From: Kelvin Cheung <keguang.zh...@gmail.com>

This patch adds NAND driver for Loongson1B.

Signed-off-by: Kelvin Cheung <keguang.zh...@gmail.com>

---
v3:
   Replace __raw_readl/__raw_writel with readl/writel.
   Split ls1x_nand into two structures: ls1x_nand_chip and ls1x_nand_controller.
V2:
   Modify the dependency in Kconfig due to the changes of DMA module.
---
 drivers/mtd/nand/Kconfig          |   8 +
 drivers/mtd/nand/Makefile         |   1 +
 drivers/mtd/nand/loongson1_nand.c | 555 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 564 insertions(+)
 create mode 100644 drivers/mtd/nand/loongson1_nand.c

diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index f05e0e9..be20fb8 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 LOONGSON1_DMA
+       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..86831773
--- /dev/null
+++ b/drivers/mtd/nand/loongson1_nand.c
@@ -0,0 +1,555 @@
+/*
+ * NAND Flash Driver for Loongson 1 SoC
+ *
+ * Copyright (C) 2015-2016 Zhang, Keguang <keguang.zh...@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(nandc, off)         \
+       readl((nandc)->reg_base + (off))
+
+#define nand_writel(nandc, off, val)   \
+       writel((val), (nandc)->reg_base + (off))
+
+#define set_cmd(nandc, ctrl)           \
+       nand_writel(nandc, NAND_CMD, ctrl)
+
+#define start_nand(nandc)              \
+       nand_writel(nandc, NAND_CMD, nand_readl(nandc, NAND_CMD) | CMD_VALID)
+
+struct ls1x_nand_chip {
+       struct nand_chip chip;
+       struct plat_ls1x_nand *pdata;
+};
+
+struct ls1x_nand_controller {
+       struct clk *clk;
+       void __iomem *reg_base;
+
+       int cmd_ctrl;
+       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;
+};
+
+static inline struct ls1x_nand_chip *to_ls1x_nand_chip(struct mtd_info *mtd)
+{
+       return container_of(mtd_to_nand(mtd), struct ls1x_nand_chip, chip);
+}
+
+static void dma_callback(void *data)
+{
+       struct mtd_info *mtd = (struct mtd_info *)data;
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct ls1x_nand_controller *nandc = nand_get_controller_data(chip);
+       struct dma_tx_state state;
+       enum dma_status status;
+
+       status =
+           dmaengine_tx_status(nandc->dma_chan, nandc->dma_cookie, &state);
+       if (likely(status == DMA_COMPLETE))
+               dev_dbg(mtd->dev.parent, "DMA complete with cookie=%d\n",
+                       nandc->dma_cookie);
+       else
+               dev_err(mtd->dev.parent, "DMA error with cookie=%d\n",
+                       nandc->dma_cookie);
+
+       complete(&nandc->dma_complete);
+}
+
+static int setup_dma(struct mtd_info *mtd)
+{
+       struct ls1x_nand_chip *nand = to_ls1x_nand_chip(mtd);
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct ls1x_nand_controller *nandc = nand_get_controller_data(chip);
+       struct dma_slave_config cfg;
+       dma_cap_mask_t mask;
+       int ret;
+
+       if (!nand->pdata->dma_filter) {
+               dev_err(mtd->dev.parent, "no DMA filter\n");
+               return -ENOENT;
+       }
+
+       /* allocate DMA buffer */
+       nandc->dma_buf = devm_kzalloc(mtd->dev.parent,
+                                     mtd->writesize + mtd->oobsize,
+                                     GFP_KERNEL);
+       if (!nandc->dma_buf)
+               return -ENOMEM;
+
+       dma_cap_zero(mask);
+       dma_cap_set(DMA_SLAVE, mask);
+       nandc->dma_chan = dma_request_channel(mask, nand->pdata->dma_filter,
+                                             &nandc->dma_chan_id);
+       if (!nandc->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(nandc->dma_chan), dev_name(mtd->dev.parent));
+
+       cfg.src_addr = CPHYSADDR(nandc->reg_base + NAND_DMA_ADDR);
+       cfg.dst_addr = CPHYSADDR(nandc->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(nandc->dma_chan, &cfg);
+       if (ret) {
+               dev_err(mtd->dev.parent, "failed to config DMA channel\n");
+               dma_release_channel(nandc->dma_chan);
+               return ret;
+       }
+
+       init_completion(&nandc->dma_complete);
+
+       return 0;
+}
+
+static int start_dma(struct mtd_info *mtd, unsigned int len, bool is_write)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct ls1x_nand_controller *nandc = nand_get_controller_data(chip);
+       struct dma_chan *chan = nandc->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, nandc->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 = mtd;
+
+       nandc->dma_cookie = dmaengine_submit(desc);
+       ret = dma_submit_error(nandc->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",
+               nandc->dma_cookie);
+       dma_async_issue_pending(chan);
+
+       ret = wait_for_completion_timeout(&nandc->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_controller *nandc = nand_get_controller_data(chip);
+
+       if (nand_readl(nandc, NAND_CMD) & OP_DONE)
+               return 1;
+
+       return 0;
+}
+
+static uint8_t ls1x_nand_read_byte(struct mtd_info *mtd)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct ls1x_nand_controller *nandc = nand_get_controller_data(chip);
+
+       return *(nandc->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_controller *nandc = nand_get_controller_data(chip);
+
+       int real_len = min_t(size_t, len, nandc->buf_len - nandc->buf_off);
+
+       memcpy(buf, nandc->dma_buf + nandc->buf_off, real_len);
+       nandc->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_controller *nandc = nand_get_controller_data(chip);
+
+       int real_len = min_t(size_t, len, nandc->buf_len - nandc->buf_off);
+
+       memcpy(nandc->dma_buf + nandc->buf_off, buf, real_len);
+       nandc->buf_off += real_len;
+}
+
+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_controller *nandc = 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;
+               nandc->buf_off = 0;
+       }
+
+       addr_high =
+           page_addr >> (sizeof(page_addr) * BITS_PER_BYTE - page_shift);
+
+       if (command == NAND_CMD_ERASE1)
+               nandc->buf_len = 1;
+       else
+               nandc->buf_len = mtd->writesize + mtd->oobsize - column;
+
+       nand_writel(nandc, NAND_ADDRL, addr_low);
+       nand_writel(nandc, NAND_ADDRH, addr_high);
+       nand_writel(nandc, NAND_OP_NUM, nandc->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_controller *nandc = 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) {
+               nandc->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:
+               nandc->cmd_ctrl = CMD_RESET;
+               break;
+       case NAND_CMD_STATUS:
+               nandc->cmd_ctrl = CMD_STATUS;
+               break;
+       case NAND_CMD_READID:
+               nandc->cmd_ctrl = CMD_READID;
+               break;
+       case NAND_CMD_READ0:
+               nandc->cmd_ctrl = OP_SPARE | OP_MAIN | CMD_READ;
+               break;
+       case NAND_CMD_READOOB:
+               nandc->cmd_ctrl = OP_SPARE | CMD_READ;
+               break;
+       case NAND_CMD_ERASE1:
+               nandc->cmd_ctrl = CMD_ERASE;
+               break;
+       case NAND_CMD_PAGEPROG:
+               break;
+       case NAND_CMD_SEQIN:
+               if (column < mtd->writesize)
+                       nandc->cmd_ctrl = OP_SPARE | OP_MAIN | CMD_WRITE;
+               else
+                       nandc->cmd_ctrl = OP_SPARE | CMD_WRITE;
+       default:
+               return;
+       }
+
+       /*set NAND command */
+       set_cmd(nandc, nandc->cmd_ctrl);
+       /*trigger NAND operation */
+       start_nand(nandc);
+       /*trigger DMA for R/W operation */
+       if (command == NAND_CMD_READ0 || command == NAND_CMD_READOOB)
+               start_dma(mtd, nandc->buf_len, false);
+       else if (command == NAND_CMD_PAGEPROG)
+               start_dma(mtd, nandc->buf_len, true);
+       nand_wait_ready(mtd);
+
+       if (command == NAND_CMD_STATUS) {
+               nandc->datareg[0] = (char)(nand_readl(nandc, NAND_STATUS) >> 8);
+               /*work around hardware bug for invalid STATUS */
+               nandc->datareg[0] |= 0xc0;
+               nandc->data_ptr = nandc->datareg;
+       } else if (command == NAND_CMD_READID) {
+               nandc->datareg[0] = (char)(nand_readl(nandc, NAND_IDH));
+               nandc->datareg[1] = (char)(nand_readl(nandc, NAND_IDL) >> 24);
+               nandc->datareg[2] = (char)(nand_readl(nandc, NAND_IDL) >> 16);
+               nandc->datareg[3] = (char)(nand_readl(nandc, NAND_IDL) >> 8);
+               nandc->datareg[4] = (char)(nand_readl(nandc, NAND_IDL));
+               nandc->data_ptr = nandc->datareg;
+       }
+
+       nandc->cmd_ctrl = 0;
+}
+
+static void ls1x_nand_hw_init(struct mtd_info *mtd, int hold_cycle,
+                             int wait_cycle)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct ls1x_nand_controller *nandc = nand_get_controller_data(chip);
+       int chipsize = (int)(chip->chipsize >> 20);
+       int cell_size = 0x0;
+
+       switch (chipsize) {
+       case SZ_128:            /*128M */
+               cell_size = 0x0;
+               break;
+       case SZ_256:            /*256M */
+               cell_size = 0x1;
+               break;
+       case SZ_512:            /*512M */
+               cell_size = 0x2;
+               break;
+       case SZ_1K:             /*1G */
+               cell_size = 0x3;
+               break;
+       case SZ_2K:             /*2G */
+               cell_size = 0x4;
+               break;
+       case SZ_4K:             /*4G */
+               cell_size = 0x5;
+               break;
+       case SZ_8K:             /*8G */
+               cell_size = 0x6;
+               break;
+       case SZ_16K:            /*16G */
+               cell_size = 0x7;
+               break;
+       default:
+               dev_warn(mtd->dev.parent, "unsupported chip size: %d MB\n",
+                        chipsize);
+       }
+
+       nand_writel(nandc, NAND_TIMING, (hold_cycle << 8) | wait_cycle);
+       nand_writel(nandc, NAND_PARAM,
+                   (nand_readl(nandc, NAND_PARAM) & 0xfffff0ff) | (cell_size <<
+                                                                   8));
+}
+
+static int ls1x_nand_init(struct platform_device *pdev,
+                         struct ls1x_nand_controller *nandc)
+{
+       struct device *dev = &pdev->dev;
+       struct ls1x_nand_chip *nand;
+       struct plat_ls1x_nand *pdata;
+       struct nand_chip *chip;
+       struct mtd_info *mtd;
+       int ret = 0;
+
+       nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
+       if (!nand)
+               return -ENOMEM;
+
+       pdata = dev_get_platdata(dev);
+       if (!pdata) {
+               dev_err(dev, "platform data missing\n");
+               return -EINVAL;
+       }
+       nand->pdata = pdata;
+
+       chip = &nand->chip;
+       chip->read_byte         = ls1x_nand_read_byte;
+       chip->read_buf          = ls1x_nand_read_buf;
+       chip->write_buf         = ls1x_nand_write_buf;
+       chip->select_chip       = ls1x_nand_select_chip;
+       chip->dev_ready         = ls1x_nand_dev_ready;
+       chip->cmdfunc           = ls1x_nand_cmdfunc;
+       chip->options           = NAND_NO_SUBPAGE_WRITE;
+       chip->ecc.mode          = NAND_ECC_SOFT;
+       nand_set_controller_data(chip, nandc);
+
+       mtd = nand_to_mtd(chip);
+       mtd->name = "ls1x-nand";
+       mtd->owner = THIS_MODULE;
+       mtd->dev.parent = dev;
+
+       ret = nand_scan_ident(mtd, 1, NULL);
+       if (ret)
+               return ret;
+
+       ls1x_nand_hw_init(mtd, pdata->hold_cycle, pdata->wait_cycle);
+
+       ret = setup_dma(mtd);
+       if (ret)
+               return ret;
+
+       ret = nand_scan_tail(mtd);
+       if (ret) {
+               dma_release_channel(nandc->dma_chan);
+               return ret;
+       }
+
+       ret = mtd_device_register(mtd, pdata->parts, pdata->nr_parts);
+       if (ret) {
+               dev_err(dev, "failed to register MTD device: %d\n", ret);
+               dma_release_channel(nandc->dma_chan);
+       }
+
+       platform_set_drvdata(pdev, mtd);
+       return ret;
+}
+
+static int ls1x_nand_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct ls1x_nand_controller *nandc;
+       struct resource *res;
+       int ret;
+
+       nandc = devm_kzalloc(dev, sizeof(*nandc), GFP_KERNEL);
+       if (!nandc)
+               return -ENOMEM;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res) {
+               dev_err(dev, "failed to get I/O memory\n");
+               return -ENXIO;
+       }
+
+       nandc->reg_base = devm_ioremap_resource(dev, res);
+       if (IS_ERR(nandc->reg_base))
+               return PTR_ERR(nandc->reg_base);
+
+       res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
+       if (!res) {
+               dev_err(dev, "failed to get DMA information\n");
+               return -ENXIO;
+       }
+       nandc->dma_chan_id = res->start;
+
+       nandc->clk = devm_clk_get(dev, pdev->name);
+       if (IS_ERR(nandc->clk)) {
+               dev_err(dev, "failed to get %s clock\n", pdev->name);
+               return PTR_ERR(nandc->clk);
+       }
+       clk_prepare_enable(nandc->clk);
+
+       ret = ls1x_nand_init(pdev, nandc);
+       if (ret) {
+               clk_disable_unprepare(nandc->clk);
+               return ret;
+       }
+
+       dev_info(dev, "Loongson1 NAND driver registered\n");
+       return 0;
+}
+
+static int ls1x_nand_remove(struct platform_device *pdev)
+{
+       struct mtd_info *mtd = platform_get_drvdata(pdev);
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct ls1x_nand_controller *nandc = nand_get_controller_data(chip);
+
+       if (nandc->dma_chan)
+               dma_release_channel(nandc->dma_chan);
+       nand_release(mtd);
+       clk_disable_unprepare(nandc->clk);
+
+       return 0;
+}
+
+static struct platform_driver ls1x_nand_driver = {
+       .probe  = ls1x_nand_probe,
+       .remove = ls1x_nand_remove,
+       .driver = {
+               .name   = "ls1x-nand",
+               .owner  = THIS_MODULE,
+       },
+};
+
+module_platform_driver(ls1x_nand_driver);
+
+MODULE_AUTHOR("Kelvin Cheung <keguang.zh...@gmail.com>");
+MODULE_DESCRIPTION("Loongson1 NAND Flash driver");
+MODULE_LICENSE("GPL");
-- 
1.9.1

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