Hi Fabio,
On Tue, Nov 25, 2014 at 8:56 PM, Fabio Estevam festevam@gmail.com wrote:
On Tue, Nov 25, 2014 at 5:48 PM, Benoît Thébaudeau benoit.thebaudeau.dev@gmail.com wrote:
That, or:
- Make imx_get_mac_from_fuse() call enable_ocotp_clk(1) before
reading the fuses, then call enable_ocotp_clk(0).
Yes, I started with this exact same approach as well. It works, but Nitin told me he also had similiar issues with hab.
Other issue I see with such approach is that if people would try to read the ocotp registers manually in the U-boot prompt (via md.l command), then they will also get a hang.
If users access the OCOTP registers manually, they can also enable the OCOTP clock in the corresponding register beforehand, even if this complicates things.
- Make enable_ocotp_clk() return the clock initial state and store it
in prepare_access(), then restore it in finish_access(). Same in imx_get_mac_from_fuse().
This would work as well, but with some more complexity. Still would cause the hang via manual readings.
Which of these 3 choices do you think would be the best?
I think the simplest one and the one that would be more general would be the one proposed by this patch.
The only possible issue that I see with leaving the OCOTP clock enabled is the risk of inadvertently writing the fuses, either in U-Boot or in the booted OS. That being said, Freescale advise against leaving the fuses powered for production boards, in which cases there is no such risk.
Reviewed-by: Benoît Thébaudeau benoit.thebaudeau.dev@gmail.com
Regards, Benoît