linux-kernel - Re: [PATCH] Add poll_get_char and poll_put_char uart_ops to atmel

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Message-ID: <20090727151900.GB4052@pc-ras4041.res.insa>
Date:	Mon, 27 Jul 2009 17:19:00 +0200
From:	Albin Tonnerre <albin.tonnerre@...e-electrons.com>
To:	Haavard Skinnemoen <haavard.skinnemoen@...el.com>
Cc:	avictor.za@...il.com, linux-kernel@...r.kernel.org,
	Nicolas Ferre <nicolas.ferre@...el.com>
Subject: Re: [PATCH] Add poll_get_char and poll_put_char uart_ops to
	atmel_serial.

This patch allows using KGDB over the console with the atmel_serial
driver.

Signed-off-by: Albin Tonnerre <albin.tonnerre@...e-electrons.com>
---
 Updated patch to use __raw_readl/__raw_writel, as per Haavard's comments.

 drivers/serial/atmel_serial.c |   26 ++++++++++++++++++++++++++
 1 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 338b15c..1e65046 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -1213,6 +1213,28 @@ static int atmel_verify_port(struct uart_port *port, struct serial_struct *ser)
 	return ret;
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+static int atmel_poll_get_char(struct uart_port *port)
+{
+	struct atmel_uart_port *aup = to_atmel_uart_port(port);
+
+	while (!(__raw_readl(aup->uart.membase + ATMEL_US_CSR) & ATMEL_US_RXRDY))
+		barrier();
+
+	return __raw_readl(aup->uart.membase + ATMEL_US_RHR);
+}
+
+static void atmel_poll_put_char(struct uart_port *port, unsigned char ch)
+{
+	struct atmel_uart_port *aup = to_atmel_uart_port(port);
+
+	while (!(__raw_readl(aup->uart.membase + ATMEL_US_CSR) & ATMEL_US_TXRDY))
+		barrier();
+
+	__raw_writel(ch, aup->uart.membase + ATMEL_US_THR);
+}
+#endif
+
 static struct uart_ops atmel_pops = {
 	.tx_empty	= atmel_tx_empty,
 	.set_mctrl	= atmel_set_mctrl,
@@ -1232,6 +1254,10 @@ static struct uart_ops atmel_pops = {
 	.config_port	= atmel_config_port,
 	.verify_port	= atmel_verify_port,
 	.pm		= atmel_serial_pm,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_get_char	= atmel_poll_get_char,
+	.poll_put_char	= atmel_poll_put_char,
+#endif
 };
 
 /*
-- 
Albin Tonnerre, Free Electrons
Kernel, drivers and embedded Linux development,
consulting, training and support.
http://free-electrons.com
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