gpmr.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <console/console.h>
#include <intelblocks/gpmr.h>
#include <intelblocks/pcr.h>
#include <soc/pcr_ids.h>
 
/* GPMR Register read given offset */
uint32_t gpmr_read32(uint16_t offset)
{
        return pcr_read32(PID_DMI, offset);
}
 
/* GPMR Register write given offset and val */
void gpmr_write32(uint16_t offset, uint32_t val)
{
        return pcr_write32(PID_DMI, offset, val);
}
 
void gpmr_or32(uint16_t offset, uint32_t ordata)
{
        return pcr_or32(PID_DMI, offset, ordata);
}
 
/* Check for available free gpmr */
static int get_available_gpmr(void)
{
        int i;
        uint32_t val;
 
        for (i = 0; i < MAX_GPMR_REGS; i++) {
                val = gpmr_read32(GPMR_DID_OFFSET(i));
                if (!(val & GPMR_EN))
                        return i;
        }
        printk(BIOS_ERR, "%s: No available free gpmr found\n", __func__);
        return CB_ERR;
}
 
/* Configure GPMR for the given base and size of extended BIOS Region */
enum cb_err enable_gpmr(uint32_t base, uint32_t size, uint32_t dest_id)
{
        int gpmr_num;
        uint32_t limit;
 
        if (base & ~(GPMR_BASE_MASK << GPMR_BASE_SHIFT)) {
                printk(BIOS_ERR, "base is not 64-KiB aligned!\n");
                return CB_ERR;
        }
 
        limit = base + (size - 1);
 
        if (limit < base) {
                printk(BIOS_ERR, "Invalid limit: limit cannot be less than base!\n");
                return CB_ERR;
        }
 
        if ((limit & ~GPMR_LIMIT_MASK) != 0xffff) {
                printk(BIOS_ERR, "limit does not end on a 64-KiB boundary!\n");
                return CB_ERR;
        }
 
        /* Get available free GPMR */
        gpmr_num = get_available_gpmr();
        if (gpmr_num == CB_ERR)
                return CB_ERR;
 
        /* Program Range for the given decode window */
        gpmr_write32(GPMR_OFFSET(gpmr_num), (limit & GPMR_LIMIT_MASK) |
                ((base >> GPMR_BASE_SHIFT) & GPMR_BASE_MASK));
 
        /* Program source decode enable bit and the Destination ID */
        gpmr_write32(GPMR_DID_OFFSET(gpmr_num), dest_id | GPMR_EN);
 
        return CB_SUCCESS;
}