1.实验原理
参考原理图可知eMMC使用的是sdmmc2总线,当前所使用的设备树文件中没有sdmmc2的支持,所以需要增加相关内容才能正常驱动eMMC。
由于在使STM32MP1芯片很多管脚为多功能复用管脚,且很多管脚具备同样的功能,所以移植eMMC时需要确认硬件设计是使用的是那些管脚,根据原理图确认后管脚对应关系为:
1.eMMC设备树节点
内核中ST对STM32MP15x系列芯片的设备树资源了做了定义,可参见:
- arch/arm/boot/dts/stm32mp151.dtsi
- stm32mp151中sdmmc2定义如下:
- sdmmc2: sdmmc@58007000 {
- compatible = "arm,pl18x", "arm,primecell";
- arm,primecell-periphid = <0x00253180>;
- reg = <0x58007000 0x1000>, <0x58008000 0x1000>;
- interrupts = <GIC_SPI 124 IRQ_TYPE_LEVEL_HIGH>;
- interrupt-names = "cmd_irq";
- clocks = <&rcc SDMMC2_K>;
- clock-names = "apb_pclk";
- resets = <&rcc SDMMC2_R>;
- cap-sd-highspeed;
- cap-mmc-highspeed;
- max-frequency = <120000000>;
- status = "disabled";
- };
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上述代码只对sdmmc2做了基本的初始化,并没有针对不同的硬件设计做适配,所以需结合硬件补全设备树节点信息。
eMMC有8根数据线,且eMMC无需热插拔等功能,结合硬件信息添加sdmmc2节点信息,也可参考内核中其他设备树文件中相关描述,比如stm32mp15xx-edx.dtsi关于sdmmc2的描述符合我们的要求,内容如下:
- &sdmmc2 {
- pinctrl-names = "default", "opendrain", "sleep";
- pinctrl-0 = <&sdmmc2_b4_pins_a &sdmmc2_d47_pins_a>;
- pinctrl-1 = <&sdmmc2_b4_od_pins_a &sdmmc2_d47_pins_a>;
- pinctrl-2 = <&sdmmc2_b4_sleep_pins_a &sdmmc2_d47_sleep_pins_a>;
- non-removable;
- no-sd;
- no-sdio;
- st,neg-edge;
- bus-width = <8>;
- vmmc-supply = <&v3v3>;
- vqmmc-supply = <&vdd>;
- mmc-ddr-3_3v;
- status = "okay";
- };
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2.管脚定义
在内核中STM32MP1默认管脚定义在文件arch/arm/dts/stm32mp15-pinctrl.dtsi中,查看文件中是否有需要的管脚定义:
查看后确认有sdmmc2的管脚定义,且与FS-MP1A硬件使用情况一致,定义如下:
- sdmmc2_b4_pins_a: sdmmc2-b4-0 {
- pins1 {
- pinmux = <STM32_PINMUX('B', 14, AF9)>, /* SDMMC2_D0 */
- <STM32_PINMUX('B', 15, AF9)>, /* SDMMC2_D1 */
- <STM32_PINMUX('B', 3, AF9)>, /* SDMMC2_D2 */
- <STM32_PINMUX('B', 4, AF9)>, /* SDMMC2_D3 */
- <STM32_PINMUX('G', 6, AF10)>; /* SDMMC2_CMD */
- slew-rate = <1>;
- drive-push-pull;
- bias-pull-up;
- };
- pins2 {
- pinmux = <STM32_PINMUX('E', 3, AF9)>; /* SDMMC2_CK */
- slew-rate = <2>;
- drive-push-pull;
- bias-pull-up;
- };
- };
- sdmmc2_b4_od_pins_a: sdmmc2-b4-od-0 {
- pins1 {
- pinmux = <STM32_PINMUX('B', 14, AF9)>, /* SDMMC2_D0 */
- <STM32_PINMUX('B', 15, AF9)>, /* SDMMC2_D1 */
- <STM32_PINMUX('B', 3, AF9)>, /* SDMMC2_D2 */
- <STM32_PINMUX('B', 4, AF9)>; /* SDMMC2_D3 */
- slew-rate = <1>;
- drive-push-pull;
- bias-pull-up;
- };
- pins2 {
- pinmux = <STM32_PINMUX('E', 3, AF9)>; /* SDMMC2_CK */
- slew-rate = <2>;
- drive-push-pull;
- bias-pull-up;
- };
- pins3 {
- pinmux = <STM32_PINMUX('G', 6, AF10)>; /* SDMMC2_CMD */
- slew-rate = <1>;
- drive-open-drain;
- bias-pull-up;
- };
- };
- sdmmc2_b4_sleep_pins_a: sdmmc2-b4-sleep-0 {
- pins {
- pinmux = <STM32_PINMUX('B', 14, ANALOG)>, /* SDMMC2_D0 */
- <STM32_PINMUX('B', 15, ANALOG)>, /* SDMMC2_D1 */
- <STM32_PINMUX('B', 3, ANALOG)>, /* SDMMC2_D2 */
- <STM32_PINMUX('B', 4, ANALOG)>, /* SDMMC2_D3 */
- <STM32_PINMUX('E', 3, ANALOG)>, /* SDMMC2_CK */
- <STM32_PINMUX('G', 6, ANALOG)>; /* SDMMC2_CMD */
- };
- };
- sdmmc2_b4_pins_b: sdmmc2-b4-1 {
- pins1 {
- pinmux = <STM32_PINMUX('B', 14, AF9)>, /* SDMMC2_D0 */
- <STM32_PINMUX('B', 15, AF9)>, /* SDMMC2_D1 */
- <STM32_PINMUX('B', 3, AF9)>, /* SDMMC2_D2 */
- <STM32_PINMUX('B', 4, AF9)>, /* SDMMC2_D3 */
- <STM32_PINMUX('G', 6, AF10)>; /* SDMMC2_CMD */
- slew-rate = <1>;
- drive-push-pull;
- bias-disable;
- };
- pins2 {
- pinmux = <STM32_PINMUX('E', 3, AF9)>; /* SDMMC2_CK */
- slew-rate = <2>;
- drive-push-pull;
- bias-disable;
- };
- };
- sdmmc2_b4_od_pins_b: sdmmc2-b4-od-1 {
- pins1 {
- pinmux = <STM32_PINMUX('B', 14, AF9)>, /* SDMMC2_D0 */
- <STM32_PINMUX('B', 15, AF9)>, /* SDMMC2_D1 */
- <STM32_PINMUX('B', 3, AF9)>, /* SDMMC2_D2 */
- <STM32_PINMUX('B', 4, AF9)>; /* SDMMC2_D3 */
- slew-rate = <1>;
- drive-push-pull;
- bias-disable;
- };
- pins2 {
- pinmux = <STM32_PINMUX('E', 3, AF9)>; /* SDMMC2_CK */
- slew-rate = <2>;
- drive-push-pull;
- bias-disable;
- };
- pins3 {
- pinmux = <STM32_PINMUX('G', 6, AF10)>; /* SDMMC2_CMD */
- slew-rate = <1>;
- drive-open-drain;
- bias-disable;
- };
- };
- sdmmc2_d47_pins_a: sdmmc2-d47-0 {
- pins {
- pinmux = <STM32_PINMUX('A', 8, AF9)>, /* SDMMC2_D4 */
- <STM32_PINMUX('A', 9, AF10)>, /* SDMMC2_D5 */
- <STM32_PINMUX('E', 5, AF9)>, /* SDMMC2_D6 */
- <STM32_PINMUX('D', 3, AF9)>; /* SDMMC2_D7 */
- slew-rate = <1>;
- drive-push-pull;
- bias-pull-up;
- };
- };
- sdmmc2_d47_sleep_pins_a: sdmmc2-d47-sleep-0 {
- pins {
- pinmux = <STM32_PINMUX('A', 8, ANALOG)>, /* SDMMC2_D4 */
- <STM32_PINMUX('A', 9, ANALOG)>, /* SDMMC2_D5 */
- <STM32_PINMUX('E', 5, ANALOG)>, /* SDMMC2_D6 */
- <STM32_PINMUX('D', 3, ANALOG)>; /* SDMMC2_D7 */
- };
- };
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2.实验目的
熟悉基于Linux操作系统下的块设备驱动移植配置过程。
3.实验平台
FS-MP1A平台;
4.实验步骤
1.导入交叉编译工具链
linux@ubuntu source /opt/st/stm32mp1/3.1-openstlinux-5.4-dunfell-mp1-20-06-24/environment-setup-cortexa7t2hf-neon-vfpv4-ostl-linux-gnueabi
2.添加eMMC设备树配置
修改arch/arm/boot/dts/stm32mp15xx-fsmp1x.dtsi文件
在原有sdmmc1节点下添加如下内容:
- &sdmmc2 {
- pinctrl-names = "default", "opendrain", "sleep";
- pinctrl-0 = <&sdmmc2_b4_pins_a &sdmmc2_d47_pins_a>;
- pinctrl-1 = <&sdmmc2_b4_od_pins_a &sdmmc2_d47_pins_a>;
- pinctrl-2 = <&sdmmc2_b4_sleep_pins_a &sdmmc2_d47_sleep_pins_a>;
- non-removable;
- no-sd;
- no-sdio;
- st,neg-edge;
- bus-width = <8>;
- vmmc-supply = <&v3v3>;
- vqmmc-supply = <&vdd>;
- mmc-ddr-3_3v;
- status = "okay";
- };
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3.配置内核
由于内核源码默认配置已经支持eMMC,本节列出主要选项,如下
linux@ubuntu make menuconfig
Device Drivers --->
<*> MMC/SD/SDIO card support --->
STMicroelectronics STM32 SDMMC Controller
4.编译内核级设备树:
linux@ubuntu make -j4 uImage dtbs LOADADDR=0xC2000040
5.重启测试
将编译好的设备树和内核镜像拷贝到/tftpboot目录下,通过tftp引导内核,重启设备后可以看到如下启动信息:
由于eMMC中有出厂预
装的FS-MP1A系统,所以可以正常完成文件系统挂载进入系统:
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