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{{AppliesToSBCLynx}}
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This article details how physical devices are mapped to handled by the Linux device files kernel in the context of the [[AXEL_ULite_and_SBC_Lynx_Embedded_Linux_Kit_(XUELK)|XUELK kit]]. == History == {| class="wikitable" border="1"!Version!Date![[AXEL_ULite_and_SBC_Lynx_Embedded_Linux_Kit_(XUELK)|XUELK version]]!Notes|-|{{oldid|6648|1.0.0}}|December 2016|1.0.0|First public release|-|1.2.0|May 2017|1.2.0|Update for new XUELK release|-|2.0.0|September 2017|2.0.0|Validated on latest XUELK release|-|}
==Console UART==
{| class="wikitable"
|}
==Multi-protocol UARTs==
{{ImportantMessage|text=From [[AXEL_ULite_and_SBC_Lynx_Embedded_Linux_Kit_(XUELK)|XUELK]] version 1.2.0 UART are automatically initialized at boot time, depending on [[ConfigID (XUELK)|ConfigID]]. For XUELK release 1.1.3 and below, in order to use UART8 as RS232 interface, some GPIOs need to be configured as follows explained {{oldid|6648|into release 1.0.0 of this page}} }}
===Ordering code: XUBxx0xxx0x===
{| class="wikitable"
| MPUART0 || UART7 || J34 || 2-wire RS232 || <code>/dev/ttymxc6</code> ||
|-
| MPUART1 || UART3 || J21 || RS485 [1]|| <code>/dev/ttymxc2</code> ||
|-
|}
===Ordering code: XUBxx0xxx1xXUBxx0xxxxx===
{| class="wikitable"
|-
| MPUART0 || UART8 || J34 || 2-wire RS232 || <code>/dev/ttymxc7</code> ||
|-
| MPUART1 || UART3 || J21 || RS485 [1] || <code>/dev/ttymxc2</code> |||-|} [1] Supported baud rate range: 9600 Bps - 115200 Bps. ===Ordering code: XUBxx3xxxxx==={| class="wikitable"|-! Physical device !! Processor's resource !! Connector !! Type !! Linux device file !! Notes|-| MPUART0 || UART8 || J38 || RS485 [1] || <code>/dev/ttymxc7</code> |||-| MPUART1 || UART3 || J39 || RS485 [1] || <code>/dev/ttymxc2</code> ||
|-
|}
[1] Supported baud rate range: 9600 Bps - 115200 Bps.
==UART2 on mezzanine connector J53==
Please note that '''this UART is not available if WiFi/Bluetooth module is populated'''.
|-
|}
==Ethernet==
Ethernet port is associated to <code>eth0</code> interface. It can be managed with standard Linux commands. See for example http://www.tecmint.com/ifconfig-command-examples/.
==GPIOs on mezzanine connector J53==
{| class="wikitable"
|-
! Processor's resource !! Connector .pin# !! Type !! Linux virtual resource !! Notes
|-
| MX6UL_PAD_UART5_RX_DATA__GPIO1_IO31 || J53 .6 || LVTTL GPIO || GPIO #31 || see following examples
|-
| MX6UL_PAD_UART5_TX_DATA__GPIO1_IO30 || J53 .5 || LVTTL GPIO || GPIO #30 || see following examples
|-
| MX6UL_PAD_LCD_DATA19__GPIO3_IO24 || J53 .7 || LVTTL GPIO || GPIO #24 || see following examples
|-
| MX6UL_PAD_LCD_DATA22__GPIO3_IO27 || J53 .8 || LVTTL GPIO || GPIO #27 || see following examples
|-
| MX6UL_PAD_LCD_DATA23__GPIO3_IO28 || J53 .9 || LVTTL GPIO || GPIO #28 || see following examples
|-
|}
==WiFi/Bluetooth==
Please refer to [[XUELK-AN-001:_Using_WiFi-Bluetooth_combo_plugin_with_SBC_Lynx|this page]].
==NOR and NAND flash==
NOR and NAND flashes are managed as [[Memory_Tecnology_Device_(MTD)|MTD devices]].
Generally speaking, their partitioning is defined via Linux kernel command line. For instance this command line
<pre>
mtdparts=gpmi-nand:8M(nand-uboot),1M(nand-env1),1M(nand-env2),1M(nand-fdt),1M(nand-spare),8M(nand-kernel),4M(nand-splash),-(nand-ubi);spi0.0:1M(spi-uboot),256k(spi-env1),256k(spi-env2),512k(spi-dtb),6M(spi-kernel),4M(spi-splash),-(spi-free)
</pre>
defines these partitions:
<pre>
root@sbc-lynx:~# cat /proc/mtd
dev: size erasesize name
mtd0: 00800000 00020000 "nand-uboot"
mtd1: 00100000 00020000 "nand-env1"
mtd2: 00100000 00020000 "nand-env2"
mtd3: 00100000 00020000 "nand-fdt"
mtd4: 00100000 00020000 "nand-spare"
mtd5: 00800000 00020000 "nand-kernel"
mtd6: 00400000 00020000 "nand-splash"
mtd7: 3e800000 00020000 "nand-ubi"
mtd8: 00100000 00010000 "spi-uboot"
mtd9: 00040000 00010000 "spi-env1"
mtd10: 00040000 00010000 "spi-env2"
mtd11: 00080000 00010000 "spi-dtb"
mtd12: 00600000 00010000 "spi-kernel"
mtd13: 00400000 00010000 "spi-splash"
mtd14: 01400000 00010000 "spi-free"
</pre>
==ADCs==
The following processor's signals are available on J54 mezzanine connector and can be configured as 12-bit ADC inputs:
*<code>GPIO1_IO01</code>
*<code>GPIO1_IO02</code>
*<code>GPIO1_IO03</code>
*<code>GPIO1_IO04</code>
*<code>GPIO1_IO05</code>
To read the digital value of the converted analog voltage, issue the following command (the example refers to the <code>GPIO1_IO05</code> pin):
<pre>
cat /sys/bus/iio/devices/iio\:device0/in_voltage5_raw
</pre>
==USB OTG==
===Host mode===
This example shows how a memory stick is detected by the Linux kernel.
<pre>
root@sbc-lynx:~# ci_hdrc ci_hdrc.0: EHCI Host Controller
ci_hdrc ci_hdrc.0: new USB bus registered, assigned bus number 2
ci_hdrc ci_hdrc.0: USB 2.0 started, EHCI 1.00
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 1 port detected
usb 2-1: new high-speed USB device number 2 using ci_hdrc
usb-storage 2-1:1.0: USB Mass Storage device detected
scsi0 : usb-storage 2-1:1.0
scsi 0:0:0:0: Direct-Access General USB Flash Disk 1.00 PQ: 0 ANSI: 2
sd 0:0:0:0: [sda] 7831552 512-byte logical blocks: (4.00 GB/3.73 GiB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] No Caching mode page found
sd 0:0:0:0: [sda] Assuming drive cache: write through
sd 0:0:0:0: [sda] No Caching mode page found
sd 0:0:0:0: [sda] Assuming drive cache: write through
sda: sda1
sd 0:0:0:0: [sda] No Caching mode page found
sd 0:0:0:0: [sda] Assuming drive cache: write through
sd 0:0:0:0: [sda] Attached SCSI removable disk
FAT-fs (sda1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
</pre>
To connect it to micro B connector (J55), a cable like the one shown in the following picture has been used [1].
[[File:Usb-cable-micro-host.jpg|thumb|center|USB cable used to connect memory stick]]
Once mounted (at <code>/run/media/sda1</code> in the example), the memory stick can be accessed by regular commands:
<pre>
root@sbc-lynx:~# mount
rootfs on / type rootfs (rw)
192.168.0.13:/opt/nfsroot/lynx/xuelk on / type nfs (rw,relatime,vers=3,rsize=4096,wsize=4096,namlen=255,hard,nolock,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=192.168.0.13,mountvers=3,mountproto=tcp,local_lock=all,addr=192.168.0.13)
devtmpfs on /dev type devtmpfs (rw,relatime,size=89856k,nr_inodes=22464,mode=755)
proc on /proc type proc (rw,relatime)
tmpfs on /mnt/.psplash type tmpfs (rw,relatime,size=40k)
sysfs on /sys type sysfs (rw,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
tmpfs on /run type tmpfs (rw,nosuid,nodev,mode=755)
tmpfs on /var/volatile type tmpfs (rw,relatime)
devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620)
/dev/sda1 on /run/media/sda1 type vfat (rw,relatime,gid=6,fmask=0007,dmask=0007,allow_utime=0020,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
root@sbc-lynx:~# cp test.bin /run/media/sda1/
root@sbc-lynx:~# umount /run/media/sda1
root@sbc-lynx:~# mount /dev/sda1 /run/media/sda1/
FAT-fs (sda1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
root@sbc-lynx:~# md5sum test.bin
1a2cd22d44aa0520f0f9621e41e0ecb9 test.bin
root@sbc-lynx:~# md5sum /run/media/sda1/test.bin
1a2cd22d44aa0520f0f9621e41e0ecb9 /run/media/sda1/test.bin
</pre>
[1] This type of cables forces the ID signal of the USB port to be connected to ground, selecting the host mode on SBC Lynx side.
===Device mode===
The following examples shows how to configure SBC Lynx to act as a mass storage device.
First, a local file named <code>mass</code> is created to emulate a mass storage disk that is populated with a file named <code>file.txt</code>:
<pre>
root@sbc-lynx:~# dd if=/dev/zero of=mass count=16 bs=1M
16+0 records in
16+0 records out
root@sbc-lynx:~# mkfs.msdos mass
mkfs.msdos 2.11 (12 Mar 2005)
root@sbc-lynx:~# mkdir loop
root@sbc-lynx:~# mount -o loop mass loop
root@sbc-lynx:~# echo dummy > loop/file.txt
root@sbc-lynx:~# umount loop
</pre>
Then the proper drivers are loaded on target side:
<pre>
root@sbc-lynx:~# insmod modules/libcomposite.ko
root@sbc-lynx:~# insmod modules/usb_f_mass_storage.ko
root@sbc-lynx:~# insmod modules/g_mass_storage.ko file=mass
Number of LUNs=8
Mass Storage Function, version: 2009/09/11
LUN: removable file: (no medium)
Number of LUNs=1
LUN: file: /home/root/mass
Number of LUNs=1
g_mass_storage gadget: Mass Storage Gadget, version: 2009/09/11
g_mass_storage gadget: userspace failed to provide iSerialNumber
g_mass_storage gadget: g_mass_storage ready
</pre>
Last, SBC Lynx is connected to a PC with a USB cable like this one:
[[File:USB-cable-micro-host-a.png|thumb|center|400px|USB cable used to connect SBC Lynx to PC]]
On PC side, SBC Lynx is detected as a common USB mass storage device.
==USB host==
The following example shows how an USB memory stick is detected by the Linux kernel when plugged into the J48 connector:
<pre>
root@imx6ulevk:~# [ 75.584841] usb 1-1: new high-speed USB device number 2 using ci_hdrc
[ 75.742301] usb 1-1: New USB device found, idVendor=13fe, idProduct=3e00
[ 75.749941] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 75.757910] usb 1-1: Product: DISK
[ 75.761448] usb 1-1: Manufacturer: USB
[ 75.766141] usb 1-1: SerialNumber: 9BC3170089A71A0A
[ 75.777163] usb-storage 1-1:1.0: USB Mass Storage device detected
[ 75.786170] scsi0 : usb-storage 1-1:1.0
[ 76.817769] scsi 0:0:0:0: Direct-Access USB DISK PMAP PQ: 0 ANSI: 4
[ 79.046564] sd 0:0:0:0: [sda] 15646720 512-byte logical blocks: (8.01 GB/7.46 GiB)
[ 79.056659] sd 0:0:0:0: [sda] Write Protect is off
[ 79.062243] sd 0:0:0:0: [sda] No Caching mode page found
[ 79.068416] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 79.083946] sd 0:0:0:0: [sda] No Caching mode page found
[ 79.089858] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 79.122209] sda: sda1
[ 79.139095] sd 0:0:0:0: [sda] No Caching mode page found
[ 79.146243] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 79.152561] sd 0:0:0:0: [sda] Attached SCSI removable disk
[ 80.060663] FAT-fs (sda1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
</pre>
Once mounted (at <code>/mnt/usb/</code> in the example), the memory stick can be accessed with regular commands:
<pre>
root@imx6ulevk:~# mkdir /mnt/usb
root@imx6ulevk:~# mount /dev/sda1 /mnt/usb/
root@imx6ulevk:~# time cp LibreOffice_4.1.1_Win_x86.msi /mnt/usb/; sync
real 0m47.236s
user 0m0.020s
sys 0m8.590s
root@imx6ulevk:~# ls -la /mnt/usb/
total 215152
drwxrwx--- 3 root disk 4096 Mar 4 20:48 .
drwxr-xr-x 5 500 502 4096 Mar 9 2016 ..
-rwxrwx--- 1 root disk 112328 Jan 14 18:47 CoreIBEXarm
-rwxrwx--- 1 root disk 215056384 Mar 4 20:49 LibreOffice_4.1.1_Win_x86.msi
-rwxrwx--- 1 root disk 173 Jan 1 1980 UpdateIBEX.log
drwxrwx--- 2 root disk 4096 Jan 1 1980 UpdateIBEX19700101010500
-rwxrwx--- 1 root disk 1303 Feb 19 12:36 Xilinx_OSD_19-02-2016.lic
-rwxrwx--- 1 root disk 5105327 Jan 18 16:31 ibex.war
-rwxrwx--- 1 root disk 105 Jun 10 2015 update-script.sh
-rwxrwx--- 1 root disk 6494 Jan 18 16:52 update-script_.sh
root@imx6ulevk:~# umount /mnt/usb/
root@imx6ulevk:~#
root@imx6ulevk:~#
root@imx6ulevk:~# [ 456.298630] usb 1-1: USB disconnect, device number 2
</pre>
