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Disable DMA for Pi 5's UART0 #6742

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Merged
merged 2 commits into from
Mar 26, 2025
Merged

Disable DMA for Pi 5's UART0 #6742

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1428548
Revert "dts: bcm2712-rpi: Add uart0_nodma"
pelwell Mar 26, 2025
8258166
dts: rp1: Don't use DMA with UARTs
pelwell Mar 26, 2025
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6 changes: 1 addition & 5 deletions arch/arm/boot/dts/overlays/README
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Expand Up @@ -454,16 +454,12 @@ Params:
and entering the low power state (default 600).
Requires EEE to be enabled - see "eee".

uart0 Set to "on" to enable and "off" to disable uart0
(default "off" on 2712, otherwise "on")
uart0 Set to "off" to disable uart0 (default "on")

uart0_console Move the kernel boot console to UART0 on pins
6, 8 and 10 of the 40-way header (2712 only,
default "off")

uart0_nodma Enable uart0 without DMA (2712 only, default
"off")

uart1 Set to "on" or "off" to enable or disable uart1
(default varies)

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1 change: 0 additions & 1 deletion arch/arm64/boot/dts/broadcom/bcm2712-rpi.dtsi
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Expand Up @@ -220,7 +220,6 @@ pio: &rp1_pio {
suspend = <&pwr_key>, "linux,code:0=205";
uart0 = <&uart0>, "status";
uart0_console = <&uart0>,"status", <&aliases>, "console=",&uart0;
uart0_nodma = <&uart0>,"status", <&uart0>,"dma-names?=0";
wifiaddr = <&wifi>, "local-mac-address[";

cam0_reg = <&cam0_reg>,"status";
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6 changes: 3 additions & 3 deletions arch/arm64/boot/dts/broadcom/rp1.dtsi
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Expand Up @@ -65,9 +65,9 @@
interrupts = <RP1_INT_UART0 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&rp1_clocks RP1_CLK_UART &rp1_clocks RP1_PLL_SYS_PRI_PH>;
clock-names = "uartclk", "apb_pclk";
dmas = <&rp1_dma RP1_DMA_UART0_TX>,
<&rp1_dma RP1_DMA_UART0_RX>;
dma-names = "tx", "rx";
// dmas = <&rp1_dma RP1_DMA_UART0_TX>,
// <&rp1_dma RP1_DMA_UART0_RX>;
// dma-names = "tx", "rx";
pinctrl-names = "default";
arm,primecell-periphid = <0x00341011>;
uart-has-rtscts;
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