libffs: Add ECC checking code

Add ECC checking code.  This code is based on the hostboot code.

Unused currently, but will be soon.  This uses __builtin_parityl() hence adding
libgcc linking previously.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/include/ecc.h b/include/ecc.h
new file mode 100644
index 0000000..d5c30cb
--- /dev/null
+++ b/include/ecc.h
@@ -0,0 +1,53 @@
+/* Copyright 2013-2014 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * 	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* This is based on the hostboot ecc code */
+
+#ifndef __ECC_H
+#define __ECC_H
+
+#include <stdint.h>
+#include <skiboot.h>
+
+/* Bit field identifiers for syndrome calculations. */
+enum eccbitfields
+{
+        GD = 0xff,      //< Good, ECC matches.
+        UE = 0xfe,      //< Uncorrectable.
+        E0 = 71,        //< Error in ECC bit 0
+        E1 = 70,        //< Error in ECC bit 1
+        E2 = 69,        //< Error in ECC bit 2
+        E3 = 68,        //< Error in ECC bit 3
+        E4 = 67,        //< Error in ECC bit 4
+        E5 = 66,        //< Error in ECC bit 5
+        E6 = 65,        //< Error in ECC bit 6
+        E7 = 64         //< Error in ECC bit 7
+};
+
+extern uint8_t eccmemcpy(uint64_t *dst, uint64_t *src, uint32_t len);
+
+/*
+ * Calculate the size of a buffer if ECC is added
+ *
+ * We add 1 byte of ecc for every 8 bytes of data.  So we need to round up to 8
+ * bytes length and then add 1/8
+ */
+#define ECC_SIZE(len) (ALIGN_UP((len), 8) >> 3)
+#define ECC_BUFFER_SIZE(len) (ALIGN_UP((len), 8) + ECC_SIZE(len))
+#define ECC_BUFFER_SIZE_CHECK(len) ((len) % 9)
+#define BUFFER_SIZE_MINUS_ECC(len) ((len) * 8 / 9)
+
+#endif