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

["Andreas Müller" <schnitzeltony@gmx.de>]

On Thursday, December 15, 2011 10:12:59 PM Andreas M?ller wrote:
> On Thu, Dec 15, 2011 at 7:34 AM, Andreas M?ller <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