[U-Boot] [PATCH v5 3/8] x86: slimbootloader: Add memory configuration

[Andy Shevchenko]

On Wed, Jul 17, 2019 at 7:41 AM Park, Aiden <aiden.park at intel.com> wrote:
>
> Slim Bootloader provides memory map info thru its HOB list pointer.
> Configure memory size and relocation memory from the HOB data, and
> provide e820 entries as well.
> - Get memory size from the memory map info hob
> - Set ram top for U-Boot relocation lower than 4GB
> - Provide e820 entries from the memory map info hob

> +++ b/arch/x86/cpu/slimbootloader/dram.c

sdram.c is more common name in the sources AFAICS.

> +ulong board_get_usable_ram_top(ulong total_size)
> +{
> +       struct memory_map_info *data = NULL;
> +       int i = 0;
> +       phys_addr_t addr_start = 0;
> +       phys_addr_t addr_end = 0;

Unnecessary assignments (check entire series for them).

> +       data = (struct memory_map_info *)get_memory_map_info();

Casting from / to void * is redundant. Check entire series.

> +       if (!data)
> +               panic("memory map info hob not found\n");

> +       /**
> +        * sorted memory map entries from Slim Bootloader based on physical
> +        * start memory address, from low to high. So do reversed search to
> +        * get highest usable, suitable size, 4KB aligned available memory
> +        * under 4GB.
> +        */

> +       for (i = data->count - 1; i >= 0; i--) {

Hmm... Maybe

i = data->count;
while (i--) {
 ...
}

Easier to read.

> +               if (data->entry[i].type != E820_RAM)
> +                       continue;
> +
> +               addr_start = data->entry[i].addr;
> +               addr_end = addr_start + data->entry[i].size;
> +
> +               if (addr_start > SZ_4G)
> +                       continue;
> +
> +               if (addr_end > SZ_4G)
> +                       addr_end = SZ_4G;
> +
> +               if (addr_end < total_size)
> +                       continue;
> +

> +               /* to relocate u-boot at 4K aligned memory */

u-boot -> U-Boot

> +               addr_end = rounddown(addr_end - total_size, SZ_4K);
> +               if (addr_end >= addr_start) {
> +                       ram_top = (ulong)addr_end + total_size;
> +                       break;
> +               }
> +       }
> +
> +       if (!ram_top)
> +               panic("failed to find available memory for relocation!");
> +
> +       return ram_top;
> +}
> +
> +/**
> + * The memory initialization has already been done in previous Slim Bootloader
> + * stage thru FSP-M. Instead, this sets the ram_size from the memory map info
> + * hob.
> + */
> +int dram_init(void)
> +{
> +       struct memory_map_info *data = NULL;
> +       int i = 0;
> +       phys_size_t ram_size = 0;
> +
> +       data = (struct memory_map_info *)get_memory_map_info();
> +       if (!data)
> +               panic("memory map info hob not found\n");
> +
> +       /**
> +        * sorted memory map entries from Slim Bootloader based on physical
> +        * start memory address, from low to high. So do reversed search to
> +        * simply get highest usable memory address as ram size
> +        */

> +       for (i = data->count - 1; i >= 0; i--) {
> +               if (data->entry[i].type != E820_RAM)
> +                       continue;

Second time?

Perhaps you may do rather macro:

#define for_each_map_info_entry_reversed(...) \
  for () \
  if (!cond) {} else

> +
> +               /* simply use the highest usable memory address as ram size */

ram -> RAM

> +               ram_size = data->entry[i].addr + data->entry[i].size;
> +               break;
> +       }
> +
> +       if (!ram_size)
> +               panic("failed to detect memory size");
> +
> +       gd->ram_size = ram_size;
> +       return 0;
> +}

> +int dram_init_banksize(void)
> +{
> +       /* simply use a single bank to have whole size for now */
> +       if (CONFIG_NR_DRAM_BANKS) {

if (!foo) might be slightly better if ever this code gets modified.

> +               gd->bd->bi_dram[0].start = 0;
> +               gd->bd->bi_dram[0].size = gd->ram_size;
> +       }
> +       return 0;
> +}

> +#define LOADER_MEMORY_MAP_INFO_GUID \
> +       { \
> +       0xa1ff7424, 0x7a1a, 0x478e, \
> +       { 0xa9, 0xe4, 0x92, 0xf3, 0x57, 0xd1, 0x28, 0x32 } \
> +       }

EFI_GUID() ?

> +/**
> + * A single entry of memory map information
> + *
> + * @addr: start address of a memory map entry
> + * @size: size of a memory map entry
> + * @type: usable:1, reserved:2, acpi:3, nvs:4, unusable:5
> + * @flag: only used in Slim Bootloader
> + * @rsvd: padding for alignment
> + */
> +struct memory_map_entry {

> +       phys_addr_t     addr;
> +       phys_size_t     size;

This is comes from hardware, isn't it? Probably better to use fixed width typo

> +       u8      type;
> +       u8      flag;
> +       u8      rsvd[6];
> +} __packed;

-- 
With Best Regards,
Andy Shevchenko