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Date: Mon, 28 May 2018 18:41:26 +0200
From: Benjamin Lindqvist <benjamin.lindqvist@...ian.se>
To: Stefan Agner <stefan@...er.ch>
Cc: Dmitry Osipenko <digetx@...il.com>,
Boris Brezillon <boris.brezillon@...tlin.com>,
David Woodhouse <dwmw2@...radead.org>,
Brian Norris <computersforpeace@...il.com>,
Marek VaĊĦut <marek.vasut@...il.com>,
robh+dt@...nel.org, mark.rutland@....com,
Thierry Reding <thierry.reding@...il.com>,
Michael Turquette <mturquette@...libre.com>, sboyd@...nel.org,
Lucas Stach <dev@...xeye.de>,
Miquel Raynal <miquel.raynal@...tlin.com>, richard@....at,
Marcel Ziswiler <marcel@...wiler.com>, krzk@...nel.org,
jonathanh@...dia.com, pdeschrijver@...dia.com,
Prashant Gaikwad <pgaikwad@...dia.com>,
Mirza Krak <mirza.krak@...il.com>,
linux-mtd@...ts.infradead.org, linux-tegra@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-clk@...r.kernel.org
Subject: Re: [PATCH v2 3/6] mtd: rawnand: add NVIDIA Tegra NAND Flash
controller driver
Note that it's certainly possible to encode U-Boot and kernel with
RS[4] and still use RS[8] for the rootfs even if the boot rom doesn't
support it. This whole 'use-bootable-ecc-only' business seems a bit
overengineered.
2018-05-28 14:43 GMT+02:00 Stefan Agner <stefan@...er.ch>:
> On 28.05.2018 13:57, Dmitry Osipenko wrote:
>> On 28.05.2018 00:54, 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.
>>>
>>> Signed-off-by: Lucas Stach <dev@...xeye.de>
>>> Signed-off-by: Stefan Agner <stefan@...er.ch>
>>> ---
>>> MAINTAINERS | 7 +
>>> drivers/mtd/nand/raw/Kconfig | 6 +
>>> drivers/mtd/nand/raw/Makefile | 1 +
>>> drivers/mtd/nand/raw/tegra_nand.c | 999 ++++++++++++++++++++++++++++++
>>> 4 files changed, 1013 insertions(+)
>>> create mode 100644 drivers/mtd/nand/raw/tegra_nand.c
>>>
>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>> index 58b9861ccf99..8cbbb7111742 100644
>>> --- a/MAINTAINERS
>>> +++ b/MAINTAINERS
>>> @@ -13844,6 +13844,13 @@ M: Laxman Dewangan <ldewangan@...dia.com>
>>> S: Supported
>>> F: drivers/input/keyboard/tegra-kbc.c
>>>
>>> +TEGRA NAND DRIVER
>>> +M: Stefan Agner <stefan@...er.ch>
>>> +M: Lucas Stach <dev@...xeye.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.reding@...il.com>
>>> S: Supported
>>> diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
>>> index 19a2b283fbbe..012c63c6ab47 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 on NVIDIA Tegra"
>>> + depends on ARCH_TEGRA || COMPILE_TEST
>>> + help
>>> + Enables support for NAND flash on NVIDIA Tegra SoC based boards.
>>> +
>>> 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..1a0833d97472
>>> --- /dev/null
>>> +++ b/drivers/mtd/nand/raw/tegra_nand.c
>>> @@ -0,0 +1,999 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Copyright (C) 2018 Stefan Agner <stefan@...er.ch>
>>> + * Copyright (C) 2014-2015 Lucas Stach <dev@...xeye.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 CMD 0x00
>>> +#define CMD_GO (1 << 31)
>>> +#define CMD_CLE (1 << 30)
>>> +#define CMD_ALE (1 << 29)
>>> +#define CMD_PIO (1 << 28)
>>> +#define CMD_TX (1 << 27)
>>> +#define CMD_RX (1 << 26)
>>> +#define CMD_SEC_CMD (1 << 25)
>>> +#define CMD_AFT_DAT (1 << 24)
>>> +#define CMD_TRANS_SIZE(x) (((x - 1) & 0xf) << 20)
>>> +#define CMD_A_VALID (1 << 19)
>>> +#define CMD_B_VALID (1 << 18)
>>> +#define CMD_RD_STATUS_CHK (1 << 17)
>>> +#define CMD_RBSY_CHK (1 << 16)
>>> +#define CMD_CE(x) (1 << (8 + ((x) & 0x7)))
>>> +#define CMD_CLE_SIZE(x) (((x - 1) & 0x3) << 4)
>>> +#define CMD_ALE_SIZE(x) (((x - 1) & 0xf) << 0)
>>> +
>>> +#define STATUS 0x04
>>> +
>>> +#define ISR 0x08
>>> +#define ISR_CORRFAIL_ERR (1 << 24)
>>> +#define ISR_UND (1 << 7)
>>> +#define ISR_OVR (1 << 6)
>>> +#define ISR_CMD_DONE (1 << 5)
>>> +#define ISR_ECC_ERR (1 << 4)
>>> +
>>> +#define IER 0x0c
>>> +#define IER_ERR_TRIG_VAL(x) (((x) & 0xf) << 16)
>>> +#define IER_UND (1 << 7)
>>> +#define IER_OVR (1 << 6)
>>> +#define IER_CMD_DONE (1 << 5)
>>> +#define IER_ECC_ERR (1 << 4)
>>> +#define IER_GIE (1 << 0)
>>> +
>>> +#define CFG 0x10
>>> +#define CFG_HW_ECC (1 << 31)
>>> +#define CFG_ECC_SEL (1 << 30)
>>> +#define CFG_ERR_COR (1 << 29)
>>> +#define CFG_PIPE_EN (1 << 28)
>>> +#define CFG_TVAL_4 (0 << 24)
>>> +#define CFG_TVAL_6 (1 << 24)
>>> +#define CFG_TVAL_8 (2 << 24)
>>> +#define CFG_SKIP_SPARE (1 << 23)
>>> +#define CFG_BUS_WIDTH_8 (0 << 21)
>>> +#define CFG_BUS_WIDTH_16 (1 << 21)
>>> +#define CFG_COM_BSY (1 << 20)
>>> +#define CFG_PS_256 (0 << 16)
>>> +#define CFG_PS_512 (1 << 16)
>>> +#define CFG_PS_1024 (2 << 16)
>>> +#define CFG_PS_2048 (3 << 16)
>>> +#define CFG_PS_4096 (4 << 16)
>>> +#define CFG_SKIP_SPARE_SIZE_4 (0 << 14)
>>> +#define CFG_SKIP_SPARE_SIZE_8 (1 << 14)
>>> +#define CFG_SKIP_SPARE_SIZE_12 (2 << 14)
>>> +#define CFG_SKIP_SPARE_SIZE_16 (3 << 14)
>>> +#define CFG_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) & 0xf) << 4)
>>> +#define TIMING_TRP(x) (((x) & 0xf) << 0)
>>> +
>>> +#define RESP 0x18
>>> +
>>> +#define TIMING_2 0x1c
>>> +#define TIMING_TADL(x) ((x) & 0xf)
>>> +
>>> +#define CMD_1 0x20
>>> +#define CMD_2 0x24
>>> +#define ADDR_1 0x28
>>> +#define ADDR_2 0x2c
>>> +
>>> +#define DMA_CTRL 0x30
>>> +#define DMA_CTRL_GO (1 << 31)
>>> +#define DMA_CTRL_IN (0 << 30)
>>> +#define DMA_CTRL_OUT (1 << 30)
>>> +#define DMA_CTRL_PERF_EN (1 << 29)
>>> +#define DMA_CTRL_IE_DONE (1 << 28)
>>> +#define DMA_CTRL_REUSE (1 << 27)
>>> +#define DMA_CTRL_BURST_1 (2 << 24)
>>> +#define DMA_CTRL_BURST_4 (3 << 24)
>>> +#define DMA_CTRL_BURST_8 (4 << 24)
>>> +#define DMA_CTRL_BURST_16 (5 << 24)
>>> +#define DMA_CTRL_IS_DONE (1 << 20)
>>> +#define DMA_CTRL_EN_A (1 << 2)
>>> +#define DMA_CTRL_EN_B (1 << 1)
>>> +
>>> +#define DMA_CFG_A 0x34
>>> +#define DMA_CFG_B 0x38
>>> +
>>> +#define FIFO_CTRL 0x3c
>>> +#define FIFO_CTRL_CLR_ALL (1 << 3)
>>> +
>>> +#define DATA_PTR 0x40
>>> +#define TAG_PTR 0x44
>>> +#define ECC_PTR 0x48
>>> +
>>> +#define DEC_STATUS 0x4c
>>> +#define DEC_STATUS_A_ECC_FAIL (1 << 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 (1 << 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 SKIP_SPARE_BYTES 4
>>> +#define BITS_PER_STEP_RS 18
>>> +#define BITS_PER_STEP_BCH 13
>>> +
>>> +struct tegra_nand_controller {
>>> + struct nand_hw_control controller;
>>> + void __iomem *regs;
>>> + struct clk *clk;
>>> + struct device *dev;
>>> + struct completion command_complete;
>>> + struct completion dma_complete;
>>> + bool last_read_error;
>>> + int cur_chip;
>>> + struct nand_chip *chip;
>>> +};
>>> +
>>> +struct tegra_nand_chip {
>>> + struct nand_chip chip;
>>> + struct gpio_desc *wp_gpio;
>>> +};
>>> +
>>> +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 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 = (BITS_PER_STEP_RS * chip->ecc.strength) / 8;
>>> +
>>> + 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, 8);
>>> +
>>> + 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, 8);
>>> +
>>> + 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 = (BITS_PER_STEP_BCH * chip->ecc.strength) / 8;
>>> +
>>> + 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_CTRL);
>>> + dev_dbg(ctrl->dev, "isr %08x\n", isr);
>>> +
>>> + if (!isr && !(dma & DMA_CTRL_IS_DONE))
>>> + return IRQ_NONE;
>>> +
>>> + if (isr & ISR_CORRFAIL_ERR)
>>> + ctrl->last_read_error = true;
>>> +
>>> + if (isr & ISR_CMD_DONE)
>>> + complete(&ctrl->command_complete);
>>> +
>>> + if (isr & ISR_UND)
>>> + dev_dbg(ctrl->dev, "FIFO underrun\n");
>>> +
>>> + if (isr & ISR_OVR)
>>> + dev_dbg(ctrl->dev, "FIFO overrun\n");
>>> +
>>> + /* handle DMA interrupts */
>>> + if (dma & DMA_CTRL_IS_DONE) {
>>> + writel(dma, ctrl->regs + DMA_CTRL);
>>> + complete(&ctrl->dma_complete);
>>> + }
>>> +
>>> + /* clear interrupts */
>>> + writel(isr, ctrl->regs + ISR);
>>> +
>>> + return IRQ_HANDLED;
>>> +}
>>> +
>>> +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 = -1, trfr_in_sz = 0, trfr_out_sz = 0, offset = 0;
>>> + bool first_cmd = true;
>>> + u32 cmd = 0;
>>> + u32 value;
>>> +
>>> + 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 |= CMD_CLE;
>>> + writel(instr->ctx.cmd.opcode, ctrl->regs + CMD_1);
>>> + } else {
>>> + cmd |= CMD_SEC_CMD;
>>> + writel(instr->ctx.cmd.opcode, ctrl->regs + CMD_2);
>>> + }
>>> + first_cmd = false;
>>> + break;
>>> + 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 |= CMD_ALE | CMD_ALE_SIZE(naddrs);
>>> + for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
>>> + addr1 |= *addrs++ << (8 * i);
>>> + naddrs -= i;
>>> + for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
>>> + addr2 |= *addrs++ << (8 * i);
>>> + writel(addr1, ctrl->regs + ADDR_1);
>>> + writel(addr2, ctrl->regs + ADDR_2);
>>> + break;
>>> +
>>> + case NAND_OP_DATA_IN_INSTR:
>>> + trfr_in_sz = nand_subop_get_data_len(subop, op_id);
>>> + offset = nand_subop_get_data_start_off(subop, op_id);
>>> +
>>> + cmd |= CMD_TRANS_SIZE(trfr_in_sz) | CMD_PIO | CMD_RX | CMD_A_VALID;
>>> +
>>> + instr_data_in = instr;
>>> + break;
>>> +
>>> + case NAND_OP_DATA_OUT_INSTR:
>>> + trfr_out_sz = nand_subop_get_data_len(subop, op_id);
>>> + offset = nand_subop_get_data_start_off(subop, op_id);
>>> + trfr_out_sz = min_t(size_t, trfr_out_sz, 4);
>>> +
>>> + cmd |= CMD_TRANS_SIZE(trfr_out_sz) | CMD_PIO | CMD_TX | CMD_A_VALID;
>>> +
>>> + memcpy(&value, instr->ctx.data.buf.out + offset, trfr_out_sz);
>>> + writel(value, ctrl->regs + RESP);
>>> +
>>> + break;
>>> + case NAND_OP_WAITRDY_INSTR:
>>> + cmd |= CMD_RBSY_CHK;
>>> + break;
>>> +
>>> + }
>>> + }
>>> +
>>> +
>>> + cmd |= CMD_GO | CMD_CE(ctrl->cur_chip);
>>> + writel(cmd, ctrl->regs + CMD);
>>> + wait_for_completion(&ctrl->command_complete);
>>
>> Could this and other completions stuck forever? What about
>> wait_for_completion_timeout() + HW reset / re-init on timeout?
>>
>
> They actually get stuck forever when I try to use DMA without HW ECC...
> I haven't seen it with HW ECC.
>
> But yes, _timeout variant makes sense here. Not sure if re-init is
> necessary since we rewrite all the relevant settings.
>
>
>>> +
>>> + if (instr_data_in) {
>>> + u32 value;
>>> + size_t n = min_t(size_t, trfr_in_sz, 4);
>>> +
>>> + value = readl(ctrl->regs + RESP);
>>> + memcpy(instr_data_in->ctx.data.buf.in + offset, &value, n);
>>> + }
>>> +
>>> + 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);
>>> +}
>>> +static void tegra_nand_select_chip(struct mtd_info *mtd, int chip_nr)
>>> +{
>>> + struct nand_chip *chip = mtd_to_nand(mtd);
>>> + struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>>> +
>>> + ctrl->cur_chip = chip_nr;
>>> +}
>>> +
>>> +static u32 tegra_nand_fill_address(struct tegra_nand_controller *ctrl,
>>> + struct nand_chip *chip, int page)
>>> +{
>>> + /* Lower 16-bits are column, always 0 */
>>> + writel(page << 16, ctrl->regs + ADDR_1);
>>> +
>>> + if (chip->options & NAND_ROW_ADDR_3) {
>>> + writel(page >> 16, ctrl->regs + ADDR_2);
>>> + return 5;
>>> + }
>>> +
>>> + return 4;
>>> +}
>>> +
>>> +static void tegra_nand_hw_ecc(struct tegra_nand_controller *ctrl,
>>> + struct nand_chip *chip, bool enable)
>>> +{
>>> + u32 value;
>>> +
>>> + switch (chip->ecc.algo) {
>>> + case NAND_ECC_RS:
>>> + value = readl(ctrl->regs + CFG);
>>> + if (enable)
>>> + value |= CFG_HW_ECC | CFG_ERR_COR;
>>> + else
>>> + value &= ~(CFG_HW_ECC | CFG_ERR_COR);
>>> + writel(value, ctrl->regs + CFG);
>>> + break;
>>> + case NAND_ECC_BCH:
>>> + value = readl(ctrl->regs + BCH_CONFIG);
>>> + if (enable)
>>> + value |= BCH_ENABLE;
>>> + else
>>> + value &= ~BCH_ENABLE;
>>> + writel(value, ctrl->regs + BCH_CONFIG);
>>> + break;
>>> + default:
>>> + dev_err(ctrl->dev, "Unsupported hardware ECC algorithm\n");
>>> + break;
>>> + }
>>> +}
>>> +
>>> +static int tegra_nand_read_page(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);
>>> + dma_addr_t dma_addr;
>>> + u32 value, addrs;
>>> + int ret, dma_len;
>>> +
>>> + writel(NAND_CMD_READ0, ctrl->regs + CMD_1);
>>> + writel(NAND_CMD_READSTART, ctrl->regs + CMD_2);
>>> +
>>> + addrs = tegra_nand_fill_address(ctrl, chip, page);
>>> +
>>> + dma_len = mtd->writesize + (oob_required ? mtd->oobsize : 0);
>>> + dma_addr = dma_map_single(ctrl->dev, buf, dma_len, DMA_FROM_DEVICE);
>>> + ret = dma_mapping_error(ctrl->dev, dma_addr);
>>> + if (ret) {
>>> + dev_err(ctrl->dev, "dma mapping error\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> + writel(mtd->writesize - 1, ctrl->regs + DMA_CFG_A);
>>> + writel(dma_addr, ctrl->regs + DATA_PTR);
>>> +
>>> + if (oob_required) {
>>> + struct mtd_oob_region oobregion;
>>> + dma_addr_t dma_addr_oob = dma_addr + mtd->writesize;
>>> +
>>> + mtd_ooblayout_free(mtd, 0, &oobregion);
>>> +
>>> + writel(oobregion.length - 1, ctrl->regs + DMA_CFG_B);
>>> + writel(dma_addr_oob + oobregion.offset, ctrl->regs + TAG_PTR);
>>> + } else {
>>> + writel(0, ctrl->regs + DMA_CFG_B);
>>> + writel(0, ctrl->regs + TAG_PTR);
>>> + }
>>> +
>>> + value = DMA_CTRL_GO | DMA_CTRL_IN | DMA_CTRL_PERF_EN |
>>> + DMA_CTRL_REUSE | DMA_CTRL_IE_DONE | DMA_CTRL_IS_DONE |
>>> + DMA_CTRL_BURST_16 | DMA_CTRL_EN_A;
>>> + if (oob_required)
>>> + value |= DMA_CTRL_EN_B;
>>> + writel(value, ctrl->regs + DMA_CTRL);
>>> +
>>> + value = CMD_CLE | CMD_ALE | CMD_ALE_SIZE(addrs) | CMD_SEC_CMD |
>>> + CMD_RBSY_CHK | CMD_GO | CMD_RX | CMD_TRANS_SIZE(9) |
>>> + CMD_A_VALID | CMD_CE(ctrl->cur_chip);
>>> + if (oob_required)
>>> + value |= CMD_B_VALID;
>>> + writel(value, ctrl->regs + CMD);
>>> +
>>> + wait_for_completion(&ctrl->command_complete);
>>> + wait_for_completion(&ctrl->dma_complete);
>>> +
>>> + dma_unmap_single(ctrl->dev, dma_addr, dma_len, DMA_FROM_DEVICE);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +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);
>>> + u32 value;
>>> + int ret;
>>> +
>>> + tegra_nand_hw_ecc(ctrl, chip, true);
>>> + ret = tegra_nand_read_page(mtd, chip, buf, oob_required, page);
>>> + tegra_nand_hw_ecc(ctrl, chip, false);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + /* If no correctable or un-correctable errors occured we can return 0 */
>>> + if (!ctrl->last_read_error)
>>> + return 0;
>>> +
>>> + /*
>>> + * Correctable or un-correctable errors did occure. NAND dec status
>>> + * contains information for all ECC selections
>>> + */
>>> + ctrl->last_read_error = false;
>>> + value = readl(ctrl->regs + DEC_STAT_BUF);
>>> +
>>> + if (value & DEC_STAT_BUF_FAIL_SEC_FLAG_MASK) {
>>> + /*
>>> + * The ECC isn't smart enough to figure out if a page is
>>> + * completely erased and flags an error in this case. So we
>>> + * check the read data here to figure out if it's a legitimate
>>> + * error or a false positive.
>>> + */
>>> + int i, ret;
>>> + int flips_threshold = chip->ecc.strength / 2;
>>> + int max_bitflips = 0;
>>> +
>>> + for (i = 0; i < chip->ecc.steps; i++) {
>>> + u8 *data = buf + (chip->ecc.size * i);
>>> +
>>> + ret = nand_check_erased_ecc_chunk(data, chip->ecc.size,
>>> + NULL, 0,
>>> + NULL, 0,
>>> + flips_threshold);
>>> + if (ret < 0)
>>> + mtd->ecc_stats.failed++;
>>> + else
>>> + max_bitflips = max(ret, max_bitflips);
>>> + }
>>> +
>>> + return max_bitflips;
>>> + } else {
>>> + int max_corr_cnt, corr_sec_flag;
>>> +
>>> + corr_sec_flag = (value & DEC_STAT_BUF_CORR_SEC_FLAG_MASK) >>
>>> + DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT;
>>> + max_corr_cnt = (value & DEC_STAT_BUF_MAX_CORR_CNT_MASK) >>
>>> + DEC_STAT_BUF_MAX_CORR_CNT_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;
>>> + }
>>> +
>>> +}
>>> +
>>> +static int tegra_nand_write_page(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);
>>> + dma_addr_t dma_addr;
>>> + u32 value, addrs;
>>> + int ret, dma_len;
>>> +
>>> + writel(NAND_CMD_SEQIN, ctrl->regs + CMD_1);
>>> + writel(NAND_CMD_PAGEPROG, ctrl->regs + CMD_2);
>>> +
>>> + addrs = tegra_nand_fill_address(ctrl, chip, page);
>>> +
>>> + dma_len = mtd->writesize + (oob_required ? mtd->oobsize : 0);
>>> + dma_addr = dma_map_single(ctrl->dev, (void *)buf, dma_len, DMA_TO_DEVICE);
>>> + ret = dma_mapping_error(ctrl->dev, dma_addr);
>>> + if (ret) {
>>> + dev_err(ctrl->dev, "dma mapping error\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> + writel(mtd->writesize - 1, ctrl->regs + DMA_CFG_A);
>>> + writel(dma_addr, ctrl->regs + DATA_PTR);
>>> +
>>> + if (oob_required) {
>>> + struct mtd_oob_region oobregion;
>>> + dma_addr_t dma_addr_oob = dma_addr + mtd->writesize;
>>> +
>>> + mtd_ooblayout_free(mtd, 0, &oobregion);
>>> +
>>> + writel(oobregion.length - 1, ctrl->regs + DMA_CFG_B);
>>> + writel(dma_addr_oob + oobregion.offset, ctrl->regs + TAG_PTR);
>>> + } else {
>>> + writel(0, ctrl->regs + DMA_CFG_B);
>>> + writel(0, ctrl->regs + TAG_PTR);
>>> + }
>>> +
>>> + value = DMA_CTRL_GO | DMA_CTRL_OUT | DMA_CTRL_PERF_EN |
>>> + DMA_CTRL_IE_DONE | DMA_CTRL_IS_DONE |
>>> + DMA_CTRL_BURST_16 | DMA_CTRL_EN_A;
>>> + if (oob_required)
>>> + value |= DMA_CTRL_EN_B;
>>> + writel(value, ctrl->regs + DMA_CTRL);
>>> +
>>> + value = CMD_CLE | CMD_ALE | CMD_ALE_SIZE(addrs) | CMD_SEC_CMD |
>>> + CMD_AFT_DAT | CMD_RBSY_CHK | CMD_GO | CMD_TX | CMD_A_VALID |
>>> + CMD_TRANS_SIZE(9) | CMD_CE(ctrl->cur_chip);
>>> + if (oob_required)
>>> + value |= CMD_B_VALID;
>>> + writel(value, ctrl->regs + CMD);
>>> +
>>> + wait_for_completion(&ctrl->command_complete);
>>> + wait_for_completion(&ctrl->dma_complete);
>>> +
>>> +
>>> + dma_unmap_single(ctrl->dev, dma_addr, dma_len, DMA_TO_DEVICE);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +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);
>>> + int ret;
>>> +
>>> + tegra_nand_hw_ecc(ctrl, chip, true);
>>> + ret = tegra_nand_write_page(mtd, chip, buf, oob_required, page);
>>> + 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);
>>> + if (val > 2)
>>> + val -= 3;
>>> + reg |= TIMING_TCR_TAR_TRR(val);
>>> +
>>> + val = DIV_ROUND_UP(max(max(timings->tCS_min, timings->tCH_min),
>>> + max(timings->tALS_min, timings->tALH_min)),
>>> + period);
>>> + if (val > 1)
>>> + val -= 2;
>>> + reg |= TIMING_TCS(val);
>>> +
>>> + val = DIV_ROUND_UP(max(timings->tRP_min, timings->tREA_max) + 6000,
>>> + period);
>>> + reg |= TIMING_TRP(val) | TIMING_TRP_RESP(val);
>>> +
>>> + reg |= TIMING_TWB(DIV_ROUND_UP(timings->tWB_max, period));
>>> + reg |= TIMING_TWHR(DIV_ROUND_UP(timings->tWHR_min, period));
>>> + reg |= TIMING_TWH(DIV_ROUND_UP(timings->tWH_min, period));
>>> + reg |= TIMING_TWP(DIV_ROUND_UP(timings->tWP_min, period));
>>> + reg |= TIMING_TRH(DIV_ROUND_UP(timings->tRHW_min, period));
>>> +
>>> + writel(reg, ctrl->regs + TIMING_1);
>>> +
>>> + val = DIV_ROUND_UP(timings->tADL_min, period);
>>> + if (val > 2)
>>> + val -= 3;
>>> + reg = TIMING_TADL(val);
>>> +
>>> + writel(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 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 nchips = of_get_child_count(np);
>>> + struct tegra_nand_chip *nand;
>>> + struct mtd_info *mtd;
>>> + struct nand_chip *chip;
>>> + unsigned long config, bch_config = 0;
>>> + int bits_per_step;
>>> + int err;
>>> +
>>> + if (nchips != 1) {
>>> + dev_err(dev, "currently only one NAND chip supported\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> + np_nand = of_get_next_child(np, NULL);
>>> +
>>> + nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
>>> + if (!nand) {
>>> + dev_err(dev, "could not allocate chip structure\n");
>>> + return -ENOMEM;
>>> + }
>>> +
>>> + nand->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_LOW);
>>> +
>>> + if (IS_ERR(nand->wp_gpio)) {
>>> + err = PTR_ERR(nand->wp_gpio);
>>> + dev_err(dev, "failed to request WP GPIO: %d\n", err);
>>> + return err;
>>> + }
>>> +
>>> + chip = &nand->chip;
>>> + chip->controller = &ctrl->controller;
>>> + ctrl->chip = chip;
>>> +
>>> + mtd = nand_to_mtd(chip);
>>> +
>>> + mtd->dev.parent = dev;
>>> + mtd->name = "tegra_nand";
>>> + mtd->owner = THIS_MODULE;
>>> +
>>> + nand_set_flash_node(chip, np_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;
>>> +
>>> + err = nand_scan_ident(mtd, 1, NULL);
>>> + if (err)
>>> + return err;
>>> +
>>> + if (chip->bbt_options & NAND_BBT_USE_FLASH)
>>> + chip->bbt_options |= NAND_BBT_NO_OOB;
>>> +
>>> + chip->ecc.mode = NAND_ECC_HW;
>>> + if (!chip->ecc.size)
>>> + chip->ecc.size = 512;
>>> + if (chip->ecc.size != 512)
>>> + return -EINVAL;
>>> +
>>> + chip->ecc.read_page = tegra_nand_read_page_hwecc;
>>> + chip->ecc.write_page = tegra_nand_write_page_hwecc;
>>> + /* Not functional for unknown reason...
>>> + chip->ecc.read_page_raw = tegra_nand_read_page;
>>> + chip->ecc.write_page_raw = tegra_nand_write_page;
>>> + */
>>> + config = readl(ctrl->regs + CFG);
>>> + config |= CFG_PIPE_EN | CFG_SKIP_SPARE | CFG_SKIP_SPARE_SIZE_4;
>>> +
>>> + if (chip->options & NAND_BUSWIDTH_16)
>>> + config |= CFG_BUS_WIDTH_16;
>>> +
>>> + 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);
>>> + switch (chip->ecc.strength) {
>>> + case 4:
>>> + config |= CFG_ECC_SEL | CFG_TVAL_4;
>>> + break;
>>> + case 6:
>>> + config |= CFG_ECC_SEL | CFG_TVAL_6;
>>> + break;
>>> + case 8:
>>> + config |= CFG_ECC_SEL | CFG_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);
>>> + switch (chip->ecc.strength) {
>>> + case 4:
>>> + bch_config = BCH_TVAL_4;
>>> + break;
>>> + case 8:
>>> + bch_config = BCH_TVAL_8;
>>> + break;
>>> + case 14:
>>> + bch_config = BCH_TVAL_14;
>>> + break;
>>> + case 16:
>>> + 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;
>>> + }
>>> +
>>> + chip->ecc.bytes = DIV_ROUND_UP(bits_per_step, 8);
>>> +
>>> + switch (mtd->writesize) {
>>> + case 256:
>>> + config |= CFG_PS_256;
>>> + break;
>>> + case 512:
>>> + config |= CFG_PS_512;
>>> + break;
>>> + case 1024:
>>> + config |= CFG_PS_1024;
>>> + break;
>>> + case 2048:
>>> + config |= CFG_PS_2048;
>>> + break;
>>> + case 4096:
>>> + config |= CFG_PS_4096;
>>> + break;
>>> + default:
>>> + dev_err(dev, "unhandled writesize %d\n", mtd->writesize);
>>> + return -ENODEV;
>>> + }
>>> +
>>> + writel(config, ctrl->regs + CFG);
>>> + writel(bch_config, ctrl->regs + BCH_CONFIG);
>>> +
>>> + err = nand_scan_tail(mtd);
>>> + if (err)
>>> + return err;
>>> +
>>> + config |= CFG_TAG_BYTE_SIZE(mtd_ooblayout_count_freebytes(mtd) - 1);
>>> + writel(config, ctrl->regs + CFG);
>>> +
>>> + err = mtd_device_register(mtd, NULL, 0);
>>> + if (err)
>>> + return err;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int tegra_nand_probe(struct platform_device *pdev)
>>> +{
>>> + struct reset_control *rst;
>>> + struct tegra_nand_controller *ctrl;
>>> + struct resource *res;
>>> + unsigned long value;
>>> + int irq, 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;
>>> +
>>> + reset_control_reset(rst);
>>
>> Technically reset_control_reset() could fail, so this should be:
>>
>> err = reset_control_reset(rst);
>> if (err)
>> goto err_disable_clk;
>>
>
> Ok.
>
> --
> Stefan
>
>>> +
>>> + value = HWSTATUS_RDSTATUS_MASK(1) | HWSTATUS_RDSTATUS_VALUE(0) |
>>> + HWSTATUS_RBSY_MASK(NAND_STATUS_READY) |
>>> + HWSTATUS_RBSY_VALUE(NAND_STATUS_READY);
>>> + writel(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
>>> + writel(value, ctrl->regs + HWSTATUS_MASK);
>>> +
>>> + init_completion(&ctrl->command_complete);
>>> + init_completion(&ctrl->dma_complete);
>>> +
>>> + /* clear interrupts */
>>> + value = readl(ctrl->regs + ISR);
>>> + writel(value, ctrl->regs + ISR);
>>> +
>>> + irq = platform_get_irq(pdev, 0);
>>> + err = devm_request_irq(&pdev->dev, irq, tegra_nand_irq, 0,
>>> + dev_name(&pdev->dev), ctrl);
>>> + if (err)
>>> + goto err_disable_clk;
>>> +
>>> + writel(DMA_CTRL_IS_DONE, ctrl->regs + DMA_CTRL);
>>> +
>>> + /* enable interrupts */
>>> + value = IER_UND | IER_OVR | IER_CMD_DONE | IER_ECC_ERR | IER_GIE;
>>> + writel(value, ctrl->regs + IER);
>>> +
>>> + /* reset config */
>>> + writel(0, ctrl->regs + CFG);
>>> +
>>> + 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 */ }
>>> +};
>>> +
>>> +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.reding@...dia.com>");
>>> +MODULE_AUTHOR("Lucas Stach <dev@...xeye.de>");
>>> +MODULE_AUTHOR("Stefan Agner <stefan@...er.ch>");
>>> +MODULE_LICENSE("GPL v2");
>>> +MODULE_DEVICE_TABLE(of, tegra_nand_of_match);
>>>
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