From 198b918a3c8f6422ad304f43ba5dbc8bb3b742b5 Mon Sep 17 00:00:00 2001
From: Maxim Poliakovski <maximumspatium@googlemail.com>
Date: Mon, 7 Oct 2019 03:21:01 +0200
Subject: [PATCH] MPC106: allocate RAM after software setup.

Software will setup MPC106 internal registers and
finally set MCCR1[MEMGO] flag. This is the right time
for initializing physical RAM.
---
 devices/mmiodevice.h |  1 +
 devices/mpc106.cpp   | 42 ++++++++++++++++++++++++++++++++++++++++++
 devices/mpc106.h     |  2 ++
 main.cpp             |  3 +--
 4 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/devices/mmiodevice.h b/devices/mmiodevice.h
index 454d1af..adc6140 100644
--- a/devices/mmiodevice.h
+++ b/devices/mmiodevice.h
@@ -6,6 +6,7 @@
 
 #define READ_WORD_BE(addr)  ((addr)[0] << 16) | (addr)[1]
 #define READ_DWORD_BE(addr) ((addr)[0] << 24) | ((addr)[1] << 16) | ((addr)[2] << 8) | (addr)[3]
+#define READ_DWORD_LE(addr) ((addr)[3] << 24) | ((addr)[2] << 16) | ((addr)[1] << 8) | (addr)[0]
 
 /** Abstract class representing a simple, memory-mapped I/O device */
 class MMIODevice {
diff --git a/devices/mpc106.cpp b/devices/mpc106.cpp
index 7c90630..2527b06 100644
--- a/devices/mpc106.cpp
+++ b/devices/mpc106.cpp
@@ -160,6 +160,13 @@ void MPC106::pci_cfg_write(uint32_t reg_offs, uint32_t value, uint32_t size)
         std::cout << "MPC106 read error: invalid size parameter " << size
             << std::endl;
     }
+
+    if (this->my_pci_cfg_hdr[0xF2] & 8) {
+#ifdef MPC106_DEBUG
+        std::cout << "MPC106: MCCR1[MEMGO] was set! " << std::endl;
+#endif
+        setup_ram();
+    }
 }
 
 bool MPC106::pci_register_device(int dev_num, PCIDevice *dev_instance)
@@ -179,3 +186,38 @@ bool MPC106::pci_register_mmio_region(uint32_t start_addr, uint32_t size, PCIDev
     // FIXME: add sanity checks!
     return this->add_mmio_region(start_addr, size, obj);
 }
+
+void MPC106::setup_ram()
+{
+    uint32_t mem_start, mem_end, ext_mem_start, ext_mem_end, bank_start, bank_end;
+    uint32_t ram_size = 0;
+
+    uint8_t  bank_en = this->my_pci_cfg_hdr[0xA0];
+
+    for (int bank = 0; bank < 8; bank++) {
+        if (bank_en & (1 << bank)) {
+            if (bank < 4) {
+                mem_start = READ_DWORD_LE(&this->my_pci_cfg_hdr[0x80]);
+                ext_mem_start = READ_DWORD_LE(&this->my_pci_cfg_hdr[0x88]);
+                mem_end = READ_DWORD_LE(&this->my_pci_cfg_hdr[0x90]);
+                ext_mem_end = READ_DWORD_LE(&this->my_pci_cfg_hdr[0x98]);
+            } else {
+                mem_start = READ_DWORD_LE(&this->my_pci_cfg_hdr[0x84]);
+                ext_mem_start = READ_DWORD_LE(&this->my_pci_cfg_hdr[0x8C]);
+                mem_end = READ_DWORD_LE(&this->my_pci_cfg_hdr[0x94]);
+                ext_mem_end = READ_DWORD_LE(&this->my_pci_cfg_hdr[0x9C]);
+            }
+            bank_start = (((ext_mem_start >> bank * 8) & 3) << 30) |
+                (((mem_start >> bank * 8) & 0xFF) << 20);
+            bank_end = (((ext_mem_end >> bank * 8) & 3) << 30) |
+                (((mem_end >> bank * 8) & 0xFF) << 20) | 0xFFFFFUL;
+            if (bank && bank_start != ram_size)
+                std::cout << "MPC106 error: RAM not contiguous!" << std::endl;
+            ram_size += bank_end + 1;
+        }
+    }
+
+    if (!this->add_ram_region(0, ram_size)) {
+        std::cout << "MPC106 RAM allocation failed!" << std::endl;
+    }
+}
diff --git a/devices/mpc106.h b/devices/mpc106.h
index c5ddb8f..8166dd7 100644
--- a/devices/mpc106.h
+++ b/devices/mpc106.h
@@ -58,6 +58,8 @@ protected:
     //bool pci_register_device(int dev_num, PCIDevice *dev_instance);
     bool pci_register_mmio_region(uint32_t start_addr, uint32_t size, PCIDevice *obj);
 
+    void setup_ram(void);
+
 private:
     uint8_t my_pci_cfg_hdr[256] = {
         0x57, 0x10, // vendor ID: Motorola
diff --git a/main.cpp b/main.cpp
index c5fe13a..6f3af38 100644
--- a/main.cpp
+++ b/main.cpp
@@ -551,8 +551,7 @@ int main(int argc, char **argv)
             cout << "Initialize Gossamer hardware...";
             MPC106 *mpc106 = new MPC106();
             mem_ctrl_instance = mpc106;
-            if (!mem_ctrl_instance->add_rom_region(0xFFC00000, 0x400000) ||
-                !mem_ctrl_instance->add_ram_region(0x00000000, 0x800000)) {
+            if (!mem_ctrl_instance->add_rom_region(0xFFC00000, 0x400000)) {
                 cout << "failure!\n" << endl;
                 delete(mem_ctrl_instance);
                 romFile.close();