ppc/xive: add support for the END Event State Buffers

The Event Notification Descriptor (END) XIVE structure also contains
two Event State Buffers providing further coalescing of interrupts,
one for the notification event (ESn) and one for the escalation events
(ESe). A MMIO page is assigned for each to control the EOI through
loads only. Stores are not allowed.

The END ESBs are modeled through an object resembling the 'XiveSource'
It is stateless as the END state bits are backed into the XiveEND
structure under the XiveRouter and the MMIO accesses follow the same
rules as for the XiveSource ESBs.

END ESBs are not supported by the Linux drivers neither on OPAL nor on
sPAPR. Nevetherless, it provides a mean to study the question in the
future and validates a bit more the XIVE model.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
[dwg: Fold in a later fix for field access]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 21 insertions, 0 deletions

diff --git a/include/hw/ppc/xive.h b/include/hw/ppc/xive.h
index 4851d3b..014f64a 100644
--- a/include/hw/ppc/xive.h
+++ b/include/hw/ppc/xive.h
@@ -337,6 +337,27 @@ int xive_router_write_end(XiveRouter *xrtr, uint8_t end_blk, uint32_t end_idx,
                           XiveEND *end, uint8_t word_number);
 
 /*
+ * XIVE END ESBs
+ */
+
+#define TYPE_XIVE_END_SOURCE "xive-end-source"
+#define XIVE_END_SOURCE(obj) \
+    OBJECT_CHECK(XiveENDSource, (obj), TYPE_XIVE_END_SOURCE)
+
+typedef struct XiveENDSource {
+    DeviceState parent;
+
+    uint32_t        nr_ends;
+    uint8_t         block_id;
+
+    /* ESB memory region */
+    uint32_t        esb_shift;
+    MemoryRegion    esb_mmio;
+
+    XiveRouter      *xrtr;
+} XiveENDSource;
+
+/*
  * For legacy compatibility, the exceptions define up to 256 different
  * priorities. P9 implements only 9 levels : 8 active levels [0 - 7]
  * and the least favored level 0xFF.