[U-Boot,17/17] x86: Tweak initialisation procedure

Signed-off-by: Graeme Russ <graeme.russ@gmail.com>
---
 arch/x86/include/asm/init_helpers.h |    5 +
 arch/x86/include/asm/relocate.h     |   33 ++++++
 arch/x86/lib/board.c                |  188 +++++++++++++++++------------------
 arch/x86/lib/init_helpers.c         |   75 ++++++++++++++
 arch/x86/lib/relocate.c             |   32 +-----
 5 files changed, 206 insertions(+), 127 deletions(-)
 create mode 100644 arch/x86/include/asm/relocate.h

Hi Graeme,

On Sun, Jan 1, 2012 at 8:09 PM, Graeme Russ <graeme.russ@gmail.com> wrote:
>
> Signed-off-by: Graeme Russ <graeme.russ@gmail.com>
> ---
>  arch/x86/include/asm/init_helpers.h |    5 +
>  arch/x86/include/asm/relocate.h     |   33 ++++++
>  arch/x86/lib/board.c                |  188 +++++++++++++++++------------------
>  arch/x86/lib/init_helpers.c         |   75 ++++++++++++++
>  arch/x86/lib/relocate.c             |   32 +-----
>  5 files changed, 206 insertions(+), 127 deletions(-)

Seems like a fairly major tweak :-) Should this commit be split,
and/or perhaps explain the purpose in the commit message?

Regards,
Simon

>  create mode 100644 arch/x86/include/asm/relocate.h
>
> diff --git a/arch/x86/include/asm/init_helpers.h b/arch/x86/include/asm/init_helpers.h
> index 14ef11a..192f18e 100644
> --- a/arch/x86/include/asm/init_helpers.h
> +++ b/arch/x86/include/asm/init_helpers.h
> @@ -27,7 +27,12 @@
>  int display_banner(void);
>  int display_dram_config(void);
>  int init_baudrate_f(void);
> +int calculate_relocation_address(void);
>
> +int copy_gd_to_ram_f_r(void);
> +int init_cache_f_r(void);
> +
> +int set_reloc_flag_r(void);
>  int mem_malloc_init_r(void);
>  int init_bd_struct_r(void);
>  int flash_init_r(void);
> diff --git a/arch/x86/include/asm/relocate.h b/arch/x86/include/asm/relocate.h
> new file mode 100644
> index 0000000..33129ef
> --- /dev/null
> +++ b/arch/x86/include/asm/relocate.h
> @@ -0,0 +1,33 @@
> +/*
> + * (C) Copyright 2011
> + * Graeme Russ, <graeme.russ@gmail.com>
> + *
> + * 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
> + */
> +
> +#ifndef _RELOCATE_H_
> +#define _RELOCATE_H_
> +
> +#include <common.h>
> +
> +int copy_uboot_to_ram(void);
> +int clear_bss(void);
> +int do_elf_reloc_fixups(void);
> +
> +#endif /* !_RELOCATE_H_ */
> diff --git a/arch/x86/lib/board.c b/arch/x86/lib/board.c
> index f0a8e9c..d45b8fd 100644
> --- a/arch/x86/lib/board.c
> +++ b/arch/x86/lib/board.c
> @@ -35,7 +35,7 @@
>  #include <watchdog.h>
>  #include <stdio_dev.h>
>  #include <asm/u-boot-x86.h>
> -#include <asm/processor.h>
> +#include <asm/relocate.h>
>
>  #include <asm/init_helpers.h>
>  #include <asm/init_wrappers.h>
> @@ -43,31 +43,58 @@
>  /*
>  * Breath some life into the board...
>  *
> - * Initialize an SMC for serial comms, and carry out some hardware
> - * tests.
> + * Getting the board up and running is a three-stage process:
> + *  1) Execute from Flash, SDRAM Uninitialised
> + *     At this point, there is a limited amount of non-SDRAM memory
> + *     (typically the CPU cache, but can also be SRAM or even a buffer of
> + *     of some peripheral). This limited memory is used to hold:
> + *      - The initial copy of the Global Data Structure
> + *      - A temporary stack
> + *      - A temporary x86 Global Descriptor Table
> + *      - The pre-console buffer (if enabled)
>  *
> - * 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.
> + *     The following is performed during this phase of execution:
> + *      - Core low-level CPU initialisation
> + *      - Console initialisation
> + *      - SDRAM initialisation
> + *
> + *  2) Execute from Flash, SDRAM Initialised
> + *     At this point we copy Global Data from the initial non-SDRAM
> + *     memory and set up the permanent stack in SDRAM. The CPU cache is no
> + *     longer being used as temporary memory, so we can now fully enable
> + *     it.
> + *
> + *     The following is performed during this phase of execution:
> + *      - Create final stack in SDRAM
> + *      - Copy Global Data from temporary memory to SDRAM
> + *      - Enabling of CPU cache(s),
> + *      - Copying of U-Boot code and data from Flash to RAM
> + *      - Clearing of the BSS
> + *      - ELF relocation adjustments
> + *
> + *  3) Execute from SDRAM
> + *     The following is performed during this phase of execution:
> + *      - All remaining initialisation
>  */
>
>  /*
> - * 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".
> + * The requirements for any new initalization function is simple: it is
> + * a function with no parameters which returns an integer return code,
> + * where 0 means "continue" and != 0 means "fatal error, hang the system"
>  */
>  typedef int (init_fnc_t) (void);
>
> -static int calculate_relocation_address(void);
> -static int copy_gd_to_ram(void);
> -
> +/*
> + * init_sequence_f is the list of init functions which are run when U-Boot
> + * is executing from Flash with a limited 'C' environment. The following
> + * limitations must be considered when implementing an '_f' function:
> + *  - 'static' variables are read-only
> + *  - Global Data (gd->xxx) is read/write
> + *  - Stack space is limited
> + *
> + * The '_f' sequence must, as a minimum, initialise SDRAM. It _should_
> + * also initialise the console (to provide early debug output)
> + */
>  init_fnc_t *init_sequence_f[] = {
>        cpu_init_f,
>        board_early_init_f,
> @@ -81,7 +108,39 @@ init_fnc_t *init_sequence_f[] = {
>        NULL,
>  };
>
> +/*
> + * init_sequence_f_r is the list of init functions which are run when
> + * U-Boot is executing from Flash with a semi-limited 'C' environment.
> + * The following limitations must be considered when implementing an
> + * '_f_r' function:
> + *  - 'static' variables are read-only
> + *  - Global Data (gd->xxx) is read/write
> + *
> + * The '_f_r' sequence must, as a minimum, copy U-Boot to RAM (if
> + * supported).  It _should_, if possible, copy global data to RAM and
> + * initialise the CPU caches (to speed up the relocation process)
> + */
> +init_fnc_t *init_sequence_f_r[] = {
> +       copy_gd_to_ram_f_r,
> +       init_cache_f_r,
> +       copy_uboot_to_ram,
> +       clear_bss,
> +       do_elf_reloc_fixups,
> +
> +       NULL,
> +};
> +
> +/*
> + * init_sequence_r is the list of init functions which are run when U-Boot
> + * is executing from RAM with a full 'C' environment. There are no longer
> + * any limitations which must be considered when implementing an '_r'
> + * function, (i.e.'static' variables are read/write)
> + *
> + * If not already done, the '_r' sequence must copy global data to RAM and
> + * (should) initialise the CPU caches.
> + */
>  init_fnc_t *init_sequence_r[] = {
> +       set_reloc_flag_r,
>        init_bd_struct_r,
>        mem_malloc_init_r,
>        cpu_init_r,
> @@ -157,54 +216,14 @@ static void do_init_loop(init_fnc_t **init_fnc_ptr)
>        }
>  }
>
> -static int calculate_relocation_address(void)
> -{
> -       ulong text_start = (ulong)&__text_start;
> -       ulong bss_end = (ulong)&__bss_end;
> -       ulong dest_addr;
> -
> -       /*
> -        * NOTE: All destination address are rounded down to 16-byte
> -        *       boundary to satisfy various worst-case alignment
> -        *       requirements
> -        */
> -
> -       /* Global Data is at top of available memory */
> -       dest_addr = gd->ram_size;
> -       dest_addr -= GENERATED_GBL_DATA_SIZE;
> -       dest_addr &= ~15;
> -       gd->new_gd_addr = dest_addr;
> -
> -       /* GDT is below Global Data */
> -       dest_addr -= GDT_SIZE;
> -       dest_addr &= ~15;
> -       gd->gdt_addr = dest_addr;
> -
> -       /* Stack is below GDT */
> -       gd->start_addr_sp = dest_addr;
> -
> -       /* U-Boot is below the stack */
> -       dest_addr -= CONFIG_SYS_STACK_SIZE;
> -       dest_addr -= (bss_end - text_start);
> -       dest_addr &= ~15;
> -       gd->relocaddr = dest_addr;
> -       gd->reloc_off = (dest_addr - text_start);
> -
> -       return 0;
> -}
> -
> -/* 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, U-Boot has been copied into SDRAM,
> -        * the BSS has been cleared etc. The final stack can now be setup
> -        * in SDRAM. Code execution will continue (momentarily) in Flash,
> -        * but with the stack in SDRAM and Global Data in temporary memory
> +        * SDRAM and console are now initialised. The final stack can now
> +        * be setup in SDRAM. Code execution will continue in Flash, but
> +        * with the stack in SDRAM and Global Data in temporary memory
>         * (CPU cache)
>         */
>        board_init_f_r_trampoline(gd->start_addr_sp);
> @@ -216,51 +235,22 @@ void board_init_f(ulong boot_flags)
>
>  void board_init_f_r(void)
>  {
> -       if (copy_gd_to_ram() != 0)
> -               hang();
> -
> -       if (init_cache() != 0)
> -               hang();
> -
> -       relocate_code(0, gd, 0);
> -
> -       /* NOTREACHED - relocate_code() does not return */
> -       while (1)
> -               ;
> -}
> -
> -static int copy_gd_to_ram(void)
> -{
> -       gd_t *ram_gd;
> +       do_init_loop(init_sequence_f_r);
>
>        /*
> -        * Global data is still in temporary memory (the CPU cache).
> -        * calculate_relocation_address() has set gd->new_gd_addr to
> -        * where the global data lives in RAM but getting it there
> -        * safely is a bit tricky due to the 'F-Segment Hack' that
> -        * we need to use for x86
> +        * U-Boot has been copied into SDRAM, the BSS has been cleared etc.
> +        * Transfer execution from Flash to RAM by calculating the address
> +        * of the in-RAM copy of board_init_r() and calling it
>         */
> -       ram_gd = (gd_t *)gd->new_gd_addr;
> -       memcpy((void *)ram_gd, gd, sizeof(gd_t));
> +       (board_init_r + gd->reloc_off)(gd, gd->relocaddr);
>
> -       /*
> -        * Reload the Global Descriptor Table so FS points to the
> -        * in-RAM copy of Global Data (calculate_relocation_address()
> -        * has already calculated the in-RAM location of the GDT)
> -        */
> -       ram_gd->gd_addr = (ulong)ram_gd;
> -       init_gd(ram_gd, (u64 *)gd->gdt_addr);
> -
> -       return 0;
> +       /* NOTREACHED - board_init_r() does not return */
> +       while (1)
> +               ;
>  }
>
>  void board_init_r(gd_t *id, ulong dest_addr)
>  {
> -       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. */
> diff --git a/arch/x86/lib/init_helpers.c b/arch/x86/lib/init_helpers.c
> index 547b180..acc825b 100644
> --- a/arch/x86/lib/init_helpers.c
> +++ b/arch/x86/lib/init_helpers.c
> @@ -29,6 +29,7 @@
>  #include <ide.h>
>  #include <serial.h>
>  #include <status_led.h>
> +#include <asm/processor.h>
>  #include <asm/u-boot-x86.h>
>
>  #include <asm/init_helpers.h>
> @@ -70,6 +71,80 @@ int init_baudrate_f(void)
>        return 0;
>  }
>
> +int calculate_relocation_address(void)
> +{
> +       ulong text_start = (ulong)&__text_start;
> +       ulong bss_end = (ulong)&__bss_end;
> +       ulong dest_addr;
> +
> +       /*
> +        * NOTE: All destination address are rounded down to 16-byte
> +        *       boundary to satisfy various worst-case alignment
> +        *       requirements
> +        */
> +
> +       /* Global Data is at top of available memory */
> +       dest_addr = gd->ram_size;
> +       dest_addr -= GENERATED_GBL_DATA_SIZE;
> +       dest_addr &= ~15;
> +       gd->new_gd_addr = dest_addr;
> +
> +       /* GDT is below Global Data */
> +       dest_addr -= GDT_SIZE;
> +       dest_addr &= ~15;
> +       gd->gdt_addr = dest_addr;
> +
> +       /* Stack is below GDT */
> +       gd->start_addr_sp = dest_addr;
> +
> +       /* U-Boot is below the stack */
> +       dest_addr -= CONFIG_SYS_STACK_SIZE;
> +       dest_addr -= (bss_end - text_start);
> +       dest_addr &= ~15;
> +       gd->relocaddr = dest_addr;
> +       gd->reloc_off = (dest_addr - text_start);
> +
> +       return 0;
> +}
> +
> +int copy_gd_to_ram_f_r(void)
> +{
> +       gd_t *ram_gd;
> +
> +       /*
> +        * Global data is still in temporary memory (the CPU cache).
> +        * calculate_relocation_address() has set gd->new_gd_addr to
> +        * where the global data lives in RAM but getting it there
> +        * safely is a bit tricky due to the 'F-Segment Hack' that
> +        * we need to use for x86
> +        */
> +       ram_gd = (gd_t *)gd->new_gd_addr;
> +       memcpy((void *)ram_gd, gd, sizeof(gd_t));
> +
> +       /*
> +        * Reload the Global Descriptor Table so FS points to the
> +        * in-RAM copy of Global Data (calculate_relocation_address()
> +        * has already calculated the in-RAM location of the GDT)
> +        */
> +       ram_gd->gd_addr = (ulong)ram_gd;
> +       init_gd(ram_gd, (u64 *)gd->gdt_addr);
> +
> +       return 0;
> +}
> +
> +int init_cache_f_r(void)
> +{
> +       /* Initialise the CPU cache(s) */
> +       return init_cache();
> +}
> +
> +int set_reloc_flag_r(void)
> +{
> +       gd->flags = boot_flags;
> +
> +       return 0;
> +}
> +
>  int mem_malloc_init_r(void)
>  {
>        mem_malloc_init(((gd->relocaddr - CONFIG_SYS_MALLOC_LEN)+3)&~3,
> diff --git a/arch/x86/lib/relocate.c b/arch/x86/lib/relocate.c
> index badb5f8..200baab 100644
> --- a/arch/x86/lib/relocate.c
> +++ b/arch/x86/lib/relocate.c
> @@ -34,13 +34,10 @@
>  #include <common.h>
>  #include <malloc.h>
>  #include <asm/u-boot-x86.h>
> +#include <asm/relocate.h>
>  #include <elf.h>
>
> -static int copy_uboot_to_ram(void);
> -static int clear_bss(void);
> -static int do_elf_reloc_fixups(void);
> -
> -static int copy_uboot_to_ram(void)
> +int copy_uboot_to_ram(void)
>  {
>        size_t len = (size_t)&__data_end - (size_t)&__text_start;
>
> @@ -49,7 +46,7 @@ static int copy_uboot_to_ram(void)
>        return 0;
>  }
>
> -static int clear_bss(void)
> +int clear_bss(void)
>  {
>        ulong dst_addr = (ulong)&__bss_start + gd->reloc_off;
>        size_t len = (size_t)&__bss_end - (size_t)&__bss_start;
> @@ -59,7 +56,7 @@ static int clear_bss(void)
>        return 0;
>  }
>
> -static int do_elf_reloc_fixups(void)
> +int do_elf_reloc_fixups(void)
>  {
>        Elf32_Rel *re_src = (Elf32_Rel *)(&__rel_dyn_start);
>        Elf32_Rel *re_end = (Elf32_Rel *)(&__rel_dyn_end);
> @@ -92,24 +89,3 @@ static int do_elf_reloc_fixups(void)
>
>        return 0;
>  }
> -
> -void relocate_code(ulong dummy_1, gd_t *id, ulong dummy_2)
> -{
> -       /*
> -        * Copy U-Boot into RAM, clear the BSS and perform relocation
> -        * adjustments
> -        */
> -       copy_uboot_to_ram();
> -       clear_bss();
> -       do_elf_reloc_fixups();
> -
> -       /*
> -        * Transfer execution from Flash to RAM by calculating the address
> -        * of the in-RAM copy of board_init_r() and calling it
> -        */
> -       (board_init_r + gd->reloc_off)(gd, gd->relocaddr);
> -
> -       /* NOTREACHED - board_init_r() does not return */
> -       while (1)
> -               ;
> -}
> --
> 1.7.5.2.317.g391b14
>
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Hi Simon,

On 04/01/12 16:52, Simon Glass wrote:
> Hi Graeme,
> 
> On Sun, Jan 1, 2012 at 8:09 PM, Graeme Russ <graeme.russ@gmail.com> wrote:
>>
>> Signed-off-by: Graeme Russ <graeme.russ@gmail.com>
>> ---
>>  arch/x86/include/asm/init_helpers.h |    5 +
>>  arch/x86/include/asm/relocate.h     |   33 ++++++
>>  arch/x86/lib/board.c                |  188 +++++++++++++++++------------------
>>  arch/x86/lib/init_helpers.c         |   75 ++++++++++++++
>>  arch/x86/lib/relocate.c             |   32 +-----
>>  5 files changed, 206 insertions(+), 127 deletions(-)
> 
> Seems like a fairly major tweak :-) Should this commit be split,
> and/or perhaps explain the purpose in the commit message?

OK, 'tweak' was the wrong word. What this patch does is convert
init_sequence_f_r into an standard init processing loop and cleans up a few
comments along the way (I suppose they could be moved into one last
'documentation' patch)

I've renamed the patch

Regards,

Graeme