On 26.11.2012 17:03, Benoît Thébaudeau wrote:
Hi Eric, all,
On Thursday, August 23, 2012 3:23:20 PM, Eric Nelson wrote:
On 08/23/2012 03:31 AM, Stefano Babic wrote:
On 22/08/2012 12:43, Dirk Behme wrote:
On 14.08.2012 14:52, Benoît Thébaudeau wrote:
This can be useful for fuse-like hardware, OTP SoC options, etc.
For i.MX6, I have a port of the OTP support from Freescale's U-Boot to our mainline U-Boot in the queue [1].
As I don't have the overview over the various i.MXxx SoCs and don't understand much of this patch below: Should this implement the same functionality like my patch [1] for i.MX6?
I have not checked the details. but seeing the code it looks that the procedure to read / write are different. In this case, a further driver is ok.
Anyway, you should take a look if your patches can be used on a mxs (MX28) device, because they should be closer. And then I will not like to have a driver for each SOC.
Generally, I think we should use the approach of the common command and a specific fuse implementation. Then this API should be used by your patches as well.
I agree.
The use of the fuse API will likely result in more code than the imxotp implementation, and more importantly, it will make the usage more confusing by introducing terms bank and row.
Reading and writing fuses is probably not an area that we want confusion.
I am looking again into this question now that I have the i.MX6 reference manual.
I don't see any difference between IIM and OCOTP features:
- There are still banks: They exist as seen from the controller, even if they don't exist physically in the efusebox. See 46.2.1 and OCOTP memory map ("Value of OTP Bankx Wordy" shadow registers).
- Rows are named words.
- The read operations are read accesses to the shadow registers.
- The sense operations are direct fuse reads (shadow reload + read), as explained by the steps in 46.2.1.2.
- The prog operations are the programming of the fuses, as explained by the steps in 46.2.1.3.
- The override operations are simple write accesses to the shadow registers, as explained in 46.2.1.3.
As to the vocabulary used, the differences are:
- "row" -> "word".
- "sense" -> "direct read".
Hence, the fuse API applies very well in this case too.
Do you like to update/rebase your patches to the latest U-Boot and re-send? Maybe it makes sense to discuss your patches again, then?
Eric: What do you think?
Thanks
Dirk