[MTD] User interface to Protection Registers

This is implemented using a ioctl to switch the MTD char device into
one of the different OTP "modes", at which point read/write/seek can
operate on the selected OTP area.  Also some extra ioctls to query
for size and lock protection segments or groups.  Some example user
space utilities are provided.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 110 insertions, 3 deletions

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 510ad78312cc..6ea2d8058a4a 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -1,5 +1,5 @@
 /*
- * $Id: mtdchar.c,v 1.66 2005/01/05 18:05:11 dwmw2 Exp $
+ * $Id: mtdchar.c,v 1.67 2005/02/08 17:45:51 nico Exp $
  *
  * Character-device access to raw MTD devices.
  *
@@ -59,6 +59,12 @@ static inline void mtdchar_devfs_exit(void)
 #define mtdchar_devfs_exit() do { } while(0)
 #endif
 
+
+/* Well... let's abuse the unused bits in file->f_mode for those */
+#define MTD_MODE_OTP_FACT       0x1000
+#define MTD_MODE_OTP_USER       0x2000
+#define MTD_MODE_MASK           0xf000
+
 static loff_t mtd_lseek (struct file *file, loff_t offset, int orig)
 {
         struct mtd_info *mtd = file->private_data;
@@ -105,6 +111,10 @@ static int mtd_open(struct inode *inode, struct file *file)
         if ((file->f_mode & 2) && (minor & 1))
                 return -EACCES;
 
+        /* make sure the locally abused bits are initialy clear */
+        if (file->f_mode & MTD_MODE_MASK)
+                return -EWOULDBLOCK;
+
         mtd = get_mtd_device(NULL, devnum);
         
         if (!mtd)
@@ -178,7 +188,16 @@ static ssize_t mtd_read(struct file *file, char __user *buf, size_t count,loff_t
                 if (!kbuf)
                         return -ENOMEM;
                 
-                ret = MTD_READ(mtd, *ppos, len, &retlen, kbuf);
+                switch (file->f_mode & MTD_MODE_MASK) {
+                case MTD_MODE_OTP_FACT:
+                        ret = mtd->read_fact_prot_reg(mtd, *ppos, len, &retlen, kbuf);
+                        break;
+                case MTD_MODE_OTP_USER:
+                        ret = mtd->read_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
+                        break;
+                default:
+                        ret = MTD_READ(mtd, *ppos, len, &retlen, kbuf);
+                }
                 /* Nand returns -EBADMSG on ecc errors, but it returns
                  * the data. For our userspace tools it is important
                  * to dump areas with ecc errors ! 
@@ -196,6 +215,8 @@ static ssize_t mtd_read(struct file *file, char __user *buf, size_t count,loff_t
 
                         count -= retlen;
                         buf += retlen;
+                        if (retlen == 0)
+                                count = 0;
                 }
                 else {
                         kfree(kbuf);
@@ -245,7 +266,20 @@ static ssize_t mtd_write(struct file *file, const char __user *buf, size_t count
                         return -EFAULT;
                 }
                 
-                ret = (*(mtd->write))(mtd, *ppos, len, &retlen, kbuf);
+                switch (file->f_mode & MTD_MODE_MASK) {
+                case MTD_MODE_OTP_FACT:
+                        ret = -EROFS;
+                        break;
+                case MTD_MODE_OTP_USER:
+                        if (!mtd->write_user_prot_reg) {
+                                ret = -EOPNOTSUPP;
+                                break;
+                        }
+                        ret = mtd->write_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
+                        break;
+                default:
+                        ret = (*(mtd->write))(mtd, *ppos, len, &retlen, kbuf);
+                }
                 if (!ret) {
                         *ppos += retlen;
                         total_retlen += retlen;
@@ -518,6 +552,79 @@ static int mtd_ioctl(struct inode *inode, struct file *file,
                 break;
         }
 
+#ifdef CONFIG_MTD_OTP
+        case OTPSELECT:
+        {
+                int mode;
+                if (copy_from_user(&mode, argp, sizeof(int)))
+                        return -EFAULT;
+                file->f_mode &= ~MTD_MODE_MASK;
+                switch (mode) {
+                case MTD_OTP_FACTORY:
+                        if (!mtd->read_fact_prot_reg)
+                                ret = -EOPNOTSUPP;
+                        else
+                                file->f_mode |= MTD_MODE_OTP_FACT;
+                        break;
+                case MTD_OTP_USER:
+                        if (!mtd->read_fact_prot_reg)
+                                ret = -EOPNOTSUPP;
+                        else
+                                file->f_mode |= MTD_MODE_OTP_USER;
+                        break;
+                default:
+                        ret = -EINVAL;
+                case MTD_OTP_OFF:
+                        break;
+                }
+                break;
+        }
+
+        case OTPGETREGIONCOUNT:
+        case OTPGETREGIONINFO:
+        {
+                struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
+                if (!buf)
+                        return -ENOMEM;
+                ret = -EOPNOTSUPP;
+                switch (file->f_mode & MTD_MODE_MASK) {
+                case MTD_MODE_OTP_FACT:
+                        if (mtd->get_fact_prot_info)
+                                ret = mtd->get_fact_prot_info(mtd, buf, 4096);
+                        break;
+                case MTD_MODE_OTP_USER:
+                        if (mtd->get_user_prot_info)
+                                ret = mtd->get_user_prot_info(mtd, buf, 4096);
+                        break;
+                }
+                if (ret >= 0) {
+                        if (cmd == OTPGETREGIONCOUNT) {
+                                int nbr = ret / sizeof(struct otp_info);
+                                ret = copy_to_user(argp, &nbr, sizeof(int));
+                        } else
+                                ret = copy_to_user(argp, buf, ret);
+                        if (ret)
+                                ret = -EFAULT;
+                }
+                kfree(buf);
+                break;
+        }
+
+        case OTPLOCK:
+        {
+                struct otp_info info;
+
+                if ((file->f_mode & MTD_MODE_MASK) != MTD_MODE_OTP_USER)
+                        return -EINVAL;
+                if (copy_from_user(&info, argp, sizeof(info)))
+                        return -EFAULT;
+                if (!mtd->lock_user_prot_reg)
+                        return -EOPNOTSUPP;
+                ret = mtd->lock_user_prot_reg(mtd, info.start, info.length);
+                break;
+        }
+#endif
+
         default:
                 ret = -ENOTTY;
         }