[U-Boot] [PATCH v2 09/16] mtd/nand/tegra: alignment workaround

[Marcel Ziswiler]

On 28 July 2015 01:32:10 CEST, Scott Wood <scottwood at freescale.com> wrote:
>On Mon, 2015-07-27 at 17:28 -0600, Simon Glass wrote:
>> Hi Scott,
>> 
>> On 27 July 2015 at 13:57, Scott Wood <scottwood at freescale.com> wrote:
>> > On Tue, 2015-07-21 at 00:35 +0200, Marcel Ziswiler wrote:
>> > > From: Marcel Ziswiler <marcel.ziswiler at toradex.com>
>> > > 
>> > > Integrate cache alignment bounce buffer to workaround issues as
>follows:
>> > > 
>> > > Loading file '/boot/zImage' to addr 0x01000000 with size 4499152
>> > > (0x0044a6d0)...
>> > > ERROR: v7_dcache_inval_range - start address is not aligned -
>0x1f7f0108
>> > > ERROR: v7_dcache_inval_range - stop address is not aligned -
>0x1f7f1108
>> > > Done
>> > > Kernel image @ 0x1000000 [ 0x000000 - 0x44a6d0 ]
>> > > 
>> > > Starting kernel ...
>> > > 
>> > > undefined instruction
>> > > pc : [<005ff03c>]          lr : [<0000800c>]
>> > > sp : 0144b6e8  ip : 01000188     fp : 0144a6c8
>> > > r10: 00000000  r9 : 411fc090     r8 : 00000100
>> > > r7 : 00000cfb  r6 : 0144a6d0     r5 : 00000000  r4 : 00008000
>> > > r3 : 0000000c  r2 : 00000100     r1 : 00000cfb  r0 : 00000000
>> > > Flags: nZCv  IRQs off  FIQs off  Mode SVC_32
>> > > Resetting CPU ...
>> > > 
>> > > Signed-off-by: Marcel Ziswiler <marcel.ziswiler at toradex.com>
>> > > ---
>> > > Changes in v2:
>> > > Migrated to using generic bounce buffer implementation as
>suggested by
>> > > Simon.
>> > 
>> > I didn't see Simon's suggestion, but what is the general policy in
>U-Boot
>> > supposed to be for I/O alignment?  Responsibility of the API user,
>or of 
>> > the
>> > driver?  Are there other drivers with the same problem?
>> 
>> MMC has it. I feel that in general we should be able to ask the
>> higher-level systems to do the right thing and align their data.
>> Otherwise it introduces inefficiencies into the stack. But at least
>if
>> we do introduce this, we should use common infrastructure, hence my
>> request.
>
>OK, so your request wasn't to move this into the driver, just about how
>to 
>implement it if it's done in the driver?  Marcel, why did you change to
>
>handling this in the driver?

Maybe because U-Boot is deeply broken in that respect. Please also see my comment in my previous post.