[PATCH V1 4/7] mtd: nand: add Loongson1 NAND driver
Boris Brezillon
boris.brezillon at free-electrons.com
Sun Apr 17 12:38:47 PDT 2016
Hi Keguang,
On Wed, 6 Apr 2016 20:34:52 +0800
Keguang Zhang <keguang.zhang at gmail.com> wrote:
> From: Kelvin Cheung <keguang.zhang at gmail.com>
>
> This patch adds NAND driver for Loongson1B.
>
> Signed-off-by: Kelvin Cheung <keguang.zhang at gmail.com>
> ---
> drivers/mtd/nand/Kconfig | 8 +
> drivers/mtd/nand/Makefile | 1 +
> drivers/mtd/nand/loongson1_nand.c | 519 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 528 insertions(+)
> create mode 100644 drivers/mtd/nand/loongson1_nand.c
>
> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
> index f05e0e9..d90f545 100644
> --- a/drivers/mtd/nand/Kconfig
> +++ b/drivers/mtd/nand/Kconfig
> @@ -563,4 +563,12 @@ config MTD_NAND_QCOM
> Enables support for NAND flash chips on SoCs containing the EBI2 NAND
> controller. This controller is found on IPQ806x SoC.
>
> +config MTD_NAND_LOONGSON1
> + tristate "Support for Loongson1 SoC NAND controller"
> + depends on MACH_LOONGSON32
> + select DMADEVICES
> + select DMA_LOONGSON1
> + help
> + Enables support for NAND Flash on Loongson1 SoC based boards.
> +
> endif # MTD_NAND
> diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
> index f553353..0310c0b 100644
> --- a/drivers/mtd/nand/Makefile
> +++ b/drivers/mtd/nand/Makefile
> @@ -57,5 +57,6 @@ obj-$(CONFIG_MTD_NAND_SUNXI) += sunxi_nand.o
> obj-$(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_LOONGSON1) += loongson1_nand.o
>
> nand-objs := nand_base.o nand_bbt.o nand_timings.o
> diff --git a/drivers/mtd/nand/loongson1_nand.c b/drivers/mtd/nand/loongson1_nand.c
> new file mode 100644
> index 0000000..28f7ca7
> --- /dev/null
> +++ b/drivers/mtd/nand/loongson1_nand.c
> @@ -0,0 +1,519 @@
> +/*
> + * NAND Flash Driver for Loongson 1 SoC
> + *
> + * Copyright (C) 2015-2016 Zhang, Keguang <keguang.zhang at gmail.com>
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/clk.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/nand.h>
> +#include <linux/sizes.h>
> +
> +#include <nand.h>
> +
> +/* Loongson 1 NAND Register Definitions */
> +#define NAND_CMD 0x0
> +#define NAND_ADDRL 0x4
> +#define NAND_ADDRH 0x8
> +#define NAND_TIMING 0xc
> +#define NAND_IDL 0x10
> +#define NAND_IDH 0x14
> +#define NAND_STATUS 0x14
> +#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 LS1X_NAND_TIMEOUT 20
> +
> +/* macros for registers read/write */
> +#define nand_readl(nand, off) \
> + __raw_readl((nand)->reg_base + (off))
> +
> +#define nand_writel(nand, off, val) \
> + __raw_writel((val), (nand)->reg_base + (off))
Are you sure you want to use __raw primitives here? What about
endianness and memory barriers? Is it safe to skip them in your use
case?
> +
> +#define set_cmd(nand, ctrl) \
> + nand_writel(nand, NAND_CMD, ctrl)
> +
> +#define start_nand(nand) \
> + nand_writel(nand, NAND_CMD, nand_readl(nand, NAND_CMD) | CMD_VALID)
> +
> +struct ls1x_nand {
> + struct platform_device *pdev;
> + struct nand_chip chip;
> +
> + struct clk *clk;
> + void __iomem *reg_base;
> +
> + int cmd_val;
> +
> + char datareg[8];
> + char *data_ptr;
> +
> + /* DMA stuff */
> + unsigned char *dma_buf;
> + unsigned int buf_off;
> + unsigned int buf_len;
> +
> + /* DMA Engine stuff */
> + unsigned int dma_chan_id;
> + struct dma_chan *dma_chan;
> + dma_cookie_t dma_cookie;
> + struct completion dma_complete;
> + void __iomem *dma_desc;
> +};
Please separate the NAND controller and NAND chip information in 2
different structures. See the sunxi_nand driver if you need an example.
> +
> +static void dma_callback(void *data)
> +{
> + struct ls1x_nand *nand = (struct ls1x_nand *)data;
> + struct mtd_info *mtd = nand_to_mtd(&nand->chip);
> + struct dma_tx_state state;
> + enum dma_status status;
> +
> + status = dmaengine_tx_status(nand->dma_chan, nand->dma_cookie, &state);
> + if (likely(status == DMA_COMPLETE))
> + dev_dbg(mtd->dev.parent, "DMA complete with cookie=%d\n",
> + nand->dma_cookie);
> + else
> + dev_err(mtd->dev.parent, "DMA error with cookie=%d\n",
> + nand->dma_cookie);
> +
> + complete(&nand->dma_complete);
> +}
> +
> +static int setup_dma(struct ls1x_nand *nand)
> +{
> + struct mtd_info *mtd = nand_to_mtd(&nand->chip);
> + struct dma_slave_config cfg;
> + dma_cap_mask_t mask;
> + int ret;
> +
> + /* allocate DMA buffer */
> + nand->dma_buf = devm_kzalloc(mtd->dev.parent,
> + mtd->writesize + mtd->oobsize, GFP_KERNEL);
> + if (!nand->dma_buf)
> + return -ENOMEM;
> +
> + dma_cap_zero(mask);
> + dma_cap_set(DMA_SLAVE, mask);
> + nand->dma_chan = dma_request_channel(mask, ls1x_dma_filter_fn,
> + &nand->dma_chan_id);
> + if (!nand->dma_chan) {
> + dev_err(mtd->dev.parent, "failed to request DMA channel\n");
> + return -EBUSY;
> + }
> + dev_info(mtd->dev.parent, "got %s for %s access\n",
> + dma_chan_name(nand->dma_chan), dev_name(mtd->dev.parent));
> +
> + cfg.src_addr = CPHYSADDR(nand->reg_base + NAND_DMA_ADDR);
> + cfg.dst_addr = CPHYSADDR(nand->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(nand->dma_chan, &cfg);
> + if (ret) {
> + dev_err(mtd->dev.parent, "failed to config DMA channel\n");
> + dma_release_channel(nand->dma_chan);
> + return ret;
> + }
> +
> + init_completion(&nand->dma_complete);
> +
> + return 0;
> +}
> +
> +static int start_dma(struct ls1x_nand *nand, unsigned int len, bool is_write)
> +{
> + struct mtd_info *mtd = nand_to_mtd(&nand->chip);
> + struct dma_chan *chan = nand->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, nand->dma_buf, len, data_dir);
> + if (dma_mapping_error(chan->device->dev, dma_addr)) {
> + dev_err(mtd->dev.parent, "failed to map DMA buffer\n");
> + return -ENXIO;
> + }
> +
> + desc = dmaengine_prep_slave_single(chan, dma_addr, len, xfer_dir,
> + DMA_PREP_INTERRUPT);
> + if (!desc) {
> + dev_err(mtd->dev.parent,
> + "failed to prepare DMA descriptor\n");
> + ret = PTR_ERR(desc);
> + goto err;
> + }
> + desc->callback = dma_callback;
> + desc->callback_param = nand;
> +
> + nand->dma_cookie = dmaengine_submit(desc);
> + ret = dma_submit_error(nand->dma_cookie);
> + if (ret) {
> + dev_err(mtd->dev.parent,
> + "failed to submit DMA descriptor\n");
> + goto err;
> + }
> +
> + dev_dbg(mtd->dev.parent, "issue DMA with cookie=%d\n",
> + nand->dma_cookie);
> + dma_async_issue_pending(chan);
> +
> + ret = wait_for_completion_timeout(&nand->dma_complete,
> + msecs_to_jiffies(LS1X_NAND_TIMEOUT));
> + if (ret <= 0) {
> + dev_err(mtd->dev.parent, "DMA timeout\n");
> + dmaengine_terminate_all(chan);
> + ret = -EIO;
> + }
> + ret = 0;
> +err:
> + dma_unmap_single(chan->device->dev, dma_addr, len, data_dir);
> +
> + return ret;
> +}
> +
> +static void ls1x_nand_select_chip(struct mtd_info *mtd, int chip)
> +{
> +}
> +
> +static int ls1x_nand_dev_ready(struct mtd_info *mtd)
> +{
> + struct nand_chip *chip = mtd_to_nand(mtd);
> + struct ls1x_nand *nand = nand_get_controller_data(chip);
> +
> + if (nand_readl(nand, NAND_CMD) & OP_DONE)
> + return 1;
Is the OP_DONE really encoding the status of the R/B line? It seems to
me that it's only about NAND operation status. If that's the case, do
you have a way to only retrieve the R/B status?
> +
> + return 0;
> +}
> +
> +static uint8_t ls1x_nand_read_byte(struct mtd_info *mtd)
> +{
> + struct nand_chip *chip = mtd_to_nand(mtd);
> + struct ls1x_nand *nand = nand_get_controller_data(chip);
> +
> + return *(nand->data_ptr++);
> +}
> +
> +static void ls1x_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
> +{
> + struct nand_chip *chip = mtd_to_nand(mtd);
> + struct ls1x_nand *nand = nand_get_controller_data(chip);
> +
> + int real_len = min_t(size_t, len, nand->buf_len - nand->buf_off);
> +
> + memcpy(buf, nand->dma_buf + nand->buf_off, real_len);
> + nand->buf_off += real_len;
> +}
> +
> +static void ls1x_nand_write_buf(struct mtd_info *mtd, const uint8_t *buf,
> + int len)
> +{
> + struct nand_chip *chip = mtd_to_nand(mtd);
> + struct ls1x_nand *nand = nand_get_controller_data(chip);
> +
> + int real_len = min_t(size_t, len, nand->buf_len - nand->buf_off);
> +
> + memcpy(nand->dma_buf + nand->buf_off, buf, real_len);
> + nand->buf_off += real_len;
> +}
The same comment applies to {read,write}_{byte,buf}: please avoid
retrieving data from the NAND before those functions are actually
called. I don't know if what I'm asking is doable, but consider
delaying the dma_transfer until you know how many bytes are required.
If you have a PIO mode, you should consider using it instead of doing
DMA transfers.
> +
> +static inline void set_addr_len(struct mtd_info *mtd, unsigned int command,
> + int column, int page_addr)
> +{
> + struct nand_chip *chip = mtd_to_nand(mtd);
> + struct ls1x_nand *nand = nand_get_controller_data(chip);
> + int page_shift, addr_low, addr_high;
> +
> + if (command == NAND_CMD_ERASE1)
> + page_shift = chip->page_shift;
> + else
> + page_shift = chip->page_shift + 1;
> +
> + addr_low = page_addr << page_shift;
> +
> + if (column != -1) {
> + if (command == NAND_CMD_READOOB)
> + column += mtd->writesize;
> + addr_low += column;
> + nand->buf_off = 0;
> + }
> +
> + addr_high =
> + page_addr >> (sizeof(page_addr) * BITS_PER_BYTE - page_shift);
> +
> + if (command == NAND_CMD_ERASE1)
> + nand->buf_len = 1;
> + else
> + nand->buf_len = mtd->writesize + mtd->oobsize - column;
> +
> + nand_writel(nand, NAND_ADDRL, addr_low);
> + nand_writel(nand, NAND_ADDRH, addr_high);
> + nand_writel(nand, NAND_OP_NUM, nand->buf_len);
> +}
> +
> +static void ls1x_nand_cmdfunc(struct mtd_info *mtd, unsigned int command,
> + int column, int page_addr)
> +{
> + struct nand_chip *chip = mtd_to_nand(mtd);
> + struct ls1x_nand *nand = nand_get_controller_data(chip);
> +
> + dev_dbg(mtd->dev.parent, "cmd = 0x%02x, col = 0x%08x, page = 0x%08x\n",
> + command, column, page_addr);
> +
> + if (command == NAND_CMD_RNDOUT) {
> + nand->buf_off = column;
> + return;
> + }
> +
> + /*set address, buffer length and buffer offset */
> + if (column != -1 || page_addr != -1)
> + set_addr_len(mtd, command, column, page_addr);
> +
> + /*prepare NAND command */
> + switch (command) {
> + case NAND_CMD_RESET:
> + nand->cmd_val = CMD_RESET;
> + break;
> + case NAND_CMD_STATUS:
> + nand->cmd_val = CMD_STATUS;
> + break;
> + case NAND_CMD_READID:
> + nand->cmd_val = CMD_READID;
> + break;
> + case NAND_CMD_READ0:
> + nand->cmd_val = OP_SPARE | OP_MAIN | CMD_READ;
> + break;
> + case NAND_CMD_READOOB:
> + nand->cmd_val = OP_SPARE | CMD_READ;
> + break;
> + case NAND_CMD_ERASE1:
> + nand->cmd_val = CMD_ERASE;
> + break;
> + case NAND_CMD_PAGEPROG:
> + break;
> + case NAND_CMD_SEQIN:
> + if (column < mtd->writesize)
> + nand->cmd_val = OP_SPARE | OP_MAIN | CMD_WRITE;
> + else
> + nand->cmd_val = OP_SPARE | CMD_WRITE;
> + default:
> + return;
> + }
> +
> + /*set NAND command */
> + set_cmd(nand, nand->cmd_val);
> + /*trigger NAND operation */
> + start_nand(nand);
> + /*trigger DMA for R/W operation */
> + if (command == NAND_CMD_READ0 || command == NAND_CMD_READOOB)
> + start_dma(nand, nand->buf_len, false);
> + else if (command == NAND_CMD_PAGEPROG)
> + start_dma(nand, nand->buf_len, true);
> + nand_wait_ready(mtd);
> +
> + if (command == NAND_CMD_STATUS) {
> + nand->datareg[0] = (char)(nand_readl(nand, NAND_STATUS) >> 8);
> + /*work around hardware bug for invalid STATUS */
> + nand->datareg[0] |= 0xc0;
> + nand->data_ptr = nand->datareg;
> + } else if (command == NAND_CMD_READID) {
> + nand->datareg[0] = (char)(nand_readl(nand, NAND_IDH));
> + nand->datareg[1] = (char)(nand_readl(nand, NAND_IDL) >> 24);
> + nand->datareg[2] = (char)(nand_readl(nand, NAND_IDL) >> 16);
> + nand->datareg[3] = (char)(nand_readl(nand, NAND_IDL) >> 8);
> + nand->datareg[4] = (char)(nand_readl(nand, NAND_IDL));
> + nand->data_ptr = nand->datareg;
> + }
I hate those controllers trying to automate some basic operations like
RESET, READID or STATUS. Do you have a way to send raw CMD and ADDR
cycles (BTW, do you have a public datasheet for this IP?)?
There's a real reason to avoid those custom ->cmdfunc()
implementations: each time we want to add generic support for a new
NAND command, we have to patch all those custom implementations.
BTW, I see that you don't support the NAND_CMD_PARAM and
NAND_CMD_{SET,GET}_FEATURES commands, which are mandatory if you want
to interface with ONFI NANDs.
Best Regards,
Boris
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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