[U-Boot] [v2 2/6] spi: cadence_qspi: remove sram polling from flash read

[Marek Vasut]

On Thursday, August 13, 2015 at 06:27:08 PM, vikasm wrote:
> Hi Marek,

Hi vikasm,

(you might want to fix your name in your mailer)

> On 08/12/2015 07:09 PM, Marek Vasut wrote:
> > On Thursday, July 16, 2015 at 04:27:30 AM, Vikas Manocha wrote:
> >> There is no need to check for sram fill level. If sram is empty, cpu
> >> will go in the wait state till the time data is available from flash.
> > 
> > Consider the following scenario:
> > - CPU core reads some memory area, but there are no data available just
> > yet
> > 
> >   => CPU core goes into wait state
> > 
> > - The data never arrive
> > 
> > Will the CPU be stuck forever ? If we checked the fill level first
> > instead, we would never enter such stuck-state.
> 
> This indirect mode of reading/writing would be entered when the read/write
> addresses are in the programmed valid range of addresses.
> 
> Even in case of "data never arrive" scenario, a simple timeout seems better
> then currently implemented read sram level with timeout.

How do you implement a "simple timeout" if the CPU core is stuck and does
not execute instructions ? If you mean interrupt, then forget it, U-Boot
does not do interrupts ;-)

Best regards,
Marek Vasut