Add common serial driver for Atmel AT32 and AT91 chips

Patch by Haavard Skinnemoen, 06 Sep 2006

This is a first attempt at creating a common serial driver for Atmel
chips. For now, it supports the AT32AP7000 AVR32 chip, but it should
be possible to support AT91RM9200 and other ARM-based chips with some
minor modifications.

There's nothing fundamentally AVR32-specific in this driver, but it
does use some features which are currently only defined for the
AT32AP CPU port:
  * pm_get_clock_freq: Obtain the clock frequency of a given domain
  * gd->console_uart: A "struct device" containing information about
    register mappings, gpio resources and clocks associated with the
    UART device.

For more information about these features, please see the "AT32AP
CPU" patch.

1 files changed, 88 insertions, 0 deletions

diff --git a/drivers/atmel_usart.c b/drivers/atmel_usart.c
new file mode 100644
index 0000000..41c3768
--- /dev/null
+++ b/drivers/atmel_usart.c
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2004-2006 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include <common.h>
+
+#ifdef CONFIG_ATMEL_USART
+#include <asm/io.h>
+#include <asm/arch/platform.h>
+
+#include "atmel_usart.h"
+
+DECLARE_GLOBAL_DATA_PTR;
+
+void serial_setbrg(void)
+{
+	unsigned long divisor;
+	unsigned long usart_hz;
+
+	/*
+	 *              Master Clock
+	 * Baud Rate = --------------
+	 *                16 * CD
+	 */
+	usart_hz = pm_get_clock_freq(gd->console_uart->resource[0].u.clock.id);
+	divisor = (usart_hz / 16 + gd->baudrate / 2) / gd->baudrate;
+	usart3_writel(gd->console_uart, BRGR, USART3_BF(CD, divisor));
+}
+
+int serial_init(void)
+{
+	usart3_writel(gd->console_uart, CR,
+		      USART3_BIT(RSTRX) | USART3_BIT(RSTTX));
+
+	serial_setbrg();
+
+	usart3_writel(gd->console_uart, CR,
+		      USART3_BIT(RXEN) | USART3_BIT(TXEN));
+	usart3_writel(gd->console_uart, MR,
+		      USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL)
+		      | USART3_BF(USCLKS, USART3_USCLKS_MCK)
+		      | USART3_BF(CHRL, USART3_CHRL_8)
+		      | USART3_BF(PAR, USART3_PAR_NONE)
+		      | USART3_BF(NBSTOP, USART3_NBSTOP_1));
+
+	return 0;
+}
+
+void serial_putc(char c)
+{
+	if (c == '\n')
+		serial_putc('\r');
+
+	while (!(usart3_readl(gd->console_uart, CSR) & USART3_BIT(TXRDY))) ;
+	usart3_writel(gd->console_uart, THR, c);
+}
+
+void serial_puts(const char *s)
+{
+	while (*s)
+		serial_putc(*s++);
+}
+
+int serial_getc(void)
+{
+	while (!(usart3_readl(gd->console_uart, CSR) & USART3_BIT(RXRDY))) ;
+	return usart3_readl(gd->console_uart, RHR);
+}
+
+int serial_tstc(void)
+{
+	return (usart3_readl(gd->console_uart, CSR) & USART3_BIT(RXRDY)) != 0;
+}
+
+#endif /* CONFIG_ATMEL_USART */