From 2f725fe3e4c25bb085e8888fc35ffafaef7705ae Mon Sep 17 00:00:00 2001
From: Maxim Poliakovski <maximumspatium@googlemail.com>
Date: Thu, 14 Oct 2021 00:01:30 +0200
Subject: [PATCH] viacuda: fix PRAM reading and writing.

---
 devices/viacuda.cpp | 45 ++++++++++++++++++++++++++++++++-------------
 devices/viacuda.h   |  9 ++++++---
 2 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/devices/viacuda.cpp b/devices/viacuda.cpp
index bfc651e..f4df27d 100644
--- a/devices/viacuda.cpp
+++ b/devices/viacuda.cpp
@@ -24,10 +24,12 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
     Author: Max Poliakovski 2019
 */
 
-#include "viacuda.h"
 #include "adb.h"
+#include "memaccess.h"
+#include "viacuda.h"
 #include <cinttypes>
 #include <loguru.hpp>
+#include <memory>
 
 using namespace std;
 
@@ -43,19 +45,14 @@ ViaCuda::ViaCuda() {
     this->via_regs[VIA_T1LH] = 0xFF;
     this->via_regs[VIA_IER]  = 0x7F;
 
-    // PRAM Pre-Initialization
-    this->pram_obj = new NVram("pram.bin", 256);
+    // PRAM is part of Cuda
+    this->pram_obj = std::unique_ptr<NVram> (new NVram("pram.bin", 256));
 
     this->adb_obj = new ADB_Bus();
 
     this->init();
 }
 
-ViaCuda::~ViaCuda() {
-    if (this->pram_obj)
-        delete (this->pram_obj);
-}
-
 void ViaCuda::init() {
     this->old_tip     = 0;
     this->old_byteack = 0;
@@ -197,11 +194,17 @@ void ViaCuda::write(uint8_t new_state) {
     }
 }
 
-/* sends zeros to host at infinitum */
+/* sends zeros to host ad infinitum */
 void ViaCuda::null_out_handler() {
     this->via_regs[VIA_SR] = 0;
 }
 
+/* sends PRAM content to host ad infinitum */
+void ViaCuda::pram_out_handler()
+{
+    this->via_regs[VIA_SR] = this->pram_obj->read_byte(this->cur_pram_addr++);
+}
+
 /* sends data from out_buf until exhausted, then switches to next_out_handler */
 void ViaCuda::out_buf_handler() {
     if (this->out_pos < this->out_count) {
@@ -307,6 +310,8 @@ void ViaCuda::process_adb_command(uint8_t cmd_byte, int data_count) {
 }
 
 void ViaCuda::pseudo_command(int cmd, int data_count) {
+    uint16_t addr;
+
     switch (cmd) {
     case CUDA_START_STOP_AUTOPOLL:
         if (this->in_buf[2]) {
@@ -317,12 +322,26 @@ void ViaCuda::pseudo_command(int cmd, int data_count) {
         response_header(CUDA_PKT_PSEUDO, 0);
         break;
     case CUDA_READ_PRAM:
-        response_header(CUDA_PKT_PSEUDO, 0);
-        this->pram_obj->read_byte(this->in_buf[2]);
+        addr = READ_WORD_BE_A(&this->in_buf[2]);
+        if (addr <= 0xFF) {
+            response_header(CUDA_PKT_PSEUDO, 0);
+            // this command is open-ended so set up the corresponding context
+            this->cur_pram_addr    = addr;
+            this->next_out_handler = &ViaCuda::pram_out_handler;
+            this->is_open_ended    = true;
+        } else {
+            error_response(CUDA_ERR_BAD_PAR);
+        }
         break;
     case CUDA_WRITE_PRAM:
-        response_header(CUDA_PKT_PSEUDO, 0);
-        this->pram_obj->write_byte(this->in_buf[2], this->in_buf[3]);
+        addr = READ_WORD_BE_A(&this->in_buf[2]);
+        if (addr <= 0xFF) {
+            // TODO: implement open-ended write transaction properly
+            response_header(CUDA_PKT_PSEUDO, 0);
+            this->pram_obj->write_byte(addr, this->in_buf[4]);
+        } else {
+            error_response(CUDA_ERR_BAD_PAR);
+        }
         break;
     case CUDA_SET_AUTOPOLL_RATE:
         this->poll_rate = this->in_buf[2];
diff --git a/devices/viacuda.h b/devices/viacuda.h
index 0b7194c..00a0aea 100644
--- a/devices/viacuda.h
+++ b/devices/viacuda.h
@@ -49,6 +49,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include "hwcomponent.h"
 #include "i2c.h"
 #include "nvram.h"
+#include <memory>
 
 /** VIA register offsets. */
 enum {
@@ -103,6 +104,7 @@ enum {
     CUDA_ERR_BAD_PKT  = 1, /* invalid packet type */
     CUDA_ERR_BAD_CMD  = 2, /* invalid pseudo command */
     CUDA_ERR_BAD_SIZE = 3, /* invalid packet size */
+    CUDA_ERR_BAD_PAR  = 4, /* invalid parameter */
     CUDA_ERR_I2C      = 5  /* invalid I2C data or no acknowledge */
 };
 
@@ -110,7 +112,7 @@ enum {
 class ViaCuda : public HWComponent, public I2CBus {
 public:
     ViaCuda();
-    ~ViaCuda();
+    ~ViaCuda() = default;
 
     bool supports_type(HWCompType type) {
         return (type == HWCompType::ADB_HOST || type == HWCompType::I2C_HOST);
@@ -135,11 +137,12 @@ private:
 
     bool is_open_ended;
     uint8_t curr_i2c_addr;
+    uint8_t cur_pram_addr;
 
     void (ViaCuda::*out_handler)(void);
     void (ViaCuda::*next_out_handler)(void);
 
-    NVram* pram_obj;
+    std::unique_ptr<NVram>  pram_obj;
     ADB_Bus* adb_obj;
 
     void print_enabled_ints(); /* print enabled VIA interrupts and their sources */
@@ -149,13 +152,13 @@ private:
     void assert_sr_int();
     void write(uint8_t new_state);
     void response_header(uint32_t pkt_type, uint32_t pkt_flag);
-    // void cuda_response_packet();
     void error_response(uint32_t error);
     void process_packet();
     void process_adb_command(uint8_t cmd_byte, int data_count);
     void pseudo_command(int cmd, int data_count);
 
     void null_out_handler(void);
+    void pram_out_handler(void);
     void out_buf_handler(void);
     void i2c_handler(void);