Re: [U-Boot] [PATCH] overo: add SPL support

20 Dec 2011

      On Thursday, December 15, 2011 10:12:59 PM Andreas Müller wrote:
...
On Thu, Dec 15, 2011 at 7:34 AM, Andreas Müller schnitzeltony@gmx.de wrote:
...
I tried the following (as you can see I already commented out the
i2c-read-
write
...
for test):
int get_board_revision(void)
{
#ifdef CONFIG_DRIVER_OMAP34XX_I2C
   i2c_set_bus_num(TWL4030_I2C_BUS);
   /*data = 0x01;
   i2c_write(0x4B, 0x29, 1, &data, 1);
   data = 0x0c;
   i2c_write(0x4B, 0x2b, 1, &data, 1);
   i2c_read(0x4B, 0x2a, 1, &data, 1);*/

#endif
....
}
SPL Boot process hangs on i2c_set_bus_num ( tested by removing
i2c_set_bus_num -> proper operation ) with console freeze:
| U-Boot SPL 2011.12-rc1-00004-g06e42c6-dirty (Dec 15 2011 - 14:03:34)
| Texas Instruments Revision detection unimplemented
The call stack for get_board_revision() is for SPL
s_init()
mem_init()
do_sdrc_init(..)
get_board_mem_timings(..)
get_board_revision(..)
It seems that the call to i2c_set_bus_num comes too early.
Sorry for spamming but I face black magic:
I added debug messages in omap24xx_i2c.c / i2c_set_bus_num().

Version 1:

int i2c_set_bus_num(unsigned int bus)
{
   puts("i2c_set_bus_num called 1\n");
   if ((bus < 0) || (bus >= I2C_BUS_MAX)) {
   	printf("Bad bus: %d\n", bus);
   	return -1;
   }
   printf("Bus: %d\n", bus);
#if I2C_BUS_MAX == 3
   if (bus == 2) {
   	puts("i2c_set_bus_num called 2\n");
   	i2c_base = (struct i2c *)I2C_BASE3;
   	puts("i2c_set_bus_num called 3\n");
   }
   else
#endif
   if (bus == 1) {
   	puts("i2c_set_bus_num called 4\n");
   	i2c_base = (struct i2c *)I2C_BASE2;
   	puts("i2c_set_bus_num called 5\n");
   }
   else {
   	puts("i2c_set_bus_num called 6\n");
   	i2c_base = (struct i2c *)I2C_BASE1;
   	puts("i2c_set_bus_num called 7\n");
   }
puts("i2c_set_bus_num called 8\n");
-->	current_bus = bus;
puts("i2c_set_bus_num called 9\n");
   if (!bus_initialized[current_bus])
   	i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
return 0;
}
leads to
i2c_set_bus_num called 1
Bus: 0
i2c_set_bus_num called 6
i2c_set_bus_num called 7
i2c_set_bus_num called 8

Version 2:

int i2c_set_bus_num(unsigned int bus)
{
   puts("i2c_set_bus_num called 1\n");
   if ((bus < 0) || (bus >= I2C_BUS_MAX)) {
   	printf("Bad bus: %d\n", bus);
   	return -1;
   }
   printf("Bus: %d\n", bus);
-->	printf("CurrentBus: %d\n", current_bus);
   printf("AdrCurrentBus: %X\n", &current_bus);
#if I2C_BUS_MAX == 3
   if (bus == 2) {
   	puts("i2c_set_bus_num called 2\n");
   	i2c_base = (struct i2c *)I2C_BASE3;
   	puts("i2c_set_bus_num called 3\n");
   }
   else
#endif
   if (bus == 1) {
   	puts("i2c_set_bus_num called 4\n");
   	i2c_base = (struct i2c *)I2C_BASE2;
   	puts("i2c_set_bus_num called 5\n");
   }
   else {
   	puts("i2c_set_bus_num called 6\n");
   	i2c_base = (struct i2c *)I2C_BASE1;
   	puts("i2c_set_bus_num called 7\n");
   }
puts("i2c_set_bus_num called 8\n");
   current_bus = bus;
puts("i2c_set_bus_num called 9\n");
   if (!bus_initialized[current_bus])
   	i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
return 0;
}
leads to
i2c_set_bus_num called 1
Bus: 0
It seems that accessing 'current_bus' causes trouble. Has anybody an
explanation for that? I don't think this is related to i2c or overo. For a
better picture I attached memory mappings.
'objdump -dSt' shows (the memory mappings I attached were not really helpful - 
sorry next time I know):
4020ae14 l     O .data      00000004 i2c_base
    80000068 l     O .bss       00000004 current_bus
    8000006c l     O .bss       0000000c bus_initialized
'i2c_base' is correctly located in SRAM but 'current_bus' and 'bus_initialized' 
are located in CS0 SDRAM which is at the time of call not yet initalized. This 
fits to the crash behaviour: Accessing 'i2c_base' does not cause trouble.
How can I move 'current_bus' and 'bus_initialized' to SRAM?
Andreas