[U-Boot] common/xyzmodem.c, ymodem, slow behavior receiving bytes

[Angelo Dureghello]

On Mon, Nov 19, 2012 at 11:58:24PM +0100, Wolfgang Denk wrote:

Dear Wolfgang and All,

> I'm glad my initial suspicions were right.  Can you please post some
> hints / patches what needs to be fixed, and where?

Sorry for the late reply. I damaged a gpio port of the board and still
re-soldering a better one for my tests.

Issues was related to my "board.h" only, and maybe related to mcf5307 support, 
that i am trying add to u-boot.

mcf5307 seems to have someway a special case for the cache.
It has a 8KB unified instruction+data cache, that seems to be the same, and 
this is quite oddly, of V.2 mcf5249.

As a first point, my board.h was not configuring any sdram cache-enabled 
address area. This was probably causing a very slow non-cached code execution
and non-cached data read/write. In this case execution is a bit faster changing
-Os to -O2.

So i enabled the sdram cache with:

#define CONFIG_SYS_CACHELINE_SIZE	16

#define ICACHE_STATUS			(CONFIG_SYS_INIT_RAM_ADDR + \
					 CONFIG_SYS_INIT_RAM_SIZE - 8)
#define DCACHE_STATUS			(CONFIG_SYS_INIT_RAM_ADDR + \
					 CONFIG_SYS_INIT_RAM_SIZE - 4)
#define CONFIG_SYS_ICACHE_INV           (CF_CACR_CINVA)
#define CONFIG_SYS_CACHE_ACR0		(CF_ACR_CM_WT | CF_ACR_SM_ALL | \
					 CF_ACR_EN)
#define CONFIG_SYS_CACHE_ICACR		(CF_CACR_DCM_P | CF_CACR_ESB | \
					 CF_CACR_EC)

Still, had to use "write-through", becouse "copyback" need also a "flush"
(m68k "cpushl") that is still not iplemented in u-boot for m68k 
(it seems to be a to-do). 

Finally, i had to remove every mask from ACR (CF_ADDRMASK(x) macro) since
was causing for my case a complete block after cache initialization.
For this, i looked uClinu cache init, but still have to understand
clearly why the mask setup block the boot.
I will clarify this as soon i have a new board running and will post back.

Best Regards,
Angelo Dureghello