[U-Boot] [PATCH 2/2] ARM: OMAP5: Enable support for AVS0 for OMAP5 production devices

[Lokesh Vutla]

On 8/5/2017 8:12 AM, Nishanth Menon wrote:
> OMAP5432 did go into production with AVS class0 registers which were
> mutually exclusive from AVS Class 1.5 registers.
> 
> Most OMAP5-uEVM boards use the pre-production Class1.5 which has
> production efuse registers set to 0. However on production devices,
> these are set to valid data.
> 
> scale_vcore logic is already smart enough to detect this and use the
> "Nominal voltage" on devices that do not have efuse registers populated.
> 
> On a test production device populated as follows:
> MPU OPP_NOM:
> => md.l 0x04A0021C4 1
> 4a0021c4: 03a003e9                               ....
> (0x3e9 = 1.01v) vs nom voltage of 1.06v
> MPU OPP_HIGH:
> => md.l 0x04A0021C8 1
> 4a0021c8: 03400485                               .. at .
> 
> MM OPP_NOM:
> => md.l 0x04A0021A4 1
> 4a0021a4: 038003d4                               ....
> (0x3d4 = 980mV) vs nom voltage of 1.025v
> MM OPP_OD:
> => md.l 0x04A0021A8 1
> 4a0021a8: 03600403                               ..`.
> 
> CORE OPP_NOM:
> => md.l 0x04A0021D8 1
> 4a0021d8: 000003cf                               ....
> (0x3cf = 975mV) vs nom voltage of 1.040v
> 
> Since the efuse values are'nt currently used, we do not regress on
> existing pre-production samples (they continue to use nominal voltage).
> 
> But on boards that do have production samples populated, we can leverage
> the optimal voltages necessary for proper operation.
> 
> Tested on:
> a) 720-2644-001 OMAP5UEVM with production sample.
> b) 750-2628-222(A) UEVM5432G-02 with pre-production sample.
> 
> Data based on OMAP5432 Technical reference Manual SWPU282AF (May
> 2012-Revised Aug 2016)
> 
> NOTE: All collaterals on OMAP5432 silicon itself seems to have been
> removed from ti.com, though EVM details are still available:
> http://www.ti.com/tool/OMAP5432-EVM
> 


Reviewed-by: Lokesh Vutla <lokeshvutla at ti.com>

Thanks and regards,
Lokesh


> Signed-off-by: Nishanth Menon <nm at ti.com>