mtd-physmap: add support users can assign the probe type in board files

There are three reasons to add this support:
1. users probably know the interface type of their flashs, then probe
can be faster if they give the right type in platform data since wrong
types will not be detected.
2. sometimes, detecting can cause destory to system. For example, for
kernel XIP, detecting can cause NOR enter a mode instructions can not
be fetched right, which will make kernel crash.
3. For a new probe which is not listed in the rom_probe_types, if users
assign it in board files, physmap can still probe it.

Signed-off-by: Barry Song <21cnbao@gmail.com>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

2 files changed, 7 insertions, 2 deletions

diff --git a/drivers/mtd/maps/physmap.c b/drivers/mtd/maps/physmap.c
index 829aa4bee54f..4c18b98a3110 100644
--- a/drivers/mtd/maps/physmap.c
+++ b/drivers/mtd/maps/physmap.c
@@ -136,8 +136,12 @@ static int physmap_flash_probe(struct platform_device *dev)
                 simple_map_init(&info->map[i]);
 
                 probe_type = rom_probe_types;
-                for (; info->mtd[i] == NULL && *probe_type != NULL; probe_type++)
-                        info->mtd[i] = do_map_probe(*probe_type, &info->map[i]);
+                if (physmap_data->probe_type == NULL) {
+                        for (; info->mtd[i] == NULL && *probe_type != NULL; probe_type++)
+                                info->mtd[i] = do_map_probe(*probe_type, &info->map[i]);
+                } else
+                        info->mtd[i] = do_map_probe(physmap_data->probe_type, &info->map[i]);
+
                 if (info->mtd[i] == NULL) {
                         dev_err(&dev->dev, "map_probe failed\n");
                         err = -ENXIO;
diff --git a/include/linux/mtd/physmap.h b/include/linux/mtd/physmap.h
index 76f7cabf07d3..bcfd9f777454 100644
--- a/include/linux/mtd/physmap.h
+++ b/include/linux/mtd/physmap.h
@@ -25,6 +25,7 @@ struct physmap_flash_data {
         void                    (*set_vpp)(struct map_info *, int);
         unsigned int            nr_parts;
         unsigned int            pfow_base;
+        char                    *probe_type;
         struct mtd_partition    *parts;
 };