mtd: nand: pxa3xx: Add a read/write buffers markers

In preparation to support multiple (aka chunked, aka splitted)
page I/O, this commit adds 'data_buff_pos' and 'oob_buff_pos' fields
to keep track of where the next read (or write) should be done.

This will allow multiple calls to handle_data_pio() to continue
the read (or write) operation.
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/pxa3xx_nand.c

@@ -176,6 +176,8 @@ struct pxa3xx_nand_info {
 	unsigned int 		buf_start;
 	unsigned int		buf_count;
 	unsigned int		buf_size;
+	unsigned int		data_buff_pos;
+	unsigned int		oob_buff_pos;
 
 	/* DMA information */
 	int			drcmr_dat;
@@ -334,11 +336,12 @@ static void pxa3xx_nand_set_timing(struct pxa3xx_nand_host *host,
  * spare and ECC configuration.
  * Only applicable to READ0, READOOB and PAGEPROG commands.
  */
-static void pxa3xx_set_datasize(struct pxa3xx_nand_info *info)
+static void pxa3xx_set_datasize(struct pxa3xx_nand_info *info,
+				struct mtd_info *mtd)
 {
 	int oob_enable = info->reg_ndcr & NDCR_SPARE_EN;
 
-	info->data_size = info->fifo_size;
+	info->data_size = mtd->writesize;
 	if (!oob_enable)
 		return;
 
@@ -426,19 +429,27 @@ static void disable_int(struct pxa3xx_nand_info *info, uint32_t int_mask)
 
 static void handle_data_pio(struct pxa3xx_nand_info *info)
 {
+	unsigned int do_bytes = min(info->data_size, info->fifo_size);
+
 	switch (info->state) {
 	case STATE_PIO_WRITING:
-		__raw_writesl(info->mmio_base + NDDB, info->data_buff,
-				DIV_ROUND_UP(info->data_size, 4));
+		__raw_writesl(info->mmio_base + NDDB,
+			      info->data_buff + info->data_buff_pos,
+			      DIV_ROUND_UP(do_bytes, 4));
+
 		if (info->oob_size > 0)
-			__raw_writesl(info->mmio_base + NDDB, info->oob_buff,
+			__raw_writesl(info->mmio_base + NDDB,
+				      info->oob_buff + info->oob_buff_pos,
 				      DIV_ROUND_UP(info->oob_size, 4));
 		break;
 	case STATE_PIO_READING:
-		__raw_readsl(info->mmio_base + NDDB, info->data_buff,
-				DIV_ROUND_UP(info->data_size, 4));
+		__raw_readsl(info->mmio_base + NDDB,
+			     info->data_buff + info->data_buff_pos,
+			     DIV_ROUND_UP(do_bytes, 4));
+
 		if (info->oob_size > 0)
-			__raw_readsl(info->mmio_base + NDDB, info->oob_buff,
+			__raw_readsl(info->mmio_base + NDDB,
+				     info->oob_buff + info->oob_buff_pos,
 				     DIV_ROUND_UP(info->oob_size, 4));
 		break;
 	default:
@@ -446,6 +457,11 @@ static void handle_data_pio(struct pxa3xx_nand_info *info)
 				info->state);
 		BUG();
 	}
+
+	/* Update buffer pointers for multi-page read/write */
+	info->data_buff_pos += do_bytes;
+	info->oob_buff_pos += info->oob_size;
+	info->data_size -= do_bytes;
 }
 
 #ifdef ARCH_HAS_DMA
@@ -612,6 +628,8 @@ static void prepare_start_command(struct pxa3xx_nand_info *info, int command)
 	info->buf_start		= 0;
 	info->buf_count		= 0;
 	info->oob_size		= 0;
+	info->data_buff_pos	= 0;
+	info->oob_buff_pos	= 0;
 	info->use_ecc		= 0;
 	info->use_spare		= 1;
 	info->retcode		= ERR_NONE;
@@ -622,7 +640,7 @@ static void prepare_start_command(struct pxa3xx_nand_info *info, int command)
 	case NAND_CMD_PAGEPROG:
 		info->use_ecc = 1;
 	case NAND_CMD_READOOB:
-		pxa3xx_set_datasize(info);
+		pxa3xx_set_datasize(info, mtd);
 		break;
 	case NAND_CMD_PARAM:
 		info->use_spare = 0;