1 // Support for enabling/disabling BIOS ram shadowing.
3 // Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
4 // Copyright (C) 2006 Fabrice Bellard
6 // This file may be distributed under the terms of the GNU GPLv3 license.
8 #include "util.h" // memcpy
9 #include "pci.h" // pci_config_writeb
11 #define BIOS_TMP_STORAGE 0x30000 /* 64 KB used to copy the BIOS to shadow RAM */
13 // Test if 'addr' is in the range from 'start'..'start+size'
14 #define IN_RANGE(addr, start, size) ({ \
15 u32 __addr = (addr); \
16 u32 __start = (start); \
17 u32 __size = (size); \
18 (__addr - __start < __size); \
21 // Enable shadowing and copy bios.
23 copy_bios(PCIDevice d)
25 int v = pci_config_readb(d, 0x59);
27 pci_config_writeb(d, 0x59, v);
28 memcpy((void *)0x000f0000, (void *)BIOS_TMP_STORAGE, 0x10000);
31 // Make the BIOS code segment area (0xf0000) writable.
38 dprintf(3, "enabling shadow ram\n");
40 // Locate chip controlling ram shadowing.
42 int ret = pci_find_device(0x8086, 0x1237, 0, &d);
44 dprintf(1, "Unable to unlock ram - bridge not found\n");
48 // Copy the bios to a temporary area.
49 memcpy((void *)BIOS_TMP_STORAGE, (void *)0x000f0000, 0x10000);
51 // Enable shadowing and copy bios.
52 if (IN_RANGE((u32)copy_bios, 0xf0000, 0x10000)) {
53 // Jump to shadow enable function - use the copy in the
54 // temporary storage area so that memory does not change under
55 // the executing code.
56 u32 pos = (u32)copy_bios - 0xf0000 + BIOS_TMP_STORAGE;
57 void (*func)(PCIDevice) = (void*)pos;
63 // Clear the temporary area.
64 memset((void *)BIOS_TMP_STORAGE, 0, 0x10000);
67 // Make the BIOS code segment area (0xf0000) read-only.
74 dprintf(3, "locking shadow ram\n");
77 int ret = pci_find_device(0x8086, 0x1237, 0, &d);
79 dprintf(1, "Unable to lock ram - bridge not found\n");
84 int v = pci_config_readb(d, 0x59);
85 v = (v & 0x0f) | (0x10);
86 pci_config_writeb(d, 0x59, v);