OrgZephyr/zephyr
OrgZephyr
/
zephyr
mirror of https://github.com/zephyrproject-rtos/zephyr.git
1
0
Fork 0
Code Issues Releases Wiki Activity
zephyr/drivers/serial/ns16550.c

541 lines
15 KiB
C
Raw Blame History

/* ns16550.c - NS16550D serial driver */
/*
* Copyright (c) 2010, 2012-2015 Wind River Systems, Inc.
*
* 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.
*/
/**
* @brief NS16550 Serial Driver
*
* This is the driver for the Intel NS16550 UART Chip used on the PC 386.
* It uses the SCCs in asynchronous mode only.
*
* Before individual UART port can be used, ns16550_uart_port_init() has to be
* called to setup the port.
*
* - the following macro for the number of bytes between register addresses:
*
* UART_REG_ADDR_INTERVAL
*/
#include <nanokernel.h>
#include <arch/cpu.h>
#include <stdint.h>
#include <board.h>
#include <toolchain.h>
#include <sections.h>
#include <uart.h>
#include <sys_io.h>
#ifdef CONFIG_PCI
#include <pci/pci.h>
#include <pci/pci_mgr.h>
#endif /* CONFIG_PCI */
#include "ns16550.h"
/* register definitions */
#define REG_THR 0x00 /* Transmitter holding reg. */
#define REG_RDR 0x00 /* Receiver data reg. */
#define REG_BRDL 0x00 /* Baud rate divisor (LSB) */
#define REG_BRDH 0x01 /* Baud rate divisor (MSB) */
#define REG_IER 0x01 /* Interrupt enable reg. */
#define REG_IIR 0x02 /* Interrupt ID reg. */
#define REG_FCR 0x02 /* FIFO control reg. */
#define REG_LCR 0x03 /* Line control reg. */
#define REG_MDC 0x04 /* Modem control reg. */
#define REG_LSR 0x05 /* Line status reg. */
#define REG_MSR 0x06 /* Modem status reg. */
/* equates for interrupt enable register */
#define IER_RXRDY 0x01 /* receiver data ready */
#define IER_TBE 0x02 /* transmit bit enable */
#define IER_LSR 0x04 /* line status interrupts */
#define IER_MSI 0x08 /* modem status interrupts */
/* equates for interrupt identification register */
#define IIR_IP 0x01 /* interrupt pending bit */
#define IIR_MASK 0x07 /* interrupt id bits mask */
#define IIR_MSTAT 0x00 /* modem status interrupt */
#define IIR_THRE 0X02 /* transmit holding register empty */
#define IIR_RBRF 0x04 /* receiver buffer register full */
#define IIR_ID 0x06 /* interupt ID mask without IP */
#define IIR_SEOB 0x06 /* serialization error or break */
/* equates for FIFO control register */
#define FCR_FIFO 0x01 /* enable XMIT and RCVR FIFO */
#define FCR_RCVRCLR 0x02 /* clear RCVR FIFO */
#define FCR_XMITCLR 0x04 /* clear XMIT FIFO */
/*
* Per PC16550D (Literature Number: SNLS378B):
*
* RXRDY, Mode 0: When in the 16450 Mode (FCR0 = 0) or in
* the FIFO Mode (FCR0 = 1, FCR3 = 0) and there is at least 1
* character in the RCVR FIFO or RCVR holding register, the
* RXRDY pin (29) will be low active. Once it is activated the
* RXRDY pin will go inactive when there are no more charac-
* ters in the FIFO or holding register.
*
* RXRDY, Mode 1: In the FIFO Mode (FCR0 = 1) when the
* FCR3 = 1 and the trigger level or the timeout has been
* reached, the RXRDY pin will go low active. Once it is acti-
* vated it will go inactive when there are no more characters
* in the FIFO or holding register.
*
* TXRDY, Mode 0: In the 16450 Mode (FCR0 = 0) or in the
* FIFO Mode (FCR0 = 1, FCR3 = 0) and there are no charac-
* ters in the XMIT FIFO or XMIT holding register, the TXRDY
* pin (24) will be low active. Once it is activated the TXRDY
* pin will go inactive after the first character is loaded into the
* XMIT FIFO or holding register.
*
* TXRDY, Mode 1: In the FIFO Mode (FCR0 = 1) when
* FCR3 = 1 and there are no characters in the XMIT FIFO, the
* TXRDY pin will go low active. This pin will become inactive
* when the XMIT FIFO is completely full.
*/
#define FCR_MODE0 0x00 /* set receiver in mode 0 */
#define FCR_MODE1 0x08 /* set receiver in mode 1 */
/* RCVR FIFO interrupt levels: trigger interrupt with this bytes in FIFO */
#define FCR_FIFO_1 0x00 /* 1 byte in RCVR FIFO */
#define FCR_FIFO_4 0x40 /* 4 bytes in RCVR FIFO */
#define FCR_FIFO_8 0x80 /* 8 bytes in RCVR FIFO */
#define FCR_FIFO_14 0xC0 /* 14 bytes in RCVR FIFO */
/* constants for line control register */
#define LCR_CS5 0x00 /* 5 bits data size */
#define LCR_CS6 0x01 /* 6 bits data size */
#define LCR_CS7 0x02 /* 7 bits data size */
#define LCR_CS8 0x03 /* 8 bits data size */
#define LCR_2_STB 0x04 /* 2 stop bits */
#define LCR_1_STB 0x00 /* 1 stop bit */
#define LCR_PEN 0x08 /* parity enable */
#define LCR_PDIS 0x00 /* parity disable */
#define LCR_EPS 0x10 /* even parity select */
#define LCR_SP 0x20 /* stick parity select */
#define LCR_SBRK 0x40 /* break control bit */
#define LCR_DLAB 0x80 /* divisor latch access enable */
/* constants for the modem control register */
#define MCR_DTR 0x01 /* dtr output */
#define MCR_RTS 0x02 /* rts output */
#define MCR_OUT1 0x04 /* output #1 */
#define MCR_OUT2 0x08 /* output #2 */
#define MCR_LOOP 0x10 /* loop back */
#define MCR_AFCE 0x20 /* auto flow control enable */
/* constants for line status register */
#define LSR_RXRDY 0x01 /* receiver data available */
#define LSR_OE 0x02 /* overrun error */
#define LSR_PE 0x04 /* parity error */
#define LSR_FE 0x08 /* framing error */
#define LSR_BI 0x10 /* break interrupt */
#define LSR_THRE 0x20 /* transmit holding register empty */
#define LSR_TEMT 0x40 /* transmitter empty */
/* constants for modem status register */
#define MSR_DCTS 0x01 /* cts change */
#define MSR_DDSR 0x02 /* dsr change */
#define MSR_DRI 0x04 /* ring change */
#define MSR_DDCD 0x08 /* data carrier change */
#define MSR_CTS 0x10 /* complement of cts */
#define MSR_DSR 0x20 /* complement of dsr */
#define MSR_RI 0x40 /* complement of ring signal */
#define MSR_DCD 0x80 /* complement of dcd */
/* convenience defines */
#define DEV_CFG(dev) \
((struct uart_device_config * const)(dev)->config->config_info)
#define DEV_DATA(dev) \
((struct uart_ns16550_dev_data_t *)(dev)->driver_data)
#define THR(dev) (DEV_CFG(dev)->port + REG_THR * UART_REG_ADDR_INTERVAL)
#define RDR(dev) (DEV_CFG(dev)->port + REG_RDR * UART_REG_ADDR_INTERVAL)
#define BRDL(dev) (DEV_CFG(dev)->port + REG_BRDL * UART_REG_ADDR_INTERVAL)
#define BRDH(dev) (DEV_CFG(dev)->port + REG_BRDH * UART_REG_ADDR_INTERVAL)
#define IER(dev) (DEV_CFG(dev)->port + REG_IER * UART_REG_ADDR_INTERVAL)
#define IIR(dev) (DEV_CFG(dev)->port + REG_IIR * UART_REG_ADDR_INTERVAL)
#define FCR(dev) (DEV_CFG(dev)->port + REG_FCR * UART_REG_ADDR_INTERVAL)
#define LCR(dev) (DEV_CFG(dev)->port + REG_LCR * UART_REG_ADDR_INTERVAL)
#define MDC(dev) (DEV_CFG(dev)->port + REG_MDC * UART_REG_ADDR_INTERVAL)
#define LSR(dev) (DEV_CFG(dev)->port + REG_LSR * UART_REG_ADDR_INTERVAL)
#define MSR(dev) (DEV_CFG(dev)->port + REG_MSR * UART_REG_ADDR_INTERVAL)
#define IIRC(dev) (DEV_DATA(dev)->iir_cache)
#if (defined(CONFIG_IA32_LEGACY_IO_PORTS) && !defined(CONFIG_NS16550_PCI))
#define INBYTE(x) sys_in8(x)
#define OUTBYTE(x, d) sys_out8(d, x)
#else
#define INBYTE(x) sys_read8(x)
#define OUTBYTE(x, d) sys_write8(d, x)
#endif /* CONFIG_IA32_LEGACY_IO_PORTS/CONFIG_NS16550_PCI */
static struct uart_driver_api ns16550_uart_driver_api;
#if defined(CONFIG_NS16550_PCI)
static inline int ns16550_pci_uart_scan(struct device *dev)
{
struct uart_device_config * const dev_cfg = DEV_CFG(dev);
pci_bus_scan_init();
if (!pci_bus_scan(&dev_cfg->pci_dev)) {
return 0;
}
#ifdef CONFIG_PCI_ENUMERATION
dev_cfg->port = dev_cfg->pci_dev.addr;
dev_cfg->irq = dev_cfg->pci_dev.irq;
#endif
pci_enable_regs(&dev_cfg->pci_dev);
return 1;
}
#else
#define ns16550_pci_uart_scan(_unused_) (1)
#endif /* CONFIG_NS16550_PCI */
/**
* @brief Initialize the chip
*
* This routine is called to reset the chip in a quiescent state.
*
* @param dev UART device struct (of type struct uart_device_config)
* @param init_info Initial configuration for UART
*
* @return N/A
*/
void ns16550_uart_port_init(struct device *dev,
const struct uart_init_info * const init_info)
{
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)) {
return;
}
dev_cfg->irq_pri = init_info->irq_pri;
dev_data->iir_cache = 0;
old_level = irq_lock();
/* calculate baud rate divisor */
divisor = (init_info->sys_clk_freq / init_info->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));
/* 8 data bits, 1 stop bit, no parity, clear DLAB */
OUTBYTE(LCR(dev), LCR_CS8 | LCR_1_STB | LCR_PDIS);
mdc = MCR_OUT2 | MCR_RTS | MCR_DTR;
if ((init_info->options & UART_OPTION_AFCE) == UART_OPTION_AFCE)
mdc |= MCR_AFCE;
OUTBYTE(MDC(dev), mdc);
/*
* Program FIFO: enabled, mode 0 (set for compatibility with quark),
* generate the interrupt at 8th byte
* Clear TX and RX FIFO
*/
OUTBYTE(FCR(dev),
FCR_FIFO | FCR_MODE0 | FCR_FIFO_8 | FCR_RCVRCLR | FCR_XMITCLR);
/* clear the port */
INBYTE(RDR(dev));
/* disable interrupts */
OUTBYTE(IER(dev), 0x00);
irq_unlock(old_level);
dev->driver_api = &ns16550_uart_driver_api;
}
/**
* @brief Poll the device for input.
*
* @param dev UART device struct (of type struct uart_device_config)
* @param c Pointer to character
*
* @return 0 if a character arrived, -1 if the input buffer if empty.
*/
static int ns16550_uart_poll_in(struct device *dev, unsigned char *c)
{
if ((INBYTE(LSR(dev)) & LSR_RXRDY) == 0x00)
return (-1);
/* got a character */
*c = INBYTE(RDR(dev));
return 0;
}
/**
* @brief Output a character in polled mode.
*
* Checks if the transmitter is empty. If empty, a character is written to
* the data register.
*
* If the hardware flow control is enabled then the handshake signal CTS has to
* be asserted in order to send a character.
*
* @param dev UART device struct (of type struct uart_device_config)
* @param c Character to send
*
* @return Sent character
*/
static unsigned char ns16550_uart_poll_out(struct device *dev,
unsigned char c)
{
/* wait for transmitter to ready to accept a character */
while ((INBYTE(LSR(dev)) & LSR_TEMT) == 0)
;
OUTBYTE(THR(dev), c);
return c;
}
#if CONFIG_UART_INTERRUPT_DRIVEN
/**
* @brief Fill FIFO with data
*
* @param dev UART device struct (of type struct uart_device_config)
* @param tx_data Data to transmit
* @param size Number of bytes to send
*
* @return Number of bytes sent
*/
static int ns16550_uart_fifo_fill(struct device *dev, const uint8_t *tx_data,
int size)
{
int i;
for (i = 0; i < size && (INBYTE(LSR(dev)) & LSR_THRE) != 0; i++) {
OUTBYTE(THR(dev), tx_data[i]);
}
return i;
}
/**
* @brief Read data from FIFO
*
* @param dev UART device struct (of type struct uart_device_config)
* @param rxData Data container
* @param size Container size
*
* @return Number of bytes read
*/
static int ns16550_uart_fifo_read(struct device *dev, uint8_t *rx_data,
const int size)
{
int i;
for (i = 0; i < size && (INBYTE(LSR(dev)) & LSR_RXRDY) != 0; i++) {
rx_data[i] = INBYTE(RDR(dev));
}
return i;
}
/**
* @brief Enable TX interrupt in IER
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void ns16550_uart_irq_tx_enable(struct device *dev)
{
OUTBYTE(IER(dev), INBYTE(IER(dev)) | IER_TBE);
}
/**
* @brief Disable TX interrupt in IER
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void ns16550_uart_irq_tx_disable(struct device *dev)
{
OUTBYTE(IER(dev), INBYTE(IER(dev)) & (~IER_TBE));
}
/**
* @brief Check if Tx IRQ has been raised
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return 1 if an IRQ is ready, 0 otherwise
*/
static int ns16550_uart_irq_tx_ready(struct device *dev)
{
return ((IIRC(dev) & IIR_ID) == IIR_THRE);
}
/**
* @brief Enable RX interrupt in IER
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void ns16550_uart_irq_rx_enable(struct device *dev)
{
OUTBYTE(IER(dev), INBYTE(IER(dev)) | IER_RXRDY);
}
/**
* @brief Disable RX interrupt in IER
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void ns16550_uart_irq_rx_disable(struct device *dev)
{
OUTBYTE(IER(dev), INBYTE(IER(dev)) & (~IER_RXRDY));
}
/**
* @brief Check if Rx IRQ has been raised
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return 1 if an IRQ is ready, 0 otherwise
*/
static int ns16550_uart_irq_rx_ready(struct device *dev)
{
return ((IIRC(dev) & IIR_ID) == IIR_RBRF);
}
/**
* @brief Enable error interrupt in IER
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void ns16550_uart_irq_err_enable(struct device *dev)
{
OUTBYTE(IER(dev), INBYTE(IER(dev)) | IER_LSR);
}
/**
* @brief Disable error interrupt in IER
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return 1 if an IRQ is ready, 0 otherwise
*/
static void ns16550_uart_irq_err_disable(struct device *dev)
{
OUTBYTE(IER(dev), INBYTE(IER(dev)) & (~IER_LSR));
}
/**
* @brief Check if any IRQ is pending
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return 1 if an IRQ is pending, 0 otherwise
*/
static int ns16550_uart_irq_is_pending(struct device *dev)
{
return (!(IIRC(dev) & IIR_IP));
}
/**
* @brief Update cached contents of IIR
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return Always 1
*/
static int ns16550_uart_irq_update(struct device *dev)
{
IIRC(dev) = INBYTE(IIR(dev));
return 1;
}
/**
* @brief Returns UART interrupt number
*
* Returns the IRQ number used by the specified UART port
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return IRQ number
*/
static unsigned int ns16550_uart_irq_get(struct device *dev)
{
return (unsigned int)DEV_CFG(dev)->irq;
}
#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
static struct uart_driver_api ns16550_uart_driver_api = {
.poll_in = ns16550_uart_poll_in,
.poll_out = ns16550_uart_poll_out,
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
.fifo_fill = ns16550_uart_fifo_fill,
.fifo_read = ns16550_uart_fifo_read,
.irq_tx_enable = ns16550_uart_irq_tx_enable,
.irq_tx_disable = ns16550_uart_irq_tx_disable,
.irq_tx_ready = ns16550_uart_irq_tx_ready,
.irq_rx_enable = ns16550_uart_irq_rx_enable,
.irq_rx_disable = ns16550_uart_irq_rx_disable,
.irq_rx_ready = ns16550_uart_irq_rx_ready,
.irq_err_enable = ns16550_uart_irq_err_enable,
.irq_err_disable = ns16550_uart_irq_err_disable,
.irq_is_pending = ns16550_uart_irq_is_pending,
.irq_update = ns16550_uart_irq_update,
.irq_get = ns16550_uart_irq_get,
#endif
};
Reference in New Issue View Git Blame Copy Permalink