[PATCH 8/9] mci: core: fix extract_oid and write to string buffer

[Stefan Kerkmann <s.kerkmann@pengutronix.de>]

The oem id (OID) field is a 2 character long ASCII string for SD cards
and a 8-bit binary number for MMC cards. Both are used in their string
representation.

Signed-off-by: Stefan Kerkmann <s.kerkmann@pengutronix.de>
---
 drivers/mci/mci-core.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/mci/mci-core.c b/drivers/mci/mci-core.c
index 2f0f4c25f8..8907e9dc83 100644
--- a/drivers/mci/mci-core.c
+++ b/drivers/mci/mci-core.c
@@ -1932,11 +1932,18 @@ static unsigned extract_cbx(struct mci *mci)
  * Extract the OEM/Application ID from the CID
  * @param mci Instance data
  *
- * The 'OID' is encoded in bit 119:104 in the CID
+ * The 'OID' is encoded in bit 119:104 in the CID for SD cards and 111:104 for
+ * MMC cards
  */
-static unsigned extract_oid(struct mci *mci)
+static void extract_oid(struct mci *mci, char oid[static 5])
 {
-	return (mci->cid[0] >> 8) & 0xffff;
+	if (IS_SD(mci)) {
+		// SD cards have a 2 character long OEM ID
+		snprintf(oid, 5, "%c%c", UNSTUFF_BITS(mci->cid, 112, 8), UNSTUFF_BITS(mci->cid, 104, 8));
+	} else {
+		// MMC cards have a 8-bit binary number as OEM ID
+		snprintf(oid, 5, "0x%02X", UNSTUFF_BITS(mci->cid, 104, 8));
+	}
 }
 
 /**
@@ -2136,7 +2143,8 @@ static void mci_parse_cid(struct mci *mci) {
 	char buffer[8];
 
 	dev_add_param_uint32_fixed(dev, "cid_mid", extract_mid(mci), "0x%02X");
-	dev_add_param_uint32_fixed(dev, "cid_oid", extract_oid(mci), "0x%04X");
+	extract_oid(mci, buffer);
+	dev_add_param_string_fixed(dev, "cid_oid", buffer);
 	if (!IS_SD(mci))
 		dev_add_param_uint32_fixed(dev, "cid_cbx", extract_cbx(mci), "%u");
 	extract_pnm(mci, buffer);

-- 
2.39.2