hw/arm/armsse: Introduce SSE subsystem version property

We model Arm "Subsystems for Embedded" SoC subsystems using generic
code which is split into various sub-devices which are configurable
by QOM properties to handle the behaviour differences between the SSE
subsystems we implement.  Currently the only sub-device which needs
to change is the IOTKIT_SYSCTL device, and we do this with a mix of
properties that directly specify divergent behaviours (eg
CPUWAIT_RST) and passing it the SYS_VERSION register value as a way
for it to distinguish IoTKit from SSE-200.

The "pass SYS_VERSION" approach is already a bit hacky, since the
IOTKIT_SYSCTL device has to know that the different part of the
register value happens to be bits [31:28].  For SSE-300 this register
is renamed SOC_IDENTITY and has a different format entirely, all of
whose fields can be configured by the SoC integrator when they
integrate the SSE into their SoC, and so "pass SYS_VERSION" breaks
down completely.

Switch to using a simple integer property representing an
internal-to-QEMU enumeration of the SSE flavour.  For the moment we
only need this in IOTKIT_SYSCTL, but as we add SSE-300 support a few
of the other devices will also need to know.

We define and permit a value for the SSE-300 so we can start using
it in subsequent commits which add SSE-300 support.

The now-redundant is_sse200 flag in IoTKitSysCtl will be removed
in the following commit.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
I didn't use a full-on qdev/QOM 'enum' property here because that
requires messing with the QAPI schema, which seems like overkill for
this entirely-internal-to-the-implementation bit of information
passing.

1 files changed, 7 insertions, 4 deletions

diff --git a/hw/misc/iotkit-sysctl.c b/hw/misc/iotkit-sysctl.c
index 222511c4b0..34b37fe882 100644
--- a/hw/misc/iotkit-sysctl.c
+++ b/hw/misc/iotkit-sysctl.c
@@ -28,6 +28,7 @@
 #include "hw/registerfields.h"
 #include "hw/misc/iotkit-sysctl.h"
 #include "hw/qdev-properties.h"
+#include "hw/arm/armsse-version.h"
 #include "target/arm/arm-powerctl.h"
 #include "target/arm/cpu.h"
 
@@ -438,10 +439,12 @@ static void iotkit_sysctl_realize(DeviceState *dev, Error **errp)
 {
     IoTKitSysCtl *s = IOTKIT_SYSCTL(dev);
 
-    /* The top 4 bits of the SYS_VERSION register tell us if we're an SSE-200 */
-    if (extract32(s->sys_version, 28, 4) == 2) {
-        s->is_sse200 = true;
+    if (!armsse_version_valid(s->sse_version)) {
+        error_setg(errp, "invalid sse-version value %d", s->sse_version);
+        return;
     }
+
+    s->is_sse200 = s->sse_version == ARMSSE_SSE200;
 }
 
 static bool sse200_needed(void *opaque)
@@ -493,7 +496,7 @@ static const VMStateDescription iotkit_sysctl_vmstate = {
 };
 
 static Property iotkit_sysctl_props[] = {
-    DEFINE_PROP_UINT32("SYS_VERSION", IoTKitSysCtl, sys_version, 0),
+    DEFINE_PROP_UINT32("sse-version", IoTKitSysCtl, sse_version, 0),
     DEFINE_PROP_UINT32("CPUWAIT_RST", IoTKitSysCtl, cpuwait_rst, 0),
     DEFINE_PROP_UINT32("INITSVTOR0_RST", IoTKitSysCtl, initsvtor0_rst,
                        0x10000000),