diff --git a/include/hw/sd/sd.h b/include/hw/sd/sd.h
index 8767ab817c..b58b5a19af 100644
--- a/include/hw/sd/sd.h
+++ b/include/hw/sd/sd.h
@@ -104,8 +104,23 @@ typedef struct {
     /*< public >*/
 
     int (*do_command)(SDState *sd, SDRequest *req, uint8_t *response);
-    void (*write_data)(SDState *sd, uint8_t value);
-    uint8_t (*read_data)(SDState *sd);
+    /**
+     * Write a byte to a SD card.
+     * @sd: card
+     * @value: byte to write
+     *
+     * Write a byte on the data lines of a SD card.
+     */
+    void (*write_byte)(SDState *sd, uint8_t value);
+    /**
+     * Read a byte from a SD card.
+     * @sd: card
+     *
+     * Read a byte from the data lines of a SD card.
+     *
+     * Return: byte value read
+     */
+    uint8_t (*read_byte)(SDState *sd);
     bool (*data_ready)(SDState *sd);
     void (*set_voltage)(SDState *sd, uint16_t millivolts);
     uint8_t (*get_dat_lines)(SDState *sd);
diff --git a/include/hw/sd/sdcard_legacy.h b/include/hw/sd/sdcard_legacy.h
index 8681f8089b..0dc3889555 100644
--- a/include/hw/sd/sdcard_legacy.h
+++ b/include/hw/sd/sdcard_legacy.h
@@ -34,8 +34,8 @@
 /* Legacy functions to be used only by non-qdevified callers */
 SDState *sd_init(BlockBackend *blk, bool is_spi);
 int sd_do_command(SDState *card, SDRequest *request, uint8_t *response);
-void sd_write_data(SDState *card, uint8_t value);
-uint8_t sd_read_data(SDState *card);
+void sd_write_byte(SDState *card, uint8_t value);
+uint8_t sd_read_byte(SDState *card);
 void sd_set_cb(SDState *card, qemu_irq readonly, qemu_irq insert);
 
 /* sd_enable should not be used -- it is only used on the nseries boards,
diff --git a/hw/sd/core.c b/hw/sd/core.c
index abec48bccb..79d96576ea 100644
--- a/hw/sd/core.c
+++ b/hw/sd/core.c
@@ -110,7 +110,7 @@ void sdbus_write_data(SDBus *sdbus, uint8_t value)
     if (card) {
         SDCardClass *sc = SD_CARD_GET_CLASS(card);
 
-        sc->write_data(card, value);
+        sc->write_byte(card, value);
     }
 }
 
@@ -122,7 +122,7 @@ uint8_t sdbus_read_data(SDBus *sdbus)
     if (card) {
         SDCardClass *sc = SD_CARD_GET_CLASS(card);
 
-        value = sc->read_data(card);
+        value = sc->read_byte(card);
     }
     trace_sdbus_read(sdbus_name(sdbus), value);
 
diff --git a/hw/sd/omap_mmc.c b/hw/sd/omap_mmc.c
index 7d33c59226..1f946908fe 100644
--- a/hw/sd/omap_mmc.c
+++ b/hw/sd/omap_mmc.c
@@ -232,10 +232,10 @@ static void omap_mmc_transfer(struct omap_mmc_s *host)
             if (host->fifo_len > host->af_level)
                 break;
 
-            value = sd_read_data(host->card);
+            value = sd_read_byte(host->card);
             host->fifo[(host->fifo_start + host->fifo_len) & 31] = value;
             if (-- host->blen_counter) {
-                value = sd_read_data(host->card);
+                value = sd_read_byte(host->card);
                 host->fifo[(host->fifo_start + host->fifo_len) & 31] |=
                         value << 8;
                 host->blen_counter --;
@@ -247,10 +247,10 @@ static void omap_mmc_transfer(struct omap_mmc_s *host)
                 break;
 
             value = host->fifo[host->fifo_start] & 0xff;
-            sd_write_data(host->card, value);
+            sd_write_byte(host->card, value);
             if (-- host->blen_counter) {
                 value = host->fifo[host->fifo_start] >> 8;
-                sd_write_data(host->card, value);
+                sd_write_byte(host->card, value);
                 host->blen_counter --;
             }
 
diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index 5c6f5c94f3..7c9d956f11 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -1809,7 +1809,7 @@ static void sd_blk_write(SDState *sd, uint64_t addr, uint32_t len)
 #define APP_READ_BLOCK(a, len)	memset(sd->data, 0xec, len)
 #define APP_WRITE_BLOCK(a, len)
 
-void sd_write_data(SDState *sd, uint8_t value)
+void sd_write_byte(SDState *sd, uint8_t value)
 {
     int i;
 
@@ -1818,7 +1818,7 @@ void sd_write_data(SDState *sd, uint8_t value)
 
     if (sd->state != sd_receivingdata_state) {
         qemu_log_mask(LOG_GUEST_ERROR,
-                      "sd_write_data: not in Receiving-Data state\n");
+                      "%s: not in Receiving-Data state\n", __func__);
         return;
     }
 
@@ -1940,7 +1940,7 @@ void sd_write_data(SDState *sd, uint8_t value)
         break;
 
     default:
-        qemu_log_mask(LOG_GUEST_ERROR, "sd_write_data: unknown command\n");
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: unknown command\n", __func__);
         break;
     }
 }
@@ -1959,7 +1959,7 @@ static const uint8_t sd_tuning_block_pattern[SD_TUNING_BLOCK_SIZE] = {
     0xbb, 0xff, 0xf7, 0xff,         0xf7, 0x7f, 0x7b, 0xde,
 };
 
-uint8_t sd_read_data(SDState *sd)
+uint8_t sd_read_byte(SDState *sd)
 {
     /* TODO: Append CRCs */
     uint8_t ret;
@@ -1970,7 +1970,7 @@ uint8_t sd_read_data(SDState *sd)
 
     if (sd->state != sd_sendingdata_state) {
         qemu_log_mask(LOG_GUEST_ERROR,
-                      "sd_read_data: not in Sending-Data state\n");
+                      "%s: not in Sending-Data state\n", __func__);
         return 0x00;
     }
 
@@ -2076,7 +2076,7 @@ uint8_t sd_read_data(SDState *sd)
         break;
 
     default:
-        qemu_log_mask(LOG_GUEST_ERROR, "sd_read_data: unknown command\n");
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: unknown command\n", __func__);
         return 0x00;
     }
 
@@ -2192,8 +2192,8 @@ static void sd_class_init(ObjectClass *klass, void *data)
     sc->get_dat_lines = sd_get_dat_lines;
     sc->get_cmd_line = sd_get_cmd_line;
     sc->do_command = sd_do_command;
-    sc->write_data = sd_write_data;
-    sc->read_data = sd_read_data;
+    sc->write_byte = sd_write_byte;
+    sc->read_byte = sd_read_byte;
     sc->data_ready = sd_data_ready;
     sc->enable = sd_enable;
     sc->get_inserted = sd_get_inserted;
