mtd: nand: ecc-bch: Stop using raw NAND structures

This code is meant to be reused by the SPI-NAND core. Now that the
driver has been cleaned and reorganized, use a generic ECC engine
object to store the driver's data instead of accessing members of the
nand_chip structure.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200929230124.31491-9-miquel.raynal@bootlin.com

Author: miquelraynal

drivers/mtd/nand/ecc-sw-bch.c

@@ -11,23 +11,8 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/bitops.h>
-#include <linux/mtd/mtd.h>
-#include <linux/mtd/rawnand.h>
 #include <linux/mtd/nand.h>
 #include <linux/mtd/nand-ecc-sw-bch.h>
-#include <linux/bch.h>
-
-/**
- * struct nand_bch_control - private NAND BCH control structure
- * @bch:       BCH control structure
- * @errloc:    error location array
- * @eccmask:   XOR ecc mask, allows erased pages to be decoded as valid
- */
-struct nand_bch_control {
-	struct bch_control   *bch;
-	unsigned int         *errloc;
-	unsigned char        *eccmask;
-};
 
 /**
  * nand_ecc_sw_bch_calculate - Calculate the ECC corresponding to a data block
@@ -38,16 +23,15 @@ struct nand_bch_control {
 int nand_ecc_sw_bch_calculate(struct nand_device *nand,
 			      const unsigned char *buf, unsigned char *code)
 {
-	struct nand_chip *chip = mtd_to_nand(nanddev_to_mtd(nand));
-	struct nand_bch_control *nbc = chip->ecc.priv;
+	struct nand_ecc_sw_bch_conf *engine_conf = nand->ecc.ctx.priv;
 	unsigned int i;
 
-	memset(code, 0, chip->ecc.bytes);
-	bch_encode(nbc->bch, buf, chip->ecc.size, code);
+	memset(code, 0, engine_conf->code_size);
+	bch_encode(engine_conf->bch, buf, nand->ecc.ctx.conf.step_size, code);
 
 	/* apply mask so that an erased page is a valid codeword */
-	for (i = 0; i < chip->ecc.bytes; i++)
-		code[i] ^= nbc->eccmask[i];
+	for (i = 0; i < engine_conf->code_size; i++)
+		code[i] ^= engine_conf->eccmask[i];
 
 	return 0;
 }
@@ -65,16 +49,16 @@ EXPORT_SYMBOL(nand_ecc_sw_bch_calculate);
 int nand_ecc_sw_bch_correct(struct nand_device *nand, unsigned char *buf,
 			    unsigned char *read_ecc, unsigned char *calc_ecc)
 {
-	struct nand_chip *chip = mtd_to_nand(nanddev_to_mtd(nand));
-	struct nand_bch_control *nbc = chip->ecc.priv;
-	unsigned int *errloc = nbc->errloc;
+	struct nand_ecc_sw_bch_conf *engine_conf = nand->ecc.ctx.priv;
+	unsigned int step_size = nand->ecc.ctx.conf.step_size;
+	unsigned int *errloc = engine_conf->errloc;
 	int i, count;
 
-	count = bch_decode(nbc->bch, NULL, chip->ecc.size, read_ecc, calc_ecc,
-			   NULL, errloc);
+	count = bch_decode(engine_conf->bch, NULL, step_size, read_ecc,
+			   calc_ecc, NULL, errloc);
 	if (count > 0) {
 		for (i = 0; i < count; i++) {
-			if (errloc[i] < (chip->ecc.size * 8))
+			if (errloc[i] < (step_size * 8))
 				/* The error is in the data area: correct it */
 				buf[errloc[i] >> 3] ^= (1 << (errloc[i] & 7));
 
@@ -97,31 +81,30 @@ EXPORT_SYMBOL(nand_ecc_sw_bch_correct);
  *
  * Returns: a pointer to a new NAND BCH control structure, or NULL upon failure
  *
- * Initialize NAND BCH error correction. Parameters @eccsize and @eccbytes
- * are used to compute the following BCH parameters:
+ * Initialize NAND BCH error correction. @nand.ecc parameters 'step_size' and
+ * 'bytes' are used to compute the following BCH parameters:
  *     m, the Galois field order
  *     t, the error correction capability
- * @eccbytes should be equal to the number of bytes required to store m * t
+ * 'bytes' should be equal to the number of bytes required to store m * t
  * bits, where m is such that 2^m - 1 > step_size * 8.
  *
  * Example: to configure 4 bit correction per 512 bytes, you should pass
- * @eccsize = 512 (thus, m = 13 is the smallest integer such that 2^m - 1 > 512 * 8)
- * @eccbytes = 7 (7 bytes are required to store m * t = 13 * 4 = 52 bits)
+ * step_size = 512 (thus, m = 13 is the smallest integer such that 2^m - 1 > 512 * 8)
+ * bytes = 7 (7 bytes are required to store m * t = 13 * 4 = 52 bits)
  */
 int nand_ecc_sw_bch_init(struct nand_device *nand)
 {
 	struct mtd_info *mtd = nanddev_to_mtd(nand);
-	struct nand_chip *chip = mtd_to_nand(mtd);
 	unsigned int m, t, eccsteps, i;
-	struct nand_bch_control *nbc = NULL;
+	struct nand_ecc_sw_bch_conf *engine_conf = nand->ecc.ctx.priv;
 	unsigned char *erased_page;
-	unsigned int eccsize = chip->ecc.size;
-	unsigned int eccbytes = chip->ecc.bytes;
-	unsigned int eccstrength = chip->ecc.strength;
+	unsigned int eccsize = nand->ecc.ctx.conf.step_size;
+	unsigned int eccbytes = engine_conf->code_size;
+	unsigned int eccstrength = nand->ecc.ctx.conf.strength;
 
 	if (!eccbytes && eccstrength) {
 		eccbytes = DIV_ROUND_UP(eccstrength * fls(8 * eccsize), 8);
-		chip->ecc.bytes = eccbytes;
+		engine_conf->code_size = eccbytes;
 	}
 
 	if (!eccsize || !eccbytes) {
@@ -132,20 +115,14 @@ int nand_ecc_sw_bch_init(struct nand_device *nand)
 	m = fls(1+8*eccsize);
 	t = (eccbytes*8)/m;
 
-	nbc = kzalloc(sizeof(*nbc), GFP_KERNEL);
-	if (!nbc)
-		return -ENOMEM;
-
-	chip->ecc.priv = nbc;
-
-	nbc->bch = bch_init(m, t, 0, false);
-	if (!nbc->bch)
-		goto fail;
+	engine_conf->bch = bch_init(m, t, 0, false);
+	if (!engine_conf->bch)
+		return -EINVAL;
 
 	/* verify that eccbytes has the expected value */
-	if (nbc->bch->ecc_bytes != eccbytes) {
+	if (engine_conf->bch->ecc_bytes != eccbytes) {
 		pr_warn("invalid eccbytes %u, should be %u\n",
-			eccbytes, nbc->bch->ecc_bytes);
+			eccbytes, engine_conf->bch->ecc_bytes);
 		goto fail;
 	}
 
@@ -163,25 +140,15 @@ int nand_ecc_sw_bch_init(struct nand_device *nand)
 		goto fail;
 	}
 
-	/*
-	 * ecc->steps and ecc->total might be used by mtd->ooblayout->ecc(),
-	 * which is called by mtd_ooblayout_count_eccbytes().
-	 * Make sure they are properly initialized before calling
-	 * mtd_ooblayout_count_eccbytes().
-	 * FIXME: we should probably rework the sequencing in nand_scan_tail()
-	 * to avoid setting those fields twice.
-	 */
-	chip->ecc.steps = eccsteps;
-	chip->ecc.total = eccsteps * eccbytes;
-	nand->base.ecc.ctx.total = chip->ecc.total;
 	if (mtd_ooblayout_count_eccbytes(mtd) != (eccsteps*eccbytes)) {
 		pr_warn("invalid ecc layout\n");
 		goto fail;
 	}
 
-	nbc->eccmask = kzalloc(eccbytes, GFP_KERNEL);
-	nbc->errloc = kmalloc_array(t, sizeof(*nbc->errloc), GFP_KERNEL);
-	if (!nbc->eccmask || !nbc->errloc)
+	engine_conf->eccmask = kzalloc(eccbytes, GFP_KERNEL);
+	engine_conf->errloc = kmalloc_array(t, sizeof(*engine_conf->errloc),
+					    GFP_KERNEL);
+	if (!engine_conf->eccmask || !engine_conf->errloc)
 		goto fail;
 
 	/*
@@ -192,14 +159,15 @@ int nand_ecc_sw_bch_init(struct nand_device *nand)
 		goto fail;
 
 	memset(erased_page, 0xff, eccsize);
-	bch_encode(nbc->bch, erased_page, eccsize, nbc->eccmask);
+	bch_encode(engine_conf->bch, erased_page, eccsize,
+		   engine_conf->eccmask);
 	kfree(erased_page);
 
 	for (i = 0; i < eccbytes; i++)
-		nbc->eccmask[i] ^= 0xff;
+		engine_conf->eccmask[i] ^= 0xff;
 
 	if (!eccstrength)
-		chip->ecc.strength = (eccbytes * 8) / fls(8 * eccsize);
+		nand->ecc.ctx.conf.strength = (eccbytes * 8) / fls(8 * eccsize);
 
 	return 0;
 
@@ -216,14 +184,12 @@ EXPORT_SYMBOL(nand_ecc_sw_bch_init);
  */
 void nand_ecc_sw_bch_cleanup(struct nand_device *nand)
 {
-	struct nand_chip *chip = mtd_to_nand(nanddev_to_mtd(nand));
-	struct nand_bch_control *nbc = chip->ecc.priv;
-
-	if (nbc) {
-		bch_free(nbc->bch);
-		kfree(nbc->errloc);
-		kfree(nbc->eccmask);
-		kfree(nbc);
+	struct nand_ecc_sw_bch_conf *engine_conf = nand->ecc.ctx.priv;
+
+	if (engine_conf) {
+		bch_free(engine_conf->bch);
+		kfree(engine_conf->errloc);
+		kfree(engine_conf->eccmask);
 	}
 }
 EXPORT_SYMBOL(nand_ecc_sw_bch_cleanup);

drivers/mtd/nand/raw/nand_base.c

@@ -5142,8 +5142,33 @@ static void nand_scan_ident_cleanup(struct nand_chip *chip)
 int rawnand_sw_bch_init(struct nand_chip *chip)
 {
 	struct nand_device *base = &chip->base;
+	struct nand_ecc_sw_bch_conf *engine_conf;
+	int ret;
+
+	base->ecc.user_conf.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
+	base->ecc.user_conf.algo = NAND_ECC_ALGO_BCH;
+	base->ecc.user_conf.step_size = chip->ecc.size;
+	base->ecc.user_conf.strength = chip->ecc.strength;
+
+	engine_conf = kzalloc(sizeof(*engine_conf), GFP_KERNEL);
+	if (!engine_conf)
+		return -ENOMEM;
+
+	engine_conf->code_size = chip->ecc.bytes;
+
+	base->ecc.ctx.priv = engine_conf;
 
-	return nand_ecc_sw_bch_init(base);
+	ret = nand_ecc_sw_bch_init(base);
+	if (ret)
+		kfree(base->ecc.ctx.priv);
+
+	chip->ecc.size = base->ecc.ctx.conf.step_size;
+	chip->ecc.strength = base->ecc.ctx.conf.strength;
+	chip->ecc.total = base->ecc.ctx.total;
+	chip->ecc.steps = engine_conf->nsteps;
+	chip->ecc.bytes = engine_conf->code_size;
+
+	return ret;
 }
 EXPORT_SYMBOL(rawnand_sw_bch_init);
 
@@ -5171,7 +5196,7 @@ void rawnand_sw_bch_cleanup(struct nand_chip *chip)
 
 	nand_ecc_sw_bch_cleanup(base);
 
-	chip->ecc.priv = NULL;
+	kfree(base->ecc.ctx.priv);
 }
 EXPORT_SYMBOL(rawnand_sw_bch_cleanup);
 
@@ -5794,15 +5819,18 @@ static int nand_scan_tail(struct nand_chip *chip)
 	 * Set the number of read / write steps for one page depending on ECC
 	 * mode.
 	 */
-	ecc->steps = mtd->writesize / ecc->size;
+	if (!ecc->steps)
+		ecc->steps = mtd->writesize / ecc->size;
 	if (ecc->steps * ecc->size != mtd->writesize) {
 		WARN(1, "Invalid ECC parameters\n");
 		ret = -EINVAL;
 		goto err_nand_manuf_cleanup;
 	}
 
-	ecc->total = ecc->steps * ecc->bytes;
-	chip->base.ecc.ctx.total = ecc->total;
+	if (!ecc->total) {
+		ecc->total = ecc->steps * ecc->bytes;
+		chip->base.ecc.ctx.total = ecc->total;
+	}
 
 	if (ecc->total > mtd->oobsize) {
 		WARN(1, "Total number of ECC bytes exceeded oobsize\n");

include/linux/mtd/nand-ecc-sw-bch.h

@@ -9,6 +9,31 @@
 #define __MTD_NAND_ECC_SW_BCH_H__
 
 #include <linux/mtd/nand.h>
+#include <linux/bch.h>
+
+/**
+ * struct nand_ecc_sw_bch_conf - private software BCH ECC engine structure
+ * @reqooblen: Save the actual user OOB length requested before overwriting it
+ * @spare_oobbuf: Spare OOB buffer if none is provided
+ * @code_size: Number of bytes needed to store a code (one code per step)
+ * @nsteps: Number of steps
+ * @calc_buf: Buffer to use when calculating ECC bytes
+ * @code_buf: Buffer to use when reading (raw) ECC bytes from the chip
+ * @bch: BCH control structure
+ * @errloc: error location array
+ * @eccmask: XOR ecc mask, allows erased pages to be decoded as valid
+ */
+struct nand_ecc_sw_bch_conf {
+	unsigned int reqooblen;
+	void *spare_oobbuf;
+	unsigned int code_size;
+	unsigned int nsteps;
+	u8 *calc_buf;
+	u8 *code_buf;
+	struct bch_control *bch;
+	unsigned int *errloc;
+	unsigned char *eccmask;
+};
 
 #if IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_BCH)