serial: add S3C64XX serial driver
Based on the original S3C64XX UART driver by Samsung for U-Boot 1.1.6.
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
diff --git a/drivers/serial/s3c64xx.c b/drivers/serial/s3c64xx.c
new file mode 100644
index 0000000..ea6eb4b
--- /dev/null
+++ b/drivers/serial/s3c64xx.c
@@ -0,0 +1,193 @@
+/*
+ * (C) Copyright 2002
+ * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
+ *
+ * (C) Copyright 2008
+ * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
+ *
+ * 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>
+
+#include <s3c6400.h>
+
+#ifdef CONFIG_SERIAL1
+#define UART_NR S3C64XX_UART0
+
+#elif defined(CONFIG_SERIAL2)
+#define UART_NR S3C64XX_UART1
+
+#elif defined(CONFIG_SERIAL3)
+#define UART_NR S3C64XX_UART2
+
+#else
+#error "Bad: you didn't configure serial ..."
+#endif
+
+#define barrier() asm volatile("" ::: "memory")
+
+/*
+ * The coefficient, used to calculate the baudrate on S3C6400 UARTs is
+ * calculated as
+ * C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT
+ * however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1,
+ * 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants:
+ */
+static const int udivslot[] = {
+ 0,
+ 0x0080,
+ 0x0808,
+ 0x0888,
+ 0x2222,
+ 0x4924,
+ 0x4a52,
+ 0x54aa,
+ 0x5555,
+ 0xd555,
+ 0xd5d5,
+ 0xddd5,
+ 0xdddd,
+ 0xdfdd,
+ 0xdfdf,
+ 0xffdf,
+};
+
+void serial_setbrg(void)
+{
+ DECLARE_GLOBAL_DATA_PTR;
+ s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
+ u32 pclk = get_PCLK();
+ u32 baudrate = gd->baudrate;
+ int i;
+
+ i = (pclk / baudrate) % 16;
+
+ uart->UBRDIV = pclk / baudrate / 16 - 1;
+ uart->UDIVSLOT = udivslot[i];
+
+ for (i = 0; i < 100; i++)
+ barrier();
+}
+
+/*
+ * Initialise the serial port with the given baudrate. The settings
+ * are always 8 data bits, no parity, 1 stop bit, no start bits.
+ */
+int serial_init(void)
+{
+ s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
+
+ /* reset and enable FIFOs, set triggers to the maximum */
+ uart->UFCON = 0xff;
+ uart->UMCON = 0;
+ /* 8N1 */
+ uart->ULCON = 3;
+ /* No interrupts, no DMA, pure polling */
+ uart->UCON = 5;
+
+ serial_setbrg();
+
+ return 0;
+}
+
+/*
+ * Read a single byte from the serial port. Returns 1 on success, 0
+ * otherwise. When the function is succesfull, the character read is
+ * written into its argument c.
+ */
+int serial_getc(void)
+{
+ s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
+
+ /* wait for character to arrive */
+ while (!(uart->UTRSTAT & 0x1));
+
+ return uart->URXH & 0xff;
+}
+
+#ifdef CONFIG_HWFLOW
+static int hwflow; /* turned off by default */
+int hwflow_onoff(int on)
+{
+ switch (on) {
+ case 1:
+ hwflow = 1; /* turn on */
+ break;
+ case -1:
+ hwflow = 0; /* turn off */
+ break;
+ }
+ return hwflow;
+}
+#endif
+
+#ifdef CONFIG_MODEM_SUPPORT
+static int be_quiet;
+void disable_putc(void)
+{
+ be_quiet = 1;
+}
+
+void enable_putc(void)
+{
+ be_quiet = 0;
+}
+#endif
+
+
+/*
+ * Output a single byte to the serial port.
+ */
+void serial_putc(const char c)
+{
+ s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
+
+#ifdef CONFIG_MODEM_SUPPORT
+ if (be_quiet)
+ return;
+#endif
+
+ /* wait for room in the tx FIFO */
+ while (!(uart->UTRSTAT & 0x2));
+
+#ifdef CONFIG_HWFLOW
+ /* Wait for CTS up */
+ while (hwflow && !(uart->UMSTAT & 0x1));
+#endif
+
+ uart->UTXH = c;
+
+ /* If \n, also do \r */
+ if (c == '\n')
+ serial_putc('\r');
+}
+
+/*
+ * Test whether a character is in the RX buffer
+ */
+int serial_tstc(void)
+{
+ s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
+
+ return uart->UTRSTAT & 0x1;
+}
+
+void serial_puts(const char *s)
+{
+ while (*s)
+ serial_putc(*s++);
+}