arm: Remove the 'magic MSI register' in the GIC (PL390)

This patch removes the code that added this magic register. A
follow-up patch provides a GICv2m MSI shim that gives the same
functionality in a standard ARM system architecture way.

src/dev/arm/Gic.py

@@ -54,7 +54,6 @@ class Pl390(BaseGic):
 
     dist_addr = Param.Addr(0x1f001000, "Address for distributor")
     cpu_addr = Param.Addr(0x1f000100, "Address for cpu")
-    msix_addr = Param.Addr(0x0, "Address for MSI-X register")
     dist_pio_delay = Param.Latency('10ns', "Delay for PIO r/w to distributor")
     cpu_pio_delay = Param.Latency('10ns', "Delay for PIO r/w to cpu interface")
     int_latency = Param.Latency('10ns', "Delay for interrupt to get to CPU")

src/dev/arm/gic_pl390.cc

@@ -55,9 +55,7 @@ Pl390::Pl390(const Params *p)
     : BaseGic(p), distAddr(p->dist_addr),
       cpuAddr(p->cpu_addr), distPioDelay(p->dist_pio_delay),
       cpuPioDelay(p->cpu_pio_delay), intLatency(p->int_latency),
-      enabled(false), itLines(p->it_lines), irqEnable(false),
-      msixRegAddr(p->msix_addr),
-      msixReg(0x0)
+      enabled(false), itLines(p->it_lines), irqEnable(false)
 {
     itLinesLog2 = ceilLog2(itLines);
 
@@ -113,10 +111,6 @@ Pl390::read(PacketPtr pkt)
         return readDistributor(pkt);
     else if (addr >= cpuAddr && addr < cpuAddr + CPU_SIZE)
         return readCpu(pkt);
-    else if (msixRegAddr != 0x0 &&
-             addr >= msixRegAddr &&
-             addr < msixRegAddr + MSIX_SIZE)
-        return readMsix(pkt);
     else
         panic("Read to unknown address %#x\n", pkt->getAddr());
 }
@@ -132,10 +126,6 @@ Pl390::write(PacketPtr pkt)
         return writeDistributor(pkt);
     else if (addr >= cpuAddr && addr < cpuAddr + CPU_SIZE)
         return writeCpu(pkt);
-    else if (msixRegAddr != 0x0 &&
-             addr >= msixRegAddr &&
-             addr < msixRegAddr + MSIX_SIZE)
-        return writeMsix(pkt);
     else
         panic("Write to unknown address %#x\n", pkt->getAddr());
 }
@@ -357,26 +347,6 @@ Pl390::readCpu(PacketPtr pkt)
     return cpuPioDelay;
 }
 
-Tick
-Pl390::readMsix(PacketPtr pkt)
-{
-    Addr daddr = pkt->getAddr() - msixRegAddr;
-
-    DPRINTF(GIC, "Gic MSIX read register %#x\n", daddr);
-
-    switch (daddr) {
-        case MSIX_SR:
-            pkt->set<uint32_t>(msixReg);
-            break;
-        default:
-            panic("Tried to read Gic MSIX register at offset %#x\n", daddr);
-            break;
-    }
-
-    pkt->makeAtomicResponse();
-    return distPioDelay;
-}
-
 Tick
 Pl390::writeDistributor(PacketPtr pkt)
 {
@@ -571,30 +541,6 @@ Pl390::writeCpu(PacketPtr pkt)
     return cpuPioDelay;
 }
 
-Tick
-Pl390::writeMsix(PacketPtr pkt)
-{
-    Addr daddr = pkt->getAddr() - msixRegAddr;
-
-    DPRINTF(GIC, "Gic MSI-X write register %#x data %d\n",
-                 daddr, pkt->get<uint32_t>());
-
-    switch (daddr) {
-        case MSIX_SR:
-            // This value is little endian, just like the ARM guest
-            msixReg = pkt->get<uint32_t>();
-            pendingInt[intNumToWord(letoh(msixReg))] |= 1UL << intNumToBit(letoh(msixReg));
-            updateIntState(-1);
-            break;
-        default:
-            panic("Tried to write Gic MSI-X register at offset %#x\n", daddr);
-            break;
-    }
-
-    pkt->makeAtomicResponse();
-    return distPioDelay;
-}
-
 void
 Pl390::softInt(int ctx_id, SWI swi)
 {
@@ -786,9 +732,6 @@ Pl390::getAddrRanges() const
     AddrRangeList ranges;
     ranges.push_back(RangeSize(distAddr, DIST_SIZE));
     ranges.push_back(RangeSize(cpuAddr, CPU_SIZE));
-    if (msixRegAddr != 0) {
-        ranges.push_back(RangeSize(msixRegAddr, MSIX_SIZE));
-    }
     return ranges;
 }
 
@@ -805,8 +748,6 @@ Pl390::serialize(std::ostream &os)
     SERIALIZE_SCALAR(enabled);
     SERIALIZE_SCALAR(itLines);
     SERIALIZE_SCALAR(itLinesLog2);
-    SERIALIZE_SCALAR(msixRegAddr);
-    SERIALIZE_SCALAR(msixReg);
     SERIALIZE_ARRAY(intEnabled, INT_BITS_MAX);
     SERIALIZE_ARRAY(pendingInt, INT_BITS_MAX);
     SERIALIZE_ARRAY(activeInt, INT_BITS_MAX);
@@ -847,8 +788,6 @@ Pl390::unserialize(Checkpoint *cp, const std::string &section)
     UNSERIALIZE_SCALAR(enabled);
     UNSERIALIZE_SCALAR(itLines);
     UNSERIALIZE_SCALAR(itLinesLog2);
-    UNSERIALIZE_SCALAR(msixRegAddr);
-    UNSERIALIZE_SCALAR(msixReg);
     UNSERIALIZE_ARRAY(intEnabled, INT_BITS_MAX);
     UNSERIALIZE_ARRAY(pendingInt, INT_BITS_MAX);
     UNSERIALIZE_ARRAY(activeInt, INT_BITS_MAX);

src/dev/arm/gic_pl390.hh

@@ -113,10 +113,6 @@ class Pl390 : public BaseGic
     static const int INT_BITS_MAX = 32;
     static const int INT_LINES_MAX = 1020;
 
-    /** MSI-X register offset and size */
-    static const int MSIX_SR = 0x0; // MSI register devices will write to
-    static const int MSIX_SIZE = 0x4; // Size of MSI-X register space
-
     BitUnion32(SWI)
         Bitfield<3,0> sgi_id;
         Bitfield<23,16> cpu_list;
@@ -211,10 +207,6 @@ class Pl390 : public BaseGic
     /** IRQ Enable Used for debug */
     bool irqEnable;
 
-    /** MSIX Register */
-    Addr msixRegAddr;
-    uint32_t msixReg;
-
     /** software generated interrupt
      * @param data data to decode that indicates which cpus to interrupt
      */
@@ -322,11 +314,6 @@ class Pl390 : public BaseGic
      */
     Tick readCpu(PacketPtr pkt);
 
-    /** Handle a read to the MSI-X register on the GIC
-     *  @param pkt packet to respond to
-     */
-    Tick readMsix(PacketPtr pkt);
-
     /** Handle a write to the distributor poriton of the GIC
      * @param pkt packet to respond to
      */
@@ -336,11 +323,6 @@ class Pl390 : public BaseGic
      * @param pkt packet to respond to
      */
     Tick writeCpu(PacketPtr pkt);
-
-    /** Handle a write to the MSI-X register on the GIC
-     *  @param pkt packet to process
-     */
-    Tick writeMsix(PacketPtr pkt);
 };
 
 #endif //__DEV_ARM_GIC_H__