add get_option to libpayload, so coreboot cmos options can be queried.

[coreboot.git] / payloads / libpayload / drivers / options.c

diff --git a/payloads/libpayload/drivers/options.c b/payloads/libpayload/drivers/options.c
new file mode 100644 (file)
index 0000000..aa43340
--- /dev/null
+++ b/payloads/libpayload/drivers/options.c
@@ -0,0 +1,106 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 coresystems GmbH
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <libpayload.h>
+#include <coreboot_tables.h>
+
+static int options_checksum_valid(void)
+{
+       int i;
+       int range_start = lib_sysinfo.cmos_range_start;
+       int range_end = lib_sysinfo.cmos_range_end;
+       int checksum_location = lib_sysinfo.cmos_checksum_location;
+       u16 checksum = 0, checksum_old;
+
+       for(i = range_start; i <= range_end; i++) {
+               checksum += nvram_read(i);
+       }
+       checksum = (~checksum)&0xffff;
+
+       checksum_old = ((nvram_read(checksum_location)<<8) | nvram_read(checksum_location+1));
+
+       return (checksum_old == checksum);
+}
+
+static int get_cmos_value(u32 bitnum, u32 len, void *valptr)
+{
+       u8 *value = (u8 *)valptr;
+       int offs = 0;
+       u32 addr, bit;
+       u8 reg8;
+
+       value = valptr;
+
+       /* Convert to byte borders */
+       addr=(bitnum / 8);
+       bit=(bitnum % 8);
+
+       /* Handle single byte or less */
+       if(len <= 8) {
+               reg8 = nvram_read(addr);
+               reg8 >>= bit;
+               value[0] = reg8 & ((1 << len) -1);
+               return 0;
+       }
+
+       /* When handling more than a byte, copy whole bytes */
+       while (len > 0) {
+               len -= 8;
+               value[offs++]=nvram_read(addr++);
+       }
+
+       return 0;
+}
+
+int get_option(void *dest, char *name)
+{
+       struct cb_cmos_option_table *option_table = lib_sysinfo.option_table;
+       struct cb_cmos_entries *cmos_entry;
+       int len = strnlen(name, CMOS_MAX_NAME_LENGTH);
+       
+       /* cmos entries are located right after the option table */
+       cmos_entry=(struct cb_cmos_entries*)((unsigned char *)option_table + option_table->header_length);
+
+       for (   cmos_entry = (struct cb_cmos_entries*)((unsigned char *)option_table + option_table->header_length);
+               cmos_entry->tag == CB_TAG_OPTION;
+               cmos_entry = (struct cb_cmos_entries*)((unsigned char *)cmos_entry + cmos_entry->size)) {
+               if (memcmp(cmos_entry->name, name, len))
+                       continue;
+               if(get_cmos_value(cmos_entry->bit, cmos_entry->length, dest))
+                       return 1;
+
+               if(!options_checksum_valid())
+                       return 1;
+
+               return 0;
+       }
+
+       printf("ERROR: No such CMOS option (%s)\n", name);
+       return 1;
+}