adamksmith
a911b9e4cb
ESPHome external_component that presents a synthetic 64 KB FAT12 disk over the ESP32-S3's native USB-OTG, containing a one-byte switch_position file and a switch_position_grub.cfg snippet. The disk's volume serial is fixed at 0x55AA6922 to stay drop-in compatible with the upstream /etc/grub.d hook. Components: - fat12 / msc_disk: portable FAT12 sector synthesiser ported from reference/src/fat.c and the boot-sector / FAT / dir-entry generation in reference/src/usb.c. - usb_descriptors / tusb_glue: TinyUSB MSC class with our own callbacks delegating to MscDisk::read_lba (linker --allow-multiple-definition picks ours over esp_tinyusb's storage-backed defaults). - grub_boot_switch: top-level Component, NVS persistence on target changes, exposes targets table to sub-platforms. - select: HA-facing select platform reading parent's targets map. Validated end-to-end on an ESP32-S3-DevKitC-1: USB enumerates as 26ba:8003, /dev/sdb mounts FAT12, mtype reads back the live target, and POST /select/boot_target/set?option=Windows updates both files on the next host read.
117 lines
3.7 KiB
C++
117 lines
3.7 KiB
C++
#include "grub_boot_switch.h"
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#include "usb_descriptors.h"
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#include "tinyusb.h"
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namespace esphome {
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namespace grub_boot_switch {
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static const char *const TAG = "grub_boot_switch";
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extern GrubBootSwitch *g_active_component; // defined in tusb_glue.cpp
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static UsbDescriptorBundle s_usb_descriptors;
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std::string GrubBootSwitch::label_for_digit(uint8_t digit) const {
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for (const auto &t : targets_) {
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if (t.first == digit)
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return t.second;
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}
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return std::string();
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}
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bool GrubBootSwitch::digit_for_label(const std::string &label, uint8_t *out) const {
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for (const auto &t : targets_) {
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if (t.second == label) {
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if (out)
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*out = t.first;
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return true;
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}
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}
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return false;
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}
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void GrubBootSwitch::set_target(uint8_t t) {
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if (current_target_.load() == t)
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return;
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current_target_.store(t);
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pref_.save(&t);
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for (auto &cb : callbacks_)
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cb(t);
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}
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void GrubBootSwitch::install_virtual_files_() {
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// File 1: bare ASCII digit, one byte. Mirrors readSwitch() in the reference.
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disk_.add_file("switch_position", "SWITCH~1", " ", 1,
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[this](uint8_t *out) { out[0] = '0' + (current_target_.load() % 10); });
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// File 2: GRUB snippet. Length and final-byte position match the reference's
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// grubConfigStr ("set os_hw_switch=N\n") so existing /etc/grub.d hooks parse
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// it identically.
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static const char kPrefix[] = "set os_hw_switch=";
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static const size_t kPrefixLen = sizeof(kPrefix) - 1;
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static const size_t kFileLen = kPrefixLen + 2; // digit + newline
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disk_.add_file("switch_position_grub.cfg", "SWITCH~1", "CFG", kFileLen,
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[this](uint8_t *out) {
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memcpy(out, kPrefix, kPrefixLen);
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out[kPrefixLen] = '0' + (current_target_.load() % 10);
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out[kPrefixLen + 1] = '\n';
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});
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}
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void GrubBootSwitch::start_usb_() {
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g_active_component = this;
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usb_descriptors_build(&s_usb_descriptors, usb_vid_, usb_pid_,
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usb_manufacturer_.c_str(), usb_product_.c_str(), nullptr);
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tinyusb_config_t cfg = {};
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cfg.device_descriptor =
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reinterpret_cast<const tusb_desc_device_t *>(s_usb_descriptors.device);
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cfg.string_descriptor = s_usb_descriptors.strings;
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cfg.string_descriptor_count =
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sizeof(s_usb_descriptors.strings) / sizeof(s_usb_descriptors.strings[0]);
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cfg.external_phy = false;
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cfg.configuration_descriptor = s_usb_descriptors.config;
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cfg.self_powered = false;
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esp_err_t err = tinyusb_driver_install(&cfg);
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if (err != ESP_OK) {
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ESP_LOGE(TAG, "tinyusb_driver_install failed: %d", err);
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this->mark_failed();
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return;
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}
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ESP_LOGI(TAG, "TinyUSB MSC installed (VID=%04X PID=%04X serial=%s)", usb_vid_,
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usb_pid_, s_usb_descriptors.serial_buf);
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}
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void GrubBootSwitch::setup() {
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ESP_LOGCONFIG(TAG, "Setting up GRUB boot switch");
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// NVS-backed persistence: hash is "grub_boot_switch::target" + a fixed key
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// so updates stay tied to this component instance.
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pref_ = global_preferences->make_preference<uint8_t>(0x47425354U /* "GBST" */, true);
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uint8_t saved = current_target_.load();
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if (pref_.load(&saved)) {
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current_target_.store(saved);
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ESP_LOGCONFIG(TAG, "Restored target from NVS: %u", saved);
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}
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install_virtual_files_();
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start_usb_();
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}
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void GrubBootSwitch::dump_config() {
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ESP_LOGCONFIG(TAG, "GRUB boot switch:");
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ESP_LOGCONFIG(TAG, " USB VID/PID: %04X:%04X", usb_vid_, usb_pid_);
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ESP_LOGCONFIG(TAG, " Current target: %u", current_target_.load());
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if (!targets_.empty()) {
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ESP_LOGCONFIG(TAG, " Targets:");
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for (const auto &t : targets_)
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ESP_LOGCONFIG(TAG, " %u: %s", t.first, t.second.c_str());
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}
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}
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} // namespace grub_boot_switch
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} // namespace esphome
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