[PATCH V3] drivers/mtd: add powernv flash MTD abstraction driver

[PATCH V3] drivers/mtd: add powernv flash MTD abstraction driver

[Cyril Bur]

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 <cyrilbur@gmail.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
---
V2: Address Brian Norris' review
    Fix typos
    Change from NAND flash type to NOR flash type
    Correctness tweaks
V3: Address Neelesh Gupta's review
    Minor corrections
    Release the opal token on error
    Unregister mtd device on module remove
---
 drivers/mtd/devices/Kconfig         |   8 +
 drivers/mtd/devices/Makefile        |   1 +
 drivers/mtd/devices/powernv_flash.c | 286 ++++++++++++++++++++++++++++++++++++
 3 files changed, 295 insertions(+)
 create mode 100644 drivers/mtd/devices/powernv_flash.c

diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index c49d0b1..f73c416 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/drivers/mtd/devices/Kconfig
@@ -195,6 +195,14 @@ config MTD_BLOCK2MTD
 	  Testing MTD users (eg JFFS2) on large media and media that might
 	  be removed during a write (using the floppy drive).
 
+config MTD_POWERNV_FLASH
+	tristate "powernv flash MTD driver"
+	depends on PPC_POWERNV
+	help
+	  This provides an MTD device to access flash on powernv OPAL
+	  platforms from Linux. This device abstracts away the
+	  firmware interface for flash access.
+
 comment "Disk-On-Chip Device Drivers"
 
 config MTD_DOCG3
diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
index f0b0e61..7912d3a 100644
--- a/drivers/mtd/devices/Makefile
+++ b/drivers/mtd/devices/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_MTD_SPEAR_SMI)	+= spear_smi.o
 obj-$(CONFIG_MTD_SST25L)	+= sst25l.o
 obj-$(CONFIG_MTD_BCM47XXSFLASH)	+= bcm47xxsflash.o
 obj-$(CONFIG_MTD_ST_SPI_FSM)    += st_spi_fsm.o
+obj-$(CONFIG_MTD_POWERNV_FLASH)	+= powernv_flash.o
 
 
 CFLAGS_docg3.o			+= -I$(src)
diff --git a/drivers/mtd/devices/powernv_flash.c b/drivers/mtd/devices/powernv_flash.c
new file mode 100644
index 0000000..036d5b7
--- /dev/null
+++ b/drivers/mtd/devices/powernv_flash.c
@@ -0,0 +1,286 @@
+/*
+ * OPAL PNOR flash MTD abstraction
+ *
+ * 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,
+};
+
+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");
+
+		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:
+		BUG_ON(1);
+	}
+
+	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;
+	}
+
+	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;
+	}
+
+	rc = be64_to_cpu(msg.params[1]);
+	if (rc == OPAL_SUCCESS) {
+		rc = 0;
+		if (retlen)
+			*retlen = len;
+	} else {
+		rc = -EIO;
+	}
+
+	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 0;
+}
+
+/**
+ * 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) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	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");
+		goto out;
+	}
+
+	ret = powernv_flash_set_driver_info(dev, &data->mtd);
+	if (ret)
+		goto out;
+
+	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
+	 */
+	ret = mtd_device_register(&data->mtd, NULL, 0);
+
+out:
+	return ret;
+}
+
+/**
+ * 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");
-- 
1.9.1

Re: [PATCH V3] drivers/mtd: add powernv flash MTD abstraction driver

[Neelesh Gupta]

[-- Attachment #1: Type: text/plain, Size: 2597 bytes --]


[...]
> +/**
> + * @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 ? You also document the same  '.... or -ERRNO if an error 
occurred'

> +	return 0;
> +}
> +
> +/**
> + * 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) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +	data->mtd.priv = data;

'mtd' is contained within the 'data' so you can cast 'mtd' to get the 'data'
anywhere you want using container_of() macro.. 'priv' can be used to pass
an unrelated structure ....  just a thought, you may ignore it.. :)

Rest looks ok.

Neelesh.



[-- Attachment #2: Type: text/html, Size: 3205 bytes --]

Re: [PATCH V3] drivers/mtd: add powernv flash MTD abstraction driver

[Cyril Bur]

On Fri, 2015-05-29 at 14:52 +0530, Neelesh Gupta wrote:
> 
> [...]
> 
> > +/**
> > + * @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 ? You also document the same  '.... or -ERRNO if an error
> occurred'
> 
Good catch, I'll amend.

> > +	return 0;
> > +}
> > +
> > +/**
> > + * 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) {
> > +		ret = -ENOMEM;
> > +		goto out;
> > +	}
> > +	data->mtd.priv = data;
> 
> 'mtd' is contained within the 'data' so you can cast 'mtd' to get the
> 'data'
> anywhere you want using container_of() macro.. 'priv' can be used to
> pass
> an unrelated structure ....  just a thought, you may ignore it.. :)

Yeah, I think I couldn't agree with myself when I wrote and I figured
there might be something I'd want to use priv for. There never was, that
stayed. I realised it got quite circular and there are now many ways of
getting back to data, I can't see any harm in leaving it like that,
except the strangeness of it.

Thanks,

Cyril
> Rest looks ok.
> 
> Neelesh.
> 
> 

[PATCH V3] drivers/mtd: add powernv flash MTD abstraction driver

[Cyril Bur]

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 <cyrilbur@gmail.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
---
V2: Address Brian Norris' review
    Fix typos
    Change from NAND flash type to NOR flash type
    Correctness tweaks
V3: Address Neelesh Gupta's review
    Minor corrections
    Release the opal token on error
    Unregister mtd device on module remove
---
 drivers/mtd/devices/Kconfig         |   8 +
 drivers/mtd/devices/Makefile        |   1 +
 drivers/mtd/devices/powernv_flash.c | 286 ++++++++++++++++++++++++++++++++++++
 3 files changed, 295 insertions(+)
 create mode 100644 drivers/mtd/devices/powernv_flash.c

diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index c49d0b1..f73c416 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/drivers/mtd/devices/Kconfig
@@ -195,6 +195,14 @@ config MTD_BLOCK2MTD
 	  Testing MTD users (eg JFFS2) on large media and media that might
 	  be removed during a write (using the floppy drive).
 
+config MTD_POWERNV_FLASH
+	tristate "powernv flash MTD driver"
+	depends on PPC_POWERNV
+	help
+	  This provides an MTD device to access flash on powernv OPAL
+	  platforms from Linux. This device abstracts away the
+	  firmware interface for flash access.
+
 comment "Disk-On-Chip Device Drivers"
 
 config MTD_DOCG3
diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
index f0b0e61..7912d3a 100644
--- a/drivers/mtd/devices/Makefile
+++ b/drivers/mtd/devices/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_MTD_SPEAR_SMI)	+= spear_smi.o
 obj-$(CONFIG_MTD_SST25L)	+= sst25l.o
 obj-$(CONFIG_MTD_BCM47XXSFLASH)	+= bcm47xxsflash.o
 obj-$(CONFIG_MTD_ST_SPI_FSM)    += st_spi_fsm.o
+obj-$(CONFIG_MTD_POWERNV_FLASH)	+= powernv_flash.o
 
 
 CFLAGS_docg3.o			+= -I$(src)
diff --git a/drivers/mtd/devices/powernv_flash.c b/drivers/mtd/devices/powernv_flash.c
new file mode 100644
index 0000000..777e09f
--- /dev/null
+++ b/drivers/mtd/devices/powernv_flash.c
@@ -0,0 +1,286 @@
+/*
+ * OPAL PNOR flash MTD abstraction
+ *
+ * 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,
+};
+
+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");
+
+		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:
+		BUG_ON(1);
+	}
+
+	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;
+	}
+
+	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;
+	}
+
+	rc = be64_to_cpu(msg.params[1]);
+	if (rc == OPAL_SUCCESS) {
+		rc = 0;
+		if (retlen)
+			*retlen = len;
+	} else {
+		rc = -EIO;
+	}
+
+	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) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	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");
+		goto out;
+	}
+
+	ret = powernv_flash_set_driver_info(dev, &data->mtd);
+	if (ret)
+		goto out;
+
+	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
+	 */
+	ret = mtd_device_register(&data->mtd, NULL, 0);
+
+out:
+	return ret;
+}
+
+/**
+ * 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");
-- 
1.9.1

Re: [V3] drivers/mtd: add powernv flash MTD abstraction driver

[Michael Ellerman]

On Mon, 2015-01-06 at 03:26:44 UTC, Cyril Bur wrote:
> 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 <cyrilbur@gmail.com>
> Signed-off-by: Joel Stanley <joel@jms.id.au>
> Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
> ---
> V2: Address Brian Norris' review
>     Fix typos
>     Change from NAND flash type to NOR flash type
>     Correctness tweaks
> V3: Address Neelesh Gupta's review
>     Minor corrections
>     Release the opal token on error
>     Unregister mtd device on module remove


You seem to have dropped Brian and linux-mtd from Cc?

Please put them back and repost, with a request for an ACK so we can take it
via the powerpc tree.

cheers