// SPDX-License-Identifier: GPL-2.0-or-later
/*
* OPAL PNOR flash MTD abstraction
*
* Copyright IBM 2015
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <asm/opal.h>
/*
* This driver creates the a Linux MTD abstraction for platform PNOR flash
* backed by OPAL calls
*/
struct powernv_flash {
struct mtd_info mtd;
u32 id;
};
enum flash_op {
FLASH_OP_READ,
FLASH_OP_WRITE,
FLASH_OP_ERASE,
};
/*
* Don't return -ERESTARTSYS if we can't get a token, the MTD core
* might have split up the call from userspace and called into the
* driver more than once, we'll already have done some amount of work.
*/
static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op,
loff_t offset, size_t len, size_t *retlen, u_char *buf)
{
struct powernv_flash *info = (struct powernv_flash *)mtd->priv;
struct device *dev = &mtd->dev;
int token;
struct opal_msg msg;
int rc;
dev_dbg(dev, "%s(op=%d, offset=0x%llx, len=%zu)\n",
__func__, op, offset, len);
token = opal_async_get_token_interruptible();
if (token < 0) {
if (token != -ERESTARTSYS)
dev_err(dev, "Failed to get an async token\n");
else
token = -EINTR;
return token;
}
switch (op) {
case FLASH_OP_READ:
rc = opal_flash_read(info->id, offset, __pa(buf), len, token);
break;
case FLASH_OP_WRITE:
rc = opal_flash_write(info->id, offset, __pa(buf), len, token);
break;
case FLASH_OP_ERASE:
rc = opal_flash_erase(info->id, offset, len, token);
break;
default:
WARN_ON_ONCE(1);
opal_async_release_token(token);
return -EIO;
}
if (rc == OPAL_ASYNC_COMPLETION) {
rc = opal_async_wait_response_interruptible(token, &msg);
if (rc) {
/*
* If we return the mtd core will free the
* buffer we've just passed to OPAL but OPAL
* will continue to read or write from that
* memory.
* It may be tempting to ultimately return 0
* if we're doing a read or a write since we
* are going to end up waiting until OPAL is
* done. However, because the MTD core sends
* us the userspace request in chunks, we need
* it to know we've been interrupted.
*/
rc = -EINTR;
if (opal_async_wait_response(token, &msg))
dev_err(dev, "opal_async_wait_response() failed\n");
goto out;
}
rc = opal_get_async_rc(msg);
}
/*
* OPAL does mutual exclusion on the flash, it will return
* OPAL_BUSY.
* During firmware updates by the service processor OPAL may
* be (temporarily) prevented from accessing the flash, in
* this case OPAL will also return OPAL_BUSY.
* Both cases aren't errors exactly but the flash could have
* changed, userspace should be informed.
*/
if (rc != OPAL_SUCCESS && rc != OPAL_BUSY)
dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",
op, rc);
if (rc == OPAL_SUCCESS && retlen)
*retlen = len;
rc = opal_error_code(rc);
out:
opal_async_release_token(token);
return rc;
}
/**
* powernv_flash_read
* @mtd: the device
* @from: the offset to read from
* @len: the number of bytes to read
* @retlen: the number of bytes actually read
* @buf: the filled in buffer
*
* Returns 0 if read successful, or -ERRNO if an error occurred
*/
static int powernv_flash_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
return powernv_flash_async_op(mtd, FLASH_OP_READ, from,
len, retlen, buf);
}
/**
* powernv_flash_write
* @mtd: the device
* @to: the offset to write to
* @len: the number of bytes to write
* @retlen: the number of bytes actually written
* @buf: the buffer to get bytes from
*
* Returns 0 if write successful, -ERRNO if error occurred
*/
static int powernv_flash_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
return powernv_flash_async_op(mtd, FLASH_OP_WRITE, to,
len, retlen, (u_char *)buf);
}
/**
* powernv_flash_erase
* @mtd: the device
* @erase: the erase info
* Returns 0 if erase successful or -ERRNO if an error occurred
*/
static int powernv_flash_erase(struct mtd_info *mtd, struct erase_info *erase)
{
int rc;
rc = powernv_flash_async_op(mtd, FLASH_OP_ERASE, erase->addr,
erase->len, NULL, NULL);
if (rc)
erase->fail_addr = erase->addr;
return rc;
}
/**
* powernv_flash_set_driver_info - Fill the mtd_info structure and docg3
* @dev: The device structure
* @mtd: The structure to fill
*/
static int powernv_flash_set_driver_info(struct device *dev,
struct mtd_info *mtd)
{
u64 size;
u32 erase_size;
int rc;
rc = of_property_read_u32(dev->of_node, "ibm,flash-block-size",
&erase_size);
if (rc) {
dev_err(dev, "couldn't get resource block size information\n");
return rc;
}
rc = of_property_read_u64(dev->of_node, "reg", &size);
if (rc) {
dev_err(dev, "couldn't get resource size information\n");
return rc;
}
/*
* Going to have to check what details I need to set and how to
* get them
*/
mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
if (!mtd->name)
return -ENOMEM;
mtd->type = MTD_NORFLASH;
mtd->flags = MTD_WRITEABLE;
mtd->size = size;
mtd->erasesize = erase_size;
mtd->writebufsize = mtd->writesize = 1;
mtd->owner = THIS_MODULE;
mtd->_erase = powernv_flash_erase;
mtd->_read = powernv_flash_read;
mtd->_write = powernv_flash_write;
mtd->dev.parent = dev;
mtd_set_of_node(mtd, dev->of_node);
return 0;
}
/**
* powernv_flash_probe
* @pdev: platform device
*
* Returns 0 on success, -ENOMEM, -ENXIO on error
*/
static int powernv_flash_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct powernv_flash *data;
int ret;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->mtd.priv = data;
ret = of_property_read_u32(dev->of_node, "ibm,opal-id", &(data->id));
if (ret) {
dev_err(dev, "no device property 'ibm,opal-id'\n");
return ret;
}
ret = powernv_flash_set_driver_info(dev, &data->mtd);
if (ret)
return ret;
dev_set_drvdata(dev, data);
/*
* The current flash that skiboot exposes is one contiguous flash chip
* with an ffs partition at the start, it should prove easier for users
* to deal with partitions or not as they see fit
*/
return mtd_device_register(&data->mtd, NULL, 0);
}
/**
* op_release - Release the driver
* @pdev: the platform device
*
* Returns 0
*/
static void powernv_flash_release(struct platform_device *pdev)
{
struct powernv_flash *data = dev_get_drvdata(&(pdev->dev));
/* All resources should be freed automatically */
WARN_ON(mtd_device_unregister(&data->mtd));
}
static const struct of_device_id powernv_flash_match[] = {
{ .compatible = "ibm,opal-flash" },
{}
};
static struct platform_driver powernv_flash_driver = {
.driver = {
.name = "powernv_flash",
.of_match_table = powernv_flash_match,
},
.remove_new = powernv_flash_release,
.probe = powernv_flash_probe,
};
module_platform_driver(powernv_flash_driver);
MODULE_DEVICE_TABLE(of, powernv_flash_match);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Cyril Bur <[email protected]>");
MODULE_DESCRIPTION("MTD abstraction for OPAL flash");
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