linux_dsm_epyc7002/drivers/mtd/devices/mchp23k256.c
Chris Packham 4379075a87 mtd: mchp23k256: Add support for mchp23lcv1024
The mchp23lcv1024 is similar to the mchp23k256, the differences (from a
software point of view) are the capacity of the chip and the size of the
addresses used.

There is no way to detect the specific chip so we must be told via a
Device Tree or default to mchp23k256 when device tree is not used.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
2017-06-08 16:32:11 -07:00

237 lines
5.5 KiB
C

/*
* mchp23k256.c
*
* Driver for Microchip 23k256 SPI RAM chips
*
* Copyright © 2016 Andrew Lunn <andrew@lunn.ch>
*
* This code is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/sizes.h>
#include <linux/spi/flash.h>
#include <linux/spi/spi.h>
#include <linux/of_device.h>
#define MAX_CMD_SIZE 4
struct mchp23_caps {
u8 addr_width;
unsigned int size;
};
struct mchp23k256_flash {
struct spi_device *spi;
struct mutex lock;
struct mtd_info mtd;
const struct mchp23_caps *caps;
};
#define MCHP23K256_CMD_WRITE_STATUS 0x01
#define MCHP23K256_CMD_WRITE 0x02
#define MCHP23K256_CMD_READ 0x03
#define MCHP23K256_MODE_SEQ BIT(6)
#define to_mchp23k256_flash(x) container_of(x, struct mchp23k256_flash, mtd)
static void mchp23k256_addr2cmd(struct mchp23k256_flash *flash,
unsigned int addr, u8 *cmd)
{
int i;
/*
* Address is sent in big endian (MSB first) and we skip
* the first entry of the cmd array which contains the cmd
* opcode.
*/
for (i = flash->caps->addr_width; i > 0; i--, addr >>= 8)
cmd[i] = addr;
}
static int mchp23k256_cmdsz(struct mchp23k256_flash *flash)
{
return 1 + flash->caps->addr_width;
}
static int mchp23k256_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const unsigned char *buf)
{
struct mchp23k256_flash *flash = to_mchp23k256_flash(mtd);
struct spi_transfer transfer[2] = {};
struct spi_message message;
unsigned char command[MAX_CMD_SIZE];
spi_message_init(&message);
command[0] = MCHP23K256_CMD_WRITE;
mchp23k256_addr2cmd(flash, to, command);
transfer[0].tx_buf = command;
transfer[0].len = mchp23k256_cmdsz(flash);
spi_message_add_tail(&transfer[0], &message);
transfer[1].tx_buf = buf;
transfer[1].len = len;
spi_message_add_tail(&transfer[1], &message);
mutex_lock(&flash->lock);
spi_sync(flash->spi, &message);
if (retlen && message.actual_length > sizeof(command))
*retlen += message.actual_length - sizeof(command);
mutex_unlock(&flash->lock);
return 0;
}
static int mchp23k256_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, unsigned char *buf)
{
struct mchp23k256_flash *flash = to_mchp23k256_flash(mtd);
struct spi_transfer transfer[2] = {};
struct spi_message message;
unsigned char command[MAX_CMD_SIZE];
spi_message_init(&message);
memset(&transfer, 0, sizeof(transfer));
command[0] = MCHP23K256_CMD_READ;
mchp23k256_addr2cmd(flash, from, command);
transfer[0].tx_buf = command;
transfer[0].len = mchp23k256_cmdsz(flash);
spi_message_add_tail(&transfer[0], &message);
transfer[1].rx_buf = buf;
transfer[1].len = len;
spi_message_add_tail(&transfer[1], &message);
mutex_lock(&flash->lock);
spi_sync(flash->spi, &message);
if (retlen && message.actual_length > sizeof(command))
*retlen += message.actual_length - sizeof(command);
mutex_unlock(&flash->lock);
return 0;
}
/*
* Set the device into sequential mode. This allows read/writes to the
* entire SRAM in a single operation
*/
static int mchp23k256_set_mode(struct spi_device *spi)
{
struct spi_transfer transfer = {};
struct spi_message message;
unsigned char command[2];
spi_message_init(&message);
command[0] = MCHP23K256_CMD_WRITE_STATUS;
command[1] = MCHP23K256_MODE_SEQ;
transfer.tx_buf = command;
transfer.len = sizeof(command);
spi_message_add_tail(&transfer, &message);
return spi_sync(spi, &message);
}
static const struct mchp23_caps mchp23k256_caps = {
.size = SZ_32K,
.addr_width = 2,
};
static const struct mchp23_caps mchp23lcv1024_caps = {
.size = SZ_128K,
.addr_width = 3,
};
static int mchp23k256_probe(struct spi_device *spi)
{
struct mchp23k256_flash *flash;
struct flash_platform_data *data;
int err;
flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL);
if (!flash)
return -ENOMEM;
flash->spi = spi;
mutex_init(&flash->lock);
spi_set_drvdata(spi, flash);
err = mchp23k256_set_mode(spi);
if (err)
return err;
data = dev_get_platdata(&spi->dev);
flash->caps = of_device_get_match_data(&spi->dev);
if (!flash->caps)
flash->caps = &mchp23k256_caps;
mtd_set_of_node(&flash->mtd, spi->dev.of_node);
flash->mtd.dev.parent = &spi->dev;
flash->mtd.type = MTD_RAM;
flash->mtd.flags = MTD_CAP_RAM;
flash->mtd.writesize = 1;
flash->mtd.size = flash->caps->size;
flash->mtd._read = mchp23k256_read;
flash->mtd._write = mchp23k256_write;
err = mtd_device_register(&flash->mtd, data ? data->parts : NULL,
data ? data->nr_parts : 0);
if (err)
return err;
return 0;
}
static int mchp23k256_remove(struct spi_device *spi)
{
struct mchp23k256_flash *flash = spi_get_drvdata(spi);
return mtd_device_unregister(&flash->mtd);
}
static const struct of_device_id mchp23k256_of_table[] = {
{
.compatible = "microchip,mchp23k256",
.data = &mchp23k256_caps,
},
{
.compatible = "microchip,mchp23lcv1024",
.data = &mchp23lcv1024_caps,
},
{}
};
MODULE_DEVICE_TABLE(of, mchp23k256_of_table);
static struct spi_driver mchp23k256_driver = {
.driver = {
.name = "mchp23k256",
.of_match_table = of_match_ptr(mchp23k256_of_table),
},
.probe = mchp23k256_probe,
.remove = mchp23k256_remove,
};
module_spi_driver(mchp23k256_driver);
MODULE_DESCRIPTION("MTD SPI driver for MCHP23K256 RAM chips");
MODULE_AUTHOR("Andrew Lunn <andre@lunn.ch>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("spi:mchp23k256");