new file mode 100644
@@ -0,0 +1,29 @@
+/*
+ * FSI CRC calculator
+ *
+ * Copyright (C) IBM Corporation 2016
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ *
+ * Implements the standard FSI CRC:
+ *
+ * Width 1 - 32
+ * Poly 0x0017 (x^4 + x^2 + x^1 + x^0)
+ */
+
+#ifndef CRC_FSI_H
+#define CRC_FSI_H
+
+#include <linux/types.h>
+
+uint8_t crc_fsi(uint8_t c, uint64_t x, int bits);
+
+#endif /* CRC_FSI_H */
@@ -230,3 +230,4 @@ obj-$(CONFIG_UBSAN) += ubsan.o
UBSAN_SANITIZE_ubsan.o := n
obj-$(CONFIG_SBITMAP) += sbitmap.o
+obj-$(CONFIG_FSI) += crc-fsi.o
new file mode 100644
@@ -0,0 +1,39 @@
+/*
+ * FSI CRC calculator
+ *
+ * Copyright (C) IBM Corporation 2016
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/crc-fsi.h>
+
+/* crc helpers */
+static const uint8_t crc_fsi_tab[] = {
+ 0x0, 0x7, 0xe, 0x9, 0xb, 0xc, 0x5, 0x2,
+ 0x1, 0x6, 0xf, 0x8, 0xa, 0xd, 0x4, 0x3,
+};
+
+uint8_t crc_fsi(uint8_t c, uint64_t x, int bits)
+{
+ int i;
+
+ /* Align to 4-bits */
+ bits = (bits + 3) & ~0x3;
+
+ /* Calculate crc4 over four-bit nibbles, starting at the MSbit */
+ for (i = bits; i >= 0; i -= 4)
+ c = crc_fsi_tab[c ^ ((x >> i) & 0xf)];
+
+ return c;
+}
+EXPORT_SYMBOL_GPL(crc_fsi);