dev-arm: Define enum masks for SMMU_CR0 register

The configuration register is a vital register in the SMMU, and using
enum masks will make the code more readable/understandable

Change-Id: Ia117db56c457fe876ae38be391c386e502f34384
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Michiel Van Tol <michiel.vantol@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19632
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/dev/arm/smmu_v3_defs.hh

@@ -311,6 +311,15 @@ struct ContextDescriptor
     uint64_t _pad[3];
 };
 
+enum {
+    CR0_SMMUEN_MASK = 0x1,
+    CR0_PRIQEN_MASK = 0x2,
+    CR0_EVENTQEN_MASK = 0x4,
+    CR0_CMDQEN_MASK = 0x8,
+    CR0_ATSCHK_MASK = 0x10,
+    CR0_VMW_MASK = 0x1C0,
+};
+
 enum SMMUCommandType {
     CMD_PRF_CONFIG   = 0x1000,
     CMD_PRF_ADDR     = 0x1001,

src/dev/arm/smmu_v3_transl.cc

@@ -155,8 +155,7 @@ SMMUTranslationProcess::main(Yield &yield)
 
     recvTick = curTick();
 
-
-    if (!(smmu.regs.cr0 & 0x1)) {
+    if (!(smmu.regs.cr0 & CR0_SMMUEN_MASK)) {
         // SMMU disabled
         doDelay(yield, Cycles(1));
         completeTransaction(yield, bypass(request.addr));