linux/drivers/mtd/nand/raw/gpio.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Updated, and converted to generic GPIO based driver by Russell King.
 *
 * Written by Ben Dooks <[email protected]>
 *   Based on 2.4 version by Mark Whittaker
 *
 * © 2004 Simtec Electronics
 *
 * Device driver for NAND flash that uses a memory mapped interface to
 * read/write the NAND commands and data, and GPIO pins for control signals
 * (the DT binding refers to this as "GPIO assisted NAND flash")
 */

#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/gpio/consumer.h>
#include <linux/io.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/nand-gpio.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/delay.h>

struct gpiomtd { … };

static inline struct gpiomtd *gpio_nand_getpriv(struct mtd_info *mtd)
{ … }


#ifdef CONFIG_ARM
/* gpio_nand_dosync()
 *
 * Make sure the GPIO state changes occur in-order with writes to NAND
 * memory region.
 * Needed on PXA due to bus-reordering within the SoC itself (see section on
 * I/O ordering in PXA manual (section 2.3, p35)
 */
static void gpio_nand_dosync(struct gpiomtd *gpiomtd)
{
	unsigned long tmp;

	if (gpiomtd->io_sync) {
		/*
		 * Linux memory barriers don't cater for what's required here.
		 * What's required is what's here - a read from a separate
		 * region with a dependency on that read.
		 */
		tmp = readl(gpiomtd->io_sync);
		asm volatile("mov %1, %0\n" : "=r" (tmp) : "r" (tmp));
	}
}
#else
static inline void gpio_nand_dosync(struct gpiomtd *gpiomtd) { … }
#endif

static int gpio_nand_exec_instr(struct nand_chip *chip,
				const struct nand_op_instr *instr)
{ … }

static int gpio_nand_exec_op(struct nand_chip *chip,
			     const struct nand_operation *op,
			     bool check_only)
{ … }

static int gpio_nand_attach_chip(struct nand_chip *chip)
{ … }

static const struct nand_controller_ops gpio_nand_ops = …;

#ifdef CONFIG_OF
static const struct of_device_id gpio_nand_id_table[] = …;
MODULE_DEVICE_TABLE(of, gpio_nand_id_table);

static int gpio_nand_get_config_of(const struct device *dev,
				   struct gpio_nand_platdata *plat)
{ … }

static struct resource *gpio_nand_get_io_sync_of(struct platform_device *pdev)
{ … }
#else /* CONFIG_OF */
static inline int gpio_nand_get_config_of(const struct device *dev,
					  struct gpio_nand_platdata *plat)
{
	return -ENOSYS;
}

static inline struct resource *
gpio_nand_get_io_sync_of(struct platform_device *pdev)
{
	return NULL;
}
#endif /* CONFIG_OF */

static inline int gpio_nand_get_config(const struct device *dev,
				       struct gpio_nand_platdata *plat)
{ … }

static inline struct resource *
gpio_nand_get_io_sync(struct platform_device *pdev)
{ … }

static void gpio_nand_remove(struct platform_device *pdev)
{ … }

static int gpio_nand_probe(struct platform_device *pdev)
{ … }

static struct platform_driver gpio_nand_driver = …;

module_platform_driver(…) …;

MODULE_LICENSE(…) …;
MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;