Re: [PATCH V5 RESEND] mtd: rawnand: Add Loongson1 NAND driver

From: Kelvin Cheung
Date: Sun Oct 09 2022 - 06:27:09 EST

Hi Miquel,
Sorry for the slow response.

Miquel Raynal <miquel.raynal@xxxxxxxxxxx> 于2021年8月7日周六 02:09写道：
>
> Hi Keguang,
>
> Sorry again for the very late review, here are my comments.
>
> Keguang Zhang <keguang.zhang@xxxxxxxxx> wrote on Fri, 21 May 2021
> 06:42:13 +0800:
>
> > From: Kelvin Cheung <keguang.zhang@xxxxxxxxx>
> >
> > This patch adds NAND driver for Loongson1B.
> >
> > Signed-off-by: Kelvin Cheung <keguang.zhang@xxxxxxxxx>
> > ---
> > V4 -> V5:
> > Update the driver to fit the raw NAND framework.
> > Implement exec_op() instead of legacy cmdfunc().
> > Use dma_request_chan() instead of dma_request_channel().
> > Some minor fixes and cleanups.
> > V3 -> V4:
> > Retrieve the controller from nand_hw_control.
> > V2 -> V3:
> > Replace __raw_readl/__raw_writel with readl/writel.
> > Split ls1x_nand into two structures: ls1x_nand_chip and
> > ls1x_nand_controller.
> > V1 -> V2:
> > Modify the dependency in Kconfig due to the changes of DMA
> > module.
> > ---
> > drivers/mtd/nand/raw/Kconfig | 8 +
> > drivers/mtd/nand/raw/Makefile | 1 +
> > drivers/mtd/nand/raw/loongson1_nand.c | 770 ++++++++++++++++++++++++++
> > 3 files changed, 779 insertions(+)
> > create mode 100644 drivers/mtd/nand/raw/loongson1_nand.c
> >
> > diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
> > index 30f061939560..63402e335df4 100644
> > --- a/drivers/mtd/nand/raw/Kconfig
> > +++ b/drivers/mtd/nand/raw/Kconfig
> > @@ -453,6 +453,14 @@ config MTD_NAND_ROCKCHIP
> > NFC v800: RK3308, RV1108
> > NFC v900: PX30, RK3326
> >
> > +config MTD_NAND_LOONGSON1
> > + tristate "Support for Loongson1 SoC NAND controller"
>
> Can you please match the style for the titles?
>
> > + depends on MACH_LOONGSON32
>
> || CROSS_COMPILE
>
> > + select MTD_NAND_ECC_SW_HAMMING
> > + select LOONGSON1_DMA
>
> Maybe this should be a depends on?
>
will change to depends on.

> > + help
> > + Enables support for NAND controller on Loongson1 SoCs.
> > +
> > comment "Misc"
> >
> > config MTD_SM_COMMON
> > diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
> > index d011c6c53f8f..50a51ad6ec21 100644
> > --- a/drivers/mtd/nand/raw/Makefile
> > +++ b/drivers/mtd/nand/raw/Makefile
> > @@ -57,6 +57,7 @@ obj-$(CONFIG_MTD_NAND_CADENCE) += cadence-nand-controller.o
> > obj-$(CONFIG_MTD_NAND_ARASAN) += arasan-nand-controller.o
> > obj-$(CONFIG_MTD_NAND_INTEL_LGM) += intel-nand-controller.o
> > obj-$(CONFIG_MTD_NAND_ROCKCHIP) += rockchip-nand-controller.o
> > +obj-$(CONFIG_MTD_NAND_LOONGSON1) += loongson1_nand.o
> >
> > nand-objs := nand_base.o nand_legacy.o nand_bbt.o nand_timings.o nand_ids.o
> > nand-objs += nand_onfi.o
> > diff --git a/drivers/mtd/nand/raw/loongson1_nand.c b/drivers/mtd/nand/raw/loongson1_nand.c
> > new file mode 100644
> > index 000000000000..b06e36ec32da
> > --- /dev/null
> > +++ b/drivers/mtd/nand/raw/loongson1_nand.c
> > @@ -0,0 +1,770 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * NAND Flash Driver for Loongson 1 SoC
> > + *
> > + * Copyright (C) 2015-2021 Zhang, Keguang <keguang.zhang@xxxxxxxxx>
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/clk.h>
> > +#include <linux/dmaengine.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/mtd/mtd.h>
> > +#include <linux/mtd/rawnand.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/sizes.h>
> > +
> > +#include <nand.h>
> > +
> > +/* Loongson 1 NAND Register Definitions */
> > +#define NAND_CMD 0x0
> > +#define NAND_ADDR1 0x4
> > +#define NAND_ADDR2 0x8
> > +#define NAND_TIMING 0xc
> > +#define NAND_IDL 0x10
> > +#define NAND_IDH 0x14
> > +#define NAND_STATUS 0x15
> > +#define NAND_PARAM 0x18
> > +#define NAND_OP_NUM 0x1c
> > +#define NAND_CS_RDY 0x20
> > +
> > +#define NAND_DMA_ADDR 0x40
> > +
> > +/* NAND Command Register Bits */
> > +#define OP_DONE BIT(10)
> > +#define OP_SPARE BIT(9)
> > +#define OP_MAIN BIT(8)
> > +#define CMD_STATUS BIT(7)
> > +#define CMD_RESET BIT(6)
> > +#define CMD_READID BIT(5)
> > +#define BLOCKS_ERASE BIT(4)
> > +#define CMD_ERASE BIT(3)
> > +#define CMD_WRITE BIT(2)
> > +#define CMD_READ BIT(1)
> > +#define CMD_VALID BIT(0)
> > +
> > +#define MAX_ADDR_CYC 5U
> > +#define MAX_ID_SIZE (NAND_STATUS - NAND_IDL)
>
> Strange. I guess you can hardcode it.
>
will remove MAX_ID_SIZE.

> > +#define SIZE_MASK GENMASK(11, 8)
> > +
> > +#define BITS_PER_WORD 32
> > +
> > +/* macros for registers read/write */
> > +#define nand_readl(nc, off) \
> > + readl((nc)->reg_base + (off))
> > +
> > +#define nand_writel(nc, off, val) \
> > + writel((val), (nc)->reg_base + (off))
> > +
> > +struct ls1x_nand_controller {
> > + void __iomem *reg_base;
> > + __le32 addr1_reg;
> > + __le32 addr2_reg;
> > +
> > + char *buf;
> > + unsigned int len;
> > + unsigned int rdy_timeout;
> > +
> > + /* DMA Engine stuff */
> > + struct dma_chan *dma_chan;
> > + dma_cookie_t dma_cookie;
> > + struct completion dma_complete;
> > +};
> > +
> > +struct ls1x_nand {
> > + struct device *dev;
> > + struct clk *clk;
> > + struct nand_chip chip;
> > + struct nand_controller controller;
> > + struct ls1x_nand_controller nc;
> > + struct plat_ls1x_nand *pdata;
> > +};
> > +
> > +static void ls1x_nand_dump_regs(struct nand_chip *chip)
> > +{
> > + struct ls1x_nand *nand = nand_get_controller_data(chip);
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > +
> > + print_hex_dump(KERN_INFO, "REG: ", DUMP_PREFIX_OFFSET, 16, 4,
> > + nc->reg_base, 0x44, false);
> > +}
> > +
> > +static void ls1x_nand_dma_callback(void *data)
> > +{
> > + struct ls1x_nand *nand = (struct ls1x_nand *)data;
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + enum dma_status status;
> > +
> > + status = dmaengine_tx_status(nc->dma_chan, nc->dma_cookie, NULL);
> > + if (likely(status == DMA_COMPLETE))
> > + dev_dbg(nand->dev, "DMA complete with cookie=%d\n",
> > + nc->dma_cookie);
> > + else
> > + dev_err(nand->dev, "DMA error with cookie=%d\n",
> > + nc->dma_cookie);
> > +
> > + complete(&nc->dma_complete);
> > +}
> > +
> > +static int ls1x_nand_dma_transfer(struct ls1x_nand *nand, bool is_write)
> > +{
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + struct dma_chan *chan = nc->dma_chan;
> > + struct dma_async_tx_descriptor *desc;
> > + enum dma_data_direction data_dir =
> > + is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
> > + enum dma_transfer_direction xfer_dir =
> > + is_write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
> > + dma_addr_t dma_addr;
> > + int ret;
> > +
> > + dma_addr = dma_map_single(chan->device->dev, nc->buf, nc->len,
> > + data_dir);
> > + if (dma_mapping_error(chan->device->dev, dma_addr)) {
> > + dev_err(nand->dev, "failed to map DMA buffer!\n");
> > + return -ENXIO;
> > + }
> > +
> > + desc = dmaengine_prep_slave_single(chan, dma_addr, nc->len, xfer_dir,
> > + DMA_PREP_INTERRUPT);
> > + if (!desc) {
> > + dev_err(nand->dev, "failed to prepare DMA descriptor!\n");
> > + ret = PTR_ERR(desc);
> > + goto err;
> > + }
> > + desc->callback = ls1x_nand_dma_callback;
> > + desc->callback_param = nand;
> > +
> > + nc->dma_cookie = dmaengine_submit(desc);
> > + ret = dma_submit_error(nc->dma_cookie);
> > + if (ret) {
> > + dev_err(nand->dev, "failed to submit DMA descriptor!\n");
> > + goto err;
> > + }
> > +
> > + dev_dbg(nand->dev, "issue DMA with cookie=%d\n", nc->dma_cookie);
> > + dma_async_issue_pending(chan);
> > +
> > + ret = wait_for_completion_timeout(&nc->dma_complete,
> > + msecs_to_jiffies(nc->rdy_timeout));
> > + if (ret <= 0) {
> > + dev_err(nand->dev, "DMA timeout!\n");
> > + dmaengine_terminate_all(chan);
> > + ret = -EIO;
> > + }
> > + ret = 0;
> > +err:
> > + dma_unmap_single(chan->device->dev, dma_addr, nc->len, data_dir);
> > +
> > + return ret;
> > +}
> > +
> > +static inline void ls1x_nand_parse_address(struct nand_chip *chip,
> > + const u8 *addrs,
> > + unsigned int naddrs, int cmd)
> > +{
> > + struct ls1x_nand *nand = nand_get_controller_data(chip);
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > +#if defined(CONFIG_LOONGSON1_LS1B)
>
> Please use a regular if (IS_DEFINED())
>
> I don't like this symbol anyway, you should get this information from a
> compatible (like the machine compatible) not from a Kconfig symbol.
>
will add DT support in the next version.

> > + unsigned int page_shift = chip->page_shift + 1;
> > +#endif
> > + int i;
> > +
> > + nc->addr1_reg = 0;
> > + nc->addr2_reg = 0;
> > +#if defined(CONFIG_LOONGSON1_LS1B)
> > + if (cmd == CMD_ERASE) {
> > + page_shift = chip->page_shift;
> > +
> > + for (i = 0; i < min(MAX_ADDR_CYC - 2, naddrs); i++)
> > + nc->addr1_reg |=
> > + (u32)addrs[i] << (page_shift + BITS_PER_BYTE * i);
> > + if (i == MAX_ADDR_CYC - 2)
> > + nc->addr2_reg |=
> > + (u32)addrs[i] >> (BITS_PER_WORD - page_shift -
> > + BITS_PER_BYTE * (i - 1));
> > +
> > + return;
> > + }
> > +
> > + for (i = 0; i < min(2U, naddrs); i++)
> > + nc->addr1_reg |= (u32)addrs[i] << BITS_PER_BYTE * i;
> > + for (i = 2; i < min(MAX_ADDR_CYC, naddrs); i++)
> > + nc->addr1_reg |=
> > + (u32)addrs[i] << (page_shift + BITS_PER_BYTE * (i - 2));
> > + if (i == MAX_ADDR_CYC)
> > + nc->addr2_reg |=
> > + (u32)addrs[i] >> (BITS_PER_WORD - page_shift -
> > + BITS_PER_BYTE * (i - 1));
> > +#elif defined(CONFIG_LOONGSON1_LS1C)
> > + if (cmd == CMD_ERASE) {
> > + for (i = 0; i < min(MAX_ADDR_CYC, naddrs); i++)
> > + nc->addr2_reg |= (u32)addrs[i] << BITS_PER_BYTE * i;
> > +
> > + return;
> > + }
> > +
> > + for (i = 0; i < min(MAX_ADDR_CYC, naddrs); i++) {
> > + if (i < 2)
> > + nc->addr1_reg |= (u32)addrs[i] << BITS_PER_BYTE * i;
> > + else
> > + nc->addr2_reg |=
> > + (u32)addrs[i] << BITS_PER_BYTE * (i - 2);
> > + }
> > +#endif
> > +}
> > +
> > +static int ls1x_nand_set_controller(struct nand_chip *chip,
> > + const struct nand_subop *subop, int cmd)
> > +{
> > + struct ls1x_nand *nand = nand_get_controller_data(chip);
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + unsigned int op_id;
> > +
> > + nc->buf = NULL;
> > + nc->len = 0;
> > + nc->rdy_timeout = 0;
> > +
> > + for (op_id = 0; op_id < subop->ninstrs; op_id++) {
> > + const struct nand_op_instr *instr = &subop->instrs[op_id];
> > + unsigned int offset, naddrs;
> > + const u8 *addrs;
> > +
> > + switch (instr->type) {
> > + case NAND_OP_CMD_INSTR:
> > + break;
>
> This is very suspicious. You should definitely do something with the
> command bytes, you should not guess the commands based on the format of
> the operation.
>
will remove this case.

> > + 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];
> > +
> > + ls1x_nand_parse_address(chip, addrs, naddrs, cmd);
> > + /* set NAND address */
> > + nand_writel(nc, NAND_ADDR1, nc->addr1_reg);
> > + nand_writel(nc, NAND_ADDR2, nc->addr2_reg);
> > + break;
> > + case NAND_OP_DATA_IN_INSTR:
> > + offset = nand_subop_get_data_start_off(subop, op_id);
> > + nc->len = nand_subop_get_data_len(subop, op_id);
> > + nc->buf = instr->ctx.data.buf.in + offset;
> > +
> > + if (!IS_ALIGNED(nc->len, chip->buf_align) ||
> > + !IS_ALIGNED((unsigned int)nc->buf, chip->buf_align))
> > + return -ENOTSUPP;
> > + /* set NAND data length */
> > + nand_writel(nc, NAND_OP_NUM, nc->len);
> > + break;
> > + case NAND_OP_DATA_OUT_INSTR:
> > + offset = nand_subop_get_data_start_off(subop, op_id);
> > + nc->len = nand_subop_get_data_len(subop, op_id);
> > + nc->buf = (void *)instr->ctx.data.buf.out + offset;
> > +
> > + if (!IS_ALIGNED(nc->len, chip->buf_align) ||
> > + !IS_ALIGNED((unsigned int)nc->buf, chip->buf_align))
> > + return -ENOTSUPP;
> > + /* set NAND data length */
> > + nand_writel(nc, NAND_OP_NUM, nc->len);
> > + break;
> > + case NAND_OP_WAITRDY_INSTR:
> > + nc->rdy_timeout = instr->ctx.waitrdy.timeout_ms;
> > + break;
> > + }
> > + }
> > +
> > + /*set NAND erase block count */
> > + if (cmd & CMD_ERASE)
> > + nand_writel(nc, NAND_OP_NUM, 1);
> > + /*set NAND operation region */
>
> Please fix all your comments in the driver, eg:

will do.
>
> /* Set NAND operation region */
>
> > + if (nc->buf && nc->len) {
> > + if (nc->addr1_reg & BIT(chip->page_shift))
> > + cmd |= OP_SPARE;
> > + else
> > + cmd |= OP_SPARE | OP_MAIN;
>
> Is this really needed? Can't you always stick to OP_SPARE | OP_MAIN?
>
will do.

> > + }
> > +
> > + /*set NAND command */
> > + nand_writel(nc, NAND_CMD, cmd);
> > + /* Trigger operation */
> > + nand_writel(nc, NAND_CMD, nand_readl(nc, NAND_CMD) | CMD_VALID);
> > +
> > + return 0;
> > +}
> > +
> > +static inline int ls1x_nand_wait_for_op_done(struct ls1x_nand_controller *nc)
> > +{
> > + unsigned int val;
> > + int ret = 0;
> > +
> > + /* Wait for operation done */
> > + if (nc->rdy_timeout)
> > + ret = readl_relaxed_poll_timeout(nc->reg_base + NAND_CMD, val,
> > + val & OP_DONE, 0,
> > + nc->rdy_timeout * 1000);
> > +
> > + return ret;
> > +}
> > +
> > +static int ls1x_nand_reset_exec(struct nand_chip *chip,
> > + const struct nand_subop *subop)
> > +{
> > + struct ls1x_nand *nand = nand_get_controller_data(chip);
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + int ret;
> > +
> > + ls1x_nand_set_controller(chip, subop, CMD_RESET);
> > +
> > + ret = ls1x_nand_wait_for_op_done(nc);
> > + if (ret)
> > + dev_err(nand->dev, "CMD_RESET failed! %d\n", ret);
> > +
> > + return ret;
> > +}
> > +
> > +static int ls1x_nand_read_id_exec(struct nand_chip *chip,
> > + const struct nand_subop *subop)
> > +{
> > + struct ls1x_nand *nand = nand_get_controller_data(chip);
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + int idl, i;
> > + int ret;
> > +
> > + ls1x_nand_set_controller(chip, subop, CMD_READID);
> > +
> > + ret = ls1x_nand_wait_for_op_done(nc);
> > + if (ret) {
> > + dev_err(nand->dev, "CMD_READID failed! %d\n", ret);
> > + return ret;
> > + }
> > +
> > + idl = (nand_readl(nc, NAND_IDL));
>
> Unneeded outer ( ).
>
will do.

> > + for (i = 0; i < min_t(unsigned int, nc->len, MAX_ID_SIZE); i++)
>
> The core enforces the number of data cycles to be less or
> equal than MAX_ID_SIZE if correctly described below (see the comment in
> the exec_op array) so you don't need this min_t() here.
>
will remove min_t().

> Please use { } to enclose the if/else block.
>
> > + if (i > 0)
>
will do.
> This looks very suspicious, I would expect the condition to be i < 4
>
> > + nc->buf[i] = *((char *)&idl + 4 - i);
>
> Please rewrite this, it is hard to follow.
>
will do.
> > + else
> > + nc->buf[i] = (char)(nand_readl(nc, NAND_IDH));
> > +
> > + return ret;
> > +}
> > +
> > +static int ls1x_nand_erase_exec(struct nand_chip *chip,
> > + const struct nand_subop *subop)
> > +{
> > + struct ls1x_nand *nand = nand_get_controller_data(chip);
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + int ret;
> > +
> > + ls1x_nand_set_controller(chip, subop, CMD_ERASE);
> > +
> > + ret = ls1x_nand_wait_for_op_done(nc);
> > + if (ret)
> > + dev_err(nand->dev, "CMD_ERASE failed! %d\n", ret);
> > +
> > + return ret;
> > +}
> > +
> > +static int ls1x_nand_read_exec(struct nand_chip *chip,
> > + const struct nand_subop *subop)
> > +{
> > + struct ls1x_nand *nand = nand_get_controller_data(chip);
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + int ret;
> > +
> > + ls1x_nand_set_controller(chip, subop, CMD_READ);
> > +
> > + ret = ls1x_nand_dma_transfer(nand, false);
>
> Please use an intermediate variable such as bool write = false; (same
> below)
>
will do.
> > + if (ret)
> > + return ret;
> > +
> > + ret = ls1x_nand_wait_for_op_done(nc);
> > + if (ret)
> > + dev_err(nand->dev, "CMD_READ failed! %d\n", ret);
> > +
> > + return ret;
> > +}
> > +
> > +static int ls1x_nand_write_exec(struct nand_chip *chip,
> > + const struct nand_subop *subop)
> > +{
> > + struct ls1x_nand *nand = nand_get_controller_data(chip);
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + int ret;
> > +
> > + ls1x_nand_set_controller(chip, subop, CMD_WRITE);
> > +
> > + ret = ls1x_nand_dma_transfer(nand, true);
> > + if (ret)
> > + return ret;
> > +
> > + ret = ls1x_nand_wait_for_op_done(nc);
> > + if (ret)
> > + dev_err(nand->dev, "CMD_WRITE failed! %d\n", ret);
> > +
> > + return ret;
> > +}
> > +
> > +static int ls1x_nand_read_status_exec(struct nand_chip *chip,
> > + const struct nand_subop *subop)
> > +{
> > + struct ls1x_nand *nand = nand_get_controller_data(chip);
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + int ret;
> > +
> > + ls1x_nand_set_controller(chip, subop, CMD_STATUS);
> > +
> > + ret = ls1x_nand_wait_for_op_done(nc);
> > + if (ret) {
> > + dev_err(nand->dev, "CMD_STATUS failed! %d\n", ret);
> > + return ret;
> > + }
> > +
> > + nc->buf[0] = nand_readl(nc, NAND_IDH) >> BITS_PER_BYTE;
>
> This looks very specific to the status cmd, which is not a valid
> implementation. Can you turn this function generic to any cmd+data
> bytes? (the number of data bytes could be different than 1).
>
will read NAND_STATUS directly.
> > +
> > + return ret;
> > +}
> > +
> > +static const struct nand_op_parser ls1x_nand_op_parser = NAND_OP_PARSER(
> > + NAND_OP_PARSER_PATTERN(
> > + ls1x_nand_reset_exec,
> > + NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > + NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
> > + NAND_OP_PARSER_PATTERN(
> > + ls1x_nand_read_id_exec,
> > + NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > + NAND_OP_PARSER_PAT_ADDR_ELEM(false, MAX_ADDR_CYC),
> > + NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, 8)),
>
> Please use the definition used above ^
>
> > + NAND_OP_PARSER_PATTERN(
> > + ls1x_nand_erase_exec,
> > + NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > + NAND_OP_PARSER_PAT_ADDR_ELEM(false, MAX_ADDR_CYC),
> > + NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > + NAND_OP_PARSER_PAT_WAITRDY_ELEM(false)),
> > + NAND_OP_PARSER_PATTERN(
> > + ls1x_nand_read_exec,
> > + NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > + NAND_OP_PARSER_PAT_ADDR_ELEM(false, MAX_ADDR_CYC),
> > + NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > + NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
> > + NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, 0)),
> > + NAND_OP_PARSER_PATTERN(
> > + ls1x_nand_write_exec,
> > + NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > + NAND_OP_PARSER_PAT_ADDR_ELEM(false, MAX_ADDR_CYC),
> > + NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, 0),
> > + NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > + NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
> > + NAND_OP_PARSER_PATTERN(
> > + ls1x_nand_read_status_exec,
> > + NAND_OP_PARSER_PAT_CMD_ELEM(false),
> > + NAND_OP_PARSER_PAT_DATA_IN_ELEM(false, 1)),
> > + );
> > +
> > +static int ls1x_nand_exec_op(struct nand_chip *chip,
> > + const struct nand_operation *op, bool check_only)
> > +{
> > + return nand_op_parser_exec_op(chip, &ls1x_nand_op_parser, op,
> > + check_only);
> > +}
> > +
> > +static int ls1x_nand_read_subpage(struct nand_chip *chip,
> > + unsigned int data_offs, unsigned int readlen,
> > + unsigned char *bufpoi, int page)
> > +{
>
> There is nothing specific to your controller in that helper, why do you
> need it?
>
Just want to make the most of monolithic_read.
I should modify the nand subsystem instead of implementing own helper, right?
I will submit a separate patch for this.

> > + struct mtd_info *mtd = nand_to_mtd(chip);
> > + int start_step, end_step, num_steps, ret;
> > + char *p;
> > + int data_col_addr, i;
> > + int datafrag_len, eccfrag_len, aligned_len, aligned_pos;
> > + int busw = (chip->options & NAND_BUSWIDTH_16) ? 2 : 1;
> > + int index, section = 0;
> > + unsigned int max_bitflips = 0;
> > + struct mtd_oob_region oobregion = { };
> > +
> > + /* Read the whole page and OOB data */
> > + ret = chip->ecc.read_page_raw(chip, bufpoi, 1, page);
> > + if (ret)
> > + return ret;
> > +
> > + /* Column address within the page aligned to ECC size (256bytes) */
> > + start_step = data_offs / chip->ecc.size;
> > + end_step = (data_offs + readlen - 1) / chip->ecc.size;
> > + num_steps = end_step - start_step + 1;
> > + index = start_step * chip->ecc.bytes;
> > +
> > + /* Data size aligned to ECC ecc.size */
> > + datafrag_len = num_steps * chip->ecc.size;
> > + eccfrag_len = num_steps * chip->ecc.bytes;
> > +
> > + data_col_addr = start_step * chip->ecc.size;
> > + /* If we read not a page aligned data */
> > + p = bufpoi + data_col_addr;
> > +
> > + /* Calculate ECC */
> > + for (i = 0; i < eccfrag_len; i += chip->ecc.bytes, p += chip->ecc.size)
> > + chip->ecc.calculate(chip, p, &chip->ecc.calc_buf[i]);
> > +
> > + ret = mtd_ooblayout_find_eccregion(mtd, index, &section, &oobregion);
> > + if (ret)
> > + return ret;
> > +
> > + aligned_pos = oobregion.offset & ~(busw - 1);
> > + aligned_len = eccfrag_len;
> > + if (oobregion.offset & (busw - 1))
> > + aligned_len++;
> > + if ((oobregion.offset + (num_steps * chip->ecc.bytes)) & (busw - 1))
> > + aligned_len++;
> > +
> > + memcpy(&chip->oob_poi[aligned_pos],
> > + bufpoi + mtd->writesize + aligned_pos, aligned_len);
> > +
> > + ret = mtd_ooblayout_get_eccbytes(mtd, chip->ecc.code_buf,
> > + chip->oob_poi, index, eccfrag_len);
> > + if (ret)
> > + return ret;
> > +
> > + p = bufpoi + data_col_addr;
> > + for (i = 0; i < eccfrag_len; i += chip->ecc.bytes, p += chip->ecc.size) {
> > + int stat;
> > +
> > + stat = chip->ecc.correct(chip, p, &chip->ecc.code_buf[i],
> > + &chip->ecc.calc_buf[i]);
> > + if (stat)
> > + ls1x_nand_dump_regs(chip);
> > +
> > + if (stat == -EBADMSG &&
> > + (chip->ecc.options & NAND_ECC_GENERIC_ERASED_CHECK)) {
> > + /* check for empty pages with bitflips */
> > + stat = nand_check_erased_ecc_chunk(p, chip->ecc.size,
> > + &chip->ecc.code_buf[i],
> > + chip->ecc.bytes,
> > + NULL, 0,
> > + chip->ecc.strength);
> > + }
> > +
> > + if (stat < 0) {
> > + mtd->ecc_stats.failed++;
> > + } else {
> > + mtd->ecc_stats.corrected += stat;
> > + max_bitflips = max_t(unsigned int, max_bitflips, stat);
> > + }
> > + }
> > + return max_bitflips;
> > +}
> > +
> > +static int ls1x_nand_attach_chip(struct nand_chip *chip)
> > +{
> > + struct ls1x_nand *nand = nand_get_controller_data(chip);
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + struct plat_ls1x_nand *pdata = nand->pdata;
> > + int hold_cycle = pdata->hold_cycle;
> > + int wait_cycle = pdata->wait_cycle;
> > + u64 chipsize = nanddev_target_size(&chip->base);
> > + int cell_size = 0;
> > +
>
> You should somehow be able to configure the controller to work in
> software mode or without ECC for debug purposes. Please add and test
> those two features.
>
will do.

> > + switch (chipsize) {
> > + case SZ_128M:
> > + cell_size = 0x0;
> > + break;
> > + case SZ_256M:
> > + cell_size = 0x1;
> > + break;
> > + case SZ_512M:
> > + cell_size = 0x2;
> > + break;
> > + case SZ_1G:
> > + cell_size = 0x3;
> > + break;
> > + case SZ_2G:
> > + cell_size = 0x4;
> > + break;
> > + case SZ_4G:
> > + cell_size = 0x5;
> > + break;
> > + case (SZ_2G * SZ_4G): /*8G */
> > + cell_size = 0x6;
> > + break;
> > + case (SZ_4G * SZ_4G): /*16G */
> > + cell_size = 0x7;
> > + break;
> > + default:
> > + dev_err(nand->dev, "unsupported chip size: %llu MB\n",
> > + chipsize);
> > + break;
> > + }
> > +
> > + if (hold_cycle && wait_cycle)
> > + nand_writel(nc, NAND_TIMING,
> > + (hold_cycle << BITS_PER_BYTE) | wait_cycle);
> > + nand_writel(nc, NAND_PARAM,
> > + (nand_readl(nc, NAND_PARAM) & ~SIZE_MASK) | cell_size <<
> > + BITS_PER_BYTE);
>
> Please do this in three steps for readability:
>
> param = nand_readl()
> param |= cell_size...
> nand_writel()
>
will do.
> > +
> > + chip->ecc.read_page_raw = nand_monolithic_read_page_raw;
> > + chip->ecc.write_page_raw = nand_monolithic_write_page_raw;
>
> Nice :)
>
> > +
> > + return 0;
> > +}
> > +
> > +static const struct nand_controller_ops ls1x_nc_ops = {
> > + .exec_op = ls1x_nand_exec_op,
> > + .attach_chip = ls1x_nand_attach_chip,
> > +};
> > +
> > +static void ls1x_nand_controller_cleanup(struct ls1x_nand *nand)
> > +{
> > + if (nand->nc.dma_chan)
> > + dma_release_channel(nand->nc.dma_chan);
> > +}
> > +
> > +static int ls1x_nand_controller_init(struct ls1x_nand *nand,
> > + struct platform_device *pdev)
> > +{
> > + struct ls1x_nand_controller *nc = &nand->nc;
> > + struct device *dev = &pdev->dev;
> > + struct dma_slave_config cfg;
> > + struct resource *res;
> > + int ret;
> > +
> > + nc->reg_base = devm_platform_ioremap_resource(pdev, 0);
> > + if (IS_ERR(nc->reg_base))
> > + return PTR_ERR(nc->reg_base);
> > +
> > + res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
> > + if (!res) {
> > + dev_err(dev, "failed to get DMA information!\n");
> > + return -ENXIO;
> > + }
> > +
> > + nc->dma_chan = dma_request_chan(dev, res->name);
> > + if (!nc->dma_chan) {
> > + dev_err(dev, "failed to request DMA channel!\n");
> > + return -EBUSY;
> > + }
> > + dev_info(dev, "got %s for %s access\n",
> > + dma_chan_name(nc->dma_chan), dev_name(dev));
> > +
> > + cfg.src_addr = CPHYSADDR(nc->reg_base + NAND_DMA_ADDR);
> > + cfg.dst_addr = CPHYSADDR(nc->reg_base + NAND_DMA_ADDR);
> > + cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> > + cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> > + ret = dmaengine_slave_config(nc->dma_chan, &cfg);
> > + if (ret) {
> > + dev_err(dev, "failed to config DMA channel!\n");
> > + dma_release_channel(nc->dma_chan);
> > + return ret;
> > + }
> > +
> > + init_completion(&nc->dma_complete);
> > +
> > + return 0;
> > +}
> > +
> > +static int ls1x_nand_chip_init(struct ls1x_nand *nand)
> > +{
> > + struct nand_chip *chip = &nand->chip;
> > + struct mtd_info *mtd = nand_to_mtd(chip);
> > + struct plat_ls1x_nand *pdata = nand->pdata;
> > + int ret = 0;
> > +
> > + chip->controller = &nand->controller;
> > + chip->options = NAND_NO_SUBPAGE_WRITE | NAND_USES_DMA | NAND_BROKEN_XD;
> > + chip->buf_align = 16;
> > + chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
> > + chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
>
> ECC configuration should only be done in ->attach_chip().
>
will do.

> > + nand_set_controller_data(chip, nand);
> > +
> > + mtd->dev.parent = nand->dev;
> > + mtd->name = "ls1x-nand";
> > + mtd->owner = THIS_MODULE;
> > +
> > + ret = nand_scan(chip, 1);
> > + if (ret)
> > + return ret;
> > +
> > + chip->ecc.read_subpage = ls1x_nand_read_subpage;
>
> Do you really need this? It looks like your implementation of
> read_subpage is very similar to the one from the core.
>
will remove this line.
> > +
> > + ret = mtd_device_register(mtd, pdata->parts, pdata->nr_parts);
> > + if (ret) {
> > + dev_err(nand->dev, "failed to register MTD device! %d\n", ret);
> > + nand_cleanup(chip);
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +static int ls1x_nand_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct plat_ls1x_nand *pdata;
> > + struct ls1x_nand *nand;
>
> Please use another name for the variable, "nand"/"chip" is used by the
> core for the nand_chip structure, for yours you can name it eg ls1x or
> lsnand.
>
will do.

> > + int ret;
> > +
> > + pdata = dev_get_platdata(dev);
> > + if (!pdata) {
> > + dev_err(dev, "platform data missing!\n");
> > + return -EINVAL;
> > + }
> > +
> > + nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
> > + if (!nand)
> > + return -ENOMEM;
> > +
> > + nand->pdata = pdata;
> > + nand->dev = dev;
> > + nand->controller.ops = &ls1x_nc_ops;
> > + nand_controller_init(&nand->controller);
> > +
> > + ret = ls1x_nand_controller_init(nand, pdev);
>
> I'm not sure this deserves a helper (same for the chip init) but why
> not.
>
> > + if (ret)
> > + return ret;
> > +
> > + nand->clk = devm_clk_get(dev, pdev->name);
> > + if (IS_ERR(nand->clk)) {
> > + dev_err(dev, "failed to get %s clock!\n", pdev->name);
> > + return PTR_ERR(nand->clk);
> > + }
> > + clk_prepare_enable(nand->clk);
> > +
> > + ret = ls1x_nand_chip_init(nand);
> > + if (ret) {
> > + clk_disable_unprepare(nand->clk);
> > + goto err;
> > + }
> > +
> > + platform_set_drvdata(pdev, nand);
> > + dev_info(dev, "Loongson1 NAND driver registered\n");
>
> I don't think this is useful, you can drop that trace.
>
will do.

> > +
> > + return 0;
> > +err:
> > + ls1x_nand_controller_cleanup(nand);
> > + return ret;
> > +}
> > +
> > +static int ls1x_nand_remove(struct platform_device *pdev)
> > +{
> > + struct ls1x_nand *nand = platform_get_drvdata(pdev);
> > + struct nand_chip *chip = &nand->chip;
> > +
> > + mtd_device_unregister(nand_to_mtd(chip));
>
> ret = mtd_device_unregister()
> WARN_ON(ret);
>
will do.

> > + nand_cleanup(chip);
> > + clk_disable_unprepare(nand->clk);
> > + ls1x_nand_controller_cleanup(nand);
> > +
> > + return 0;
> > +}
> > +
> > +static struct platform_driver ls1x_nand_driver = {
> > + .probe = ls1x_nand_probe,
> > + .remove = ls1x_nand_remove,
> > + .driver = {
> > + .name = "ls1x-nand",
>
> ls1x-nand-controller
>
Can I keep the name "ls1x-nand"?
Thanks!

> > + .owner = THIS_MODULE,
> > + },
> > +};
> > +
> > +module_platform_driver(ls1x_nand_driver);
> > +
> > +MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@xxxxxxxxx>");
> > +MODULE_DESCRIPTION("Loongson1 NAND Flash driver");
> > +MODULE_LICENSE("GPL");
> >
> > base-commit: fd0d8d85f7230052e638a56d1bfea170c488e6bc
>
>
>
>
> Thanks,
> Miquèl
--
Best regards,

Kelvin Cheung