SDIO Development Guide
ID: RK-KF-YF-102
Release Version: V1.2.0
Date: 2020-06-28
Security Level: □Top-Secret □Secret □Internal ■Public
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Due to product version upgrades or other reasons, this document may be updated or modified from time to time without any notice.
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Preface
Overview
Product Versions
| Chip Name | RT Thread Version |
|---|---|
| All chips using RT Thread |
Intended Audience
This document (guide) is mainly applicable to the following engineers: Technical support engineers Software development engineers
Revision History
| Version | Author | Date | Description |
|---|---|---|---|
| V1.0.0 | Lin Tao | 2019-07-11 | Initial release |
| V1.0.1 | Lin Tao | 2019-09-03 | Updated file path |
| V1.0.2 | Lin Tao | 2020-02-21 | Updated disk mounting |
| V1.1.0 | Lin Tao | 2020-03-13 | Updated format operation |
| V1.2.0 | Lin Tao | 2020-06-28 | Added board-level configuration |
[TOC]
RT-Thread Rockchip SDIO Features
SDIO (Secure Digital Input and Output)
- Compatible with SDIO/SD card/eMMC
- Only supports Highspeed mode, 1/4/8 bus widths
- Supports DMA transfer mode
Software
Code Paths
SDIO framework:
components/drivers/include/drivers/mmcsd_*.h
components/drivers/sdio/block_dev.c SD card, eMMC and RTT block layer interface code
components/drivers/sdio/mmcsd_core.c SD card, SDIO, eMMC protocol stack common code
components/drivers/sdio/sdio.c SDIO protocol stack
components/drivers/sdio/sd.c SD card protocol stack
components/drivers/sdio/mmc.c eMMC protocol stack
SDIO driver adaptation layer:
bsp/rockchip/common/drivers/drv_sdio.c
bsp/rockchip/common/drivers/drv_sdio.h
Configuration
Enable SDIO configuration. For SD cards and eMMC, the /dev/sdioX device will be generated. For SDIO devices, the corresponding wifi driver node will appear only after the SDIO function driver (e.g., wifi driver) calls sdio_register_driver.
RT-Thread bsp drivers --->
RT-Thread rockchip common drivers --->
[*] Enable SDIO
RT-Thread components --->
Device Drivers --->
[*] Using SD/MMC device drivers
(512) The stack size for sdio irq thread
(15) The priority level value of sdio irq thread
(1024) The stack size for mmcsd thread
(22) The priority level value of mmcsd thread
(16) mmcsd max partition
[ ] Enable SDIO debug log output
To modify the bus width or communication frequency, adjust settings in the board-level file. freq_max is the maximum operating frequency and must not be configured higher than 50MHz. flags indicates the supported modes. To support 8-bit width, change to MMCSD_BUSWIDTH_8. If only 1-bit width is needed, remove the MMCSD_BUSWIDTH_4 attribute.
RT_WEAK struct rk_mmc_platform_data rk_mmc_table[] =
{
#ifdef RT_USING_SDIO0
{
.flags = MMCSD_BUSWIDTH_4 | MMCSD_MUTBLKWRITE | MMCSD_SUP_SDIO_IRQ | MMCSD_SUP_HIGHSPEED,
.irq = SDIO_IRQn,
.base = SDIO_BASE,
.clk_id = CLK_SDIO_PLL,
.freq_min = 100000,
.freq_max = 50000000,
.control_id = 0,
},
#endif
Execute the command to see the generated serial device:
msh >list_device
device type ref count
------ -------------------- ----------
sd0 Block Device 0
sd1 Block Device 0
Debugging
- Enabling the RT_SDIO_DEBUG configuration will output more execution flow information of the SDIO/SD/EMMC protocol stack.
- Enabling RK_MMC_DBG in bsp/rockchip-common/drivers/drv_sdio.c will output more controller driver execution information.
- Ensure that the IOMUX, IO power supply, card power supply, and corresponding gpio bank io domain are configured correctly in the board-level configuration, and that the controller's output clock is obtained by even division.
- If the wifi driver has multiple threads reading/writing to the function simultaneously, use the mmcsd_host_lock and mmcsd_host_unlock interfaces for mutual exclusion protection.
EMMC or SD Card Mounting
(1) Enable DFS support and elmfatfs file system format support.
(2) Enter list_device in the shell to see that the SD Card or EMMC has been registered as a block device.
(3) Configure the mount format and path in the mnt.c file in each board-level directory. Taking RK2108b as an example, mount the sd0 block device with elm file system format to the "/sdcard" directory.
bsp/rockchip/rk2108/board/rk2108b_evb/mnt.c
const struct dfs_mount_tbl mount_table[] = {
{PARTITION_ROOT, "/", "elm", 0, 0},
+ {"sd0", "/sdcard", "elm", 0, 0},
};
(4) If the eMMC component or SD card has not been formatted, the following log will appear after boot:
In this case, enable the RT_USING_DEVICE_OPS macro in the config configuration items and perform formatting. Taking formatting the sd0 block device with a fat partition (i.e., elm) as an example, execute mkfs -t elm sd0 in the shell, then restart the device to complete mounting.
(5) If the following abnormal log appears: "There is no space to mount this file system" Modify the DFS_FILESYSTEMS_MAX limit in the config configuration items; try adjusting it to 3 or higher.
RT-Thread components --->
Device virtual file system --->
(2) The maximal number of mounted file system