sd card: what the card says it is, from its CID register

Type, size, and the identity register read by our SD driver (CMD10): manufacturer, OEM, product name, revision, serial and date, decoded by a host-tested parser. Needed for the upstream report of #21: nothing else here could read the card's identity. This one is a Samsung 8 GB SDHC from June 2013. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT
2026-10-05 23:15:29 +02:00
parent 3f2650c56e
commit 370f067fbf
7 changed files with 173 additions and 1 deletions
@@ -0,0 +1,53 @@
+#include "sd_card_id.h"
+
+#include <cstdio>
+
+namespace roro {
+
+namespace {
+char printable(uint8_t b) { return b >= 0x20 && b < 0x7F ? static_cast<char>(b) : '?'; }
+}  // namespace
+
+SdCardId parseSdCid(const uint8_t cid[16]) {
+    SdCardId id;
+    id.manufacturer = cid[0];
+    for (int i = 0; i < 2; ++i) id.oem[i] = printable(cid[1 + i]);
+    for (int i = 0; i < 5; ++i) id.product[i] = printable(cid[3 + i]);
+    id.revisionMajor = cid[8] >> 4;
+    id.revisionMinor = cid[8] & 0x0F;
+    id.serial = static_cast<uint32_t>(cid[9]) << 24 | cid[10] << 16 | cid[11] << 8 | cid[12];
+    // 4 reserved bits, 8 bits of year since 2000, 4 bits of month.
+    id.year = 2000 + (((cid[13] & 0x0F) << 4) | (cid[14] >> 4));
+    id.month = cid[14] & 0x0F;
+    return id;
+}
+
+const char* sdManufacturerName(uint8_t id) {
+    switch (id) {
+        case 0x01: return "Panasonic";
+        case 0x02: return "Toshiba/Kioxia";
+        case 0x03: return "SanDisk";
+        case 0x1B: return "Samsung";
+        case 0x1D: return "ADATA";
+        case 0x27: return "Phison";
+        case 0x28: return "Lexar";
+        case 0x31: return "Silicon Power";
+        case 0x41: return "Kingston";
+        case 0x74: return "Transcend";
+        case 0x76: return "Patriot";
+        case 0x82: return "Sony";
+        case 0x9C: return "Angelbird/Hoodman";
+        case 0xAD: return "Longsys/Lexar";
+        default: return "unknown";
+    }
+}
+
+std::string sdCardSummary(const SdCardId& id) {
+    char s[112];
+    std::snprintf(s, sizeof s, "%s (0x%02X) \"%s\" \"%s\" rev %u.%u, serial %08x, made %04d-%02d",
+                  sdManufacturerName(id.manufacturer), id.manufacturer, id.oem, id.product, id.revisionMajor,
+                  id.revisionMinor, static_cast<unsigned>(id.serial), id.year, id.month);
+    return s;
+}
+
+}  // namespace roro
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+namespace roro {
+
+// What an SD card says it is: its CID register, 16 bytes (SD Physical Layer spec, 5.2).
+struct SdCardId {
+    uint8_t manufacturer = 0;  // assigned by the SD Association; see sdManufacturerName()
+    char oem[3] = {};          // two characters
+    char product[6] = {};      // five characters
+    uint8_t revisionMajor = 0, revisionMinor = 0;
+    uint32_t serial = 0;
+    int year = 0, month = 0;  // manufactured
+};
+
+SdCardId parseSdCid(const uint8_t cid[16]);
+
+// The usual holder of a manufacturer ID. The SD Association doesn't publish its list: these are
+// the commonly reported ones, and resold or counterfeit cards carry whatever their maker chose.
+const char* sdManufacturerName(uint8_t id);
+
+// "SanDisk (0x03) "SD" "SU08G" rev 8.0, serial 1234abcd, made 2014-03".
+std::string sdCardSummary(const SdCardId& id);
+
+}  // namespace roro