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

On 07/01/16 01:15, Brian Norris wrote:
> 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?
>
> [...]

Correct, I missed that.

>
>> 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.

I agree.

>
>> +
>> + /* 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.

Ack.

>> +
>> + 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.

Okay.

>
>> + 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?

You're right.

>
>> + 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.

I forgot to run coccinelle on this version of the patchset - I was still
in Christmas holiday mode ;-)

>
>> +
>> + 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?

It'd be great if you could do that.

Thanks,

Harvey

>
> 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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