[PATCH v2] mtd: OneNAND: Cache Program support on 4KiB pagesize

[Kyungmin Park <kmpark@infradead.org>]

Hi Roman,

How about this patch? Just remove the pseudo command and use real command.
As In case of 2KiB pagesize, it uses the write-while-program so not much write improvement.

Give your opinions.

Thank you,
Kyungmin Park

---
diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index 6b3a875..586ba4b 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -1845,7 +1845,7 @@ static int onenand_write_ops_nolock(struct mtd_info *mtd, loff_t to,
 	const u_char *buf = ops->datbuf;
 	const u_char *oob = ops->oobbuf;
 	u_char *oobbuf;
-	int ret = 0;
+	int ret = 0, cmd;
 
 	DEBUG(MTD_DEBUG_LEVEL3, "%s: to = 0x%08x, len = %i\n",
 		__func__, (unsigned int) to, (int) len);
@@ -1954,7 +1954,26 @@ static int onenand_write_ops_nolock(struct mtd_info *mtd, loff_t to,
 			ONENAND_SET_NEXT_BUFFERRAM(this);
 		}
 
-		this->command(mtd, ONENAND_CMD_PROG, to, mtd->writesize);
+		this->ongoing = 0;
+
+		/* Default write command */
+		cmd = ONENAND_CMD_PROG;
+
+		/*
+		 * Cache Program support
+		 * Exclude 1st OTP and OTP blocks
+		 */
+		if (ONENAND_IS_CACHE_PROGRAM(this) &&
+		    likely(onenand_block(this, to) != 0) &&
+		    ONENAND_IS_4KB_PAGE(this)) {
+
+			if ((written + thislen) < len) {
+				cmd = ONENAND_CMD_2X_CACHE_PROG;
+				this->ongoing = 1;
+			}
+		}
+
+		this->command(mtd, cmd, to, mtd->writesize);
 
 		/*
 		 * 2 PLANE, MLC, and Flex-OneNAND wait here
@@ -3380,6 +3399,8 @@ static void onenand_check_features(struct mtd_info *mtd)
 		else if (numbufs == 1)
 			this->options |= ONENAND_HAS_4KB_PAGE;
 
+		this->options |= ONENAND_HAS_CACHE_PROGRAM;
+
 	case ONENAND_DEVICE_DENSITY_2Gb:
 		/* 2Gb DDP does not have 2 plane */
 		if (!ONENAND_IS_DDP(this))
@@ -3415,6 +3436,8 @@ static void onenand_check_features(struct mtd_info *mtd)
 		printk(KERN_DEBUG "Chip has 2 plane\n");
 	if (this->options & ONENAND_HAS_4KB_PAGE)
 		printk(KERN_DEBUG "Chip has 4KiB pagesize\n");
+	if (this->options & ONENAND_HAS_CACHE_PROGRAM)
+		printk(KERN_DEBUG "Chip has cache program feature\n");
 }
 
 /**
diff --git a/include/linux/mtd/onenand.h b/include/linux/mtd/onenand.h
index 0c8815b..3bb1a91 100644
--- a/include/linux/mtd/onenand.h
+++ b/include/linux/mtd/onenand.h
@@ -137,6 +137,14 @@ struct onenand_chip {
 	void			*bbm;
 
 	void			*priv;
+
+	/*
+	 * Shows that the current operation is composed
+	 * of sequence of commands. For example, cache program.
+	 * Such command status OnGo bit is checked at the end of
+	 * sequence.
+	 */
+	unsigned int            ongoing;
 };
 
 /*
@@ -171,6 +179,9 @@ struct onenand_chip {
 #define ONENAND_IS_2PLANE(this)			(0)
 #endif
 
+#define ONENAND_IS_CACHE_PROGRAM(this)					\
+	(this->options & ONENAND_HAS_CACHE_PROGRAM)
+
 /* Check byte access in OneNAND */
 #define ONENAND_CHECK_BYTE_ACCESS(addr)		(addr & 0x1)
 
@@ -181,6 +192,7 @@ struct onenand_chip {
 #define ONENAND_HAS_UNLOCK_ALL		(0x0002)
 #define ONENAND_HAS_2PLANE		(0x0004)
 #define ONENAND_HAS_4KB_PAGE		(0x0008)
+#define ONENAND_HAS_CACHE_PROGRAM	(0x0010)
 #define ONENAND_SKIP_UNLOCK_CHECK	(0x0100)
 #define ONENAND_PAGEBUF_ALLOC		(0x1000)
 #define ONENAND_OOBBUF_ALLOC		(0x2000)