powerpc/vphn: move VPHN parsing logic to a separate file

The goal behind this patch is to be able to write userland tests for the
VPHN parsing code.

Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 50 insertions, 0 deletions

diff --git a/arch/powerpc/mm/vphn.c b/arch/powerpc/mm/vphn.c
new file mode 100644
index 000000000000..c49ed519c381
--- /dev/null
+++ b/arch/powerpc/mm/vphn.c
@@ -0,0 +1,50 @@
+#include <asm/byteorder.h>
+#include "vphn.h"
+
+/*
+ * Convert the associativity domain numbers returned from the hypervisor
+ * to the sequence they would appear in the ibm,associativity property.
+ */
+int vphn_unpack_associativity(const long *packed, __be32 *unpacked)
+{
+	__be64 be_packed[VPHN_REGISTER_COUNT];
+	int i, nr_assoc_doms = 0;
+	const __be16 *field = (const __be16 *) be_packed;
+
+#define VPHN_FIELD_UNUSED	(0xffff)
+#define VPHN_FIELD_MSB		(0x8000)
+#define VPHN_FIELD_MASK		(~VPHN_FIELD_MSB)
+
+	/* Let's recreate the original stream. */
+	for (i = 0; i < VPHN_REGISTER_COUNT; i++)
+		be_packed[i] = cpu_to_be64(packed[i]);
+
+	for (i = 1; i < VPHN_ASSOC_BUFSIZE; i++) {
+		if (be16_to_cpup(field) == VPHN_FIELD_UNUSED) {
+			/* All significant fields processed, and remaining
+			 * fields contain the reserved value of all 1's.
+			 * Just store them.
+			 */
+			unpacked[i] = *((__be32 *)field);
+			field += 2;
+		} else if (be16_to_cpup(field) & VPHN_FIELD_MSB) {
+			/* Data is in the lower 15 bits of this field */
+			unpacked[i] = cpu_to_be32(
+				be16_to_cpup(field) & VPHN_FIELD_MASK);
+			field++;
+			nr_assoc_doms++;
+		} else {
+			/* Data is in the lower 15 bits of this field
+			 * concatenated with the next 16 bit field
+			 */
+			unpacked[i] = *((__be32 *)field);
+			field += 2;
+			nr_assoc_doms++;
+		}
+	}
+
+	/* The first cell contains the length of the property */
+	unpacked[0] = cpu_to_be32(nr_assoc_doms);
+
+	return nr_assoc_doms;
+}