From 75dff45fcb62b2ff047f5a4cc22bb602c766c95b Mon Sep 17 00:00:00 2001
From: d0k3 <tore.anon@gmail.com>
Date: Wed, 2 Mar 2016 20:01:13 +0100
Subject: [PATCH] Use alternate method of getting NAND CTR (via NAND CID)

---
 source/fatfs/diskio.c | 32 +++++++++++++++++++++++++++++++-
 source/fatfs/sha.c    | 32 ++++++++++++++++++++++++++++++++
 source/fatfs/sha.h    | 27 +++++++++++++++++++++++++++
 3 files changed, 90 insertions(+), 1 deletion(-)
 create mode 100644 source/fatfs/sha.c
 create mode 100644 source/fatfs/sha.h

diff --git a/source/fatfs/diskio.c b/source/fatfs/diskio.c
index 166b172..666925f 100644
--- a/source/fatfs/diskio.c
+++ b/source/fatfs/diskio.c
@@ -9,6 +9,7 @@
 
 #include "diskio.h"		/* FatFs lower layer API */
 #include "aes.h"
+#include "sha.h"
 #include "platform.h"
 #include "sdmmc.h"
 
@@ -65,7 +66,7 @@ static u32 emunand_base_sector = 0x000000;
 /* Get counter for NAND AES decryption                                    */
 /*-----------------------------------------------------------------------*/
 
-u32 GetNandCtr(u8* ctr, u32 sector)
+/*u32 GetNandCtr(u8* ctr, u32 sector)
 {
     static const u8* version_ctrs[] = {
         (u8*)0x080D7CAC,
@@ -112,6 +113,35 @@ u32 GetNandCtr(u8* ctr, u32 sector)
     // increment counter
     add_ctr(ctr, sector * (0x200/0x10));
 
+    return 0;
+}*/
+
+u32 GetNandCtr(u8* ctr, u32 sector)
+{
+    static u8* NandCid = NULL;
+    static u8 CtrNandCtr[16];
+    static u8 TwlNandCtr[16];
+    
+    if (!NandCid) {
+        NandCid = (u8*) 0x01FFCD84;
+        u8 shasum[32];
+        sha_init(SHA256_MODE);
+        sha_update(NandCid, 16);
+        sha_get(shasum);
+        memcpy(CtrNandCtr, shasum, 16);
+        sha_init(SHA1_MODE);
+        sha_update(NandCid, 16);
+        sha_get(shasum);
+        for(u32 i = 0; i < 16; i++) // little endian and reversed order
+            TwlNandCtr[i] = shasum[15-i];
+    }
+    
+    // copy NAND CTR over
+    memcpy(ctr, (sector >= (0x0B100000 / 0x200)) ? CtrNandCtr : TwlNandCtr, 16);
+    
+    // increment counter
+    add_ctr(ctr, sector * (0x200/0x10));
+
     return 0;
 }
 
diff --git a/source/fatfs/sha.c b/source/fatfs/sha.c
new file mode 100644
index 0000000..0902ddc
--- /dev/null
+++ b/source/fatfs/sha.c
@@ -0,0 +1,32 @@
+#include "sha.h"
+
+void sha_init(u32 mode)
+{
+    while(*REG_SHACNT & 1);
+    *REG_SHACNT = mode | SHA_CNT_OUTPUT_ENDIAN | SHA_NORMAL_ROUND;
+}
+
+void sha_update(const void* src, u32 size)
+{    
+    const u32* src32 = (const u32*)src;
+    
+    while(size >= 0x40) {
+        while(*REG_SHACNT & 1);
+        for(u32 i = 0; i < 4; i++) {
+            *REG_SHAINFIFO = *src32++;
+            *REG_SHAINFIFO = *src32++;
+            *REG_SHAINFIFO = *src32++;
+            *REG_SHAINFIFO = *src32++;
+        }
+        size -= 0x40;
+    }
+    while(*REG_SHACNT & 1);
+    memcpy((void*)REG_SHAINFIFO, src32, size);
+}
+
+void sha_get(void* res) {
+    *REG_SHACNT = (*REG_SHACNT & ~SHA_NORMAL_ROUND) | SHA_FINAL_ROUND;
+    while(*REG_SHACNT & SHA_FINAL_ROUND);
+    while(*REG_SHACNT & 1);
+    memcpy(res, (void*)REG_SHAHASH, (256 / 8));
+}
diff --git a/source/fatfs/sha.h b/source/fatfs/sha.h
new file mode 100644
index 0000000..cb88d42
--- /dev/null
+++ b/source/fatfs/sha.h
@@ -0,0 +1,27 @@
+#pragma once
+
+#include "common.h"
+
+#define REG_SHACNT      ((volatile uint32_t*)0x1000A000)
+#define REG_SHABLKCNT   ((volatile uint32_t*)0x1000A004)
+#define REG_SHAHASH     ((volatile uint32_t*)0x1000A040)
+#define REG_SHAINFIFO   ((volatile uint32_t*)0x1000A080)
+
+#define SHA_CNT_STATE           0x00000003
+#define SHA_CNT_OUTPUT_ENDIAN   0x00000008
+#define SHA_CNT_MODE            0x00000030
+#define SHA_CNT_ENABLE          0x00010000
+#define SHA_CNT_ACTIVE          0x00020000
+
+#define SHA_HASH_READY          0x00000000
+#define SHA_NORMAL_ROUND        0x00000001
+#define SHA_FINAL_ROUND         0x00000002
+
+#define SHA256_MODE             0
+#define SHA224_MODE             0x00000010
+#define SHA1_MODE               0x00000020
+
+
+void sha_init(u32 mode);
+void sha_update(const void* src, u32 size);
+void sha_get(void* res);