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Commit af744750 authored by Christian Riesch's avatar Christian Riesch Committed by Brian Norris
Browse files

mtd: cfi_cmdset_0002: Add support for writing OTP memory 



This patch adds support for writing the one time programmable (OTP)
memory of Micron M29EW devices.

Signed-off-by: default avatarChristian Riesch <christian.riesch@omicron.at>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent feb86779

drivers/mtd/chips/cfi_cmdset_0002.c

+60 −7
Original line number Diff line number Diff line
@@ -67,6 +67,8 @@ static int cfi_amdstd_read_fact_prot_reg(struct mtd_info *, loff_t, size_t, 
					 size_t *, u_char *);

static int cfi_amdstd_read_user_prot_reg(struct mtd_info *, loff_t, size_t,

					 size_t *, u_char *);

static int cfi_amdstd_write_user_prot_reg(struct mtd_info *, loff_t, size_t,

					  size_t *, u_char *);



static int cfi_amdstd_panic_write(struct mtd_info *mtd, loff_t to, size_t len,

				  size_t *retlen, const u_char *buf);
@@ -530,6 +532,7 @@ struct mtd_info *cfi_cmdset_0002(struct map_info *map, int primary) 
	mtd->_read_fact_prot_reg = cfi_amdstd_read_fact_prot_reg;

	mtd->_get_fact_prot_info = cfi_amdstd_get_fact_prot_info;

	mtd->_get_user_prot_info = cfi_amdstd_get_user_prot_info;

	mtd->_write_user_prot_reg = cfi_amdstd_write_user_prot_reg;

	mtd->flags   = MTD_CAP_NORFLASH;

	mtd->name    = map->name;

	mtd->writesize = 1;
@@ -1257,6 +1260,40 @@ static int cfi_amdstd_secsi_read (struct mtd_info *mtd, loff_t from, size_t len, 
	return ret;

}



static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,

				     unsigned long adr, map_word datum,

				     int mode);



static int do_otp_write(struct map_info *map, struct flchip *chip, loff_t adr,

			size_t len, u_char *buf)

{

	int ret;

	while (len) {

		unsigned long bus_ofs = adr & ~(map_bankwidth(map)-1);

		int gap = adr - bus_ofs;

		int n = min_t(int, len, map_bankwidth(map) - gap);

		map_word datum;



		if (n != map_bankwidth(map)) {

			/* partial write of a word, load old contents */

			otp_enter(map, chip, bus_ofs, map_bankwidth(map));

			datum = map_read(map, bus_ofs);

			otp_exit(map, chip, bus_ofs, map_bankwidth(map));

		}



		datum = map_word_load_partial(map, datum, buf, gap, n);

		ret = do_write_oneword(map, chip, bus_ofs, datum, FL_OTP_WRITE);

		if (ret)

			return ret;



		adr += n;

		buf += n;

		len -= n;

	}



	return 0;

}



static int cfi_amdstd_otp_walk(struct mtd_info *mtd, loff_t from, size_t len,

			       size_t *retlen, u_char *buf,

			       otp_op_t action, int user_regs)
@@ -1400,7 +1437,17 @@ static int cfi_amdstd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, 
				   buf, do_read_secsi_onechip, 1);

}



static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip, unsigned long adr, map_word datum)

static int cfi_amdstd_write_user_prot_reg(struct mtd_info *mtd, loff_t from,

					  size_t len, size_t *retlen,

					  u_char *buf)

{

	return cfi_amdstd_otp_walk(mtd, from, len, retlen, buf,

				   do_otp_write, 1);

}



static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,

				     unsigned long adr, map_word datum,

				     int mode)

{

	struct cfi_private *cfi = map->fldrv_priv;

	unsigned long timeo = jiffies + HZ;
@@ -1421,7 +1468,7 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip, 
	adr += chip->start;



	mutex_lock(&chip->mutex);

	ret = get_chip(map, chip, adr, FL_WRITING);

	ret = get_chip(map, chip, adr, mode);

	if (ret) {

		mutex_unlock(&chip->mutex);

		return ret;
@@ -1430,6 +1477,9 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip, 
	pr_debug("MTD %s(): WRITE 0x%.8lx(0x%.8lx)\n",

	       __func__, adr, datum.x[0] );



	if (mode == FL_OTP_WRITE)

		otp_enter(map, chip, adr, map_bankwidth(map));



	/*

	 * Check for a NOP for the case when the datum to write is already

	 * present - it saves time and works around buggy chips that corrupt
@@ -1446,12 +1496,13 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip, 
	XIP_INVAL_CACHED_RANGE(map, adr, map_bankwidth(map));

	ENABLE_VPP(map);

	xip_disable(map, chip, adr);



 retry:

	cfi_send_gen_cmd(0xAA, cfi->addr_unlock1, chip->start, map, cfi, cfi->device_type, NULL);

	cfi_send_gen_cmd(0x55, cfi->addr_unlock2, chip->start, map, cfi, cfi->device_type, NULL);

	cfi_send_gen_cmd(0xA0, cfi->addr_unlock1, chip->start, map, cfi, cfi->device_type, NULL);

	map_write(map, datum, adr);

	chip->state = FL_WRITING;

	chip->state = mode;



	INVALIDATE_CACHE_UDELAY(map, chip,

				adr, map_bankwidth(map),
@@ -1460,7 +1511,7 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip, 
	/* See comment above for timeout value. */

	timeo = jiffies + uWriteTimeout;

	for (;;) {

		if (chip->state != FL_WRITING) {

		if (chip->state != mode) {

			/* Someone's suspended the write. Sleep */

			DECLARE_WAITQUEUE(wait, current);
@@ -1500,6 +1551,8 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip, 
	}

	xip_enable(map, chip, adr);

 op_done:

	if (mode == FL_OTP_WRITE)

		otp_exit(map, chip, adr, map_bankwidth(map));

	chip->state = FL_READY;

	DISABLE_VPP(map);

	put_chip(map, chip, adr);
@@ -1555,7 +1608,7 @@ static int cfi_amdstd_write_words(struct mtd_info *mtd, loff_t to, size_t len, 
		tmp_buf = map_word_load_partial(map, tmp_buf, buf, i, n);



		ret = do_write_oneword(map, &cfi->chips[chipnum],

				       bus_ofs, tmp_buf);

				       bus_ofs, tmp_buf, FL_WRITING);

		if (ret)

			return ret;
@@ -1579,7 +1632,7 @@ static int cfi_amdstd_write_words(struct mtd_info *mtd, loff_t to, size_t len, 
		datum = map_word_load(map, buf);



		ret = do_write_oneword(map, &cfi->chips[chipnum],

				       ofs, datum);

				       ofs, datum, FL_WRITING);

		if (ret)

			return ret;
@@ -1622,7 +1675,7 @@ static int cfi_amdstd_write_words(struct mtd_info *mtd, loff_t to, size_t len, 
		tmp_buf = map_word_load_partial(map, tmp_buf, buf, 0, len);



		ret = do_write_oneword(map, &cfi->chips[chipnum],

				ofs, tmp_buf);

				       ofs, tmp_buf, FL_WRITING);

		if (ret)

			return ret;