1 files changed, 149 insertions, 0 deletions
diff --git a/src/drivers/storage.cpp b/src/drivers/storage.cpp
new file mode 100644
index 00000000..7fed6ed0
--- /dev/null
+++ b/src/drivers/storage.cpp
@@ -0,0 +1,149 @@
+#include "storage.hpp"
+
+#include "gpio-expander.hpp"
+
+#include <atomic>
+#include <memory>
+#include <mutex>
+
+#include "diskio_impl.h"
+#include "diskio_sdmmc.h"
+#include "driver/gpio.h"
+#include "driver/sdmmc_types.h"
+#include "driver/sdspi_host.h"
+#include "esp_check.h"
+#include "esp_err.h"
+#include "esp_vfs_fat.h"
+#include "ff.h"
+#include "hal/gpio_types.h"
+#include "hal/spi_types.h"
+#include "sdmmc_cmd.h"
+
+static const char* kTag = "SDSTORAGE";
+static const uint8_t kMaxOpenFiles = 8;
+
+namespace gay_ipod {
+
+const char* kStoragePath = "/sdcard";
+
+// Static functions for interrop with the ESP IDF API, which requires a
+// function pointer.
+namespace callback {
+static std::atomic<SdStorage*> instance = nullptr;
+static std::atomic<esp_err_t (*)(sdspi_dev_handle_t, sdmmc_command_t*)>
+    bootstrap = nullptr;
+
+static esp_err_t do_transaction(sdspi_dev_handle_t handle,
+                                sdmmc_command_t* cmdinfo) {
+  auto bootstrap_fn = bootstrap.load();
+  if (bootstrap_fn != nullptr) {
+    return bootstrap_fn(handle, cmdinfo);
+  }
+  auto instance_unwrapped = instance.load();
+  if (instance_unwrapped == nullptr) {
+    ESP_LOGW(kTag, "uncaught sdspi transaction");
+    return ESP_OK;
+  }
+  // TODO: what if a transaction comes in right now?
+  return instance_unwrapped->HandleTransaction(handle, cmdinfo);
+}
+}  // namespace callback
+
+auto SdStorage::create(GpioExpander* gpio)
+    -> cpp::result<std::unique_ptr<SdStorage>, Error> {
+  // Acquiring the bus will also flush the mux switch change.
+  gpio->set_pin(GpioExpander::SD_MUX_SWITCH, GpioExpander::SD_MUX_ESP);
+
+  sdspi_dev_handle_t handle;
+  std::unique_ptr<sdmmc_host_t> host;
+  std::unique_ptr<sdmmc_card_t> card;
+  FATFS* fs = nullptr;
+
+  // Now we can init the driver and set up the SD card into SPI mode.
+  sdspi_host_init();
+
+  sdspi_device_config_t config = {
+      .host_id = VSPI_HOST,
+      // CS handled manually bc it's on the GPIO expander
+      .gpio_cs = GPIO_NUM_2,
+      .gpio_cd = SDSPI_SLOT_NO_CD,
+      .gpio_wp = SDSPI_SLOT_NO_WP,
+      .gpio_int = GPIO_NUM_NC,
+  };
+  if (esp_err_t err = sdspi_host_init_device(&config, &handle) != ESP_OK) {
+    ESP_LOGE(kTag, "Failed to init, err %d", err);
+    return cpp::fail(Error::FAILED_TO_INIT);
+  }
+
+  host = std::make_unique<sdmmc_host_t>(sdmmc_host_t SDSPI_HOST_DEFAULT());
+  card = std::make_unique<sdmmc_card_t>();
+
+  // We manage the CS pin ourselves via the GPIO expander. To do this safely in
+  // a multithreaded environment, we wrap the ESP IDF do_transaction function
+  // with our own that acquires the CS mutex for the duration of the SPI
+  // transaction.
+  auto do_transaction = host->do_transaction;
+  host->do_transaction = &callback::do_transaction;
+  host->slot = handle;
+  callback::bootstrap = do_transaction;
+
+  auto lock = gpio->AcquireSpiBus(GpioExpander::SD_CARD);
+  // Will return ESP_ERR_INVALID_RESPONSE if there is no card
+  esp_err_t err = sdmmc_card_init(host.get(), card.get());
+  if (err != ESP_OK) {
+    ESP_LOGW(kTag, "Failed to read, err: %d", err);
+    return cpp::fail(Error::FAILED_TO_READ);
+  }
+
+  ESP_ERROR_CHECK(esp_vfs_fat_register(kStoragePath, "", kMaxOpenFiles, &fs));
+  ff_diskio_register_sdmmc(fs->pdrv, card.get());
+
+  // Mount right now, not on first operation.
+  FRESULT ferr = f_mount(fs, "", 1);
+  if (ferr != FR_OK) {
+    ESP_LOGW(kTag, "Failed to mount, err: %d", ferr);
+    return cpp::fail(Error::FAILED_TO_MOUNT);
+  }
+
+  return std::make_unique<SdStorage>(gpio, do_transaction, handle, host, card,
+                                     fs);
+}
+
+SdStorage::SdStorage(GpioExpander* gpio,
+                     esp_err_t (*do_transaction)(sdspi_dev_handle_t,
+                                                 sdmmc_command_t*),
+                     sdspi_dev_handle_t handle,
+                     std::unique_ptr<sdmmc_host_t>& host,
+                     std::unique_ptr<sdmmc_card_t>& card,
+                     FATFS* fs)
+    : gpio_(gpio),
+      do_transaction_(do_transaction),
+      handle_(handle),
+      host_(std::move(host)),
+      card_(std::move(card)),
+      fs_(fs) {
+  callback::instance = this;
+  callback::bootstrap = nullptr;
+}
+
+SdStorage::~SdStorage() {
+  // Unmount and unregister the filesystem
+  f_unmount("");
+  ff_diskio_register(fs_->pdrv, NULL);
+  esp_vfs_fat_unregister_path(kStoragePath);
+  fs_ = nullptr;
+
+  callback::instance = nullptr;
+
+  // Uninstall the SPI driver
+  sdspi_host_remove_device(this->handle_);
+  sdspi_host_deinit();
+}
+
+auto SdStorage::HandleTransaction(sdspi_dev_handle_t handle,
+                                  sdmmc_command_t* cmdinfo) -> esp_err_t {
+  auto lock = gpio_->AcquireSpiBus(GpioExpander::SD_CARD);
+  return do_transaction_(handle, cmdinfo);
+}
+
+}  // namespace gay_ipod