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-rw-r--r--arch/powerpc/mm/vphn.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/arch/powerpc/mm/vphn.c b/arch/powerpc/mm/vphn.c
new file mode 100644
index 000000000000..5f8ef50e5c66
--- /dev/null
+++ b/arch/powerpc/mm/vphn.c
@@ -0,0 +1,70 @@
+#include <asm/byteorder.h>
+#include "vphn.h"
+
+/*
+ * The associativity domain numbers are returned from the hypervisor as a
+ * stream of mixed 16-bit and 32-bit fields. The stream is terminated by the
+ * special value of "all ones" (aka. 0xffff) and its size may not exceed 48
+ * bytes.
+ *
+ * --- 16-bit fields -->
+ * _________________________
+ * | 0 | 1 | 2 | 3 | be_packed[0]
+ * ------+-----+-----+------
+ * _________________________
+ * | 4 | 5 | 6 | 7 | be_packed[1]
+ * -------------------------
+ * ...
+ * _________________________
+ * | 20 | 21 | 22 | 23 | be_packed[5]
+ * -------------------------
+ *
+ * Convert 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;
+ u16 last = 0;
+ bool is_32bit = false;
+
+#define VPHN_FIELD_UNUSED (0xffff)
+#define VPHN_FIELD_MSB (0x8000)
+#define VPHN_FIELD_MASK (~VPHN_FIELD_MSB)
+
+ /* Let's fix the values returned by plpar_hcall9() */
+ for (i = 0; i < VPHN_REGISTER_COUNT; i++)
+ be_packed[i] = cpu_to_be64(packed[i]);
+
+ for (i = 1; i < VPHN_ASSOC_BUFSIZE; i++) {
+ u16 new = be16_to_cpup(field++);
+
+ if (is_32bit) {
+ /* Let's concatenate the 16 bits of this field to the
+ * 15 lower bits of the previous field
+ */
+ unpacked[++nr_assoc_doms] =
+ cpu_to_be32(last << 16 | new);
+ is_32bit = false;
+ } else if (new == VPHN_FIELD_UNUSED)
+ /* This is the list terminator */
+ break;
+ else if (new & VPHN_FIELD_MSB) {
+ /* Data is in the lower 15 bits of this field */
+ unpacked[++nr_assoc_doms] =
+ cpu_to_be32(new & VPHN_FIELD_MASK);
+ } else {
+ /* Data is in the lower 15 bits of this field
+ * concatenated with the next 16 bit field
+ */
+ last = new;
+ is_32bit = true;
+ }
+ }
+
+ /* The first cell contains the length of the property */
+ unpacked[0] = cpu_to_be32(nr_assoc_doms);
+
+ return nr_assoc_doms;
+}