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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
Subject: [RFC][PATCH] mtd: bcm47xxsflash: writing support
Date: Wed, 22 May 2013 14:39:02 +0200
---
drivers/mtd/devices/bcm47xxsflash.c | 130 +++++++++++++++++++++++++++++++++--
1 file changed, 126 insertions(+), 4 deletions(-)
--- a/drivers/mtd/devices/bcm47xxsflash.c
+++ b/drivers/mtd/devices/bcm47xxsflash.c
@@ -116,6 +116,127 @@ static int bcm47xxsflash_read(struct mtd
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(struc
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;
}
/**************************************************
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