mtd: nand: pxa3xx: Add multiple chunk write support

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=535cb57a4da0378b8a28d415249d501a4fa99ddf
Commit:     535cb57a4da0378b8a28d415249d501a4fa99ddf
Parent:     70ed85232a93af5253bff4802ef4ead1e83faa5f
Author:     Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
AuthorDate: Thu Nov 14 18:25:38 2013 -0300
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Fri Jan 3 11:22:17 2014 -0800

    mtd: nand: pxa3xx: Add multiple chunk write support
    
    This commit adds write support for large pages (4 KiB, 8 KiB).
    Such support is implemented by issuing a multiple command sequence,
    transfering a set of 2 KiB chunks per transaction.
    
    The splitted command sequence requires to send the SEQIN command
    independently of the PAGEPROG command and therefore it's set as
    an execution command.
    
    Since PAGEPROG enables ECC, each 2 KiB chunk of data is written
    together with ECC code at a controller-fixed location within
    the flash page.
    
    Currently, only devices with a 4 KiB page size has been tested.
    
    Signed-off-by: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
    Tested-by: Daniel Mack <zonque at gmail.com>
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 drivers/mtd/nand/pxa3xx_nand.c | 81 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 73 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
index 72dce45..ce3449c 100644
--- a/drivers/mtd/nand/pxa3xx_nand.c
+++ b/drivers/mtd/nand/pxa3xx_nand.c
@@ -756,6 +756,20 @@ static int prepare_set_command(struct pxa3xx_nand_info *info, int command,
 
 		info->buf_start = column;
 		set_command_address(info, mtd->writesize, 0, page_addr);
+
+		/*
+		 * Multiple page programming needs to execute the initial
+		 * SEQIN command that sets the page address.
+		 */
+		if (mtd->writesize > PAGE_CHUNK_SIZE) {
+			info->ndcb0 |= NDCB0_CMD_TYPE(0x1)
+				| NDCB0_EXT_CMD_TYPE(ext_cmd_type)
+				| addr_cycle
+				| command;
+			/* No data transfer in this case */
+			info->data_size = 0;
+			exec_cmd = 1;
+		}
 		break;
 
 	case NAND_CMD_PAGEPROG:
@@ -765,13 +779,40 @@ static int prepare_set_command(struct pxa3xx_nand_info *info, int command,
 			break;
 		}
 
-		info->ndcb0 |= NDCB0_CMD_TYPE(0x1)
-				| NDCB0_AUTO_RS
-				| NDCB0_ST_ROW_EN
-				| NDCB0_DBC
-				| (NAND_CMD_PAGEPROG << 8)
-				| NAND_CMD_SEQIN
-				| addr_cycle;
+		/* Second command setting for large pages */
+		if (mtd->writesize > PAGE_CHUNK_SIZE) {
+			/*
+			 * Multiple page write uses the 'extended command'
+			 * field. This can be used to issue a command dispatch
+			 * or a naked-write depending on the current stage.
+			 */
+			info->ndcb0 |= NDCB0_CMD_TYPE(0x1)
+					| NDCB0_LEN_OVRD
+					| NDCB0_EXT_CMD_TYPE(ext_cmd_type);
+			info->ndcb3 = info->chunk_size +
+				      info->oob_size;
+
+			/*
+			 * This is the command dispatch that completes a chunked
+			 * page program operation.
+			 */
+			if (info->data_size == 0) {
+				info->ndcb0 = NDCB0_CMD_TYPE(0x1)
+					| NDCB0_EXT_CMD_TYPE(ext_cmd_type)
+					| command;
+				info->ndcb1 = 0;
+				info->ndcb2 = 0;
+				info->ndcb3 = 0;
+			}
+		} else {
+			info->ndcb0 |= NDCB0_CMD_TYPE(0x1)
+					| NDCB0_AUTO_RS
+					| NDCB0_ST_ROW_EN
+					| NDCB0_DBC
+					| (NAND_CMD_PAGEPROG << 8)
+					| NAND_CMD_SEQIN
+					| addr_cycle;
+		}
 		break;
 
 	case NAND_CMD_PARAM:
@@ -915,8 +956,15 @@ static void armada370_nand_cmdfunc(struct mtd_info *mtd,
 	case NAND_CMD_READOOB:
 		ext_cmd_type = EXT_CMD_TYPE_MONO;
 		break;
+	case NAND_CMD_SEQIN:
+		ext_cmd_type = EXT_CMD_TYPE_DISPATCH;
+		break;
+	case NAND_CMD_PAGEPROG:
+		ext_cmd_type = EXT_CMD_TYPE_NAKED_RW;
+		break;
 	default:
 		ext_cmd_type = 0;
+		break;
 	}
 
 	prepare_start_command(info, command);
@@ -954,7 +1002,16 @@ static void armada370_nand_cmdfunc(struct mtd_info *mtd,
 		}
 
 		/* Check if the sequence is complete */
-		if (info->data_size == 0)
+		if (info->data_size == 0 && command != NAND_CMD_PAGEPROG)
+			break;
+
+		/*
+		 * After a splitted program command sequence has issued
+		 * the command dispatch, the command sequence is complete.
+		 */
+		if (info->data_size == 0 &&
+		    command == NAND_CMD_PAGEPROG &&
+		    ext_cmd_type == EXT_CMD_TYPE_DISPATCH)
 			break;
 
 		if (command == NAND_CMD_READ0 || command == NAND_CMD_READOOB) {
@@ -963,6 +1020,14 @@ static void armada370_nand_cmdfunc(struct mtd_info *mtd,
 				ext_cmd_type = EXT_CMD_TYPE_LAST_RW;
 			else
 				ext_cmd_type = EXT_CMD_TYPE_NAKED_RW;
+
+		/*
+		 * If a splitted program command has no more data to transfer,
+		 * the command dispatch must be issued to complete.
+		 */
+		} else if (command == NAND_CMD_PAGEPROG &&
+			   info->data_size == 0) {
+				ext_cmd_type = EXT_CMD_TYPE_DISPATCH;
 		}
 	} while (1);