[MTD] OneNAND: add subpage write support

OneNAND supports up to 4 writes at one NAND page. Add support of this feature.

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

diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index 3fab4d1..51fb840 100644 (file)
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -192,8 +192,6 @@ static int onenand_command(struct mtd_info *mtd, int cmd, loff_t addr, size_t le
        struct onenand_chip *this = mtd->priv;
        int value, readcmd = 0, block_cmd = 0;
        int block, page;
-       /* Now we use page size operation */
-       int sectors = 4, count = 4;
 
        /* Address translation */
        switch (cmd) {
@@ -245,6 +243,8 @@ static int onenand_command(struct mtd_info *mtd, int cmd, loff_t addr, size_t le
        }
 
        if (page != -1) {
+               /* Now we use page size operation */
+               int sectors = 4, count = 4;
                int dataram;
 
                switch (cmd) {
@@ -914,6 +914,10 @@ static int onenand_verify_page(struct mtd_info *mtd, u_char *buf, loff_t addr)
        void __iomem *dataram0, *dataram1;
        int ret = 0;
 
+       /* In partial page write, just skip it */
+       if ((addr & (mtd->writesize - 1)) != 0)
+               return 0;
+
        this->command(mtd, ONENAND_CMD_READ, addr, mtd->writesize);
 
        ret = this->wait(mtd, FL_READING);
@@ -936,7 +940,7 @@ static int onenand_verify_page(struct mtd_info *mtd, u_char *buf, loff_t addr)
 #define onenand_verify_oob(...)                (0)
 #endif
 
-#define NOTALIGNED(x)  ((x & (mtd->writesize - 1)) != 0)
+#define NOTALIGNED(x)  ((x & (this->subpagesize - 1)) != 0)
 
 /**
  * onenand_write - [MTD Interface] write buffer to FLASH
@@ -954,6 +958,7 @@ static int onenand_write(struct mtd_info *mtd, loff_t to, size_t len,
        struct onenand_chip *this = mtd->priv;
        int written = 0;
        int ret = 0;
+       int column, subpage;
 
        DEBUG(MTD_DEBUG_LEVEL3, "onenand_write: to = 0x%08x, len = %i\n", (unsigned int) to, (int) len);
 
@@ -972,45 +977,61 @@ static int onenand_write(struct mtd_info *mtd, loff_t to, size_t len,
                 return -EINVAL;
         }
 
+       column = to & (mtd->writesize - 1);
+       subpage = column || (len & (mtd->writesize - 1));
+
        /* Grab the lock and see if the device is available */
        onenand_get_device(mtd, FL_WRITING);
 
        /* Loop until all data write */
        while (written < len) {
-               int thislen = min_t(int, mtd->writesize, len - written);
-
-               this->command(mtd, ONENAND_CMD_BUFFERRAM, to, mtd->writesize);
+               int bytes = mtd->writesize;
+               int thislen = min_t(int, bytes, len - written);
+               u_char *wbuf = (u_char *) buf;
+
+               this->command(mtd, ONENAND_CMD_BUFFERRAM, to, bytes);
+
+               /* Partial page write */
+               if (subpage) {
+                       bytes = min_t(int, bytes - column, (int) len);
+                       memset(this->page_buf, 0xff, mtd->writesize);
+                       memcpy(this->page_buf + column, buf, bytes);
+                       wbuf = this->page_buf;
+                       /* Even though partial write, we need page size */
+                       thislen = mtd->writesize;
+               }
 
-               this->write_bufferram(mtd, ONENAND_DATARAM, buf, 0, thislen);
+               this->write_bufferram(mtd, ONENAND_DATARAM, wbuf, 0, thislen);
                this->write_bufferram(mtd, ONENAND_SPARERAM, ffchars, 0, mtd->oobsize);
 
                this->command(mtd, ONENAND_CMD_PROG, to, mtd->writesize);
 
-               onenand_update_bufferram(mtd, to, 1);
+               /* In partial page write we don't update bufferram */
+               onenand_update_bufferram(mtd, to, !subpage);
 
                ret = this->wait(mtd, FL_WRITING);
                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_write: write filaed %d\n", ret);
-                       goto out;
+                       break;
                }
 
-               written += thislen;
-
                /* Only check verify write turn on */
-               ret = onenand_verify_page(mtd, (u_char *) buf, to);
+               ret = onenand_verify_page(mtd, (u_char *) wbuf, to);
                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_write: verify failed %d\n", ret);
-                       goto out;
+                       break;
                }
 
+               written += thislen;
+
                if (written == len)
                        break;
 
+               column = 0;
                to += thislen;
                buf += thislen;
        }
 
-out:
        /* Deselect and wake up anyone waiting on the device */
        onenand_release_device(mtd);
 
@@ -2021,23 +2042,30 @@ int onenand_scan(struct mtd_info *mtd, int maxchips)
        init_waitqueue_head(&this->wq);
        spin_lock_init(&this->chip_lock);
 
+       /*
+        * Allow subpage writes up to oobsize.
+        */
        switch (mtd->oobsize) {
        case 64:
                this->ecclayout = &onenand_oob_64;
+               mtd->subpage_sft = 2;
                break;
 
        case 32:
                this->ecclayout = &onenand_oob_32;
+               mtd->subpage_sft = 1;
                break;
 
        default:
                printk(KERN_WARNING "No OOB scheme defined for oobsize %d\n",
                        mtd->oobsize);
+               mtd->subpage_sft = 0;
                /* To prevent kernel oops */
                this->ecclayout = &onenand_oob_32;
                break;
        }
 
+       this->subpagesize = mtd->writesize >> mtd->subpage_sft;
        mtd->ecclayout = this->ecclayout;
 
        /* Fill in remaining MTD driver data */

diff --git a/include/linux/mtd/onenand.h b/include/linux/mtd/onenand.h
index 62ca0f4..fe3500d 100644 (file)
--- a/include/linux/mtd/onenand.h
+++ b/include/linux/mtd/onenand.h
@@ -88,6 +88,7 @@ struct onenand_bufferram {
  *                     operation is in progress
  * @state:             [INTERN] the current state of the OneNAND device
  * @page_buf:          data buffer
+ * @subpagesize:       [INTERN] holds the subpagesize
  * @ecclayout:         [REPLACEABLE] the default ecc placement scheme
  * @bbm:               [REPLACEABLE] pointer to Bad Block Management
  * @priv:              [OPTIONAL] pointer to private chip date
@@ -128,6 +129,7 @@ struct onenand_chip {
        onenand_state_t         state;
        unsigned char           *page_buf;
 
+       int                     subpagesize;
        struct nand_ecclayout   *ecclayout;
 
        void                    *bbm;