[MTD] OneNAND: Reduce internal BufferRAM operations

It use blockpage instead of a pair (block, page). It can also cover a small chunk access. 0x00, 0x20, 0x40 and so on.

And in JFFS2 behavior, sometimes it reads two pages alternatively.
e.g., It first reads A page, B page and A page.
So we check another bufferram to find requested page.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

2 files changed, 25 insertions, 30 deletions

diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index eb94d94964..9f4fe73bc1 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -577,19 +577,22 @@ static int onenand_write_bufferram(struct mtd_info *mtd, int area,
 static int onenand_check_bufferram(struct mtd_info *mtd, loff_t addr)
 {
         struct onenand_chip *this = mtd->priv;
-        int block, page;
-        int i;
+        int blockpage;
+        unsigned int i;
 
-        block = (int) (addr >> this->erase_shift);
-        page = (int) (addr >> this->page_shift) & this->page_mask;
+        blockpage = (int) (addr >> this->page_shift);
 
+        /* Is there valid data? */
         i = ONENAND_CURRENT_BUFFERRAM(this);
+        if (this->bufferram[i].blockpage == blockpage)
+                return 1;
 
-        /* Is there valid data? */
-        if (this->bufferram[i].block == block &&
-            this->bufferram[i].page == page &&
-            this->bufferram[i].valid)
+        /* Check another BufferRAM */
+        i = ONENAND_NEXT_BUFFERRAM(this);
+        if (this->bufferram[i].blockpage == blockpage) {
+                ONENAND_SET_NEXT_BUFFERRAM(this);
                 return 1;
+        }
 
         return 0;
 }
@@ -602,30 +605,26 @@ static int onenand_check_bufferram(struct mtd_info *mtd, loff_t addr)
  *
  * Update BufferRAM information
  */
-static int onenand_update_bufferram(struct mtd_info *mtd, loff_t addr,
+static void onenand_update_bufferram(struct mtd_info *mtd, loff_t addr,
                 int valid)
 {
         struct onenand_chip *this = mtd->priv;
-        int block, page;
-        int i;
+        int blockpage;
+        unsigned int i;
 
-        block = (int) (addr >> this->erase_shift);
-        page = (int) (addr >> this->page_shift) & this->page_mask;
+        blockpage = (int) (addr >> this->page_shift);
 
-        /* Invalidate BufferRAM */
-        for (i = 0; i < MAX_BUFFERRAM; i++) {
-                if (this->bufferram[i].block == block &&
-                    this->bufferram[i].page == page)
-                        this->bufferram[i].valid = 0;
-        }
+        /* Invalidate another BufferRAM */
+        i = ONENAND_NEXT_BUFFERRAM(this);
+        if (this->bufferram[i].blockpage == blockpage) {
+                this->bufferram[i].blockpage = -1;
 
         /* Update BufferRAM */
         i = ONENAND_CURRENT_BUFFERRAM(this);
-        this->bufferram[i].block = block;
-        this->bufferram[i].page = page;
-        this->bufferram[i].valid = valid;
-
-        return 0;
+        if (valid)
+                this->bufferram[i].blockpage = blockpage;
+        else
+                this->bufferram[i].blockpage = -1;
 }
 
 /**
diff --git a/include/linux/mtd/onenand.h b/include/linux/mtd/onenand.h
index a5e6c4bf7a..d8af8a95e5 100644
--- a/include/linux/mtd/onenand.h
+++ b/include/linux/mtd/onenand.h
@@ -42,14 +42,10 @@ typedef enum {
 
 /**
  * struct onenand_bufferram - OneNAND BufferRAM Data
- * @block:              block address in BufferRAM
- * @page:               page address in BufferRAM
- * @valid:              valid flag
+ * @blockpage:          block & page address in BufferRAM
  */
 struct onenand_bufferram {
-        int block;
-        int page;
-        int valid;
+        int     blockpage;
 };
 
 /**