xavier nx平台调试spi从模式1

1. 前言

想运行spi测试通过连接的spi1和spi3的jetson xavier nx板。
在连接spi1-spi3之前，我连接了spi1的MOSI-MISO (spi3的MOSI-MISO)，
并使用spidev_test.c示例进行了测试，以确认tx rx在spi1和spi3上都可以正常工作。

刚开始调试时有以下几个问题

（1）连接spi1和spi3时，如何设置主模式和从模式?
是否更新pinmux吗?

（2）下面两种方法之间的spi1-spi3如何连接?

a. spi1 MISO <-> spi3 MISO / spi1 MOSI <-> spi3 MOSI / spi1 SCK<-> spi3 SCK / spi1 CS0 <-> spi CS0
b. spi1 MISO <-> spi3 MOSI / spi1 MOSI <-> spi3 MISO / spi1 SCK<-> spi3 SCK / spi1 CS0 <-> spi CS0

(3)如何做rx在spi 从模式?
当数据进入时是否出现中断?
查看spi示例(spidev_test.c)， ioctl(fd, SPI_IOC_MESSAGE(1)， &tr)用于检查tx和rx。
这是检查rx的唯一方法吗?

2. 参考方法

（1）配置如下

将tegra124-spi-slave添加到设备树中。
使用两个xavier，一个用于master，另一个用于slave

这是master dts

spi0: spi@3210000 {
compatible = “nvidia,tegra186-spi”;
reg = <0x0 0x03210000 0x0 0x10000>;
interrupts = <0 36 0x04>;
#address-cells = <1>;
#size-cells = <0>;
iommus = <&smmu TEGRA_SID_GPCDMA_0>;
dma-coherent;
dmas = <&gpcdma 15>, <&gpcdma 15>;
dma-names = “rx”, “tx”;
nvidia,dma-request-selector = <&gpcdma 15>;
spi-max-frequency = <65000000>;
nvidia,clk-parents = “pll_p”, “clk_m”;
clocks = <&bpmp_clks TEGRA194_CLK_SPI1>,
<&bpmp_clks TEGRA194_CLK_PLLP_OUT0>,
<&bpmp_clks TEGRA194_CLK_CLK_M>;
clock-names = “spi”, “pll_p”, “clk_m”;
resets = <&bpmp_resets TEGRA194_RESET_SPI1>;
reset-names = “spi”;
status = “okay”;
nvidia,clock-always-on;
spi@0 {
compatible = “spidev”;
reg = <0>;
spi-max-frequency = <65000000>;
status = “okay”;
};
    };

这是slave dts

spi0: spi@3210000 {
compatible = “nvidia,tegra124-spi-slave”;
reg = <0x0 0x03210000 0x0 0x10000>;
interrupts = <0 36 0x04>;
#address-cells = <1>;
#size-cells = <0>;
iommus = <&smmu TEGRA_SID_GPCDMA_0>;
dma-coherent;
dmas = <&gpcdma 15>, <&gpcdma 15>;
dma-names = “rx”, “tx”;
nvidia,dma-request-selector = <&gpcdma 15>;
spi-max-frequency = <65000000>;
nvidia,clk-parents = “pll_p”, “clk_m”;
clocks = <&bpmp_clks TEGRA194_CLK_SPI1>,
<&bpmp_clks TEGRA194_CLK_PLLP_OUT0>,
<&bpmp_clks TEGRA194_CLK_CLK_M>;
clock-names = “spi”, “pll_p”, “clk_m”;
resets = <&bpmp_resets TEGRA194_RESET_SPI1>;
reset-names = “spi”;
status = “okay”;
nvidia,clock-always-on;
spi@0 {
compatible = “spidev”;
reg = <0>;
spi-max-frequency = <65000000>;
nvidia,slave-ready-gpio=<&tegra_main_gpio TEGRA194_MAIN_GPIO(T, 3) 0>;
nvidia,enable-hw-based-cs;
status = “okay”;
};
};

（2）测试方法

打开SSH终端，首先用下面的命令启动spi从属

．/spidev_test -D /dev/spidev0.0 -s 150000 -n100 -g30 -p4 -z

在另一个终端中，使用以下命令启动spi master

./spidev_test -D /dev/spidev3.1 -s 150000 -n100 -g30 -p4 -z

3. 调试记录

继续以下方式修改dts。
（1）执行/opt/nvidia/jetson-io/jetson-io.py命令，激活spi1、spi3

（2）

sudo dtc -I dts -O dtb -o ~/user-custom.dts /boot/tegra194-p3668-all-p3509-0000-user-custom.dtb

（3）修改user-custom.dts

spi@3210000 {
compatible = “nvidia,tegra186-spi”;
reg = <0x0 0x3210000 0x0 0x10000>;
interrupts = <0x0 0x24 0x4>;
#address-cells = <0x1>;
#size-cells = <0x0>;
iommus = <0x2 0x20>;
dma-coherent;
dmas = <0x19 0xf 0x19 0xf>;
dma-names = “rx”, “tx”;
spi-max-frequency = <0x3dfd240>;
nvidia,clk-parents = “pll_p”, “clk_m”;
clocks = <0x4 0x87 0x4 0x66 0x4 0xe>;
clock-names = “spi”, “pll_p”, “clk_m”;
resets = <0x5 0x5b>;
reset-names = “spi”;
status = “okay”;
linux,phandle = <0xf2>;
phandle = <0xf2>;
spi@0 {
compatible = “spidev”;
reg = <0x0>;
spi-max-frequency = <0x2faf080>;
controller-data {
nvidia,enable-hw-based-cs;
nvidia,rx-clk-tap-delay = <0x10>;
nvidia,tx-clk-tap-delay = <0x0>;
};
};
spi@1 {
compatible = “spidev”;
reg = <0x1>;
spi-max-frequency = <0x2faf080>;
controller-data {
nvidia,enable-hw-based-cs;
nvidia,rx-clk-tap-delay = <0x10>;
nvidia,tx-clk-tap-delay = <0x0>;
};
};
};
spi@3230000 {
compatible = “nvidia,tegra186-spi-slave”;
reg = <0x0 0x3230000 0x0 0x10000>;
interrupts = <0x0 0x26 0x4>;
#address-cells = <0x1>;
#size-cells = <0x0>;
iommus = <0x2 0x20>;
dma-coherent;
dmas = <0x19 0x11 0x19 0x11>;
dma-names = “rx”, “tx”;
spi-max-frequency = <0x3dfd240>;
nvidia,clk-parents = “pll_p”, “clk_m”;
clocks = <0x4 0x89 0x4 0x66 0x4 0xe>;
clock-names = “spi”, “pll_p”, “clk_m”;
resets = <0x5 0x5d>;
reset-names = “spi”;
status = “okay”;
linux,phandle = <0xf4>;
phandle = <0xf4>;
spi@0 {
compatible = “spidev”;
reg = <0x0>;
spi-max-frequency = <0x2faf080>;
controller-data {
nvidia,enable-hw-based-cs;
nvidia,rx-clk-tap-delay = <0x10>;
nvidia,tx-clk-tap-delay = <0x0>;
};
};
spi@1 {
compatible = “spidev”;
reg = <0x1>;
spi-max-frequency = <0x2faf080>;
controller-data {
nvidia,enable-hw-based-cs;
nvidia,rx-clk-tap-delay = <0x10>;
nvidia,tx-clk-tap-delay = <0x0>;
};
};
};

（4）

sudo dtc -I dts -O dtb -o /boot/tegra194-p3668-all-p3509-0000-user-custom.dtb ~/user-custom.dts

（5）reboot

通过以这种方式修改dts, spi1(master, spidev0.0)、spi3(slave, spidev2.0)被连接并按如下方式执行。

/spidev_test -D /dev/spidev2.0 -s 150000 -n10000 -g30 -p4 -z
./spidev_test -D /dev/spidev0.0 -s 150000 -n10000 -g30 -p4 -z

结果如图所示

当我在从模式运行它，一个传输错误发生和主测试失败。

(5)让devmem2读取那些REG来确认设置。

使用了devmem2来临时更改寄存器值。

检查dmesg时，出现以下错误。

[ 280.340212] spi-tegra124-slave 3230000.spi: Tx is not supported in mode 0
[ 280.340215] spi-tegra124-slave 3230000.spi: spi can not start transfer, err -22
[ 280.340301] spi_master spi2: failed to transfer one message from queue