Re: mtd: rawnand: fsmc: Keep bank enable bit set

[Boris Brezillon <bbrezillon@xxxxxxxxxx>]

On Wed, 2019-01-09 at 21:51:44 UTC, Linus Walleij wrote:
> Hammering the "bank enable" (PBKEN) bit on and off between
> every command crashes the Nomadik NHK15 with this message:
> 
> Scanning device for bad blocks
> Unhandled fault: external abort on non-linefetch (0x008) at 0xcc95e000
> pgd = (ptrval)
> [cc95e000] *pgd=0b808811, *pte=40000653, *ppte=40000552
> Internal error: : 8 [#1] PREEMPT ARM
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper Not tainted 4.20.0-rc2+ #72
> Hardware name: Nomadik STn8815
> PC is at fsmc_exec_op+0x194/0x204
> (...)
> 
> After a discussion we (me and Boris Brezillion) start to suspect
> that this bit does not immediately control the chip select line
> at all, it rather enables access to the bank and the hardware
> will drive the CS autonomously. If there is a NAND chip connected,
> we should keep this enabled.
> 
> As fsmc_nand_setup() sets this bit, we can simply remove the
> offending code.
> 
> Fixes: 550b9fc4e3af ("mtd: rawnand: fsmc: Stop implementing ->select_chip()")
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Reviewed-by: Boris Brezillon <bbrezillon@xxxxxxxxxx>
> Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>

Applied to http://git.infradead.org/linux-mtd.git mtd/fixes, thanks.

Boris

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