[PATCH V3] drivers/mtd: add powernv flash MTD abstraction driver
Cyril Bur
cyrilbur at gmail.com
Fri Jun 5 14:40:01 AEST 2015
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 at gmail.com>
> Signed-off-by: Joel Stanley <joel at jms.id.au>
> Signed-off-by: Jeremy Kerr <jk at 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 at au1.ibm.com>");
> +MODULE_DESCRIPTION("MTD abstraction for OPAL flash");
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