Re: [PATCH v3 8/9] mtd: rawnand: ingenic: Add support for the JZ4725B

[Paul Cercueil <paul@xxxxxxxxxxxxxxx>]

Hi Miquel,

> Hi Paul,
>
> Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote on Mon,  4 Feb 2019 
> 16:04:25
> -0300:
>
> >  The boot ROM of the JZ4725B SoC expects a specific OOB layout on the
> >  NAND, so we use it unconditionally in the ingenic-nand driver.
> >
> >  Also add the jz4725b-bch driver to support the JZ4725B-specific BCH
> >  hardware.
> >
> >  Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> >  ---
> >
> >  Changes:
> >
> >  v2: Instead of forcing the OOB layout, leave it to the board code or
> >      devicetree to decide if the jz4725b-specific layout should be 
> > used
> >      or not.
> >
> >  v3: - Revert the change in v2, as the previous behaviour was 
> > correct.
> >      - Also add support for the hardware BCH of the JZ4725B in this
> >        patch.
> >
> >   drivers/mtd/nand/raw/ingenic/Kconfig        |  10 ++
> >   drivers/mtd/nand/raw/ingenic/Makefile       |   1 +
> >   drivers/mtd/nand/raw/ingenic/ingenic_nand.c |  48 +++++-
> >   drivers/mtd/nand/raw/ingenic/jz4725b_bch.c  | 251 
> > ++++++++++++++++++++++++++++
> >   4 files changed, 309 insertions(+), 1 deletion(-)
> >   create mode 100644 drivers/mtd/nand/raw/ingenic/jz4725b_bch.c
> >
> >  diff --git a/drivers/mtd/nand/raw/ingenic/Kconfig 
> > b/drivers/mtd/nand/raw/ingenic/Kconfig
> >  index cc663cc15119..497b46b144f2 100644
> >  --- a/drivers/mtd/nand/raw/ingenic/Kconfig
> >  +++ b/drivers/mtd/nand/raw/ingenic/Kconfig
> >  @@ -27,6 +27,16 @@ config MTD_NAND_JZ4740_ECC
> >   	  This driver can also be built as a module. If so, the module
> >   	  will be called jz4740-ecc.
> >
> >  +config MTD_NAND_JZ4725B_BCH
> >  +	tristate "Hardware BCH support for JZ4725B SoC"
> >  +	select MTD_NAND_INGENIC_ECC
> >  +	help
> >  +	  Enable this driver to support the BCH error-correction hardware
> >  +	  present on the JZ4725B SoC from Ingenic.
> >  +
> >  +	  This driver can also be built as a module. If so, the module
> >  +	  will be called jz4725b-bch.
> >  +
> >   config MTD_NAND_JZ4780_BCH
> >   	tristate "Hardware BCH support for JZ4780 SoC"
> >   	select MTD_NAND_INGENIC_ECC
> >  diff --git a/drivers/mtd/nand/raw/ingenic/Makefile 
> > b/drivers/mtd/nand/raw/ingenic/Makefile
> >  index 563b7effcf59..ab2c5f47e5b7 100644
> >  --- a/drivers/mtd/nand/raw/ingenic/Makefile
> >  +++ b/drivers/mtd/nand/raw/ingenic/Makefile
> >  @@ -3,4 +3,5 @@ obj-$(CONFIG_MTD_NAND_JZ4780) += ingenic_nand.o
> >
> >   obj-$(CONFIG_MTD_NAND_INGENIC_ECC) += ingenic_ecc.o
> >   obj-$(CONFIG_MTD_NAND_JZ4740_ECC) += jz4740_ecc.o
> >  +obj-$(CONFIG_MTD_NAND_JZ4725B_BCH) += jz4725b_bch.o
> >   obj-$(CONFIG_MTD_NAND_JZ4780_BCH) += jz4780_bch.o
> >  diff --git a/drivers/mtd/nand/raw/ingenic/ingenic_nand.c 
> > b/drivers/mtd/nand/raw/ingenic/ingenic_nand.c
> >  index 3fd078920b17..0e6d79993ff3 100644
> >  --- a/drivers/mtd/nand/raw/ingenic/ingenic_nand.c
> >  +++ b/drivers/mtd/nand/raw/ingenic/ingenic_nand.c
> >  @@ -34,6 +34,7 @@ struct jz_soc_info {
> >   	unsigned long data_offset;
> >   	unsigned long addr_offset;
> >   	unsigned long cmd_offset;
> >  +	const struct mtd_ooblayout_ops *oob_layout;
> >   };
> >
> >   struct ingenic_nand_cs {
> >  @@ -71,6 +72,41 @@ static inline struct ingenic_nfc 
> > *to_ingenic_nfc(struct nand_controller *ctrl)
> >   	return container_of(ctrl, struct ingenic_nfc, controller);
> >   }
> >
> >  +static int jz4725b_ooblayout_ecc(struct mtd_info *mtd, int section,
> >  +				 struct mtd_oob_region *oobregion)
> >  +{
> >  +	struct nand_chip *chip = mtd_to_nand(mtd);
> >  +	struct nand_ecc_ctrl *ecc = &chip->ecc;
> >  +
> >  +	if (section || !ecc->total)
> >  +		return -ERANGE;
> >  +
> >  +	oobregion->length = ecc->total;
> >  +	oobregion->offset = 3;
> >  +
> >  +	return 0;
> >  +}
> >  +
> >  +static int jz4725b_ooblayout_free(struct mtd_info *mtd, int 
> > section,
> >  +				  struct mtd_oob_region *oobregion)
> >  +{
> >  +	struct nand_chip *chip = mtd_to_nand(mtd);
> >  +	struct nand_ecc_ctrl *ecc = &chip->ecc;
> >  +
> >  +	if (section)
> >  +		return -ERANGE;
> >  +
> >  +	oobregion->length = mtd->oobsize - ecc->total - 3;
> >  +	oobregion->offset = 3 + ecc->total;
> >  +
> >  +	return 0;
> >  +}
> >  +
> >  +const struct mtd_ooblayout_ops jz4725b_ooblayout_ops = {
> >  +	.ecc = jz4725b_ooblayout_ecc,
> >  +	.free = jz4725b_ooblayout_free,
> >  +};
> >  +
> >   static void ingenic_nand_select_chip(struct nand_chip *chip, int 
> > chipnr)
> >   {
> >   	struct ingenic_nand *nand = to_ingenic_nand(nand_to_mtd(chip));
> >  @@ -211,7 +247,7 @@ static int ingenic_nand_attach_chip(struct 
> > nand_chip *chip)
> >   		return -EINVAL;
> >   	}
> >
> >  -	mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
> >  +	mtd_set_ooblayout(mtd, nfc->soc_info->oob_layout);
> >
> >   	return 0;
> >   }
> >  @@ -407,16 +443,26 @@ static const struct jz_soc_info 
> > jz4740_soc_info = {
> >   	.data_offset = 0x00000000,
> >   	.cmd_offset  = 0x00008000,
> >   	.addr_offset = 0x00010000,
> >  +	.oob_layout = &nand_ooblayout_lp_ops,
> >  +};
> >  +
> >  +static const struct jz_soc_info jz4725b_soc_info = {
> >  +	.data_offset = 0x00000000,
> >  +	.cmd_offset  = 0x00008000,
> >  +	.addr_offset = 0x00010000,
> >  +	.oob_layout = &jz4725b_ooblayout_ops,
> >   };
> >
> >   static const struct jz_soc_info jz4780_soc_info = {
> >   	.data_offset = 0x00000000,
> >   	.cmd_offset  = 0x00400000,
> >   	.addr_offset = 0x00800000,
> >  +	.oob_layout = &nand_ooblayout_lp_ops,
> >   };
> >
> >   static const struct of_device_id ingenic_nand_dt_match[] = {
> >   	{ .compatible = "ingenic,jz4740-nand", .data = &jz4740_soc_info },
> >  +	{ .compatible = "ingenic,jz4725b-nand", .data = &jz4725b_soc_info 
> > },
> >   	{ .compatible = "ingenic,jz4780-nand",  .data = &jz4780_soc_info  
> > },
> >   	{},
> >   };
> >  diff --git a/drivers/mtd/nand/raw/ingenic/jz4725b_bch.c 
> > b/drivers/mtd/nand/raw/ingenic/jz4725b_bch.c
> >  new file mode 100644
> >  index 000000000000..66be454be383
> >  --- /dev/null
> >  +++ b/drivers/mtd/nand/raw/ingenic/jz4725b_bch.c
> >  @@ -0,0 +1,251 @@
> >  +// SPDX-License-Identifier: GPL-2.0
> >  +/*
> >  + * JZ4725B BCH controller driver
> >  + *
> >  + * Copyright (C) 2018 Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> >  + *
> >  + * Based on jz4780_bch.c
> >  + */
> >  +
> >  +#include <linux/bitops.h>
> >  +#include <linux/device.h>
> >  +#include <linux/io.h>
> >  +#include <linux/iopoll.h>
> >  +#include <linux/module.h>
> >  +#include <linux/mutex.h>
> >  +#include <linux/of_platform.h>
> >  +#include <linux/platform_device.h>
> >  +
> >  +#include "ingenic_ecc.h"
> >  +
> >  +#define BCH_BHCR			0x0
> >  +#define BCH_BHCSR			0x4
> >  +#define BCH_BHCCR			0x8
> >  +#define BCH_BHCNT			0xc
> >  +#define BCH_BHDR			0x10
> >  +#define BCH_BHPAR0			0x14
> >  +#define BCH_BHERR0			0x28
> >  +#define BCH_BHINT			0x24
> >  +#define BCH_BHINTES			0x3c
> >  +#define BCH_BHINTEC			0x40
> >  +#define BCH_BHINTE			0x38
> >  +
> >  +#define BCH_BHCR_BSEL_SHIFT		2
> >  +#define BCH_BHCR_BSEL_MASK		(0x1 << BCH_BHCR_BSEL_SHIFT)
> >  +#define BCH_BHCR_ENCE			BIT(3)
> >  +#define BCH_BHCR_INIT			BIT(1)
> >  +#define BCH_BHCR_BCHE			BIT(0)
> >  +
> >  +#define BCH_BHCNT_DEC_COUNT_SHIFT	16
> >  +#define BCH_BHCNT_DEC_COUNT_MASK	(0x3ff << 
> > BCH_BHCNT_DEC_COUNT_SHIFT)
> >  +#define BCH_BHCNT_ENC_COUNT_SHIFT	0
> >  +#define BCH_BHCNT_ENC_COUNT_MASK	(0x3ff << 
> > BCH_BHCNT_ENC_COUNT_SHIFT)
> >  +
> >  +#define BCH_BHERR_INDEX0_SHIFT		0
> >  +#define BCH_BHERR_INDEX0_MASK		(0x1fff << BCH_BHERR_INDEX0_SHIFT)
> >  +#define BCH_BHERR_INDEX1_SHIFT		16
> >  +#define BCH_BHERR_INDEX1_MASK		(0x1fff << BCH_BHERR_INDEX1_SHIFT)
> >  +
> >  +#define BCH_BHINT_ERRC_SHIFT		28
> >  +#define BCH_BHINT_ERRC_MASK		(0xf << BCH_BHINT_ERRC_SHIFT)
> >  +#define BCH_BHINT_TERRC_SHIFT		16
> >  +#define BCH_BHINT_TERRC_MASK		(0x7f << BCH_BHINT_TERRC_SHIFT)
> >  +#define BCH_BHINT_ALL_0			BIT(5)
> >  +#define BCH_BHINT_ALL_F			BIT(4)
> >  +#define BCH_BHINT_DECF			BIT(3)
> >  +#define BCH_BHINT_ENCF			BIT(2)
> >  +#define BCH_BHINT_UNCOR			BIT(1)
> >  +#define BCH_BHINT_ERR			BIT(0)
> >  +
> >  +/* Timeout for BCH calculation/correction. */
> >  +#define BCH_TIMEOUT_US			100000
> >  +
> >  +static void jz4725b_bch_init(struct ingenic_ecc *bch,
> >  +			     struct ingenic_ecc_params *params, bool encode)
>
> I don't know the IP but 'encode' looks strange, what is it supposed to
> mean?

It is used to toggle between calculating the ECC codes for a given set 
of data,
and using supplied ECC codes to verify a set of data.

I just reused the function and parameter names that were used in the
jz4780-bch driver, that's where the 'encode' comes from.

> >  +{
> >  +	u32 reg;
> >  +
> >  +	/* Clear interrupt status. */
> >  +	writel(readl(bch->base + BCH_BHINT), bch->base + BCH_BHINT);
> >  +
> >  +	/* Initialise and enable BCH. */
> >  +	writel(0x1f, bch->base + BCH_BHCCR);
> >  +	writel(BCH_BHCR_BCHE, bch->base + BCH_BHCSR);
> >  +
> >  +	if (params->strength == 8)
> >  +		writel(BCH_BHCR_BSEL_MASK, bch->base + BCH_BHCSR);
> >  +	else
> >  +		writel(BCH_BHCR_BSEL_MASK, bch->base + BCH_BHCCR);
>
> Here you write to BCH_BHCSR or BCH_BHCCR depending on
> params->strength...
>
> >  +
> >  +	if (encode)
> >  +		writel(BCH_BHCR_ENCE, bch->base + BCH_BHCSR);
> >  +	else
> >  +		writel(BCH_BHCR_ENCE, bch->base + BCH_BHCCR);
>
> ...and here depending on encode.
>
> Can you explain a bit?

BCH_BHCSR / BCH_BHCCR are set and clear registers for the BCH_BHCR
register, which is itself read-only. The BSEL field is used to toggle
between a strength of 4 (if cleared) and 8 (if set), while the ENCE
field configures the IP for 'encoding' mode.

> >  +
> >  +	writel(BCH_BHCR_INIT, bch->base + BCH_BHCSR);
> >  +
> >  +	/* Set up BCH count register. */
> >  +	reg = params->size << BCH_BHCNT_ENC_COUNT_SHIFT;
> >  +	reg |= (params->size + params->bytes) << 
> > BCH_BHCNT_DEC_COUNT_SHIFT;
>
> Maybe you want to check params->size to fit the bitfield length?

I guess I could do that, yes.

> >  +	writel(reg, bch->base + BCH_BHCNT);
> >  +}
> >  +
> >  +static void jz4725b_bch_disable(struct ingenic_ecc *bch)
> >  +{
> >  +	writel(readl(bch->base + BCH_BHINT), bch->base + BCH_BHINT);
> >  +	writel(BCH_BHCR_BCHE, bch->base + BCH_BHCCR);
>
> I would add comments, one to say you clear the interrupts, one when 
> you
> disable the engine.

OK.

> >  +}
> >  +
> >  +static void jz4725b_bch_write_data(struct ingenic_ecc *bch, const 
> > u8 *buf,
> >  +				   size_t size)
> >  +{
> >  +	while (size--)
> >  +		writeb(*buf++, bch->base + BCH_BHDR);
> >  +}
> >  +
> >  +static void jz4725b_bch_read_parity(struct ingenic_ecc *bch, u8 
> > *buf,
> >  +				    size_t size)
> >  +{
> >  +	size_t size32 = size / sizeof(u32);
> >  +	size_t size8 = size % sizeof(u32);
> >  +	u32 *dest32;
> >  +	u8 *dest8;
> >  +	u32 val, offset = 0;
> >  +
> >  +	dest32 = (u32 *)buf;
> >  +	while (size32--) {
> >  +		*dest32++ = readl(bch->base + BCH_BHPAR0 + offset);
> >  +		offset += sizeof(u32);
> >  +	}
> >  +
> >  +	dest8 = (u8 *)dest32;
> >  +	val = readl(bch->base + BCH_BHPAR0 + offset);
> >  +	switch (size8) {
> >  +	case 3:
> >  +		dest8[2] = (val >> 16) & 0xff;
> >  +	case 2:
> >  +		dest8[1] = (val >> 8) & 0xff;
> >  +	case 1:
> >  +		dest8[0] = val & 0xff;
> >  +		break;
> >  +	}
> >  +}
>
> Have you tried with _relaxed operators?

Never heard about these :)

> >  +
> >  +static bool jz4725b_bch_wait_complete(struct ingenic_ecc *bch, 
> > unsigned int irq,
> >  +				      u32 *status)
> >  +{
> >  +	u32 reg;
> >  +	int ret;
> >  +
> >  +	/*
> >  +	 * While we could use interrupts here and sleep until the 
> > operation
> >  +	 * completes, the controller works fairly quickly (usually a few
> >  +	 * microseconds) and so the overhead of sleeping until we get an
> >  +	 * interrupt quite noticeably decreases performance.
> >  +	 */
> >  +	ret = readl_poll_timeout(bch->base + BCH_BHINT, reg,
> >  +				 (reg & irq) == irq, 0, BCH_TIMEOUT_US);
>
> I suppose (reg & irq) is enough?
>
> >  +	if (ret)
> >  +		return false;
> >  +
> >  +	if (status)
> >  +		*status = reg;
> >  +
> >  +	writel(reg, bch->base + BCH_BHINT);
>
> space
>
> >  +	return true;
> >  +}
> >  +
> >  +static int jz4725b_calculate(struct ingenic_ecc *bch,
> >  +			     struct ingenic_ecc_params *params,
> >  +			     const u8 *buf, u8 *ecc_code)
> >  +{
> >  +	int ret = 0;
> >  +
> >  +	mutex_lock(&bch->lock);
> >  +	jz4725b_bch_init(bch, params, true);
> >  +	jz4725b_bch_write_data(bch, buf, params->size);
> >  +
> >  +	if (jz4725b_bch_wait_complete(bch, BCH_BHINT_ENCF, NULL)) {
>
> I would prefer bch_wait_complete() to return an usual negative error
> instead of a boolean.
>
> And maybe a goto could be used in case of error to disable BCH, unlock
> the mutex and return.

OK.

> >  +		jz4725b_bch_read_parity(bch, ecc_code, params->bytes);
> >  +	} else {
> >  +		dev_err(bch->dev, "timed out while calculating ECC\n");
> >  +		ret = -ETIMEDOUT;
> >  +	}
> >  +
> >  +	jz4725b_bch_disable(bch);
> >  +	mutex_unlock(&bch->lock);
>
> Space
>
> >  +	return ret;
> >  +}
> >  +
> >  +static int jz4725b_correct(struct ingenic_ecc *bch,
> >  +			   struct ingenic_ecc_params *params,
> >  +			   u8 *buf, u8 *ecc_code)
> >  +{
> >  +	u32 reg, errors, bit;
> >  +	unsigned int i;
> >  +	int ret = 0;
> >  +
> >  +	mutex_lock(&bch->lock);
> >  +
> >  +	jz4725b_bch_init(bch, params, false);
> >  +	jz4725b_bch_write_data(bch, buf, params->size);
> >  +	jz4725b_bch_write_data(bch, ecc_code, params->bytes);
> >  +
> >  +	if (!jz4725b_bch_wait_complete(bch, BCH_BHINT_DECF, &reg)) {
> >  +		dev_err(bch->dev, "timed out while correcting data\n");
> >  +		ret = -ETIMEDOUT;
> >  +		goto out;
> >  +	}
> >  +
> >  +	if (reg & (BCH_BHINT_ALL_F | BCH_BHINT_ALL_0)) {
> >  +		/* Data and ECC is all 0xff or 0x00 - nothing to correct */
> >  +		ret = 0;
> >  +		goto out;
> >  +	}
> >  +
> >  +	if (reg & BCH_BHINT_UNCOR) {
> >  +		/* Uncorrectable ECC error */
> >  +		ret = -EBADMSG;
> >  +		goto out;
> >  +	}
> >  +
> >  +	errors = (reg & BCH_BHINT_ERRC_MASK) >> BCH_BHINT_ERRC_SHIFT;
> >  +
> >  +	/* Correct any detected errors. */
> >  +	for (i = 0; i < errors; i++) {
> >  +		if (i & 1) {
> >  +			bit = (reg & BCH_BHERR_INDEX1_MASK) >> BCH_BHERR_INDEX1_SHIFT;
> >  +		} else {
> >  +			reg = readl(bch->base + BCH_BHERR0 + (i * 4));
> >  +			bit = (reg & BCH_BHERR_INDEX0_MASK) >> BCH_BHERR_INDEX0_SHIFT;
> >  +		}
> >  +
> >  +		buf[(bit >> 3)] ^= BIT(bit & 0x7);
> >  +	}
> >  +
> >  +out:
> >  +	jz4725b_bch_disable(bch);
> >  +	mutex_unlock(&bch->lock);
> >  +	return ret;
> >  +}
> >  +
> >  +static const struct ingenic_ecc_ops jz4725b_bch_ops = {
> >  +	.disable = jz4725b_bch_disable,
> >  +	.calculate = jz4725b_calculate,
> >  +	.correct = jz4725b_correct,
> >  +};
> >  +
> >  +static const struct of_device_id jz4725b_bch_dt_match[] = {
> >  +	{ .compatible = "ingenic,jz4725b-bch", .data = &jz4725b_bch_ops },
> >  +	{},
> >  +};
> >  +MODULE_DEVICE_TABLE(of, jz4725b_bch_dt_match);
> >  +
> >  +static struct platform_driver jz4725b_bch_driver = {
> >  +	.probe		= ingenic_ecc_probe,
> >  +	.driver	= {
> >  +		.name	= "jz4725b-bch",
> >  +		.of_match_table = jz4725b_bch_dt_match,
> >  +	},
> >  +};
> >  +module_platform_driver(jz4725b_bch_driver);
>
> Missing MODULE_ macros? (author, license)

You're right, I will add them.

Thanks,
-Paul