uart/ns16550: implements new API of line control

This implements the newly introduced APIs to manipulate line controls
for UART.

This also implements the driver command API as setting baud rate
may require setting the DLF.

Change-Id: I80634aa3fbd4a3223c46edb61417123e36f439dd
Signed-off-by: Daniel Leung <daniel.leung@intel.com>

drivers/serial/Kconfig.ns16550

@@ -47,6 +47,25 @@ config UART_NS16550_DLF
 
 	  Says n if you are not sure if hardware supports this.
 
+config UART_NS16550_LINE_CTRL
+	bool "Enable Serial Line Control for Apps"
+	default n
+	depends on UART_LINE_CTRL && UART_NS16550
+	help
+	  This enables the API for apps to control the serial line,
+	  such as CTS and RTS.
+
+	  Says n if not sure.
+
+config UART_NS16550_DRV_CMD
+	bool "Enable Driver Commands"
+	default n
+	depends on UART_DRV_CMD && UART_NS16550
+	help
+	  This enables the API for apps to send commands to driver.
+
+	  Says n if not sure.
+
 # ---------- Port 0 ----------
 
 menuconfig UART_NS16550_PORT_0

drivers/serial/uart_ns16550.c

@@ -46,6 +46,8 @@
 #include <pci/pci_mgr.h>
 #endif /* CONFIG_PCI */
 
+#include "uart_ns16550.h"
+
 /* register definitions */
 
 #define REG_THR 0x00  /* Transmitter holding reg. */
@@ -221,6 +223,25 @@ static inline void set_dlf(struct device *dev, uint32_t val)
 }
 #endif
 
+static void set_baud_rate(struct device *dev, uint32_t baud_rate)
+{
+	struct uart_device_config * const dev_cfg = DEV_CFG(dev);
+	struct uart_ns16550_dev_data_t * const dev_data = DEV_DATA(dev);
+	uint32_t divisor; /* baud rate divisor */
+
+	if ((baud_rate != 0) && (dev_cfg->sys_clk_freq != 0)) {
+		/* calculate baud rate divisor */
+		divisor = (dev_cfg->sys_clk_freq / baud_rate) >> 4;
+
+		/* set the DLAB to access the baud rate divisor registers */
+		OUTBYTE(LCR(dev), LCR_DLAB);
+		OUTBYTE(BRDL(dev), (unsigned char)(divisor & 0xff));
+		OUTBYTE(BRDH(dev), (unsigned char)((divisor >> 8) & 0xff));
+
+		dev_data->baud_rate = baud_rate;
+	}
+}
+
 #if defined(CONFIG_UART_NS16550_PCI)
 
 static inline int ns16550_pci_uart_scan(struct device *dev)
@@ -264,11 +285,9 @@ static inline int ns16550_pci_uart_scan(struct device *dev)
  */
 static int uart_ns16550_init(struct device *dev)
 {
-	struct uart_device_config * const dev_cfg = DEV_CFG(dev);
 	struct uart_ns16550_dev_data_t * const dev_data = DEV_DATA(dev);
 
 	int old_level;     /* old interrupt lock level */
-	uint32_t divisor; /* baud rate divisor */
 	uint8_t mdc = 0;
 
 	if (!ns16550_pci_uart_scan(dev)) {
@@ -279,15 +298,7 @@ static int uart_ns16550_init(struct device *dev)
 
 	old_level = irq_lock();
 
-	if ((dev_data->baud_rate != 0) && (dev_cfg->sys_clk_freq != 0)) {
-		/* calculate baud rate divisor */
-		divisor = (dev_cfg->sys_clk_freq / dev_data->baud_rate) >> 4;
-
-		/* set the DLAB to access the baud rate divisor registers */
-		OUTBYTE(LCR(dev), LCR_DLAB);
-		OUTBYTE(BRDL(dev), (unsigned char)(divisor & 0xff));
-		OUTBYTE(BRDH(dev), (unsigned char)((divisor >> 8) & 0xff));
-	}
+	set_baud_rate(dev, dev_data->baud_rate);
 
 #ifdef CONFIG_UART_NS16550_DLF
 	set_dlf(dev, dev_data->dlf);
@@ -549,6 +560,79 @@ static unsigned int uart_ns16550_irq_get(struct device *dev)
 
 #endif /* CONFIG_UART_INTERRUPT_DRIVEN */
 
+#ifdef CONFIG_UART_NS16550_LINE_CTRL
+
+/**
+ * @brief Manipualte line control for UART.
+ *
+ * @param dev UART device struct (of type struct uart_device_config_t)
+ * @param ctrl The line control to be manipulated
+ * @param val Value to set the line control
+ *
+ * @return DEV_OK if successful, failed otherwise
+ */
+static int uart_ns16550_line_ctrl_set(struct device *dev,
+				      uint32_t ctrl, uint32_t val)
+{
+	uint32_t mdc, chg;
+
+	switch (ctrl) {
+	case LINE_CTRL_BAUD_RATE:
+		set_baud_rate(dev, val);
+		return DEV_OK;
+
+	case LINE_CTRL_RTS:
+	case LINE_CTRL_DTR:
+		mdc = INBYTE(MDC(dev));
+
+		if (ctrl == LINE_CTRL_RTS) {
+			chg = MCR_RTS;
+		} else {
+			chg = MCR_DTR;
+		}
+
+		if (val) {
+			mdc |= chg;
+		} else {
+			mdc &= ~(chg);
+		}
+		OUTBYTE(MDC(dev), mdc);
+		return DEV_OK;
+	}
+
+	return DEV_INVALID_OP;
+}
+
+#endif /* CONFIG_UART_NS16550_LINE_CTRL */
+
+#ifdef CONFIG_UART_NS16550_DRV_CMD
+
+/**
+ * @brief Send extra command to driver
+ *
+ * @param dev UART device struct (of type struct uart_device_config_t)
+ * @param cmd Command to driver
+ * @param p Parameter to the command
+ *
+ * @return DEV_OK if successful, failed otherwise
+ */
+static int uart_ns16550_drv_cmd(struct device *dev, uint32_t cmd, uint32_t p)
+{
+	switch (cmd) {
+
+#ifdef CONFIG_UART_NS16550_DLF
+	case CMD_SET_DLF:
+		set_dlf(dev, p);
+		return DEV_OK;
+#endif
+
+	}
+
+	return DEV_INVALID_OP;
+}
+
+#endif /* CONFIG_UART_NS16550_DRV_CMD */
+
 
 static struct uart_driver_api uart_ns16550_driver_api = {
 	.poll_in = uart_ns16550_poll_in,
@@ -571,6 +655,14 @@ static struct uart_driver_api uart_ns16550_driver_api = {
 	.irq_get = uart_ns16550_irq_get,
 
 #endif
+
+#ifdef CONFIG_UART_NS16550_LINE_CTRL
+	.line_ctrl_set = uart_ns16550_line_ctrl_set,
+#endif
+
+#ifdef CONFIG_UART_NS16550_DRV_CMD
+	.drv_cmd = uart_ns16550_drv_cmd,
+#endif
 };
 
 #ifdef CONFIG_UART_NS16550_PORT_0

drivers/serial/uart_ns16550.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2015 Intel Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @file Header file for the NS16550 UART
+ */
+
+#ifndef _UART_NS16550_H_
+#define _UART_NS16550_H_
+
+#define CMD_SET_DLF	0x01
+
+#endif /* _UART_NS16550_H_ */