BeagleBoard sdrc init writes reserved values
In sdrc_init in board-beagle.c both
writel(0x1A, SDRC_REG(SYSCONFIG));
and
writel(0x18, SDRC_REG(SYSCONFIG));
sets bits 4:3 in the IDLEMODE field. The OMAP3 TRM (spruf98k) defines 0x2 as the only valid value for this field, all others being marked as "reserved - do not use". board-omap3evm.c does the same thing, board-sdp343x.c does not.
Anyone knows where these settings come from? Derived from an older version of the TRM? (I'm thinking there may have been a feature that was discovered to be unreliable or not working as intended so it was removed from the docs.)
Thanks,
Orjan
Signature · 7 lines
Orjan Friberg FlatFrog Laboratories AB _______________________________________________ barebox mailing list [email protected] http://lists.infradead.org/mailman/listinfo/barebox
Hi Orjan,
Quoted 13 lines · Orjan Friberg
In
sdrc_initinboard-beagle.cbothwritel(0x1A, SDRC_REG(SYSCONFIG));and
writel(0x18, SDRC_REG(SYSCONFIG));sets bits 4:3 in the IDLEMODE field. The OMAP3 TRM (spruf98k) defines
0x2as the only valid value for this field, all others being marked as "reserved - do not use".board-omap3evm.cdoes the same thing,board-sdp343x.cdoes not.
Quoted 4 lines
Anyone knows where these settings come from? Derived from an older version of the TRM? (I'm thinking there may have been a feature that was discovered to be unreliable or not working as intended so it was removed from the docs.)
I have no idea. I'm pretty sure though that the value has been copied from some version of U-Boot or Xloader.
Sascha
Signature · 9 lines
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Quoted 16 lines · Sascha Hauer
Hi Orjan,
Quoted 13 lines · Orjan Friberg
In
sdrc_initinboard-beagle.cboth
writel(0x1A, SDRC_REG(SYSCONFIG));and
writel(0x18, SDRC_REG(SYSCONFIG));sets bits 4:3 in the IDLEMODE field. The OMAP3 TRM (spruf98k) defines
0x2as the only valid value for this field, all others being marked as "reserved - do not use". board-omap3evm.c does the same thing,board-sdp343x.cdoes not.
Quoted 8 lines
Quoted 4 lines
Anyone knows where these settings come from? Derived from an older version of the TRM? (I'm thinking there may have been a feature that was discovered to be unreliable or not working as intended so it was removed from the docs.)
I have no idea. I'm pretty sure though that the value has been copied from some version of U-Boot or Xloader.
I agree - I think this is an accident - probably copied from older loader versions and introduced in the first version that went here.
- Anand
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Quoted 11 lines · Anand Gadiyar
Quoted 8 lines
Quoted 4 lines
Anyone knows where these settings come from? Derived from an older version of the TRM? (I'm thinking there may have been a feature that was discovered to be unreliable or not working as intended so it was removed from the docs.)
I have no idea. I'm pretty sure though that the value has been copied from some version of U-Boot or Xloader.
I agree - I think this is an accident - probably copied from older loader versions and introduced in the first version that went here.
Ok, thanks. (We haven't seen any problems related to those settings, we just checked them out of curiosity since we noticed there was a difference between barebox/x-load/u-boot. )
Signature · 7 lines
Orjan Friberg FlatFrog Laboratories AB _______________________________________________ barebox mailing list [email protected] http://lists.infradead.org/mailman/listinfo/barebox