Hi Simon,
On Mon, Aug 3, 2015 at 8:10 AM, Simon Glass sjg@chromium.org wrote:
At present we have a simple assignment to gd. With some archs this is implemented as a register or through some other means; a simple assignment does not suit in all cases.
Change this to a function and add documentation to describe how this all works.
Signed-off-by: Simon Glass sjg@chromium.org
common/board_f.c | 14 +++++++++++--- include/common.h | 40 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 51 insertions(+), 3 deletions(-)
diff --git a/common/board_f.c b/common/board_f.c index a947770..3d1f305 100644 --- a/common/board_f.c +++ b/common/board_f.c @@ -1024,15 +1024,23 @@ void board_init_f_r(void) #endif /* CONFIG_X86 */
#ifndef CONFIG_X86 -ulong board_init_f_mem(ulong top) +__weak void arch_setup_gdt(struct global_data *gd_ptr) {
gd = gd_ptr;+}
+ulong board_init_f_mem(ulong top, ulong reserve_size)
What is reserve_size? I don't see it is used by this function. If we change the signature, we need also update arc and ppc4xx start.S otherwise they will break.
+{
struct global_data *gd_ptr;/* Leave space for the stack we are running with now */ top -= 0x40; top -= sizeof(struct global_data); top = ALIGN(top, 16);
gd = (struct global_data *)top;memset((void *)gd, '\0', sizeof(*gd));
gd_ptr = (struct global_data *)top;memset(gd_ptr, '\0', sizeof(*gd));arch_setup_gdt(gd_ptr);
gdt? Should be just arch_setup_gd()?
#ifdef CONFIG_SYS_MALLOC_F_LEN top -= CONFIG_SYS_MALLOC_F_LEN; diff --git a/include/common.h b/include/common.h index fcc9ae7..029eb1f 100644 --- a/include/common.h +++ b/include/common.h @@ -217,6 +217,46 @@ extern char console_buffer[]; /* arch/$(ARCH)/lib/board.c */ void board_init_f(ulong); void board_init_r(gd_t *, ulong) __attribute__ ((noreturn));
+/**
- board_init_f_mem() - Allocate global data and set stack position
- This function is called by each architecture very early in the start-up
- code to set up the environment for board_init_f(). It allocates space for
- global_data (see include/asm-generic/global_data.h) and places the stack
- below this.
- This function requires a stack[1] Normally this is at @top. The function
- starts allocating space from 64 bytes below @top. First it creates space
- for global_data. then it calls arch_setup_gd() which sets gd to point to
Nits: . -> ,
- the global_data space and can reserve additional bytes of space if
- required). Finally it allocates early malloc() memory
- (CONFIG_SYS_MALLOC_F_LEN). The new top of the stack is just below this,
- and it returned by this function.
- [1] Strictly speaking it would be possible to implement this function
- in C on many archs such that it does not require a stack. However this
- does not seem hugely important as only 64 byte are wasted.
Where is the 64 bytes it uses? I only see a variable gd_ptr on the stack.
- @top: Top of available memory, also normally the top of the stack
- @return: New stack location
- */
+ulong board_init_f_mem(ulong top, ulong reserve_size);
I don't like the name board_init_f_mem(). It actually does two things: creates global data pointer and reserve the early malloc() memory size. Also it looks like it's more like an arch thing instead of a board's. How about setup_gd_f_mem()?
+/**
- arch_setup_gdt() - Set up the global_data pointer
- This pointer is special in some architectures and cannot easily be assigned
- to. For example on x86 it is implemented by adding a specific record to its
- Global Descriptor Table! So we we provide a function to carry out this task.
- For most architectures this can simply be:
- gd = gd_ptr;
- @gd_ptr: Pointer to global data
- */
+void arch_setup_gdt(gd_t *gd_ptr);
int checkboard(void); int show_board_info(void); int checkflash(void); --
Regards, Bin