Dose imx257 supports RTLinux?

harihkumar — Thu, 07 Nov 2013 11:36:57 GMT

I am using imx257 for linux-2.6.31. I want to use RTLinux In imx257.

Can you please let me know how to integrate RTLinux to imx257?

Re: Dose imx257 supports RTLinux?

fabio_estevam — Thu, 07 Nov 2013 14:32:26 GMT

You could use a more recent kernel, such as 3.10 and aply the RT patches on top of it:

https://www.kernel.org/pub/linux/kernel/projects/rt/

Regards,

Fabio Estevam

Re: Dose imx257 supports RTLinux?

jppoulin — Mon, 26 Jan 2015 15:15:51 GMT

Hi! Has there been any development on RTLinux on the MX25 / MX28?

Has anyone been able to construct a robust RTLinux system on these Freescale chips? (I do not see any Freescale chips listed in the 'tested RTLinux' platforms at https://rt.wiki.kernel.org/index.php/CONFIG_PREEMPT_RT_Patch#Platforms_Tested_and_in_Use_with_CONFIG_PREEMPT_RT)

Jean-Pierre

Re: Dose imx257 supports RTLinux?

fmvalero — Mon, 06 Apr 2015 08:20:14 GMT

Currently, I have Linux 3.2.60 with RT patch applied running in my i.MX25 custom board. This is what I did (I assume LTIB and compiler gcc-4.4.4 are installed):

1. Download kernel from https://www.kernel.org/pub/linux/kernel/

2. Download RT patch for linux-3.2.60 from https://www.kernel.org/pub/linux/kernel/projects/rt/

3. Change compiler in PATH:

Replace: /opt/freescale/usr/local/gcc-4.1.2-glibc-2.5-nptl-3/arm-none-linux-gnueabi/bin/

By: /opt/freescale/usr/local/gcc-4.4.4-glibc-2.11.1-multilib-1.0/arm-fsl-linux-gnueabi/bin/

4. Set initial configuration:

# make imx_v4_v5_defconfig

5. Go to kernel configuration:

# make menuconfig

6. In Freescale MXC Implentations, select i.MX25 (all the other implementations must be unselected):

System Type --->

Freescale MXC Implementations --->

Freescale CPU family --->

(X) i.MX1, i.MX21, i.MX25, i.MX27

( ) i.MX3, i.MX6

( ) i.MX50, i.MX51, i.MX53

[*] Support MX25PDK (3DS) Platform

<*> Enable PWM driver

[ ] Enable MXC debug board(for 3-stack)

7. If you boot from Flash NAND, you have to edit the configuration file (.../linux-3.2.60/arch/arm/mach-imx/mach-mx25_3ds.c)

Add:

static struct mtd_partition mxc_nand_partitions[] = {

{

.name = "nand.bootloader",

.offset = 0,

.size = 3 * 1024 * 1024},

{

.name = "nand.kernel",

.offset = MTDPART_OFS_APPEND,

.size = 5 * 1024 * 1024},

{

.name = "nand.rootfs",

.offset = MTDPART_OFS_APPEND,

.size = 496 * 1024 * 1024},

{

.name = "nand.configure",

.offset = MTDPART_OFS_APPEND,

.size = 8 * 1024 * 1024},

{

.name = "nand.userfs",

.offset = MTDPART_OFS_APPEND,

.size = MTDPART_SIZ_FULL},

};

This partition table have to be set according your NAND size (mine is 512MB). I my case, rootfs is flashed at offset 0x800000 (i have 3MB for bootloader space and 5MB for kernel). You need to adjust this to your case.

Modify the struct mxc_nand_platform_data to add the partition table:

static const struct mxc_nand_platform_data mx25pdk_nand_board_info __initconst = {

.width = 1,

.hw_ecc = 1,

.flash_bbt = 1,

.parts = mxc_nand_partitions,

.nr_parts = ARRAY_SIZE(mxc_nand_partitions),

};

8. Compile kernel:

# make uImage

9. Apply RT patch. From the folder where linux-3.2.60 is:

# patch -p1 <../patch-3.2.60-rt87.patch

10. Go to kernel configuration again. Now, this can be selected:

Kernel Features --->

Preemption Model (Fully Preemptible Kernel (RT))--->

( ) No Forced Preemption (Server)

( ) Voluntary Kernel Preemption (Desktop)

( ) Preemptible Kernel (Low-Latency Desktop)

( ) Preemptible Kernel (Basic RT)

(X) Fully Preemptible Kernel (RT)

11. Finally, compile again the kernel.

# make uImage

This is the minimum you need to do to boot kernel. Later, you will need to modify configuration file to support all devices in your board.

Regards,

Fernando.

Re: Dose imx257 supports RTLinux?

jppoulin — Mon, 06 Apr 2015 12:41:15 GMT

Thank you very much Fernando for the usable response. Good news indeed! :smileyhappy:

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