| Message ID | 4DF617C2.6070100@ti.com |
|---|---|
| State | Not Applicable |
| Headers | show |
Dear Wolfgang, Heiko, On Monday 13 June 2011 07:29 PM, Aneesh V wrote: > Dear Wolfgang, [snip ...] > But this didn't work. It crashes at the first printf(). The reason is > init_baudrate() needs global data and global data is initialized in > board_init_f(). Further, we can not move global data initialization > earlier because for global data we reuse low level stack used by > lowlevel_init(). > > gd = (gd_t *) ((CONFIG_SYS_INIT_SP_ADDR) & ~0x07); On second thoughts I realize that the stack in internal RAM is still in use in board_init_f(). So, how does this work at all? The global data and the stack seems to be overlapping! Please note the register dump after the above instruction. Note that R8(gd) and R13(sp) are very close. N _ R0 0 R8 4030DF80 SP> 12345678 Z Z R1 0A R9 12345678 -04 80E80078 C C R2 4030DED4 R10 40304350 FP> D78772CA V _ R3 5555 R11 0002FE40 +04 4049A39E I I R4 0 R12 80E80068 +08 F5A73CF4 F F R5 10 R13 4030DF78 +0C 7B317D39 T _ R6 12345678 R14 80E80078 +10 ED3CFCF0 J _ R7 12345678 PC 80E80880 +14 FEECEC6A svc SPSR 0 CPSR 600001D3 +18 6DB22EB2 Am I missing something? best regards, Aneesh
Dear Aneesh V, In message <4DF617C2.6070100@ti.com> you wrote: > > > Console should _always_ be enabled as early as possible, > > Unfortunately this is not the case with U-Boot today. Console > initialization happens in board_init_f(). Before board_init_f() > typically a lot of(in fact most of) low level initialization happens > through the lowlevel_init() function called from start.S and the > initial part of init_sequence() As the name LOWLEVEL_init() suggests, this is suppoed to contain always only the bare minimum of initialization that is necessary to get the CPU running. All more complex initializations should be delayed and only be run when we have a proper environment, including debug output on the console. > > Can we not rather change the code so both configurations behave the > > same? > > In SPL I had more flexibility, so I do a simplified init of console > right at the beginning of lowlevel_init(), so I can use debug prints in > lowlevel_init(). Some part of our lowlevel_init() that is executed in > SPL path may also be executed by U-Boot if it runs from NOR flash, but > in this case console wouldn't be ready. That's why I made the macro. I do not understand this. How can you have more flexibility in the more restricted environment? We definitely should unify this. > No. That wouldn't serve the purpose. I need two macros to distinguish > between the two cases. > 1. 'debug()' - can be used in all places at which console is guaranteed > to be initialized whether executed as part of U-Boot or SPL. > 2. 'spl_debug()' to be used at places where console is initialized for > SPL but not for U-Boot (eg. lowlevel_init()) - so emit no code for > U-Boot. You see - this distinction is becoming a mess. Let's get rid of this and use common code for both cases. Best regards, Wolfgang Denk
Dear Wolfgang, On Wednesday 15 June 2011 03:48 PM, Wolfgang Denk wrote: > Dear Aneesh V, > [snip ..] >> No. That wouldn't serve the purpose. I need two macros to distinguish >> between the two cases. >> 1. 'debug()' - can be used in all places at which console is guaranteed >> to be initialized whether executed as part of U-Boot or SPL. >> 2. 'spl_debug()' to be used at places where console is initialized for >> SPL but not for U-Boot (eg. lowlevel_init()) - so emit no code for >> U-Boot. > > You see - this distinction is becoming a mess. Let's get rid of this > and use common code for both cases. I replaced spl_debug() with debug() now. I moved sdram_init() out of lowlevel_init() for u-boot so that console is available by the time sdram_init() runs. However, clock init needs to remain in lowlevel_init() and I still feel that some debug traces from this module will be a good debugging tool for SPL, so I retained the traces and added something like this in arch/arm/cpu/armv7/omap4/clocks.c: /* * printing to console doesn't work unless * this code is executed from SPL */ #ifndef CONFIG_PRELOADER #define printf(fmt, args...) #define puts(s) #endif Is that fine? best regards, Aneesh
diff --git a/arch/arm/cpu/armv7/omap4/board.c b/arch/arm/cpu/armv7/omap4/board.c index fcd29a7..56902e3 100644 --- a/arch/arm/cpu/armv7/omap4/board.c +++ b/arch/arm/cpu/armv7/omap4/board.c @@ -41,6 +41,7 @@ DECLARE_GLOBAL_DATA_PTR; */ void s_init(void) { + printf("Hello World!!\n"); watchdog_init(); } diff --git a/arch/arm/cpu/armv7/omap4/lowlevel_init.S b/arch/arm/cpu/armv7/omap4/lowlevel_init.S index 026dfa4..42264b2 100644 --- a/arch/arm/cpu/armv7/omap4/lowlevel_init.S +++ b/arch/arm/cpu/armv7/omap4/lowlevel_init.S @@ -31,17 +31,6 @@ .globl lowlevel_init lowlevel_init: /* - * Setup a temporary stack - */ - ldr sp, =LOW_LEVEL_SRAM_STACK - - /* - * Save the old lr(passed in ip) and the current lr to stack - */ - push {ip, lr} - - /* * go setup pll, mux, memory */ - bl s_init - pop {ip, pc} + b s_init diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S index d91ae12..4a9251f 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -307,10 +307,11 @@ cpu_init_crit: * basic memory. Go here to bump up clock rate and handle * wake up conditions. */ - mov ip, lr @ persevere link reg across call + ldr sp, =CONFIG_SYS_INIT_SP_ADDR + push {lr} + bl early_console_init bl lowlevel_init @ go setup pll,mux,memory - mov lr, ip @ restore link - mov pc, lr @ back to my caller + pop {pc} /* ************************************************************************* * diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c index 1a784a1..0c696c2 100644 --- a/arch/arm/lib/board.c +++ b/arch/arm/lib/board.c @@ -248,9 +248,6 @@ init_fnc_t *init_sequence[] = { get_clocks, #endif env_init, /* initialize environment */ - init_baudrate, /* initialze baudrate settings */ - serial_init, /* serial communications setup */ - console_init_f, /* stage 1 init of console */ display_banner, /* say that we are here */ #if defined(CONFIG_DISPLAY_CPUINFO) print_cpuinfo, /* display cpu info (and speed) */ @@ -268,6 +265,13 @@ init_fnc_t *init_sequence[] = { NULL, }; +void early_console_init(void) +{ + init_baudrate(); /* initialze baudrate settings */ + serial_init(); /* serial communications setup */ + console_init_f(); /* stage 1 init of console */ +} + void board_init_f (ulong bootflag) { bd_t *bd;