Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
/*
 *  Driver for GRLIB serial ports (APBUART)
 *
 *  Based on linux/drivers/serial/amba.c
 *
 *  Copyright (C) 2000 Deep Blue Solutions Ltd.
 *  Copyright (C) 2003 Konrad Eisele <eiselekd@web.de>
 *  Copyright (C) 2006 Daniel Hellstrom <daniel@gaisler.com>, Aeroflex Gaisler AB
 *  Copyright (C) 2008 Gilead Kutnick <kutnickg@zin-tech.com>
 *  Copyright (C) 2009 Kristoffer Glembo <kristoffer@gaisler.com>, Aeroflex Gaisler AB
 */
 
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/kthread.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/serial_core.h>
#include <asm/irq.h>
 
#include "apbuart.h"
 
#define SERIAL_APBUART_MAJOR	TTY_MAJOR
#define SERIAL_APBUART_MINOR	64
#define UART_DUMMY_RSR_RX	0x8000	/* for ignore all read */
 
static void apbuart_tx_chars(struct uart_port *port);
 
static void apbuart_stop_tx(struct uart_port *port)
{
<------>unsigned int cr;
 
<------>cr = UART_GET_CTRL(port);
<------>cr &= ~UART_CTRL_TI;
<------>UART_PUT_CTRL(port, cr);
}
 
static void apbuart_start_tx(struct uart_port *port)
{
<------>unsigned int cr;
 
<------>cr = UART_GET_CTRL(port);
<------>cr |= UART_CTRL_TI;
<------>UART_PUT_CTRL(port, cr);
 
<------>if (UART_GET_STATUS(port) & UART_STATUS_THE)
<------><------>apbuart_tx_chars(port);
}
 
static void apbuart_stop_rx(struct uart_port *port)
{
<------>unsigned int cr;
 
<------>cr = UART_GET_CTRL(port);
<------>cr &= ~(UART_CTRL_RI);
<------>UART_PUT_CTRL(port, cr);
}
 
static void apbuart_rx_chars(struct uart_port *port)
{
<------>unsigned int status, ch, rsr, flag;
<------>unsigned int max_chars = port->fifosize;
 
<------>status = UART_GET_STATUS(port);
 
<------>while (UART_RX_DATA(status) && (max_chars--)) {
 
<------><------>ch = UART_GET_CHAR(port);
<------><------>flag = TTY_NORMAL;
 
<------><------>port->icount.rx++;
 
<------><------>rsr = UART_GET_STATUS(port) | UART_DUMMY_RSR_RX;
<------><------>UART_PUT_STATUS(port, 0);
<------><------>if (rsr & UART_STATUS_ERR) {
 
<------><------><------>if (rsr & UART_STATUS_BR) {
<------><------><------><------>rsr &= ~(UART_STATUS_FE | UART_STATUS_PE);
<------><------><------><------>port->icount.brk++;
<------><------><------><------>if (uart_handle_break(port))
<------><------><------><------><------>goto ignore_char;
<------><------><------>} else if (rsr & UART_STATUS_PE) {
<------><------><------><------>port->icount.parity++;
<------><------><------>} else if (rsr & UART_STATUS_FE) {
<------><------><------><------>port->icount.frame++;
<------><------><------>}
<------><------><------>if (rsr & UART_STATUS_OE)
<------><------><------><------>port->icount.overrun++;
 
<------><------><------>rsr &= port->read_status_mask;
 
<------><------><------>if (rsr & UART_STATUS_PE)
<------><------><------><------>flag = TTY_PARITY;
<------><------><------>else if (rsr & UART_STATUS_FE)
<------><------><------><------>flag = TTY_FRAME;
<------><------>}
 
<------><------>if (uart_handle_sysrq_char(port, ch))
<------><------><------>goto ignore_char;
 
<------><------>uart_insert_char(port, rsr, UART_STATUS_OE, ch, flag);
 
 
<------>      ignore_char:
<------><------>status = UART_GET_STATUS(port);
<------>}
 
<------>spin_unlock(&port->lock);
<------>tty_flip_buffer_push(&port->state->port);
<------>spin_lock(&port->lock);
}
 
static void apbuart_tx_chars(struct uart_port *port)
{
<------>struct circ_buf *xmit = &port->state->xmit;
<------>int count;
 
<------>if (port->x_char) {
<------><------>UART_PUT_CHAR(port, port->x_char);
<------><------>port->icount.tx++;
<------><------>port->x_char = 0;
<------><------>return;
<------>}
 
<------>if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
<------><------>apbuart_stop_tx(port);
<------><------>return;
<------>}
 
<------>/* amba: fill FIFO */
<------>count = port->fifosize >> 1;
<------>do {
<------><------>UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
<------><------>xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
<------><------>port->icount.tx++;
<------><------>if (uart_circ_empty(xmit))
<------><------><------>break;
<------>} while (--count > 0);
 
<------>if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
<------><------>uart_write_wakeup(port);
 
<------>if (uart_circ_empty(xmit))
<------><------>apbuart_stop_tx(port);
}
 
static irqreturn_t apbuart_int(int irq, void *dev_id)
{
<------>struct uart_port *port = dev_id;
<------>unsigned int status;
 
<------>spin_lock(&port->lock);
 
<------>status = UART_GET_STATUS(port);
<------>if (status & UART_STATUS_DR)
<------><------>apbuart_rx_chars(port);
<------>if (status & UART_STATUS_THE)
<------><------>apbuart_tx_chars(port);
 
<------>spin_unlock(&port->lock);
 
<------>return IRQ_HANDLED;
}
 
static unsigned int apbuart_tx_empty(struct uart_port *port)
{
<------>unsigned int status = UART_GET_STATUS(port);
<------>return status & UART_STATUS_THE ? TIOCSER_TEMT : 0;
}
 
static unsigned int apbuart_get_mctrl(struct uart_port *port)
{
<------>/* The GRLIB APBUART handles flow control in hardware */
<------>return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
}
 
static void apbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
<------>/* The GRLIB APBUART handles flow control in hardware */
}
 
static void apbuart_break_ctl(struct uart_port *port, int break_state)
{
<------>/* We don't support sending break */
}
 
static int apbuart_startup(struct uart_port *port)
{
<------>int retval;
<------>unsigned int cr;
 
<------>/* Allocate the IRQ */
<------>retval = request_irq(port->irq, apbuart_int, 0, "apbuart", port);
<------>if (retval)
<------><------>return retval;
 
<------>/* Finally, enable interrupts */
<------>cr = UART_GET_CTRL(port);
<------>UART_PUT_CTRL(port,
<------><------>      cr | UART_CTRL_RE | UART_CTRL_TE |
<------><------>      UART_CTRL_RI | UART_CTRL_TI);
 
<------>return 0;
}
 
static void apbuart_shutdown(struct uart_port *port)
{
<------>unsigned int cr;
 
<------>/* disable all interrupts, disable the port */
<------>cr = UART_GET_CTRL(port);
<------>UART_PUT_CTRL(port,
<------><------>      cr & ~(UART_CTRL_RE | UART_CTRL_TE |
<------><------><------>     UART_CTRL_RI | UART_CTRL_TI));
 
<------>/* Free the interrupt */
<------>free_irq(port->irq, port);
}
 
static void apbuart_set_termios(struct uart_port *port,
<------><------><------><------>struct ktermios *termios, struct ktermios *old)
{
<------>unsigned int cr;
<------>unsigned long flags;
<------>unsigned int baud, quot;
 
<------>/* Ask the core to calculate the divisor for us. */
<------>baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
<------>if (baud == 0)
<------><------>panic("invalid baudrate %i\n", port->uartclk / 16);
 
<------>/* uart_get_divisor calc a *16 uart freq, apbuart is *8 */
<------>quot = (uart_get_divisor(port, baud)) * 2;
<------>cr = UART_GET_CTRL(port);
<------>cr &= ~(UART_CTRL_PE | UART_CTRL_PS);
 
<------>if (termios->c_cflag & PARENB) {
<------><------>cr |= UART_CTRL_PE;
<------><------>if ((termios->c_cflag & PARODD))
<------><------><------>cr |= UART_CTRL_PS;
<------>}
 
<------>/* Enable flow control. */
<------>if (termios->c_cflag & CRTSCTS)
<------><------>cr |= UART_CTRL_FL;
 
<------>spin_lock_irqsave(&port->lock, flags);
 
<------>/* Update the per-port timeout. */
<------>uart_update_timeout(port, termios->c_cflag, baud);
 
<------>port->read_status_mask = UART_STATUS_OE;
<------>if (termios->c_iflag & INPCK)
<------><------>port->read_status_mask |= UART_STATUS_FE | UART_STATUS_PE;
 
<------>/* Characters to ignore */
<------>port->ignore_status_mask = 0;
<------>if (termios->c_iflag & IGNPAR)
<------><------>port->ignore_status_mask |= UART_STATUS_FE | UART_STATUS_PE;
 
<------>/* Ignore all characters if CREAD is not set. */
<------>if ((termios->c_cflag & CREAD) == 0)
<------><------>port->ignore_status_mask |= UART_DUMMY_RSR_RX;
 
<------>/* Set baud rate */
<------>quot -= 1;
<------>UART_PUT_SCAL(port, quot);
<------>UART_PUT_CTRL(port, cr);
 
<------>spin_unlock_irqrestore(&port->lock, flags);
}
 
static const char *apbuart_type(struct uart_port *port)
{
<------>return port->type == PORT_APBUART ? "GRLIB/APBUART" : NULL;
}
 
static void apbuart_release_port(struct uart_port *port)
{
<------>release_mem_region(port->mapbase, 0x100);
}
 
static int apbuart_request_port(struct uart_port *port)
{
<------>return request_mem_region(port->mapbase, 0x100, "grlib-apbuart")
<------>    != NULL ? 0 : -EBUSY;
<------>return 0;
}
 
/* Configure/autoconfigure the port */
static void apbuart_config_port(struct uart_port *port, int flags)
{
<------>if (flags & UART_CONFIG_TYPE) {
<------><------>port->type = PORT_APBUART;
<------><------>apbuart_request_port(port);
<------>}
}
 
/* Verify the new serial_struct (for TIOCSSERIAL) */
static int apbuart_verify_port(struct uart_port *port,
<------><------><------>       struct serial_struct *ser)
{
<------>int ret = 0;
<------>if (ser->type != PORT_UNKNOWN && ser->type != PORT_APBUART)
<------><------>ret = -EINVAL;
<------>if (ser->irq < 0 || ser->irq >= NR_IRQS)
<------><------>ret = -EINVAL;
<------>if (ser->baud_base < 9600)
<------><------>ret = -EINVAL;
<------>return ret;
}
 
static const struct uart_ops grlib_apbuart_ops = {
<------>.tx_empty = apbuart_tx_empty,
<------>.set_mctrl = apbuart_set_mctrl,
<------>.get_mctrl = apbuart_get_mctrl,
<------>.stop_tx = apbuart_stop_tx,
<------>.start_tx = apbuart_start_tx,
<------>.stop_rx = apbuart_stop_rx,
<------>.break_ctl = apbuart_break_ctl,
<------>.startup = apbuart_startup,
<------>.shutdown = apbuart_shutdown,
<------>.set_termios = apbuart_set_termios,
<------>.type = apbuart_type,
<------>.release_port = apbuart_release_port,
<------>.request_port = apbuart_request_port,
<------>.config_port = apbuart_config_port,
<------>.verify_port = apbuart_verify_port,
};
 
static struct uart_port grlib_apbuart_ports[UART_NR];
static struct device_node *grlib_apbuart_nodes[UART_NR];
 
static int apbuart_scan_fifo_size(struct uart_port *port, int portnumber)
{
<------>int ctrl, loop = 0;
<------>int status;
<------>int fifosize;
<------>unsigned long flags;
 
<------>ctrl = UART_GET_CTRL(port);
 
<------>/*
<------> * Enable the transceiver and wait for it to be ready to send data.
<------> * Clear interrupts so that this process will not be externally
<------> * interrupted in the middle (which can cause the transceiver to
<------> * drain prematurely).
<------> */
 
<------>local_irq_save(flags);
 
<------>UART_PUT_CTRL(port, ctrl | UART_CTRL_TE);
 
<------>while (!UART_TX_READY(UART_GET_STATUS(port)))
<------><------>loop++;
 
<------>/*
<------> * Disable the transceiver so data isn't actually sent during the
<------> * actual test.
<------> */
 
<------>UART_PUT_CTRL(port, ctrl & ~(UART_CTRL_TE));
 
<------>fifosize = 1;
<------>UART_PUT_CHAR(port, 0);
 
<------>/*
<------> * So long as transmitting a character increments the tranceivier FIFO
<------> * length the FIFO must be at least that big. These bytes will
<------> * automatically drain off of the FIFO.
<------> */
 
<------>status = UART_GET_STATUS(port);
<------>while (((status >> 20) & 0x3F) == fifosize) {
<------><------>fifosize++;
<------><------>UART_PUT_CHAR(port, 0);
<------><------>status = UART_GET_STATUS(port);
<------>}
 
<------>fifosize--;
 
<------>UART_PUT_CTRL(port, ctrl);
<------>local_irq_restore(flags);
 
<------>if (fifosize == 0)
<------><------>fifosize = 1;
 
<------>return fifosize;
}
 
static void apbuart_flush_fifo(struct uart_port *port)
{
<------>int i;
 
<------>for (i = 0; i < port->fifosize; i++)
<------><------>UART_GET_CHAR(port);
}
 
 
/* ======================================================================== */
/* Console driver, if enabled                                               */
/* ======================================================================== */
 
#ifdef CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE
 
static void apbuart_console_putchar(struct uart_port *port, int ch)
{
<------>unsigned int status;
<------>do {
<------><------>status = UART_GET_STATUS(port);
<------>} while (!UART_TX_READY(status));
<------>UART_PUT_CHAR(port, ch);
}
 
static void
apbuart_console_write(struct console *co, const char *s, unsigned int count)
{
<------>struct uart_port *port = &grlib_apbuart_ports[co->index];
<------>unsigned int status, old_cr, new_cr;
 
<------>/* First save the CR then disable the interrupts */
<------>old_cr = UART_GET_CTRL(port);
<------>new_cr = old_cr & ~(UART_CTRL_RI | UART_CTRL_TI);
<------>UART_PUT_CTRL(port, new_cr);
 
<------>uart_console_write(port, s, count, apbuart_console_putchar);
 
<------>/*
<------> *      Finally, wait for transmitter to become empty
<------> *      and restore the TCR
<------> */
<------>do {
<------><------>status = UART_GET_STATUS(port);
<------>} while (!UART_TX_READY(status));
<------>UART_PUT_CTRL(port, old_cr);
}
 
static void __init
apbuart_console_get_options(struct uart_port *port, int *baud,
<------><------><------>    int *parity, int *bits)
{
<------>if (UART_GET_CTRL(port) & (UART_CTRL_RE | UART_CTRL_TE)) {
 
<------><------>unsigned int quot, status;
<------><------>status = UART_GET_STATUS(port);
 
<------><------>*parity = 'n';
<------><------>if (status & UART_CTRL_PE) {
<------><------><------>if ((status & UART_CTRL_PS) == 0)
<------><------><------><------>*parity = 'e';
<------><------><------>else
<------><------><------><------>*parity = 'o';
<------><------>}
 
<------><------>*bits = 8;
<------><------>quot = UART_GET_SCAL(port) / 8;
<------><------>*baud = port->uartclk / (16 * (quot + 1));
<------>}
}
 
static int __init apbuart_console_setup(struct console *co, char *options)
{
<------>struct uart_port *port;
<------>int baud = 38400;
<------>int bits = 8;
<------>int parity = 'n';
<------>int flow = 'n';
 
<------>pr_debug("apbuart_console_setup co=%p, co->index=%i, options=%s\n",
<------><------> co, co->index, options);
 
<------>/*
<------> * Check whether an invalid uart number has been specified, and
<------> * if so, search for the first available port that does have
<------> * console support.
<------> */
<------>if (co->index >= grlib_apbuart_port_nr)
<------><------>co->index = 0;
 
<------>port = &grlib_apbuart_ports[co->index];
 
<------>spin_lock_init(&port->lock);
 
<------>if (options)
<------><------>uart_parse_options(options, &baud, &parity, &bits, &flow);
<------>else
<------><------>apbuart_console_get_options(port, &baud, &parity, &bits);
 
<------>return uart_set_options(port, co, baud, parity, bits, flow);
}
 
static struct uart_driver grlib_apbuart_driver;
 
static struct console grlib_apbuart_console = {
<------>.name = "ttyS",
<------>.write = apbuart_console_write,
<------>.device = uart_console_device,
<------>.setup = apbuart_console_setup,
<------>.flags = CON_PRINTBUFFER,
<------>.index = -1,
<------>.data = &grlib_apbuart_driver,
};
 
 
static int grlib_apbuart_configure(void);
 
static int __init apbuart_console_init(void)
{
<------>if (grlib_apbuart_configure())
<------><------>return -ENODEV;
<------>register_console(&grlib_apbuart_console);
<------>return 0;
}
 
console_initcall(apbuart_console_init);
 
#define APBUART_CONSOLE	(&grlib_apbuart_console)
#else
#define APBUART_CONSOLE	NULL
#endif
 
static struct uart_driver grlib_apbuart_driver = {
<------>.owner = THIS_MODULE,
<------>.driver_name = "serial",
<------>.dev_name = "ttyS",
<------>.major = SERIAL_APBUART_MAJOR,
<------>.minor = SERIAL_APBUART_MINOR,
<------>.nr = UART_NR,
<------>.cons = APBUART_CONSOLE,
};
 
 
/* ======================================================================== */
/* OF Platform Driver                                                       */
/* ======================================================================== */
 
static int apbuart_probe(struct platform_device *op)
{
<------>int i;
<------>struct uart_port *port = NULL;
 
<------>for (i = 0; i < grlib_apbuart_port_nr; i++) {
<------><------>if (op->dev.of_node == grlib_apbuart_nodes[i])
<------><------><------>break;
<------>}
 
<------>port = &grlib_apbuart_ports[i];
<------>port->dev = &op->dev;
<------>port->irq = op->archdata.irqs[0];
 
<------>uart_add_one_port(&grlib_apbuart_driver, (struct uart_port *) port);
 
<------>apbuart_flush_fifo((struct uart_port *) port);
 
<------>printk(KERN_INFO "grlib-apbuart at 0x%llx, irq %d\n",
<------>       (unsigned long long) port->mapbase, port->irq);
<------>return 0;
}
 
static const struct of_device_id apbuart_match[] = {
<------>{
<------> .name = "GAISLER_APBUART",
<------> },
<------>{
<------> .name = "01_00c",
<------> },
<------>{},
};
MODULE_DEVICE_TABLE(of, apbuart_match);
 
static struct platform_driver grlib_apbuart_of_driver = {
<------>.probe = apbuart_probe,
<------>.driver = {
<------><------>.name = "grlib-apbuart",
<------><------>.of_match_table = apbuart_match,
<------>},
};
 
 
static int __init grlib_apbuart_configure(void)
{
<------>struct device_node *np;
<------>int line = 0;
 
<------>for_each_matching_node(np, apbuart_match) {
<------><------>const int *ampopts;
<------><------>const u32 *freq_hz;
<------><------>const struct amba_prom_registers *regs;
<------><------>struct uart_port *port;
<------><------>unsigned long addr;
 
<------><------>ampopts = of_get_property(np, "ampopts", NULL);
<------><------>if (ampopts && (*ampopts == 0))
<------><------><------>continue; /* Ignore if used by another OS instance */
<------><------>regs = of_get_property(np, "reg", NULL);
<------><------>/* Frequency of APB Bus is frequency of UART */
<------><------>freq_hz = of_get_property(np, "freq", NULL);
 
<------><------>if (!regs || !freq_hz || (*freq_hz == 0))
<------><------><------>continue;
 
<------><------>grlib_apbuart_nodes[line] = np;
 
<------><------>addr = regs->phys_addr;
 
<------><------>port = &grlib_apbuart_ports[line];
 
<------><------>port->mapbase = addr;
<------><------>port->membase = ioremap(addr, sizeof(struct grlib_apbuart_regs_map));
<------><------>port->irq = 0;
<------><------>port->iotype = UPIO_MEM;
<------><------>port->ops = &grlib_apbuart_ops;
<------><------>port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE);
<------><------>port->flags = UPF_BOOT_AUTOCONF;
<------><------>port->line = line;
<------><------>port->uartclk = *freq_hz;
<------><------>port->fifosize = apbuart_scan_fifo_size((struct uart_port *) port, line);
<------><------>line++;
 
<------><------>/* We support maximum UART_NR uarts ... */
<------><------>if (line == UART_NR)
<------><------><------>break;
<------>}
 
<------>grlib_apbuart_driver.nr = grlib_apbuart_port_nr = line;
<------>return line ? 0 : -ENODEV;
}
 
static int __init grlib_apbuart_init(void)
{
<------>int ret;
 
<------>/* Find all APBUARTS in device the tree and initialize their ports */
<------>ret = grlib_apbuart_configure();
<------>if (ret)
<------><------>return ret;
 
<------>printk(KERN_INFO "Serial: GRLIB APBUART driver\n");
 
<------>ret = uart_register_driver(&grlib_apbuart_driver);
 
<------>if (ret) {
<------><------>printk(KERN_ERR "%s: uart_register_driver failed (%i)\n",
<------><------>       __FILE__, ret);
<------><------>return ret;
<------>}
 
<------>ret = platform_driver_register(&grlib_apbuart_of_driver);
<------>if (ret) {
<------><------>printk(KERN_ERR
<------><------>       "%s: platform_driver_register failed (%i)\n",
<------><------>       __FILE__, ret);
<------><------>uart_unregister_driver(&grlib_apbuart_driver);
<------><------>return ret;
<------>}
 
<------>return ret;
}
 
static void __exit grlib_apbuart_exit(void)
{
<------>int i;
 
<------>for (i = 0; i < grlib_apbuart_port_nr; i++)
<------><------>uart_remove_one_port(&grlib_apbuart_driver,
<------><------><------><------>     &grlib_apbuart_ports[i]);
 
<------>uart_unregister_driver(&grlib_apbuart_driver);
<------>platform_driver_unregister(&grlib_apbuart_of_driver);
}
 
module_init(grlib_apbuart_init);
module_exit(grlib_apbuart_exit);
 
MODULE_AUTHOR("Aeroflex Gaisler AB");
MODULE_DESCRIPTION("GRLIB APBUART serial driver");
MODULE_VERSION("2.1");
MODULE_LICENSE("GPL");