298 lines
7.2 KiB
C
298 lines
7.2 KiB
C
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// 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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WARN_ON(mtd_device_unregister(&data->mtd));
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return 0;
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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 <cyril.bur@au1.ibm.com>");
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MODULE_DESCRIPTION("MTD abstraction for OPAL flash");
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