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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright © 2008 Ilya Yanok, Emcraft Systems
*/
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/partitions.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/io.h>
#define FPGA_NAND_CMD_MASK (0x7 << 28)
#define FPGA_NAND_CMD_COMMAND (0x0 << 28)
#define FPGA_NAND_CMD_ADDR (0x1 << 28)
#define FPGA_NAND_CMD_READ (0x2 << 28)
#define FPGA_NAND_CMD_WRITE (0x3 << 28)
#define FPGA_NAND_BUSY (0x1 << 15)
#define FPGA_NAND_ENABLE (0x1 << 31)
#define FPGA_NAND_DATA_SHIFT 16
struct socrates_nand_host {
struct nand_chip nand_chip;
void __iomem *io_base;
struct device *dev;
};
/**
* socrates_nand_write_buf - write buffer to chip
* @this: NAND chip object
* @buf: data buffer
* @len: number of bytes to write
*/
static void socrates_nand_write_buf(struct nand_chip *this, const uint8_t *buf,
int len)
{
int i;
struct socrates_nand_host *host = nand_get_controller_data(this);
for (i = 0; i < len; i++) {
out_be32(host->io_base, FPGA_NAND_ENABLE |
FPGA_NAND_CMD_WRITE |
(buf[i] << FPGA_NAND_DATA_SHIFT));
}
}
/**
* socrates_nand_read_buf - read chip data into buffer
* @this: NAND chip object
* @buf: buffer to store date
* @len: number of bytes to read
*/
static void socrates_nand_read_buf(struct nand_chip *this, uint8_t *buf,
int len)
{
int i;
struct socrates_nand_host *host = nand_get_controller_data(this);
uint32_t val;
val = FPGA_NAND_ENABLE | FPGA_NAND_CMD_READ;
out_be32(host->io_base, val);
for (i = 0; i < len; i++) {
buf[i] = (in_be32(host->io_base) >>
FPGA_NAND_DATA_SHIFT) & 0xff;
}
}
/**
* socrates_nand_read_byte - read one byte from the chip
* @mtd: MTD device structure
*/
static uint8_t socrates_nand_read_byte(struct nand_chip *this)
{
uint8_t byte;
socrates_nand_read_buf(this, &byte, sizeof(byte));
return byte;
}
/*
* Hardware specific access to control-lines
*/
static void socrates_nand_cmd_ctrl(struct nand_chip *nand_chip, int cmd,
unsigned int ctrl)
{
struct socrates_nand_host *host = nand_get_controller_data(nand_chip);
uint32_t val;
if (cmd == NAND_CMD_NONE)
return;
if (ctrl & NAND_CLE)
val = FPGA_NAND_CMD_COMMAND;
else
val = FPGA_NAND_CMD_ADDR;
if (ctrl & NAND_NCE)
val |= FPGA_NAND_ENABLE;
val |= (cmd & 0xff) << FPGA_NAND_DATA_SHIFT;
out_be32(host->io_base, val);
}
/*
* Read the Device Ready pin.
*/
static int socrates_nand_device_ready(struct nand_chip *nand_chip)
{
struct socrates_nand_host *host = nand_get_controller_data(nand_chip);
if (in_be32(host->io_base) & FPGA_NAND_BUSY)
return 0; /* busy */
return 1;
}
/*
* Probe for the NAND device.
*/
static int socrates_nand_probe(struct platform_device *ofdev)
{
struct socrates_nand_host *host;
struct mtd_info *mtd;
struct nand_chip *nand_chip;
int res;
/* Allocate memory for the device structure (and zero it) */
host = devm_kzalloc(&ofdev->dev, sizeof(*host), GFP_KERNEL);
if (!host)
return -ENOMEM;
host->io_base = of_iomap(ofdev->dev.of_node, 0);
if (host->io_base == NULL) {
dev_err(&ofdev->dev, "ioremap failed\n");
return -EIO;
}
nand_chip = &host->nand_chip;
mtd = nand_to_mtd(nand_chip);
host->dev = &ofdev->dev;
/* link the private data structures */
nand_set_controller_data(nand_chip, host);
nand_set_flash_node(nand_chip, ofdev->dev.of_node);
mtd->name = "socrates_nand";
mtd->dev.parent = &ofdev->dev;
nand_chip->legacy.cmd_ctrl = socrates_nand_cmd_ctrl;
nand_chip->legacy.read_byte = socrates_nand_read_byte;
nand_chip->legacy.write_buf = socrates_nand_write_buf;
nand_chip->legacy.read_buf = socrates_nand_read_buf;
nand_chip->legacy.dev_ready = socrates_nand_device_ready;
nand_chip->ecc.mode = NAND_ECC_SOFT; /* enable ECC */
nand_chip->ecc.algo = NAND_ECC_HAMMING;
/* TODO: I have no idea what real delay is. */
nand_chip->legacy.chip_delay = 20; /* 20us command delay time */
dev_set_drvdata(&ofdev->dev, host);
res = nand_scan(nand_chip, 1);
if (res)
goto out;
res = mtd_device_register(mtd, NULL, 0);
if (!res)
return res;
nand_release(nand_chip);
out:
iounmap(host->io_base);
return res;
}
/*
* Remove a NAND device.
*/
static int socrates_nand_remove(struct platform_device *ofdev)
{
struct socrates_nand_host *host = dev_get_drvdata(&ofdev->dev);
nand_release(&host->nand_chip);
iounmap(host->io_base);
return 0;
}
static const struct of_device_id socrates_nand_match[] =
{
{
.compatible = "abb,socrates-nand",
},
{},
};
MODULE_DEVICE_TABLE(of, socrates_nand_match);
static struct platform_driver socrates_nand_driver = {
.driver = {
.name = "socrates_nand",
.of_match_table = socrates_nand_match,
},
.probe = socrates_nand_probe,
.remove = socrates_nand_remove,
};
module_platform_driver(socrates_nand_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ilya Yanok");
MODULE_DESCRIPTION("NAND driver for Socrates board");
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