memmap.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <cbmem.h>
#include <cpu/x86/smm.h>
#include <soc/iosf.h>
 
static size_t smm_region_size(void)
{
        u32 smm_size;
        smm_size =  iosf_bunit_read(BUNIT_SMRRH) & 0xFFFF;
        smm_size -= iosf_bunit_read(BUNIT_SMRRL) & 0xFFFF;
        smm_size = (smm_size + 1) << 20;
        return smm_size;
}
 
void smm_region(uintptr_t *start, size_t *size)
{
        *start = (iosf_bunit_read(BUNIT_SMRRL) & 0xFFFF) << 20;
        *size = smm_region_size();
}
 
void *cbmem_top_chipset(void)
{
        uintptr_t smm_base;
        size_t smm_size;
 
        /*
         *     +-------------------------+  Top of RAM (aligned)
         *     | System Management Mode  |
         *     |      code and data      |  Length: CONFIG_SMM_TSEG_SIZE
         *     |         (TSEG)          |
         *     +-------------------------+  SMM base (aligned)
         *     |                         |
         *     | Chipset Reserved Memory |  Length: Multiple of CONFIG_SMM_TSEG_SIZE
         *     |                         |
         *     +-------------------------+  top_of_ram (aligned)
         *     |                         |
         *     |       CBMEM Root        |
         *     |                         |
         *     +-------------------------+
         *     |                         |
         *     |   FSP Reserved Memory   |
         *     |                         |
         *     +-------------------------+
         *     |                         |
         *     |  Various CBMEM Entries  |
         *     |                         |
         *     +-------------------------+  top_of_stack (8 byte aligned)
         *     |                         |
         *     |   stack (CBMEM Entry)   |
         *     |                         |
         *     +-------------------------+
        */
 
        smm_region(&smm_base, &smm_size);
        return (void *)smm_base;
}