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mtd: powernv: Add powernv flash MTD abstraction driver
Powerpc powernv platforms allow access to certain system flash devices through a firmwarwe interface. This change adds an mtd driver for these flash devices. Minor updates from Jeremy Kerr and Joel Stanley. Signed-off-by: Cyril Bur <[email protected]> Signed-off-by: Joel Stanley <[email protected]> Signed-off-by: Jeremy Kerr <[email protected]> Reviewed-by: Neelesh Gupta <[email protected]> Signed-off-by: Michael Ellerman <[email protected]>
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/* | ||
* OPAL PNOR flash MTD abstraction | ||
* | ||
* Copyright IBM 2015 | ||
* | ||
* This program is free software; you can redistribute it and/or modify | ||
* it under the terms of the GNU General Public License as published by | ||
* the Free Software Foundation; either version 2 of the License, or | ||
* (at your option) any later version. | ||
* | ||
* This program is distributed in the hope that it will be useful, | ||
* but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
* GNU General Public License for more details. | ||
*/ | ||
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#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> | ||
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#include <linux/debugfs.h> | ||
#include <linux/seq_file.h> | ||
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#include <asm/opal.h> | ||
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/* | ||
* This driver creates the a Linux MTD abstraction for platform PNOR flash | ||
* backed by OPAL calls | ||
*/ | ||
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struct powernv_flash { | ||
struct mtd_info mtd; | ||
u32 id; | ||
}; | ||
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enum flash_op { | ||
FLASH_OP_READ, | ||
FLASH_OP_WRITE, | ||
FLASH_OP_ERASE, | ||
}; | ||
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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; | ||
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dev_dbg(dev, "%s(op=%d, offset=0x%llx, len=%zu)\n", | ||
__func__, op, offset, len); | ||
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token = opal_async_get_token_interruptible(); | ||
if (token < 0) { | ||
if (token != -ERESTARTSYS) | ||
dev_err(dev, "Failed to get an async token\n"); | ||
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return token; | ||
} | ||
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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: | ||
BUG_ON(1); | ||
} | ||
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if (rc != OPAL_ASYNC_COMPLETION) { | ||
dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n", | ||
op, rc); | ||
opal_async_release_token(token); | ||
return -EIO; | ||
} | ||
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rc = opal_async_wait_response(token, &msg); | ||
opal_async_release_token(token); | ||
if (rc) { | ||
dev_err(dev, "opal async wait failed (rc %d)\n", rc); | ||
return -EIO; | ||
} | ||
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rc = be64_to_cpu(msg.params[1]); | ||
if (rc == OPAL_SUCCESS) { | ||
rc = 0; | ||
if (retlen) | ||
*retlen = len; | ||
} else { | ||
rc = -EIO; | ||
} | ||
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return rc; | ||
} | ||
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/** | ||
* @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); | ||
} | ||
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/** | ||
* @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); | ||
} | ||
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/** | ||
* @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; | ||
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erase->state = MTD_ERASING; | ||
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/* todo: register our own notifier to do a true async implementation */ | ||
rc = powernv_flash_async_op(mtd, FLASH_OP_ERASE, erase->addr, | ||
erase->len, NULL, NULL); | ||
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if (rc) { | ||
erase->fail_addr = erase->addr; | ||
erase->state = MTD_ERASE_FAILED; | ||
} else { | ||
erase->state = MTD_ERASE_DONE; | ||
} | ||
mtd_erase_callback(erase); | ||
return rc; | ||
} | ||
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/** | ||
* powernv_flash_set_driver_info - Fill the mtd_info structure and docg3 | ||
* structure @pdev: The platform device | ||
* @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; | ||
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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; | ||
} | ||
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rc = of_property_read_u64(dev->of_node, "reg", &size); | ||
if (rc) { | ||
dev_err(dev, "couldn't get resource size information\n"); | ||
return rc; | ||
} | ||
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/* | ||
* Going to have to check what details I need to set and how to | ||
* get them | ||
*/ | ||
mtd->name = of_get_property(dev->of_node, "name", NULL); | ||
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; | ||
return 0; | ||
} | ||
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/** | ||
* 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; | ||
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); | ||
if (!data) { | ||
ret = -ENOMEM; | ||
goto out; | ||
} | ||
data->mtd.priv = data; | ||
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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"); | ||
goto out; | ||
} | ||
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ret = powernv_flash_set_driver_info(dev, &data->mtd); | ||
if (ret) | ||
goto out; | ||
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dev_set_drvdata(dev, data); | ||
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/* | ||
* 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 | ||
*/ | ||
ret = mtd_device_register(&data->mtd, NULL, 0); | ||
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out: | ||
return ret; | ||
} | ||
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/** | ||
* op_release - Release the driver | ||
* @pdev: the platform device | ||
* | ||
* Returns 0 | ||
*/ | ||
static int powernv_flash_release(struct platform_device *pdev) | ||
{ | ||
struct powernv_flash *data = dev_get_drvdata(&(pdev->dev)); | ||
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/* All resources should be freed automatically */ | ||
return mtd_device_unregister(&(data->mtd)); | ||
} | ||
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static const struct of_device_id powernv_flash_match[] = { | ||
{ .compatible = "ibm,opal-flash" }, | ||
{} | ||
}; | ||
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static struct platform_driver powernv_flash_driver = { | ||
.driver = { | ||
.name = "powernv_flash", | ||
.of_match_table = powernv_flash_match, | ||
}, | ||
.remove = powernv_flash_release, | ||
.probe = powernv_flash_probe, | ||
}; | ||
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module_platform_driver(powernv_flash_driver); | ||
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MODULE_DEVICE_TABLE(of, powernv_flash_match); | ||
MODULE_LICENSE("GPL"); | ||
MODULE_AUTHOR("Cyril Bur <[email protected]>"); | ||
MODULE_DESCRIPTION("MTD abstraction for OPAL flash"); |