hw/misc: Add a model for the ASPEED System Control Unit

The SCU is a collection of chip-level control registers that manage the
various functions supported by ASPEED SoCs. Typically the bits control
interactions with clocks, external hardware or reset behaviour, and we
can largly take a hands-off approach to reads and writes.

Firmware makes heavy use of the state to determine how to boot, but the
reset values vary from SoC to SoC (eg AST2400 vs AST2500). A qdev
property is exposed so that the integrating SoC model can configure the
silicon revision, which in-turn selects the appropriate reset values.
Further qdev properties are exposed so the board model can configure the
board-dependent hardware strapping.

Almost all provided AST2400 reset values are specified by the datasheet.
The notable exception is SOC_SCRATCH1, where we mark the DRAM as
successfully initialised to avoid unnecessary dark corners in the SoC's
u-boot support.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1466744305-23163-2-git-send-email-andrew@aj.id.au
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: drop unnecessary inttypes.h include]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/include/hw/misc/aspeed_scu.h b/include/hw/misc/aspeed_scu.h
new file mode 100644
index 0000000000..6b8e46f85f
--- /dev/null
+++ b/include/hw/misc/aspeed_scu.h
@@ -0,0 +1,34 @@
+/*
+ * ASPEED System Control Unit
+ *
+ * Andrew Jeffery <andrew@aj.id.au>
+ *
+ * Copyright 2016 IBM Corp.
+ *
+ * This code is licensed under the GPL version 2 or later.  See
+ * the COPYING file in the top-level directory.
+ */
+#ifndef ASPEED_SCU_H
+#define ASPEED_SCU_H
+
+#include "hw/sysbus.h"
+
+#define TYPE_ASPEED_SCU "aspeed.scu"
+#define ASPEED_SCU(obj) OBJECT_CHECK(AspeedSCUState, (obj), TYPE_ASPEED_SCU)
+
+#define ASPEED_SCU_NR_REGS (0x1A8 >> 2)
+
+typedef struct AspeedSCUState {
+    /*< private >*/
+    SysBusDevice parent_obj;
+
+    /*< public >*/
+    MemoryRegion iomem;
+
+    uint32_t regs[ASPEED_SCU_NR_REGS];
+    uint32_t silicon_rev;
+    uint32_t hw_strap1;
+    uint32_t hw_strap2;
+} AspeedSCUState;
+
+#endif /* ASPEED_SCU_H */