nuttx/arch/risc-v/src/c906/c906_serial.c

742 lines
20 KiB
C

/****************************************************************************
* arch/risc-v/src/c906/c906_serial.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/serial/serial.h>
#include <arch/board/board.h>
#include "riscv_internal.h"
#include "c906_config.h"
#include "chip.h"
#include "c906.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* If we are not using the serial driver for the console, then we still must
* provide some minimal implementation of up_putc.
*/
#ifdef USE_SERIALDRIVER
/* Which UART with be tty0/console and which tty1? The console will always
* be ttyS0. If there is no console then will use the lowest numbered UART.
*/
#ifdef HAVE_SERIAL_CONSOLE
# if defined(CONFIG_UART0_SERIAL_CONSOLE)
# define CONSOLE_DEV g_uart0port /* UART0 is console */
# define TTYS0_DEV g_uart0port /* UART0 is ttyS0 */
# undef TTYS1_DEV /* No ttyS1 */
# define SERIAL_CONSOLE 1
# else
# error "I'm confused... Do we have a serial console or not?"
# endif
#else
# undef CONSOLE_DEV /* No console */
# undef CONFIG_UART0_SERIAL_CONSOLE
# if defined(CONFIG_C906_UART0)
# define TTYS0_DEV g_uart0port /* UART0 is ttyS0 */
# undef TTYS1_DEV /* No ttyS1 */
# define SERIAL_CONSOLE 1
# else
# undef TTYS0_DEV
# undef TTYS1_DEV
# endif
#endif
/* Common initialization logic will not not know that the all of the UARTs
* have been disabled. So, as a result, we may still have to provide
* stub implementations of riscv_earlyserialinit(), riscv_serialinit(), and
* up_putc().
*/
#ifdef HAVE_UART_DEVICE
/****************************************************************************
* Private Types
****************************************************************************/
struct up_dev_s
{
uintptr_t uartbase; /* Base address of UART registers */
uint32_t baud; /* Configured baud */
uint8_t irq; /* IRQ associated with this UART */
uint8_t im; /* Interrupt mask state */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Low-level helpers */
static uint32_t up_serialin(struct up_dev_s *priv, int offset);
static void up_serialout(struct up_dev_s *priv, int offset, uint32_t value);
static void up_restoreuartint(struct up_dev_s *priv, uint8_t im);
static void up_disableuartint(struct up_dev_s *priv, uint8_t *im);
/* Serial driver methods */
static int up_setup(struct uart_dev_s *dev);
static void up_shutdown(struct uart_dev_s *dev);
static int up_attach(struct uart_dev_s *dev);
static void up_detach(struct uart_dev_s *dev);
static int up_interrupt(int irq, void *context, void *arg);
static int up_ioctl(struct file *filep, int cmd, unsigned long arg);
static int up_receive(struct uart_dev_s *dev, uint32_t *status);
static void up_rxint(struct uart_dev_s *dev, bool enable);
static bool up_rxavailable(struct uart_dev_s *dev);
static void up_send(struct uart_dev_s *dev, int ch);
static void up_txint(struct uart_dev_s *dev, bool enable);
static bool up_txready(struct uart_dev_s *dev);
static bool up_txempty(struct uart_dev_s *dev);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct uart_ops_s g_uart_ops =
{
.setup = up_setup,
.shutdown = up_shutdown,
.attach = up_attach,
.detach = up_detach,
.ioctl = up_ioctl,
.receive = up_receive,
.rxint = up_rxint,
.rxavailable = up_rxavailable,
#ifdef CONFIG_SERIAL_IFLOWCONTROL
.rxflowcontrol = NULL,
#endif
.send = up_send,
.txint = up_txint,
.txready = up_txready,
.txempty = up_txempty,
};
/* I/O buffers */
#ifdef CONFIG_C906_UART0
static char g_uart0rxbuffer[CONFIG_UART0_RXBUFSIZE];
static char g_uart0txbuffer[CONFIG_UART0_TXBUFSIZE];
static uint32_t g_rxdata;
#endif
#ifdef CONFIG_C906_UART0
static struct up_dev_s g_uart0priv =
{
.uartbase = C906_UART0_BASE,
.baud = CONFIG_UART0_BAUD,
.irq = C906_IRQ_UART0,
};
static uart_dev_t g_uart0port =
{
#if SERIAL_CONSOLE == 1
.isconsole = 1,
#endif
.recv =
{
.size = CONFIG_UART0_RXBUFSIZE,
.buffer = g_uart0rxbuffer,
},
.xmit =
{
.size = CONFIG_UART0_TXBUFSIZE,
.buffer = g_uart0txbuffer,
},
.ops = &g_uart_ops,
.priv = &g_uart0priv,
};
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: up_serialin
****************************************************************************/
static uint32_t up_serialin(struct up_dev_s *priv, int offset)
{
return getreg32(priv->uartbase + offset);
}
/****************************************************************************
* Name: up_serialout
****************************************************************************/
static void up_serialout(struct up_dev_s *priv, int offset, uint32_t value)
{
putreg32(value, priv->uartbase + offset);
}
/****************************************************************************
* Name: up_restoreuartint
****************************************************************************/
static void up_restoreuartint(struct up_dev_s *priv, uint8_t im)
{
irqstate_t flags = enter_critical_section();
priv->im = im;
up_serialout(priv, UART_IE_OFFSET, im);
leave_critical_section(flags);
}
/****************************************************************************
* Name: up_disableuartint
****************************************************************************/
static void up_disableuartint(struct up_dev_s *priv, uint8_t *im)
{
irqstate_t flags = enter_critical_section();
/* Return the current interrupt mask value */
if (im)
{
*im = priv->im;
}
/* Disable all interrupts */
priv->im = 0;
up_serialout(priv, UART_IE_OFFSET, 0);
leave_critical_section(flags);
}
/****************************************************************************
* Name: up_setup
*
* Description:
* Configure the UART baud, bits, parity, etc. This method is called the
* first time that the serial port is opened.
*
****************************************************************************/
static int up_setup(struct uart_dev_s *dev)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
/* Enable RX */
up_serialout(priv, UART_RXCTL_OFFSET,
IER_RDA_INT_ENABLE | IIR_RECV_LINE_ENABLE);
/* nothing to be done for QEMU */
return OK;
}
/****************************************************************************
* Name: up_shutdown
*
* Description:
* Disable the UART. This method is called when the serial
* port is closed
*
****************************************************************************/
static void up_shutdown(struct uart_dev_s *dev)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
/* Disable interrupts */
up_disableuartint(priv, NULL);
}
/****************************************************************************
* Name: up_attach
*
* Description:
* Configure the UART to operation in interrupt driven mode. This method is
* called when the serial port is opened. Normally, this is just after the
* the setup() method is called, however, the serial console may operate in
* a non-interrupt driven mode during the boot phase.
*
* RX and TX interrupts are not enabled by the attach method (unless the
* hardware supports multiple levels of interrupt enabling). The RX and TX
* interrupts are not enabled until the txint() and rxint() are called.
*
****************************************************************************/
static int up_attach(struct uart_dev_s *dev)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
int ret;
/* Initialize interrupt generation on the peripheral */
up_serialout(priv, UART_IE_OFFSET,
IER_RDA_INT_ENABLE | IER_THRE_INT_ENABLE);
ret = irq_attach(priv->irq, up_interrupt, dev);
if (ret == OK)
{
/* Enable the interrupt (RX and TX interrupts are still disabled
* in the UART
*/
up_enable_irq(priv->irq);
}
return ret;
}
/****************************************************************************
* Name: up_detach
*
* Description:
* Detach UART interrupts. This method is called when the serial port is
* closed normally just before the shutdown method is called. The exception
* is the serial console which is never shutdown.
*
****************************************************************************/
static void up_detach(struct uart_dev_s *dev)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
/* Disable interrupts */
up_disable_irq(priv->irq);
/* Detach from the interrupt */
irq_detach(priv->irq);
}
/****************************************************************************
* Name: up_interrupt
*
* Description:
* This is the UART interrupt handler. It will be invoked when an
* interrupt is received on the 'irq'. It should call uart_xmitchars or
* uart_recvchars to perform the appropriate data transfers. The
* interrupt handling logic must be able to map the 'arg' to the
* appropriate uart_dev_s structure in order to call these functions.
*
****************************************************************************/
/* TODO: why no data ready flag LSR_DATA_READY in LSR under QEMU ??? */
#ifdef CONFIG_C906_WITH_QEMU
static volatile uint32_t lsr_data_ready = 0;
#endif
static int up_interrupt(int irq, void *context, void *arg)
{
struct uart_dev_s *dev = (struct uart_dev_s *)arg;
struct up_dev_s *priv;
uint32_t status;
int passes;
DEBUGASSERT(dev != NULL && dev->priv != NULL);
priv = (struct up_dev_s *)dev->priv;
/* Loop until there are no characters to be transferred or,
* until we have been looping for a long time.
*/
for (passes = 0; passes < 256; passes++)
{
/* Retrieve interrupt pending status */
status = up_serialin(priv, UART_IIR_OFFSET);
if (status == 0)
{
break;
}
if (status & DW_IIR_RECV_DATA)
{
/* Process incoming bytes */
#ifdef CONFIG_C906_WITH_QEMU
lsr_data_ready = 1;
#endif
uart_recvchars(dev);
}
if (status & DW_IIR_THR_EMPTY)
{
/* Process outgoing bytes */
uart_xmitchars(dev);
}
}
return OK;
}
/****************************************************************************
* Name: up_ioctl
*
* Description:
* All ioctl calls will be routed through this method
*
****************************************************************************/
static int up_ioctl(struct file *filep, int cmd, unsigned long arg)
{
return -ENOTTY;
}
/****************************************************************************
* Name: up_receive
*
* Description:
* Called (usually) from the interrupt level to receive one
* character from the UART. Error bits associated with the
* receipt are provided in the return 'status'.
*
****************************************************************************/
static int up_receive(struct uart_dev_s *dev, uint32_t *status)
{
/* Return status information */
if (status)
{
*status = 0; /* We are not yet tracking serial errors */
}
/* Return cached data */
return g_rxdata;
}
/****************************************************************************
* Name: up_rxint
*
* Description:
* Call to enable or disable RX interrupts
*
****************************************************************************/
static void up_rxint(struct uart_dev_s *dev, bool enable)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
irqstate_t flags = enter_critical_section();
if (enable)
{
#ifndef CONFIG_SUPPRESS_SERIAL_INTS
priv->im |= IER_RDA_INT_ENABLE;
#endif
}
else
{
priv->im &= ~IER_RDA_INT_ENABLE;
}
up_serialout(priv, UART_IE_OFFSET, priv->im);
leave_critical_section(flags);
}
/****************************************************************************
* Name: up_rxavailable
*
* Description:
* Return true if the receive register is not empty
*
****************************************************************************/
static bool up_rxavailable(struct uart_dev_s *dev)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
uint32_t dr = 0;
/* Return true is data is available in the receive data buffer */
uint32_t rxdata = up_serialin(priv, UART_RXDATA_OFFSET);
g_rxdata = rxdata & 0xff;
#ifdef CONFIG_C906_WITH_QEMU
dr = lsr_data_ready;
lsr_data_ready = 0;
#else
dr = up_serialin(priv, UART_LSR_OFFSET) & LSR_DATA_READY;
#endif
return !!dr;
}
/****************************************************************************
* Name: up_send
*
* Description:
* This method will send one byte on the UART.
*
****************************************************************************/
static void up_send(struct uart_dev_s *dev, int ch)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
up_serialout(priv, UART_TXDATA_OFFSET, (uint32_t)ch);
}
/****************************************************************************
* Name: up_txint
*
* Description:
* Call to enable or disable TX interrupts
*
****************************************************************************/
static void up_txint(struct uart_dev_s *dev, bool enable)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
irqstate_t flags;
flags = enter_critical_section();
if (enable)
{
/* Enable the TX interrupt */
#ifndef CONFIG_SUPPRESS_SERIAL_INTS
priv->im |= IER_THRE_INT_ENABLE;
up_serialout(priv, UART_IE_OFFSET, priv->im);
/* Fake a TX interrupt here by just calling uart_xmitchars() with
* interrupts disabled (note this may recurse).
*/
uart_xmitchars(dev);
#endif
}
else
{
/* Disable the TX interrupt */
priv->im &= ~IER_THRE_INT_ENABLE;
up_serialout(priv, UART_IE_OFFSET, priv->im);
}
leave_critical_section(flags);
}
/****************************************************************************
* Name: up_txready
*
* Description:
* Return true if the tranmsit data register is not full
*
****************************************************************************/
static bool up_txready(struct uart_dev_s *dev)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
/* Return TRUE if the TX FIFO is not full */
return !!(up_serialin(priv, UART_LSR_OFFSET) & DW_LSR_TRANS_EMPTY);
}
/****************************************************************************
* Name: up_txempty
*
* Description:
* Return true if the tranmsit data register is empty
*
****************************************************************************/
static bool up_txempty(struct uart_dev_s *dev)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
/* Return TRUE if the TX wartermak is pending */
return !!(up_serialin(priv, UART_LSR_OFFSET) & DW_LSR_TRANS_EMPTY);
}
/****************************************************************************
* Public Functions
****************************************************************************/
#ifdef USE_EARLYSERIALINIT
/****************************************************************************
* Name: riscv_earlyserialinit
*
* Description:
* Performs the low level UART initialization early in debug so that the
* serial console will be available during bootup. This must be called
* before riscv_serialinit. NOTE: This function depends on GPIO pin
* configuration performed in up_consoleinit() and main clock iniialization
* performed in up_clkinitialize().
*
****************************************************************************/
void riscv_earlyserialinit(void)
{
/* Disable interrupts from all UARTS. The console is enabled in
* c906_consoleinit().
*/
up_disableuartint(TTYS0_DEV.priv, NULL);
#ifdef TTYS1_DEV
up_disableuartint(TTYS1_DEV.priv, NULL);
#endif
/* Configuration whichever one is the console */
#ifdef HAVE_SERIAL_CONSOLE
CONSOLE_DEV.isconsole = true;
up_setup(&CONSOLE_DEV);
#endif
}
#endif
/****************************************************************************
* Name: riscv_serialinit
*
* Description:
* Register serial console and serial ports. This assumes
* that riscv_earlyserialinit was called previously.
*
****************************************************************************/
void riscv_serialinit(void)
{
/* Register the console */
#ifdef HAVE_SERIAL_CONSOLE
uart_register("/dev/console", &CONSOLE_DEV);
#endif
/* Register all UARTs */
uart_register("/dev/ttyS0", &TTYS0_DEV);
#ifdef TTYS1_DEV
uart_register("/dev/ttyS1", &TTYS1_DEV);
#endif
}
/****************************************************************************
* Name: up_putc
*
* Description:
* Provide priority, low-level access to support OS debug writes
*
****************************************************************************/
int up_putc(int ch)
{
#ifdef HAVE_SERIAL_CONSOLE
struct up_dev_s *priv = (struct up_dev_s *)CONSOLE_DEV.priv;
uint8_t imr;
up_disableuartint(priv, &imr);
/* Check for LF */
if (ch == '\n')
{
/* Add CR */
riscv_lowputc('\r');
}
riscv_lowputc(ch);
up_restoreuartint(priv, imr);
#endif
return ch;
}
/****************************************************************************
* Name: riscv_earlyserialinit, riscv_serialinit, and up_putc
*
* Description:
* stubs that may be needed. These stubs would be used if all UARTs are
* disabled. In that case, the logic in common/up_initialize() is not
* smart enough to know that there are not UARTs and will still expect
* these interfaces to be provided.
*
****************************************************************************/
#else /* HAVE_UART_DEVICE */
void riscv_earlyserialinit(void)
{
}
void riscv_serialinit(void)
{
}
int up_putc(int ch)
{
return ch;
}
#endif /* HAVE_UART_DEVICE */
#else /* USE_SERIALDRIVER */
/****************************************************************************
* Name: up_putc
*
* Description:
* Provide priority, low-level access to support OS debug writes
*
****************************************************************************/
int up_putc(int ch)
{
#ifdef HAVE_SERIAL_CONSOLE
/* Check for LF */
if (ch == '\n')
{
/* Add CR */
riscv_lowputc('\r');
}
riscv_lowputc(ch);
#endif
return ch;
}
#endif /* USE_SERIALDRIVER */