--- linux-4.9.37/drivers/mtd/nand/gkfmc100/fmc100_os.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-4.9.y/drivers/mtd/nand/gkfmc100/fmc100_os.c	2021-06-07 13:01:33.000000000 +0300
@@ -0,0 +1,223 @@
+/*
+ * Copyright (c) Hunan Goke,Chengdu Goke,Shandong Goke. 2021. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+#include <linux/of_platform.h>
+#include <asm/setup.h>
+
+#include "../../mtdcore.h"
+#include "fmc100.h"
+
+/*****************************************************************************/
+static int fmc100_spi_nand_pre_probe(struct nand_chip *chip)
+{
+	uint8_t nand_maf_id;
+	struct fmc_host *host = chip->priv;
+
+	/* Reset the chip first */
+	host->send_cmd_reset(host);
+	udelay(1000);
+
+	/* Check the ID */
+	host->offset = 0;
+	memset((unsigned char *)(chip->IO_ADDR_R), 0, 0x10);
+	host->send_cmd_readid(host);
+	nand_maf_id = fmc_readb(chip->IO_ADDR_R);
+
+	if (nand_maf_id == 0x00 || nand_maf_id == 0xff) {
+		printk("Cannot found a valid SPI Nand Device\n");
+		return 1;
+	}
+
+	return 0;
+}
+/*****************************************************************************/
+static int fmc_nand_scan(struct mtd_info *mtd)
+{
+	int result = 0;
+	unsigned char cs, chip_num = CONFIG_SPI_NAND_MAX_CHIP_NUM;
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct fmc_host *host = chip->priv;
+
+	for (cs = 0; chip_num && (cs < FMC_MAX_CHIP_NUM); cs++) {
+		if (fmc_cs_user[cs]) {
+			FMC_PR(BT_DBG, "\t\t*-Current CS(%d) is occupied.\n",
+			       cs);
+			continue;
+		}
+
+		host->cmd_op.cs = cs;
+
+		if (fmc100_spi_nand_pre_probe(chip)) {
+			return -ENODEV;
+		}
+
+		FMC_PR(BT_DBG, "\t\t*-Scan SPI nand flash on CS: %d\n", cs);
+		if (nand_scan(mtd, chip_num)) {
+			continue;
+		}
+		chip_num--;
+	}
+
+	if (chip_num == CONFIG_SPI_NAND_MAX_CHIP_NUM) {
+		result = -ENXIO;
+	} else {
+		result = 0;
+	}
+
+	return result;
+}
+
+/*****************************************************************************/
+static int bsp_spi_nand_probe(struct platform_device *pltdev)
+{
+	int len, result = 0;
+	struct fmc_host *host = NULL;
+	struct nand_chip *chip = NULL;
+	struct mtd_info *mtd = NULL;
+	struct device *dev = &pltdev->dev;
+	struct device_node *np = NULL;
+	struct bsp_fmc *fmc = dev_get_drvdata(dev->parent);
+
+	FMC_PR(BT_DBG, "\t*-Start SPI Nand flash driver probe\n");
+
+	if (!fmc) {
+		dev_err(dev, "get mfd fmc devices failed\n");
+		return -ENXIO;
+	}
+
+	len = sizeof(struct fmc_host) + sizeof(struct nand_chip)
+	      + sizeof(struct mtd_info);
+	host = devm_kzalloc(dev, len, GFP_KERNEL);
+	if (!host) {
+		return -ENOMEM;
+	}
+	memset((char *)host, 0, len);
+
+	platform_set_drvdata(pltdev, host);
+	host->dev = &pltdev->dev;
+
+	host->chip = chip = (struct nand_chip *)&host[1];
+	host->mtd  = mtd  = nand_to_mtd(chip);
+
+	host->regbase = fmc->regbase;
+	host->iobase = fmc->iobase;
+	host->clk = fmc->clk;
+	host->lock = &fmc->lock;
+	host->buffer = fmc->buffer;
+	host->dma_buffer = fmc->dma_buffer;
+
+	memset((char *)host->iobase, 0xff, fmc->dma_len);
+	chip->IO_ADDR_R = chip->IO_ADDR_W = host->iobase;
+
+	chip->priv = host;
+	result = fmc100_spi_nand_init(chip);
+	if (result) {
+		FMC_PR(BT_DBG, "\t|-SPI Nand init failed, ret: %d\n", result);
+		result = -ENODEV;
+		goto fail;
+	}
+
+	np = of_get_next_available_child(dev->of_node, NULL);
+	mtd->name = np->name;
+	mtd->type = MTD_NANDFLASH;
+	mtd->priv = chip;
+	mtd->owner = THIS_MODULE;
+
+	result = of_property_read_u32(np, "spi-max-frequency", &host->clkrate);
+	if (result) {
+		goto fail;
+	}
+
+	result = fmc_nand_scan(mtd);
+	if (result) {
+		FMC_PR(BT_DBG, "\t|-Scan SPI Nand failed.\n");
+		goto fail;
+	}
+
+	result = mtd_device_register(mtd, NULL, 0);
+	if (!result) {
+		FMC_PR(BT_DBG, "\t*-End driver probe !!\n");
+		return 0;
+	}
+
+	result = -ENODEV;
+fail:
+	clk_disable_unprepare(host->clk);
+	nand_release(mtd);
+
+	DB_MSG("Error: driver probe, result: %d\n", result);
+	return result;
+}
+
+/*****************************************************************************/
+static int bsp_spi_nand_remove(struct platform_device *pltdev)
+{
+	struct fmc_host *host = platform_get_drvdata(pltdev);
+	if (host == NULL){
+		FMC_PR(BT_DBG, "\t*host is NULL ,remove err !!\n");
+		return 0;
+	}
+	clk_disable_unprepare(host->clk);
+	nand_release(host->mtd);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+/*****************************************************************************/
+static int fmc100_os_suspend(struct platform_device *pltdev,
+			       pm_message_t state)
+{
+	struct fmc_host *host = platform_get_drvdata(pltdev);
+
+	if (host && host->suspend) {
+		return (host->suspend)(pltdev, state);
+	}
+
+	return 0;
+}
+
+/*****************************************************************************/
+static int fmc100_os_resume(struct platform_device *pltdev)
+{
+	struct fmc_host *host = platform_get_drvdata(pltdev);
+
+	if (host && host->resume) {
+		return (host->resume)(pltdev);
+	}
+
+	return 0;
+}
+#endif /* End of CONFIG_PM */
+/*****************************************************************************/
+static const struct of_device_id bsp_spi_nand_dt_ids[] = {
+	{ .compatible = "goke,fmc-spi-nand"},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, bsp_spi_nand_dt_ids);
+
+static struct platform_driver bsp_spi_nand_driver = {
+	.driver = {
+		.name   = "bsp_spi_nand",
+		.of_match_table = bsp_spi_nand_dt_ids,
+	},
+	.probe  = bsp_spi_nand_probe,
+	.remove = bsp_spi_nand_remove,
+#ifdef CONFIG_PM
+	.suspend    = fmc100_os_suspend,
+	.resume     = fmc100_os_resume,
+#endif
+};
+module_platform_driver(bsp_spi_nand_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Goke Flash Memory Controller V100 SPI Nand Driver");