I want to know how to disable the DMA function of the UART. The kernel version is 3.14.52.

[志林韩]

Just need some help, please.

[igorpadykov · Accepted solution]

Hi

as described in sect.45.2.1 Software Operation attached Linux Manual:

Each UART can be configured to use DMA for the data transfer by enabling the DMA
channel in the DTS file.

imx6qdl.dtsi\dts\boot\arm\arch - linux-imx - i.MX Linux kernel 

Best regards
igor
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[志林韩]

Status = "disabled" means that the dma function is disabled? I‘m a rookie -_-

uart2: serial@021e8000 {                     compatible = "fsl,imx6q-uart", "fsl,imx21-uart";                     reg = <0x021e8000 0x4000>;                     interrupts = <0 27 IRQ_TYPE_LEVEL_HIGH>;                     clocks = <&clks IMX6QDL_CLK_UART_IPG>,                           <&clks IMX6QDL_CLK_UART_SERIAL>;                     clock-names = "ipg", "per";                     dmas = <&sdma 27 4 0>, <&sdma 28 4 0>;                     dma-names = "rx", "tx";                     status = "disabled";                };

[vivsundar]

Finally how did you disable the DMA for UART.  Can you post it?