+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright 2013 Tilera Corporation. All Rights Reserved.
- *
- * TILEGx UART driver.
- */
-
-#include <linux/delay.h>
-#include <linux/init.h>
-#include <linux/interrupt.h>
-#include <linux/io.h>
-#include <linux/irq.h>
-#include <linux/module.h>
-#include <linux/serial_core.h>
-#include <linux/tty.h>
-#include <linux/tty_flip.h>
-
-#include <gxio/common.h>
-#include <gxio/iorpc_globals.h>
-#include <gxio/iorpc_uart.h>
-#include <gxio/kiorpc.h>
-
-#include <hv/drv_uart_intf.h>
-
-/*
- * Use device name ttyS, major 4, minor 64-65.
- * This is the usual serial port name, 8250 conventional range.
- */
-#define TILEGX_UART_MAJOR TTY_MAJOR
-#define TILEGX_UART_MINOR 64
-#define TILEGX_UART_NAME "ttyS"
-#define DRIVER_NAME_STRING "TILEGx_Serial"
-#define TILEGX_UART_REF_CLK 125000000; /* REF_CLK is always 125 MHz. */
-
-struct tile_uart_port {
- /* UART port. */
- struct uart_port uart;
-
- /* GXIO device context. */
- gxio_uart_context_t context;
-
- /* UART access mutex. */
- struct mutex mutex;
-
- /* CPU receiving interrupts. */
- int irq_cpu;
-};
-
-static struct tile_uart_port tile_uart_ports[TILEGX_UART_NR];
-static struct uart_driver tilegx_uart_driver;
-
-
-/*
- * Read UART rx fifo, and insert the chars into tty buffer.
- */
-static void receive_chars(struct tile_uart_port *tile_uart,
- struct tty_struct *tty)
-{
- int i;
- char c;
- UART_FIFO_COUNT_t count;
- gxio_uart_context_t *context = &tile_uart->context;
- struct tty_port *port = tty->port;
-
- count.word = gxio_uart_read(context, UART_FIFO_COUNT);
- for (i = 0; i < count.rfifo_count; i++) {
- c = (char)gxio_uart_read(context, UART_RECEIVE_DATA);
- tty_insert_flip_char(port, c, TTY_NORMAL);
- }
-}
-
-
-/*
- * Drain the Rx FIFO, called by interrupt handler.
- */
-static void handle_receive(struct tile_uart_port *tile_uart)
-{
- struct tty_port *port = &tile_uart->uart.state->port;
- struct tty_struct *tty = tty_port_tty_get(port);
- gxio_uart_context_t *context = &tile_uart->context;
-
- if (!tty)
- return;
-
- /* First read UART rx fifo. */
- receive_chars(tile_uart, tty);
-
- /* Reset RFIFO_WE interrupt. */
- gxio_uart_write(context, UART_INTERRUPT_STATUS,
- UART_INTERRUPT_MASK__RFIFO_WE_MASK);
-
- /* Final read, if any chars comes between the first read and
- * the interrupt reset.
- */
- receive_chars(tile_uart, tty);
-
- spin_unlock(&tile_uart->uart.lock);
- tty_flip_buffer_push(port);
- spin_lock(&tile_uart->uart.lock);
- tty_kref_put(tty);
-}
-
-
-/*
- * Push one char to UART Write FIFO.
- * Return 0 on success, -1 if write filo is full.
- */
-static int tilegx_putchar(gxio_uart_context_t *context, char c)
-{
- UART_FLAG_t flag;
- flag.word = gxio_uart_read(context, UART_FLAG);
- if (flag.wfifo_full)
- return -1;
-
- gxio_uart_write(context, UART_TRANSMIT_DATA, (unsigned long)c);
- return 0;
-}
-
-
-/*
- * Send chars to UART Write FIFO; called by interrupt handler.
- */
-static void handle_transmit(struct tile_uart_port *tile_uart)
-{
- unsigned char ch;
- struct uart_port *port;
- struct circ_buf *xmit;
- gxio_uart_context_t *context = &tile_uart->context;
-
- /* First reset WFIFO_RE interrupt. */
- gxio_uart_write(context, UART_INTERRUPT_STATUS,
- UART_INTERRUPT_MASK__WFIFO_RE_MASK);
-
- port = &tile_uart->uart;
- xmit = &port->state->xmit;
- if (port->x_char) {
- if (tilegx_putchar(context, port->x_char))
- return;
- port->x_char = 0;
- port->icount.tx++;
- }
-
- if (uart_circ_empty(xmit) || uart_tx_stopped(port))
- return;
-
- while (!uart_circ_empty(xmit)) {
- ch = xmit->buf[xmit->tail];
- if (tilegx_putchar(context, ch))
- break;
- xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
- port->icount.tx++;
- }
-
- /* Reset WFIFO_RE interrupt. */
- gxio_uart_write(context, UART_INTERRUPT_STATUS,
- UART_INTERRUPT_MASK__WFIFO_RE_MASK);
-
- if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
- uart_write_wakeup(port);
-}
-
-
-/*
- * UART Interrupt handler.
- */
-static irqreturn_t tilegx_interrupt(int irq, void *dev_id)
-{
- unsigned long flags;
- UART_INTERRUPT_STATUS_t intr_stat;
- struct tile_uart_port *tile_uart;
- gxio_uart_context_t *context;
- struct uart_port *port = dev_id;
- irqreturn_t ret = IRQ_NONE;
-
- spin_lock_irqsave(&port->lock, flags);
-
- tile_uart = container_of(port, struct tile_uart_port, uart);
- context = &tile_uart->context;
- intr_stat.word = gxio_uart_read(context, UART_INTERRUPT_STATUS);
-
- if (intr_stat.rfifo_we) {
- handle_receive(tile_uart);
- ret = IRQ_HANDLED;
- }
- if (intr_stat.wfifo_re) {
- handle_transmit(tile_uart);
- ret = IRQ_HANDLED;
- }
-
- spin_unlock_irqrestore(&port->lock, flags);
- return ret;
-}
-
-
-/*
- * Return TIOCSER_TEMT when transmitter FIFO is empty.
- */
-static u_int tilegx_tx_empty(struct uart_port *port)
-{
- int ret;
- UART_FLAG_t flag;
- struct tile_uart_port *tile_uart;
- gxio_uart_context_t *context;
-
- tile_uart = container_of(port, struct tile_uart_port, uart);
- if (!mutex_trylock(&tile_uart->mutex))
- return 0;
- context = &tile_uart->context;
-
- flag.word = gxio_uart_read(context, UART_FLAG);
- ret = (flag.wfifo_empty) ? TIOCSER_TEMT : 0;
- mutex_unlock(&tile_uart->mutex);
-
- return ret;
-}
-
-
-/*
- * Set state of the modem control output lines.
- */
-static void tilegx_set_mctrl(struct uart_port *port, u_int mctrl)
-{
- /* N/A */
-}
-
-
-/*
- * Get state of the modem control input lines.
- */
-static u_int tilegx_get_mctrl(struct uart_port *port)
-{
- return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
-}
-
-
-/*
- * Stop transmitting.
- */
-static void tilegx_stop_tx(struct uart_port *port)
-{
- /* N/A */
-}
-
-
-/*
- * Start transmitting.
- */
-static void tilegx_start_tx(struct uart_port *port)
-{
- unsigned char ch;
- struct circ_buf *xmit;
- struct tile_uart_port *tile_uart;
- gxio_uart_context_t *context;
-
- tile_uart = container_of(port, struct tile_uart_port, uart);
- if (!mutex_trylock(&tile_uart->mutex))
- return;
- context = &tile_uart->context;
- xmit = &port->state->xmit;
- if (port->x_char) {
- if (tilegx_putchar(context, port->x_char))
- return;
- port->x_char = 0;
- port->icount.tx++;
- }
-
- if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
- mutex_unlock(&tile_uart->mutex);
- return;
- }
-
- while (!uart_circ_empty(xmit)) {
- ch = xmit->buf[xmit->tail];
- if (tilegx_putchar(context, ch))
- break;
- xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
- port->icount.tx++;
- }
-
- if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
- uart_write_wakeup(port);
-
- mutex_unlock(&tile_uart->mutex);
-}
-
-
-/*
- * Stop receiving - port is in process of being closed.
- */
-static void tilegx_stop_rx(struct uart_port *port)
-{
- int err;
- struct tile_uart_port *tile_uart;
- gxio_uart_context_t *context;
- int cpu;
-
- tile_uart = container_of(port, struct tile_uart_port, uart);
- if (!mutex_trylock(&tile_uart->mutex))
- return;
-
- context = &tile_uart->context;
- cpu = tile_uart->irq_cpu;
- err = gxio_uart_cfg_interrupt(context, cpu_x(cpu), cpu_y(cpu),
- KERNEL_PL, -1);
- mutex_unlock(&tile_uart->mutex);
-}
-
-/*
- * Control the transmission of a break signal.
- */
-static void tilegx_break_ctl(struct uart_port *port, int break_state)
-{
- /* N/A */
-}
-
-
-/*
- * Perform initialization and enable port for reception.
- */
-static int tilegx_startup(struct uart_port *port)
-{
- struct tile_uart_port *tile_uart;
- gxio_uart_context_t *context;
- int ret = 0;
- int cpu = raw_smp_processor_id(); /* pick an arbitrary cpu */
-
- tile_uart = container_of(port, struct tile_uart_port, uart);
- if (mutex_lock_interruptible(&tile_uart->mutex))
- return -EBUSY;
- context = &tile_uart->context;
-
- /* Now open the hypervisor device if we haven't already. */
- if (context->fd < 0) {
- UART_INTERRUPT_MASK_t intr_mask;
-
- /* Initialize UART device. */
- ret = gxio_uart_init(context, port->line);
- if (ret) {
- ret = -ENXIO;
- goto err;
- }
-
- /* Create our IRQs. */
- port->irq = irq_alloc_hwirq(-1);
- if (!port->irq)
- goto err_uart_dest;
- tile_irq_activate(port->irq, TILE_IRQ_PERCPU);
-
- /* Register our IRQs. */
- ret = request_irq(port->irq, tilegx_interrupt, 0,
- tilegx_uart_driver.driver_name, port);
- if (ret)
- goto err_dest_irq;
-
- /* Request that the hardware start sending us interrupts. */
- tile_uart->irq_cpu = cpu;
- ret = gxio_uart_cfg_interrupt(context, cpu_x(cpu), cpu_y(cpu),
- KERNEL_PL, port->irq);
- if (ret)
- goto err_free_irq;
-
- /* Enable UART Tx/Rx Interrupt. */
- intr_mask.word = gxio_uart_read(context, UART_INTERRUPT_MASK);
- intr_mask.wfifo_re = 0;
- intr_mask.rfifo_we = 0;
- gxio_uart_write(context, UART_INTERRUPT_MASK, intr_mask.word);
-
- /* Reset the Tx/Rx interrupt in case it's set. */
- gxio_uart_write(context, UART_INTERRUPT_STATUS,
- UART_INTERRUPT_MASK__WFIFO_RE_MASK |
- UART_INTERRUPT_MASK__RFIFO_WE_MASK);
- }
-
- mutex_unlock(&tile_uart->mutex);
- return ret;
-
-err_free_irq:
- free_irq(port->irq, port);
-err_dest_irq:
- irq_free_hwirq(port->irq);
-err_uart_dest:
- gxio_uart_destroy(context);
- ret = -ENXIO;
-err:
- mutex_unlock(&tile_uart->mutex);
- return ret;
-}
-
-
-/*
- * Release kernel resources if it is the last close, disable the port,
- * free IRQ and close the port.
- */
-static void tilegx_shutdown(struct uart_port *port)
-{
- int err;
- UART_INTERRUPT_MASK_t intr_mask;
- struct tile_uart_port *tile_uart;
- gxio_uart_context_t *context;
- int cpu;
-
- tile_uart = container_of(port, struct tile_uart_port, uart);
- if (mutex_lock_interruptible(&tile_uart->mutex))
- return;
- context = &tile_uart->context;
-
- /* Disable UART Tx/Rx Interrupt. */
- intr_mask.word = gxio_uart_read(context, UART_INTERRUPT_MASK);
- intr_mask.wfifo_re = 1;
- intr_mask.rfifo_we = 1;
- gxio_uart_write(context, UART_INTERRUPT_MASK, intr_mask.word);
-
- /* Request that the hardware stop sending us interrupts. */
- cpu = tile_uart->irq_cpu;
- err = gxio_uart_cfg_interrupt(context, cpu_x(cpu), cpu_y(cpu),
- KERNEL_PL, -1);
-
- if (port->irq > 0) {
- free_irq(port->irq, port);
- irq_free_hwirq(port->irq);
- port->irq = 0;
- }
-
- gxio_uart_destroy(context);
-
- mutex_unlock(&tile_uart->mutex);
-}
-
-
-/*
- * Flush the buffer.
- */
-static void tilegx_flush_buffer(struct uart_port *port)
-{
- /* N/A */
-}
-
-
-/*
- * Change the port parameters.
- */
-static void tilegx_set_termios(struct uart_port *port,
- struct ktermios *termios, struct ktermios *old)
-{
- int err;
- UART_DIVISOR_t divisor;
- UART_TYPE_t type;
- unsigned int baud;
- struct tile_uart_port *tile_uart;
- gxio_uart_context_t *context;
-
- tile_uart = container_of(port, struct tile_uart_port, uart);
- if (!mutex_trylock(&tile_uart->mutex))
- return;
- context = &tile_uart->context;
-
- /* Open the hypervisor device if we haven't already. */
- if (context->fd < 0) {
- err = gxio_uart_init(context, port->line);
- if (err) {
- mutex_unlock(&tile_uart->mutex);
- return;
- }
- }
-
- divisor.word = gxio_uart_read(context, UART_DIVISOR);
- type.word = gxio_uart_read(context, UART_TYPE);
-
- /* Divisor. */
- baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
- divisor.divisor = uart_get_divisor(port, baud);
-
- /* Byte size. */
- if ((termios->c_cflag & CSIZE) == CS7)
- type.dbits = UART_TYPE__DBITS_VAL_SEVEN_DBITS;
- else
- type.dbits = UART_TYPE__DBITS_VAL_EIGHT_DBITS;
-
- /* Parity. */
- if (termios->c_cflag & PARENB) {
- /* Mark or Space parity. */
- if (termios->c_cflag & CMSPAR)
- if (termios->c_cflag & PARODD)
- type.ptype = UART_TYPE__PTYPE_VAL_MARK;
- else
- type.ptype = UART_TYPE__PTYPE_VAL_SPACE;
- else if (termios->c_cflag & PARODD)
- type.ptype = UART_TYPE__PTYPE_VAL_ODD;
- else
- type.ptype = UART_TYPE__PTYPE_VAL_EVEN;
- } else
- type.ptype = UART_TYPE__PTYPE_VAL_NONE;
-
- /* Stop bits. */
- if (termios->c_cflag & CSTOPB)
- type.sbits = UART_TYPE__SBITS_VAL_TWO_SBITS;
- else
- type.sbits = UART_TYPE__SBITS_VAL_ONE_SBITS;
-
- /* Set the uart paramters. */
- gxio_uart_write(context, UART_DIVISOR, divisor.word);
- gxio_uart_write(context, UART_TYPE, type.word);
-
- mutex_unlock(&tile_uart->mutex);
-}
-
-
-/*
- * Return string describing the specified port.
- */
-static const char *tilegx_type(struct uart_port *port)
-{
- return port->type == PORT_TILEGX ? DRIVER_NAME_STRING : NULL;
-}
-
-
-/*
- * Release the resources being used by 'port'.
- */
-static void tilegx_release_port(struct uart_port *port)
-{
- /* Nothing to release. */
-}
-
-
-/*
- * Request the resources being used by 'port'.
- */
-static int tilegx_request_port(struct uart_port *port)
-{
- /* Always present. */
- return 0;
-}
-
-
-/*
- * Configure/autoconfigure the port.
- */
-static void tilegx_config_port(struct uart_port *port, int flags)
-{
- if (flags & UART_CONFIG_TYPE)
- port->type = PORT_TILEGX;
-}
-
-
-/*
- * Verify the new serial_struct (for TIOCSSERIAL).
- */
-static int tilegx_verify_port(struct uart_port *port,
- struct serial_struct *ser)
-{
- if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_TILEGX))
- return -EINVAL;
-
- return 0;
-}
-
-#ifdef CONFIG_CONSOLE_POLL
-
-/*
- * Console polling routines for writing and reading from the uart while
- * in an interrupt or debug context.
- */
-
-static int tilegx_poll_get_char(struct uart_port *port)
-{
- UART_FIFO_COUNT_t count;
- gxio_uart_context_t *context;
- struct tile_uart_port *tile_uart;
-
- tile_uart = container_of(port, struct tile_uart_port, uart);
- context = &tile_uart->context;
- count.word = gxio_uart_read(context, UART_FIFO_COUNT);
- if (count.rfifo_count == 0)
- return NO_POLL_CHAR;
- return (char)gxio_uart_read(context, UART_RECEIVE_DATA);
-}
-
-static void tilegx_poll_put_char(struct uart_port *port, unsigned char c)
-{
- gxio_uart_context_t *context;
- struct tile_uart_port *tile_uart;
-
- tile_uart = container_of(port, struct tile_uart_port, uart);
- context = &tile_uart->context;
- gxio_uart_write(context, UART_TRANSMIT_DATA, (unsigned long)c);
-}
-
-#endif /* CONFIG_CONSOLE_POLL */
-
-
-static const struct uart_ops tilegx_ops = {
- .tx_empty = tilegx_tx_empty,
- .set_mctrl = tilegx_set_mctrl,
- .get_mctrl = tilegx_get_mctrl,
- .stop_tx = tilegx_stop_tx,
- .start_tx = tilegx_start_tx,
- .stop_rx = tilegx_stop_rx,
- .break_ctl = tilegx_break_ctl,
- .startup = tilegx_startup,
- .shutdown = tilegx_shutdown,
- .flush_buffer = tilegx_flush_buffer,
- .set_termios = tilegx_set_termios,
- .type = tilegx_type,
- .release_port = tilegx_release_port,
- .request_port = tilegx_request_port,
- .config_port = tilegx_config_port,
- .verify_port = tilegx_verify_port,
-#ifdef CONFIG_CONSOLE_POLL
- .poll_get_char = tilegx_poll_get_char,
- .poll_put_char = tilegx_poll_put_char,
-#endif
-};
-
-
-static void tilegx_init_ports(void)
-{
- int i;
- struct uart_port *port;
-
- for (i = 0; i < TILEGX_UART_NR; i++) {
- port = &tile_uart_ports[i].uart;
- port->ops = &tilegx_ops;
- port->line = i;
- port->type = PORT_TILEGX;
- port->uartclk = TILEGX_UART_REF_CLK;
- port->flags = UPF_BOOT_AUTOCONF;
-
- tile_uart_ports[i].context.fd = -1;
- mutex_init(&tile_uart_ports[i].mutex);
- }
-}
-
-
-static struct uart_driver tilegx_uart_driver = {
- .owner = THIS_MODULE,
- .driver_name = DRIVER_NAME_STRING,
- .dev_name = TILEGX_UART_NAME,
- .major = TILEGX_UART_MAJOR,
- .minor = TILEGX_UART_MINOR,
- .nr = TILEGX_UART_NR,
-};
-
-
-static int __init tilegx_init(void)
-{
- int i;
- int ret;
- struct tty_driver *tty_drv;
-
- ret = uart_register_driver(&tilegx_uart_driver);
- if (ret)
- return ret;
- tty_drv = tilegx_uart_driver.tty_driver;
- tty_drv->init_termios.c_cflag = B115200 | CS8 | CREAD | HUPCL | CLOCAL;
- tty_drv->init_termios.c_ispeed = 115200;
- tty_drv->init_termios.c_ospeed = 115200;
-
- tilegx_init_ports();
-
- for (i = 0; i < TILEGX_UART_NR; i++) {
- struct uart_port *port = &tile_uart_ports[i].uart;
- ret = uart_add_one_port(&tilegx_uart_driver, port);
- }
-
- return 0;
-}
-
-
-static void __exit tilegx_exit(void)
-{
- int i;
- struct uart_port *port;
-
- for (i = 0; i < TILEGX_UART_NR; i++) {
- port = &tile_uart_ports[i].uart;
- uart_remove_one_port(&tilegx_uart_driver, port);
- }
-
- uart_unregister_driver(&tilegx_uart_driver);
-}
-
-
-module_init(tilegx_init);
-module_exit(tilegx_exit);
-
-MODULE_AUTHOR("Tilera Corporation");
-MODULE_DESCRIPTION("TILEGx serial port driver");
-MODULE_LICENSE("GPL");
projects / linux-block.git / commitdiff