[PATCH v2 1/6] mtd: spi-nor: Add parallel and stacked memories support

Michal Simek michal.simek at amd.com
Wed Oct 18 09:43:44 CEST 2023



On 10/17/23 05:31, Venkatesh Yadav Abbarapu wrote:
> From: Ashok Reddy Soma <ashok.reddy.soma at amd.com>
> 
> In parallel mode, the current implementation assumes that a maximum of
> two flashes are connected. The QSPI controller splits the data evenly
> between both the flashes so, both the flashes that are connected in
> parallel mode should be identical.
> During each operation SPI-NOR sets 0th bit for CS0 & 1st bit for CS1 in
> nor->flags.
> 
> In stacked mode the current implementation assumes that a maximum of two
> flashes are connected and both the flashes are of same make but can
> differ in sizes. So, except the sizes all other flash parameters of both
> the flashes are identical
> 
> Spi-nor will pass on the appropriate flash select flag to low level
> driver, and it will select pass all the data to that particular flash.
> 
> Write operation in parallel mode are performed in page size * 2 chunks as
> each write operation results in writing both the flashes. For doubling
> the address space each operation is performed at addr/2 flash offset,
> where addr is the address specified by the user.
> 
> Similarly for read and erase operations it will read from both flashes,
> so size and offset are divided by 2 and send to flash.
> 
> Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma at amd.com>
> Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu at amd.com>
> ---
>   drivers/mtd/spi/spi-nor-core.c | 280 +++++++++++++++++++++++++++++----
>   include/linux/mtd/spi-nor.h    |  13 ++
>   include/spi.h                  |  12 ++
>   3 files changed, 277 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
> index db20feb4da..b2e5494e78 100644
> --- a/drivers/mtd/spi/spi-nor-core.c
> +++ b/drivers/mtd/spi/spi-nor-core.c
> @@ -639,12 +639,17 @@ static u8 spi_nor_convert_3to4_erase(u8 opcode)
>   static void spi_nor_set_4byte_opcodes(struct spi_nor *nor,
>   				      const struct flash_info *info)
>   {
> +	bool shift = 0;
> +
> +	if (nor->flags & SNOR_F_HAS_PARALLEL)
> +		shift = 1;
> +
>   	/* Do some manufacturer fixups first */
>   	switch (JEDEC_MFR(info)) {
>   	case SNOR_MFR_SPANSION:
>   		/* No small sector erase for 4-byte command set */
>   		nor->erase_opcode = SPINOR_OP_SE;
> -		nor->mtd.erasesize = info->sector_size;
> +		nor->mtd.erasesize = info->sector_size << shift;
>   		break;
>   
>   	default:
> @@ -965,8 +970,8 @@ static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
>   static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
>   {
>   	struct spi_nor *nor = mtd_to_spi_nor(mtd);
> +	u32 addr, len, rem, offset;
>   	bool addr_known = false;
> -	u32 addr, len, rem;
>   	int ret, err;
>   
>   	dev_dbg(nor->dev, "at 0x%llx, len %lld\n", (long long)instr->addr,
> @@ -991,6 +996,19 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
>   			ret = -EINTR;
>   			goto erase_err;
>   		}
> +
> +		offset = addr;
> +		if (nor->flags & SNOR_F_HAS_PARALLEL)
> +			offset /= 2;
> +
> +		if (nor->flags & SNOR_F_HAS_STACKED) {
> +			if (offset >= (mtd->size / 2)) {
> +				offset = offset - (mtd->size / 2);
> +				nor->spi->flags |= SPI_XFER_U_PAGE;
> +			} else {
> +				nor->spi->flags &= ~SPI_XFER_U_PAGE;
> +			}
> +		}
>   #ifdef CONFIG_SPI_FLASH_BAR
>   		ret = write_bar(nor, addr);
>   		if (ret < 0)
> @@ -1394,6 +1412,9 @@ static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
>   	u8			id[SPI_NOR_MAX_ID_LEN];
>   	const struct flash_info	*info;
>   
> +	if (nor->flags & SNOR_F_HAS_PARALLEL)
> +		nor->spi->flags |= SPI_XFER_LOWER;
> +
>   	tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
>   	if (tmp < 0) {
>   		dev_dbg(nor->dev, "error %d reading JEDEC ID\n", tmp);
> @@ -1418,28 +1439,57 @@ static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
>   {
>   	struct spi_nor *nor = mtd_to_spi_nor(mtd);
>   	int ret;
> +	u32 offset = from;
> +	u32 stack_shift = 0;
> +	u32 read_len = 0;
> +	u32 rem_bank_len = 0;
> +	u8 bank;
> +	u8 is_ofst_odd = 0;
>   
>   	dev_dbg(nor->dev, "from 0x%08x, len %zd\n", (u32)from, len);
>   
> -	while (len) {
> -		loff_t addr = from;
> -		size_t read_len = len;
> +	if ((nor->flags & SNOR_F_HAS_PARALLEL) && (offset & 1)) {
> +	    /* We can hit this case when we use file system like ubifs */
> +		from = (loff_t)(from - 1);
> +		len = (size_t)(len + 1);
> +		is_ofst_odd = 1;
> +	}
>   
> -#ifdef CONFIG_SPI_FLASH_BAR
> -		u32 remain_len;
> +	while (len) {
> +		if (nor->addr_width == 3) {
> +			if (nor->flags & SNOR_F_HAS_PARALLEL) {
> +				bank = (u32)from / (SZ_16M << 0x01);
> +				rem_bank_len = ((SZ_16M << 0x01) *
> +					(bank + 1)) - from;
> +			} else {
> +				bank = (u32)from / SZ_16M;
> +				rem_bank_len = (SZ_16M * (bank + 1)) - from;
> +			}
> +		}
> +		offset = from;
> +
> +		if (nor->flags & SNOR_F_HAS_STACKED) {
> +			stack_shift = 1;
> +			if (offset >= (mtd->size / 2)) {
> +				offset = offset - (mtd->size / 2);
> +				nor->spi->flags |= SPI_XFER_U_PAGE;
> +			} else {
> +				nor->spi->flags &= ~SPI_XFER_U_PAGE;
> +			}
> +		}
>   
> -		ret = write_bar(nor, addr);
> -		if (ret < 0)
> -			return log_ret(ret);
> -		remain_len = (SZ_16M * (nor->bank_curr + 1)) - addr;
> +		if (nor->flags & SNOR_F_HAS_PARALLEL)
> +			offset /= 2;
>   
> -		if (len < remain_len)
> -			read_len = len;
> -		else
> -			read_len = remain_len;
> +		if (nor->addr_width == 3) {
> +#ifdef CONFIG_SPI_FLASH_BAR
> +			ret = write_bar(nor, offset);
> +			if (ret < 0)
> +				return log_ret(ret);
>   #endif
> +		}
>   
> -		ret = nor->read(nor, addr, read_len, buf);
> +		ret = nor->read(nor, offset, read_len, buf);
>   		if (ret == 0) {
>   			/* We shouldn't see 0-length reads */
>   			ret = -EIO;
> @@ -1741,6 +1791,7 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
>   	struct spi_nor *nor = mtd_to_spi_nor(mtd);
>   	size_t page_offset, page_remain, i;
>   	ssize_t ret;
> +	u32 offset;
>   
>   #ifdef CONFIG_SPI_FLASH_SST
>   	/* sst nor chips use AAI word program */
> @@ -1750,6 +1801,27 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
>   
>   	dev_dbg(nor->dev, "to 0x%08x, len %zd\n", (u32)to, len);
>   
> +	if (!len)
> +		return 0;
> +
> +	/*
> +	 * Cannot write to odd offset in parallel mode,
> +	 * so write 2 bytes first
> +	 */
> +	if ((nor->flags & SNOR_F_HAS_PARALLEL) && (to & 1)) {
> +		u8 two[2] = {0xff, buf[0]};
> +		size_t local_retlen;
> +
> +		ret = spi_nor_write(mtd, to & ~1, 2, &local_retlen, two);
> +		if (ret < 0)
> +			return ret;
> +
> +		*retlen += 1; /* We've written only one actual byte */
> +		++buf;
> +		--len;
> +		++to;
> +	}
> +
>   	for (i = 0; i < len; ) {
>   		ssize_t written;
>   		loff_t addr = to + i;
> @@ -1767,17 +1839,37 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
>   
>   			page_offset = do_div(aux, nor->page_size);
>   		}
> -		/* the size of data remaining on the first page */
> -		page_remain = min_t(size_t,
> -				    nor->page_size - page_offset, len - i);
>   
> +		offset = (to + i);
> +		if (nor->flags & SNOR_F_HAS_PARALLEL)
> +			offset /= 2;
> +
> +		if (nor->flags & SNOR_F_HAS_STACKED) {
> +			if (offset >= (mtd->size / 2)) {
> +				offset = offset - (mtd->size / 2);
> +				nor->spi->flags |= SPI_XFER_U_PAGE;
> +			} else {
> +				nor->spi->flags &= ~SPI_XFER_U_PAGE;
> +			}
> +		}
> +
> +		if (nor->addr_width == 3) {
>   #ifdef CONFIG_SPI_FLASH_BAR
> -		ret = write_bar(nor, addr);
> -		if (ret < 0)
> -			return ret;
> +			ret = write_bar(nor, offset);
> +			if (ret < 0)
> +				return ret;
>   #endif
> +		}
> +
> +		page_remain = min_t(size_t, nor->page_size - page_offset,
> +				    len - i);
> +
> +		ret = spi_nor_wait_till_ready(nor);
> +		if (ret)
> +			goto write_err;
> +
>   		write_enable(nor);
> -		ret = nor->write(nor, addr, page_remain, buf + i);
> +		ret = nor->write(nor, offset, page_remain, buf + i);
>   		if (ret < 0)
>   			goto write_err;
>   		written = ret;
> @@ -1785,8 +1877,20 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
>   		ret = spi_nor_wait_till_ready(nor);
>   		if (ret)
>   			goto write_err;
> +
> +		ret = write_disable(nor);
> +		if (ret)
> +			goto write_err;
> +
>   		*retlen += written;
>   		i += written;
> +		if (written != page_remain) {
> +			dev_err(nor->dev,
> +				"While writing %zu bytes written %zd bytes\n",
> +				page_remain, written);
> +			ret = -EIO;
> +			goto write_err;
> +		}
>   	}
>   
>   write_err:
> @@ -1825,6 +1929,10 @@ static int macronix_quad_enable(struct spi_nor *nor)
>   	if (ret)
>   		return ret;
>   
> +	ret = write_disable(nor);
> +	if (ret)
> +		return ret;
> +
>   	ret = read_sr(nor);
>   	if (!(ret > 0 && (ret & SR_QUAD_EN_MX))) {
>   		dev_err(nor->dev, "Macronix Quad bit not set\n");
> @@ -1886,7 +1994,7 @@ static int spansion_quad_enable_volatile(struct spi_nor *nor, u32 addr_base,
>   		return -EINVAL;
>   	}
>   
> -	return 0;
> +	return write_disable(nor);
>   }
>   #endif
>   
> @@ -2062,6 +2170,10 @@ static int spi_nor_read_sfdp(struct spi_nor *nor, u32 addr,
>   	nor->read_dummy = 8;
>   
>   	while (len) {
> +		/* Both chips are identical, so should be the SFDP data */
> +		if (nor->flags & SNOR_F_HAS_PARALLEL)
> +			nor->spi->flags |= SPI_XFER_LOWER;
> +
>   		ret = nor->read(nor, addr, len, (u8 *)buf);
>   		if (!ret || ret > len) {
>   			ret = -EIO;
> @@ -2726,6 +2838,11 @@ static int spi_nor_init_params(struct spi_nor *nor,
>   			       const struct flash_info *info,
>   			       struct spi_nor_flash_parameter *params)
>   {
> +	struct udevice *dev = nor->spi->dev;
> +	u64 flash_size[SNOR_FLASH_CNT_MAX] = {0};
> +	u32 idx = 0, i = 0;
> +	int rc;
> +
>   	/* Set legacy flash parameters as default. */
>   	memset(params, 0, sizeof(*params));
>   
> @@ -2844,6 +2961,60 @@ static int spi_nor_init_params(struct spi_nor *nor,
>   		}
>   	}
>   
> +	/*
> +	 * The flashes that are connected in stacked mode should be of same make.
> +	 * Except the flash size all other properties are identical for all the
> +	 * flashes connected in stacked mode.
> +	 * The flashes that are connected in parallel mode should be identical.
> +	 */
> +	while (i < SNOR_FLASH_CNT_MAX) {
> +		rc = ofnode_read_u64_index(dev_ofnode(dev), "stacked-memories",
> +					   idx, &flash_size[i]);
> +		if (rc == -EINVAL) {
> +			break;
> +		} else if (rc == -EOVERFLOW) {
> +			idx++;
> +		} else {
> +			idx++;
> +			i++;
> +			if (!(nor->flags & SNOR_F_HAS_STACKED))
> +				nor->flags |= SNOR_F_HAS_STACKED;
> +			if (!(nor->spi->flags & SPI_XFER_STACKED))
> +				nor->spi->flags |= SPI_XFER_STACKED;
> +		}
> +	}
> +
> +	i = 0;
> +	idx = 0;
> +	while (i < SNOR_FLASH_CNT_MAX) {
> +		rc = ofnode_read_u64_index(dev_ofnode(dev), "parallel-memories",
> +					   idx, &flash_size[i]);
> +		if (rc == -EINVAL) {
> +			break;
> +		} else if (rc == -EOVERFLOW) {
> +			idx++;
> +		} else {
> +			idx++;
> +			i++;
> +			if (!(nor->flags & SNOR_F_HAS_PARALLEL))
> +				nor->flags |= SNOR_F_HAS_PARALLEL;
> +		}
> +	}
> +
> +	if (nor->flags & (SNOR_F_HAS_STACKED | SNOR_F_HAS_PARALLEL))
> +		for (idx = 1; idx < SNOR_FLASH_CNT_MAX; idx++)
> +			params->size += flash_size[idx];
> +
> +	/*
> +	 * In parallel-memories the erase operation is
> +	 * performed on both the flashes simultaneously
> +	 * so, double the erasesize.
> +	 */
> +	if (nor->flags & SNOR_F_HAS_PARALLEL) {
> +		nor->mtd.erasesize <<= 1;
> +		params->page_size <<= 1;
> +	}
> +
>   	spi_nor_post_sfdp_fixups(nor, params);
>   
>   	return 0;
> @@ -3158,16 +3329,54 @@ static int spi_nor_select_erase(struct spi_nor *nor,
>   	/* prefer "small sector" erase if possible */
>   	if (info->flags & SECT_4K) {
>   		nor->erase_opcode = SPINOR_OP_BE_4K;
> -		mtd->erasesize = 4096;
> +		/*
> +		 * In parallel-memories the erase operation is
> +		 * performed on both the flashes simultaneously
> +		 * so, double the erasesize.
> +		 */
> +		if (nor->flags & SNOR_F_HAS_PARALLEL)
> +			mtd->erasesize = 4096 * 2;
> +		else
> +			mtd->erasesize = 4096;
>   	} else if (info->flags & SECT_4K_PMC) {
>   		nor->erase_opcode = SPINOR_OP_BE_4K_PMC;
> -		mtd->erasesize = 4096;
> +		/*
> +		 * In parallel-memories the erase operation is
> +		 * performed on both the flashes simultaneously
> +		 * so, double the erasesize.
> +		 */
> +		if (nor->flags & SNOR_F_HAS_PARALLEL)
> +			mtd->erasesize = 4096 * 2;
> +		else
> +			mtd->erasesize = 4096;
>   	} else
>   #endif
>   	{
>   		nor->erase_opcode = SPINOR_OP_SE;
> -		mtd->erasesize = info->sector_size;
> +		/*
> +		 * In parallel-memories the erase operation is
> +		 * performed on both the flashes simultaneously
> +		 * so, double the erasesize.
> +		 */
> +		if (nor->flags & SNOR_F_HAS_PARALLEL)
> +			mtd->erasesize = info->sector_size * 2;
> +		else
> +			mtd->erasesize = info->sector_size;
>   	}
> +
> +	if ((JEDEC_MFR(info) == SNOR_MFR_SST) && info->flags & SECT_4K) {
> +		nor->erase_opcode = SPINOR_OP_BE_4K;
> +		/*
> +		 * In parallel-memories the erase operation is
> +		 * performed on both the flashes simultaneously
> +		 * so, double the erasesize.
> +		 */
> +		if (nor->flags & SNOR_F_HAS_PARALLEL)
> +			mtd->erasesize = 4096 * 2;
> +		else
> +			mtd->erasesize = 4096;
> +	}
> +
>   	return 0;
>   }
>   
> @@ -3867,6 +4076,9 @@ static int spi_nor_init(struct spi_nor *nor)
>   {
>   	int err;
>   
> +	if (nor->flags & SNOR_F_HAS_PARALLEL)
> +		nor->spi->flags |= SPI_NOR_ENABLE_MULTI_CS;
> +
>   	err = spi_nor_octal_dtr_enable(nor);
>   	if (err) {
>   		dev_dbg(nor->dev, "Octal DTR mode not supported\n");
> @@ -4033,6 +4245,7 @@ int spi_nor_scan(struct spi_nor *nor)
>   	struct spi_slave *spi = nor->spi;
>   	int ret;
>   	int cfi_mtd_nb = 0;
> +	bool shift = 0;
>   
>   #ifdef CONFIG_FLASH_CFI_MTD
>   	cfi_mtd_nb = CFI_FLASH_BANKS;
> @@ -4169,7 +4382,9 @@ int spi_nor_scan(struct spi_nor *nor)
>   		nor->addr_width = 3;
>   	}
>   
> -	if (nor->addr_width == 3 && mtd->size > SZ_16M) {
> +	if (nor->flags & (SNOR_F_HAS_PARALLEL | SNOR_F_HAS_STACKED))
> +		shift = 1;
> +	if (nor->addr_width == 3 && (mtd->size >> shift) > SZ_16M) {
>   #ifndef CONFIG_SPI_FLASH_BAR
>   		/* enable 4-byte addressing if the device exceeds 16MiB */
>   		nor->addr_width = 4;
> @@ -4179,6 +4394,7 @@ int spi_nor_scan(struct spi_nor *nor)
>   #else
>   	/* Configure the BAR - discover bank cmds and read current bank */
>   	nor->addr_width = 3;
> +	set_4byte(nor, info, 0);
>   	ret = read_bar(nor, info);
>   	if (ret < 0)
>   		return ret;
> @@ -4196,6 +4412,14 @@ int spi_nor_scan(struct spi_nor *nor)
>   	if (ret)
>   		return ret;
>   
> +	if (nor->flags & SNOR_F_HAS_STACKED) {
> +		nor->spi->flags |= SPI_XFER_U_PAGE;
> +		ret = spi_nor_init(nor);
> +		if (ret)
> +			return ret;
> +		nor->spi->flags &= ~SPI_XFER_U_PAGE;
> +	}
> +
>   	nor->rdsr_dummy = params.rdsr_dummy;
>   	nor->rdsr_addr_nbytes = params.rdsr_addr_nbytes;
>   	nor->name = info->name;
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index 2861b73edb..72206f51ad 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -13,6 +13,9 @@
>   #include <linux/mtd/mtd.h>
>   #include <spi-mem.h>
>   
> +/* In parallel configuration enable multiple CS */
> +#define SPI_NOR_ENABLE_MULTI_CS	(BIT(0) | BIT(1))
> +
>   /*
>    * Manufacturer IDs
>    *
> @@ -185,6 +188,13 @@
>   /* Status Register 2 bits. */
>   #define SR2_QUAD_EN_BIT7	BIT(7)
>   
> +/*
> + * Maximum number of flashes that can be connected
> + * in stacked/parallel configuration
> + */
> +#define SNOR_FLASH_CNT_MAX	2
> +
> +
>   /* For Cypress flash. */
>   #define SPINOR_OP_RD_ANY_REG			0x65	/* Read any register */
>   #define SPINOR_OP_WR_ANY_REG			0x71	/* Write any register */
> @@ -298,6 +308,8 @@ enum spi_nor_option_flags {
>   	SNOR_F_BROKEN_RESET	= BIT(6),
>   	SNOR_F_SOFT_RESET	= BIT(7),
>   	SNOR_F_IO_MODE_EN_VOLATILE = BIT(8),
> +	SNOR_F_HAS_STACKED	= BIT(9),
> +	SNOR_F_HAS_PARALLEL	= BIT(10),
>   };
>   
>   struct spi_nor;
> @@ -555,6 +567,7 @@ struct spi_nor {
>   	u8			bank_read_cmd;
>   	u8			bank_write_cmd;
>   	u8			bank_curr;
> +	u8			upage_prev;
>   #endif
>   	enum spi_nor_protocol	read_proto;
>   	enum spi_nor_protocol	write_proto;
> diff --git a/include/spi.h b/include/spi.h
> index 1bc18e6552..2a3ccaa754 100644
> --- a/include/spi.h
> +++ b/include/spi.h
> @@ -39,6 +39,16 @@
>   
>   #define SPI_DEFAULT_WORDLEN	8
>   
> +/* SPI transfer flags */
> +#define SPI_XFER_STRIPE	(1 << 6)
> +#define SPI_XFER_MASK	(3 << 8)
> +#define SPI_XFER_LOWER	(1 << 8)
> +#define SPI_XFER_UPPER	(2 << 8)
> +
> +/* Max no. of CS supported per spi device */
> +#define SPI_CS_CNT_MAX	2
> +
> +
>   /**
>    * struct dm_spi_bus - SPI bus info
>    *
> @@ -156,6 +166,8 @@ struct spi_slave {
>   #define SPI_XFER_BEGIN		BIT(0)	/* Assert CS before transfer */
>   #define SPI_XFER_END		BIT(1)	/* Deassert CS after transfer */
>   #define SPI_XFER_ONCE		(SPI_XFER_BEGIN | SPI_XFER_END)
> +#define SPI_XFER_U_PAGE		BIT(4)
> +#define SPI_XFER_STACKED	BIT(5)
>   };
>   
>   /**


This patch breaks sandbox64. You can see reported issue by running this command.
./test/py/test.py --bd sandbox64 --build -s -k test_ut

Thanks,
Michal


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