mtd: bcm47xxsflash: writing support

Tested with BCM4706.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/devices/bcm47xxsflash.c b/drivers/mtd/devices/bcm47xxsflash.c
index 534cb741b107539798863a85d381359e6519f73e..77de29bc02ba03069609d6aeff8afa9691cf8d4c 100644 (file)
--- a/drivers/mtd/devices/bcm47xxsflash.c
+++ b/drivers/mtd/devices/bcm47xxsflash.c
@@ -116,6 +116,127 @@ static int bcm47xxsflash_read(struct mtd_info *mtd, loff_t from, size_t len,
        return len;
 }
 
+static int bcm47xxsflash_write_st(struct mtd_info *mtd, u32 offset, size_t len,
+                                 const u_char *buf)
+{
+       struct bcm47xxsflash *b47s = mtd->priv;
+       int written = 0;
+
+       /* Enable writes */
+       bcm47xxsflash_cmd(b47s, OPCODE_ST_WREN);
+
+       /* Write first byte */
+       b47s->cc_write(b47s, BCMA_CC_FLASHADDR, offset);
+       b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
+
+       /* Program page */
+       if (b47s->bcma_cc->core->id.rev < 20) {
+               bcm47xxsflash_cmd(b47s, OPCODE_ST_PP);
+               return 1; /* 1B written */
+       }
+
+       /* Program page and set CSA (on newer chips we can continue writing) */
+       bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | OPCODE_ST_PP);
+       offset++;
+       len--;
+       written++;
+
+       while (len > 0) {
+               /* Page boundary, another function call is needed */
+               if ((offset & 0xFF) == 0)
+                       break;
+
+               bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | *buf++);
+               offset++;
+               len--;
+               written++;
+       }
+
+       /* All done, drop CSA & poll */
+       b47s->cc_write(b47s, BCMA_CC_FLASHCTL, 0);
+       udelay(1);
+       if (bcm47xxsflash_poll(b47s, HZ / 10))
+               pr_err("Flash rejected dropping CSA\n");
+
+       return written;
+}
+
+static int bcm47xxsflash_write_at(struct mtd_info *mtd, u32 offset, size_t len,
+                                 const u_char *buf)
+{
+       struct bcm47xxsflash *b47s = mtd->priv;
+       u32 mask = b47s->blocksize - 1;
+       u32 page = (offset & ~mask) << 1;
+       u32 byte = offset & mask;
+       int written = 0;
+
+       /* If we don't overwrite whole page, read it to the buffer first */
+       if (byte || (len < b47s->blocksize)) {
+               int err;
+
+               b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
+               bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_LOAD);
+               /* 250 us for AT45DB321B */
+               err = bcm47xxsflash_poll(b47s, HZ / 1000);
+               if (err) {
+                       pr_err("Timeout reading page 0x%X info buffer\n", page);
+                       return err;
+               }
+       }
+
+       /* Change buffer content with our data */
+       while (len > 0) {
+               /* Page boundary, another function call is needed */
+               if (byte == b47s->blocksize)
+                       break;
+
+               b47s->cc_write(b47s, BCMA_CC_FLASHADDR, byte++);
+               b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
+               bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_WRITE);
+               len--;
+               written++;
+       }
+
+       /* Program page with the buffer content */
+       b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
+       bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_PROGRAM);
+
+       return written;
+}
+
+static int bcm47xxsflash_write(struct mtd_info *mtd, loff_t to, size_t len,
+                              size_t *retlen, const u_char *buf)
+{
+       struct bcm47xxsflash *b47s = mtd->priv;
+       int written;
+
+       /* Writing functions can return without writing all passed data, for
+        * example when the hardware is too old or when we git page boundary.
+        */
+       while (len > 0) {
+               switch (b47s->type) {
+               case BCM47XXSFLASH_TYPE_ST:
+                       written = bcm47xxsflash_write_st(mtd, to, len, buf);
+                       break;
+               case BCM47XXSFLASH_TYPE_ATMEL:
+                       written = bcm47xxsflash_write_at(mtd, to, len, buf);
+                       break;
+               default:
+                       BUG_ON(1);
+               }
+               if (written < 0) {
+                       pr_err("Error writing at offset 0x%llX\n", to);
+                       return written;
+               }
+               to += (loff_t)written;
+               len -= written;
+               *retlen += written;
+               buf += written;
+       }
+
+       return 0;
+}
+
 static void bcm47xxsflash_fill_mtd(struct bcm47xxsflash *b47s)
 {
        struct mtd_info *mtd = &b47s->mtd;
@@ -123,16 +244,17 @@ static void bcm47xxsflash_fill_mtd(struct bcm47xxsflash *b47s)
        mtd->priv = b47s;
        mtd->name = "bcm47xxsflash";
        mtd->owner = THIS_MODULE;
-       mtd->type = MTD_ROM;
 
-       /* TODO: implement writing support and verify/change following code */
-       mtd->flags = MTD_CAP_ROM;
+       mtd->type = MTD_NORFLASH;
+       mtd->flags = MTD_CAP_NORFLASH;
        mtd->size = b47s->size;
        mtd->erasesize = b47s->blocksize;
-       mtd->writebufsize = mtd->writesize = 1;
+       mtd->writesize = 1;
+       mtd->writebufsize = 1;
 
        mtd->_erase = bcm47xxsflash_erase;
        mtd->_read = bcm47xxsflash_read;
+       mtd->_write = bcm47xxsflash_write;
 }
 
 /**************************************************