Reverts bad change to mtd-rw

src/main.zig

@@ -10,25 +10,30 @@ pub fn main() !u8 {
     try mtd_rw.load();
     defer mtd_rw.unload();
 
-    try mtd.ensure_size("mtd0", uboot_bin.len);
+    const mtd_dev = "/dev/mtd0";
 
-    const no_write_needed = try mtd.verify("/dev/mtd0", uboot_bin);
+    // Ensure the partition is large enough to hold the new data
+    try mtd.ensure_size(mtd_dev, uboot_bin.len);
+
+    // Bail if the partition matches our payload already
+    const no_write_needed = try mtd.verify(mtd_dev, uboot_bin);
     if (no_write_needed) {
         std.debug.warn("U-Boot is up to date. Exiting.\n", .{});
         return 0;
     }
 
+    // Erase and Write
+    try mtd.erase_device(mtd_dev);
+    std.debug.warn("Writing {} bytes to {}\n", .{uboot_bin.len, mtd_dev});
+    try mtd.write_device(mtd_dev, uboot_bin);
 
-    try mtd.erase_device("/dev/mtd0");
-    std.debug.warn("Writing {} bytes to /dev/mtd0\n", .{uboot_bin.len});
-    try mtd.write_device("/dev/mtd0", uboot_bin);
-
-    // Verify mtd0
-    const writing_verified = try mtd.verify("/dev/mtd0", uboot_bin);
+    // Verify
+    const writing_verified = try mtd.verify(mtd_dev, uboot_bin);
     if (!writing_verified) {
         std.debug.warn("Verify Failed!\n", .{});
         return 2;
     }
+
     std.debug.warn("Success\n", .{});
     return 0;
 }

src/mtd-rw.zig

@@ -13,7 +13,6 @@ const InitModuleError = error {
     AlreadyLoaded,
     BadParams,
     InvalidModule,
-
 };
 
 const DeleteModuleError = error {
@@ -37,7 +36,7 @@ pub fn unload() void {
 pub fn insmod(buf: []const u8, args: [*:0]const u8) !void {
     const errno = os.linux.getErrno(
         os.linux.syscall3(
-            os.linux.SYS_init_module, @ptrToInt(&buf), buf.len, @ptrToInt(args)));
+            os.linux.SYS_init_module, @ptrToInt(&buf[0]), buf.len, @ptrToInt(args)));
     switch (errno) {
         0 => return,
         os.EEXIST => return, // Module already loaded, this is fine

src/mtd.zig

@@ -8,9 +8,10 @@ const Allocator = std.heap.c_allocator;
 const MEMUNLOCK = 2148027654;
 const MEMERASE =  2148027650;
 
-pub fn mtd_info_get(name: []const u8, out: []u8) !void {
+pub fn mtd_info_get(dev: []const u8, name: []const u8, out: []u8) !void {
+    const nonabs = dev[5..];
     var path_buf: [64]u8 = undefined;
-    const path = try std.fmt.bufPrint(path_buf[0..], "{}/{}", .{"/sys/class/mtd/mtd0/", name});
+    const path = try std.fmt.bufPrint(path_buf[0..], "{}/{}/{}", .{"/sys/class/mtd", nonabs, name});
 
     var f = try std.fs.openFileAbsolute(path, .{.read = true});
     defer f.close();
@@ -18,10 +19,10 @@ pub fn mtd_info_get(name: []const u8, out: []u8) !void {
     out = out[0..num_read-1];
 }
 
-pub fn mtd_info_get_usize(name: []const u8) !usize {
+pub fn mtd_info_get_usize(dev: []const u8, name: []const u8) !usize {
     var buf: [64]u8 = undefined;
     var buf_sl = buf[0..];
-    try mtd_info_get(name, buf_sl);
+    try mtd_info_get(dev, name, buf_sl);
     return try std.fmt.parseUnsigned(usize, buf_sl, 10);
 }
 
@@ -57,7 +58,7 @@ const MtdError = error {
 };
 
 pub fn ensure_size(dev: []const u8, size: usize) !void {
-    const part_size = try mtd_info_get_usize("size");
+    const part_size = try mtd_info_get_usize(dev, "size");
     if (size > part_size) {
          std.debug.warn("Error: {} isn\'t large enough to hold the new image ({} > {})\n",
                         .{dev, size, part_size});
@@ -72,8 +73,8 @@ pub fn write_device(dev: []const u8, buf: []const u8) !void {
 }
 
 pub fn erase_device(dev: []const u8) !void {
-    const erasesize = try mtd_info_get_usize("erasesize");
-    const size = try mtd_info_get_usize("size");
+    const erasesize = try mtd_info_get_usize(dev, "erasesize");
+    const size = try mtd_info_get_usize(dev, "size");
     var erased: usize = 0;
     const fd = try os.open(dev, os.O_RDWR, 0);
     defer os.close(fd);
@@ -92,7 +93,7 @@ pub fn erase_page(fd: os.fd_t, start: usize, len: usize) !void {
 }
 
 pub fn verify(dev: []const u8, buf: []const u8) !bool {
-    const size = try mtd_info_get_usize("size");
+    const size = try mtd_info_get_usize(dev, "size");
     var current = try Allocator.alloc(u8, size);
 
     var f = try std.fs.openFileAbsolute(dev, .{.read = true});