[linux-2.6-block.git] / drivers / mtd / devices / powernv_flash.c

/*
 * 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.
 */

#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;
}

/**
 * @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);
}

/**
 * @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);
}

/**
 * @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;

	erase->state = MTD_ERASING;

	/* 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);

	if (rc) {
		erase->fail_addr = erase->addr;
		erase->state = MTD_ERASE_FAILED;
	} else {
		erase->state = MTD_ERASE_DONE;
	}
	mtd_erase_callback(erase);
	return rc;
}

/**
 * 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;

	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 = 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;
}

/**
 * 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 int powernv_flash_release(struct platform_device *pdev)
{
	struct powernv_flash *data = dev_get_drvdata(&(pdev->dev));

	/* All resources should be freed automatically */
	return 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		= 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 <cyril.bur@au1.ibm.com>");
MODULE_DESCRIPTION("MTD abstraction for OPAL flash");
Commit	Line	Data
1cbb4a1c CB	1	/*
	2	* OPAL PNOR flash MTD abstraction
	3	*
	4	* Copyright IBM 2015
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*/
	16
	17	#include <linux/kernel.h>
	18	#include <linux/module.h>
	19	#include <linux/errno.h>
	20	#include <linux/of.h>
	21	#include <linux/of_address.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/string.h>
	24	#include <linux/slab.h>
	25	#include <linux/mtd/mtd.h>
	26	#include <linux/mtd/partitions.h>
	27
	28	#include <linux/debugfs.h>
	29	#include <linux/seq_file.h>
	30
	31	#include <asm/opal.h>
	32
	33
	34	/*
	35	* This driver creates the a Linux MTD abstraction for platform PNOR flash
	36	* backed by OPAL calls
	37	*/
	38
	39	struct powernv_flash {
	40	struct mtd_info mtd;
	41	u32 id;
	42	};
	43
	44	enum flash_op {
	45	FLASH_OP_READ,
	46	FLASH_OP_WRITE,
	47	FLASH_OP_ERASE,
	48	};
	49
efe69414 CB	50	/*
	51	* Don't return -ERESTARTSYS if we can't get a token, the MTD core
	52	* might have split up the call from userspace and called into the
	53	* driver more than once, we'll already have done some amount of work.
	54	*/
1cbb4a1c CB	55	static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op,
	56	loff_t offset, size_t len, size_t retlen, u_char buf)
	57	{
	58	struct powernv_flash info = (struct powernv_flash )mtd->priv;
	59	struct device *dev = &mtd->dev;
	60	int token;
	61	struct opal_msg msg;
	62	int rc;
	63
	64	dev_dbg(dev, "%s(op=%d, offset=0x%llx, len=%zu)\n",
	65	__func__, op, offset, len);
	66
	67	token = opal_async_get_token_interruptible();
	68	if (token < 0) {
	69	if (token != -ERESTARTSYS)
	70	dev_err(dev, "Failed to get an async token\n");
efe69414 CB	71	else
efe69414 CB	72	token = -EINTR;
1cbb4a1c CB	73	return token;
	74	}
	75
	76	switch (op) {
	77	case FLASH_OP_READ:
	78	rc = opal_flash_read(info->id, offset, __pa(buf), len, token);
	79	break;
	80	case FLASH_OP_WRITE:
	81	rc = opal_flash_write(info->id, offset, __pa(buf), len, token);
	82	break;
	83	case FLASH_OP_ERASE:
	84	rc = opal_flash_erase(info->id, offset, len, token);
	85	break;
	86	default:
44e2aa2b CB	87	WARN_ON_ONCE(1);
	88	opal_async_release_token(token);
	89	return -EIO;
1cbb4a1c CB	90	}
1cbb4a1c CB	91
6f469b67 CB	92	if (rc == OPAL_ASYNC_COMPLETION) {
	93	rc = opal_async_wait_response_interruptible(token, &msg);
	94	if (rc) {
	95	/*
	96	* If we return the mtd core will free the
	97	* buffer we've just passed to OPAL but OPAL
	98	* will continue to read or write from that
	99	* memory.
	100	* It may be tempting to ultimately return 0
	101	* if we're doing a read or a write since we
	102	* are going to end up waiting until OPAL is
	103	* done. However, because the MTD core sends
	104	* us the userspace request in chunks, we need
	105	* it to know we've been interrupted.
	106	*/
	107	rc = -EINTR;
	108	if (opal_async_wait_response(token, &msg))
	109	dev_err(dev, "opal_async_wait_response() failed\n");
	110	goto out;
	111	}
	112	rc = opal_get_async_rc(msg);
	113	}
25ee52e6	114
6f469b67 CB	115	/*
	116	* OPAL does mutual exclusion on the flash, it will return
	117	* OPAL_BUSY.
	118	* During firmware updates by the service processor OPAL may
	119	* be (temporarily) prevented from accessing the flash, in
	120	* this case OPAL will also return OPAL_BUSY.
	121	* Both cases aren't errors exactly but the flash could have
	122	* changed, userspace should be informed.
	123	*/
	124	if (rc != OPAL_SUCCESS && rc != OPAL_BUSY)
1cbb4a1c CB	125	dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",
1cbb4a1c CB	126	op, rc);
1cbb4a1c	127
6f469b67 CB	128	if (rc == OPAL_SUCCESS && retlen)
6f469b67 CB	129	*retlen = len;
1cbb4a1c	130
6f469b67	131	rc = opal_error_code(rc);
25ee52e6 CB	132	out:
25ee52e6 CB	133	opal_async_release_token(token);
1cbb4a1c CB	134	return rc;
	135	}
	136
	137	/**
	138	* @mtd: the device
	139	* @from: the offset to read from
	140	* @len: the number of bytes to read
	141	* @retlen: the number of bytes actually read
	142	* @buf: the filled in buffer
	143	*
	144	* Returns 0 if read successful, or -ERRNO if an error occurred
	145	*/
	146	static int powernv_flash_read(struct mtd_info *mtd, loff_t from, size_t len,
	147	size_t retlen, u_char buf)
	148	{
	149	return powernv_flash_async_op(mtd, FLASH_OP_READ, from,
	150	len, retlen, buf);
	151	}
	152
	153	/**
	154	* @mtd: the device
	155	* @to: the offset to write to
	156	* @len: the number of bytes to write
	157	* @retlen: the number of bytes actually written
	158	* @buf: the buffer to get bytes from
	159	*
	160	* Returns 0 if write successful, -ERRNO if error occurred
	161	*/
	162	static int powernv_flash_write(struct mtd_info *mtd, loff_t to, size_t len,
	163	size_t retlen, const u_char buf)
	164	{
	165	return powernv_flash_async_op(mtd, FLASH_OP_WRITE, to,
	166	len, retlen, (u_char *)buf);
	167	}
	168
	169	/**
	170	* @mtd: the device
	171	* @erase: the erase info
	172	* Returns 0 if erase successful or -ERRNO if an error occurred
	173	*/
	174	static int powernv_flash_erase(struct mtd_info mtd, struct erase_info erase)
	175	{
	176	int rc;
	177
	178	erase->state = MTD_ERASING;
	179
	180	/* todo: register our own notifier to do a true async implementation */
	181	rc = powernv_flash_async_op(mtd, FLASH_OP_ERASE, erase->addr,
	182	erase->len, NULL, NULL);
	183
	184	if (rc) {
	185	erase->fail_addr = erase->addr;
	186	erase->state = MTD_ERASE_FAILED;
	187	} else {
	188	erase->state = MTD_ERASE_DONE;
	189	}
	190	mtd_erase_callback(erase);
	191	return rc;
	192	}
	193
	194	/**
	195	* powernv_flash_set_driver_info - Fill the mtd_info structure and docg3
	196	* structure @pdev: The platform device
	197	* @mtd: The structure to fill
198	*/
199	static int powernv_flash_set_driver_info(struct device *dev,
200	struct mtd_info *mtd)
201	{
202	u64 size;
203	u32 erase_size;
204	int rc;
205
206	rc = of_property_read_u32(dev->of_node, "ibm,flash-block-size",
207	&erase_size);
208	if (rc) {
209	dev_err(dev, "couldn't get resource block size information\n");
210	return rc;
211	}
212
213	rc = of_property_read_u64(dev->of_node, "reg", &size);
214	if (rc) {
215	dev_err(dev, "couldn't get resource size information\n");
216	return rc;
217	}
218
219	/*
220	* Going to have to check what details I need to set and how to
221	* get them
222	*/
223	mtd->name = of_get_property(dev->of_node, "name", NULL);
224	mtd->type = MTD_NORFLASH;
225	mtd->flags = MTD_WRITEABLE;
226	mtd->size = size;
227	mtd->erasesize = erase_size;
228	mtd->writebufsize = mtd->writesize = 1;
229	mtd->owner = THIS_MODULE;
230	mtd->_erase = powernv_flash_erase;
231	mtd->_read = powernv_flash_read;
232	mtd->_write = powernv_flash_write;
233	mtd->dev.parent = dev;
234	return 0;
235	}
236
237	/**
238	* powernv_flash_probe
239	* @pdev: platform device
240	*
241	* Returns 0 on success, -ENOMEM, -ENXIO on error
242	*/
243	static int powernv_flash_probe(struct platform_device *pdev)
244	{
245	struct device *dev = &pdev->dev;
246	struct powernv_flash *data;
247	int ret;
248
249	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
e32ec15a CB	250	if (!data)
	251	return -ENOMEM;
	252
1cbb4a1c CB	253	data->mtd.priv = data;
	254
	255	ret = of_property_read_u32(dev->of_node, "ibm,opal-id", &(data->id));
	256	if (ret) {
	257	dev_err(dev, "no device property 'ibm,opal-id'\n");
e32ec15a	258	return ret;
1cbb4a1c CB	259	}
	260
	261	ret = powernv_flash_set_driver_info(dev, &data->mtd);
	262	if (ret)
e32ec15a	263	return ret;
1cbb4a1c CB	264
	265	dev_set_drvdata(dev, data);
	266
	267	/*
	268	* The current flash that skiboot exposes is one contiguous flash chip
	269	* with an ffs partition at the start, it should prove easier for users
	270	* to deal with partitions or not as they see fit
	271	*/
e32ec15a	272	return mtd_device_register(&data->mtd, NULL, 0);
1cbb4a1c CB	273	}
	274
	275	/**
	276	* op_release - Release the driver
	277	* @pdev: the platform device
	278	*
	279	* Returns 0
	280	*/
	281	static int powernv_flash_release(struct platform_device *pdev)
	282	{
	283	struct powernv_flash *data = dev_get_drvdata(&(pdev->dev));
	284
	285	/* All resources should be freed automatically */
	286	return mtd_device_unregister(&(data->mtd));
	287	}
	288
	289	static const struct of_device_id powernv_flash_match[] = {
	290	{ .compatible = "ibm,opal-flash" },
	291	{}
	292	};
	293
	294	static struct platform_driver powernv_flash_driver = {
	295	.driver = {
	296	.name = "powernv_flash",
	297	.of_match_table = powernv_flash_match,
	298	},
	299	.remove = powernv_flash_release,
	300	.probe = powernv_flash_probe,
	301	};
	302
	303	module_platform_driver(powernv_flash_driver);
	304
	305	MODULE_DEVICE_TABLE(of, powernv_flash_match);
	306	MODULE_LICENSE("GPL");
	307	MODULE_AUTHOR("Cyril Bur <cyril.bur@au1.ibm.com>");
	308	MODULE_DESCRIPTION("MTD abstraction for OPAL flash");