From: Julien Grall <julien.grall@linaro.org>
To: xen-devel@lists.xen.org
Cc: patches@linaro.org, ian.campbell@citrix.com,
Julien Grall <julien.grall@linaro.org>,
Stefano.Stabellini@eu.citrix.com
Subject: [PATCH] drivers/exynos4210: Wait the end of last transfer before initializing the UART
Date: Wed, 22 May 2013 12:50:56 +0100 [thread overview]
Message-ID: <1369223456-3701-1-git-send-email-julien.grall@linaro.org> (raw)
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@linaro.org>
---
xen/drivers/char/exynos4210-uart.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/xen/drivers/char/exynos4210-uart.c b/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;
+#ifdef EARLY_PRINTK
+ /* Flush the UART */
+ while ( !(exynos4210_read(uart, UTRSTAT) & UTRSTAT_TX_EMPTY) )
+ cpu_relax();
+#endif
+
/* reset, TX/RX disables */
exynos4210_write(uart, UCON, 0);
--
1.7.10.4
next reply other threads:[~2013-05-22 11:50 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-22 11:50 Julien Grall [this message]
2013-05-23 11:58 ` [PATCH] drivers/exynos4210: Wait the end of last transfer before initializing the UART Ian Campbell
2013-05-23 12:01 ` Ian Campbell
2013-05-23 13:40 ` Julien Grall
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