drivers/firmware: const-ify DMI API and internals

Three main sets of changes:

1) dmi_get_system_info() return value should have been marked const,
   since callers should not be changing that data.

2) const-ify DMI internals, since DMI firmware tables should,
   whenever possible, be marked const to ensure we never ever write to
   that data area.

3) const-ify DMI API, to enable marking tables const where possible
   in low-level drivers.

And if we're really lucky, this might enable some additional
optimizations on the part of the compiler.

The bulk of the changes are #2 and #3, which are interrelated.  #1 could
have been a separate patch, but it was so small compared to the others,
it was easier to roll it into this changeset.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index dd441ff4af56..7901d5f218ec 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -1965,10 +1965,10 @@ struct dmi_ipmi_data
         u8              slave_addr;
 };
 
-static int __devinit decode_dmi(struct dmi_header *dm,
+static int __devinit decode_dmi(const struct dmi_header *dm,
                                 struct dmi_ipmi_data *dmi)
 {
-        u8              *data = (u8 *)dm;
+        const u8        *data = (const u8 *)dm;
         unsigned long   base_addr;
         u8              reg_spacing;
         u8              len = dm->length;
@@ -2091,13 +2091,14 @@ static __devinit void try_init_dmi(struct dmi_ipmi_data *ipmi_data)
 
 static void __devinit dmi_find_bmc(void)
 {
-        struct dmi_device    *dev = NULL;
+        const struct dmi_device *dev = NULL;
         struct dmi_ipmi_data data;
         int                  rv;
 
         while ((dev = dmi_find_device(DMI_DEV_TYPE_IPMI, NULL, dev))) {
                 memset(&data, 0, sizeof(data));
-                rv = decode_dmi((struct dmi_header *) dev->device_data, &data);
+                rv = decode_dmi((const struct dmi_header *) dev->device_data,
+                                &data);
                 if (!rv)
                         try_init_dmi(&data);
         }