From 21096c0af3733b63c1e9ee7772d95a0551b4fc85 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Fri, 27 Nov 2020 14:40:48 +0200 Subject: [PATCH] x86: tangier: Find proper memory region for relocation It appears that U-Boot works by luck on Intel Edison board because the amount of RAM is less than 1 GB and standard way of calculating the top of it work for this configuration. However, this won't work if the amount of RAM is different and split differently in address space. We have to find the suitable window correctly. Find proper memory region for relocation by scanning MMAP SFI table in board_get_usable_ram_top() callback. According to the address map documentation the Main Memory is guaranteed to lie in the 0..2 GB range, that's why we limit search by this range. Fixes: e71de54a4943 ("x86: Add Intel Tangier support") Signed-off-by: Andy Shevchenko Reviewed-by: Simon Glass Reviewed-by: Bin Meng [bmeng: fixed a typo in the commit message] Signed-off-by: Bin Meng --- arch/x86/cpu/tangier/sdram.c | 43 ++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/arch/x86/cpu/tangier/sdram.c b/arch/x86/cpu/tangier/sdram.c index df3b9e4ec9..afb08476ed 100644 --- a/arch/x86/cpu/tangier/sdram.c +++ b/arch/x86/cpu/tangier/sdram.c @@ -196,6 +196,49 @@ unsigned int install_e820_map(unsigned int max_entries, return sfi_setup_e820(max_entries, entries); } +/* + * This function looks for the highest region of memory lower than 2GB which + * has enough space for U-Boot where U-Boot is aligned on a page boundary. It + * overrides the default implementation found elsewhere which simply picks the + * end of RAM, wherever that may be. The location of the stack, the relocation + * address, and how far U-Boot is moved by relocation are set in the global + * data structure. + */ +ulong board_get_usable_ram_top(ulong total_size) +{ + struct sfi_table_simple *sb; + struct sfi_mem_entry *mentry; + ulong dest_addr = 0; + u32 i; + + sb = sfi_search_mmap(); + if (!sb) + panic("No available memory found for relocation"); + + sfi_for_each_mentry(i, sb, mentry) { + unsigned long long start, end; + + if (mentry->type != SFI_MEM_CONV) + continue; + + start = mentry->phys_start; + end = start + (mentry->pages << 12); + + /* Filter memory over 2GB. */ + if (end > 0x7fffffffULL) + end = 0x80000000ULL; + /* Skip this region if it's too small. */ + if (end - start < total_size) + continue; + + /* Use this address if it's the largest so far. */ + if (end > dest_addr) + dest_addr = end; + } + + return dest_addr; +} + int dram_init_banksize(void) { sfi_get_bank_size(); -- 2.39.5