From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Date: Mon, 6 Jan 2014 10:16:40 +0000 (+0000)
Subject: char/cadence_uart: Use the TX fifo for transmission
X-Git-Tag: TizenStudio_2.0_p2.3.2~208^2~1143^2~32
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9e263f73912ba35510d7d7be4c40ba871d4b57e2;p=sdk%2Femulator%2Fqemu.git

char/cadence_uart: Use the TX fifo for transmission

Populate the TxFIFO with the Tx data before sending. Prepares
support for proper Tx flow control implementation.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: bdf7f8af2ef02839bea18665701bc2612f7baa6f.1388626249.git.peter.crosthwaite@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---

diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
index 3bcaf29..be32126 100644
--- a/hw/char/cadence_uart.c
+++ b/hw/char/cadence_uart.c
@@ -292,7 +292,22 @@ static void uart_write_tx_fifo(UartState *s, const uint8_t *buf, int size)
         return;
     }
 
-    qemu_chr_fe_write_all(s->chr, buf, size);
+    if (size > TX_FIFO_SIZE - s->tx_count) {
+        size = TX_FIFO_SIZE - s->tx_count;
+        /*
+         * This can only be a guest error via a bad tx fifo register push,
+         * as can_receive() should stop remote loop and echo modes ever getting
+         * us to here.
+         */
+        qemu_log_mask(LOG_GUEST_ERROR, "cadence_uart: TxFIFO overflow");
+        s->r[R_CISR] |= UART_INTR_ROVR;
+    }
+
+    memcpy(s->tx_fifo + s->tx_count, buf, size);
+    s->tx_count += size;
+
+    qemu_chr_fe_write_all(s->chr, s->tx_fifo, s->tx_count);
+    s->tx_count = 0;
 }
 
 static void uart_receive(void *opaque, const uint8_t *buf, int size)