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SubjectRe: [PATCH v11 2/3] mtd: nand: jz4780: driver for NAND devices on JZ4780 SoCs
Hi Harvey,

On Mon, Jan 04, 2016 at 12:34:43PM +0000, Harvey Hunt wrote:
> From: Alex Smith <alex.smith@imgtec.com>
>
> Add a driver for NAND devices connected to the NEMC on JZ4780 SoCs, as
> well as the hardware BCH controller. DMA is not currently implemented.
>
> While older 47xx SoCs also have a BCH controller, they are incompatible
> with the one in the 4780 due to differing register/bit positions, which
> would make implementing a common driver for them quite messy.
>
> Signed-off-by: Alex Smith <alex.smith@imgtec.com>
> Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Cc: Brian Norris <computersforpeace@gmail.com>
> Cc: linux-mtd@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Harvey Hunt <harvey.hunt@imgtec.com>
> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> ---
[...]

> drivers/mtd/nand/Kconfig | 7 +
> drivers/mtd/nand/Makefile | 1 +
> drivers/mtd/nand/jz4780_bch.c | 380 +++++++++++++++++++++++++++++++++++++
> drivers/mtd/nand/jz4780_bch.h | 43 +++++
> drivers/mtd/nand/jz4780_nand.c | 422 +++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 853 insertions(+)
> create mode 100644 drivers/mtd/nand/jz4780_bch.c
> create mode 100644 drivers/mtd/nand/jz4780_bch.h
> create mode 100644 drivers/mtd/nand/jz4780_nand.c
>
> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
> index 2896640..b742adc 100644
> --- a/drivers/mtd/nand/Kconfig
> +++ b/drivers/mtd/nand/Kconfig
> @@ -519,6 +519,13 @@ config MTD_NAND_JZ4740
> help
> Enables support for NAND Flash on JZ4740 SoC based boards.
>
> +config MTD_NAND_JZ4780
> + tristate "Support for NAND on JZ4780 SoC"
> + depends on MACH_JZ4780 && JZ4780_NEMC
> + help
> + Enables support for NAND Flash connected to the NEMC on JZ4780 SoC
> + based boards, using the BCH controller for hardware error correction.
> +
> config MTD_NAND_FSMC
> tristate "Support for NAND on ST Micros FSMC"
> depends on PLAT_SPEAR || ARCH_NOMADIK || ARCH_U8500 || MACH_U300
> diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
> index 2c7f014..9e36233 100644
> --- a/drivers/mtd/nand/Makefile
> +++ b/drivers/mtd/nand/Makefile
> @@ -49,6 +49,7 @@ obj-$(CONFIG_MTD_NAND_MPC5121_NFC) += mpc5121_nfc.o
> obj-$(CONFIG_MTD_NAND_VF610_NFC) += vf610_nfc.o
> obj-$(CONFIG_MTD_NAND_RICOH) += r852.o
> obj-$(CONFIG_MTD_NAND_JZ4740) += jz4740_nand.o
> +obj-$(CONFIG_MTD_NAND_JZ4780) += jz4780_nand.o jz4780_bch.o
> obj-$(CONFIG_MTD_NAND_GPMI_NAND) += gpmi-nand/
> obj-$(CONFIG_MTD_NAND_XWAY) += xway_nand.o
> obj-$(CONFIG_MTD_NAND_BCM47XXNFLASH) += bcm47xxnflash/
> diff --git a/drivers/mtd/nand/jz4780_bch.c b/drivers/mtd/nand/jz4780_bch.c
> new file mode 100644
> index 0000000..53b2c06
> --- /dev/null
> +++ b/drivers/mtd/nand/jz4780_bch.c
> @@ -0,0 +1,380 @@
[...]

> +/**
> + * of_jz4780_bch_get() - get the BCH controller from a DT node
> + * @of_node: the node that contains a bch-controller property.
> + *
> + * Get the bch-controller property from the given device tree
> + * node and pass it to jz4780_bch_get to do the work.
> + *
> + * Return: a pointer to jz4780_bch, errors are encoded into the pointer.
> + * PTR_ERR(-EPROBE_DEFER) if the device hasn't been initialised yet.
> + */
> +struct jz4780_bch *of_jz4780_bch_get(struct device_node *of_node)
> +{
> + struct jz4780_bch *bch = NULL;
> + struct device_node *np;
> +
> + np = of_parse_phandle(of_node, "ingenic,bch-controller", 0);
> +
> + if (np) {
> + bch = jz4780_bch_get(np);
> + of_node_put(np);
> + }
> + return bch;
> +}

Don't you need to EXPORT_SYMBOL() this one?

[...]

> diff --git a/drivers/mtd/nand/jz4780_bch.h b/drivers/mtd/nand/jz4780_bch.h
> new file mode 100644
> index 0000000..bf471808
> --- /dev/null
> +++ b/drivers/mtd/nand/jz4780_bch.h
> @@ -0,0 +1,43 @@
> +/*
> + * JZ4780 BCH controller
> + *
> + * Copyright (c) 2015 Imagination Technologies
> + * Author: Alex Smith <alex.smith@imgtec.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published
> + * by the Free Software Foundation.
> + */
> +
> +#ifndef __DRIVERS_MTD_NAND_JZ4780_BCH_H__
> +#define __DRIVERS_MTD_NAND_JZ4780_BCH_H__
> +
> +#include <linux/types.h>
> +
> +struct device;
> +struct device_node;
> +struct jz4780_bch;
> +
> +/**
> + * struct jz4780_bch_params - BCH parameters
> + * @size: data bytes per ECC step.
> + * @bytes: ECC bytes per step.
> + * @strength: number of correctable bits per ECC step.
> + */
> +struct jz4780_bch_params {
> + int size;
> + int bytes;
> + int strength;
> +};
> +
> +int jz4780_bch_calculate(struct jz4780_bch *bch,
> + struct jz4780_bch_params *params,
> + const u8 *buf, u8 *ecc_code);
> +int jz4780_bch_correct(struct jz4780_bch *bch,
> + struct jz4780_bch_params *params, u8 *buf,
> + u8 *ecc_code);
> +
> +void jz4780_bch_release(struct jz4780_bch *bch);
> +struct jz4780_bch *of_jz4780_bch_get(struct device_node *np);
> +
> +#endif /* __DRIVERS_MTD_NAND_JZ4780_BCH_H__ */
> diff --git a/drivers/mtd/nand/jz4780_nand.c b/drivers/mtd/nand/jz4780_nand.c
> new file mode 100644
> index 0000000..d8ea35e
> --- /dev/null
> +++ b/drivers/mtd/nand/jz4780_nand.c
> @@ -0,0 +1,422 @@

[...]

> +static int jz4780_nand_init_ecc(struct jz4780_nand_chip *nand, struct device *dev)
> +{
> + struct nand_chip *chip = &nand->chip;
> + struct mtd_info *mtd = nand_to_mtd(chip);
> + struct jz4780_nand_controller *nfc = to_jz4780_nand_controller(chip->controller);
> + struct nand_ecclayout *layout = &nand->ecclayout;
> + u32 start, i;
> +
> + chip->ecc.bytes = fls((1 + 8) * chip->ecc.size) *
> + (chip->ecc.strength / 8);
> +
> + if (nfc->bch && chip->ecc.mode == NAND_ECC_HW) {
> + chip->ecc.hwctl = jz4780_nand_ecc_hwctl;
> + chip->ecc.calculate = jz4780_nand_ecc_calculate;
> + chip->ecc.correct = jz4780_nand_ecc_correct;
> + } else if (!nfc->bch && chip->ecc.mode == NAND_ECC_HW) {
> + dev_err(dev, "HW BCH selected, but BCH controller not found\n");
> + return -ENODEV;
> + }
> +
> + if (chip->ecc.mode == NAND_ECC_HW_SYNDROME) {
> + dev_err(dev, "ECC HW syndrome not supported\n");
> + return -EINVAL;
> + }
> +
> + if (chip->ecc.mode != NAND_ECC_NONE)
> + dev_info(dev, "using %s (strength %d, size %d, bytes %d)\n",
> + (nfc->bch) ? "hardware BCH" : "software ECC",
> + chip->ecc.strength, chip->ecc.size, chip->ecc.bytes);
> + else
> + dev_info(dev, "not using ECC\n");

Almost seems like all the above would be clearer as a switch/case
statement.

> +
> + /* The NAND core will generate the ECC layout. */
> + if (chip->ecc.mode == NAND_ECC_SOFT || chip->ecc.mode == NAND_ECC_SOFT_BCH)
> + return 0;
> +
> + /* Generate ECC layout. ECC codes are right aligned in the OOB area. */
> + layout->eccbytes = mtd->writesize / chip->ecc.size * chip->ecc.bytes;
> +
> + if (layout->eccbytes > mtd->oobsize - 2) {
> + dev_err(dev,
> + "invalid ECC config: required %d ECC bytes, but only %d are available",
> + layout->eccbytes, mtd->oobsize - 2);
> + return -EINVAL;
> + }
> +
> + start = mtd->oobsize - layout->eccbytes;
> + for (i = 0; i < layout->eccbytes; i++)
> + layout->eccpos[i] = start + i;
> +
> + layout->oobfree[0].offset = 2;
> + layout->oobfree[0].length = mtd->oobsize - layout->eccbytes - 2;
> +
> + chip->ecc.layout = layout;
> + return 0;
> +}
> +
> +static int jz4780_nand_init_chip(struct platform_device *pdev,
> + struct jz4780_nand_controller *nfc,
> + struct device_node *np,
> + unsigned int chipnr)
> +{
> + struct device *dev = &pdev->dev;
> + struct jz4780_nand_chip *nand;
> + struct jz4780_nand_cs *cs;
> + struct resource *res;
> + struct nand_chip *chip;
> + struct mtd_info *mtd;
> + const __be32 *reg;
> + int ret = 0;
> +
> + cs = &nfc->cs[chipnr];
> +
> + reg = of_get_property(np, "reg", NULL);
> + if (!reg)
> + return -EINVAL;
> +
> + cs->bank = be32_to_cpu(*reg);

Seems like you could use of_property_read_u32(). Not a big deal though.

> +
> + jz4780_nemc_set_type(nfc->dev, cs->bank, JZ4780_NEMC_BANK_NAND);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, chipnr);
> + cs->base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(cs->base))
> + return PTR_ERR(cs->base);
> +
> + nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
> + if (!nand)
> + return -ENOMEM;
> +
> + nand->busy_gpio = devm_gpiod_get_optional(dev, "rb", GPIOD_IN);
> +
> + if (IS_ERR(nand->busy_gpio)) {
> + ret = PTR_ERR(nand->busy_gpio);
> + dev_err(dev, "failed to request busy GPIO: %d\n", ret);
> + return ret;
> + } else if (nand->busy_gpio) {
> + nand->chip.dev_ready = jz4780_nand_dev_ready;
> + }
> +
> + nand->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_LOW);
> +
> + if (IS_ERR(nand->wp_gpio)) {
> + ret = PTR_ERR(nand->wp_gpio);
> + dev_err(dev, "failed to request WP GPIO: %d\n", ret);
> + return ret;
> + }
> +
> + chip = &nand->chip;
> + mtd = nand_to_mtd(chip);
> + mtd->priv = chip;
> + mtd->owner = THIS_MODULE;

You don't need this line any more.

> + mtd->name = DRV_NAME;

Looks like you have made some effort to support multiple chips. It'd be
a shame to name them all the same... Maybe use devm_kasprintf() to
construct a unique name for each chip?

> + mtd->dev.parent = dev;
> +
> + chip->IO_ADDR_R = cs->base + OFFSET_DATA;
> + chip->IO_ADDR_W = cs->base + OFFSET_DATA;
> + chip->chip_delay = RB_DELAY_US;
> + chip->options = NAND_NO_SUBPAGE_WRITE;
> + chip->select_chip = jz4780_nand_select_chip;
> + chip->cmd_ctrl = jz4780_nand_cmd_ctrl;
> + chip->ecc.mode = NAND_ECC_HW;
> + chip->controller = &nfc->controller;
> + nand_set_flash_node(chip, np);
> +
> + ret = nand_scan_ident(mtd, 1, NULL);
> + if (ret)
> + return ret;
> +
> + ret = jz4780_nand_init_ecc(nand, dev);
> + if (ret)
> + return ret;
> +
> + ret = nand_scan_tail(mtd);
> + if (ret)
> + return ret;
> +
> + ret = mtd_device_register(mtd, NULL, 0);
> + if (ret) {
> + nand_release(mtd);
> + return ret;
> + }
> +
> + list_add_tail(&nand->chip_list, &nfc->chips);
> +
> + return 0;
> +}
> +
> +static void jz4780_nand_cleanup_chips(struct jz4780_nand_controller *nfc)
> +{
> + struct jz4780_nand_chip *chip;
> +
> + while (!list_empty(&nfc->chips)) {
> + chip = list_first_entry(&nfc->chips, struct jz4780_nand_chip, chip_list);
> + nand_release(nand_to_mtd(&chip->chip));
> + list_del(&chip->chip_list);
> + }
> +}
> +
> +static int jz4780_nand_init_chips(struct jz4780_nand_controller *nfc,
> + struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *np;
> + int i = 0;
> + int ret;
> + int num_chips = of_get_child_count(dev->of_node);
> +
> + if (num_chips > nfc->num_banks) {
> + dev_err(dev, "found %d chips but only %d banks\n", num_chips, nfc->num_banks);
> + return -EINVAL;
> + }
> +
> + for_each_child_of_node(dev->of_node, np) {
> + ret = jz4780_nand_init_chip(pdev, nfc, np, i);
> + if (ret) {
> + jz4780_nand_cleanup_chips(nfc);
> + return ret;
> + }
> +
> + i++;
> + }
> +
> + return 0;
> +}
> +
> +static int jz4780_nand_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + unsigned int num_banks;
> + struct jz4780_nand_controller *nfc;
> + int ret;
> +
> + num_banks = jz4780_nemc_num_banks(dev);
> + if (num_banks == 0) {
> + dev_err(dev, "no banks found\n");
> + return -ENODEV;
> + }
> +
> + nfc = devm_kzalloc(dev, sizeof(*nfc) + (sizeof(nfc->cs[0]) * num_banks), GFP_KERNEL);
> + if (!nfc)
> + return -ENOMEM;
> +
> + /*
> + * Check for BCH HW before we call nand_scan_ident, to prevent us from
> + * having to call it again if the BCH driver returns -EPROBE_DEFER.
> + */
> + nfc->bch = of_jz4780_bch_get(dev->of_node);
> + if (IS_ERR(nfc->bch))
> + return PTR_ERR(nfc->bch);
> +
> + nfc->dev = dev;
> + nfc->num_banks = num_banks;
> +
> + spin_lock_init(&nfc->controller.lock);
> + INIT_LIST_HEAD(&nfc->chips);
> + init_waitqueue_head(&nfc->controller.wq);
> +
> + ret = jz4780_nand_init_chips(nfc, pdev);
> + if (ret)
> + if (nfc->bch)
> + jz4780_bch_release(nfc->bch);
> + return ret;

coccinelle and smatch notice that you got the bracing wrong here,
causing the rest of this function to be unreachable:

drivers/mtd/nand/jz4780_nand.c:383:2-32: code aligned with following code on line 385 [coccinelle]
drivers/mtd/nand/jz4780_nand.c:385 jz4780_nand_probe() warn: curly braces intended? [smatch]
drivers/mtd/nand/jz4780_nand.c:387 jz4780_nand_probe() info: ignoring unreachable code. [smatch]
drivers/mtd/nand/jz4780_nand.c:387 jz4780_nand_probe() warn: inconsistent indenting [smatch]

You'd only notice that when you remove the device though.

> +
> + platform_set_drvdata(pdev, nfc);
> + return 0;
> +}
> +
> +static int jz4780_nand_remove(struct platform_device *pdev)
> +{
> + struct jz4780_nand_controller *nfc = platform_get_drvdata(pdev);
> +
> + if (nfc->bch)
> + jz4780_bch_release(nfc->bch);
> +
> + jz4780_nand_cleanup_chips(nfc);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id jz4780_nand_dt_match[] = {
> + { .compatible = "ingenic,jz4780-nand" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, jz4780_nand_dt_match);
> +
> +static struct platform_driver jz4780_nand_driver = {
> + .probe = jz4780_nand_probe,
> + .remove = jz4780_nand_remove,
> + .driver = {
> + .name = DRV_NAME,
> + .of_match_table = of_match_ptr(jz4780_nand_dt_match),
> + },
> +};
> +module_platform_driver(jz4780_nand_driver);
> +
> +MODULE_AUTHOR("Alex Smith <alex@alex-smith.me.uk>");
> +MODULE_AUTHOR("Harvey Hunt <harvey.hunt@imgtec.com>");
> +MODULE_DESCRIPTION("Ingenic JZ4780 NAND driver");
> +MODULE_LICENSE("GPL v2");

I'd be OK taking this patch with the following appended diff squashed
in. Thoughts?

Brian

diff --git a/drivers/mtd/nand/jz4780_bch.c b/drivers/mtd/nand/jz4780_bch.c
index 53b2c06af5dc..5954fbfa29e9 100644
--- a/drivers/mtd/nand/jz4780_bch.c
+++ b/drivers/mtd/nand/jz4780_bch.c
@@ -314,6 +314,7 @@ struct jz4780_bch *of_jz4780_bch_get(struct device_node *of_node)
}
return bch;
}
+EXPORT_SYMBOL(of_jz4780_bch_get);

/**
* jz4780_bch_release() - release the BCH controller device
diff --git a/drivers/mtd/nand/jz4780_nand.c b/drivers/mtd/nand/jz4780_nand.c
index d8ea35ed1007..17eb9f264187 100644
--- a/drivers/mtd/nand/jz4780_nand.c
+++ b/drivers/mtd/nand/jz4780_nand.c
@@ -271,8 +271,10 @@ static int jz4780_nand_init_chip(struct platform_device *pdev,
chip = &nand->chip;
mtd = nand_to_mtd(chip);
mtd->priv = chip;
- mtd->owner = THIS_MODULE;
- mtd->name = DRV_NAME;
+ mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%s.%d", dev_name(dev),
+ cs->bank);
+ if (!mtd->name)
+ return -ENOMEM;
mtd->dev.parent = dev;

chip->IO_ADDR_R = cs->base + OFFSET_DATA;
@@ -379,10 +381,11 @@ static int jz4780_nand_probe(struct platform_device *pdev)
init_waitqueue_head(&nfc->controller.wq);

ret = jz4780_nand_init_chips(nfc, pdev);
- if (ret)
+ if (ret) {
if (nfc->bch)
jz4780_bch_release(nfc->bch);
return ret;
+ }

platform_set_drvdata(pdev, nfc);
return 0;

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