-roc-cc board. > = > Signed-off-by: Peter Geis applied as fix for 5.1 after adding Fixes and Cc-stable-tags Thanks Heiko