hw/cxl/component: Add utils for interleave parameter encoding/decoding

Both registers and the CFMWS entries in CDAT use simple encodings
for the number of interleave ways and the interleave granularity.
Introduce simple conversion functions to/from the unencoded
number / size.  So far the iw decode has not been needed so is
it not implemented.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-27-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/cxl/cxl-component-utils.c

@@ -9,6 +9,7 @@
 
 #include "qemu/osdep.h"
 #include "qemu/log.h"
+#include "qapi/error.h"
 #include "hw/pci/pci.h"
 #include "hw/cxl/cxl.h"
 
@@ -329,3 +330,36 @@ void cxl_component_create_dvsec(CXLComponentState *cxl,
     range_init_nofail(&cxl->dvsecs[type], cxl->dvsec_offset, length);
     cxl->dvsec_offset += length;
 }
+
+uint8_t cxl_interleave_ways_enc(int iw, Error **errp)
+{
+    switch (iw) {
+    case 1: return 0x0;
+    case 2: return 0x1;
+    case 4: return 0x2;
+    case 8: return 0x3;
+    case 16: return 0x4;
+    case 3: return 0x8;
+    case 6: return 0x9;
+    case 12: return 0xa;
+    default:
+        error_setg(errp, "Interleave ways: %d not supported", iw);
+        return 0;
+    }
+}
+
+uint8_t cxl_interleave_granularity_enc(uint64_t gran, Error **errp)
+{
+    switch (gran) {
+    case 256: return 0;
+    case 512: return 1;
+    case 1024: return 2;
+    case 2048: return 3;
+    case 4096: return 4;
+    case 8192: return 5;
+    case 16384: return 6;
+    default:
+        error_setg(errp, "Interleave granularity: %" PRIu64 " invalid", gran);
+        return 0;
+    }
+}

include/hw/cxl/cxl_component.h

@@ -210,4 +210,12 @@ static inline int cxl_decoder_count_enc(int count)
     return 0;
 }
 
+uint8_t cxl_interleave_ways_enc(int iw, Error **errp);
+uint8_t cxl_interleave_granularity_enc(uint64_t gran, Error **errp);
+
+static inline hwaddr cxl_decode_ig(int ig)
+{
+    return 1 << (ig + 8);
+}
+
 #endif