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SubjectRe: [patch v4 3/5] DT nodes for AST2500 DMA UART driver
On Fri, Jul 26, 2019 at 7:25 AM sudheer.v <open.sudheer@gmail.com> wrote:
>
> From: sudheer veliseti <sudheer.open@gmail.com>
>
> DT node for DMA controller(ast_uart_sdma) doesn't bind to any DMA controller driver.
> This is because Software for DMA controller is not based on DMA framework,but is dedicated
> and serves only UARTs in AST2500. ast_uart_sdma node is searched by compatible string in the
> driver software.basic use of this node is to provide register base address of DMA controller and DMA irq number(<50>).
> IRQ of DMA controller is of crucial importance, which does RX and TX of UART data.
>
> uart nodes dma_uart1,2...etc binds to the platform driver.
> irq numbers <9>,<32>,<33>,<34> in dma_uart nodes install ISRs which are of not much interest in uart data TX/RX .
>
>
> Signed-off-by: sudheer veliseti <sudheer.open@gmail.com>
> ---
>
> changes from v3->v4:
> -
> changes from v2->v3:
> - change logs added
>
> arch/arm/boot/dts/aspeed-ast2500-evb.dts | 21 +++++++
> arch/arm/boot/dts/aspeed-g5.dtsi | 71 ++++++++++++++++++++++--
> 2 files changed, 88 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/boot/dts/aspeed-ast2500-evb.dts b/arch/arm/boot/dts/aspeed-ast2500-evb.dts
> index 5dbb33c10c4f..4da09fbe94df 100644
> --- a/arch/arm/boot/dts/aspeed-ast2500-evb.dts
> +++ b/arch/arm/boot/dts/aspeed-ast2500-evb.dts
> @@ -64,6 +64,27 @@
> status = "okay";
> };
>
> +&ast_uart_sdma {
> + status = "okay";
> +};
> +
> +&dma_uart1 {
> + status = "okay";
> +};
> +
> +&dma_uart2 {
> + status = "okay";
> +};
> +
> +&dma_uart3 {
> + status = "okay";
> +};
> +
> +&dma_uart4 {
> + status = "okay";
> +};
> +
> +
> &mac0 {
> status = "okay";
>
> diff --git a/arch/arm/boot/dts/aspeed-g5.dtsi b/arch/arm/boot/dts/aspeed-g5.dtsi
> index 674746513031..fb7b3ed463de 100644
> --- a/arch/arm/boot/dts/aspeed-g5.dtsi
> +++ b/arch/arm/boot/dts/aspeed-g5.dtsi
> @@ -23,10 +23,10 @@
> i2c11 = &i2c11;
> i2c12 = &i2c12;
> i2c13 = &i2c13;
> - serial0 = &uart1;
> - serial1 = &uart2;
> - serial2 = &uart3;
> - serial3 = &uart4;
> + serial0 = &dma_uart1;
> + serial1 = &dma_uart2;
> + serial2 = &dma_uart3;
> + serial3 = &dma_uart4;
> serial4 = &uart5;
> serial5 = &vuart;
> peci0 = &peci0;
> @@ -497,6 +497,69 @@
> status = "disabled";
> };
>
> + ast_uart_sdma: uart_sdma@1e79e000 {
> + compatible = "aspeed,ast-uart-sdma";
> + reg = <0x1e79e000 0x400>;
> + interrupts = <50>;
> + status = "disabled";
> + };
> +
> + dma_uart1: dma_uart1@1e783000{
> + compatible = "aspeed,ast-sdma-uart";
> + reg = <0x1e783000 0x1000>;

Now you have 2 nodes at the same address. That's not valid. Please
build your dtbs with 'W=1' which will warn against this. Adding DMA
support should not be a whole new node. Nodes correspond to h/w
blocks, not drivers.

The old node has a reset, you don't need that? Seems strange too that
only 1 uart has a reset.

> + reg-shift = <2>;
> + interrupts = <9>;
> + clocks = <&syscon ASPEED_CLK_GATE_UART1CLK>;
> + dma-channel = <0>;

This is the channel in ast_uart_sdma? Just because you decided not to
do a DMA engine driver, doesn't mean you can't use the DMA binding.
Considering you need to map clients to the provider, use the DMA
binding.

> + no-loopback-test;
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_txd1_default
> + &pinctrl_rxd1_default>;
> + status = "disabled";
> + };
> +
> + dma_uart2: dma_uart2@1e78d000{
> + compatible = "aspeed,ast-sdma-uart";
> + reg = <0x1e78d000 0x1000>;
> + reg-shift = <2>;
> + interrupts = <32>;
> + clocks = <&syscon ASPEED_CLK_GATE_UART2CLK>;
> + dma-channel = <1>;
> + no-loopback-test;
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_txd2_default
> + &pinctrl_rxd2_default>;
> + status = "disabled";
> + };
> +
> + dma_uart3: dma_uart3@1e78e000{
> + compatible = "aspeed,ast-sdma-uart";
> + reg = <0x1e78e000 0x1000>;
> + reg-shift = <2>;
> + interrupts = <33>;
> + clocks = <&syscon ASPEED_CLK_GATE_UART3CLK>;
> + dma-channel = <2>;
> + no-loopback-test;
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_txd3_default
> + &pinctrl_rxd3_default>;
> + status = "disabled";
> + };
> +
> + dma_uart4: dma_uart4@1e78f000{
> + compatible = "aspeed,ast-sdma-uart";
> + reg = <0x1e78f000 0x1000>;
> + reg-shift = <2>;
> + interrupts = <34>;
> + clocks = <&syscon ASPEED_CLK_GATE_UART4CLK>;
> + dma-channel = <3>;
> + no-loopback-test;
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_txd4_default
> + &pinctrl_rxd4_default>;
> + status = "disabled";
> + };
> +
> i2c: bus@1e78a000 {
> compatible = "simple-bus";
> #address-cells = <1>;
> --
> 2.17.1
>

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