topic Re: Enable CSU in imx6 in i.MX Processors

Enable CSU in imx6

kajalsabhani — Thu, 21 Apr 2016 08:41:02 GMT

Hi all,

As per CSU_CSL registers default value ,it has secure read /write permission by default .(CSU_CSL=0x00330033)

I am not getting that even though it has secure read/write access permission then how that peripheral can be accessed from linux kernel.

is it that linux kernel is operating in secure mode?

i want to add CSU for secure and non secure access of peripherals .

so help me on how to enable CSU in imx6.

Thanks

Re: Enable CSU in imx6

art — Fri, 22 Apr 2016 06:23:53 GMT

Q. is it that linux kernel is operating in secure mode?

A. The Linux kernel code is executed in the ARM hardware Supervisor mode, so, it has the Secure level of access.

Q. i want to add CSU for secure and non secure access of peripherals . so help me on how to enable CSU in imx6.

A. Please refer to the Chapter 3 of the i.MX6 Series Security Reference Manual document, available for download on the NXP web site (check the "Reference Manuals" section):

http://www.nxp.com/products/microcontrollers-and-processors/arm-processors/i.mx-applications-processors/i.mx-6-processors/i.mx6qp/i.mx-6quad-processors-high-performance-3d-graphics-hd-video-arm-cortex-a9-core:i.MX6Q?fpsp=1&tab=Documentation_Tab

Have a great day,
Artur

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Re: Enable CSU in imx6

kajalsabhani — Fri, 22 Apr 2016 06:43:46 GMT

As linux is in supervisor mode and has secured level of access then how i configure linux for user mode and non secure access

Re: Enable CSU in imx6

art — Fri, 22 Apr 2016 07:02:34 GMT

It is not possible to make the Linux kernel run in User mode.

Re: Enable CSU in imx6

kajalsabhani — Fri, 22 Apr 2016 07:49:23 GMT

Ok .

so using CSU we can provide non secure accesss .

for that SMC (secure monitor calling) is required . right?