mtd: OneNAND: multiblock erase support

Add support for multiblock erase command. OneNANDs (excluding Flex-OneNAND)
are capable of simultaneous erase of up to 64 eraseblocks which is much faster.

This changes the erase requests for regions covering multiple eraseblocks
to be performed using multiblock erase.

Signed-off-by: Mika Korhonen <[e-mail]>
Reviewed-by: Adrian Hunter <[e-mail]>
Signed-off-by: Artem Bityutskiy <[e-mail]>
Signed-off-by: David Woodhouse <[e-mail]>

drivers/mtd/onenand/omap2.c

···
 	unsigned long timeout;
 	u32 syscfg;
 
-	if (state == FL_RESETING) {
-		int i;
+	if (state == FL_RESETING || state == FL_PREPARING_ERASE ||
+	    state == FL_VERIFYING_ERASE) {
+		int i = 21;
+		unsigned int intr_flags = ONENAND_INT_MASTER;
 
-		for (i = 0; i < 20; i++) {
+		switch (state) {
+		case FL_RESETING:
+			intr_flags |= ONENAND_INT_RESET;
+			break;
+		case FL_PREPARING_ERASE:
+			intr_flags |= ONENAND_INT_ERASE;
+			break;
+		case FL_VERIFYING_ERASE:
+			i = 101;
+			break;
+		}
+
+		while (--i) {
 			udelay(1);
 			intr = read_reg(c, ONENAND_REG_INTERRUPT);
 			if (intr & ONENAND_INT_MASTER)
···
 			wait_err("controller error", state, ctrl, intr);
 			return -EIO;
 		}
-		if (!(intr & ONENAND_INT_RESET)) {
+		if ((intr & intr_flags) != intr_flags) {
 			wait_err("timeout", state, ctrl, intr);
 			return -EIO;
 		}

drivers/mtd/onenand/onenand_base.c

···
 
 #include <asm/io.h>
 
+/*
+ * Multiblock erase if number of blocks to erase is 2 or more.
+ * Maximum number of blocks for simultaneous erase is 64.
+ */
+#define MB_ERASE_MIN_BLK_COUNT 2
+#define MB_ERASE_MAX_BLK_COUNT 64
+
 /* Default Flex-OneNAND boundary and lock respectively */
 static int flex_bdry[MAX_DIES * 2] = { -1, 0, -1, 0 };
 
···
 		break;
 
 	case ONENAND_CMD_ERASE:
+	case ONENAND_CMD_MULTIBLOCK_ERASE:
+	case ONENAND_CMD_ERASE_VERIFY:
 	case ONENAND_CMD_BUFFERRAM:
 	case ONENAND_CMD_OTP_ACCESS:
 		block = onenand_block(this, addr);
···
 		if (interrupt & flags)
 			break;
 
-		if (state != FL_READING)
+		if (state != FL_READING && state != FL_PREPARING_ERASE)
 			cond_resched();
 	}
 	/* To get correct interrupt status in timeout case */
···
 	} else if (state == FL_READING) {
 		printk(KERN_ERR "%s: read timeout! ctrl=0x%04x intr=0x%04x\n",
 			__func__, ctrl, interrupt);
+		return -EIO;
+	}
+
+	if (state == FL_PREPARING_ERASE && !(interrupt & ONENAND_INT_ERASE)) {
+		printk(KERN_ERR "%s: mb erase timeout! ctrl=0x%04x intr=0x%04x\n",
+		       __func__, ctrl, interrupt);
+		return -EIO;
+	}
+
+	if (!(interrupt & ONENAND_INT_MASTER)) {
+		printk(KERN_ERR "%s: timeout! ctrl=0x%04x intr=0x%04x\n",
+		       __func__, ctrl, interrupt);
 		return -EIO;
 	}
 
···
 	return bbm->isbad_bbt(mtd, ofs, allowbbt);
 }
 
+
+static int onenand_multiblock_erase_verify(struct mtd_info *mtd,
+					   struct erase_info *instr)
+{
+	struct onenand_chip *this = mtd->priv;
+	loff_t addr = instr->addr;
+	int len = instr->len;
+	unsigned int block_size = (1 << this->erase_shift);
+	int ret = 0;
+
+	while (len) {
+		this->command(mtd, ONENAND_CMD_ERASE_VERIFY, addr, block_size);
+		ret = this->wait(mtd, FL_VERIFYING_ERASE);
+		if (ret) {
+			printk(KERN_ERR "%s: Failed verify, block %d\n",
+			       __func__, onenand_block(this, addr));
+			instr->state = MTD_ERASE_FAILED;
+			instr->fail_addr = addr;
+			return -1;
+		}
+		len -= block_size;
+		addr += block_size;
+	}
+	return 0;
+}
+
+/**
+ * onenand_multiblock_erase - [Internal] erase block(s) using multiblock erase
+ * @param mtd		MTD device structure
+ * @param instr		erase instruction
+ * @param region	erase region
+ *
+ * Erase one or more blocks up to 64 block at a time
+ */
+static int onenand_multiblock_erase(struct mtd_info *mtd,
+				    struct erase_info *instr,
+				    unsigned int block_size)
+{
+	struct onenand_chip *this = mtd->priv;
+	loff_t addr = instr->addr;
+	int len = instr->len;
+	int eb_count = 0;
+	int ret = 0;
+	int bdry_block = 0;
+
+	instr->state = MTD_ERASING;
+
+	if (ONENAND_IS_DDP(this)) {
+		loff_t bdry_addr = this->chipsize >> 1;
+		if (addr < bdry_addr && (addr + len) > bdry_addr)
+			bdry_block = bdry_addr >> this->erase_shift;
+	}
+
+	/* Pre-check bbs */
+	while (len) {
+		/* Check if we have a bad block, we do not erase bad blocks */
+		if (onenand_block_isbad_nolock(mtd, addr, 0)) {
+			printk(KERN_WARNING "%s: attempt to erase a bad block "
+			       "at addr 0x%012llx\n",
+			       __func__, (unsigned long long) addr);
+			instr->state = MTD_ERASE_FAILED;
+			return -EIO;
+		}
+		len -= block_size;
+		addr += block_size;
+	}
+
+	len = instr->len;
+	addr = instr->addr;
+
+	/* loop over 64 eb batches */
+	while (len) {
+		struct erase_info verify_instr = *instr;
+		int max_eb_count = MB_ERASE_MAX_BLK_COUNT;
+
+		verify_instr.addr = addr;
+		verify_instr.len = 0;
+
+		/* do not cross chip boundary */
+		if (bdry_block) {
+			int this_block = (addr >> this->erase_shift);
+
+			if (this_block < bdry_block) {
+				max_eb_count = min(max_eb_count,
+						   (bdry_block - this_block));
+			}
+		}
+
+		eb_count = 0;
+
+		while (len > block_size && eb_count < (max_eb_count - 1)) {
+			this->command(mtd, ONENAND_CMD_MULTIBLOCK_ERASE,
+				      addr, block_size);
+			onenand_invalidate_bufferram(mtd, addr, block_size);
+
+			ret = this->wait(mtd, FL_PREPARING_ERASE);
+			if (ret) {
+				printk(KERN_ERR "%s: Failed multiblock erase, "
+				       "block %d\n", __func__,
+				       onenand_block(this, addr));
+				instr->state = MTD_ERASE_FAILED;
+				instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
+				return -EIO;
+			}
+
+			len -= block_size;
+			addr += block_size;
+			eb_count++;
+		}
+
+		/* last block of 64-eb series */
+		cond_resched();
+		this->command(mtd, ONENAND_CMD_ERASE, addr, block_size);
+		onenand_invalidate_bufferram(mtd, addr, block_size);
+
+		ret = this->wait(mtd, FL_ERASING);
+		/* Check if it is write protected */
+		if (ret) {
+			printk(KERN_ERR "%s: Failed erase, block %d\n",
+			       __func__, onenand_block(this, addr));
+			instr->state = MTD_ERASE_FAILED;
+			instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
+			return -EIO;
+		}
+
+		len -= block_size;
+		addr += block_size;
+		eb_count++;
+
+		/* verify */
+		verify_instr.len = eb_count * block_size;
+		if (onenand_multiblock_erase_verify(mtd, &verify_instr)) {
+			instr->state = verify_instr.state;
+			instr->fail_addr = verify_instr.fail_addr;
+			return -EIO;
+		}
+
+	}
+	return 0;
+}
+
+
 /**
  * onenand_block_by_block_erase - [Internal] erase block(s) using regular erase
  * @param mtd		MTD device structure
···
 	/* Grab the lock and see if the device is available */
 	onenand_get_device(mtd, FL_ERASING);
 
-	ret = onenand_block_by_block_erase(mtd, instr, region, block_size);
+	if (region || instr->len < MB_ERASE_MIN_BLK_COUNT * block_size) {
+		/* region is set for Flex-OneNAND (no mb erase) */
+		ret = onenand_block_by_block_erase(mtd, instr,
+						   region, block_size);
+	} else {
+		ret = onenand_multiblock_erase(mtd, instr, block_size);
+	}
 
 	/* Deselect and wake up anyone waiting on the device */
 	onenand_release_device(mtd);

include/linux/mtd/flashchip.h

···
 	/* These 2 come from nand_state_t, which has been unified here */
 	FL_READING,
 	FL_CACHEDPRG,
-	/* These 2 come from onenand_state_t, which has been unified here */
+	/* These 4 come from onenand_state_t, which has been unified here */
 	FL_RESETING,
 	FL_OTPING,
+	FL_PREPARING_ERASE,
+	FL_VERIFYING_ERASE,
 
 	FL_UNKNOWN
 } flstate_t;

include/linux/mtd/onenand_regs.h

···
 #define ONENAND_CMD_LOCK_TIGHT		(0x2C)
 #define ONENAND_CMD_UNLOCK_ALL		(0x27)
 #define ONENAND_CMD_ERASE		(0x94)
+#define ONENAND_CMD_MULTIBLOCK_ERASE	(0x95)
+#define ONENAND_CMD_ERASE_VERIFY	(0x71)
 #define ONENAND_CMD_RESET		(0xF0)
 #define ONENAND_CMD_OTP_ACCESS		(0x65)
 #define ONENAND_CMD_READID		(0x90)