SDIO (SD Card)
Helios4 SoC (Armada 388) SDIO controller supports up to UHS-I speed mode.
Following modes are supported:
- Default Speed (DS)–up to 25 MHz, 1.8V/3.3V signaling
- High Speed (HS)–up to 50 MHz, 1.8V/3.3V signaling
- SDR12–SDR up to 25 MHz, 1.8V/3.3V signaling
- SDR25–SDR up to 50 MHz, 1.8V/3.3V signaling
- SDR50–SDR up to 100 MHz, 1.8V signaling
- DDR50–DDR up to 50 MHz, 1.8V/3.3V signaling
However, it is not compatible with all cards even though the SD cards are declared as UHS-I capable. To keep it compatible with most of card, Helios4 device tree only define by default Normal Speed mode.
Warning
Enabling High Speed and UHS-I support could lead to unbootable system because of incompatible microSD card.
Important
From Linux Kernel 4.19 onwards, High Speed and UHS-I modes for Helios4 do NOT work. It requires further work on our side.
Device Tree Modification¶
To enable High Speed mode and UHS-I support, Helios4 device tree need to be modified. The following instructions are executed under Helios4.
Prerequisites¶
- Helios4 Linux Kernel Source Code
- Build Essentials package
Install the dependencies and extract the source into ~/src/linux
sudo apt-get -y install build-essential linux-source-4.14.87-next-mvebu
mkdir -p ~/src/linux
tar Jxf /usr/src/linux-source-$(uname -r).tar.xz -C ~/src/linux
Note
You will need to choose the right linux-source package that matches the kernel version you are running. Check kernel version with command uname -r.
Patching and Compilation¶
Download and apply this patch to Linux kernel source code.
cd ~/src/linux
wget https://wiki.kobol.io/helios4/files/sdcard/helios4_dtb_sd_uhs_linux_stable.patch
git apply --apply --verbose helios4_dtb_sd_uhs_linux_stable.patch
Compile the device tree into dtb
cp /boot/config-$(uname -r) .config
make armada-388-helios4.dtb
cp arch/arm/boot/dts/armada-388-helios4.dtb armada-388-helios4.dtb.uhs
Info
Precompiled dtb for Linux kernel 4.14 can be found here
Copy new dtb to /boot/dtb/, backup the original dtb and create symlink to new dtb
sudo cp armada-388-helios4.dtb.uhs /boot/dtb/
cd /boot/dtb/
sudo cp armada-388-helios4.dtb armada-388-helios4.dtb.ori
sudo ln -sf armada-388-helios4.dtb.uhs armada-388-helios4.dtb
Reboot the system.
Recovery¶
If the system become unbootable after applying modified dtb, recover the system by connecting to Helios4 serial console and run following commands
setenv fdt_addr 0x2040000
setenv bootargs "console=ttyS0,115200 root=/dev/mmcblk0p1 rootwait rootfstype=ext4 ubootdev=mmc scandelay ignore_loglevel"
load mmc 0:1 ${fdt_addr} /boot/dtb/armada-388-helios4.dtb.ori
load mmc 0:1 ${ramdisk_addr_r} /boot/uInitrd
load mmc 0:1 ${kernel_addr_r} /boot/zImage
setenv fdt_high 0xffffffff
setenv initrd_high 0xffffffff
bootz ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr}
After successfully boot to Linux, restore the original dtb and remove the modified one.
sudo mv -f /boot/dtb/armada-388-helios4.dtb.ori /boot/dtb/armada-388-helios4.dtb
sudo rm /boot/dtb/armada-388-helios4.dtb.uhs
Performance Testing¶
The test methodology is adapted from SD card performance - Research guides & tutorials - Armbian forum with slightly modified parameter to run the test on SD card mounted under /mnt/sdcard.
iozone -e -I -a -s 100M -r 4k -r 16k -r 512k -r 1024k -r 16384k -i 0 -i 1 -i 2 -f /mnt/sdcard/iozone-test.dat
To automate the test, a test script named run_sdcard_test.sh was created.
Test Procedure¶
1. Prepare the system to boot from SPI and Rootfs located on USB drive. See SPI (NOR Flash) page.
2. Build and replace Helios4 dtb as instructed in Device Tree Modification.
3. Install iozone and download the test script
sudo apt-get -y install iozone3
wget https://wiki.kobol.io/helios4/files/sdcard/run_sdcard_test.sh
chmod 755 run_sdcard_test.sh
4. Override kernel loglevel on every boot
sudo sed -i 's/^exit 0/dmesg -n 8\nexit 0/g' /etc/rc.local
5. Make sure armada-388-helios4.dtb points to armada-388-helios4.dtb.uhs
cd /boot/dtb/
sudo ln -sf armada-388-helios4.dtb.uhs armada-388-helios4.dtb
6. Reboot and cancel U-Boot autoboot.
7. Read SD card info and boot to Linux
mmc rescan
mmc info
bootd
8. Observe whether any error/warning on sd card detection in console and check whether sdcard is detected.
dmesg | grep "mmc"
lsblk
9. Run the test script
sudo ./run_sdcard_test.sh
The test script will display the test progress and log result into log file : SD_test_<sdcard_address>_[<sdcard_name>]_<date_in_YYYYMMDD_HHMMSS>.log
Example filename: SD_test_mmc0:aaaa-[SU08G]_20181212_034241.log
If the SD card is not detected, the test script would exit without saving any log file.
10. Change armada-388-helios4.dtb to point back to armada-388-helios4.dtb.ori
cd /boot/dtb/
sudo ln -sf armada-388-helios4.dtb.ori armada-388-helios4.dtb
11. Repeat step 6 until 9 to test in Normal Speed mode.
12. Repeat step 5 until 11 for other card.
13. Remove kernel loglevel override done in step 4.
sudo sed -i '/^dmesg -n 8/d' /etc/rc.local
Tested MicroSD Card¶
Below a non-exhaustive list of microSD Card models that we tested to check compatibility with UHS-I speed mode. We will keep populating this list with new microSD Card models.
| MicroSD Card Model | UHS-I Compatibility Result |
|---|---|
| Kingston Mobile Card microSDHC (16GB) | not compatible |
| Samsung microSDHC UHS-I Card EVO Plus (32GB) | yes, but no performance improvement if used as boot drive |
| SanDisk Extreme microSDHC UHS-I Card (32GB) | yes, performance boosted |
| SanDisk Extreme PRO microSDHC UHS-I Card (32GB) | yes, performance boosted |
| SanDisk Ultra microSD UHS-I Card (32GB) | yes, but no performance improvement |
| SanDisk Ultra microSD UHS-I Card (16GB) | not compatible |
| SanDisk Ultra microSD UHS-I Card 48MBps (16GB) | not compatible |
| SanDisk Ultra microSD UHS-I Card 30MBps (8GB) | yes, but no performance improvement |
| Strontium Nitro MicroSD Card (16GB) | yes, performance boosted |
| Toshiba MicroSD Exceria Pro (16GB) | not compatible |
| Transcend microSDHC Premium (8GB) | yes, but no performance improvement |
Kingston Mobile Card microSDHC (16GB)¶
Specifications
| Product Page | https://www.kingston.com/en/flash/microsd_cards/sdc10g2 |
| Manufacture Id | 0x00009f |
| OEM ID | 0x5449 |
| Product Name | SD16G |
| HW Revision | 0x3 |
| FW Revision | 0x0 |
| Serial Number | 0x5b3003c7 |
| Manufacture Date | 07/2018 |
| Capacity Standard | SDHC |
| SD version* | 1.0 |
| Mode* | SD Legacy |
| Bus Speed* | 25000000 |
| Bus Width* | 4-bit |
Notes
- Value taken from U-Boot "mmc info".
Test Result : Failed!
mmc0: new SDHC card at address 0001
mmcblk0: mmc0:0001 SD16G 14.6 GiB
mmcblk0: p1
The card was detected by Linux but when the test runnning, kernel console constantly emits
mmcblk0: error -110 transferring data, sector 2433024, nr 1024, cmd response 0x900, card status 0xb00
mmcblk0: retrying using single block read
mmc0: Timeout waiting for hardware interrupt.
mmc0: sdhci: ============ SDHCI REGISTER DUMP ===========
mmc0: sdhci: Sys addr: 0x00000000 | Version: 0x00000202
mmc0: sdhci: Blk size: 0x00007200 | Blk cnt: 0x00000030
mmc0: sdhci: Argument: 0x00252400 | Trn mode: 0x00000033
mmc0: sdhci: Present: 0x01e70206 | Host ctl: 0x00000011
mmc0: sdhci: Power: 0x0000000f | Blk gap: 0x00000000
mmc0: sdhci: Wake-up: 0x00000000 | Clock: 0x0000fa07
mmc0: sdhci: Timeout: 0x00000003 | Int stat: 0x00000000
mmc0: sdhci: Int enab: 0x02ff008b | Sig enab: 0x02ff008b
mmc0: sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
mmc0: sdhci: Caps: 0x25fcc8b2 | Caps_1: 0x00002f77
mmc0: sdhci: Cmd: 0x0000123a | Max curr: 0x00000000
mmc0: sdhci: Resp[0]: 0x00000900 | Resp[1]: 0x47305b30
mmc0: sdhci: Resp[2]: 0x53443136 | Resp[3]: 0x009f5449
mmc0: sdhci: Host ctl2: 0x00000008
mmc0: sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x7f0b95d0
mmc0: sdhci: ============================================
mmcblk0: error -110 transferring data, sector 2434048, nr 1024, cmd response 0x900, card status 0xb00
mmc0: Timeout waiting for hardware interrupt.
And the still did not finished the test after 8 hours.
Samsung microSDHC UHS-I Card EVO Plus (32GB)¶
Specifications
| Product Page | https://www.samsung.com/us/computing/memory-storage/memory-cards/microsdhc-evo-plus-memory-card-w--adapter-32gb--2017-model--mb-mc32ga-am/ |
| Manufacture Id | 0x00001b |
| OEM ID | 0x534d |
| Product Name | EB1QT |
| HW Revision | 0x3 |
| FW Revision | 0x0 |
| Serial Number | 0x6d4061eb |
| Manufacture Date | 06/2018 |
| Capacity Standard | SDHC |
| SD version* | 3.0 |
| Mode* | SD High Speed (50MHz) |
| Bus Speed* | 50000000 |
| Bus Width* | 4-bit |
Notes
- Value taken from U-Boot "mmc info".
Test Result
[ 3.428116] mmc0: new high speed SDHC card at address 0001
[ 3.434040] mmcblk0: mmc0:0001 EB1QT 29.8 GiB
[ 3.517590] mmcblk0: p1
[ 48.452996] mmc0: card 0001 removed
[ 50.155681] mmc0: new ultra high speed DDR50 SDHC card at address 0001
[ 50.162494] mmcblk0: mmc0:0001 EB1QT 29.8 GiB
[ 50.169200] mmcblk0: p1
Card speed stays at high speed during boot up while other UHS-I compatible card switched to ultra high speed. It only changed to ultra high speed after remove and reinsert the card.
If the card is used as boot/system drive, it is not allowed to be removed during runtime therefore no performance gain since the speed stays at high speed.
SanDisk Extreme microSDHC UHS-I Card (32GB)¶
Specifications
| Product Page | https://www.sandisk.com/home/memory-cards/microsd-cards/extreme-microsd |
| Manufacture Id | 0x000003 |
| OEM ID | 0x5344 |
| Product Name | SM32G |
| HW Revision | 0x8 |
| FW Revision | 0x0 |
| Serial Number | 0x4313d13b |
| Manufacture Date | 10/2018 |
| Capacity Standard | SDHC |
| SD version* | 3.0 |
| Mode* | SD High Speed (50MHz) |
| Bus Speed* | 50000000 |
| Bus Width* | 4-bit |
Notes
- Value taken from U-Boot "mmc info".
Test Result
mmc0: new ultra high speed DDR50 SDHC card at address aaaa
mmcblk0: mmc0:aaaa SM32G 29.7 GiB
mmcblk0: p1
SanDisk Extreme PRO microSDHC UHS-I Card (32GB)¶
Specifications
| Product Page | https://www.sandisk.com/home/memory-cards/microsd-cards/extremepro-microsd |
| Manufacture Id | 0x000003 |
| OEM ID | 0x5344 |
| Product Name | SP32G |
| HW Revision | 0x8 |
| FW Revision | 0x0 |
| Serial Number | 0x122a8270 |
| Manufacture Date | 10/2017 |
| Capacity Standard | SDHC |
| SD version* | 3.0 |
| Mode* | SD High Speed (50MHz) |
| Bus Speed* | 50000000 |
| Bus Width* | 4-bit |
Notes
- Value taken from U-Boot "mmc info".
Test Result
mmc0: new ultra high speed DDR50 SDHC card at address e624
mmcblk0: mmc0:e624 SP32G 29.7 GiB
mmcblk0: p1
SanDisk Ultra microSD UHS-I Card (32GB)¶
Specifications
| Product Page | https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-for-smartphones |
| Manufacture Id | 0x000003 |
| OEM ID | 0x5344 |
| Product Name | SL32G |
| HW Revision | 0x8 |
| FW Revision | 0x0 |
| Serial Number | 0x0c9daa71 |
| Manufacture Date | 04/2014 |
| Capacity Standard | SDHC |
| SD version* | 3.0 |
| Mode* | SD High Speed (50MHz) |
| Bus Speed* | 50000000 |
| Bus Width* | 4-bit |
Notes
- Value taken from U-Boot "mmc info".
Test Result
mmc0: new ultra high speed DDR50 SDHC card at address aaaa
mmcblk0: mmc0:aaaa SL32G 29.7 GiB
mmcblk0: p1
mmc0: Tuning failed, falling back to fixed sampling clock
mmcblk0: error -84 transferring data, sector 62333824, nr 8, cmd response 0x900, card status 0xb00
Even though there are some errors, the test finished without much improvement.
SanDisk Ultra microSD UHS-I Card (16GB)¶
Specifications
| Product Page | https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-for-smartphones |
| Manufacture Id | 0x000003 |
| OEM ID | 0x5344 |
| Product Name | SL16G |
| HW Revision | 0x8 |
| FW Revision | 0x0 |
| Serial Number | 0xa5253c77 |
| Manufacture Date | 04/2017 |
| Capacity Standard | SDHC |
| SD version* | 3.0 |
| Mode* | SD High Speed (50MHz) |
| Bus Speed* | 50000000 |
| Bus Width* | 4-bit |
Notes
- Value taken from U-Boot "mmc info".
Test Result : Failed!
mmc0: new ultra high speed DDR50 SDHC card at address aaaa
mmcblk0: mmc0:aaaa SL16G 14.8 GiB
mmcblk0: error -84 sending status command, retrying
mmc0: Tuning failed, falling back to fixed sampling clock
mmcblk0: error -84 sending status command, retrying
mmc0: Tuning failed, falling back to fixed sampling clock
mmcblk0: error -84 sending status command, aborting
mmc0: Tuning failed, falling back to fixed sampling clock
mmcblk0: unable to read partition table
mmc0: card aaaa removed
mmc0: new high speed SDHC card at address aaaa
mmcblk0: mmc0:aaaa SL16G 14.8 GiB
mmcblk0: error -84 sending status command, retrying
mmcblk0: error -84 sending stop command, original cmd response 0x900, card status 0x900
mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0x0
mmcblk0: error -84 sending stop command, original cmd response 0x900, card status 0x900
mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0x0
The card was not detected by Linux.
SanDisk Ultra microSD UHS-I Card 48MBps (16GB)¶
Specifications
| Product Page | https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-48mbs |
| Manufacture Id | 0x000003 |
| OEM ID | 0x5344 |
| Product Name | SL16G |
| HW Revision | 0x8 |
| FW Revision | 0x0 |
| Serial Number | 0x349f2b91 |
| Manufacture Date | 01/2016 |
| Capacity Standard | SDHC |
| SD version* | 3.0 |
| Mode* | SD High Speed (50MHz) |
| Bus Speed* | 50000000 |
| Bus Width* | 4-bit |
Notes
- Value taken from U-Boot "mmc info".
Test Result : Failed!
mmc0: new ultra high speed DDR50 SDHC card at address aaaa
mmcblk0: mmc0:aaaa SL16G 14.8 GiB
mmc0: Tuning failed, falling back to fixed sampling clock
mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0xb00
mmcblk0: p1
mmcblk0: error -84 transferring data, sector 10240, nr 8, cmd response 0x900, card status 0xb00
mmcblk0: error -84 transferring data, sector 8784, nr 72, cmd response 0x900, card status 0xb00
mmcblk0: error -84 transferring data, sector 8784, nr 72, cmd response 0x900, card status 0xb00
mmcblk0: retrying using single block read
mmcblk0: error -84 transferring data, sector 8856, nr 360, cmd response 0x900, card status 0xb00
mmcblk0: error -84 transferring data, sector 8856, nr 360, cmd response 0x900, card status 0xb00
The card was not detected by Linux.
SanDisk Ultra microSD UHS-I Card 30MBps (8GB)¶
Specifications
| Product Page | https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-for-smartphones |
| Manufacture Id | 0x000003 |
| OEM ID | 0x5344 |
| Product Name | SU08G |
| HW Revision | 0x8 |
| FW Revision | 0x0 |
| Serial Number | 0x2369e07f |
| Manufacture Date | 12/2013 |
| Capacity Standard | SDHC |
| SD version* | 3.0 |
| Mode* | SD High Speed (50MHz) |
| Bus Speed* | 50000000 |
| Bus Width* | 4-bit |
Notes
- Value taken from U-Boot "mmc info".
Test Result
mmc0: new ultra high speed DDR50 SDHC card at address aaaa
mmcblk0: mmc0:aaaa SU08G 7.40 GiB
mmc0: Tuning failed, falling back to fixed sampling clock
mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0xb00
mmcblk0: p1
Even though there are some errors, the test finished. Many of test cases see performance reduction.
Strontium Nitro MicroSD Card (16GB)¶
Specifications
| Product Page | http://www.strontium.biz/products/memory-cards/mobile-memory-cards/#seven |
| Manufacture Id | 0x000084 |
| OEM ID | 0x5446 |
| Product Name | SD |
| HW Revision | 0x0 |
| FW Revision | 0x0 |
| Serial Number | 0x954b266b |
| Manufacture Date | 09/2016 |
| Capacity Standard | SDHC |
| SD version* | 3.0 |
| Mode* | SD High Speed (50MHz) |
| Bus Speed* | 50000000 |
| Bus Width* | 1-bit |
Notes
- Value taken from U-Boot "mmc info".
Test Result
mmc0: Tuning failed, falling back to fixed sampling clock
mmc0: new ultra high speed DDR50 SDHC card at address 0001
mmcblk0: mmc0:0001 SD 14.6 GiB
mmcblk0: p1
mmc0: Tuning failed, falling back to fixed sampling clock
mmc0: Tuning failed, falling back to fixed sampling clock
Even though there are some warnings, the test finished.
Toshiba MicroSD Exceria Pro (16GB)¶
Specifications
| Product Page | https://www.toshiba-memory.com/products/toshiba-microsd-cards-exceria-pro-m401/ |
| Manufacture Id | 0x000002 |
| OEM ID | 0x544d |
| Product Name | UC0C5 |
| HW Revision | 0x5 |
| FW Revision | 0x0 |
| Serial Number | 0xd2a0e6a3 |
| Manufacture Date | 11/2016 |
| Capacity Standard | SDHC |
| SD version* | 3.0 |
| Mode* | SD High Speed (50MHz) |
| Bus Speed* | 50000000 |
| Bus Width* | 4-bit |
Notes
- Value taken from U-Boot "mmc info".
Test Result : Failed!
mmc0: error -84 whilst initialising SD card
The card was not detected by Linux.
Transcend microSDHC Premium (8GB)¶
Specifications
| Product Page | https://www.transcend-info.com/Products/No-320 |
| Manufacture Id | 0x000074 |
| OEM ID | 0x4a45 |
| Product Name | USD |
| HW Revision | 0x1 |
| FW Revision | 0x0 |
| Serial Number | 0x4568e585 |
| Manufacture Date | 06/2014 |
| Capacity Standard | SDHC |
| SD version* | 3.0 |
| Mode* | SD High Speed (50MHz) |
| Bus Speed* | 50000000 |
| Bus Width* | 1-bit |
Test Result
mmc0: new high speed SDHC card at address b368
mmcblk0: mmc0:b368 USD 7.45 GiB
mmcblk0: p1
*Value taken from U-Boot "mmc info"