hw/misc/iotkit-sysctl: Implement dummy version of SSE-300 PWRCTRL register

The SSE-300 has a new PWRCTRL register at offset 0x1fc (previously
reserved). This register controls accessibility of some registers
in the Power Policy Units (PPUs). Since QEMU doesn't implement
the PPUs, we don't need to implement any real behaviour for this
register, so we just handle the UNLOCK bit which controls whether
writes to the register itself are permitted and otherwise make it
be reads-as-written.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210219144617.4782-17-peter.maydell@linaro.org

2 files changed, 53 insertions, 0 deletions

diff --git a/hw/misc/iotkit-sysctl.c b/hw/misc/iotkit-sysctl.c
index 511ede089c..9ec02c3e94 100644
--- a/hw/misc/iotkit-sysctl.c
+++ b/hw/misc/iotkit-sysctl.c
@@ -52,6 +52,9 @@ REG32(CPUWAIT, 0x118)
 REG32(NMI_ENABLE, 0x11c) /* BUSWAIT in IoTKit */
 REG32(WICCTRL, 0x120)
 REG32(EWCTRL, 0x124)
+REG32(PWRCTRL, 0x1fc)
+    FIELD(PWRCTRL, PPU_ACCESS_UNLOCK, 0, 1)
+    FIELD(PWRCTRL, PPU_ACCESS_FILTER, 1, 1)
 REG32(PDCM_PD_SYS_SENSE, 0x200)
 REG32(PDCM_PD_SRAM0_SENSE, 0x20c)
 REG32(PDCM_PD_SRAM1_SENSE, 0x210)
@@ -233,6 +236,18 @@ static uint64_t iotkit_sysctl_read(void *opaque, hwaddr offset,
             g_assert_not_reached();
         }
         break;
+    case A_PWRCTRL:
+        switch (s->sse_version) {
+        case ARMSSE_IOTKIT:
+        case ARMSSE_SSE200:
+            goto bad_offset;
+        case ARMSSE_SSE300:
+            r = s->pwrctrl;
+            break;
+        default:
+            g_assert_not_reached();
+        }
+        break;
     case A_PDCM_PD_SYS_SENSE:
         switch (s->sse_version) {
         case ARMSSE_IOTKIT:
@@ -508,6 +523,23 @@ static void iotkit_sysctl_write(void *opaque, hwaddr offset,
             g_assert_not_reached();
         }
         break;
+    case A_PWRCTRL:
+        switch (s->sse_version) {
+        case ARMSSE_IOTKIT:
+        case ARMSSE_SSE200:
+            goto bad_offset;
+        case ARMSSE_SSE300:
+            if (!(s->pwrctrl & R_PWRCTRL_PPU_ACCESS_UNLOCK_MASK)) {
+                qemu_log_mask(LOG_GUEST_ERROR,
+                              "IoTKit PWRCTRL write when register locked\n");
+                break;
+            }
+            s->pwrctrl = value;
+            break;
+        default:
+            g_assert_not_reached();
+        }
+        break;
     case A_PDCM_PD_SYS_SENSE:
         switch (s->sse_version) {
         case ARMSSE_IOTKIT:
@@ -635,6 +667,7 @@ static void iotkit_sysctl_reset(DeviceState *dev)
     s->clock_force = 0;
     s->nmi_enable = 0;
     s->ewctrl = 0;
+    s->pwrctrl = 0x3;
     s->pdcm_pd_sys_sense = 0x7f;
     s->pdcm_pd_sram0_sense = 0;
     s->pdcm_pd_sram1_sense = 0;
@@ -662,6 +695,24 @@ static void iotkit_sysctl_realize(DeviceState *dev, Error **errp)
     }
 }
 
+static bool sse300_needed(void *opaque)
+{
+    IoTKitSysCtl *s = IOTKIT_SYSCTL(opaque);
+
+    return s->sse_version == ARMSSE_SSE300;
+}
+
+static const VMStateDescription iotkit_sysctl_sse300_vmstate = {
+    .name = "iotkit-sysctl/sse-300",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = sse300_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(pwrctrl, IoTKitSysCtl),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static bool sse200_needed(void *opaque)
 {
     IoTKitSysCtl *s = IOTKIT_SYSCTL(opaque);
@@ -706,6 +757,7 @@ static const VMStateDescription iotkit_sysctl_vmstate = {
     },
     .subsections = (const VMStateDescription*[]) {
         &iotkit_sysctl_sse200_vmstate,
+        &iotkit_sysctl_sse300_vmstate,
         NULL
     }
 };
diff --git a/include/hw/misc/iotkit-sysctl.h b/include/hw/misc/iotkit-sysctl.h
index 980c2ddfd3..8859b15d73 100644
--- a/include/hw/misc/iotkit-sysctl.h
+++ b/include/hw/misc/iotkit-sysctl.h
@@ -53,6 +53,7 @@ struct IoTKitSysCtl {
     uint32_t initsvtor1;
     uint32_t nmi_enable;
     uint32_t ewctrl;
+    uint32_t pwrctrl;
     uint32_t pdcm_pd_sys_sense;
     uint32_t pdcm_pd_sram0_sense;
     uint32_t pdcm_pd_sram1_sense;