mtd: add MEMWRITE ioctl

[Linux-MTD Mailing List]

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=e99d8b089a6c6fd72f022168e3bf8f22d4e5e137
Commit:     e99d8b089a6c6fd72f022168e3bf8f22d4e5e137
Parent:     beb133fc165e1289c858d8f952b982b7d0b313cd
Author:     Brian Norris <computersforpeace at gmail.com>
AuthorDate: Fri Sep 9 09:59:03 2011 -0700
Committer:  Artem Bityutskiy <artem.bityutskiy at intel.com>
CommitDate: Sun Sep 11 15:56:25 2011 +0300

    mtd: add MEMWRITE ioctl
    
    Implement a new ioctl for writing both page data and OOB to flash at the
    same time. This ioctl is intended to be a generic interface that can
    replace other ioctls (MEMWRITEOOB and MEMWRITEOOB64) and cover the
    functionality of several other old ones, e.g., MEMWRITE can:
    
    * write autoplaced OOB instead of using ECCGETLAYOUT (deprecated) and
      working around the reserved areas
    * write raw (no ECC) OOB instead of using MTDFILEMODE to set the
      per-file-descriptor MTD_FILE_MODE_RAW
    * write raw (no ECC) data instead of using MTDFILEMODE
      (MTD_FILE_MODE_RAW) and using standard character device "write"
    
    This ioctl is especially useful for MLC NAND, which cannot be written
    twice (i.e., we cannot successfully write the page data and OOB in two
    separate operations). Instead, MEMWRITE can write both in a single
    operation.
    
    Note that this ioctl is not affected by the MTD file mode (i.e.,
    MTD_FILE_MODE_RAW vs. MTD_FILE_MODE_NORMAL), since it receives its write
    mode as an input parameter.
    
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
    Signed-off-by: Artem Bityutskiy <artem.bityutskiy at intel.com>
---
 drivers/mtd/mtdchar.c |   56 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/mtd/mtd-abi.h |   11 +++++++++
 2 files changed, 67 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 4004f2b..1547e2a 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -566,6 +566,55 @@ static int mtd_blkpg_ioctl(struct mtd_info *mtd,
 	}
 }
 
+static int mtd_write_ioctl(struct mtd_info *mtd,
+		struct mtd_write_req __user *argp)
+{
+	struct mtd_write_req req;
+	struct mtd_oob_ops ops;
+	void __user *usr_data, *usr_oob;
+	int ret;
+
+	if (copy_from_user(&req, argp, sizeof(req)) ||
+			!access_ok(VERIFY_READ, req.usr_data, req.len) ||
+			!access_ok(VERIFY_READ, req.usr_oob, req.ooblen))
+		return -EFAULT;
+	if (!mtd->write_oob)
+		return -EOPNOTSUPP;
+
+	ops.mode = req.mode;
+	ops.len = (size_t)req.len;
+	ops.ooblen = (size_t)req.ooblen;
+	ops.ooboffs = 0;
+
+	usr_data = (void __user *)(uintptr_t)req.usr_data;
+	usr_oob = (void __user *)(uintptr_t)req.usr_oob;
+
+	if (req.usr_data) {
+		ops.datbuf = memdup_user(usr_data, ops.len);
+		if (IS_ERR(ops.datbuf))
+			return PTR_ERR(ops.datbuf);
+	} else {
+		ops.datbuf = NULL;
+	}
+
+	if (req.usr_oob) {
+		ops.oobbuf = memdup_user(usr_oob, ops.ooblen);
+		if (IS_ERR(ops.oobbuf)) {
+			kfree(ops.datbuf);
+			return PTR_ERR(ops.oobbuf);
+		}
+	} else {
+		ops.oobbuf = NULL;
+	}
+
+	ret = mtd->write_oob(mtd, (loff_t)req.start, &ops);
+
+	kfree(ops.datbuf);
+	kfree(ops.oobbuf);
+
+	return ret;
+}
+
 static int mtd_ioctl(struct file *file, u_int cmd, u_long arg)
 {
 	struct mtd_file_info *mfi = file->private_data;
@@ -753,6 +802,13 @@ static int mtd_ioctl(struct file *file, u_int cmd, u_long arg)
 		break;
 	}
 
+	case MEMWRITE:
+	{
+		ret = mtd_write_ioctl(mtd,
+		      (struct mtd_write_req __user *)arg);
+		break;
+	}
+
 	case MEMLOCK:
 	{
 		struct erase_info_user einfo;
diff --git a/include/mtd/mtd-abi.h b/include/mtd/mtd-abi.h
index 1885aa9..1a16046 100644
--- a/include/mtd/mtd-abi.h
+++ b/include/mtd/mtd-abi.h
@@ -60,6 +60,16 @@ enum {
 	MTD_OPS_RAW = 2,
 };
 
+struct mtd_write_req {
+	__u64 start;
+	__u64 len;
+	__u64 ooblen;
+	__u64 usr_data;
+	__u64 usr_oob;
+	__u8 mode;
+	__u8 padding[7];
+};
+
 #define MTD_ABSENT		0
 #define MTD_RAM			1
 #define MTD_ROM			2
@@ -147,6 +157,7 @@ struct otp_info {
 #define MEMWRITEOOB64		_IOWR('M', 21, struct mtd_oob_buf64)
 #define MEMREADOOB64		_IOWR('M', 22, struct mtd_oob_buf64)
 #define MEMISLOCKED		_IOR('M', 23, struct erase_info_user)
+#define MEMWRITE		_IOWR('M', 24, struct mtd_write_req)
 
 /*
  * Obsolete legacy interface. Keep it in order not to break userspace