From acfaf2639120124a9b2bcf1a4598ff8cd50d3053 Mon Sep 17 00:00:00 2001
From: Drew Galbraith <dgalbraith33@gmail.com>
Date: Wed, 25 Oct 2023 19:39:09 -0700
Subject: [PATCH] [Denali] Use mutexes to synchronize the AHCI responses.

This is a temporary solution to allow denali to migrate to the
yunq framework until we have a good async solution.
---
 sys/denali/ahci/command.cpp  |  8 +++-----
 sys/denali/ahci/command.h    |  8 +++++---
 sys/denali/denali_server.cpp | 31 ++++++++++++-------------------
 sys/denali/denali_server.h   |  3 ---
 4 files changed, 20 insertions(+), 30 deletions(-)

diff --git a/sys/denali/ahci/command.cpp b/sys/denali/ahci/command.cpp
index 986ca6d..c79a068 100644
--- a/sys/denali/ahci/command.cpp
+++ b/sys/denali/ahci/command.cpp
@@ -7,11 +7,11 @@
 Command::~Command() {}
 
 DmaReadCommand::DmaReadCommand(uint64_t lba, uint64_t sector_cnt,
-                               DmaCallback callback, ResponseContext& response)
+                               Mutex& callback_mutex, ResponseContext& response)
     : response_(response),
       lba_(lba),
       sector_cnt_(sector_cnt),
-      callback_(callback) {
+      callback_mutex_(callback_mutex) {
   region_ = MappedMemoryRegion::ContiguousPhysical(sector_cnt * 512);
 }
 
@@ -49,6 +49,4 @@ void DmaReadCommand::PopulatePrdt(PhysicalRegionDescriptor* prdt) {
   prdt[0].region_address = region_.paddr();
   prdt[0].byte_count = region_.size();
 }
-void DmaReadCommand::Callback() {
-  callback_(response_, lba_, sector_cnt_, region_.cap());
-}
+void DmaReadCommand::Callback() { callback_mutex_.Release(); }
diff --git a/sys/denali/ahci/command.h b/sys/denali/ahci/command.h
index 9870685..5464369 100644
--- a/sys/denali/ahci/command.h
+++ b/sys/denali/ahci/command.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <mammoth/memory_region.h>
+#include <mammoth/mutex.h>
 #include <mammoth/response_context.h>
 #include <stdint.h>
 
@@ -16,8 +17,7 @@ class Command {
 
 class DmaReadCommand : public Command {
  public:
-  typedef void (*DmaCallback)(ResponseContext&, uint64_t, uint64_t, z_cap_t);
-  DmaReadCommand(uint64_t lba, uint64_t sector_cnt, DmaCallback callback,
+  DmaReadCommand(uint64_t lba, uint64_t sector_cnt, Mutex& callback_mutex_,
                  ResponseContext& reply_port);
 
   virtual ~DmaReadCommand() override;
@@ -27,10 +27,12 @@ class DmaReadCommand : public Command {
 
   void Callback() override;
 
+  z_cap_t GetMemoryRegion() { return region_.cap(); }
+
  private:
   ResponseContext& response_;
   uint64_t lba_;
   uint64_t sector_cnt_;
-  DmaCallback callback_;
+  Mutex& callback_mutex_;
   MappedMemoryRegion region_;
 };
diff --git a/sys/denali/denali_server.cpp b/sys/denali/denali_server.cpp
index caa29a4..a4e9767 100644
--- a/sys/denali/denali_server.cpp
+++ b/sys/denali/denali_server.cpp
@@ -5,14 +5,6 @@
 #include <mammoth/debug.h>
 #include <zcall.h>
 
-namespace {
-DenaliServer* gServer = nullptr;
-void HandleResponse(ResponseContext& response, uint64_t lba, uint64_t size,
-                    z_cap_t mem) {
-  gServer->HandleResponse(response, lba, size, mem);
-}
-}  // namespace
-
 glcr::ErrorOr<glcr::UniquePtr<DenaliServer>> DenaliServer::Create(
     AhciDriver& driver) {
   z_cap_t cap;
@@ -45,19 +37,20 @@ glcr::ErrorCode DenaliServer::HandleRequest(RequestContext& request,
 glcr::ErrorCode DenaliServer::HandleRead(DenaliReadRequest* request,
                                          ResponseContext& context) {
   ASSIGN_OR_RETURN(AhciDevice * device, driver_.GetDevice(request->device_id));
+  ASSIGN_OR_RETURN(Mutex mutex, Mutex::Create());
+  RET_ERR(mutex.Lock());
 
-  device->IssueCommand(new DmaReadCommand(request->lba, request->size,
-                                          ::HandleResponse, context));
+  DmaReadCommand command(request->lba, request->size, mutex, context);
+  device->IssueCommand(&command);
 
-  return glcr::OK;
-}
-
-void DenaliServer::HandleResponse(ResponseContext& response, uint64_t lba,
-                                  uint64_t size, z_cap_t mem) {
+  // Wait for read operation to complete.
+  RET_ERR(mutex.Lock());
+  RET_ERR(mutex.Release());
   DenaliReadResponse resp{
-      .device_id = 0,
-      .lba = lba,
-      .size = size,
+      .device_id = request->device_id,
+      .lba = request->lba,
+      .size = request->size,
   };
-  check(response.WriteStructWithCap<DenaliReadResponse>(resp, mem));
+  return context.WriteStructWithCap<DenaliReadResponse>(
+      resp, command.GetMemoryRegion());
 }
diff --git a/sys/denali/denali_server.h b/sys/denali/denali_server.h
index 677185d..82c6a85 100644
--- a/sys/denali/denali_server.h
+++ b/sys/denali/denali_server.h
@@ -11,9 +11,6 @@ class DenaliServer : public EndpointServer {
   static glcr::ErrorOr<glcr::UniquePtr<DenaliServer>> Create(
       AhciDriver& driver);
 
-  void HandleResponse(ResponseContext& response, uint64_t lba, uint64_t size,
-                      z_cap_t cap);
-
   virtual glcr::ErrorCode HandleRequest(RequestContext& request,
                                         ResponseContext& response) override;