Hi Simon,
On 22/12/11 17:44, Simon Glass wrote:
> Hi Graeme,
>
> On Tue, Dec 20, 2011 at 4:06 AM, Graeme Russ <graeme.r...@gmail.com> wrote:
>> With Simon's work on generic relocation support, I thought I would throw in
>> what I am planning for arch/x86/lib/board.c
>>
>> Now this is not a patch, it is a work-in-progress complete version of the
>> file (compiles, will test soon) - If feedback is positive, I'll add this to
>> an upcoming patch set
>
> Looks good to me+++
Thanks for having a look :)
>> Notice the amount of wrapping around void functions - If all other arch's
>> follow this lead, most of this wrapping can be removed by changing the
>> function signatures.
>>
>> Lines 428 - 585 are effectively the generic init sequence - The rest is
>> wrappers, init sequence arrays, or fluff that should be moved
>>
>> I noticed something along the way - gd is no longer special... let me
>> explain...
>>
>> Some arch's use a dedicated register for the gd pointer - This allows the
>> pointer to be written to prior to relocation. For x86, the gd pointer is
>> simply passed around as a function parameter early - If the init_sequence_f
>> functions accepted a gd pointer as a parameter, there would be no need for
>> it to be global prior to relocation and therefore no need to allocate a
>> permanent register for it - Of course do_init_loop() would no longer be
>> generic for both pre and post relocation. This does mess with the
>> stand-alone API, but as discussed before, stand alone applications should
>> not be accessing gd anyway, so there should be no API to break ;)
>
> Actually as it happens I did a bit of an experiment with this some
> weeks ago and my original board stuff had gd as a parameter for the
> pre-reloc functions (some with stubs to other ones like
> console_init_f()). On ARM it really doesn't make a lot of sense to use
> a global variable instead of a parameter. I decided that it was a bit
> much to bite off in one go :-) Partly that was because IMO gd really
> only makes sense prior to relocation - for the post-relocation init
> calls they don't have a lot of need for gd.
I don't think this is 100% correct - I'm sure gd is used all over the place
post init
> So it has my vote. Once I get somewhere on the reboard series I will
> post my common/board.c. As I may have mentioned I have elected so far
> to leave the initcall list and local functions in
> arch/xxx/lib/board.c.
>
> Would be good to get all this moving.
Well, I have a more thorough patch in the making - I creates
init_wrappers.c and init_helpers.c and board.c collapses very dramatically
(see below) - with a lot of #ifdef hell...
Notice the new board_init_f_r() - This is where U-Boot is running from
Flash, but SDRAM has been initialised and the stack is now in RAM - So this
is where we move gd to RAM and perform relocation. As a bonus, relocation
can be done with cache enabled :)
Regards,
Graeme
/*
* (C) Copyright 2008-2011
* Graeme Russ, <graeme.r...@gmail.com>
*
* (C) Copyright 2002
* Daniel Engström, Omicron Ceti AB, <dan...@omicron.se>
*
* (C) Copyright 2002
* Wolfgang Denk, DENX Software Engineering, <w...@denx.de>
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Marius Groeger <mgroe...@sysgo.de>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <watchdog.h>
#include <stdio_dev.h>
#include <asm/u-boot-x86.h>
#include <asm/init_helpers.h>
#include <asm/init_wrappers.h>
/*
* Pointer to initial global data area
*
* Here we initialize it.
*/
#undef XTRN_DECLARE_GLOBAL_DATA_PTR
#define XTRN_DECLARE_GLOBAL_DATA_PTR /* empty = allocate here */
DECLARE_GLOBAL_DATA_PTR = (gd_t *) (CONFIG_SYS_INIT_GD_ADDR);
/*
* Breath some life into the board...
*
* Initialize an SMC for serial comms, and carry out some hardware
* tests.
*
* The first part of initialization is running from Flash memory;
* its main purpose is to initialize the RAM so that we
* can relocate the monitor code to RAM.
*/
/*
* All attempts to come up with a "common" initialization sequence
* that works for all boards and architectures failed: some of the
* requirements are just _too_ different. To get rid of the resulting
* mess of board dependend #ifdef'ed code we now make the whole
* initialization sequence configurable to the user.
*
* The requirements for any new initalization function is simple: it
* receives a pointer to the "global data" structure as it's only
* argument, and returns an integer return code, where 0 means
* "continue" and != 0 means "fatal error, hang the system".
*/
typedef int (init_fnc_t) (void);
init_fnc_t *init_sequence_f[] = {
cpu_init_f,
board_early_init_f,
env_init,
init_baudrate_f,
serial_init,
console_init_f,
dram_init_f,
NULL,
};
init_fnc_t *init_sequence_r[] = {
init_bd_struct_r,
mem_malloc_init_r,
cpu_init_r,
board_early_init_r,
dram_init,
interrupt_init,
timer_init,
display_banner,
display_dram_config,
#ifdef CONFIG_SERIAL_MULTI
serial_initialize_r,
#endif
#ifndef CONFIG_SYS_NO_FLASH
flash_init_r,
#endif
env_relocate_r,
#ifdef CONFIG_CMD_NET
init_ip_address_r,
#endif
#ifdef CONFIG_PCI
pci_init_r,
#endif
stdio_init,
jumptable_init_r,
console_init_r,
#ifdef CONFIG_MISC_INIT_R
misc_init_r,
#endif
#if defined(CONFIG_CMD_PCMCIA) && !defined(CONFIG_CMD_IDE)
pci_init_r,
#endif
#if defined(CONFIG_CMD_KGDB)
kgdb_init_r,
#endif
enable_interrupts_r,
#ifdef CONFIG_STATUS_LED
status_led_set_r,
#endif
set_load_addr_r,
#if defined(CONFIG_CMD_NET)
set_bootfile_r,
#endif
#if defined(CONFIG_CMD_IDE)
ide_init_r,
#endif
#if defined(CONFIG_CMD_SCSI)
scsi_init_r,
#endif
#if defined(CONFIG_CMD_DOC)
doc_init_r,
#endif
#ifdef CONFIG_BITBANGMII
bb_miiphy_init_r,
#endif
#if defined(CONFIG_CMD_NET)
eth_initialize_r,
#ifdef CONFIG_RESET_PHY_R
reset_phy_r,
#endif
#endif
#ifdef CONFIG_LAST_STAGE_INIT
last_stage_init,
#endif
NULL,
};
static void do_init_loop(init_fnc_t **init_fnc_ptr)
{
for (; *init_fnc_ptr; ++init_fnc_ptr) {
WATCHDOG_RESET();
if ((*init_fnc_ptr)() != 0)
hang();
}
}
/* Perform all steps necessary to get RAM initialised ready for relocation */
void board_init_f(ulong boot_flags)
{
gd->flags = boot_flags;
do_init_loop(init_sequence_f);
/*
* SDRAM is now initialised setup a new stack in SDRAM
*
* Code execution will continue in Flash, but with the stack
* in SDRAM. This allows us to copy global data out of the CPU
* cache prior to copying U-Boot into RAM which means we can
* enable caching for the copy operation (which speeds it up
* considerably)
*/
move_stack_to_sdram(gd->ram_size);
/* NOTREACHED - move_stack_to_sdram() does not return */
while (1)
;
}
void board_init_f_r(gd_t *id)
{
/*
* U-Boot is running from flash, but the stack is now in SDRAM
* (id = top of stack = final location of global data)
*/
/*
* gd is still in CAR - Copy it into SDRAM
*
* NOTE: We cannot set the gd variable yet as it lives in .data
* which has not been relocated to RAM yet
*/
memcpy(id, gd, sizeof(gd_t));
/* Initialise the CPU cache(s) */
if (init_cache() != 0)
hang();
/* Copy U-Boot to RAM and resume code execution in RAM */
relocate_code(0, id, 0);
/* NOTREACHED - relocate_code() does not return */
while (1)
;
}
__attribute__ ((__noreturn__))
void board_init_r(gd_t *id, ulong dest_addr)
{
/* Global data pointer is now writable */
gd = id;
gd->flags |= GD_FLG_RELOC;
/* compiler optimization barrier needed for GCC >= 3.4 */
__asm__ __volatile__("" : : : "memory");
do_init_loop(init_sequence_r);
/* main_loop() can return to retry autoboot, if so just run it again. */
for (;;)
main_loop();
/* NOTREACHED - no way out of command loop except booting */
}
__attribute__ ((__noreturn__))
void hang(void)
{
puts("### ERROR ### Please RESET the board ###\n");
for (;;)
;
}
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