Re: [PATCH v9 2/3] mtd: nand: jz4780: driver for NAND devices on JZ4780 SoCs

From: Harvey Hunt
Date: Wed Dec 16 2015 - 06:00:56 EST

Hi Boris,

That's fine - I hope to get a new version ready soon.

Thanks,

Harvey

On 14/12/15 16:25, Boris Brezillon wrote:
Hi Harvey,

I'm currently reworking the NAND subsystem to simplify NAND controller
drivers (see this series [1]), and some of my patches have made it into
Brian's tree.
Would you mind adapting your driver as described below so that I don't
have to do it when it gets applied into l2-mtd/master?

On Thu, 3 Dec 2015 12:02:21 +0000
Harvey Hunt <harvey.hunt@xxxxxxxxxx> wrote:

From: Alex Smith <alex.smith@xxxxxxxxxx>

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@xxxxxxxxxx>
Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@xxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Brian Norris <computersforpeace@xxxxxxxxx>
Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Harvey Hunt <harvey.hunt@xxxxxxxxxx>
---
v8 -> v9:
- No change.

v7 -> v8:
- Rebase to 4.4-rc3.
- Add _US suffixes to time constants.
- Add locking to BCH hardware accesses.
- Don't print ECC info if ECC is not being used.
- Default to No ECC.
- Let the NAND core handle ECC layout in certain cases.
- Use the gpio_desc consumer interface.
- Removed gpio active low flags.
- Check for the BCH controller before initialising a chip.
- Add a jz4780_nand_controller struct.
- Initialise chips by iterating over DT child nodes.

v6 -> v7:
- Add nand-ecc-mode to DT bindings.
- Add nand-on-flash-bbt to DT bindings.

v5 -> v6:
- No change.

v4 -> v5:
- Rename ingenic,bch-device to ingenic,bch-controller to fit with
existing convention.

v3 -> v4:
- No change

v2 -> v3:
- Rebase to 4.0-rc6
- Changed ingenic,ecc-size to common nand-ecc-step-size
- Changed ingenic,ecc-strength to common nand-ecc-strength
- Changed ingenic,busy-gpio to common rb-gpios
- Changed ingenic,wp-gpio to common wp-gpios

v1 -> v2:
- Rebase to 4.0-rc3

drivers/mtd/nand/Kconfig | 7 +
drivers/mtd/nand/Makefile | 1 +
drivers/mtd/nand/jz4780_bch.c | 361 +++++++++++++++++++++++++++++++++++
drivers/mtd/nand/jz4780_bch.h | 42 +++++
drivers/mtd/nand/jz4780_nand.c | 420 +++++++++++++++++++++++++++++++++++++++++
5 files changed, 831 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/jz4780_nand.c b/drivers/mtd/nand/jz4780_nand.c
new file mode 100644
index 0000000..b4d0acb
--- /dev/null
+++ b/drivers/mtd/nand/jz4780_nand.c
@@ -0,0 +1,420 @@
+/*
+ * JZ4780 NAND driver
+ *
+ * Copyright (c) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@xxxxxxxxxx>
+ *
+ * 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.
+ */
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of_mtd.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+
+#include <linux/jz4780-nemc.h>
+
+#include "jz4780_bch.h"
+
+#define DRV_NAME "jz4780-nand"
+
+#define OFFSET_DATA 0x00000000
+#define OFFSET_CMD 0x00400000
+#define OFFSET_ADDR 0x00800000
+
+/* Command delay when there is no R/B pin. */
+#define RB_DELAY_US 100
+
+struct jz4780_nand_cs {
+ unsigned int bank;
+ void __iomem *base;
+};
+
+struct jz4780_nand_controller {
+ struct device *dev;
+ struct device *bch;
+ struct nand_hw_control controller;
+ unsigned int num_banks;
+ struct list_head chips;
+ int selected;
+ struct jz4780_nand_cs cs[];
+};
+
+struct jz4780_nand_chip {
+ struct mtd_info mtd;

You can drop the mtd field, since nand_chip now embeds its own mtd
instance. This implies doing the following changes...

+ struct nand_chip chip;
+ struct list_head chip_list;
+
+ struct nand_ecclayout ecclayout;
+
+ struct gpio_desc *busy_gpio;
+ struct gpio_desc *wp_gpio;
+ unsigned int reading: 1;
+};
+
+static inline struct jz4780_nand_chip *to_jz4780_nand_chip(struct mtd_info *mtd)
+{
+ return container_of(mtd, struct jz4780_nand_chip, mtd);

return container_of(mtd_to_nand(mtd), struct jz4780_nand_chip,
chip);

+}
+

[...]

+static int jz4780_nand_ecc_correct(struct mtd_info *mtd, uint8_t *dat,
+ uint8_t *read_ecc, uint8_t *calc_ecc)
+{
+ struct jz4780_nand_chip *nand = to_jz4780_nand_chip(mtd);
+ struct jz4780_nand_controller *nfc = to_jz4780_nand_controller(nand->chip.controller);
+ struct jz4780_bch_params params;
+
+ params.size = nand->chip.ecc.size;
+ params.bytes = nand->chip.ecc.bytes;
+ params.strength = nand->chip.ecc.strength;
+
+ return jz4780_bch_correct(nfc->bch, &params, dat, read_ecc);
+}
+
+static int jz4780_nand_init_ecc(struct jz4780_nand_chip *nand, struct device *dev)
+{
+ struct mtd_info *mtd = &nand->mtd;
+ struct nand_chip *chip = &nand->chip;
+ struct jz4780_nand_controller *nfc = to_jz4780_nand_controller(nand->chip.controller);

You can reuse the local chip variable here:

struct jz4780_nand_controller *nfc =
to_jz4780_nand_controller(chip->controller);

+ struct nand_ecclayout *layout = &nand->ecclayout;
+ uint32_t 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_NONE)
+ dev_info(dev, "using %s BCH (strength %d, size %d, bytes %d)\n",
+ (nfc->bch) ? "hardware" : "software", chip->ecc.strength,
+ chip->ecc.size, chip->ecc.bytes);
+ else
+ dev_info(dev, "not using ECC\n");
+
+ /* 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;
+ 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;
+ struct mtd_part_parser_data ppdata;
+ int ret = 0;
+
+ cs = &nfc->cs[chipnr];
+
+ reg = of_get_property(np, "reg", NULL);
+ if (reg == NULL)
+ return -EINVAL;
+
+ cs->bank = be32_to_cpu(*reg);
+
+ 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;
+ }
+
+ mtd = &nand->mtd;
+ chip = &nand->chip;

Please replace the two lines above lines by:

chip = &nand->chip;
mtd = nand_to_mtd(chip);

+ mtd->priv = chip;
+ mtd->owner = THIS_MODULE;
+ mtd->name = DRV_NAME;
+ mtd->dev.parent = dev;
+
+ chip->flash_node = np;
+ 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;
+
+ 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)
+ goto err_release_bch;
+
+ ppdata.of_node = np;
+ ret = mtd_device_parse_register(mtd, NULL, &ppdata, NULL, 0);
+ if (ret)
+ goto err_release_nand;
+
+ return 0;
+
+err_release_nand:
+ nand_release(mtd);
+
+err_release_bch:
+ if (nfc->bch)
+ jz4780_bch_release(nfc->bch);
+
+ return ret;
+}
+
+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)
+ 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;
+ struct device_node *bch_np;
+ 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.
+ */
+ bch_np = of_parse_phandle(dev->of_node,
+ "ingenic,bch-controller", 0);
+ if (bch_np) {
+ ret = jz4780_bch_get(bch_np, &nfc->bch);
+ of_node_put(bch_np);
+ if (ret)
+ return ret;
+ }
+
+ 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)
+ return ret;
+
+ platform_set_drvdata(pdev, nfc);
+ return 0;
+}
+
+static int jz4780_nand_remove(struct platform_device *pdev)
+{
+ struct jz4780_nand_chip *chip;
+ struct jz4780_nand_controller *nfc = platform_get_drvdata(pdev);
+
+ while (!list_empty(&nfc->chips)) {
+ chip = list_first_entry(&nfc->chips, struct jz4780_nand_chip, chip_list);
+ nand_release(&chip->mtd);

nand_release(nand_to_mtd(&chip->chip));

+ list_del(&chip->chip_list);
+ }
+
+ if (nfc->bch)
+ jz4780_bch_release(nfc->bch);
+
+ return 0;
+}

Thanks,

Boris

[1]https://lkml.org/lkml/2015/12/10/154

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