Hi Benoît, hi Fabio, On 17/12/2013 22:18, Benoît Thébaudeau wrote: > Hi Fabio, > > On Tuesday, December 17, 2013 9:03:40 PM, Fabio Estevam wrote: >> From: Fabio Estevam <[email protected]> >> >> When using the fuse API in U-boot user must calculate the 'bank' and 'word' >> values. >> >> Provide a real example on how to calculate such values for the mx6q. >> >> Signed-off-by: Fabio Estevam <[email protected]> >> --- >> doc/README.fuse | 57 >> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 57 insertions(+) >> >> diff --git a/doc/README.fuse b/doc/README.fuse >> index 1bc91c4..aca1e5e 100644 >> --- a/doc/README.fuse >> +++ b/doc/README.fuse >> @@ -65,3 +65,60 @@ Configuration: >> >> CONFIG_CMD_FUSE >> Define this to enable the fuse commands. >> + >> +Example: >> + >> +For reading the MAC address fuses on a MX6Q: >> + >> +- The MAC address are stored in two fuse addresses (the fuse addresses are >> +described in the Fusemap Descriptions table from the mx6q Reference Manual): >> + >> +0x620[31:0] - MAC_ADDR[31:0] >> +0x630[15:0] - MAC_ADDR[47:32] >> + >> +In order to use the fuse API, we need to pass the bank and word values, >> which >> +are calculated as below: >> + >> +Fuse address for the lower MAC address: 0x620 >> +Base address for the fuses: 0x400 >> + >> +(0x620 - 0x400)/0x10 = 0x22 = 34 decimal >> + >> +As the fuses are arranged in banks of 8 words: >> + >> +34 / 8 = 4 and the remainder is 2, so in this case: >> + >> +bank = 4 >> +word = 2 >> + >> +And the U-boot command would be: >> + >> +=> fuse read 4 2 >> +Reading bank 4: >> + >> +Word 0x00000002: 9f027772 >> + >> +Doing the same for the upper MAC address: >> + >> +Fuse address for the upper MAC address: 0x630 >> +Base address for the fuses: 0x400 >> + >> +(0x630 - 0x400)/0x10 = 0x23 = 35 decimal >> + >> +As the fuses are arranged in banks of 8 words: >> + >> +35 / 8 = 4 and the remainder is 3, so in this case: >> + >> +bank = 4 >> +word = 3 >> + >> +And the U-boot command would be: >> + >> +=> fuse read 4 3 >> +Reading bank 4: >> + >> +Word 0x00000003: 00000004 >> + >> +,which matches the ethaddr value: >> +=> echo ${ethaddr} >> +00:04:9f:02:77:72 >> -- >> 1.8.1.2 > > Note that the documentation in this file is also completed for i.MX6 by > doc/README.mxc_ocotp and doc/README.imx6, as explained in each README. The > information that you add here regarding the location of the MAC fuses for > i.MX6Q > is already present in doc/README.imx6.
This is true, but the current documentation is poor. I like that Fabio adds a real example, providing a better understanding. IMHO we should avoid to add a new file, if (as it is), this patch is only for i.MX6. Putting it in README.imx6 seems the best solution. > > Regarding the 'calculation' part, it is actually not needed since the values > obtained with these calculations are already given by the reference manual in > '46.5 OCOTP Memory Map/Register Definition'. A reference is not bad, but of course documentation is changing. I was working with manual 04/2013, and there is not an example - only "empty example". Anyway, most people is searching exactly how to store in SOC the MAC address - not how to write another fuse. I think it is a good idea to add the MAC's example, because it is what most people are looking for. > > Examples could still be interesting though. What do you think? > - Should the calculation part be removed and replaced with a reference to the > RM §46.5 be added? I will add only a refererence, but I will let the example. > - Should this example be moved to doc/README.imx6, +1, as the example is only for i.MX6. Best regards, Stefano Babic -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: [email protected] ===================================================================== _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
