Working AHCI DMA IPC from yellowstone to denali.

We have a weird bug in context switching where a process's rsp0 ends up
pointing at the wrong value sometimes which crashes the OS.

sys/denali/ahci/ahci.h

@@ -96,7 +96,7 @@ struct CommandTable {
   uint8_t command_fis[64];
   uint8_t atapi_command[16];
   uint8_t reserved[48];
-  PhysicalRegionDescriptor prds[65535];
+  PhysicalRegionDescriptor prdt[65535];
 } __attribute__((packed));
 
 typedef enum {

sys/denali/ahci/ahci_device.cpp

@@ -4,12 +4,6 @@
 #include <string.h>
 #include <zcall.h>
 
-namespace {
-
-void HandleIdent(AhciDevice* dev) { dev->HandleIdentify(); }
-
-}  // namespace
-
 AhciDevice::AhciDevice(AhciPort* port) : port_struct_(port) {
   if ((port_struct_->sata_status & 0x103) != 0x103) {
     return;
@@ -38,59 +32,25 @@ AhciDevice::AhciDevice(AhciPort* port) : port_struct_(port) {
       reinterpret_cast<CommandTable*>(command_structures_.vaddr() + ct_off);
 
   port_struct_->interrupt_enable = 0xFFFFFFFF;
-
-  if (port_struct_->signature == 0x101) {
-    SendIdentify();
-  }
 }
 
-z_err_t AhciDevice::SendIdentify() {
-  HostToDeviceRegisterFis fis{
-      .fis_type = FIS_TYPE_REG_H2D,
-      .pmp_and_c = 0x80,
-      .command = 0xEC,
-      .featurel = 0,
+z_err_t AhciDevice::IssueCommand(Command* command) {
+  command->PopulateFis(command_table_->command_fis);
+  command->PopulatePrdt(command_table_->prdt);
 
-      .lba0 = 0,
-      .lba1 = 0,
-      .lba2 = 0,
-      .device = 0,
-
-      .lba3 = 0,
-      .lba4 = 0,
-      .lba5 = 0,
-      .featureh = 0,
-
-      .count = 0,
-      .icc = 0,
-      .control = 0,
-
-      .reserved = 0,
-  };
-
-  command_list_->command_headers[0].command = (sizeof(fis) / 2) & 0x1F;
+  command_list_->command_headers[0].command =
+      (sizeof(HostToDeviceRegisterFis) / 2) & 0x1F;
   command_list_->command_headers[0].prd_table_length = 1;
+  command_list_->command_headers[0].prd_byte_count = 0;
 
-  memcpy(command_table_->command_fis, &fis, sizeof(fis));
+  commands_[0] = command;
 
-  commands_[0].region = MappedMemoryRegion::ContiguousPhysical(512);
-  //  commands_[0].callback = HandleIdent;
-
-  command_table_->prds[0].region_address = commands_[0].region.paddr();
-  command_table_->prds[0].byte_count = 512;
-
-  port_struct_->command_issue |= 1;
   commands_issued_ |= 1;
+  port_struct_->command_issue |= 1;
 
   return Z_OK;
 }
 
-void AhciDevice::HandleIdentify() {
-  dbgln("Handling Idenify");
-  uint16_t* ident = reinterpret_cast<uint16_t*>(commands_[0].region.vaddr());
-  dbgln("Ident: %x", ident[0]);
-}
-
 void AhciDevice::DumpInfo() {
   dbgln("Comlist: %lx", port_struct_->command_list_base);
   dbgln("FIS: %lx", port_struct_->fis_base);
@@ -116,11 +76,15 @@ void AhciDevice::HandleIrq() {
   port_struct_->interrupt_status = int_status;
 
   uint32_t commands_finished = commands_issued_ & ~port_struct_->command_issue;
+  dbgln("finished %x", commands_finished);
+  dbgln("status %x", int_status);
+  dbgln("Issued %x, %x", commands_issued_, port_struct_->command_issue);
 
+  // FIXME: Pass error codes to the callback.
   for (uint64_t i = 0; i < 32; i++) {
     if (commands_finished & (1 << i)) {
-      // commands_[i].callback(this);
       commands_issued_ &= ~(1 << i);
+      commands_[i]->Callback();
     }
   }
 
@@ -134,6 +98,7 @@ void AhciDevice::HandleIrq() {
     }
     if (fis.error) {
       dbgln("D2H err: %x", fis.error);
+      dbgln("status: %x", fis.status);
     }
   }
   if (int_status & 0x2) {

sys/denali/ahci/ahci_device.h

@@ -4,6 +4,7 @@
 #include <zerrors.h>
 
 #include "ahci/ahci.h"
+#include "ahci/command.h"
 
 class AhciDevice {
  public:
@@ -15,11 +16,13 @@ class AhciDevice {
 
   bool IsInit() { return port_struct_ != nullptr && command_structures_; }
 
-  z_err_t SendIdentify();
-  void HandleIdentify();
+  z_err_t IssueCommand(Command* command);
 
   void HandleIrq();
 
+  AhciDevice(const AhciDevice&) = delete;
+  AhciDevice& operator=(const AhciDevice&) = delete;
+
  private:
   AhciPort* port_struct_ = nullptr;
   MappedMemoryRegion command_structures_;
@@ -28,10 +31,6 @@ class AhciDevice {
   ReceivedFis* received_fis_ = nullptr;
   CommandTable* command_table_ = nullptr;
 
-  struct Command {
-    MappedMemoryRegion region;
-    // std::function<void(MappedMemoryRegion)> callback;
-  };
-  Command commands_[32];
-  uint32_t commands_issued_ = 0;
+  Command* commands_[32];
+  volatile uint32_t commands_issued_ = 0;
 };

sys/denali/ahci/ahci_driver.cpp

@@ -33,16 +33,16 @@ z_err_t AhciDriver::Init() {
   return Z_OK;
 }
 
-z_err_t AhciDriver::GetDevice(uint64_t id, AhciDevice& device) {
+z_err_t AhciDriver::GetDevice(uint64_t id, AhciDevice** device) {
   if (id >= 32) {
     return Z_ERR_INVALID;
   }
 
-  if (!devices_[id].IsInit()) {
+  if (devices_[id] != nullptr && !devices_[id]->IsInit()) {
     return Z_ERR_NOT_FOUND;
   }
 
-  device = devices_[id];
+  *device = devices_[id];
   return Z_OK;
 }
 
@@ -126,24 +126,27 @@ void AhciDriver::DumpCapabilities() {
 
 void AhciDriver::DumpPorts() {
   for (uint64_t i = 0; i < 6; i++) {
-    AhciDevice& dev = devices_[i];
-    if (!dev.IsInit()) {
+    AhciDevice* dev = devices_[i];
+    if (dev == nullptr || !dev->IsInit()) {
       continue;
     }
 
     dbgln("");
     dbgln("Port %u:", i);
-    dev.DumpInfo();
+    dev->DumpInfo();
   }
 }
 
 void AhciDriver::InterruptLoop() {
+  dbgln("Starting interrupt loop");
   while (true) {
     uint64_t type, bytes, caps;
     check(ZPortRecv(irq_port_cap_, 0, 0, 0, 0, &type, &bytes, &caps));
     for (uint64_t i = 0; i < 32; i++) {
-      if (devices_[i].IsInit() && (ahci_hba_->interrupt_status & (1 << i))) {
-        devices_[i].HandleIrq();
+      if (devices_[i] != nullptr && devices_[i]->IsInit() &&
+          (ahci_hba_->interrupt_status & (1 << i))) {
+        dbgln("Interrupt for %u", i);
+        devices_[i]->HandleIrq();
         ahci_hba_->interrupt_status &= ~(1 << i);
       }
     }
@@ -212,7 +215,7 @@ z_err_t AhciDriver::LoadDevices() {
     }
     uint64_t port_addr =
         reinterpret_cast<uint64_t>(ahci_hba_) + 0x100 + (0x80 * i);
-    devices_[i] = AhciDevice(reinterpret_cast<AhciPort*>(port_addr));
+    devices_[i] = new AhciDevice(reinterpret_cast<AhciPort*>(port_addr));
   }
   return Z_OK;
 }

sys/denali/ahci/ahci_driver.h

@@ -12,7 +12,7 @@ class AhciDriver {
 
   void InterruptLoop();
 
-  z_err_t GetDevice(uint64_t id, AhciDevice& device);
+  z_err_t GetDevice(uint64_t id, AhciDevice** device);
 
   void DumpCapabilities();
   void DumpPorts();
@@ -24,7 +24,7 @@ class AhciDriver {
   AhciHba* ahci_hba_ = nullptr;
 
   // TODO: Allocate these dynamically.
-  AhciDevice devices_[32];
+  AhciDevice* devices_[32];
 
   Thread irq_thread_;
   uint64_t irq_port_cap_ = 0;

sys/denali/ahci/command.cpp

@@ -0,0 +1,49 @@
+#include "ahci/command.h"
+
+#include <string.h>
+
+#include "ahci/ahci.h"
+
+Command::~Command() {}
+
+DmaReadCommand::DmaReadCommand(uint64_t lba, uint64_t sector_cnt,
+                               DmaCallback callback)
+    : lba_(lba), sector_cnt_(sector_cnt), callback_(callback) {
+  region_ = MappedMemoryRegion::ContiguousPhysical(sector_cnt * 512);
+}
+
+DmaReadCommand::~DmaReadCommand() {}
+
+void DmaReadCommand::PopulateFis(uint8_t* command_fis) {
+  HostToDeviceRegisterFis fis{
+      .fis_type = FIS_TYPE_REG_H2D,
+      .pmp_and_c = 0x80,
+      .command = 0x25,
+      .featurel = 0,
+
+      .lba0 = static_cast<uint8_t>(lba_ & 0xFF),
+      .lba1 = static_cast<uint8_t>((lba_ >> 8) & 0xFF),
+      .lba2 = static_cast<uint8_t>((lba_ >> 16) & 0xFF),
+      .device = (1 << 6),  // ATA LBA Mode
+
+      .lba3 = static_cast<uint8_t>((lba_ >> 24) & 0xFF),
+      .lba4 = static_cast<uint8_t>((lba_ >> 32) & 0xFF),
+      .lba5 = static_cast<uint8_t>((lba_ >> 40) & 0xFF),
+      .featureh = 0,
+
+      .count = static_cast<uint16_t>(sector_cnt_),
+      .icc = 0,
+      .control = 0,
+
+      .reserved = 0,
+  };
+
+  uint64_t bytes = sector_cnt_ * 512;
+
+  memcpy(command_fis, &fis, sizeof(fis));
+}
+void DmaReadCommand::PopulatePrdt(PhysicalRegionDescriptor* prdt) {
+  prdt[0].region_address = region_.paddr();
+  prdt[0].byte_count = region_.size();
+}
+void DmaReadCommand::Callback() { callback_(lba_, sector_cnt_, region_.cap()); }

sys/denali/ahci/command.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <mammoth/memory_region.h>
+#include <stdint.h>
+
+#include "ahci/ahci.h"
+
+class Command {
+ public:
+  virtual ~Command();
+  virtual void PopulateFis(uint8_t* command_fis) = 0;
+  virtual void PopulatePrdt(PhysicalRegionDescriptor* prdt) = 0;
+  virtual void Callback() = 0;
+};
+
+class DmaReadCommand : public Command {
+ public:
+  typedef void (*DmaCallback)(uint64_t, uint64_t, uint64_t);
+  DmaReadCommand(uint64_t lba, uint64_t sector_cnt, DmaCallback callback);
+
+  virtual ~DmaReadCommand() override;
+
+  void PopulateFis(uint8_t* command_fis) override;
+  void PopulatePrdt(PhysicalRegionDescriptor* prdt) override;
+
+  void Callback() override;
+
+ private:
+  uint64_t lba_;
+  uint64_t sector_cnt_;
+  DmaCallback callback_;
+  MappedMemoryRegion region_;
+};