mvebu: backport an upstream NAND flash driver fix

Signed-off-by: Felix Fietkau <[email protected]>

target/linux/mvebu/patches-4.4/010-mtd-nand-pxa3xx_nand-add-support-for-partial-chunks.patch

@@ -0,0 +1,428 @@
+From: Thomas Petazzoni <[email protected]>
+Date: Wed, 10 Feb 2016 14:54:21 +0100
+Subject: [PATCH] mtd: nand: pxa3xx_nand: add support for partial chunks
+
+This commit is needed to properly support the 8-bits ECC configuration
+with 4KB pages.
+
+When pages larger than 2 KB are used on platforms using the PXA3xx
+NAND controller, the reading/programming operations need to be split
+in chunks of 2 KBs or less because the controller FIFO is limited to
+about 2 KB (i.e a bit more than 2 KB to accommodate OOB data). Due to
+this requirement, the data layout on NAND is a bit strange, with ECC
+interleaved with data, at the end of each chunk.
+
+When a 4-bits ECC configuration is used with 4 KB pages, the physical
+data layout on the NAND looks like this:
+
+| 2048 data | 32 spare | 30 ECC | 2048 data | 32 spare | 30 ECC |
+
+So the data chunks have an equal size, 2080 bytes for each chunk,
+which the driver supports properly.
+
+When a 8-bits ECC configuration is used with 4KB pages, the physical
+data layout on the NAND looks like this:
+
+| 1024 data | 30 ECC | 1024 data | 30 ECC | 1024 data | 30 ECC | 1024 data | 30 ECC | 64 spare | 30 ECC |
+
+So, the spare area is stored in its own chunk, which has a different
+size than the other chunks. Since OOB is not used by UBIFS, the initial
+implementation of the driver has chosen to not support reading this
+additional "spare" chunk of data.
+
+Unfortunately, Marvell has chosen to store the BBT signature in the
+OOB area. Therefore, if the driver doesn't read this spare area, Linux
+has no way of finding the BBT. It thinks there is no BBT, and rewrites
+one, which U-Boot does not recognize, causing compatibility problems
+between the bootloader and the kernel in terms of NAND usage.
+
+To fix this, this commit implements the support for reading a partial
+last chunk. This support is currently only useful for the case of 8
+bits ECC with 4 KB pages, but it will be useful in the future to
+enable other configurations such as 12 bits and 16 bits ECC with 4 KB
+pages, or 8 bits ECC with 8 KB pages, etc. All those configurations
+have a "last" chunk that doesn't have the same size as the other
+chunks.
+
+In order to implement reading of the last chunk, this commit:
+
+ - Adds a number of new fields to the pxa3xx_nand_info to describe how
+   many full chunks and how many chunks we have, the size of full
+   chunks and partial chunks, both in terms of data area and spare
+   area.
+
+ - Fills in the step_chunk_size and step_spare_size variables to
+   describe how much data and spare should be read/written for the
+   current read/program step.
+
+ - Reworks the state machine to accommodate doing the additional read
+   or program step when a last partial chunk is used.
+
+This commit has been tested on a Marvell Armada 398 DB board, with a
+4KB page NAND, tested in both 4 bits ECC and 8 bits ECC
+configurations. Robert Jarzmik has tested on some PXA platforms.
+
+Signed-off-by: Thomas Petazzoni <[email protected]>
+Tested-by: Robert Jarzmik <[email protected]>
+Acked-by: Ezequiel Garcia <[email protected]>
+Signed-off-by: Brian Norris <[email protected]>
+---
+
+--- a/drivers/mtd/nand/pxa3xx_nand.c
++++ b/drivers/mtd/nand/pxa3xx_nand.c
+@@ -228,15 +228,44 @@ struct pxa3xx_nand_info {
+ 	int			use_spare;	/* use spare ? */
+ 	int			need_wait;
+ 
+-	unsigned int		data_size;	/* data to be read from FIFO */
+-	unsigned int		chunk_size;	/* split commands chunk size */
+-	unsigned int		oob_size;
++	/* Amount of real data per full chunk */
++	unsigned int		chunk_size;
++
++	/* Amount of spare data per full chunk */
+ 	unsigned int		spare_size;
++
++	/* Number of full chunks (i.e chunk_size + spare_size) */
++	unsigned int            nfullchunks;
++
++	/*
++	 * Total number of chunks. If equal to nfullchunks, then there
++	 * are only full chunks. Otherwise, there is one last chunk of
++	 * size (last_chunk_size + last_spare_size)
++	 */
++	unsigned int            ntotalchunks;
++
++	/* Amount of real data in the last chunk */
++	unsigned int		last_chunk_size;
++
++	/* Amount of spare data in the last chunk */
++	unsigned int		last_spare_size;
++
+ 	unsigned int		ecc_size;
+ 	unsigned int		ecc_err_cnt;
+ 	unsigned int		max_bitflips;
+ 	int 			retcode;
+ 
++	/*
++	 * Variables only valid during command
++	 * execution. step_chunk_size and step_spare_size is the
++	 * amount of real data and spare data in the current
++	 * chunk. cur_chunk is the current chunk being
++	 * read/programmed.
++	 */
++	unsigned int		step_chunk_size;
++	unsigned int		step_spare_size;
++	unsigned int            cur_chunk;
++
+ 	/* cached register value */
+ 	uint32_t		reg_ndcr;
+ 	uint32_t		ndtr0cs0;
+@@ -531,25 +560,6 @@ static int pxa3xx_nand_init(struct pxa3x
+ 	return 0;
+ }
+ 
+-/*
+- * Set the data and OOB size, depending on the selected
+- * spare and ECC configuration.
+- * Only applicable to READ0, READOOB and PAGEPROG commands.
+- */
+-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 = mtd->writesize;
+-	if (!oob_enable)
+-		return;
+-
+-	info->oob_size = info->spare_size;
+-	if (!info->use_ecc)
+-		info->oob_size += info->ecc_size;
+-}
+-
+ /**
+  * NOTE: it is a must to set ND_RUN firstly, then write
+  * command buffer, otherwise, it does not work.
+@@ -665,28 +675,28 @@ static void drain_fifo(struct pxa3xx_nan
+ 
+ static void handle_data_pio(struct pxa3xx_nand_info *info)
+ {
+-	unsigned int do_bytes = min(info->data_size, info->chunk_size);
+-
+ 	switch (info->state) {
+ 	case STATE_PIO_WRITING:
+-		writesl(info->mmio_base + NDDB,
+-			info->data_buff + info->data_buff_pos,
+-			DIV_ROUND_UP(do_bytes, 4));
++		if (info->step_chunk_size)
++			writesl(info->mmio_base + NDDB,
++				info->data_buff + info->data_buff_pos,
++				DIV_ROUND_UP(info->step_chunk_size, 4));
+ 
+-		if (info->oob_size > 0)
++		if (info->step_spare_size)
+ 			writesl(info->mmio_base + NDDB,
+ 				info->oob_buff + info->oob_buff_pos,
+-				DIV_ROUND_UP(info->oob_size, 4));
++				DIV_ROUND_UP(info->step_spare_size, 4));
+ 		break;
+ 	case STATE_PIO_READING:
+-		drain_fifo(info,
+-			   info->data_buff + info->data_buff_pos,
+-			   DIV_ROUND_UP(do_bytes, 4));
++		if (info->step_chunk_size)
++			drain_fifo(info,
++				   info->data_buff + info->data_buff_pos,
++				   DIV_ROUND_UP(info->step_chunk_size, 4));
+ 
+-		if (info->oob_size > 0)
++		if (info->step_spare_size)
+ 			drain_fifo(info,
+ 				   info->oob_buff + info->oob_buff_pos,
+-				   DIV_ROUND_UP(info->oob_size, 4));
++				   DIV_ROUND_UP(info->step_spare_size, 4));
+ 		break;
+ 	default:
+ 		dev_err(&info->pdev->dev, "%s: invalid state %d\n", __func__,
+@@ -695,9 +705,8 @@ static void handle_data_pio(struct pxa3x
+ 	}
+ 
+ 	/* 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;
++	info->data_buff_pos += info->step_chunk_size;
++	info->oob_buff_pos += info->step_spare_size;
+ }
+ 
+ static void pxa3xx_nand_data_dma_irq(void *data)
+@@ -738,8 +747,9 @@ static void start_data_dma(struct pxa3xx
+ 				info->state);
+ 		BUG();
+ 	}
+-	info->sg.length = info->data_size +
+-		(info->oob_size ? info->spare_size + info->ecc_size : 0);
++	info->sg.length = info->chunk_size;
++	if (info->use_spare)
++		info->sg.length += info->spare_size + info->ecc_size;
+ 	dma_map_sg(info->dma_chan->device->dev, &info->sg, 1, info->dma_dir);
+ 
+ 	tx = dmaengine_prep_slave_sg(info->dma_chan, &info->sg, 1, direction,
+@@ -900,9 +910,11 @@ static void prepare_start_command(struct
+ 	/* reset data and oob column point to handle data */
+ 	info->buf_start		= 0;
+ 	info->buf_count		= 0;
+-	info->oob_size		= 0;
+ 	info->data_buff_pos	= 0;
+ 	info->oob_buff_pos	= 0;
++	info->step_chunk_size   = 0;
++	info->step_spare_size   = 0;
++	info->cur_chunk         = 0;
+ 	info->use_ecc		= 0;
+ 	info->use_spare		= 1;
+ 	info->retcode		= ERR_NONE;
+@@ -914,8 +926,6 @@ static void prepare_start_command(struct
+ 	case NAND_CMD_READ0:
+ 	case NAND_CMD_PAGEPROG:
+ 		info->use_ecc = 1;
+-	case NAND_CMD_READOOB:
+-		pxa3xx_set_datasize(info, mtd);
+ 		break;
+ 	case NAND_CMD_PARAM:
+ 		info->use_spare = 0;
+@@ -974,6 +984,14 @@ static int prepare_set_command(struct px
+ 		if (command == NAND_CMD_READOOB)
+ 			info->buf_start += mtd->writesize;
+ 
++		if (info->cur_chunk < info->nfullchunks) {
++			info->step_chunk_size = info->chunk_size;
++			info->step_spare_size = info->spare_size;
++		} else {
++			info->step_chunk_size = info->last_chunk_size;
++			info->step_spare_size = info->last_spare_size;
++		}
++
+ 		/*
+ 		 * Multiple page read needs an 'extended command type' field,
+ 		 * which is either naked-read or last-read according to the
+@@ -985,8 +1003,8 @@ static int prepare_set_command(struct px
+ 			info->ndcb0 |= NDCB0_DBC | (NAND_CMD_READSTART << 8)
+ 					| NDCB0_LEN_OVRD
+ 					| NDCB0_EXT_CMD_TYPE(ext_cmd_type);
+-			info->ndcb3 = info->chunk_size +
+-				      info->oob_size;
++			info->ndcb3 = info->step_chunk_size +
++				info->step_spare_size;
+ 		}
+ 
+ 		set_command_address(info, mtd->writesize, column, page_addr);
+@@ -1006,8 +1024,6 @@ static int prepare_set_command(struct px
+ 				| NDCB0_EXT_CMD_TYPE(ext_cmd_type)
+ 				| addr_cycle
+ 				| command;
+-			/* No data transfer in this case */
+-			info->data_size = 0;
+ 			exec_cmd = 1;
+ 		}
+ 		break;
+@@ -1019,6 +1035,14 @@ static int prepare_set_command(struct px
+ 			break;
+ 		}
+ 
++		if (info->cur_chunk < info->nfullchunks) {
++			info->step_chunk_size = info->chunk_size;
++			info->step_spare_size = info->spare_size;
++		} else {
++			info->step_chunk_size = info->last_chunk_size;
++			info->step_spare_size = info->last_spare_size;
++		}
++
+ 		/* Second command setting for large pages */
+ 		if (mtd->writesize > PAGE_CHUNK_SIZE) {
+ 			/*
+@@ -1029,14 +1053,14 @@ static int prepare_set_command(struct px
+ 			info->ndcb0 |= NDCB0_CMD_TYPE(0x1)
+ 					| NDCB0_LEN_OVRD
+ 					| NDCB0_EXT_CMD_TYPE(ext_cmd_type);
+-			info->ndcb3 = info->chunk_size +
+-				      info->oob_size;
++			info->ndcb3 = info->step_chunk_size +
++				      info->step_spare_size;
+ 
+ 			/*
+ 			 * This is the command dispatch that completes a chunked
+ 			 * page program operation.
+ 			 */
+-			if (info->data_size == 0) {
++			if (info->cur_chunk == info->ntotalchunks) {
+ 				info->ndcb0 = NDCB0_CMD_TYPE(0x1)
+ 					| NDCB0_EXT_CMD_TYPE(ext_cmd_type)
+ 					| command;
+@@ -1063,7 +1087,7 @@ static int prepare_set_command(struct px
+ 				| command;
+ 		info->ndcb1 = (column & 0xFF);
+ 		info->ndcb3 = INIT_BUFFER_SIZE;
+-		info->data_size = INIT_BUFFER_SIZE;
++		info->step_chunk_size = INIT_BUFFER_SIZE;
+ 		break;
+ 
+ 	case NAND_CMD_READID:
+@@ -1073,7 +1097,7 @@ static int prepare_set_command(struct px
+ 				| command;
+ 		info->ndcb1 = (column & 0xFF);
+ 
+-		info->data_size = 8;
++		info->step_chunk_size = 8;
+ 		break;
+ 	case NAND_CMD_STATUS:
+ 		info->buf_count = 1;
+@@ -1081,7 +1105,7 @@ static int prepare_set_command(struct px
+ 				| NDCB0_ADDR_CYC(1)
+ 				| command;
+ 
+-		info->data_size = 8;
++		info->step_chunk_size = 8;
+ 		break;
+ 
+ 	case NAND_CMD_ERASE1:
+@@ -1220,6 +1244,7 @@ static void nand_cmdfunc_extended(struct
+ 	init_completion(&info->dev_ready);
+ 	do {
+ 		info->state = STATE_PREPARED;
++
+ 		exec_cmd = prepare_set_command(info, command, ext_cmd_type,
+ 					       column, page_addr);
+ 		if (!exec_cmd) {
+@@ -1239,22 +1264,30 @@ static void nand_cmdfunc_extended(struct
+ 			break;
+ 		}
+ 
++		/* Only a few commands need several steps */
++		if (command != NAND_CMD_PAGEPROG &&
++		    command != NAND_CMD_READ0    &&
++		    command != NAND_CMD_READOOB)
++			break;
++
++		info->cur_chunk++;
++
+ 		/* Check if the sequence is complete */
+-		if (info->data_size == 0 && command != NAND_CMD_PAGEPROG)
++		if (info->cur_chunk == info->ntotalchunks && 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 &&
++		if (info->cur_chunk == (info->ntotalchunks + 1) &&
+ 		    command == NAND_CMD_PAGEPROG &&
+ 		    ext_cmd_type == EXT_CMD_TYPE_DISPATCH)
+ 			break;
+ 
+ 		if (command == NAND_CMD_READ0 || command == NAND_CMD_READOOB) {
+ 			/* Last read: issue a 'last naked read' */
+-			if (info->data_size == info->chunk_size)
++			if (info->cur_chunk == info->ntotalchunks - 1)
+ 				ext_cmd_type = EXT_CMD_TYPE_LAST_RW;
+ 			else
+ 				ext_cmd_type = EXT_CMD_TYPE_NAKED_RW;
+@@ -1264,7 +1297,7 @@ static void nand_cmdfunc_extended(struct
+ 		 * the command dispatch must be issued to complete.
+ 		 */
+ 		} else if (command == NAND_CMD_PAGEPROG &&
+-			   info->data_size == 0) {
++			   info->cur_chunk == info->ntotalchunks) {
+ 				ext_cmd_type = EXT_CMD_TYPE_DISPATCH;
+ 		}
+ 	} while (1);
+@@ -1514,6 +1547,8 @@ static int pxa_ecc_init(struct pxa3xx_na
+ 			int strength, int ecc_stepsize, int page_size)
+ {
+ 	if (strength == 1 && ecc_stepsize == 512 && page_size == 2048) {
++		info->nfullchunks = 1;
++		info->ntotalchunks = 1;
+ 		info->chunk_size = 2048;
+ 		info->spare_size = 40;
+ 		info->ecc_size = 24;
+@@ -1522,6 +1557,8 @@ static int pxa_ecc_init(struct pxa3xx_na
+ 		ecc->strength = 1;
+ 
+ 	} else if (strength == 1 && ecc_stepsize == 512 && page_size == 512) {
++		info->nfullchunks = 1;
++		info->ntotalchunks = 1;
+ 		info->chunk_size = 512;
+ 		info->spare_size = 8;
+ 		info->ecc_size = 8;
+@@ -1535,6 +1572,8 @@ static int pxa_ecc_init(struct pxa3xx_na
+ 	 */
+ 	} else if (strength == 4 && ecc_stepsize == 512 && page_size == 2048) {
+ 		info->ecc_bch = 1;
++		info->nfullchunks = 1;
++		info->ntotalchunks = 1;
+ 		info->chunk_size = 2048;
+ 		info->spare_size = 32;
+ 		info->ecc_size = 32;
+@@ -1545,6 +1584,8 @@ static int pxa_ecc_init(struct pxa3xx_na
+ 
+ 	} else if (strength == 4 && ecc_stepsize == 512 && page_size == 4096) {
+ 		info->ecc_bch = 1;
++		info->nfullchunks = 2;
++		info->ntotalchunks = 2;
+ 		info->chunk_size = 2048;
+ 		info->spare_size = 32;
+ 		info->ecc_size = 32;
+@@ -1559,8 +1600,12 @@ static int pxa_ecc_init(struct pxa3xx_na
+ 	 */
+ 	} else if (strength == 8 && ecc_stepsize == 512 && page_size == 4096) {
+ 		info->ecc_bch = 1;
++		info->nfullchunks = 4;
++		info->ntotalchunks = 5;
+ 		info->chunk_size = 1024;
+ 		info->spare_size = 0;
++		info->last_chunk_size = 0;
++		info->last_spare_size = 64;
+ 		info->ecc_size = 32;
+ 		ecc->mode = NAND_ECC_HW;
+ 		ecc->size = info->chunk_size;