This article introduces how to debug card drivers in three ways.Linux SD
1. SD card introduction
SD Card（Secure Digital Memory Card）: The secure digital card is a new generation of high-speed storage device based on semiconductor flash memory.
SDThe card structure is as follows:
The following is a brief summary of the card's external pins, internal registers, speed grade and capacity grade.SD
1. External pin
SDThe card supports three transmission modes: mode, mode and mode.SPI1bit SD4bit SD
In the actual project, I mainly debug the latter two modes. The card has a total of 9 pins, which are summarized as follows:SD
| Pin name | Pin description | Remark |
|---|---|---|
| CLK | clock signal | |
| CMD | command/reply pin | |
| DATE0 ~ 3 | data cable | 1bit SDMode: Use only , : card detection. Mode: :Card Detection/Data 3DATA0CD4bit SDCD/DATA3 |
| VDD | power supply | |
| VSS1/2 | land |
2. Internal register
The SD card related registers are organized as follows:
| Register name | Register description |
|---|---|
| OCR(Operating Conditions Register) | operating condition register |
| CID(Card IDentification Register) | Card identification number register, each card has a unique identification number |
| CSD(Card Specific Data Register) | Describe data register |
| SCR(SD Card Configuration Register) | SD card configuration register |
| RCA(Relative Card Address) | card address register |
| DSR(Driver Stage Register) | driver level register |
3. Speed level
Depending on the data transfer speed, cards have different speed rating representations.SD
| Protocol specifications | Introduction |
|---|---|
| SD1.0 | Used to indicate different speed levels, rarely used.X |
| SD2.0 | Ordinary cards (Class2, Class4, Class6) and high-speed cards (Class10). |
| SD3.0 | Uses UHS speed classes 1 and 3. |
| SD4.0 | Using UHS-II |
4. Capacity level
SDCard capacity currently supports: , and .SDSDHCSDXC
| SD card type | Protocol specifications | Capacity | Supported file formats |
|---|---|---|---|
| SD | SD1.0 | ~2GB | FAT 12,16 |
| SDHC（SD High Capacity） | SD2.0 | 2GB ~ 32GB | FAT 32 |
| SDXC（SD eXtended Capacity） | SD3.0 | 32GB~2TB | exFAT |
2. SD card debugging
1. Schematic diagram
To pre-set the driver, first look at the schematic diagram.
The picture below shows the connection method with the card slot .RK3568microSD
2. SDCard configuration
RK3568 SDCard configuration file:
1）arch/arm64/boot/dts/rockchip/rk3568.dtsi
sdmmc0: dwmmc@fe2b0000 { compatible = "rockchip,rk3568-dw-mshc", "rockchip,rk3288-dw-mshc"; reg = <0x0 0xfe2b0000 0x0 0x4000>; interrupts = <GIC_SPI 98 IRQ_TYPE_LEVEL_HIGH>; max-frequency = <150000000>; clocks = <&cru HCLK_SDMMC0>, <&cru CLK_SDMMC0>, <&cru SCLK_SDMMC0_DRV>, <&cru SCLK_SDMMC0_SAMPLE>; clock-names = "biu", "ciu", "ciu-drive", "ciu-sample"; fifo-depth = <0x100>; resets = <&cru SRST_SDMMC0>; reset-names = "reset"; status = "disabled"; };
2）arch/arm64/boot/dts/rockchip/rk3568-firefly-core.dtsi
&sdmmc0 { max-frequency = <150000000>; supports-sd; bus-width = <4>; cap-mmc-highspeed; cap-sd-highspeed; disable-wp; sd-uhs-sdr104; vmmc-supply = <&vcc3v3_sd>; vqmmc-supply = <&vccio_sd>; pinctrl-names = "default"; pinctrl-0 = <&sdmmc0_bus4 &sdmmc0_clk &sdmmc0_cmd &sdmmc0_det>; status = "okay"; };
in:
clocks: Indicates the card controller clock, and clock.SDdriversample
max-frequency: The maximum operating frequency of the card, adjusted according to different modes.SD
supports-sd: Indicates a card function and must be added. Otherwise the card cannot be initialized.SDSD
bus-width: The card uses 4-wire mode. If not configured, the default is 1-wire mode.SD
cap-mmc-highspeed/cap-sd-highspeed:Supported cards .highspeedSD
vmmc-supply、vqmmc-supply: Card power domain.SD
SD3.0Speed mode:
sd-uhs-sdr12: clock frequency does not exceed 24M, signal voltage 1.8V sd-uhs-sdr25: clock frequency does not exceed 50M, signal voltage 1.8V sd-uhs-sdr50: clock frequency does not exceed 100M, signal voltage 1.8V sd- uhs-ddr50: clock frequency does not exceed 50M, uses double-edge sampling, signal voltage 1.8V sd-uhs-sdr104: clock frequency does not exceed 208M, signal voltage 1.8V
pinctrl-0: Card configuration.SDpinmux
3. SDCard driver
RK3568Driver file: , mainly focus on:drivers/mmc/host/dw_mmc-rockchip.c
static const struct dw_mci_drv_data rk3288_drv_data = { .caps = dw_mci_rk3288_dwmmc_caps, .num_caps = ARRAY_SIZE(dw_mci_rk3288_dwmmc_caps), .set_ios = dw_mci_rk3288_set_ios, ## Configure clock, total Line, power supply, chip select, timing, etc. execute_tuning = dw_mci_rk3288_execute_tuning, ## Adjust driver clk and sample clk phase .parse_dt = dw_mci_rk3288_parse_dt, .init = dw_mci_rockchip_init, };
RK3568 SDController usage , mainly focus on: and .Synopsys IPdw_mci_rk3288_set_ios（）dw_mci_rk3288_execute_tuning（）
After the system starts, you can view the card properties through the following command (driver implementation: ):SDdrivers/mmc/core/debugfs.c
[root@xiaotianbsp:/]# cat /sys/kernel/debug/mmc1/ios clock: 150000000 Hz actual clock: 148500000 Hz vdd: 21 (3.3 ~ 3.4 V) bus mode: 2 (push-pull) chip select: 0 (don't care) power mode: 2 (on) bus width: 2 (4 bits) timing spec: 6 (sd uhs SDR104) signal voltage: 1 (1.80 V) driver type: 0 (driver type B)
3. SDCard test
The following test is completed based on the card.SanDisk Ultra 1 32G SD
1. SD card detection
After the system starts, the card startup log is as follows:SD
[ 1.225398] dwmmc_rockchip fe2b0000.dwmmc: Successfully tuned phase to 266 [ 1.225420] mmc1: new ultra high speed SDR104 SDHC card at address aaaa [ 1.226456] mmcblk1: mmc1:aaaa SD32G 29.7 GiB [ 1.227643] mmcblk1: p1
If the card is not initialized normally, the following log will appear:SD
[ 182.501273] mmc_host mmc1: Bus speed (slot 0) = 375000Hz (slot req 400000Hz, actual 375000HZ div = 0) [ 182.672282] mmc1: error -123 whilst initialising SD card [ 182.686489] mmc_host mmc1: Bus speed (slot 0) = 375000Hz (slot req 300000Hz, actual 187500HZ div = 1) [ 182.699318] mmc_host mmc1: Bus speed (slot 0) = 375000Hz (slot req 375000Hz, actual 375000HZ div = 0) [ 182.717513] mmc_host mmc1: Bus speed (slot 0) = 375000Hz (slot req 200000Hz, actual 187500HZ div = 1)
Reason: Failure. Error message definition ( ):mmc_sd_init_card()include/uapi/asm-generic/errno.h
#define ETIMEDOUT 110 /* Connection timed out */ ... #define ENOMEDIUM 123 /* No medium found */
2. SD card register
Through the following command, you can view the values of card-related registers.SD
[root@xiaotianbsp:/]# cd /sys/class/mmc_host/mmc1/mmc1:aaaa [root@xiaotianbsp:/sys/devices/platform/fe2b0000.dwmmc/mmc_host/mmc1/mmc1:aaaa]# ls block driver hwrev oemid scr type cid dsr manfid power serial uevent csd erase_size name preferred_erase_size ssr date fwrev ocr rca subsystem [root@xiaotianbsp:/sys/devices/platform/fe2b0000.dwmmc/mmc_host/mmc1/mmc1:aaaa]# cat cid 03534453443332478554c 496d501636f ## Others The register viewing method is similar to
SDThe method to view other parameters of the card is as follows:
[root@xiaotianbsp:/sys/devices/platform/fe2b0000.dwmmc/mmc_host/mmc1/mmc1:aaaa]# cat erase_size 512 [root@xiaotianbsp:/sys/devices/platform/fe2b0000.dwmmc/mmc_host/mmc1/mmc1:aaaa]# cat fwrev 0x5 [root@xiaotianbsp:/sys/devices/platform/fe2b0000.dwmmc/mmc_host/mmc1/mmc1:aaaa]# cat hwrev 0x8 [root@xiaotianbsp:/sys/devices/platform/fe2b0000.dwmmc/mmc_host/mmc1/mmc1:aaaa]# cat manfid 0x000003 [root@xiaotianbsp:/sys/devices/platform/fe2b0000.dwmmc/mmc_host/mmc1/mmc1:aaaa]# cat name SD32G [root@xiaotianbsp:/sys/devices/platform/fe2b0000.dwmmc/mmc_host/mmc1/mmc1:aaaa]# cat oemid 0x5344 [root@xiaotianbsp:/sys/devices/platform/fe2b0000.dwmmc/mmc_host/mmc1/mmc1:aaaa]# cat serial 0x54c496d5 [root@xiaotianbsp:/sys/devices/platform/fe2b0000.dwmmc/mmc_host/mmc1/mmc1:aaaa]# cat type SD
3. Mount/unmount
SDCard partition mounting command:
[root@xiaotianbsp:/]# mount -t vfat /dev/mmcblk1p1 /tmp/ [ 244.746983] FAT-fs (mmcblk1p1): utf8 is not a recommended IO charset for FAT filesystems, filesystem will be case sensitive! [ 244.749331] FAT-fs (mmcblk1p1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck. [root@xiaotianbsp:/]# mount ... /dev/mmcblk1p1 on /tmp type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=936,iocharset=utf8,shortname=mixed,errors=remount-ro)
SDCard partition uninstall command:
umount /dev/mmcblk1p1
4. Create partitions
Partitions can be recreated on the card using the command.fdiskSD
[root@xiaotianbsp:/]# fdisk /dev/mmcblk1 ... Command (m for help): p ## 1. View the existing partition Disk /dev/mmcblk1: 30 GB, 31914983424 bytes, 62333952 sectors 3880 cylinders, 255 heads, 63 sectors/track Units: cylinders of 16065 * 512 = 8225280 bytesDevice Boot StartCHS EndCHS StartLBA EndLBA Sectors Size Id Type /dev/mmcblk1p1 0,0,17 1023,254,63 16 62333951 62333936 29.7G c Win95 FAT32 ( LBA) Command (m for help): d ## 2. Delete the partition Selected partition 1 Command (m for help): p Disk /dev/mmcblk1: 30 GB, 31914983424 bytes, 62333952 sectors 3880 cylinders, 255 heads, 63 sectors/track Units: cylinders of 16065 * 512 = 8225280 bytesDevice Boot StartCHS EndCHS StartLBA EndLBA Sectors Size Id TypeCommand ( m for help): n ## 3. Create a new partition, a total of 2 partitions are createdCommand action e extended p primary partition (1-4) p Partition number (1-4): 1 First cylinder (1-3880, default 1): Using default value 1 Last cylinder or +size or +sizeM or +sizeK (1-3880, default 3880): 1940 Command (m for help): p Disk /dev/mmcblk1: 30 GB, 31914983424 bytes, 62333952 sectors 3880 cylinders, 255 heads, 63 sectors/track Units: cylinders of 16065 * 512 = 8225280 bytes Device Boot StartCHS EndCHS StartLBA EndLBA Sectors Size Id Type /dev/mmcblk1p1 0,1,1 1023,254,63 63 31166099 31166037 14.8G 83 Linux Command (m for help): n Command action e extended p primary partition (1-4 ) p Partition number (1-4): 2 First cylinder (1941-3880, default 1941): Using default value 1941 Last cylinder or +size or +sizeM or +sizeK (1941-3880, default 3880): Using default value 3880 Command (m for help): p Disk /dev/mmcblk1: 30 GB, 31914983424 bytes, 62333952 sectors 3880 cylinders, 255 heads, 63 sectors/track Units: cylinders of 16065 * 512 = 8225280 bytes Device Boot StartCHS EndCHS StartLBA EndLBA Sectors Size Id Type /dev/mmcblk1p1 0,1,1 1023,254,63 63 31166099 31166037 14.8G 83 Linux /dev/mmcblk1p2 1023,254,63 1023,254,63 31166100 62332199 3116 6100 14.8G 83 Linux Command (m for help): w ## 4. Save the new partition
5. Reading and writing test
Test card writing command:SD
[root@RK356X:/]# time dd oflag=direct,nonblock if=/dev/zero of=/dev/mmcblk1p1 bs=1M count=100 100+0 records in 100+0 records out 104857600 bytes (105 MB, 100 MiB) copied, 3.4844 s, 30.1 MB/s real 0m 3.49s user 0m 0.00s sys 0m 0.16s
Test card reading command:SD
[root@RK356X:/]# time dd iflag=direct,nonblock if=/dev/mmcblk1p1 of=/dev/null bs=1M count=100 100+0 records in 100+0 records out 104857600 bytes (105 MB, 100 MiB) copied, 1.65236 s, 63.5 MB/s real 0m 1.65s user 0m 0.00s sys 0m 0.03s
The and attributes configured in the above command can avoid the file system and read and write directly without using them .iflagoflagcachebuffer cache
Note: Please indicate the author and source when reprinting.
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