On 12.06.2018 01:32, Dmitry Osipenko wrote:
> On Monday, 11 June 2018 23:52:22 MSK Stefan Agner wrote:
>> Add support for the NAND flash controller found on NVIDIA
>> Tegra 2 SoCs. This implementation does not make use of the
>> command queue feature. Regular operations/data transfers are
>> done in PIO mode. Page read/writes with hardware ECC make
>> use of the DMA for data transfer.
> 
> Are "regular operations/data transfers" == "raw read/writes"? Seems you've 
> fixed DMA now and hence should adjust the commit message if that's the case.
> 

Yep, will fix this!

>>
>> Signed-off-by: Lucas Stach <d...@lynxeye.de>
>> Signed-off-by: Stefan Agner <ste...@agner.ch>
>> ---
> 
> Otherwise looks good to me:
> 
> Reviewed-by: Dmitry Osipenko <dig...@gmail.com>

Thanks for you review!

> 
> 
> There couple nit comments about newlines below, maybe you could clean up them 
> if there will be another revision.

Ok, will take care of them as well.

--
Stefan

> 
>>  MAINTAINERS                       |    7 +
>>  drivers/mtd/nand/raw/Kconfig      |    6 +
>>  drivers/mtd/nand/raw/Makefile     |    1 +
>>  drivers/mtd/nand/raw/tegra_nand.c | 1248 +++++++++++++++++++++++++++++
>>  4 files changed, 1262 insertions(+)
>>  create mode 100644 drivers/mtd/nand/raw/tegra_nand.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 58b9861ccf99..c2e5571c85d4 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -13844,6 +13844,13 @@ M:  Laxman Dewangan <ldewan...@nvidia.com>
>>  S:  Supported
>>  F:  drivers/input/keyboard/tegra-kbc.c
>>
>> +TEGRA NAND DRIVER
>> +M:  Stefan Agner <ste...@agner.ch>
>> +M:  Lucas Stach <d...@lynxeye.de>
>> +S:  Maintained
>> +F:  Documentation/devicetree/bindings/mtd/nvidia-tegra20-nand.txt
>> +F:  drivers/mtd/nand/raw/tegra_nand.c
>> +
>>  TEGRA PWM DRIVER
>>  M:  Thierry Reding <thierry.red...@gmail.com>
>>  S:  Supported
>> diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
>> index 19a2b283fbbe..e9093f52371e 100644
>> --- a/drivers/mtd/nand/raw/Kconfig
>> +++ b/drivers/mtd/nand/raw/Kconfig
>> @@ -534,4 +534,10 @@ config MTD_NAND_MTK
>>        Enables support for NAND controller on MTK SoCs.
>>        This controller is found on mt27xx, mt81xx, mt65xx SoCs.
>>
>> +config MTD_NAND_TEGRA
>> +    tristate "Support for NAND controller on NVIDIA Tegra"
>> +    depends on ARCH_TEGRA || COMPILE_TEST
>> +    help
>> +      Enables support for NAND flash controller on NVIDIA Tegra SoC.
>> +
>>  endif # MTD_NAND
>> diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
>> index 165b7ef9e9a1..d5a5f9832b88 100644
>> --- a/drivers/mtd/nand/raw/Makefile
>> +++ b/drivers/mtd/nand/raw/Makefile
>> @@ -56,6 +56,7 @@ obj-$(CONFIG_MTD_NAND_HISI504)             +=
> hisi504_nand.o
>>  obj-$(CONFIG_MTD_NAND_BRCMNAND)             += brcmnand/
>>  obj-$(CONFIG_MTD_NAND_QCOM)         += qcom_nandc.o
>>  obj-$(CONFIG_MTD_NAND_MTK)          += mtk_ecc.o mtk_nand.o
>> +obj-$(CONFIG_MTD_NAND_TEGRA)                += tegra_nand.o
>>
>>  nand-objs := nand_base.o nand_bbt.o nand_timings.o nand_ids.o
>>  nand-objs += nand_amd.o
>> diff --git a/drivers/mtd/nand/raw/tegra_nand.c
>> b/drivers/mtd/nand/raw/tegra_nand.c new file mode 100644
>> index 000000000000..dd23a5eb6af3
>> --- /dev/null
>> +++ b/drivers/mtd/nand/raw/tegra_nand.c
>> @@ -0,0 +1,1248 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) 2018 Stefan Agner <ste...@agner.ch>
>> + * Copyright (C) 2014-2015 Lucas Stach <d...@lynxeye.de>
>> + * Copyright (C) 2012 Avionic Design GmbH
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/completion.h>
>> +#include <linux/delay.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/err.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/module.h>
>> +#include <linux/mtd/partitions.h>
>> +#include <linux/mtd/rawnand.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/reset.h>
>> +
>> +#define COMMAND                                     0x00
>> +#define   COMMAND_GO                                BIT(31)
>> +#define   COMMAND_CLE                               BIT(30)
>> +#define   COMMAND_ALE                               BIT(29)
>> +#define   COMMAND_PIO                               BIT(28)
>> +#define   COMMAND_TX                                BIT(27)
>> +#define   COMMAND_RX                                BIT(26)
>> +#define   COMMAND_SEC_CMD                   BIT(25)
>> +#define   COMMAND_AFT_DAT                   BIT(24)
>> +#define   COMMAND_TRANS_SIZE(x)                     (((x - 1) & 0xf) << 20)
>> +#define   COMMAND_A_VALID                   BIT(19)
>> +#define   COMMAND_B_VALID                   BIT(18)
>> +#define   COMMAND_RD_STATUS_CHK                     BIT(17)
>> +#define   COMMAND_RBSY_CHK                  BIT(16)
>> +#define   COMMAND_CE(x)                             BIT(8 + ((x) & 0x7))
>> +#define   COMMAND_CLE_SIZE(x)                       (((x - 1) & 0x3) << 4)
>> +#define   COMMAND_ALE_SIZE(x)                       (((x - 1) & 0xf) << 0)
>> +
>> +#define STATUS                                      0x04
>> +
>> +#define ISR                                 0x08
>> +#define   ISR_CORRFAIL_ERR                  BIT(24)
>> +#define   ISR_UND                           BIT(7)
>> +#define   ISR_OVR                           BIT(6)
>> +#define   ISR_CMD_DONE                              BIT(5)
>> +#define   ISR_ECC_ERR                               BIT(4)
>> +
>> +#define IER                                 0x0c
>> +#define   IER_ERR_TRIG_VAL(x)                       (((x) & 0xf) << 16)
>> +#define   IER_UND                           BIT(7)
>> +#define   IER_OVR                           BIT(6)
>> +#define   IER_CMD_DONE                              BIT(5)
>> +#define   IER_ECC_ERR                               BIT(4)
>> +#define   IER_GIE                           BIT(0)
>> +
>> +#define CONFIG                                      0x10
>> +#define   CONFIG_HW_ECC                             BIT(31)
>> +#define   CONFIG_ECC_SEL                    BIT(30)
>> +#define   CONFIG_ERR_COR                    BIT(29)
>> +#define   CONFIG_PIPE_EN                    BIT(28)
>> +#define   CONFIG_TVAL_4                             (0 << 24)
>> +#define   CONFIG_TVAL_6                             (1 << 24)
>> +#define   CONFIG_TVAL_8                             (2 << 24)
>> +#define   CONFIG_SKIP_SPARE                 BIT(23)
>> +#define   CONFIG_BUS_WIDTH_16                       BIT(21)
>> +#define   CONFIG_COM_BSY                    BIT(20)
>> +#define   CONFIG_PS_256                             (0 << 16)
>> +#define   CONFIG_PS_512                             (1 << 16)
>> +#define   CONFIG_PS_1024                    (2 << 16)
>> +#define   CONFIG_PS_2048                    (3 << 16)
>> +#define   CONFIG_PS_4096                    (4 << 16)
>> +#define   CONFIG_SKIP_SPARE_SIZE_4          (0 << 14)
>> +#define   CONFIG_SKIP_SPARE_SIZE_8          (1 << 14)
>> +#define   CONFIG_SKIP_SPARE_SIZE_12         (2 << 14)
>> +#define   CONFIG_SKIP_SPARE_SIZE_16         (3 << 14)
>> +#define   CONFIG_TAG_BYTE_SIZE(x)                   ((x) & 0xff)
>> +
>> +#define TIMING_1                            0x14
>> +#define   TIMING_TRP_RESP(x)                        (((x) & 0xf) << 28)
>> +#define   TIMING_TWB(x)                             (((x) & 0xf) << 24)
>> +#define   TIMING_TCR_TAR_TRR(x)                     (((x) & 0xf) << 20)
>> +#define   TIMING_TWHR(x)                    (((x) & 0xf) << 16)
>> +#define   TIMING_TCS(x)                             (((x) & 0x3) << 14)
>> +#define   TIMING_TWH(x)                             (((x) & 0x3) << 12)
>> +#define   TIMING_TWP(x)                             (((x) & 0xf) <<  8)
>> +#define   TIMING_TRH(x)                             (((x) & 0x3) <<  4)
>> +#define   TIMING_TRP(x)                             (((x) & 0xf) <<  0)
>> +
>> +#define RESP                                        0x18
>> +
>> +#define TIMING_2                            0x1c
>> +#define   TIMING_TADL(x)                    ((x) & 0xf)
>> +
>> +#define CMD_REG1                            0x20
>> +#define CMD_REG2                            0x24
>> +#define ADDR_REG1                           0x28
>> +#define ADDR_REG2                           0x2c
>> +
>> +#define DMA_MST_CTRL                                0x30
>> +#define   DMA_MST_CTRL_GO                   BIT(31)
>> +#define   DMA_MST_CTRL_IN                   (0 << 30)
>> +#define   DMA_MST_CTRL_OUT                  BIT(30)
>> +#define   DMA_MST_CTRL_PERF_EN                      BIT(29)
>> +#define   DMA_MST_CTRL_IE_DONE                      BIT(28)
>> +#define   DMA_MST_CTRL_REUSE                        BIT(27)
>> +#define   DMA_MST_CTRL_BURST_1                      (2 << 24)
>> +#define   DMA_MST_CTRL_BURST_4                      (3 << 24)
>> +#define   DMA_MST_CTRL_BURST_8                      (4 << 24)
>> +#define   DMA_MST_CTRL_BURST_16                     (5 << 24)
>> +#define   DMA_MST_CTRL_IS_DONE                      BIT(20)
>> +#define   DMA_MST_CTRL_EN_A                 BIT(2)
>> +#define   DMA_MST_CTRL_EN_B                 BIT(1)
>> +
>> +#define DMA_CFG_A                           0x34
>> +#define DMA_CFG_B                           0x38
>> +
>> +#define FIFO_CTRL                           0x3c
>> +#define   FIFO_CTRL_CLR_ALL                 BIT(3)
>> +
>> +#define DATA_PTR                            0x40
>> +#define TAG_PTR                                     0x44
>> +#define ECC_PTR                                     0x48
>> +
>> +#define DEC_STATUS                          0x4c
>> +#define   DEC_STATUS_A_ECC_FAIL                     BIT(1)
>> +#define   DEC_STATUS_ERR_COUNT_MASK         0x00ff0000
>> +#define   DEC_STATUS_ERR_COUNT_SHIFT                16
>> +
>> +#define HWSTATUS_CMD                                0x50
>> +#define HWSTATUS_MASK                               0x54
>> +#define   HWSTATUS_RDSTATUS_MASK(x)         (((x) & 0xff) << 24)
>> +#define   HWSTATUS_RDSTATUS_VALUE(x)                (((x) & 0xff) << 16)
>> +#define   HWSTATUS_RBSY_MASK(x)                     (((x) & 0xff) << 8)
>> +#define   HWSTATUS_RBSY_VALUE(x)            (((x) & 0xff) << 0)
>> +
>> +#define BCH_CONFIG                          0xcc
>> +#define   BCH_ENABLE                                BIT(0)
>> +#define   BCH_TVAL_4                                (0 << 4)
>> +#define   BCH_TVAL_8                                (1 << 4)
>> +#define   BCH_TVAL_14                               (2 << 4)
>> +#define   BCH_TVAL_16                               (3 << 4)
>> +
>> +#define DEC_STAT_RESULT                             0xd0
>> +#define DEC_STAT_BUF                                0xd4
>> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_MASK   0xff000000
>> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT  24
>> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_MASK   0x00ff0000
>> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT  16
>> +#define   DEC_STAT_BUF_MAX_CORR_CNT_MASK    0x00001f00
>> +#define   DEC_STAT_BUF_MAX_CORR_CNT_SHIFT   8
>> +
>> +#define OFFSET(val, off)    ((val) < (off) ? 0 : (val) - (off))
>> +
>> +#define SKIP_SPARE_BYTES    4
>> +#define BITS_PER_STEP_RS    18
>> +#define BITS_PER_STEP_BCH   13
>> +
>> +#define INT_MASK            (IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE)
>> +#define HWSTATUS_CMD_DEFAULT        NAND_STATUS_READY
>> +#define HWSTATUS_MASK_DEFAULT       (HWSTATUS_RDSTATUS_MASK(1) | \
>> +                            HWSTATUS_RDSTATUS_VALUE(0) | \
>> +                            HWSTATUS_RBSY_MASK(NAND_STATUS_READY) | \
>> +                            HWSTATUS_RBSY_VALUE(NAND_STATUS_READY))
>> +
>> +struct tegra_nand_controller {
>> +    struct nand_hw_control controller;
>> +    struct device *dev;
>> +    void __iomem *regs;
>> +    int irq;
>> +    struct clk *clk;
>> +    struct completion command_complete;
>> +    struct completion dma_complete;
>> +    bool last_read_error;
>> +    int cur_cs;
>> +    struct nand_chip *chip;
>> +};
>> +
>> +struct tegra_nand_chip {
>> +    struct nand_chip chip;
>> +    struct gpio_desc *wp_gpio;
>> +    struct mtd_oob_region tag;
>> +    u32 config;
>> +    u32 config_ecc;
>> +    u32 bch_config;
>> +    int cs[1];
>> +};
>> +
>> +static inline struct tegra_nand_controller *to_tegra_ctrl(
>> +                                            struct nand_hw_control *hw_ctrl)
>> +{
>> +    return container_of(hw_ctrl, struct tegra_nand_controller, controller);
>> +}
>> +
>> +static inline struct tegra_nand_chip *to_tegra_chip(struct nand_chip *chip)
>> +{
>> +    return container_of(chip, struct tegra_nand_chip, chip);
>> +}
>> +
>> +static int tegra_nand_ooblayout_rs_ecc(struct mtd_info *mtd, int section,
>> +                                   struct mtd_oob_region *oobregion)
>> +{
>> +    struct nand_chip *chip = mtd_to_nand(mtd);
>> +    int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS * chip->ecc.strength,
>> +                                      BITS_PER_BYTE);
>> +
>> +    if (section > 0)
>> +            return -ERANGE;
>> +
>> +    oobregion->offset = SKIP_SPARE_BYTES;
>> +    oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
>> +
>> +    return 0;
>> +}
>> +
>> +static int tegra_nand_ooblayout_rs_free(struct mtd_info *mtd, int section,
>> +                                    struct mtd_oob_region *oobregion)
>> +{
>> +    struct nand_chip *chip = mtd_to_nand(mtd);
>> +    int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS * chip->ecc.strength,
>> +                                      BITS_PER_BYTE);
>> +
>> +    if (section > 0)
>> +            return -ERANGE;
>> +
>> +    oobregion->offset = SKIP_SPARE_BYTES +
>> +                        round_up(bytes_per_step * chip->ecc.steps, 4);
>> +    oobregion->length = mtd->oobsize - oobregion->offset;
>> +
>> +    return 0;
>> +}
>> +
>> +static const struct mtd_ooblayout_ops tegra_nand_oob_rs_ops = {
>> +    .ecc = tegra_nand_ooblayout_rs_ecc,
>> +    .free = tegra_nand_ooblayout_rs_free,
>> +};
>> +
>> +static int tegra_nand_ooblayout_bch_ecc(struct mtd_info *mtd, int section,
>> +                                   struct mtd_oob_region *oobregion)
>> +{
>> +    struct nand_chip *chip = mtd_to_nand(mtd);
>> +    int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * 
>> chip->ecc.strength,
>> +                                      BITS_PER_BYTE);
>> +
>> +    if (section > 0)
>> +            return -ERANGE;
>> +
>> +    oobregion->offset = SKIP_SPARE_BYTES;
>> +    oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
>> +
>> +    return 0;
>> +}
>> +
>> +static int tegra_nand_ooblayout_bch_free(struct mtd_info *mtd, int section,
>> +                                    struct mtd_oob_region *oobregion)
>> +{
>> +    struct nand_chip *chip = mtd_to_nand(mtd);
>> +    int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * 
>> chip->ecc.strength,
>> +                                      BITS_PER_BYTE);
>> +
>> +    if (section > 0)
>> +            return -ERANGE;
>> +
>> +    oobregion->offset = SKIP_SPARE_BYTES +
>> +                        round_up(bytes_per_step * chip->ecc.steps, 4);
>> +    oobregion->length = mtd->oobsize - oobregion->offset;
>> +
>> +    return 0;
>> +}
>> +
>> +/*
>> + * Layout with tag bytes is
>> + *
>> + *
>> --------------------------------------------------------------------------
>> + * | main area                       | skip bytes | tag bytes | parity |
>> .. | + *
>> --------------------------------------------------------------------------
>> + *
>> + * If not tag bytes are written, parity moves right after skip bytes!
>> + */
>> +static const struct mtd_ooblayout_ops tegra_nand_oob_bch_ops = {
>> +    .ecc = tegra_nand_ooblayout_bch_ecc,
>> +    .free = tegra_nand_ooblayout_bch_free,
>> +};
>> +
>> +static irqreturn_t tegra_nand_irq(int irq, void *data)
>> +{
>> +    struct tegra_nand_controller *ctrl = data;
>> +    u32 isr, dma;
>> +
>> +    isr = readl_relaxed(ctrl->regs + ISR);
>> +    dma = readl_relaxed(ctrl->regs + DMA_MST_CTRL);
>> +    dev_dbg(ctrl->dev, "isr %08x\n", isr);
>> +
>> +    if (!isr && !(dma & DMA_MST_CTRL_IS_DONE))
>> +            return IRQ_NONE;
>> +
>> +    /*
>> +     * The bit name is somewhat missleading: This is also set when
>> +     * HW ECC was successful. The data sheet states:
>> +     * Correctable OR Un-correctable errors occurred in the DMA transfer...
>> +     */
>> +    if (isr & ISR_CORRFAIL_ERR)
>> +            ctrl->last_read_error = true;
>> +
>> +    if (isr & ISR_CMD_DONE)
>> +            complete(&ctrl->command_complete);
>> +
>> +    if (isr & ISR_UND)
>> +            dev_err(ctrl->dev, "FIFO underrun\n");
>> +
>> +    if (isr & ISR_OVR)
>> +            dev_err(ctrl->dev, "FIFO overrun\n");
>> +
>> +    /* handle DMA interrupts */
>> +    if (dma & DMA_MST_CTRL_IS_DONE) {
>> +            writel_relaxed(dma, ctrl->regs + DMA_MST_CTRL);
>> +            complete(&ctrl->dma_complete);
>> +    }
>> +
>> +    /* clear interrupts */
>> +    writel_relaxed(isr, ctrl->regs + ISR);
>> +
>> +    return IRQ_HANDLED;
>> +}
>> +
>> +static const char * const tegra_nand_reg_names[] = {
>> +    "COMMAND",
>> +    "STATUS",
>> +    "ISR",
>> +    "IER",
>> +    "CONFIG",
>> +    "TIMING",
>> +    NULL,
>> +    "TIMING2",
>> +    "CMD_REG1",
>> +    "CMD_REG2",
>> +    "ADDR_REG1",
>> +    "ADDR_REG2",
>> +    "DMA_MST_CTRL",
>> +    "DMA_CFG_A",
>> +    "DMA_CFG_B",
>> +    "FIFO_CTRL",
>> +};
>> +
>> +static void tegra_nand_dump_reg(struct tegra_nand_controller *ctrl)
>> +{
>> +    u32 reg;
>> +    int i;
>> +
>> +    dev_err(ctrl->dev, "Tegra NAND controller register dump\n");
>> +    for (i = 0; i < ARRAY_SIZE(tegra_nand_reg_names); i++) {
>> +            const char *reg_name = tegra_nand_reg_names[i];
>> +
>> +            if (!reg_name)
>> +                    continue;
>> +
>> +            reg = readl_relaxed(ctrl->regs + (i * 4));
>> +            dev_err(ctrl->dev, "%s: 0x%08x\n", reg_name, reg);
>> +    }
>> +}
>> +
>> +static void tegra_nand_controller_abort(struct tegra_nand_controller *ctrl)
>> +{
>> +    u32 isr, dma;
>> +
>> +    disable_irq(ctrl->irq);
>> +
>> +    /* Abort current command/DMA operation */
>> +    writel_relaxed(0, ctrl->regs + DMA_MST_CTRL);
>> +    writel_relaxed(0, ctrl->regs + COMMAND);
>> +
>> +    /* clear interrupts */
>> +    isr = readl_relaxed(ctrl->regs + ISR);
>> +    writel_relaxed(isr, ctrl->regs + ISR);
>> +    dma = readl_relaxed(ctrl->regs + DMA_MST_CTRL);
>> +    writel_relaxed(dma, ctrl->regs + DMA_MST_CTRL);
>> +
>> +    reinit_completion(&ctrl->command_complete);
>> +    reinit_completion(&ctrl->dma_complete);
>> +
>> +    enable_irq(ctrl->irq);
>> +}
>> +
>> +static int tegra_nand_cmd(struct nand_chip *chip,
>> +                     const struct nand_subop *subop)
>> +{
>> +    const struct nand_op_instr *instr;
>> +    const struct nand_op_instr *instr_data_in = NULL;
>> +    struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +    unsigned int op_id, size = 0, offset = 0;
>> +    bool first_cmd = true;
>> +    u32 reg, cmd = 0;
>> +    int ret;
>> +
>> +    for (op_id = 0; op_id < subop->ninstrs; op_id++) {
>> +            unsigned int naddrs, i;
>> +            const u8 *addrs;
>> +            u32 addr1 = 0, addr2 = 0;
>> +
>> +            instr = &subop->instrs[op_id];
>> +
>> +            switch (instr->type) {
>> +            case NAND_OP_CMD_INSTR:
>> +                    if (first_cmd) {
>> +                            cmd |= COMMAND_CLE;
>> +                            writel_relaxed(instr->ctx.cmd.opcode,
>> +                                           ctrl->regs + CMD_REG1);
>> +                    } else {
>> +                            cmd |= COMMAND_SEC_CMD;
>> +                            writel_relaxed(instr->ctx.cmd.opcode,
>> +                                           ctrl->regs + CMD_REG2);
>> +                    }
>> +                    first_cmd = false;
>> +                    break;
> 
> Newline here.
> 
>> +            case NAND_OP_ADDR_INSTR:
>> +                    offset = nand_subop_get_addr_start_off(subop, op_id);
>> +                    naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
>> +                    addrs = &instr->ctx.addr.addrs[offset];
>> +
>> +                    cmd |= COMMAND_ALE | COMMAND_ALE_SIZE(naddrs);
>> +                    for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
>> +                            addr1 |= *addrs++ << (BITS_PER_BYTE * i);
>> +                    naddrs -= i;
>> +                    for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
>> +                            addr2 |= *addrs++ << (BITS_PER_BYTE * i);
>> +                    writel_relaxed(addr1, ctrl->regs + ADDR_REG1);
>> +                    writel_relaxed(addr2, ctrl->regs + ADDR_REG2);
>> +                    break;
>> +
>> +            case NAND_OP_DATA_IN_INSTR:
>> +                    size = nand_subop_get_data_len(subop, op_id);
>> +                    offset = nand_subop_get_data_start_off(subop, op_id);
>> +
>> +                    cmd |= COMMAND_TRANS_SIZE(size) | COMMAND_PIO |
>> +                            COMMAND_RX | COMMAND_A_VALID;
>> +
>> +                    instr_data_in = instr;
>> +                    break;
>> +
>> +            case NAND_OP_DATA_OUT_INSTR:
>> +                    size = nand_subop_get_data_len(subop, op_id);
>> +                    offset = nand_subop_get_data_start_off(subop, op_id);
>> +
>> +                    cmd |= COMMAND_TRANS_SIZE(size) | COMMAND_PIO |
>> +                            COMMAND_TX | COMMAND_A_VALID;
>> +
>> +                    memcpy(&reg, instr->ctx.data.buf.out + offset, size);
>> +                    writel_relaxed(reg, ctrl->regs + RESP);
>> +
>> +                    break;
> 
> Newline here.
> 
>> +            case NAND_OP_WAITRDY_INSTR:
>> +                    cmd |= COMMAND_RBSY_CHK;
>> +                    break;
>> +
> 
> Blank line isn't needed here.
> 
>> +            }
>> +    }
>> +
>> +    cmd |= COMMAND_GO | COMMAND_CE(ctrl->cur_cs);
>> +    writel_relaxed(cmd, ctrl->regs + COMMAND);
>> +    ret = wait_for_completion_io_timeout(&ctrl->command_complete,
>> +                                         msecs_to_jiffies(500));
>> +    if (!ret) {
>> +            dev_err(ctrl->dev, "COMMAND timeout\n");
>> +            tegra_nand_dump_reg(ctrl);
>> +            tegra_nand_controller_abort(ctrl);
>> +            return -ETIMEDOUT;
>> +    }
>> +
>> +    if (instr_data_in) {
>> +            reg = readl_relaxed(ctrl->regs + RESP);
>> +            memcpy(instr_data_in->ctx.data.buf.in + offset, &reg, size);
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static const struct nand_op_parser tegra_nand_op_parser = NAND_OP_PARSER(
>> +    NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
>> +            NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> +            NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
>> +            NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> +            NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
>> +    NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
>> +            NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, 4)),
>> +    NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
>> +            NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> +            NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
>> +            NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> +            NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
>> +            NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, 4)),
>> +    );
>> +
>> +static int tegra_nand_exec_op(struct nand_chip *chip,
>> +                         const struct nand_operation *op,
>> +                         bool check_only)
>> +{
>> +    return nand_op_parser_exec_op(chip, &tegra_nand_op_parser, op,
>> +                                  check_only);
>> +}
> 
> Newline here.
> 
>> +static void tegra_nand_select_chip(struct mtd_info *mtd, int die_nr)
>> +{
>> +    struct nand_chip *chip = mtd_to_nand(mtd);
>> +    struct tegra_nand_chip *nand = to_tegra_chip(chip);
>> +    struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +
>> +    if (die_nr < 0 || die_nr > 1) {
>> +            ctrl->cur_cs = -1;
>> +            return;
>> +    }
>> +
>> +    ctrl->cur_cs = nand->cs[die_nr];
>> +}
>> +
>> +static void tegra_nand_hw_ecc(struct tegra_nand_controller *ctrl,
>> +                          struct nand_chip *chip, bool enable)
>> +{
>> +    struct tegra_nand_chip *nand = to_tegra_chip(chip);
>> +
>> +    if (chip->ecc.algo == NAND_ECC_BCH && enable)
>> +            writel_relaxed(nand->bch_config, ctrl->regs + BCH_CONFIG);
>> +    else
>> +            writel_relaxed(0, ctrl->regs + BCH_CONFIG);
>> +
>> +    if (enable)
>> +            writel_relaxed(nand->config_ecc, ctrl->regs + CONFIG);
>> +    else
>> +            writel_relaxed(nand->config, ctrl->regs + CONFIG);
>> +}
>> +
>> +static int tegra_nand_page_xfer(struct mtd_info *mtd, struct nand_chip
>> *chip, +                             void *buf, void *oob_buf, int oob_len, 
>> int page,
>> +                            bool read)
>> +{
>> +    struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +    enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
>> +    dma_addr_t dma_addr = 0, dma_addr_oob = 0;
>> +    u32 addr1, cmd, dma_ctrl;
>> +    int ret;
>> +
>> +    if (read) {
>> +            writel_relaxed(NAND_CMD_READ0, ctrl->regs + CMD_REG1);
>> +            writel_relaxed(NAND_CMD_READSTART, ctrl->regs + CMD_REG2);
>> +    } else {
>> +            writel_relaxed(NAND_CMD_SEQIN, ctrl->regs + CMD_REG1);
>> +            writel_relaxed(NAND_CMD_PAGEPROG, ctrl->regs + CMD_REG2);
>> +    }
>> +    cmd = COMMAND_CLE | COMMAND_SEC_CMD;
>> +
>> +    /* Lower 16-bits are column, by default 0 */
>> +    addr1 = page << 16;
>> +
>> +    if (!buf)
>> +            addr1 |= mtd->writesize;
>> +    writel_relaxed(addr1, ctrl->regs + ADDR_REG1);
>> +
>> +    if (chip->options & NAND_ROW_ADDR_3) {
>> +            writel_relaxed(page >> 16, ctrl->regs + ADDR_REG2);
>> +            cmd |= COMMAND_ALE | COMMAND_ALE_SIZE(5);
>> +    } else {
>> +            cmd |= COMMAND_ALE | COMMAND_ALE_SIZE(4);
>> +    }
>> +
>> +    if (buf) {
>> +            dma_addr = dma_map_single(ctrl->dev, buf, mtd->writesize, dir);
>> +            ret = dma_mapping_error(ctrl->dev, dma_addr);
>> +            if (ret) {
>> +                    dev_err(ctrl->dev, "dma mapping error\n");
>> +                    return -EINVAL;
>> +            }
>> +
>> +            writel_relaxed(mtd->writesize - 1, ctrl->regs + DMA_CFG_A);
>> +            writel_relaxed(dma_addr, ctrl->regs + DATA_PTR);
>> +    }
>> +
>> +    if (oob_buf) {
>> +            dma_addr_oob = dma_map_single(ctrl->dev, oob_buf, mtd->oobsize,
>> +                                          dir);
>> +            ret = dma_mapping_error(ctrl->dev, dma_addr_oob);
>> +            if (ret) {
>> +                    dev_err(ctrl->dev, "dma mapping error\n");
>> +                    ret = -EINVAL;
>> +                    goto err_unmap_dma_page;
>> +            }
>> +
>> +            writel_relaxed(oob_len - 1, ctrl->regs + DMA_CFG_B);
>> +            writel_relaxed(dma_addr_oob, ctrl->regs + TAG_PTR);
>> +    }
>> +
>> +    dma_ctrl = DMA_MST_CTRL_GO | DMA_MST_CTRL_PERF_EN |
>> +               DMA_MST_CTRL_IE_DONE | DMA_MST_CTRL_IS_DONE |
>> +               DMA_MST_CTRL_BURST_16;
>> +
>> +    if (buf)
>> +            dma_ctrl |= DMA_MST_CTRL_EN_A;
>> +    if (oob_buf)
>> +            dma_ctrl |= DMA_MST_CTRL_EN_B;
>> +
>> +    if (read)
>> +            dma_ctrl |= DMA_MST_CTRL_IN | DMA_MST_CTRL_REUSE;
>> +    else
>> +            dma_ctrl |= DMA_MST_CTRL_OUT;
>> +
>> +    writel_relaxed(dma_ctrl, ctrl->regs + DMA_MST_CTRL);
>> +
>> +    cmd |= COMMAND_GO | COMMAND_RBSY_CHK | COMMAND_TRANS_SIZE(9) |
>> +           COMMAND_CE(ctrl->cur_cs);
>> +
>> +    if (buf)
>> +            cmd |= COMMAND_A_VALID;
>> +    if (oob_buf)
>> +            cmd |= COMMAND_B_VALID;
>> +
>> +    if (read)
>> +            cmd |= COMMAND_RX;
>> +    else
>> +            cmd |= COMMAND_TX | COMMAND_AFT_DAT;
>> +
>> +    writel_relaxed(cmd, ctrl->regs + COMMAND);
>> +
>> +    ret = wait_for_completion_io_timeout(&ctrl->command_complete,
>> +                                         msecs_to_jiffies(500));
>> +    if (!ret) {
>> +            dev_err(ctrl->dev, "COMMAND timeout\n");
>> +            tegra_nand_dump_reg(ctrl);
>> +            tegra_nand_controller_abort(ctrl);
>> +            ret = -ETIMEDOUT;
>> +            goto err_unmap_dma;
>> +    }
>> +
>> +    ret = wait_for_completion_io_timeout(&ctrl->dma_complete,
>> +                                         msecs_to_jiffies(500));
>> +    if (!ret) {
>> +            dev_err(ctrl->dev, "DMA timeout\n");
>> +            tegra_nand_dump_reg(ctrl);
>> +            tegra_nand_controller_abort(ctrl);
>> +            ret = -ETIMEDOUT;
>> +            goto err_unmap_dma;
>> +    }
>> +    ret = 0;
>> +
>> +err_unmap_dma:
>> +    if (oob_buf)
>> +            dma_unmap_single(ctrl->dev, dma_addr_oob, mtd->oobsize, dir);
>> +err_unmap_dma_page:
>> +    if (buf)
>> +            dma_unmap_single(ctrl->dev, dma_addr, mtd->writesize, dir);
>> +
>> +    return ret;
>> +}
>> +
>> +static int tegra_nand_read_page_raw(struct mtd_info *mtd,
>> +                                struct nand_chip *chip,
>> +                                uint8_t *buf, int oob_required, int page)
>> +{
>> +    void *oob_buf = oob_required ? chip->oob_poi : 0;
>> +
>> +    return tegra_nand_page_xfer(mtd, chip, buf, oob_buf,
>> +                                mtd->oobsize, page, true);
>> +}
>> +
>> +static int tegra_nand_write_page_raw(struct mtd_info *mtd,
>> +                                 struct nand_chip *chip,
>> +                                 const uint8_t *buf, int oob_required,
>> +                                 int page)
>> +{
>> +    void *oob_buf = oob_required ? chip->oob_poi : 0;
>> +
>> +    return tegra_nand_page_xfer(mtd, chip, (void *)buf, oob_buf,
>> +                                 mtd->oobsize, page, false);
>> +}
>> +
>> +static int tegra_nand_read_oob(struct mtd_info *mtd, struct nand_chip
>> *chip, +                            int page)
>> +{
>> +    return tegra_nand_page_xfer(mtd, chip, NULL, chip->oob_poi,
>> +                                mtd->oobsize, page, true);
>> +}
>> +
>> +static int tegra_nand_write_oob(struct mtd_info *mtd, struct nand_chip
>> *chip, +                             int page)
>> +{
>> +    return tegra_nand_page_xfer(mtd, chip, NULL, chip->oob_poi,
>> +                                mtd->oobsize, page, false);
>> +}
>> +
>> +static int tegra_nand_read_page_hwecc(struct mtd_info *mtd,
>> +                                  struct nand_chip *chip,
>> +                                  uint8_t *buf, int oob_required, int page)
>> +{
>> +    struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +    struct tegra_nand_chip *nand = to_tegra_chip(chip);
>> +    void *oob_buf = oob_required ? chip->oob_poi : 0;
>> +    u32 dec_stat, max_corr_cnt;
>> +    unsigned long fail_sec_flag;
>> +    int ret;
>> +
>> +    tegra_nand_hw_ecc(ctrl, chip, true);
>> +    ret = tegra_nand_page_xfer(mtd, chip, buf, oob_buf, nand->tag.length,
>> +                               page, true);
>> +    tegra_nand_hw_ecc(ctrl, chip, false);
>> +    if (ret)
>> +            return ret;
>> +
>> +    /* No correctable or un-correctable errors, page must have 0 bitflips */
>> +    if (!ctrl->last_read_error)
>> +            return 0;
>> +
>> +    /*
>> +     * Correctable or un-correctable errors occurred. Use DEC_STAT_BUF
>> +     * which contains information for all ECC selections.
>> +     *
>> +     * Note that since we do not use Command Queues DEC_RESULT does not
>> +     * state the number of pages we can read from the DEC_STAT_BUF. But
>> +     * since CORRFAIL_ERR did occur during page read we do have a valid
>> +     * result in DEC_STAT_BUF.
>> +     */
>> +    ctrl->last_read_error = false;
>> +    dec_stat = readl_relaxed(ctrl->regs + DEC_STAT_BUF);
>> +
>> +    fail_sec_flag = (dec_stat & DEC_STAT_BUF_FAIL_SEC_FLAG_MASK) >>
>> +                    DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT;
>> +
>> +    max_corr_cnt = (dec_stat & DEC_STAT_BUF_MAX_CORR_CNT_MASK) >>
>> +                   DEC_STAT_BUF_MAX_CORR_CNT_SHIFT;
>> +
>> +    if (fail_sec_flag) {
>> +            int bit, max_bitflips = 0;
>> +
>> +            /*
>> +             * Check if all sectors in a page failed. If only some failed
>> +             * its definitly not an erased page and we can return error
>> +             * stats right away.
>> +             *
>> +             * E.g. controller might return fail_sec_flag with 0x4, which
>> +             * would mean only the third sector failed to correct.
>> +             */
>> +            if (fail_sec_flag ^ GENMASK(chip->ecc.steps - 1, 0)) {
>> +                    mtd->ecc_stats.failed += hweight8(fail_sec_flag);
>> +                    return max_corr_cnt;
>> +            }
>> +
>> +            /*
>> +             * All sectors failed to correct, but the ECC isn't smart
>> +             * enough to figure out if a page is really completely erased.
>> +             * We check the read data here to figure out if it's a
>> +             * legitimate ECC error or only an erased page.
>> +             */
>> +            for_each_set_bit(bit, &fail_sec_flag, chip->ecc.steps) {
>> +                    u8 *data = buf + (chip->ecc.size * bit);
>> +
>> +                    ret = nand_check_erased_ecc_chunk(data, chip->ecc.size,
>> +                                                      NULL, 0,
>> +                                                      NULL, 0,
>> +                                                      chip->ecc.strength);
>> +                    if (ret < 0)
>> +                            mtd->ecc_stats.failed++;
>> +                    else
>> +                            max_bitflips = max(ret, max_bitflips);
>> +            }
>> +
>> +            return max_t(unsigned int, max_corr_cnt, max_bitflips);
>> +    } else {
>> +            int corr_sec_flag;
>> +
>> +            corr_sec_flag = (dec_stat & DEC_STAT_BUF_CORR_SEC_FLAG_MASK) >>
>> +                            DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT;
>> +
>> +            /*
>> +             * The value returned in the register is the maximum of
>> +             * bitflips encountered in any of the ECC regions. As there is
>> +             * no way to get the number of bitflips in a specific regions
>> +             * we are not able to deliver correct stats but instead
>> +             * overestimate the number of corrected bitflips by assuming
>> +             * that all regions where errors have been corrected
>> +             * encountered the maximum number of bitflips.
>> +             */
>> +            mtd->ecc_stats.corrected += max_corr_cnt * 
>> hweight8(corr_sec_flag);
>> +
>> +            return max_corr_cnt;
>> +    }
>> +
> 
> Blank line isn't needed here.
> 
>> +}
>> +
>> +static int tegra_nand_write_page_hwecc(struct mtd_info *mtd,
>> +                                   struct nand_chip *chip,
>> +                                   const uint8_t *buf, int oob_required,
>> +                                   int page)
>> +{
>> +    struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +    struct tegra_nand_chip *nand = to_tegra_chip(chip);
>> +    void *oob_buf = oob_required ? chip->oob_poi : 0;
>> +    int ret;
>> +
>> +    tegra_nand_hw_ecc(ctrl, chip, true);
>> +    ret = tegra_nand_page_xfer(mtd, chip, (void *)buf, oob_buf,
>> +                               nand->tag.length, page, false);
>> +    tegra_nand_hw_ecc(ctrl, chip, false);
>> +
>> +    return ret;
>> +}
>> +
>> +static void tegra_nand_setup_timing(struct tegra_nand_controller *ctrl,
>> +                                const struct nand_sdr_timings *timings)
>> +{
>> +    /*
>> +     * The period (and all other timings in this function) is in ps,
>> +     * so need to take care here to avoid integer overflows.
>> +     */
>> +    unsigned int rate = clk_get_rate(ctrl->clk) / 1000000;
>> +    unsigned int period = DIV_ROUND_UP(1000000, rate);
>> +    u32 val, reg = 0;
>> +
>> +    val = DIV_ROUND_UP(max3(timings->tAR_min, timings->tRR_min,
>> +                            timings->tRC_min), period);
>> +    reg |= TIMING_TCR_TAR_TRR(OFFSET(val, 3));
>> +
>> +    val = DIV_ROUND_UP(max(max(timings->tCS_min, timings->tCH_min),
>> +                           max(timings->tALS_min, timings->tALH_min)),
>> +                       period);
>> +    reg |= TIMING_TCS(OFFSET(val, 2));
>> +
>> +    val = DIV_ROUND_UP(max(timings->tRP_min, timings->tREA_max) + 6000,
>> +                       period);
>> +    reg |= TIMING_TRP(OFFSET(val, 1)) | TIMING_TRP_RESP(OFFSET(val, 1));
>> +
>> +    reg |= TIMING_TWB(OFFSET(DIV_ROUND_UP(timings->tWB_max, period), 1));
>> +    reg |= TIMING_TWHR(OFFSET(DIV_ROUND_UP(timings->tWHR_min, period), 1));
>> +    reg |= TIMING_TWH(OFFSET(DIV_ROUND_UP(timings->tWH_min, period), 1));
>> +    reg |= TIMING_TWP(OFFSET(DIV_ROUND_UP(timings->tWP_min, period), 1));
>> +    reg |= TIMING_TRH(OFFSET(DIV_ROUND_UP(timings->tREH_min, period), 1));
>> +
>> +    writel_relaxed(reg, ctrl->regs + TIMING_1);
>> +
>> +    val = DIV_ROUND_UP(timings->tADL_min, period);
>> +    reg = TIMING_TADL(OFFSET(val, 3));
>> +
>> +    writel_relaxed(reg, ctrl->regs + TIMING_2);
>> +}
>> +
>> +static int tegra_nand_setup_data_interface(struct mtd_info *mtd, int
>> csline, +                                    const struct 
>> nand_data_interface *conf)
>> +{
>> +    struct nand_chip *chip = mtd_to_nand(mtd);
>> +    struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +    const struct nand_sdr_timings *timings;
>> +
>> +    timings = nand_get_sdr_timings(conf);
>> +    if (IS_ERR(timings))
>> +            return PTR_ERR(timings);
>> +
>> +    if (csline == NAND_DATA_IFACE_CHECK_ONLY)
>> +            return 0;
>> +
>> +    tegra_nand_setup_timing(ctrl, timings);
>> +
>> +    return 0;
>> +}
>> +
>> +static const int rs_strength_bootable[] = { 4 };
>> +static const int rs_strength[] = { 4, 6, 8 };
>> +static const int bch_strength_bootable[] = { 8, 16 };
>> +static const int bch_strength[] = { 4, 8, 14, 16 };
>> +
>> +static int tegra_nand_get_strength(struct nand_chip *chip, const int
>> *strength, +                            int strength_len, int oobsize)
>> +{
>> +    bool maximize = chip->ecc.options & NAND_ECC_MAXIMIZE;
>> +    int i;
>> +
>> +    /*
>> +     * Loop through available strengths. Backwards in case we try to
>> +     * maximize the BCH strength.
>> +     */
>> +    for (i = 0; i < strength_len; i++) {
>> +            int strength_sel, bytes_per_step, bytes_per_page;
>> +
>> +            if (maximize) {
>> +                    strength_sel = strength[strength_len - i - 1];
>> +            } else {
>> +                    strength_sel = strength[i];
>> +
>> +                    if (strength_sel < chip->ecc_strength_ds)
>> +                            continue;
>> +            }
>> +
>> +            bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * strength_sel,
>> +                                          BITS_PER_BYTE);
>> +            bytes_per_page = round_up(bytes_per_step * chip->ecc.steps, 4);
>> +
>> +            /* Check whether strength fits OOB */
>> +            if (bytes_per_page < (oobsize - SKIP_SPARE_BYTES))
>> +                    return strength_sel;
>> +    }
>> +
>> +    return -EINVAL;
>> +}
>> +
>> +static int tegra_nand_select_strength(struct nand_chip *chip, int oobsize)
>> +{
>> +    const int *strength;
>> +    int strength_len;
>> +
>> +    switch (chip->ecc.algo) {
>> +    case NAND_ECC_RS:
>> +            if (chip->options & NAND_IS_BOOT_MEDIUM) {
>> +                    strength = rs_strength_bootable;
>> +                    strength_len = ARRAY_SIZE(rs_strength_bootable);
>> +            } else {
>> +                    strength = rs_strength;
>> +                    strength_len = ARRAY_SIZE(rs_strength);
>> +            }
>> +            break;
>> +    case NAND_ECC_BCH:
>> +            if (chip->options & NAND_IS_BOOT_MEDIUM) {
>> +                    strength = bch_strength_bootable;
>> +                    strength_len = ARRAY_SIZE(bch_strength_bootable);
>> +            } else {
>> +                    strength = bch_strength;
>> +                    strength_len = ARRAY_SIZE(bch_strength);
>> +            }
>> +            break;
>> +    default:
>> +            return -EINVAL;
>> +    }
>> +
>> +    return tegra_nand_get_strength(chip, strength, strength_len, oobsize);
>> +}
>> +
>> +static int tegra_nand_chips_init(struct device *dev,
>> +                             struct tegra_nand_controller *ctrl)
>> +{
>> +    struct device_node *np = dev->of_node;
>> +    struct device_node *np_nand;
>> +    int nsels, nchips = of_get_child_count(np);
>> +    struct tegra_nand_chip *nand;
>> +    struct mtd_info *mtd;
>> +    struct nand_chip *chip;
>> +    int bits_per_step;
>> +    int ret;
>> +    u32 cs;
>> +
>> +    if (nchips != 1) {
>> +            dev_err(dev, "Currently only one NAND chip supported\n");
>> +            return -EINVAL;
>> +    }
>> +
>> +    np_nand = of_get_next_child(np, NULL);
>> +
>> +    nsels = of_property_count_elems_of_size(np_nand, "reg", sizeof(u32));
>> +    if (nsels != 1) {
>> +            dev_err(dev, "Missing/invalid reg property\n");
>> +            return -EINVAL;
>> +    }
>> +
>> +    /* Retrieve CS id, currently only single die NAND supported */
>> +    ret = of_property_read_u32(np_nand, "reg", &cs);
>> +    if (ret) {
>> +            dev_err(dev, "could not retrieve reg property: %d\n", ret);
>> +            return ret;
>> +    }
>> +
>> +    nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
>> +    if (!nand)
>> +            return -ENOMEM;
>> +
>> +    nand->cs[0] = cs;
>> +
>> +    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;
>> +    chip->controller = &ctrl->controller;
>> +
>> +    mtd = nand_to_mtd(chip);
>> +
>> +    mtd->dev.parent = dev;
>> +    mtd->owner = THIS_MODULE;
>> +
>> +    nand_set_flash_node(chip, np_nand);
>> +
>> +    if (!mtd->name)
>> +            mtd->name = "tegra_nand";
>> +
>> +    chip->options = NAND_NO_SUBPAGE_WRITE | NAND_USE_BOUNCE_BUFFER;
>> +    chip->exec_op = tegra_nand_exec_op;
>> +    chip->select_chip = tegra_nand_select_chip;
>> +    chip->setup_data_interface = tegra_nand_setup_data_interface;
>> +
>> +    ret = nand_scan_ident(mtd, 1, NULL);
>> +    if (ret)
>> +            return ret;
>> +
>> +    if (chip->bbt_options & NAND_BBT_USE_FLASH)
>> +            chip->bbt_options |= NAND_BBT_NO_OOB;
>> +
>> +    chip->ecc.mode = NAND_ECC_HW;
>> +    chip->ecc.size = 512;
>> +    chip->ecc.steps = mtd->writesize / chip->ecc.size;
>> +    if (chip->ecc_step_ds != 512) {
>> +            dev_err(dev, "Unsupported step size %d\n", chip->ecc_step_ds);
>> +            return -EINVAL;
>> +    }
>> +
>> +    chip->ecc.read_page = tegra_nand_read_page_hwecc;
>> +    chip->ecc.write_page = tegra_nand_write_page_hwecc;
>> +    chip->ecc.read_page_raw = tegra_nand_read_page_raw;
>> +    chip->ecc.write_page_raw = tegra_nand_write_page_raw;
>> +    chip->ecc.read_oob = tegra_nand_read_oob;
>> +    chip->ecc.write_oob = tegra_nand_write_oob;
>> +
>> +    if (chip->options & NAND_BUSWIDTH_16)
>> +            nand->config |= CONFIG_BUS_WIDTH_16;
>> +
>> +    if (chip->ecc.algo == NAND_ECC_UNKNOWN) {
>> +            if (mtd->writesize < 2048)
>> +                    chip->ecc.algo = NAND_ECC_RS;
>> +            else
>> +                    chip->ecc.algo = NAND_ECC_BCH;
>> +    }
>> +
>> +    if (chip->ecc.algo == NAND_ECC_BCH && mtd->writesize < 2048) {
>> +            dev_err(dev, "BCH supportes 2K or 4K page size only\n");
>> +            return -EINVAL;
>> +    }
>> +
>> +    if (!chip->ecc.strength) {
>> +            ret = tegra_nand_select_strength(chip, mtd->oobsize);
>> +            if (ret < 0) {
>> +                    dev_err(dev, "No valid strenght found, minimum %d\n",
>> +                            chip->ecc_strength_ds);
>> +                    return ret;
>> +            }
>> +
>> +            chip->ecc.strength = ret;
>> +    }
>> +
>> +    nand->config_ecc = CONFIG_PIPE_EN | CONFIG_SKIP_SPARE |
>> +                       CONFIG_SKIP_SPARE_SIZE_4;
>> +
>> +    switch (chip->ecc.algo) {
>> +    case NAND_ECC_RS:
>> +            bits_per_step = BITS_PER_STEP_RS * chip->ecc.strength;
>> +            mtd_set_ooblayout(mtd, &tegra_nand_oob_rs_ops);
>> +            nand->config_ecc |= CONFIG_HW_ECC | CONFIG_ECC_SEL |
>> +                                CONFIG_ERR_COR;
>> +            switch (chip->ecc.strength) {
>> +            case 4:
>> +                    nand->config_ecc |= CONFIG_TVAL_4;
>> +                    break;
>> +            case 6:
>> +                    nand->config_ecc |= CONFIG_TVAL_6;
>> +                    break;
>> +            case 8:
>> +                    nand->config_ecc |= CONFIG_TVAL_8;
>> +                    break;
>> +            default:
>> +                    dev_err(dev, "ECC strength %d not supported\n",
>> +                            chip->ecc.strength);
>> +                    return -EINVAL;
>> +            }
>> +            break;
>> +    case NAND_ECC_BCH:
>> +            bits_per_step = BITS_PER_STEP_BCH * chip->ecc.strength;
>> +            mtd_set_ooblayout(mtd, &tegra_nand_oob_bch_ops);
>> +            nand->bch_config = BCH_ENABLE;
>> +            switch (chip->ecc.strength) {
>> +            case 4:
>> +                    nand->bch_config |= BCH_TVAL_4;
>> +                    break;
>> +            case 8:
>> +                    nand->bch_config |= BCH_TVAL_8;
>> +                    break;
>> +            case 14:
>> +                    nand->bch_config |= BCH_TVAL_14;
>> +                    break;
>> +            case 16:
>> +                    nand->bch_config |= BCH_TVAL_16;
>> +                    break;
>> +            default:
>> +                    dev_err(dev, "ECC strength %d not supported\n",
>> +                            chip->ecc.strength);
>> +                    return -EINVAL;
>> +            }
>> +            break;
>> +    default:
>> +            dev_err(dev, "ECC algorithm not supported\n");
>> +            return -EINVAL;
>> +    }
>> +
>> +    dev_info(dev, "Using %s with strength %d per 512 byte step\n",
>> +                    chip->ecc.algo == NAND_ECC_BCH ? "BCH" : "RS",
>> +                    chip->ecc.strength);
>> +
>> +    chip->ecc.bytes = DIV_ROUND_UP(bits_per_step, BITS_PER_BYTE);
>> +
>> +    switch (mtd->writesize) {
>> +    case 256:
>> +            nand->config |= CONFIG_PS_256;
>> +            break;
>> +    case 512:
>> +            nand->config |= CONFIG_PS_512;
>> +            break;
>> +    case 1024:
>> +            nand->config |= CONFIG_PS_1024;
>> +            break;
>> +    case 2048:
>> +            nand->config |= CONFIG_PS_2048;
>> +            break;
>> +    case 4096:
>> +            nand->config |= CONFIG_PS_4096;
>> +            break;
>> +    default:
>> +            dev_err(dev, "Unsupported writesize %d\n", mtd->writesize);
>> +            return -ENODEV;
>> +    }
>> +
>> +    /* Store complete configuration in config_ecc */
>> +    nand->config_ecc |= nand->config;
>> +
>> +    /* Non-HW ECC read/writes complete OOB */
>> +    nand->config |= CONFIG_TAG_BYTE_SIZE(mtd->oobsize - 1);
>> +    writel_relaxed(nand->config, ctrl->regs + CONFIG);
>> +
>> +    ret = nand_scan_tail(mtd);
>> +    if (ret)
>> +            return ret;
>> +
>> +    /* Store tag layout when using HW ECC */
>> +    mtd_ooblayout_free(mtd, 0, &nand->tag);
>> +    nand->config_ecc |= CONFIG_TAG_BYTE_SIZE(nand->tag.length - 1);
>> +
>> +    ret = mtd_device_register(mtd, NULL, 0);
>> +    if (ret) {
>> +            dev_err(dev, "Failed to register mtd device: %d\n", ret);
>> +            nand_cleanup(chip);
>> +            return ret;
>> +    }
>> +
>> +    ctrl->chip = chip;
>> +
>> +    return 0;
>> +}
>> +
>> +static int tegra_nand_probe(struct platform_device *pdev)
>> +{
>> +    struct reset_control *rst;
>> +    struct tegra_nand_controller *ctrl;
>> +    struct resource *res;
>> +    int err = 0;
>> +
>> +    ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
>> +    if (!ctrl)
>> +            return -ENOMEM;
>> +
>> +    ctrl->dev = &pdev->dev;
>> +    nand_hw_control_init(&ctrl->controller);
>> +
>> +    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +    ctrl->regs = devm_ioremap_resource(&pdev->dev, res);
>> +    if (IS_ERR(ctrl->regs))
>> +            return PTR_ERR(ctrl->regs);
>> +
>> +    rst = devm_reset_control_get(&pdev->dev, "nand");
>> +    if (IS_ERR(rst))
>> +            return PTR_ERR(rst);
>> +
>> +    ctrl->clk = devm_clk_get(&pdev->dev, "nand");
>> +    if (IS_ERR(ctrl->clk))
>> +            return PTR_ERR(ctrl->clk);
>> +
>> +    err = clk_prepare_enable(ctrl->clk);
>> +    if (err)
>> +            return err;
>> +
>> +    err = reset_control_reset(rst);
>> +    if (err) {
>> +            dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
>> +            goto err_disable_clk;
>> +    }
>> +
>> +    writel_relaxed(HWSTATUS_CMD_DEFAULT, ctrl->regs + HWSTATUS_CMD);
>> +    writel_relaxed(HWSTATUS_MASK_DEFAULT, ctrl->regs + HWSTATUS_MASK);
>> +    writel_relaxed(INT_MASK, ctrl->regs + IER);
>> +
>> +    init_completion(&ctrl->command_complete);
>> +    init_completion(&ctrl->dma_complete);
>> +
>> +    ctrl->irq = platform_get_irq(pdev, 0);
>> +    err = devm_request_irq(&pdev->dev, ctrl->irq, tegra_nand_irq, 0,
>> +                           dev_name(&pdev->dev), ctrl);
>> +    if (err) {
>> +            dev_err(ctrl->dev, "Failed to get IRQ: %d\n", err);
>> +            goto err_disable_clk;
>> +    }
>> +
>> +    writel_relaxed(DMA_MST_CTRL_IS_DONE, ctrl->regs + DMA_MST_CTRL);
>> +
>> +    err = tegra_nand_chips_init(ctrl->dev, ctrl);
>> +    if (err)
>> +            goto err_disable_clk;
>> +
>> +    platform_set_drvdata(pdev, ctrl);
>> +
>> +    return 0;
>> +
>> +err_disable_clk:
>> +    clk_disable_unprepare(ctrl->clk);
>> +    return err;
>> +}
>> +
>> +static int tegra_nand_remove(struct platform_device *pdev)
>> +{
>> +    struct tegra_nand_controller *ctrl = platform_get_drvdata(pdev);
>> +
>> +    nand_release(nand_to_mtd(ctrl->chip));
>> +
>> +    clk_disable_unprepare(ctrl->clk);
>> +
>> +    return 0;
>> +}
>> +
>> +static const struct of_device_id tegra_nand_of_match[] = {
>> +    { .compatible = "nvidia,tegra20-nand" },
>> +    { /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, tegra_nand_of_match);
>> +
>> +static struct platform_driver tegra_nand_driver = {
>> +    .driver = {
>> +            .name = "tegra-nand",
>> +            .of_match_table = tegra_nand_of_match,
>> +    },
>> +    .probe = tegra_nand_probe,
>> +    .remove = tegra_nand_remove,
>> +};
>> +module_platform_driver(tegra_nand_driver);
>> +
>> +MODULE_DESCRIPTION("NVIDIA Tegra NAND driver");
>> +MODULE_AUTHOR("Thierry Reding <thierry.red...@nvidia.com>");
>> +MODULE_AUTHOR("Lucas Stach <d...@lynxeye.de>");
>> +MODULE_AUTHOR("Stefan Agner <ste...@agner.ch>");
>> +MODULE_LICENSE("GPL v2");

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