-mem_alignment = 1024 * 1024 * 1024 # 1 GBytes
-table_alignment = 128 * 1024
-
-mem_size = get_mem_size()
-
-# start at memory address aligned at 128K.
-offset = align_up(mem_size, table_alignment)
-
-dprint('mem_size %x offset %x' %(mem_size, offset))
-mf = open("/dev/mem")
-mf_fileno = mf.fileno()
-
-while offset % mem_alignment: # do not cross the 1G boundary while searching
- (step, magic, mid, base, size) = parse_mem_at(offset, CBMEM_ENTRY_FORMAT)
- if magic == CBMEM_MAGIC:
- offset = offset + step
- break
- offset += table_alignment
-else:
- print 'Did not find the CBMEM'
- sys.exit(0)
-
-for i in (range(1, CBMEM_MAX_ENTRIES)):
- (_, magic, mid, base, size) = parse_mem_at(offset, CBMEM_ENTRY_FORMAT)
- if mid == 0:
- break
-
- print '%x, %x, %x' % (mid, base, size)
- if mid == 0x54494d45:
- process_timers(base)
- if mid == 0x434f4e53:
- process_console(base)
-
- offset = offset + step
-
-mf.close()
+def ipchksum(buf):
+ '''Checksumming function used on the coreboot tables. The buffer being
+ checksummed is summed up as if it was an array of 16 bit unsigned
+ integers. If there are an odd number of bytes, the last element is zero
+ extended.'''
+
+ size = len(buf)
+ odd = size % 2
+ fmt = "<%dH" % ((size - odd) / 2)
+ if odd:
+ fmt += "B"
+ shorts = struct.unpack(fmt, buf)
+ checksum = sum(shorts)
+ checksum = (checksum >> 16) + (checksum & 0xffff)
+ checksum += (checksum >> 16)
+ checksum = ~checksum & 0xffff
+ return checksum
+
+def parse_tables(base, length):
+ '''Find the coreboot tables in memory and process whatever we can.'''
+
+ class CBTableHeader(CStruct):
+ struct_members = (
+ ("4s", "signature"),
+ ("I", "header_bytes"),
+ ("I", "header_checksum"),
+ ("I", "table_bytes"),
+ ("I", "table_checksum"),
+ ("I", "table_entries")
+ )
+
+ class CBTableEntry(CStruct):
+ struct_members = (
+ ("I", "tag"),
+ ("I", "size")
+ )
+
+ class CBTableForward(CBTableEntry):
+ struct_members = CBTableEntry.struct_members + (
+ ("Q", "forward"),
+ )
+
+ class CBMemTab(CBTableEntry):
+ struct_members = CBTableEntry.struct_members + (
+ ("L", "cbmem_tab"),
+ )
+
+ for addr in range(base, base + length, 16):
+ header = CBTableHeader(addr)
+ if header.signature == "LBIO":
+ break
+ else:
+ return -1
+
+ if header.header_bytes == 0:
+ return -1
+
+ if ipchksum(header.raw_memory) != 0:
+ print "Bad header checksum"
+ return -1
+
+ addr += header.header_bytes
+ table = get_phys_mem(addr, header.table_bytes)
+ if ipchksum(table) != header.table_checksum:
+ print "Bad table checksum"
+ return -1
+
+ for i in range(header.table_entries):
+ entry = CBTableEntry(addr)
+ if entry.tag == 0x11: # Forwarding entry
+ return parse_tables(CBTableForward(addr).forward, length)
+ elif entry.tag == 0x16: # Timestamps
+ process_timers(CBMemTab(addr).cbmem_tab)
+ elif entry.tag == 0x17: # CBMEM console
+ process_console(CBMemTab(addr).cbmem_tab)
+
+ addr += entry.size
+
+ return 0
+
+def main():
+ for base, length in (0x00000000, 0x1000), (0x000f0000, 0x1000):
+ if parse_tables(base, length):
+ break
+ else:
+ print "Didn't find the coreboot tables"
+ return 0
+
+if __name__ == "__main__":
+ sys.exit(main())