[PATCH v2] mtd: rawnand: Add Macronix NAND read retry support

[Mason Yang]

Add support for Macronix NAND read retry.

Macronix NANDs support specific read operation for data recovery,
which can be enabled/disabled with a SET/GET_FEATURE.
Driver checks byte 167 of Vendor Blocks in ONFI parameter page table
to see if this high-reliability function is supported.

Signed-off-by: Mason Yang <masonccyang@xxxxxxxxxxx>
---
 drivers/mtd/nand/raw/nand_macronix.c | 57 ++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/drivers/mtd/nand/raw/nand_macronix.c b/drivers/mtd/nand/raw/nand_macronix.c
index e287e71..1a4dc92 100644
--- a/drivers/mtd/nand/raw/nand_macronix.c
+++ b/drivers/mtd/nand/raw/nand_macronix.c
@@ -17,6 +17,62 @@
 
 #include "internals.h"
 
+#define MACRONIX_READ_RETRY_BIT BIT(0)
+#define MACRONIX_READ_RETRY_MODE 6
+
+struct nand_onfi_vendor_macronix {
+	u8 reserved[1];
+	u8 reliability_func;
+} __packed;
+
+/*
+ * Macronix NANDs support using SET/GET_FEATURES to enter/exit read retry mode
+ */
+static int macronix_nand_setup_read_retry(struct nand_chip *chip, int mode)
+{
+	u8 feature[ONFI_SUBFEATURE_PARAM_LEN];
+	int ret, feature_addr = ONFI_FEATURE_ADDR_READ_RETRY;
+
+	if (chip->parameters.supports_set_get_features &&
+	    test_bit(feature_addr, chip->parameters.set_feature_list) &&
+	    test_bit(feature_addr, chip->parameters.get_feature_list)) {
+		feature[0] = mode;
+		ret =  nand_set_features(chip, feature_addr, feature);
+		if (ret)
+			pr_err("Failed to set read retry moded:%d\n", mode);
+
+		ret =  nand_get_features(chip, feature_addr, feature);
+		if (ret || feature[0] != mode)
+			pr_err("Failed to verify read retry moded:%d(%d)\n",
+			       mode, feature[0]);
+	}
+
+	return ret;
+}
+
+static void macronix_nand_onfi_init(struct nand_chip *chip)
+{
+	struct nand_parameters *p = &chip->parameters;
+	struct nand_onfi_vendor_macronix *mxic;
+
+	if (!p->onfi)
+		return;
+
+	mxic = (struct nand_onfi_vendor_macronix *)p->onfi->vendor;
+	if ((mxic->reliability_func & MACRONIX_READ_RETRY_BIT) == 0)
+		return;
+
+	chip->read_retries = MACRONIX_READ_RETRY_MODE;
+	chip->setup_read_retry = macronix_nand_setup_read_retry;
+
+	if (p->supports_set_get_features) {
+		bitmap_set(p->set_feature_list,
+			   ONFI_FEATURE_ADDR_READ_RETRY, 1);
+		bitmap_set(p->get_feature_list,
+			   ONFI_FEATURE_ADDR_READ_RETRY, 1);
+	}
+}
+
 /*
  * Macronix AC series does not support using SET/GET_FEATURES to change
  * the timings unlike what is declared in the parameter page. Unflag
@@ -65,6 +121,7 @@ static int macronix_nand_init(struct nand_chip *chip)
 		chip->options |= NAND_BBM_FIRSTPAGE | NAND_BBM_SECONDPAGE;
 
 	macronix_nand_fix_broken_get_timings(chip);
+	macronix_nand_onfi_init(chip);
 
 	return 0;
 }
-- 
1.9.1