From 52fa30b71d9f6a5ca904c8eee4513ac909ddfd6c Mon Sep 17 00:00:00 2001
From: joevt <joevt@shaw.ca>
Date: Mon, 12 Dec 2022 00:16:59 -0800
Subject: [PATCH] Add ability to unregister mmio region.

mmio regions are registered when a PCI BAR is set. Add the ability to reverse that - for when a PCI BAR is changed.
---
 devices/common/pci/pcihost.cpp  |  8 ++++++++
 devices/common/pci/pcihost.h    |  1 +
 devices/memctrl/memctrlbase.cpp | 22 ++++++++++++++++++++++
 devices/memctrl/memctrlbase.h   |  1 +
 4 files changed, 32 insertions(+)

diff --git a/devices/common/pci/pcihost.cpp b/devices/common/pci/pcihost.cpp
index 51dacf1..761a57a 100644
--- a/devices/common/pci/pcihost.cpp
+++ b/devices/common/pci/pcihost.cpp
@@ -53,6 +53,14 @@ bool PCIHost::pci_register_mmio_region(uint32_t start_addr, uint32_t size, PCIDe
     return mem_ctrl->add_mmio_region(start_addr, size, obj);
 }
 
+bool PCIHost::pci_unregister_mmio_region(uint32_t start_addr, uint32_t size, PCIDevice* obj)
+{
+    MemCtrlBase *mem_ctrl = dynamic_cast<MemCtrlBase *>
+                           (gMachineObj->get_comp_by_type(HWCompType::MEM_CTRL));
+    // FIXME: add sanity checks!
+    return mem_ctrl->remove_mmio_region(start_addr, size, obj);
+}
+
 void PCIHost::attach_pci_device(std::string& dev_name, int slot_id)
 {
     if (!DeviceRegistry::device_registered(dev_name)) {
diff --git a/devices/common/pci/pcihost.h b/devices/common/pci/pcihost.h
index d21c27e..5a0499a 100644
--- a/devices/common/pci/pcihost.h
+++ b/devices/common/pci/pcihost.h
@@ -42,6 +42,7 @@ public:
     virtual bool pci_register_device(int dev_num, PCIDevice* dev_instance);
 
     virtual bool pci_register_mmio_region(uint32_t start_addr, uint32_t size, PCIDevice* obj);
+    virtual bool pci_unregister_mmio_region(uint32_t start_addr, uint32_t size, PCIDevice* obj);
 
     virtual void attach_pci_device(std::string& dev_name, int slot_id);
 
diff --git a/devices/memctrl/memctrlbase.cpp b/devices/memctrl/memctrlbase.cpp
index 8632263..6e0c6d2 100644
--- a/devices/memctrl/memctrlbase.cpp
+++ b/devices/memctrl/memctrlbase.cpp
@@ -233,6 +233,28 @@ bool MemCtrlBase::add_mmio_region(uint32_t start_addr, uint32_t size, MMIODevice
     return true;
 }
 
+bool MemCtrlBase::remove_mmio_region(uint32_t start_addr, uint32_t size, MMIODevice* dev_instance) {
+    int found = 0;
+
+    uint32_t end = start_addr + size - 1;
+    address_map.erase(std::remove_if(address_map.begin(), address_map.end(),
+        [start_addr, end, dev_instance, &found](const AddressMapEntry *entry) {
+            bool result = (start_addr == entry->start && end == entry->end && (!dev_instance || dev_instance == entry->devobj));
+            found += result;
+            return result;
+        }
+    ), address_map.end());
+
+    if (found == 0)
+        LOG_F(ERROR, "Cannot find mmio region 0x%X..0x%X%s%s%s to remove", start_addr, end, dev_instance ? " (" : "", dev_instance ? dev_instance->get_name().c_str() : "", dev_instance ? ")" : "");
+    else if (found > 1)
+        LOG_F(ERROR, "Removed %d occurrences of mmio region 0x%X..0x%X%s%s%s", found, start_addr, end, dev_instance ? " (" : "", dev_instance ? dev_instance->get_name().c_str() : "", dev_instance ? ")" : "");
+    else
+        LOG_F(INFO, "Removed mmio region 0x%X..0x%X%s%s%s", start_addr, end, dev_instance ? " (" : "", dev_instance ? dev_instance->get_name().c_str() : "", dev_instance ? ")" : "");
+    
+    return (found > 0);
+}
+
 AddressMapEntry* MemCtrlBase::find_rom_region()
 {
     for (auto& entry : address_map) {
diff --git a/devices/memctrl/memctrlbase.h b/devices/memctrl/memctrlbase.h
index 484f79c..209bff1 100644
--- a/devices/memctrl/memctrlbase.h
+++ b/devices/memctrl/memctrlbase.h
@@ -68,6 +68,7 @@ public:
     virtual bool add_mem_mirror(uint32_t start_addr, uint32_t dest_addr);
 
     virtual bool add_mmio_region(uint32_t start_addr, uint32_t size, MMIODevice* dev_instance);
+    virtual bool remove_mmio_region(uint32_t start_addr, uint32_t size, MMIODevice* dev_instance);
 
     virtual bool set_data(uint32_t reg_addr, const uint8_t* data, uint32_t size);