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/** @file
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include "VirtHstiDxe.h"
#define WRITE_BYTE_CMD 0x10
#define BLOCK_ERASE_CMD 0x20
#define CLEAR_STATUS_CMD 0x50
#define READ_STATUS_CMD 0x70
#define READ_DEVID_CMD 0x90
#define BLOCK_ERASE_CONFIRM_CMD 0xd0
#define READ_ARRAY_CMD 0xff
#define CLEARED_ARRAY_STATUS 0x00
/* based on QemuFlashDetected (QemuFlashFvbServicesRuntimeDxe) */
UINT32
VirtHstiQemuFirmwareFlashCheck (
UINT32 Address
)
{
volatile UINT8 *Ptr;
UINTN Offset;
UINT8 OriginalUint8;
UINT8 ProbeUint8;
for (Offset = 0; Offset < EFI_PAGE_SIZE; Offset++) {
Ptr = (UINT8 *)(UINTN)(Address + Offset);
ProbeUint8 = *Ptr;
if ((ProbeUint8 != CLEAR_STATUS_CMD) &&
(ProbeUint8 != READ_STATUS_CMD) &&
(ProbeUint8 != CLEARED_ARRAY_STATUS))
{
break;
}
}
if (Offset >= EFI_PAGE_SIZE) {
DEBUG ((DEBUG_INFO, "%a: check failed\n", __func__));
return QEMU_FIRMWARE_FLASH_UNKNOWN;
}
OriginalUint8 = *Ptr;
*Ptr = CLEAR_STATUS_CMD;
ProbeUint8 = *Ptr;
if ((OriginalUint8 != CLEAR_STATUS_CMD) &&
(ProbeUint8 == CLEAR_STATUS_CMD))
{
*Ptr = OriginalUint8;
DEBUG ((DEBUG_INFO, "%a: %p behaves as RAM\n", __func__, Ptr));
return QEMU_FIRMWARE_FLASH_IS_RAM;
}
*Ptr = READ_STATUS_CMD;
ProbeUint8 = *Ptr;
if (ProbeUint8 == OriginalUint8) {
DEBUG ((DEBUG_INFO, "%a: %p behaves as ROM\n", __func__, Ptr));
return QEMU_FIRMWARE_FLASH_IS_ROM;
}
if (ProbeUint8 == READ_STATUS_CMD) {
*Ptr = OriginalUint8;
DEBUG ((DEBUG_INFO, "%a: %p behaves as RAM\n", __func__, Ptr));
return QEMU_FIRMWARE_FLASH_IS_RAM;
}
if (ProbeUint8 == CLEARED_ARRAY_STATUS) {
*Ptr = WRITE_BYTE_CMD;
*Ptr = OriginalUint8;
*Ptr = READ_STATUS_CMD;
ProbeUint8 = *Ptr;
*Ptr = READ_ARRAY_CMD;
if (ProbeUint8 & 0x10 /* programming error */) {
DEBUG ((DEBUG_INFO, "%a: %p behaves as FLASH, write-protected\n", __func__, Ptr));
return QEMU_FIRMWARE_FLASH_READ_ONLY;
} else {
DEBUG ((DEBUG_INFO, "%a: %p behaves as FLASH, writable\n", __func__, Ptr));
return QEMU_FIRMWARE_FLASH_WRITABLE;
}
}
DEBUG ((DEBUG_INFO, "%a: check failed\n", __func__));
return QEMU_FIRMWARE_FLASH_UNKNOWN;
}
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