From mboxrd@z Thu Jan 1 00:00:00 1970 From: heiko@sntech.de (Heiko Stuebner) Date: Tue, 16 Jun 2015 13:37:33 +0200 Subject: [PATCH] ARM: dts: rockchip: Add dmac_bus rx and tx for uart2 In-Reply-To: <1434390468-27296-1-git-send-email-romain.perier@gmail.com> References: <1434390468-27296-1-git-send-email-romain.perier@gmail.com> Message-ID: <34159914.9nlETdacuk@phil> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, Am Montag, 15. Juni 2015, 17:47:48 schrieb Romain Perier: > This removes warning "ttyS2 - Failed to request dma" from kernel logs > > Signed-off-by: Romain Perier > --- > arch/arm/boot/dts/rk3288.dtsi | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi > index 22316d0..816f40a 100644 > --- a/arch/arm/boot/dts/rk3288.dtsi > +++ b/arch/arm/boot/dts/rk3288.dtsi > @@ -385,6 +385,8 @@ > clock-names = "baudclk", "apb_pclk"; > pinctrl-names = "default"; > pinctrl-0 = <&uart2_xfer>; > + dmas = <&dmac_bus_s 4>, <&dmac_bus_s 5>; > + dma-names = "tx", "rx"; > status = "disabled"; > }; The dma channels are a property of the hardware, so we probably should add them for all uarts in one go, instead of everytime something complains :-) in dmac_peri uart0: tx 1, rx 2 uart1: tx 3, rx 4 uart3: tx 7, rx 8 uart4: tx 9, rx 10 Just for the record and if anybody is interested to work in this, we have an issue with the dma implementation [0] that is not yet solved upstream. From what I've remember, that mostly got triggered on higher speeds, like higher spi-speeds or i2s audio stuff (poping). Heiko [0] https://chromium.googlesource.com/chromiumos/third_party/kernel/+/93c3b192dca7e8c773c4d28873114c325382b63e%5E%21/#F0