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295 lines
7.2 KiB
295 lines
7.2 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* OPAL PNOR flash MTD abstraction |
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* |
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* Copyright IBM 2015 |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/errno.h> |
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#include <linux/of.h> |
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#include <linux/of_address.h> |
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#include <linux/platform_device.h> |
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#include <linux/string.h> |
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#include <linux/slab.h> |
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#include <linux/mtd/mtd.h> |
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#include <linux/mtd/partitions.h> |
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#include <linux/debugfs.h> |
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#include <linux/seq_file.h> |
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#include <asm/opal.h> |
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/* |
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* This driver creates the a Linux MTD abstraction for platform PNOR flash |
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* backed by OPAL calls |
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*/ |
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struct powernv_flash { |
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struct mtd_info mtd; |
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u32 id; |
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}; |
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enum flash_op { |
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FLASH_OP_READ, |
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FLASH_OP_WRITE, |
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FLASH_OP_ERASE, |
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}; |
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/* |
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* Don't return -ERESTARTSYS if we can't get a token, the MTD core |
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* might have split up the call from userspace and called into the |
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* driver more than once, we'll already have done some amount of work. |
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*/ |
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static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op, |
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loff_t offset, size_t len, size_t *retlen, u_char *buf) |
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{ |
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struct powernv_flash *info = (struct powernv_flash *)mtd->priv; |
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struct device *dev = &mtd->dev; |
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int token; |
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struct opal_msg msg; |
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int rc; |
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dev_dbg(dev, "%s(op=%d, offset=0x%llx, len=%zu)\n", |
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__func__, op, offset, len); |
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token = opal_async_get_token_interruptible(); |
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if (token < 0) { |
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if (token != -ERESTARTSYS) |
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dev_err(dev, "Failed to get an async token\n"); |
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else |
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token = -EINTR; |
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return token; |
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} |
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switch (op) { |
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case FLASH_OP_READ: |
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rc = opal_flash_read(info->id, offset, __pa(buf), len, token); |
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break; |
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case FLASH_OP_WRITE: |
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rc = opal_flash_write(info->id, offset, __pa(buf), len, token); |
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break; |
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case FLASH_OP_ERASE: |
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rc = opal_flash_erase(info->id, offset, len, token); |
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break; |
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default: |
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WARN_ON_ONCE(1); |
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opal_async_release_token(token); |
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return -EIO; |
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} |
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if (rc == OPAL_ASYNC_COMPLETION) { |
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rc = opal_async_wait_response_interruptible(token, &msg); |
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if (rc) { |
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/* |
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* If we return the mtd core will free the |
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* buffer we've just passed to OPAL but OPAL |
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* will continue to read or write from that |
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* memory. |
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* It may be tempting to ultimately return 0 |
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* if we're doing a read or a write since we |
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* are going to end up waiting until OPAL is |
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* done. However, because the MTD core sends |
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* us the userspace request in chunks, we need |
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* it to know we've been interrupted. |
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*/ |
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rc = -EINTR; |
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if (opal_async_wait_response(token, &msg)) |
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dev_err(dev, "opal_async_wait_response() failed\n"); |
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goto out; |
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} |
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rc = opal_get_async_rc(msg); |
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} |
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/* |
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* OPAL does mutual exclusion on the flash, it will return |
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* OPAL_BUSY. |
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* During firmware updates by the service processor OPAL may |
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* be (temporarily) prevented from accessing the flash, in |
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* this case OPAL will also return OPAL_BUSY. |
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* Both cases aren't errors exactly but the flash could have |
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* changed, userspace should be informed. |
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*/ |
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if (rc != OPAL_SUCCESS && rc != OPAL_BUSY) |
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dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n", |
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op, rc); |
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if (rc == OPAL_SUCCESS && retlen) |
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*retlen = len; |
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rc = opal_error_code(rc); |
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out: |
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opal_async_release_token(token); |
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return rc; |
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} |
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/** |
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* powernv_flash_read |
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* @mtd: the device |
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* @from: the offset to read from |
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* @len: the number of bytes to read |
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* @retlen: the number of bytes actually read |
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* @buf: the filled in buffer |
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* |
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* Returns 0 if read successful, or -ERRNO if an error occurred |
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*/ |
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static int powernv_flash_read(struct mtd_info *mtd, loff_t from, size_t len, |
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size_t *retlen, u_char *buf) |
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{ |
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return powernv_flash_async_op(mtd, FLASH_OP_READ, from, |
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len, retlen, buf); |
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} |
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/** |
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* powernv_flash_write |
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* @mtd: the device |
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* @to: the offset to write to |
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* @len: the number of bytes to write |
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* @retlen: the number of bytes actually written |
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* @buf: the buffer to get bytes from |
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* |
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* Returns 0 if write successful, -ERRNO if error occurred |
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*/ |
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static int powernv_flash_write(struct mtd_info *mtd, loff_t to, size_t len, |
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size_t *retlen, const u_char *buf) |
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{ |
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return powernv_flash_async_op(mtd, FLASH_OP_WRITE, to, |
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len, retlen, (u_char *)buf); |
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} |
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/** |
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* powernv_flash_erase |
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* @mtd: the device |
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* @erase: the erase info |
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* Returns 0 if erase successful or -ERRNO if an error occurred |
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*/ |
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static int powernv_flash_erase(struct mtd_info *mtd, struct erase_info *erase) |
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{ |
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int rc; |
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rc = powernv_flash_async_op(mtd, FLASH_OP_ERASE, erase->addr, |
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erase->len, NULL, NULL); |
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if (rc) |
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erase->fail_addr = erase->addr; |
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return rc; |
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} |
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/** |
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* powernv_flash_set_driver_info - Fill the mtd_info structure and docg3 |
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* @dev: The device structure |
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* @mtd: The structure to fill |
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*/ |
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static int powernv_flash_set_driver_info(struct device *dev, |
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struct mtd_info *mtd) |
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{ |
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u64 size; |
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u32 erase_size; |
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int rc; |
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rc = of_property_read_u32(dev->of_node, "ibm,flash-block-size", |
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&erase_size); |
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if (rc) { |
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dev_err(dev, "couldn't get resource block size information\n"); |
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return rc; |
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} |
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rc = of_property_read_u64(dev->of_node, "reg", &size); |
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if (rc) { |
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dev_err(dev, "couldn't get resource size information\n"); |
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return rc; |
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} |
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/* |
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* Going to have to check what details I need to set and how to |
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* get them |
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*/ |
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mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node); |
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mtd->type = MTD_NORFLASH; |
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mtd->flags = MTD_WRITEABLE; |
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mtd->size = size; |
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mtd->erasesize = erase_size; |
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mtd->writebufsize = mtd->writesize = 1; |
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mtd->owner = THIS_MODULE; |
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mtd->_erase = powernv_flash_erase; |
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mtd->_read = powernv_flash_read; |
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mtd->_write = powernv_flash_write; |
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mtd->dev.parent = dev; |
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mtd_set_of_node(mtd, dev->of_node); |
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return 0; |
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} |
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/** |
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* powernv_flash_probe |
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* @pdev: platform device |
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* |
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* Returns 0 on success, -ENOMEM, -ENXIO on error |
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*/ |
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static int powernv_flash_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct powernv_flash *data; |
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int ret; |
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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data->mtd.priv = data; |
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ret = of_property_read_u32(dev->of_node, "ibm,opal-id", &(data->id)); |
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if (ret) { |
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dev_err(dev, "no device property 'ibm,opal-id'\n"); |
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return ret; |
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} |
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ret = powernv_flash_set_driver_info(dev, &data->mtd); |
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if (ret) |
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return ret; |
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dev_set_drvdata(dev, data); |
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/* |
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* The current flash that skiboot exposes is one contiguous flash chip |
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* with an ffs partition at the start, it should prove easier for users |
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* to deal with partitions or not as they see fit |
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*/ |
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return mtd_device_register(&data->mtd, NULL, 0); |
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} |
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/** |
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* op_release - Release the driver |
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* @pdev: the platform device |
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* |
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* Returns 0 |
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*/ |
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static int powernv_flash_release(struct platform_device *pdev) |
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{ |
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struct powernv_flash *data = dev_get_drvdata(&(pdev->dev)); |
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/* All resources should be freed automatically */ |
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return mtd_device_unregister(&(data->mtd)); |
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} |
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static const struct of_device_id powernv_flash_match[] = { |
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{ .compatible = "ibm,opal-flash" }, |
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{} |
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}; |
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static struct platform_driver powernv_flash_driver = { |
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.driver = { |
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.name = "powernv_flash", |
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.of_match_table = powernv_flash_match, |
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}, |
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.remove = powernv_flash_release, |
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.probe = powernv_flash_probe, |
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}; |
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module_platform_driver(powernv_flash_driver); |
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MODULE_DEVICE_TABLE(of, powernv_flash_match); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Cyril Bur <[email protected]>"); |
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MODULE_DESCRIPTION("MTD abstraction for OPAL flash");
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