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

lib/SD/src/sd_diskio.cpp

@@ -920,6 +920,26 @@ uint32_t sdcard_sector_size(uint8_t pdrv) {
   return 512;
 }
 
+// roro: the card's CID. CMD10 in SPI mode (the enum's SEND_CID, 2, is the SD-mode command).
+namespace roro {
+bool sdReadCid(uint8_t cid[16]) {
+  for (uint8_t pdrv = 0; pdrv < FF_VOLUMES; ++pdrv) {
+    ardu_sdcard_t *card = s_cards[pdrv];
+    if (!card) {
+      continue;
+    }
+    AcquireSPI lock(card);
+    if (!sdSelectCard(pdrv)) {
+      return false;
+    }
+    bool ok = !sdCommand(pdrv, 10, 0, NULL) && sdReadBytes(pdrv, (char *)cid, 16);
+    sdDeselectCard(pdrv);
+    return ok;
+  }
+  return false;
+}
+}  // namespace roro
+
 sdcard_type_t sdcard_type(uint8_t pdrv) {
   ardu_sdcard_t *card = s_cards[pdrv];
   if (pdrv >= FF_VOLUMES || card == NULL) {

lib/SD/src/sd_fault.h

@@ -26,4 +26,8 @@ struct SdFault {
 
 SdFault sdLastFault();
 
+// The mounted card's identity register (CID, CMD10): who made it, its name, serial and date.
+// Call it where card access is allowed (the storage task).
+bool sdReadCid(uint8_t cid[16]);
+
 }  // namespace roro