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[Xen-devel] [PATCH] drivers/exynos4210: Wait the end of last transfer before initializing the UART

When early printk is enabled by the user, it's possible to loose the last
characters if the UART is initialized without waiting that the last transfer
was completed.

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
 xen/drivers/char/exynos4210-uart.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/xen/drivers/char/exynos4210-uart.c 
index f7971da..13758d4 100644
--- a/xen/drivers/char/exynos4210-uart.c
+++ b/xen/drivers/char/exynos4210-uart.c
@@ -104,6 +104,12 @@ static void __init exynos4210_uart_init_preirq(struct 
serial_port *port)
     unsigned int divisor;
     uint32_t ulcon;
+    /* Flush the UART */
+    while ( !(exynos4210_read(uart, UTRSTAT) &  UTRSTAT_TX_EMPTY) )
+        cpu_relax();
     /* reset, TX/RX disables */
     exynos4210_write(uart, UCON, 0);

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