CFI: increase performance of function find_sector()

Tested on TQM5200S-BD with Samsung K8P2815UQB

Signed-off-by: Jens Gehrlein <sew_s@tqs.de>
Signed-off-by: Stefan Roese <sr@denx.de>

diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index 1bd0e2b..bc5e151 100644 (file)
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -774,17 +774,26 @@ static void flash_add_byte (flash_info_t * info, cfiword_t * cword, uchar c)
        }
 }
 
-/* loop through the sectors from the highest address when the passed
- * address is greater or equal to the sector address we have a match
+/*
+ * Loop through the sector table starting from the previously found sector.
+ * Searches forwards or backwards, dependent on the passed address.
  */
 static flash_sect_t find_sector (flash_info_t * info, ulong addr)
 {
-       flash_sect_t sector;
+       static flash_sect_t saved_sector = 0; /* previously found sector */
+       flash_sect_t sector = saved_sector;
 
-       for (sector = info->sector_count - 1; sector >= 0; sector--) {
-               if (addr >= info->start[sector])
-                       break;
-       }
+       while ((info->start[sector] < addr)
+                       && (sector < info->sector_count - 1))
+               sector++;
+       while ((info->start[sector] > addr) && (sector > 0))
+               /*
+                * also decrements the sector in case of an overshot
+                * in the first loop
+                */
+               sector--;
+
+       saved_sector = sector;
        return sector;
 }