[PATCH RFC 3/3] mtd: rawnand: Add support Macronix power down mode

[Mason Yang]

Macronix AD series support using power down command to
enter a minimum power consumption state.

MTD default _suspend/_resume function replacement by
manufacturer postponed initialization.

Signed-off-by: Mason Yang <masonccyang@xxxxxxxxxxx>
---
 drivers/mtd/nand/raw/nand_macronix.c | 78 +++++++++++++++++++++++++++++++++++-
 1 file changed, 77 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/nand_macronix.c b/drivers/mtd/nand/raw/nand_macronix.c
index 991c636..99a7b2e 100644
--- a/drivers/mtd/nand/raw/nand_macronix.c
+++ b/drivers/mtd/nand/raw/nand_macronix.c
@@ -15,6 +15,8 @@
 #define MXIC_BLOCK_PROTECTION_ALL_LOCK 0x38
 #define MXIC_BLOCK_PROTECTION_ALL_UNLOCK 0x0
 
+#define NAND_CMD_POWER_DOWN 0xB9
+
 struct nand_onfi_vendor_macronix {
 	u8 reserved;
 	u8 reliability_func;
@@ -78,6 +80,12 @@ static void macronix_nand_onfi_init(struct nand_chip *chip)
 		"MX30UF4G28AC",
 };
 
+static const char * const nand_power_down[] = {
+		"MX30LF1G28AD",
+		"MX30LF2G28AD",
+		"MX30LF4G28AD",
+};
+
 static void macronix_nand_fix_broken_get_timings(struct nand_chip *chip)
 {
 	unsigned int i;
@@ -144,8 +152,64 @@ static int mxic_nand_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 	return ret;
 }
 
+int nand_power_down_op(struct nand_chip *chip)
+{
+	int ret;
+
+	if (nand_has_exec_op(chip)) {
+		struct nand_op_instr instrs[] = {
+			NAND_OP_CMD(NAND_CMD_POWER_DOWN, 0),
+		};
+
+		struct nand_operation op = NAND_OPERATION(chip->cur_cs, instrs);
+
+		ret = nand_exec_op(chip, &op);
+		if (ret)
+			return ret;
+
+	} else {
+		chip->legacy.cmdfunc(chip, NAND_CMD_POWER_DOWN, -1, -1);
+	}
+
+	return 0;
+}
+
+static int mxic_nand_suspend(struct mtd_info *mtd)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+
+	mutex_lock(&chip->lock);
+
+	nand_select_target(chip, 0);
+	nand_power_down_op(chip);
+	nand_deselect_target(chip);
+
+	chip->suspend = 1;
+	mutex_unlock(&chip->lock);
+
+	return 0;
+}
+
+static void mxic_nand_resume(struct mtd_info *mtd)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+
+	mutex_lock(&chip->lock);
+	// toggle #CS pin to resume NAND device
+	nand_select_target(chip, 0);
+	ndelay(20);
+	nand_deselect_target(chip);
+
+	if (chip->suspend)
+		chip->suspended = 0;
+	else
+		pr_err("%s call for a chip which is not in suspended state\n",
+		       __func__);
+	mutex_unlock(&chip->lock);
+}
+
 /*
- * Macronix AC series support using SET/GET_FEATURES to change
+ * Macronix AC and AD series support using SET/GET_FEATURES to change
  * Block Protection and Unprotection.
  *
  * MTD call-back function replacement by manufacturer postponed
@@ -163,6 +227,18 @@ static void macronix_nand_post_init(struct nand_chip *chip)
 		}
 	}
 
+	for (i = 0; i < ARRAY_SIZE(nand_power_down); i++) {
+		if (!strcmp(nand_power_down[i], chip->parameters.model)) {
+			blockprotected = 1;
+			break;
+		}
+	}
+
+	if (i < ARRAY_SIZE(nand_power_down)) {
+		mtd->_suspend = mxic_nand_suspend;
+		mtd->_resume = mxic_nand_resume;
+	}
+
 	if (blockprotected && chip->parameters.supports_set_get_features) {
 		bitmap_set(chip->parameters.set_feature_list,
 			   ONFI_FEATURE_ADDR_MXIC_PROTECTION, 1);
-- 
1.9.1