Rather than using the obscure 0x4567 magic value,
use a real random one.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Cédric Le Goater <clg@redhat.com>
---
 hw/sd/sd.c         | 11 ++++++++---
 hw/sd/trace-events |  1 +
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index 5997e13107..d85b2906f4 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -46,6 +46,7 @@
 #include "qemu/error-report.h"
 #include "qemu/timer.h"
 #include "qemu/log.h"
+#include "qemu/guest-random.h"
 #include "qemu/module.h"
 #include "sdmmc-internal.h"
 #include "trace.h"
@@ -488,9 +489,10 @@ static void sd_set_csd(SDState *sd, uint64_t size)
 
 /* Relative Card Address register */
 
-static void sd_set_rca(SDState *sd)
+static void sd_set_rca(SDState *sd, uint16_t value)
 {
-    sd->rca += 0x4567;
+    trace_sdcard_set_rca(value);
+    sd->rca = value;
 }
 
 static uint16_t sd_req_get_rca(SDState *s, SDRequest req)
@@ -1113,11 +1115,14 @@ static sd_rsp_type_t sd_cmd_ALL_SEND_CID(SDState *sd, SDRequest req)
 /* CMD3 */
 static sd_rsp_type_t sd_cmd_SEND_RELATIVE_ADDR(SDState *sd, SDRequest req)
 {
+    uint16_t random_rca;
+
     switch (sd->state) {
     case sd_identification_state:
     case sd_standby_state:
         sd->state = sd_standby_state;
-        sd_set_rca(sd);
+        qemu_guest_getrandom_nofail(&random_rca, sizeof(random_rca));
+        sd_set_rca(sd, random_rca);
         return sd_r6;
 
     default:
diff --git a/hw/sd/trace-events b/hw/sd/trace-events
index 43eaeba149..6a51b0e906 100644
--- a/hw/sd/trace-events
+++ b/hw/sd/trace-events
@@ -43,6 +43,7 @@ sdcard_response(const char *rspdesc, int rsplen) "%s (sz:%d)"
 sdcard_powerup(void) ""
 sdcard_inquiry_cmd41(void) ""
 sdcard_reset(void) ""
+sdcard_set_rca(uint16_t value) "new RCA: 0x%04x"
 sdcard_set_blocklen(uint16_t length) "block len 0x%03x"
 sdcard_set_block_count(uint32_t cnt) "block cnt 0x%"PRIx32
 sdcard_inserted(bool readonly) "read_only: %u"
-- 
2.41.0