SD/SDIO/MMC 驱动程序

[English]

概述

SD/SDIO/MMC 驱动目前支持 SD 存储器、SDIO 卡和 eMMC 芯片。这是一个协议层驱动 (sdmmc/include/sdmmc_cmd.h),可以由以下方式实现:

协议层与主机层

本文中的 SDMMC 协议层能处理 SD 协议的具体细节,例如卡初始化流程和各种数据传输命令流程。该协议层通过 sdmmc_host_t 结构体与主机通信。该结构体包含指向主机各种功能的指针。

主机驱动通过支持以下功能来实现协议驱动:

  • 发送命令至从设备

  • 接收和发送数据

  • 处理总线错误

SD 主机端组件架构

应用示例

ESP-IDF storage/sd_card 目录下提供了 SDMMC 驱动与 FatFs 库组合使用的示例,演示了先初始化卡,然后使用 POSIX 和 C 库 API 向卡读写数据。请参考示例目录下 README.md 文件,查看更多详细信息。

复合卡(存储 + IO)

该驱动程序不支持 SD 复合卡,复合卡会被视为 IO 卡。

线程安全

多数应用程序仅需在一个任务中使用协议层。因此,协议层在 sdmmc_card_t 结构体或在访问 SDMMC 或 SD SPI 主机驱动程序时不使用任何类型的锁。这种锁通常在较高层级实现,例如文件系统驱动程序。

协议层 API

协议层具备 sdmmc_host_t 结构体,此结构体描述了 SD/MMC 主机驱动,列出了其功能,并提供指向驱动程序函数的指针。协议层将卡信息储存于 sdmmc_card_t 结构体中。向 SD/MMC 主机发送命令时,协议层使用 sdmmc_command_t 结构体来描述命令、参数、预期返回值和需传输的数据(如有)。

用于 SD 存储卡的 API

  1. 初始化主机,请调用主机驱动函数,例如 sdmmc_host_init()sdmmc_host_init_slot()

  2. 初始化卡,请调用 sdmmc_card_init(),并将参数 host (主机驱动信息)和参数 card (指向 sdmmc_card_t 结构体的指针)传递给此函数。函数运行结束后,将会向 sdmmc_card_t 结构体填充该卡的信息;

  3. 读取或写入卡的扇区,请分别调用 sdmmc_read_sectors()sdmmc_write_sectors(),并将参数 card (指向卡信息结构的指针)传递给函数;

  4. 如果不再使用该卡,请调用主机驱动函数,例如 sdmmc_host_deinit(),以禁用主机外设,并释放驱动程序分配的资源。

用于 eMMC 芯片的 API

从协议层的角度而言,eMMC 存储芯片与 SD 存储卡相同。尽管 eMMC 是芯片,不具备卡的外形,但由于协议相似 (sdmmc_card_t, sdmmc_card_init),用于 SD 卡的一些概念同样适用于 eMMC 芯片。注意,eMMC 芯片不可通过 SPI 使用,因此它与 SD SPI 主机驱动不兼容。

如需初始化 eMMC 内存并执行读/写操作,请参照上一章节 SD 卡操作步骤。

用于 SDIO 卡的 API

SDIO 卡初始化和检测过程与 SD 存储卡相同,唯一的区别是 SDIO 模式下数据传输命令不同。

在卡初始化和卡检测(通过运行 sdmmc_card_init())期间,驱动仅配置 IO 卡如下寄存器:

  1. I/O 中止 (0x06) 寄存器:在该寄存器中设置 RES 位可重置卡的 IO 部分;

  2. 总线接口控制 (0x07) 寄存器:如果主机和插槽配置中启用 4 线模式,则驱动程序会尝试在该寄存器中设置总线宽度字段。如果字段设置成功,则从机支持 4 线模式,主机也切换至 4 线模式;

  3. 高速 (0x13) 寄存器:如果主机配置中启用高速模式,则该寄存器的 SHS 位会被设置。

注意,驱动程序不会在 (1) I/O 使能寄存器和 Int 使能寄存器,及 (2) I/O 块大小中,设置任何位。应用程序可通过调用 sdmmc_io_write_byte() 来设置相关位。

如需卡配置或传输数据,请根据具体情况,选择下表函数:

操作

函数读取

函数写入

使用 IO_RW_DIRECT (CMD52) 读写单个字节。

sdmmc_io_read_byte()

sdmmc_io_write_byte()

使用 IO_RW_EXTENDED (CMD53) 的字节模式读写多个字节。

sdmmc_io_read_bytes()

sdmmc_io_write_bytes()

块模式下,使用 IO_RW_EXTENDED (CMD53) 读写数据块。

sdmmc_io_read_blocks()

sdmmc_io_write_blocks()

使用 sdmmc_io_enable_int() 函数,应用程序可启用 SDIO 中断。在单线模式下使用 SDIO 时,还需要连接 D1 线来启用 SDIO 中断。

如果需要应用程序保持等待直至发生 SDIO 中断,请使用 sdmmc_io_wait_int() 函数。

如果需要与 ESP32 的 SDIO 从设备通信,请使用 ESSL 组件(ESP 串行从设备链接)。请参阅 ESP 串行从机链路peripherals/sdio/host

API 参考

Header File

  • components/sdmmc/include/sdmmc_cmd.h

  • This header file can be included with:

    #include "sdmmc_cmd.h"
    
  • This header file is a part of the API provided by the sdmmc component. To declare that your component depends on sdmmc, add the following to your CMakeLists.txt:

    REQUIRES sdmmc
    

    or

    PRIV_REQUIRES sdmmc
    

Functions

esp_err_t sdmmc_card_init(const sdmmc_host_t *host, sdmmc_card_t *out_card)

Probe and initialize SD/MMC card using given host

备注

Only SD cards (SDSC and SDHC/SDXC) are supported now. Support for MMC/eMMC cards will be added later.

参数
  • host -- pointer to structure defining host controller

  • out_card -- pointer to structure which will receive information about the card when the function completes

返回

  • ESP_OK on success

  • One of the error codes from SDMMC host controller

void sdmmc_card_print_info(FILE *stream, const sdmmc_card_t *card)

Print information about the card to a stream.

参数
  • stream -- stream obtained using fopen or fdopen

  • card -- card information structure initialized using sdmmc_card_init

esp_err_t sdmmc_get_status(sdmmc_card_t *card)

Get status of SD/MMC card

参数

card -- pointer to card information structure previously initialized using sdmmc_card_init

返回

  • ESP_OK on success

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_write_sectors(sdmmc_card_t *card, const void *src, size_t start_sector, size_t sector_count)

Write given number of sectors to SD/MMC card

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • src -- pointer to data buffer to read data from; data size must be equal to sector_count * card->csd.sector_size

  • start_sector -- sector where to start writing

  • sector_count -- number of sectors to write

返回

  • ESP_OK on success or sector_count equal to 0

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_read_sectors(sdmmc_card_t *card, void *dst, size_t start_sector, size_t sector_count)

Read given number of sectors from the SD/MMC card

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • dst -- pointer to data buffer to write into; buffer size must be at least sector_count * card->csd.sector_size

  • start_sector -- sector where to start reading

  • sector_count -- number of sectors to read

返回

  • ESP_OK on success or sector_count equal to 0

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_erase_sectors(sdmmc_card_t *card, size_t start_sector, size_t sector_count, sdmmc_erase_arg_t arg)

Erase given number of sectors from the SD/MMC card

备注

When sdmmc_erase_sectors used with cards in SDSPI mode, it was observed that card requires re-init after erase operation.

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • start_sector -- sector where to start erase

  • sector_count -- number of sectors to erase

  • arg -- erase command (CMD38) argument

返回

  • ESP_OK on success or sector_count equal to 0

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_can_discard(sdmmc_card_t *card)

Check if SD/MMC card supports discard

参数

card -- pointer to card information structure previously initialized using sdmmc_card_init

返回

  • ESP_OK if supported by the card/device

  • ESP_FAIL if not supported by the card/device

esp_err_t sdmmc_can_trim(sdmmc_card_t *card)

Check if SD/MMC card supports trim

参数

card -- pointer to card information structure previously initialized using sdmmc_card_init

返回

  • ESP_OK if supported by the card/device

  • ESP_FAIL if not supported by the card/device

esp_err_t sdmmc_mmc_can_sanitize(sdmmc_card_t *card)

Check if SD/MMC card supports sanitize

参数

card -- pointer to card information structure previously initialized using sdmmc_card_init

返回

  • ESP_OK if supported by the card/device

  • ESP_FAIL if not supported by the card/device

esp_err_t sdmmc_mmc_sanitize(sdmmc_card_t *card, uint32_t timeout_ms)

Sanitize the data that was unmapped by a Discard command

备注

Discard command has to precede sanitize operation. To discard, use MMC_DICARD_ARG with sdmmc_erase_sectors argument

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • timeout_ms -- timeout value in milliseconds required to sanitize the selected range of sectors.

返回

  • ESP_OK on success

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_full_erase(sdmmc_card_t *card)

Erase complete SD/MMC card

参数

card -- pointer to card information structure previously initialized using sdmmc_card_init

返回

  • ESP_OK on success

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_io_read_byte(sdmmc_card_t *card, uint32_t function, uint32_t reg, uint8_t *out_byte)

Read one byte from an SDIO card using IO_RW_DIRECT (CMD52)

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • function -- IO function number

  • reg -- byte address within IO function

  • out_byte -- [out] output, receives the value read from the card

返回

  • ESP_OK on success

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_io_write_byte(sdmmc_card_t *card, uint32_t function, uint32_t reg, uint8_t in_byte, uint8_t *out_byte)

Write one byte to an SDIO card using IO_RW_DIRECT (CMD52)

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • function -- IO function number

  • reg -- byte address within IO function

  • in_byte -- value to be written

  • out_byte -- [out] if not NULL, receives new byte value read from the card (read-after-write).

返回

  • ESP_OK on success

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_io_read_bytes(sdmmc_card_t *card, uint32_t function, uint32_t addr, void *dst, size_t size)

Read multiple bytes from an SDIO card using IO_RW_EXTENDED (CMD53)

This function performs read operation using CMD53 in byte mode. For block mode, see sdmmc_io_read_blocks.

By default OP Code is set (incrementing address). To send CMD53 without this bit, OR the argument addr with SDMMC_IO_FIXED_ADDR.

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • function -- IO function number

  • addr -- byte address within IO function where reading starts

  • dst -- buffer which receives the data read from card. Aligned to 4 byte boundary unless SDMMC_HOST_FLAG_ALLOC_ALIGNED_BUF flag is set when calling sdmmc_card_init. The flag is mandatory when the buffer is behind the cache.

  • size -- number of bytes to read, 1 to 512.

返回

  • ESP_OK on success

  • ESP_ERR_INVALID_SIZE if size exceeds 512 bytes

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_io_write_bytes(sdmmc_card_t *card, uint32_t function, uint32_t addr, const void *src, size_t size)

Write multiple bytes to an SDIO card using IO_RW_EXTENDED (CMD53)

This function performs write operation using CMD53 in byte mode. For block mode, see sdmmc_io_write_blocks.

By default OP Code is set (incrementing address). To send CMD53 without this bit, OR the argument addr with SDMMC_IO_FIXED_ADDR.

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • function -- IO function number

  • addr -- byte address within IO function where writing starts

  • src -- data to be written. Aligned to 4 byte boundary unless SDMMC_HOST_FLAG_ALLOC_ALIGNED_BUF flag is set when calling sdmmc_card_init. The flag is mandatory when the buffer is behind the cache.

  • size -- number of bytes to write, 1 to 512.

返回

  • ESP_OK on success

  • ESP_ERR_INVALID_SIZE if size exceeds 512 bytes

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_io_read_blocks(sdmmc_card_t *card, uint32_t function, uint32_t addr, void *dst, size_t size)

Read blocks of data from an SDIO card using IO_RW_EXTENDED (CMD53)

This function performs read operation using CMD53 in block mode. For byte mode, see sdmmc_io_read_bytes.

By default OP Code is set (incrementing address). To send CMD53 without this bit, OR the argument addr with SDMMC_IO_FIXED_ADDR.

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • function -- IO function number

  • addr -- byte address within IO function where writing starts

  • dst -- buffer which receives the data read from card. Aligned to 4 byte boundary, and also cache line size if the buffer is behind the cache.

  • size -- number of bytes to read, must be divisible by the card block size.

返回

  • ESP_OK on success

  • ESP_ERR_INVALID_SIZE if size is not divisible by 512 bytes

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_io_write_blocks(sdmmc_card_t *card, uint32_t function, uint32_t addr, const void *src, size_t size)

Write blocks of data to an SDIO card using IO_RW_EXTENDED (CMD53)

This function performs write operation using CMD53 in block mode. For byte mode, see sdmmc_io_write_bytes.

By default OP Code is set (incrementing address). To send CMD53 without this bit, OR the argument addr with SDMMC_IO_FIXED_ADDR.

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • function -- IO function number

  • addr -- byte address within IO function where writing starts

  • src -- data to be written. Aligned to 4 byte boundary, and also cache line size if the buffer is behind the cache.

  • size -- number of bytes to read, must be divisible by the card block size.

返回

  • ESP_OK on success

  • ESP_ERR_INVALID_SIZE if size is not divisible by 512 bytes

  • One of the error codes from SDMMC host controller

esp_err_t sdmmc_io_enable_int(sdmmc_card_t *card)

Enable SDIO interrupt in the SDMMC host

参数

card -- pointer to card information structure previously initialized using sdmmc_card_init

返回

  • ESP_OK on success

  • ESP_ERR_NOT_SUPPORTED if the host controller does not support IO interrupts

esp_err_t sdmmc_io_wait_int(sdmmc_card_t *card, TickType_t timeout_ticks)

Block until an SDIO interrupt is received

Slave uses D1 line to signal interrupt condition to the host. This function can be used to wait for the interrupt.

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • timeout_ticks -- time to wait for the interrupt, in RTOS ticks

返回

  • ESP_OK if the interrupt is received

  • ESP_ERR_NOT_SUPPORTED if the host controller does not support IO interrupts

  • ESP_ERR_TIMEOUT if the interrupt does not happen in timeout_ticks

esp_err_t sdmmc_io_get_cis_data(sdmmc_card_t *card, uint8_t *out_buffer, size_t buffer_size, size_t *inout_cis_size)

Get the data of CIS region of an SDIO card.

You may provide a buffer not sufficient to store all the CIS data. In this case, this function stores as much data into your buffer as possible. Also, this function will try to get and return the size required for you.

参数
  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • out_buffer -- Output buffer of the CIS data

  • buffer_size -- Size of the buffer.

  • inout_cis_size -- Mandatory, pointer to a size, input and output.

    • input: Limitation of maximum searching range, should be 0 or larger than buffer_size. The function searches for CIS_CODE_END until this range. Set to 0 to search infinitely.

    • output: The size required to store all the CIS data, if CIS_CODE_END is found.

返回

  • ESP_OK: on success

  • ESP_ERR_INVALID_RESPONSE: if the card does not (correctly) support CIS.

  • ESP_ERR_INVALID_SIZE: CIS_CODE_END found, but buffer_size is less than required size, which is stored in the inout_cis_size then.

  • ESP_ERR_NOT_FOUND: if the CIS_CODE_END not found. Increase input value of inout_cis_size or set it to 0, if you still want to search for the end; output value of inout_cis_size is invalid in this case.

  • and other error code return from sdmmc_io_read_bytes

esp_err_t sdmmc_io_print_cis_info(uint8_t *buffer, size_t buffer_size, FILE *fp)

Parse and print the CIS information of an SDIO card.

备注

Not all the CIS codes and all kinds of tuples are supported. If you see some unresolved code, you can add the parsing of these code in sdmmc_io.c and contribute to the IDF through the Github repository.

         using sdmmc_card_init

参数
  • buffer -- Buffer to parse

  • buffer_size -- Size of the buffer.

  • fp -- File pointer to print to, set to NULL to print to stdout.

返回

  • ESP_OK: on success

  • ESP_ERR_NOT_SUPPORTED: if the value from the card is not supported to be parsed.

  • ESP_ERR_INVALID_SIZE: if the CIS size fields are not correct.

Macros

SDMMC_IO_FIXED_ADDR

Call sdmmc_io_read_bytes, sdmmc_io_write_bytes, sdmmc_io_read_blocks or sdmmc_io_write_bocks APIs with address ORed by this flag to send CMD53 with OP Code clear (fixed address)

Header File

  • components/esp_driver_sdmmc/include/driver/sdmmc_types.h

  • This header file can be included with:

    #include "driver/sdmmc_types.h"
    
  • This header file is a part of the API provided by the esp_driver_sdmmc component. To declare that your component depends on esp_driver_sdmmc, add the following to your CMakeLists.txt:

    REQUIRES esp_driver_sdmmc
    

    or

    PRIV_REQUIRES esp_driver_sdmmc