This patch adds support for the following computer on modules (CoM) from
Toradex[A]:
Apalis iMX6 Quad 2GB IT - i.MX 6Quad 800MHz, 2GB DDR3, 4GB eMMC
-40° to +85° C Temp
Apalis iMX6 Quad 1GB - i.MX 6Quad 1GHz, 1GB DDR3, 4GB eMMC
0° to +70° C Temp
Apalis iMX6 Dual 1GB IT - i.MX 6Dual 800MHz, 1GB DDR3, 4GB eMMC
-40° to +85° C Temp
Apalis iMX6 Dual 512MB - i.MX 6Dual 1GHz, 512MB DDR3, 4GB eMMC
0° to +70° C Temp
I've developed and tested it on Quad 2GB IT v1.1A and Dual 512MB v1.1A
CoMs, using Ixora[B] carrier board v1.0A, but it should hopefuly work on
Eval[C] board as well.
A. https://www.toradex.com/computer-on-modules/apalis-arm-family/nxp-freescale-imx-6
B. https://www.toradex.com/products/carrier-board/ixora-carrier-board
C. https://www.toradex.com/products/carrier-board/apalis-evaluation-board
Flashing/recovery instructions:
1. Download and compile imx_loader for OpenWrt from
https://github.com/ynezz/imx_loader
2. Enter recovery mode as desribed in
https://developer.toradex.com/knowledge-base/imx-recovery-mode
3. Connect board via USB to the host computer, check that it's connected
by lsusb:
15a2:0054 Freescale Semiconductor, Inc. i.MX 6Dual/6Quad SystemOnChip
in RecoveryMode
4. Copy following OpenWrt images to imx_loader directory:
SPL
u-boot.img
u-boot-with-spl.imx
openwrt-imx6-apalis-recovery.scr
openwrt-imx6-apalis-squashfs.combined.bin
5. Run imx_usb in imx_loader directory
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Following errors were seen in the past on imx6 when using serial:
[ 22.617622] imx-uart 2020000.serial: DMA transaction error.
[ 22.623228] imx-uart 2020000.serial: DMA transaction error.
[ 22.628826] imx-uart 2020000.serial: DMA transaction error.
[ 22.648951] imx-uart 2020000.serial: DMA transaction error.
[ 22.654558] imx-uart 2020000.serial: DMA transaction error.
[ 22.660156] imx-uart 2020000.serial: DMA transaction error.
Which is the reason why DMA for the serial ports
got disabled in commits:
efb362cd93 ("imx6: disable dma on uart")
3b4241071d ("imx6: disable UART dma")
As indicated on mailinglist discussion, the cause seems to be
the usage of very old SDMA firmware which is present in the soc:
[ 0.624302] imx-sdma 20ec000.sdma: Direct firmware load for imx/sdma/sdma-imx6q.bin failed with error -2
[ 0.624318] imx-sdma 20ec000.sdma: Falling back to user helper
[ 64.531607] imx-sdma 20ec000.sdma: external firmware not found, using ROM firmware
This patch adds the new firmware binary. (2196 bytes)
It is required to embed the binary into the kernel image, as it
gets loaded very early in the boot process where the rootfs is not
available yet:
[ 0.622966] imx-sdma 20ec000.sdma: loaded firmware 3.3
Extended testing shows that the DMA errors are not seen anymore
when using this newer firmware version.
Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
When this target got updated to 4.14, this patch got removed to
re-evaluate if it was still needed.
Extensive testing now shows this issue is still present.
Let's re-add the patch to fix it for now.
As the uart bus is very low bandwidth .. performance impact is negligible.
Boot log:
[ 22.513051] imx-uart 2020000.serial: DMA transaction error.
[ 22.522721] imx-uart 2020000.serial: DMA transaction error.
As a sidenote:
The patch mentiones an issue with RS485, but the bootlog
errors above were recorded with the uart ports in standard RS232 mode.
Compile/Run-tested on imx6/GW5200
Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Petr Štetiar
Koen Vandeputte
Tim Harvey