[U-Boot-Users] RE: [PATCH] OMAP242x/H4 board updates.

Woodruff, Richard r-woodruff2 at ti.com
Fri Mar 4 13:04:05 CET 2005

> > 	- unlock SRAM for GP devices.
> AFAIK, GP devices are configured at chip level, means,
> it depends on what chip I had received. _or_ will it
> be possible to to configure EVM for to access full

For the device types you may use (GP/HS/EMU) all but a small portion of
the SRAM comes up in a locked mode for an external boot.  A GP device
can directly hit HW firewall registers to open it all up.  For internal
boot using a signed image the secure mask ROM code will unlock SRAM for
the ARM11, but not other initiators (DSP/IVA/...).  To get SRAM in this
mode you need to make a call into secure mode to affect the HW firewall
registers. There are a couple ways to get code to run in secure mode,
but require some specific procedures.

> As per our obeservations codecs like software had
> significant performance running in IVA when access to
> SDRAM from ARM11 is less...meaning let's put part of
> continously running Linux code in SRAM and reduce
> SDRAM contention.

This may be true. The SDRAM is a shared resource.  I would think making
sure priorities are mapped correctly to the SMS at the initiator level
would mitigate this.  ES2 has several fix ups to defaults which should
make performance better across the board.  The next 24xx has further
fixes to increase performance.

Richard W.

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