1 files changed, 24 insertions, 0 deletions

diff --git a/hw/char/exynos4210_uart.c b/hw/char/exynos4210_uart.c
index 363393cc75..20d8509107 100644
--- a/hw/char/exynos4210_uart.c
+++ b/hw/char/exynos4210_uart.c
@@ -154,6 +154,7 @@ typedef struct Exynos4210UartState {
 
     CharBackend       chr;
     qemu_irq          irq;
+    qemu_irq          dmairq;
 
     uint32_t channel;
 
@@ -261,6 +262,24 @@ exynos4210_uart_Rx_FIFO_trigger_level(const Exynos4210UartState *s)
     return exynos4210_uart_FIFO_trigger_level(s->channel, reg);
 }
 
+/*
+ * Update Rx DMA busy signal if Rx DMA is enabled. For simplicity,
+ * mark DMA as busy if DMA is enabled and the receive buffer is empty.
+ */
+static void exynos4210_uart_update_dmabusy(Exynos4210UartState *s)
+{
+    bool rx_dma_enabled = (s->reg[I_(UCON)] & 0x03) == 0x02;
+    uint32_t count = fifo_elements_number(&s->rx);
+
+    if (rx_dma_enabled && !count) {
+        qemu_irq_raise(s->dmairq);
+        trace_exynos_uart_dmabusy(s->channel);
+    } else {
+        qemu_irq_lower(s->dmairq);
+        trace_exynos_uart_dmaready(s->channel);
+    }
+}
+
 static void exynos4210_uart_update_irq(Exynos4210UartState *s)
 {
     /*
@@ -282,10 +301,12 @@ static void exynos4210_uart_update_irq(Exynos4210UartState *s)
         count = fifo_elements_number(&s->rx);
         if ((count && !(s->reg[I_(UCON)] & 0x80)) ||
             count >= exynos4210_uart_Rx_FIFO_trigger_level(s)) {
+            exynos4210_uart_update_dmabusy(s);
             s->reg[I_(UINTSP)] |= UINTSP_RXD;
             timer_del(s->fifo_timeout_timer);
         }
     } else if (s->reg[I_(UTRSTAT)] & UTRSTAT_Rx_BUFFER_DATA_READY) {
+        exynos4210_uart_update_dmabusy(s);
         s->reg[I_(UINTSP)] |= UINTSP_RXD;
     }
 
@@ -311,6 +332,7 @@ static void exynos4210_uart_timeout_int(void *opaque)
         (s->reg[I_(UCON)] & (1 << 11))) {
         s->reg[I_(UINTSP)] |= UINTSP_RXD;
         s->reg[I_(UTRSTAT)] |= UTRSTAT_Rx_TIMEOUT;
+        exynos4210_uart_update_dmabusy(s);
         exynos4210_uart_update_irq(s);
     }
 }
@@ -495,6 +517,7 @@ static uint64_t exynos4210_uart_read(void *opaque, hwaddr offset,
             s->reg[I_(UTRSTAT)] &= ~UTRSTAT_Rx_BUFFER_DATA_READY;
             res = s->reg[I_(URXH)];
         }
+        exynos4210_uart_update_dmabusy(s);
         trace_exynos_uart_read(s->channel, offset,
                                exynos4210_uart_regname(offset), res);
         return res;
@@ -661,6 +684,7 @@ static void exynos4210_uart_init(Object *obj)
     sysbus_init_mmio(dev, &s->iomem);
 
     sysbus_init_irq(dev, &s->irq);
+    sysbus_init_irq(dev, &s->dmairq);
 }
 
 static void exynos4210_uart_realize(DeviceState *dev, Error **errp)