[V3] drivers/mtd: 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 <cyrilbur@gmail.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
---
Hello Brian and MTD folk,
Could I please get an ACK for Michael to take this through the powerpc
tree.
Thanks.


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

On 06/02/2015 09:56 AM, 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>

Reviewed-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>

Neelesh.

> ---
> Hello Brian and MTD folk,
> Could I please get an ACK for Michael to take this through the powerpc
> tree.
> Thanks.
>
>
> 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
>
>

On Tue, 2015-06-02 at 14:26 +1000, 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>
> ---
> Hello Brian and MTD folk,
> Could I please get an ACK for Michael to take this through the powerpc
> tree.
> Thanks.
> 

Hello Brian,

As we have some deadlines approaching, I am getting pressure to ensure
this gets merged upstream as quickly as possible, please let me know if
there is anything more which can be done.

Thanks very much,

Cyril
> 
> 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");

On Fri, Jun 5, 2015 at 6:40 AM, Cyril Bur <cyrilbur@gmail.com> wrote:
> On Tue, 2015-06-02 at 14:26 +1000, 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>
>> ---
>> Hello Brian and MTD folk,
>> Could I please get an ACK for Michael to take this through the powerpc
>> tree.
>> Thanks.
>>
>
> Hello Brian,
>
> As we have some deadlines approaching, I am getting pressure to ensure
> this gets merged upstream as quickly as possible, please let me know if
> there is anything more which can be done.

FYI, Brian is not available for the next 1.5 weeks.
So I fear this driver has to wait for the next merge window.

On Fri, 2015-06-05 at 10:16 +0200, Richard Weinberger wrote:
> On Fri, Jun 5, 2015 at 6:40 AM, Cyril Bur <cyrilbur@gmail.com> wrote:
> > On Tue, 2015-06-02 at 14:26 +1000, 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>
> >> ---
> >> Hello Brian and MTD folk,
> >> Could I please get an ACK for Michael to take this through the powerpc
> >
> > As we have some deadlines approaching, I am getting pressure to ensure
> > this gets merged upstream as quickly as possible, please let me know if
> > there is anything more which can be done.
>
> FYI, Brian is not available for the next 1.5 weeks.
> So I fear this driver has to wait for the next merge window.

OK. We'll merge it via the powerpc tree and if there are any problems with it
we can fix them later.

cheers

Am 11.06.2015 um 07:43 schrieb Michael Ellerman:
> On Fri, 2015-06-05 at 10:16 +0200, Richard Weinberger wrote:
>> On Fri, Jun 5, 2015 at 6:40 AM, Cyril Bur <cyrilbur@gmail.com> wrote:
>>> On Tue, 2015-06-02 at 14:26 +1000, 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>
>>>> ---
>>>> Hello Brian and MTD folk,
>>>> Could I please get an ACK for Michael to take this through the powerpc
>>>
>>> As we have some deadlines approaching, I am getting pressure to ensure
>>> this gets merged upstream as quickly as possible, please let me know if
>>> there is anything more which can be done.
>>
>> FYI, Brian is not available for the next 1.5 weeks.
>> So I fear this driver has to wait for the next merge window.
> 
> OK. We'll merge it via the powerpc tree and if there are any problems with it
> we can fix them later.

..or be respectful, have patience and wait for Brian.

Thanks,
//richard