diff options
Diffstat (limited to 'drivers/mtd/devices/powernv_flash.c')
| -rw-r--r-- | drivers/mtd/devices/powernv_flash.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/drivers/mtd/devices/powernv_flash.c b/drivers/mtd/devices/powernv_flash.c new file mode 100644 index 0000000..d5b870b --- /dev/null +++ b/drivers/mtd/devices/powernv_flash.c @@ -0,0 +1,285 @@ +/* + * 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, +}; + +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"); |
