linux_dsm_epyc7002/Documentation/devicetree/bindings/serial/fsl-imx-uart.txt
Nandor Han a3015affdf serial: imx-serial - move DMA buffer configuration to DT
The size of the DMA buffer can affect the delta time between data being
produced and data being consumed. Basically the DMA system will move
data to tty buffer when a) DMA buffer is full b) serial line is idle.
The situation is visible when producer generates data continuously and
there is no possibility for idle line. At this point the DMA buffer is
directly affecting the delta time.

The patch will add the possibility to configure the DMA buffers in DT,
which case by case can be configured separately for every driver
instance. The DT configuration is optional and in case missing the
driver will use the 4096 buffer with 4 periods (as before), therefore no
clients are impacted by this change.

Signed-off-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Romain Perier <romain.perier@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-29 17:08:01 +02:00

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* Freescale i.MX Universal Asynchronous Receiver/Transmitter (UART)
Required properties:
- compatible : Should be "fsl,<soc>-uart"
- reg : Address and length of the register set for the device
- interrupts : Should contain uart interrupt
Optional properties:
- fsl,irda-mode : Indicate the uart supports irda mode
- fsl,dte-mode : Indicate the uart works in DTE mode. The uart works
in DCE mode by default.
- fsl,dma-size : Indicate the size of the DMA buffer and its periods
Please check Documentation/devicetree/bindings/serial/serial.txt
for the complete list of generic properties.
Note: Each uart controller should have an alias correctly numbered
in "aliases" node.
Example:
aliases {
serial0 = &uart1;
};
uart1: serial@73fbc000 {
compatible = "fsl,imx51-uart", "fsl,imx21-uart";
reg = <0x73fbc000 0x4000>;
interrupts = <31>;
uart-has-rtscts;
fsl,dte-mode;
fsl,dma-size = <1024 4>;
};