[U-Boot] ARM: OMAP5: Fix warm reset with USB cable connected

[Tom Rini]

On Wed, Apr 17, 2013 at 08:49:40PM -0000, Lokesh Vutla wrote:

> Warm reset on OMAP5 freezes when USB cable is connected.
> Fix requires PRM_RSTTIME.RSTTIME1 to be programmed
> with the time for which reset should be held low for the
> voltages and the oscillator to reach stable state.
> 
> There are 3 parameters to be considered for calculating
> the time, which are mostly board and PMIC dependent.
> -1- Time taken by the Oscillator to shut + restart
> -2- PMIC OTP times
> -3- Voltage rail ramp times, which inturn depends on the
> PMIC slew rate and value of the voltage ramp needed.
> 
> In order to keep the code in u-boot simple, have a way
> for boards to specify a pre computed time directly using
> the 'CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC'
> option. If boards fail to specify the time, use a default
> as specified by 'CONFIG_DEFAULT_OMAP_RESET_TIME_MAX_USEC' instead.
> Using the default value translates into some ~22ms and should work in
> all cases.
> However in order to avoid this large delay hiding other bugs,
> its recommended that all boards look at their respective data
> sheets and specify a pre computed and optimal value using
> 'CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC'
> 
> In order to help future board additions to compute this
> config option value, add a README at doc/README.omap-reset-time
> which explains how to compute the value. Also update the toplevel
> README with the additional option and pointers to
> doc/README.omap-reset-time.
> 
> Signed-off-by: Lokesh Vutla <lokeshvutla at ti.com>
> [rnayak at ti.com: Updated changelog and added the README]
> Signed-off-by: Rajendra Nayak <rnayak at ti.com>

Applied to u-boot-ti/master, thanks!

-- 
Tom
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