This version (24 Jul 2020 11:06) was approved by Sunny Feng.
Table of Contents
Mobile Storage Interface for MMC/SD
The ADSP-SC5xx processors provide a mobile storage interface (MSI). MSI is a fast, synchronous controller that uses various protocols to communicate with MMC, SD, and SDIO cards to address the growing storage need in embedded systems, handheld and consumer electronics applications requiring low power. The MSI is compatible with the following protocols.
- MMC (Multimedia Card) bus protocol
- SD (Secure Digital) bus protocol
- SDIO (Secure Digital Input Output) bus protocol
All of these storage solutions use similar interface protocols. The main difference between MMC and SD support is the initialization sequence. The main difference between SD and SDIO support is the use of interrupt and read wait signals for SDIO.
Hardware Setup
An ADSP-SC5xx EZ-Board:
- ADSP-SC589 Ezkit v1.1 and above, or,
- ADSP-SC573 Ezkit v1.2 (BOM 1.8) and above or,
- ADSP-SC589 MINI v1.3 and above
- SC584 processor does not include MMC/SD controller
The SD/MMC card slot is J18 on the SC589/SC573 EZKIT board and is J6 on the SC589 MINI board. This slot accepts full-size SD and MMC cards, or microSD cards with an adapter.
Software Configuration
Package Configuration
Add Bonnie++ package in the filesystem. Bonnie++ is a program for testing filesystem throughput, see www.coker.com.au/bonnie++ for details.
vim build/conf/local.conf IMAGE_INSTALL_append = " dosfstools e2fsprogs bonnie++"
Configure Linux Kernel
Run “bitbake linux-adi -c menuconfig” to configure the linux kernel.
Enable MSI Support
Device Drivers MMC/SD/SDIO card support ---> <*> Synopsys DesignWare Memory Card Interface -*- Synopsys Designware MCI Support as platform device <*> ADI specific extensions for Synopsys DW Memory Card Interface
File System Support
If you want to mount an SD card in a particular format, you should compile the Linux kernel with the corresponding file-system first.
Example1：FAT32 SD card, corresponding filesystem is VFAT. Configuration is shown below:
File systems --->
DOS/FAT/NT Filesystems --->
[*] VFAT (Windows-95) fs support
(437) Default codepage for FAT
(iso8859-1) Default iocharset for FAT
Example2: ext2 SD card, corresponding filesystem is ext2. Configuration is shown below:
File systems ---> <*> Second extended fs support [*] Ext2 extended attributes [*] Ext2 POSIX Access Control Lists [*] Ext2 Security Labels
Build and Load Linux Kernel
Run “bitbake linux-adi -C compile” to compile the linux kernel to generate the zImage and dtb file.
A kernel image and dtb file can now be built and loaded onto the target board. See SC5xx ezkit Linux quick start guide for details.
Usage of MSI
The most typical use of an SD Card in embedded applications is as a removable storage device (disk) that can be easily taken from the embedded target board. In such contexts, the SD Card installed to the embedded target board is typically already formatted with an MS-DOS file system. The Linux kernel must be specially configured to allow mounting the MS-DOS file system. See part 2 in section 2.1 for details. The mount utility is also needed. Typically, mount will already be enabled in your busybox configuration.
Formatting the SD Card
In order to use an SD Card with Linux we need to prepare it by formatting it in the correct format.
This section of instructions requires you to correctly identify the SD Card and format the card. If you select the wrong drive you may cause irreversible damage to you Host PC.
To format the SD Card, follow the commands below. The example code in this section assumes that the SD Card device is reported to be /dev/sdb. Ensure that you change these commands to use your device.
$ sudo fdisk /dev/sdb
/* Create primary partition 1, 256M size*/
Command (m for help): n
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-3887103, default 2048): PRESS ENTER
Last sector, +sectors or +size{K,M,G} (2048-3887103, default 3887103): PRESS ENTER
/* Save partition */
Command (m for help): w
Format the SD card to MS-DOS (FAT) filesystem
# mkfs.vfat -F 32 /dev/mmcblk0p1
Format the SD card to EXT filesystem
# mkfs.ext3 /dev/mmcblk0p1
Insert a pre-formatted card with an MS-DOS (FAT) file system to the SD Card slot on the ADSP-SC5xx
When you boot the zImage on the ADSP-SC5xx, there should be messages similar to the ones shown below. In the below example, Linux has detected an SD Card with a single partition on it:
mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req 25000000Hz, actual 25000000HZ div = 1) mmc0: new SD card at address b368 mmcblk0: mmc0:b368 FFFFF 1.85 GiB
Mount the MS-DOS file system on the SD Card
This is done as follows:
# mount -t vfat -o sync /dev/mmcblk0p1 /mnt
Check that the file system has indeed been mounted
Refer to the last line in the below output:
# mount rootfs on / type rootfs (rw) devtmpfs on /dev type devtmpfs (rw,relatime,size=42740k,nr_inodes=10685,mode=755) proc on /proc type proc (rw,relatime) devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620) tmpfs on /dev/shm type tmpfs (rw,relatime,mode=777) tmpfs on /tmp type tmpfs (rw,relatime,mode=777) sysfs on /sys type sysfs (rw,relatime) debugfs on /sys/kernel/debug type debugfs (rw,relatime) /dev/mmcblk0p1 on /mnt type vfat (rw,sync,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
Write something to the SD Card
In the below example, we store the current date and time to a log file, although in real-life applications you will probably want to do something more meaningful:
# date > /mnt/log.file
Verify the written content by reading the log file back
# cat /mnt/log.file Fri Jul 17 05:31:49 UTC 2020
Unmount the file system and then extract the card from the SD card slot
Now you can remove the card the from the embedded target board.
# umount /mnt mmc0: card b368 removed
Test MSI Performance with Bonnie++
1) Test Case 1: Bonnie++ on Ext2
Input the following command on the target board console
root@adsp-sc589-ezkit:~# mkfs.ext2 /dev/mmcblk0p1 root@adsp-sc589-ezkit:~# mount /dev/mmcblk0p1 /mnt/ root@adsp-sc589-ezkit:~# bonnie++ -u root -d /mnt/
Result
Using uid:0, gid:0.
Writing with putc()...done
Writing intelligently...done
Rewriting...done
Reading with getc()...done
Reading intelligently...done
start 'em...done...done...done...
Create files in sequential order...done.
Stat files in sequential order...done.
Delete files in sequential order...done.
Create files in random order...done.
Stat files in random order...done.
Delete files in random order...done.
Version 1.04 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
adsp-sc589-ezk 424M 7985 77 8227 8 3920 6 8538 90 8660 6 1220 18
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 6513 92 16713 84 10240 97 149 98 +++++ +++ 12912 98
adsp-sc589-ezkit,424M,7985,77,8227,8,3920,6,8538,90,8660,6,1220.4,18,16,6513,92,16713,84,10240,97,149,98,+++++,+++,12912,98
2) Test Case 2: Bonnie++ on FAT32
Input the following command on the target board console
root@adsp-sc589-ezkit:~# mkfs.vfat -F 32 /dev/mmcblk0p1
root@adsp-sc589-ezkit:~# mount /dev/mmcblk0p1 /mnt/
root@adsp-sc589-ezkit:~# bonnie++ -u root -d /mnt/
Using uid:0, gid:0.
Writing with putc()...done
Writing intelligently...done
Rewriting...done
Reading with getc()...done
Reading intelligently...done
start 'em...done...done...done...
Create files in sequential order...done.
Stat files in sequential order...done.
Delete files in sequential order...done.
Create files in random order...done.
Stat files in random order...done.
Delete files in random order...done.
Version 1.04 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
adsp-sc589-ezk 424M 4405 44 6886 10 4026 7 8360 89 8658 6 803.4 12
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 9 99 +++++ +++ 147 99 17 99 +++++ +++ 39 98
adsp-sc589-ezkit,424M,4405,44,6886,10,4026,7,8360,89,8658,6,803.4,12,16,9,99,+++++,+++,147,99,17,99,+++++,+++,39,98
Back to Kernel Features and Device Drivers for ADSP-SC5xx Yocto Linux
resources/tools-software/linuxdsp/docs/linux-kernel-and-drivers/mmc/mmc.txt · Last modified: 17 Jul 2020 09:58 by Sunny Feng