From: Hans-Erik Floryd <hans-erik.floryd@rt-labs.com>

Add the ESDHC PRSSTAT_SDSTB bit, using the value of SDHC_CLOCK_INT_STABLE.
Freescale recommends checking this bit when changing clock frequency.

Signed-off-by: Hans-Erik Floryd <hans-erik.floryd@rt-labs.com>
Message-id: 1534507843-4251-1-git-send-email-hans-erik.floryd@rt-labs.com
[PMM: fixed indentation]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/sd/sdhci-internal.h | 2 ++
 hw/sd/sdhci.c          | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/hw/sd/sdhci-internal.h b/hw/sd/sdhci-internal.h
index 756ef3f3c2e..19665fd4013 100644
--- a/hw/sd/sdhci-internal.h
+++ b/hw/sd/sdhci-internal.h
@@ -302,4 +302,6 @@ extern const VMStateDescription sdhci_vmstate;
 #define ESDHC_CTRL_4BITBUS              (0x1 << 1)
 #define ESDHC_CTRL_8BITBUS              (0x2 << 1)
 
+#define ESDHC_PRNSTS_SDSTB              (1 << 3)
+
 #endif
diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
index 8f58c31265a..81bbf032794 100644
--- a/hw/sd/sdhci.c
+++ b/hw/sd/sdhci.c
@@ -1651,6 +1651,14 @@ static uint64_t usdhc_read(void *opaque, hwaddr offset, unsigned size)
 
         break;
 
+    case SDHC_PRNSTS:
+        /* Add SDSTB (SD Clock Stable) bit to PRNSTS */
+        ret = sdhci_read(opaque, offset, size) & ~ESDHC_PRNSTS_SDSTB;
+        if (s->clkcon & SDHC_CLOCK_INT_STABLE) {
+            ret |= ESDHC_PRNSTS_SDSTB;
+        }
+        break;
+
     case ESDHC_DLL_CTRL:
     case ESDHC_TUNE_CTRL_STATUS:
     case ESDHC_UNDOCUMENTED_REG27:
-- 
2.18.0