[v6,2/3] mtd: nand: raw: qcom_nandc: add support for unprotected spare data pages

diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
index 7fbbd3e7784c..29a16534bee3 100644
--- a/drivers/mtd/nand/raw/qcom_nandc.c
+++ b/drivers/mtd/nand/raw/qcom_nandc.c
@@ -80,8 +80,10 @@ 
 #define	DISABLE_STATUS_AFTER_WRITE	4
 #define	CW_PER_PAGE			6
 #define	UD_SIZE_BYTES			9
+#define	UD_SIZE_BYTES_MASK		GENMASK(18, 9)
 #define	ECC_PARITY_SIZE_BYTES_RS	19
 #define	SPARE_SIZE_BYTES		23
+#define	SPARE_SIZE_BYTES_MASK		GENMASK(26, 23)
 #define	NUM_ADDR_CYCLES			27
 #define	STATUS_BFR_READ			30
 #define	SET_RD_MODE_AFTER_STATUS	31
@@ -102,6 +104,7 @@ 
 #define	ECC_MODE			4
 #define	ECC_PARITY_SIZE_BYTES_BCH	8
 #define	ECC_NUM_DATA_BYTES		16
+#define	ECC_NUM_DATA_BYTES_MASK		GENMASK(25, 16)
 #define	ECC_FORCE_CLK_OPEN		30
 
 /* NAND_DEV_CMD1 bits */
@@ -418,6 +421,19 @@  struct qcom_nand_controller {
 	const struct qcom_nandc_props *props;
 };
 
+/*
+ * NAND special boot partitions
+ *
+ * @page_offset:		offset of the partition where spare data is not protected
+ *				by ECC (value in pages)
+ * @page_offset:		size of the partition where spare data is not protected
+ *				by ECC (value in pages)
+ */
+struct qcom_nand_boot_partition {
+	u32 page_offset;
+	u32 page_size;
+};
+
 /*
  * NAND chip structure
  *
@@ -434,6 +450,8 @@  struct qcom_nand_controller {
  * @ecc_bytes_hw:		ECC bytes used by controller hardware for this
  *				chip
  *
+ * @codeword_fixup:		keep track of the current layout used by
+ *				the driver for read/write operation.
  * @use_ecc:			request the controller to use ECC for the
  *				upcoming read/write
  * @bch_enabled:		flag to tell whether BCH ECC mode is used
@@ -445,6 +463,11 @@  struct qcom_nand_controller {
  * @cfg0, cfg1, cfg0_raw..:	NANDc register configurations needed for
  *				ecc/non-ecc mode for the current nand flash
  *				device
+ *
+ * @nr_boot_partitions:		count of the boot partitions where spare data is not
+ *				protected by ECC
+ * @boot_partitions:		array of boot partitions where offset and size of the
+ *				boot partitions are stored
  */
 struct qcom_nand_host {
 	struct nand_chip chip;
@@ -457,6 +480,7 @@  struct qcom_nand_host {
 	int spare_bytes;
 	int bbm_size;
 
+	bool codeword_fixup;
 	bool use_ecc;
 	bool bch_enabled;
 	u8 status;
@@ -468,6 +492,9 @@  struct qcom_nand_host {
 	u32 ecc_bch_cfg;
 	u32 clrflashstatus;
 	u32 clrreadstatus;
+
+	int nr_boot_partitions;
+	struct qcom_nand_boot_partition *boot_partitions;
 };
 
 /*
@@ -477,6 +504,7 @@  struct qcom_nand_host {
  * @is_bam - whether NAND controller is using BAM
  * @is_qpic - whether NAND CTRL is part of qpic IP
  * @qpic_v2 - flag to indicate QPIC IP version 2
+ * @use_codeword_fixup - whether NAND has different layout for boot partitions
  * @dev_cmd_reg_start - NAND_DEV_CMD_* registers starting offset
  */
 struct qcom_nandc_props {
@@ -484,6 +512,7 @@  struct qcom_nandc_props {
 	bool is_bam;
 	bool is_qpic;
 	bool qpic_v2;
+	bool use_codeword_fixup;
 	u32 dev_cmd_reg_start;
 };
 
@@ -1703,7 +1732,7 @@  qcom_nandc_read_cw_raw(struct mtd_info *mtd, struct nand_chip *chip,
 	data_size1 = mtd->writesize - host->cw_size * (ecc->steps - 1);
 	oob_size1 = host->bbm_size;
 
-	if (qcom_nandc_is_last_cw(ecc, cw)) {
+	if (qcom_nandc_is_last_cw(ecc, cw) && !host->codeword_fixup) {
 		data_size2 = ecc->size - data_size1 -
 			     ((ecc->steps - 1) * 4);
 		oob_size2 = (ecc->steps * 4) + host->ecc_bytes_hw +
@@ -1784,7 +1813,7 @@  check_for_erased_page(struct qcom_nand_host *host, u8 *data_buf,
 	}
 
 	for_each_set_bit(cw, &uncorrectable_cws, ecc->steps) {
-		if (qcom_nandc_is_last_cw(ecc, cw)) {
+		if (qcom_nandc_is_last_cw(ecc, cw) && !host->codeword_fixup) {
 			data_size = ecc->size - ((ecc->steps - 1) * 4);
 			oob_size = (ecc->steps * 4) + host->ecc_bytes_hw;
 		} else {
@@ -1942,7 +1971,7 @@  static int read_page_ecc(struct qcom_nand_host *host, u8 *data_buf,
 	for (i = 0; i < ecc->steps; i++) {
 		int data_size, oob_size;
 
-		if (qcom_nandc_is_last_cw(ecc, i)) {
+		if (qcom_nandc_is_last_cw(ecc, i) && !host->codeword_fixup) {
 			data_size = ecc->size - ((ecc->steps - 1) << 2);
 			oob_size = (ecc->steps << 2) + host->ecc_bytes_hw +
 				   host->spare_bytes;
@@ -2039,6 +2068,78 @@  static int copy_last_cw(struct qcom_nand_host *host, int page)
 	return ret;
 }
 
+static bool qcom_nandc_is_boot_partition(struct qcom_nand_host *host, int page)
+{
+	struct qcom_nand_boot_partition *boot_partition;
+	u32 start, end;
+	int i;
+
+	/*
+	 * Since the frequent access will be to the non-boot partitions like rootfs,
+	 * optimize the page check by:
+
+	 * 1. Checking if the page lies after the last boot partition.
+	 * 2. Checking from the boot partition end.
+	 *
+	 * This comes from the fact that an example partition table is:
+	 * mtd0: 00c80000 00020000 "qcadata"	(require codeword fix)
+	 * mtd1: 00500000 00020000 "APPSBL"	(require codeword fix)
+	 * mtd2: 00080000 00020000 "APPSBLENV"	(doesn't require codeword fix)
+	 * mtd3: 00140000 00020000 "art"	(doesn't require codeword fix)
+	 * mtd4: 00140000 00020000 "artbak"	(doesn't require codeword fix)
+	 * mtd5: 00400000 00020000 "kernel"	(doesn't require codeword fix)
+	 * mtd6: 06080000 00020000 "ubi"	(doesn't require codeword fix)
+	 * mtd7: 00700000 00020000 "reserve"	(doesn't require codeword fix)
+	 *
+	 * where the boot partition are always the first partition and rootfs
+	 * partition are at the end.
+	 *
+	 * Defining a big single boot partition is not possible since some
+	 * device have the following partition table:
+	 * mtd0: 00c80000 00020000 "qcadata" (require codeword fix)
+	 * mtd1: 00500000 00020000 "APPSBL"  (require codeword fix)
+	 * mtd2: 00080000 00020000 "APPSBLENV" (doesn't require codeword fix)
+	 * mtd3: 00140000 00020000 "APPSBL2"  (require codeword fix)
+	 *
+	 * where a backup partition is placed after a partition where the
+	 * codeword fix should not be used.
+	 */
+	for (i = host->nr_boot_partitions - 1; i >= 0; i--) {
+		boot_partition = &host->boot_partitions[i];
+		start = boot_partition->page_offset;
+		end = start + boot_partition->page_size;
+
+		if (page < end && page >= start)
+			return true;
+	}
+
+	return false;
+}
+
+static void
+qcom_nandc_codeword_fixup(struct qcom_nand_host *host, int page)
+{
+	bool codeword_fixup = qcom_nandc_is_boot_partition(host, page);
+
+	/* Skip conf write if we are already in the correct mode */
+	if (codeword_fixup == host->codeword_fixup)
+		return;
+
+	host->codeword_fixup = codeword_fixup;
+
+	host->cw_data = codeword_fixup ? 512 : 516;
+	host->spare_bytes = host->cw_size - host->ecc_bytes_hw -
+			    host->bbm_size - host->cw_data;
+
+	host->cfg0 &= ~(SPARE_SIZE_BYTES_MASK | UD_SIZE_BYTES_MASK);
+	host->cfg0 |= host->spare_bytes << SPARE_SIZE_BYTES |
+		      host->cw_data << UD_SIZE_BYTES;
+
+	host->ecc_bch_cfg &= ~ECC_NUM_DATA_BYTES_MASK;
+	host->ecc_bch_cfg |= host->cw_data << ECC_NUM_DATA_BYTES;
+	host->ecc_buf_cfg = (host->cw_data - 1) << NUM_STEPS;
+}
+
 /* implements ecc->read_page() */
 static int qcom_nandc_read_page(struct nand_chip *chip, uint8_t *buf,
 				int oob_required, int page)
@@ -2047,6 +2148,9 @@  static int qcom_nandc_read_page(struct nand_chip *chip, uint8_t *buf,
 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
 	u8 *data_buf, *oob_buf = NULL;
 
+	if (host->nr_boot_partitions)
+		qcom_nandc_codeword_fixup(host, page);
+
 	nand_read_page_op(chip, page, 0, NULL, 0);
 	data_buf = buf;
 	oob_buf = oob_required ? chip->oob_poi : NULL;
@@ -2066,6 +2170,9 @@  static int qcom_nandc_read_page_raw(struct nand_chip *chip, uint8_t *buf,
 	int cw, ret;
 	u8 *data_buf = buf, *oob_buf = chip->oob_poi;
 
+	if (host->nr_boot_partitions)
+		qcom_nandc_codeword_fixup(host, page);
+
 	for (cw = 0; cw < ecc->steps; cw++) {
 		ret = qcom_nandc_read_cw_raw(mtd, chip, data_buf, oob_buf,
 					     page, cw);
@@ -2086,6 +2193,9 @@  static int qcom_nandc_read_oob(struct nand_chip *chip, int page)
 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
 	struct nand_ecc_ctrl *ecc = &chip->ecc;
 
+	if (host->nr_boot_partitions)
+		qcom_nandc_codeword_fixup(host, page);
+
 	clear_read_regs(nandc);
 	clear_bam_transaction(nandc);
 
@@ -2106,6 +2216,9 @@  static int qcom_nandc_write_page(struct nand_chip *chip, const uint8_t *buf,
 	u8 *data_buf, *oob_buf;
 	int i, ret;
 
+	if (host->nr_boot_partitions)
+		qcom_nandc_codeword_fixup(host, page);
+
 	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
 
 	clear_read_regs(nandc);
@@ -2121,7 +2234,7 @@  static int qcom_nandc_write_page(struct nand_chip *chip, const uint8_t *buf,
 	for (i = 0; i < ecc->steps; i++) {
 		int data_size, oob_size;
 
-		if (qcom_nandc_is_last_cw(ecc, i)) {
+		if (qcom_nandc_is_last_cw(ecc, i) && !host->codeword_fixup) {
 			data_size = ecc->size - ((ecc->steps - 1) << 2);
 			oob_size = (ecc->steps << 2) + host->ecc_bytes_hw +
 				   host->spare_bytes;
@@ -2178,6 +2291,9 @@  static int qcom_nandc_write_page_raw(struct nand_chip *chip,
 	u8 *data_buf, *oob_buf;
 	int i, ret;
 
+	if (host->nr_boot_partitions)
+		qcom_nandc_codeword_fixup(host, page);
+
 	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
 	clear_read_regs(nandc);
 	clear_bam_transaction(nandc);
@@ -2196,7 +2312,7 @@  static int qcom_nandc_write_page_raw(struct nand_chip *chip,
 		data_size1 = mtd->writesize - host->cw_size * (ecc->steps - 1);
 		oob_size1 = host->bbm_size;
 
-		if (qcom_nandc_is_last_cw(ecc, i)) {
+		if (qcom_nandc_is_last_cw(ecc, i) && !host->codeword_fixup) {
 			data_size2 = ecc->size - data_size1 -
 				     ((ecc->steps - 1) << 2);
 			oob_size2 = (ecc->steps << 2) + host->ecc_bytes_hw +
@@ -2256,6 +2372,9 @@  static int qcom_nandc_write_oob(struct nand_chip *chip, int page)
 	int data_size, oob_size;
 	int ret;
 
+	if (host->nr_boot_partitions)
+		qcom_nandc_codeword_fixup(host, page);
+
 	host->use_ecc = true;
 	clear_bam_transaction(nandc);
 
@@ -2904,6 +3023,74 @@  static int qcom_nandc_setup(struct qcom_nand_controller *nandc)
 
 static const char * const probes[] = { "cmdlinepart", "ofpart", "qcomsmem", NULL };
 
+static int qcom_nand_host_parse_boot_partitions(struct qcom_nand_controller *nandc,
+						struct qcom_nand_host *host,
+						struct device_node *dn)
+{
+	struct nand_chip *chip = &host->chip;
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	struct qcom_nand_boot_partition *boot_partition;
+	struct device *dev = nandc->dev;
+	int partitions_count, i, j, ret;
+
+	if (!of_find_property(dn, "qcom,boot-partitions", NULL))
+		return 0;
+
+	partitions_count = of_property_count_u32_elems(dn, "qcom,boot-partitions");
+	if (partitions_count <= 0) {
+		dev_err(dev, "Error parsing boot partition\n");
+		return ret;
+	}
+
+	host->nr_boot_partitions = partitions_count / 2;
+	host->boot_partitions = devm_kcalloc(dev, host->nr_boot_partitions,
+					     sizeof(*host->boot_partitions), GFP_KERNEL);
+	if (!host->boot_partitions) {
+		host->nr_boot_partitions = 0;
+		return -ENOMEM;
+	}
+
+	for (i = 0, j = 0; i < host->nr_boot_partitions; i++, j += 2) {
+		boot_partition = &host->boot_partitions[i];
+
+		ret = of_property_read_u32_index(dn, "qcom,boot-partitions", j,
+						 &boot_partition->page_offset);
+		if (ret) {
+			dev_err(dev, "Error parsing boot partition offset at index %d", i);
+			host->nr_boot_partitions = 0;
+			return ret;
+		}
+
+		if (boot_partition->page_offset % mtd->writesize) {
+			dev_err(dev, "Boot partition offset not multiple of writesize at index %i\n",
+				i);
+			host->nr_boot_partitions = 0;
+			return -EINVAL;
+		}
+		/* Convert offset to nand pages */
+		boot_partition->page_offset /= mtd->writesize;
+
+		ret = of_property_read_u32_index(dn, "qcom,boot-partitions", j + 1,
+						 &boot_partition->page_size);
+		if (ret) {
+			dev_err(dev, "Error parsing boot partition size at index %d\n", i);
+			host->nr_boot_partitions = 0;
+			return ret;
+		}
+
+		if (boot_partition->page_size % mtd->writesize) {
+			dev_err(dev, "Boot partition size not multiple of writesize at index %i",
+				i);
+			host->nr_boot_partitions = 0;
+			return -EINVAL;
+		}
+		/* Convert size to nand pages */
+		boot_partition->page_size /= mtd->writesize;
+	}
+
+	return 0;
+}
+
 static int qcom_nand_host_init_and_register(struct qcom_nand_controller *nandc,
 					    struct qcom_nand_host *host,
 					    struct device_node *dn)
@@ -2972,6 +3159,12 @@  static int qcom_nand_host_init_and_register(struct qcom_nand_controller *nandc,
 	if (ret)
 		nand_cleanup(chip);
 
+	if (nandc->props->use_codeword_fixup) {
+		ret = qcom_nand_host_parse_boot_partitions(nandc, host, dn);
+		if (ret)
+			return ret;
+	}
+
 	return ret;
 }
 
@@ -3137,6 +3330,7 @@  static int qcom_nandc_remove(struct platform_device *pdev)
 static const struct qcom_nandc_props ipq806x_nandc_props = {
 	.ecc_modes = (ECC_RS_4BIT | ECC_BCH_8BIT),
 	.is_bam = false,
+	.use_codeword_fixup = true,
 	.dev_cmd_reg_start = 0x0,
 };