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path: root/drivers/mtd/devices/powernv_flash.c
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Diffstat (limited to 'drivers/mtd/devices/powernv_flash.c')
-rw-r--r--drivers/mtd/devices/powernv_flash.c297
1 files changed, 297 insertions, 0 deletions
diff --git a/drivers/mtd/devices/powernv_flash.c b/drivers/mtd/devices/powernv_flash.c
new file mode 100644
index 0000000000..36e060386e
--- /dev/null
+++ b/drivers/mtd/devices/powernv_flash.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * OPAL PNOR flash MTD abstraction
+ *
+ * Copyright IBM 2015
+ */
+
+#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,
+};
+
+/*
+ * Don't return -ERESTARTSYS if we can't get a token, the MTD core
+ * might have split up the call from userspace and called into the
+ * driver more than once, we'll already have done some amount of work.
+ */
+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");
+ else
+ token = -EINTR;
+ 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:
+ WARN_ON_ONCE(1);
+ opal_async_release_token(token);
+ return -EIO;
+ }
+
+ if (rc == OPAL_ASYNC_COMPLETION) {
+ rc = opal_async_wait_response_interruptible(token, &msg);
+ if (rc) {
+ /*
+ * If we return the mtd core will free the
+ * buffer we've just passed to OPAL but OPAL
+ * will continue to read or write from that
+ * memory.
+ * It may be tempting to ultimately return 0
+ * if we're doing a read or a write since we
+ * are going to end up waiting until OPAL is
+ * done. However, because the MTD core sends
+ * us the userspace request in chunks, we need
+ * it to know we've been interrupted.
+ */
+ rc = -EINTR;
+ if (opal_async_wait_response(token, &msg))
+ dev_err(dev, "opal_async_wait_response() failed\n");
+ goto out;
+ }
+ rc = opal_get_async_rc(msg);
+ }
+
+ /*
+ * OPAL does mutual exclusion on the flash, it will return
+ * OPAL_BUSY.
+ * During firmware updates by the service processor OPAL may
+ * be (temporarily) prevented from accessing the flash, in
+ * this case OPAL will also return OPAL_BUSY.
+ * Both cases aren't errors exactly but the flash could have
+ * changed, userspace should be informed.
+ */
+ if (rc != OPAL_SUCCESS && rc != OPAL_BUSY)
+ dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",
+ op, rc);
+
+ if (rc == OPAL_SUCCESS && retlen)
+ *retlen = len;
+
+ rc = opal_error_code(rc);
+out:
+ opal_async_release_token(token);
+ return rc;
+}
+
+/**
+ * powernv_flash_read
+ * @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);
+}
+
+/**
+ * powernv_flash_write
+ * @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);
+}
+
+/**
+ * powernv_flash_erase
+ * @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;
+
+ rc = powernv_flash_async_op(mtd, FLASH_OP_ERASE, erase->addr,
+ erase->len, NULL, NULL);
+ if (rc)
+ erase->fail_addr = erase->addr;
+
+ return rc;
+}
+
+/**
+ * powernv_flash_set_driver_info - Fill the mtd_info structure and docg3
+ * @dev: The device structure
+ * @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 = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
+ 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;
+ mtd_set_of_node(mtd, dev->of_node);
+ 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)
+ return -ENOMEM;
+
+ 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");
+ return ret;
+ }
+
+ ret = powernv_flash_set_driver_info(dev, &data->mtd);
+ if (ret)
+ return ret;
+
+ 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
+ */
+ return mtd_device_register(&data->mtd, NULL, 0);
+}
+
+/**
+ * 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 */
+ WARN_ON(mtd_device_unregister(&data->mtd));
+
+ return 0;
+}
+
+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");