Le 18/03/2014 13:34, Stefano Babic a écrit :
Hi Thierry,
On 18/03/2014 12:28, tbultel@free.fr wrote:
Hi,
I am working on a board (AMOS820 from Via) based on the mx6qsabrelite.
The BSP provided by the manufacturer is quite old. I managed to port it from Freescale uboot-imx rel_imx_3.0.35_4.1.0 to u-boot mainline, and basically the latest issue I have is the cpu frequency.
The kernel I use is the rel_imx_3.0.35_4.1.0 as well (same tag name)
With the old u-boot, it runs at 1Ghz because the BSP explicitly has a call to
clk_config(CONFIG_REF_CLK_FREQ, 1000, CPU_CLK);
With the new u-boot, it runs at default freq which is 800Mhz (at least, what I guess from the Bogomips because no other log says it)
It is can taken as reference, but checking the BogoMIPS is not the right way to proof it. You should take a look at the CCM registers when Linux is running ( CCM_ANALOG_PLL_ARM).
I have attempted to pass "arm_freq=1000" to the boot args but that does not change anything.
Well, this is a kernel issue, and related to an ancient version.
My concern is that clk_config does not seem to be available anymore, there is get_mcu_main_clk but no set routine.
It was never available in mainline.
I wonder if it is intentional, I could write a set routine but I wonder if it could be accepted as a patch.
Why not ? All patches are discussed here and if it makes sense to merge it, it will be merged.
Hi Stefano, many thanks for your advice,
It is now running at 1Ghz. I still have a couple of issues that prevent me to submit a patch as is:
1) The kernel (old, I know) I am using does not like that PCIe to have been formerly probed by u-boot. It hangs at probing if so. Thus I have to patch my kernel, or add an environment variable to not initialize PCIe when set, in order to keep compatible with old kernels. For now, in order to boot, I have temporary disabled PCIe support in U-boot.
2) The splashscreen (loaded at 10000000) disappears when loading the kernel Would you have any idea or hints about it ?
Best Regards Thierry
Best regards, Stefano Babic