// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2010 Alexey Charkov <[email protected]>
*
* Based on msm_serial.c, which is:
* Copyright (C) 2007 Google, Inc.
* Author: Robert Love <[email protected]>
*/
#include <linux/hrtimer.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/err.h>
/*
* UART Register offsets
*/
#define VT8500_URTDR 0x0000 /* Transmit data */
#define VT8500_URRDR 0x0004 /* Receive data */
#define VT8500_URDIV 0x0008 /* Clock/Baud rate divisor */
#define VT8500_URLCR 0x000C /* Line control */
#define VT8500_URICR 0x0010 /* IrDA control */
#define VT8500_URIER 0x0014 /* Interrupt enable */
#define VT8500_URISR 0x0018 /* Interrupt status */
#define VT8500_URUSR 0x001c /* UART status */
#define VT8500_URFCR 0x0020 /* FIFO control */
#define VT8500_URFIDX 0x0024 /* FIFO index */
#define VT8500_URBKR 0x0028 /* Break signal count */
#define VT8500_URTOD 0x002c /* Time out divisor */
#define VT8500_TXFIFO 0x1000 /* Transmit FIFO (16x8) */
#define VT8500_RXFIFO 0x1020 /* Receive FIFO (16x10) */
/*
* Interrupt enable and status bits
*/
#define TXDE (1 << 0) /* Tx Data empty */
#define RXDF (1 << 1) /* Rx Data full */
#define TXFAE (1 << 2) /* Tx FIFO almost empty */
#define TXFE (1 << 3) /* Tx FIFO empty */
#define RXFAF (1 << 4) /* Rx FIFO almost full */
#define RXFF (1 << 5) /* Rx FIFO full */
#define TXUDR (1 << 6) /* Tx underrun */
#define RXOVER (1 << 7) /* Rx overrun */
#define PER (1 << 8) /* Parity error */
#define FER (1 << 9) /* Frame error */
#define TCTS (1 << 10) /* Toggle of CTS */
#define RXTOUT (1 << 11) /* Rx timeout */
#define BKDONE (1 << 12) /* Break signal done */
#define ERR (1 << 13) /* AHB error response */
#define RX_FIFO_INTS (RXFAF | RXFF | RXOVER | PER | FER | RXTOUT)
#define TX_FIFO_INTS (TXFAE | TXFE | TXUDR)
/*
* Line control bits
*/
#define VT8500_TXEN (1 << 0) /* Enable transmit logic */
#define VT8500_RXEN (1 << 1) /* Enable receive logic */
#define VT8500_CS8 (1 << 2) /* 8-bit data length (vs. 7-bit) */
#define VT8500_CSTOPB (1 << 3) /* 2 stop bits (vs. 1) */
#define VT8500_PARENB (1 << 4) /* Enable parity */
#define VT8500_PARODD (1 << 5) /* Odd parity (vs. even) */
#define VT8500_RTS (1 << 6) /* Ready to send */
#define VT8500_LOOPBK (1 << 7) /* Enable internal loopback */
#define VT8500_DMA (1 << 8) /* Enable DMA mode (needs FIFO) */
#define VT8500_BREAK (1 << 9) /* Initiate break signal */
#define VT8500_PSLVERR (1 << 10) /* APB error upon empty RX FIFO read */
#define VT8500_SWRTSCTS (1 << 11) /* Software-controlled RTS/CTS */
/*
* Capability flags (driver-internal)
*/
#define VT8500_HAS_SWRTSCTS_SWITCH (1 << 1)
#define VT8500_RECOMMENDED_CLK 12000000
#define VT8500_OVERSAMPLING_DIVISOR 13
#define VT8500_MAX_PORTS 6
struct vt8500_port {
struct uart_port uart;
char name[16];
struct clk *clk;
unsigned int clk_predivisor;
unsigned int ier;
unsigned int vt8500_uart_flags;
};
/*
* we use this variable to keep track of which ports
* have been allocated as we can't use pdev->id in
* devicetree
*/
static DECLARE_BITMAP(vt8500_ports_in_use, VT8500_MAX_PORTS);
static inline void vt8500_write(struct uart_port *port, unsigned int val,
unsigned int off)
{
writel(val, port->membase + off);
}
static inline unsigned int vt8500_read(struct uart_port *port, unsigned int off)
{
return readl(port->membase + off);
}
static void vt8500_stop_tx(struct uart_port *port)
{
struct vt8500_port *vt8500_port = container_of(port,
struct vt8500_port,
uart);
vt8500_port->ier &= ~TX_FIFO_INTS;
vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}
static void vt8500_stop_rx(struct uart_port *port)
{
struct vt8500_port *vt8500_port = container_of(port,
struct vt8500_port,
uart);
vt8500_port->ier &= ~RX_FIFO_INTS;
vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}
static void vt8500_enable_ms(struct uart_port *port)
{
struct vt8500_port *vt8500_port = container_of(port,
struct vt8500_port,
uart);
vt8500_port->ier |= TCTS;
vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}
static void handle_rx(struct uart_port *port)
{
struct tty_port *tport = &port->state->port;
/*
* Handle overrun
*/
if ((vt8500_read(port, VT8500_URISR) & RXOVER)) {
port->icount.overrun++;
tty_insert_flip_char(tport, 0, TTY_OVERRUN);
}
/* and now the main RX loop */
while (vt8500_read(port, VT8500_URFIDX) & 0x1f00) {
unsigned int c;
char flag = TTY_NORMAL;
c = readw(port->membase + VT8500_RXFIFO) & 0x3ff;
/* Mask conditions we're ignoring. */
c &= ~port->read_status_mask;
if (c & FER) {
port->icount.frame++;
flag = TTY_FRAME;
} else if (c & PER) {
port->icount.parity++;
flag = TTY_PARITY;
}
port->icount.rx++;
if (!uart_handle_sysrq_char(port, c))
tty_insert_flip_char(tport, c, flag);
}
tty_flip_buffer_push(tport);
}
static unsigned int vt8500_tx_empty(struct uart_port *port)
{
unsigned int idx = vt8500_read(port, VT8500_URFIDX) & 0x1f;
return idx < 16 ? TIOCSER_TEMT : 0;
}
static void handle_tx(struct uart_port *port)
{
u8 ch;
uart_port_tx(port, ch,
vt8500_tx_empty(port),
writeb(ch, port->membase + VT8500_TXFIFO));
}
static void vt8500_start_tx(struct uart_port *port)
{
struct vt8500_port *vt8500_port = container_of(port,
struct vt8500_port,
uart);
vt8500_port->ier &= ~TX_FIFO_INTS;
vt8500_write(port, vt8500_port->ier, VT8500_URIER);
handle_tx(port);
vt8500_port->ier |= TX_FIFO_INTS;
vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}
static void handle_delta_cts(struct uart_port *port)
{
port->icount.cts++;
wake_up_interruptible(&port->state->port.delta_msr_wait);
}
static irqreturn_t vt8500_irq(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
unsigned long isr;
uart_port_lock(port);
isr = vt8500_read(port, VT8500_URISR);
/* Acknowledge active status bits */
vt8500_write(port, isr, VT8500_URISR);
if (isr & RX_FIFO_INTS)
handle_rx(port);
if (isr & TX_FIFO_INTS)
handle_tx(port);
if (isr & TCTS)
handle_delta_cts(port);
uart_port_unlock(port);
return IRQ_HANDLED;
}
static unsigned int vt8500_get_mctrl(struct uart_port *port)
{
unsigned int usr;
usr = vt8500_read(port, VT8500_URUSR);
if (usr & (1 << 4))
return TIOCM_CTS;
else
return 0;
}
static void vt8500_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
unsigned int lcr = vt8500_read(port, VT8500_URLCR);
if (mctrl & TIOCM_RTS)
lcr |= VT8500_RTS;
else
lcr &= ~VT8500_RTS;
vt8500_write(port, lcr, VT8500_URLCR);
}
static void vt8500_break_ctl(struct uart_port *port, int break_ctl)
{
if (break_ctl)
vt8500_write(port,
vt8500_read(port, VT8500_URLCR) | VT8500_BREAK,
VT8500_URLCR);
}
static int vt8500_set_baud_rate(struct uart_port *port, unsigned int baud)
{
struct vt8500_port *vt8500_port =
container_of(port, struct vt8500_port, uart);
unsigned long div;
unsigned int loops = 1000;
div = ((vt8500_port->clk_predivisor - 1) & 0xf) << 16;
div |= (uart_get_divisor(port, baud) - 1) & 0x3ff;
/* Effective baud rate */
baud = port->uartclk / 16 / ((div & 0x3ff) + 1);
while ((vt8500_read(port, VT8500_URUSR) & (1 << 5)) && --loops)
cpu_relax();
vt8500_write(port, div, VT8500_URDIV);
/* Break signal timing depends on baud rate, update accordingly */
vt8500_write(port, mult_frac(baud, 4096, 1000000), VT8500_URBKR);
return baud;
}
static int vt8500_startup(struct uart_port *port)
{
struct vt8500_port *vt8500_port =
container_of(port, struct vt8500_port, uart);
int ret;
snprintf(vt8500_port->name, sizeof(vt8500_port->name),
"vt8500_serial%d", port->line);
ret = request_irq(port->irq, vt8500_irq, IRQF_TRIGGER_HIGH,
vt8500_port->name, port);
if (unlikely(ret))
return ret;
vt8500_write(port, 0x03, VT8500_URLCR); /* enable TX & RX */
return 0;
}
static void vt8500_shutdown(struct uart_port *port)
{
struct vt8500_port *vt8500_port =
container_of(port, struct vt8500_port, uart);
vt8500_port->ier = 0;
/* disable interrupts and FIFOs */
vt8500_write(&vt8500_port->uart, 0, VT8500_URIER);
vt8500_write(&vt8500_port->uart, 0x880, VT8500_URFCR);
free_irq(port->irq, port);
}
static void vt8500_set_termios(struct uart_port *port,
struct ktermios *termios,
const struct ktermios *old)
{
struct vt8500_port *vt8500_port =
container_of(port, struct vt8500_port, uart);
unsigned long flags;
unsigned int baud, lcr;
unsigned int loops = 1000;
uart_port_lock_irqsave(port, &flags);
/* calculate and set baud rate */
baud = uart_get_baud_rate(port, termios, old, 900, 921600);
baud = vt8500_set_baud_rate(port, baud);
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);
/* calculate parity */
lcr = vt8500_read(&vt8500_port->uart, VT8500_URLCR);
lcr &= ~(VT8500_PARENB | VT8500_PARODD);
if (termios->c_cflag & PARENB) {
lcr |= VT8500_PARENB;
termios->c_cflag &= ~CMSPAR;
if (termios->c_cflag & PARODD)
lcr |= VT8500_PARODD;
}
/* calculate bits per char */
lcr &= ~VT8500_CS8;
switch (termios->c_cflag & CSIZE) {
case CS7:
break;
case CS8:
default:
lcr |= VT8500_CS8;
termios->c_cflag &= ~CSIZE;
termios->c_cflag |= CS8;
break;
}
/* calculate stop bits */
lcr &= ~VT8500_CSTOPB;
if (termios->c_cflag & CSTOPB)
lcr |= VT8500_CSTOPB;
lcr &= ~VT8500_SWRTSCTS;
if (vt8500_port->vt8500_uart_flags & VT8500_HAS_SWRTSCTS_SWITCH)
lcr |= VT8500_SWRTSCTS;
/* set parity, bits per char, and stop bit */
vt8500_write(&vt8500_port->uart, lcr, VT8500_URLCR);
/* Configure status bits to ignore based on termio flags. */
port->read_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->read_status_mask = FER | PER;
uart_update_timeout(port, termios->c_cflag, baud);
/* Reset FIFOs */
vt8500_write(&vt8500_port->uart, 0x88c, VT8500_URFCR);
while ((vt8500_read(&vt8500_port->uart, VT8500_URFCR) & 0xc)
&& --loops)
cpu_relax();
/* Every possible FIFO-related interrupt */
vt8500_port->ier = RX_FIFO_INTS | TX_FIFO_INTS;
/*
* CTS flow control
*/
if (UART_ENABLE_MS(&vt8500_port->uart, termios->c_cflag))
vt8500_port->ier |= TCTS;
vt8500_write(&vt8500_port->uart, 0x881, VT8500_URFCR);
vt8500_write(&vt8500_port->uart, vt8500_port->ier, VT8500_URIER);
uart_port_unlock_irqrestore(port, flags);
}
static const char *vt8500_type(struct uart_port *port)
{
struct vt8500_port *vt8500_port =
container_of(port, struct vt8500_port, uart);
return vt8500_port->name;
}
static void vt8500_release_port(struct uart_port *port)
{
}
static int vt8500_request_port(struct uart_port *port)
{
return 0;
}
static void vt8500_config_port(struct uart_port *port, int flags)
{
port->type = PORT_VT8500;
}
static int vt8500_verify_port(struct uart_port *port,
struct serial_struct *ser)
{
if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_VT8500))
return -EINVAL;
if (unlikely(port->irq != ser->irq))
return -EINVAL;
return 0;
}
static struct vt8500_port *vt8500_uart_ports[VT8500_MAX_PORTS];
static struct uart_driver vt8500_uart_driver;
#ifdef CONFIG_SERIAL_VT8500_CONSOLE
static void wait_for_xmitr(struct uart_port *port)
{
unsigned int status, tmout = 10000;
/* Wait up to 10ms for the character(s) to be sent. */
do {
status = vt8500_read(port, VT8500_URFIDX);
if (--tmout == 0)
break;
udelay(1);
} while (status & 0x10);
}
static void vt8500_console_putchar(struct uart_port *port, unsigned char c)
{
wait_for_xmitr(port);
writeb(c, port->membase + VT8500_TXFIFO);
}
static void vt8500_console_write(struct console *co, const char *s,
unsigned int count)
{
struct vt8500_port *vt8500_port = vt8500_uart_ports[co->index];
unsigned long ier;
BUG_ON(co->index < 0 || co->index >= vt8500_uart_driver.nr);
ier = vt8500_read(&vt8500_port->uart, VT8500_URIER);
vt8500_write(&vt8500_port->uart, VT8500_URIER, 0);
uart_console_write(&vt8500_port->uart, s, count,
vt8500_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and switch back to FIFO
*/
wait_for_xmitr(&vt8500_port->uart);
vt8500_write(&vt8500_port->uart, VT8500_URIER, ier);
}
static int __init vt8500_console_setup(struct console *co, char *options)
{
struct vt8500_port *vt8500_port;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (unlikely(co->index >= vt8500_uart_driver.nr || co->index < 0))
return -ENXIO;
vt8500_port = vt8500_uart_ports[co->index];
if (!vt8500_port)
return -ENODEV;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(&vt8500_port->uart,
co, baud, parity, bits, flow);
}
static struct console vt8500_console = {
.name = "ttyWMT",
.write = vt8500_console_write,
.device = uart_console_device,
.setup = vt8500_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &vt8500_uart_driver,
};
#define VT8500_CONSOLE (&vt8500_console)
#else
#define VT8500_CONSOLE NULL
#endif
#ifdef CONFIG_CONSOLE_POLL
static int vt8500_get_poll_char(struct uart_port *port)
{
unsigned int status = vt8500_read(port, VT8500_URFIDX);
if (!(status & 0x1f00))
return NO_POLL_CHAR;
return vt8500_read(port, VT8500_RXFIFO) & 0xff;
}
static void vt8500_put_poll_char(struct uart_port *port, unsigned char c)
{
unsigned int status, tmout = 10000;
do {
status = vt8500_read(port, VT8500_URFIDX);
if (--tmout == 0)
break;
udelay(1);
} while (status & 0x10);
vt8500_write(port, c, VT8500_TXFIFO);
}
#endif
static const struct uart_ops vt8500_uart_pops = {
.tx_empty = vt8500_tx_empty,
.set_mctrl = vt8500_set_mctrl,
.get_mctrl = vt8500_get_mctrl,
.stop_tx = vt8500_stop_tx,
.start_tx = vt8500_start_tx,
.stop_rx = vt8500_stop_rx,
.enable_ms = vt8500_enable_ms,
.break_ctl = vt8500_break_ctl,
.startup = vt8500_startup,
.shutdown = vt8500_shutdown,
.set_termios = vt8500_set_termios,
.type = vt8500_type,
.release_port = vt8500_release_port,
.request_port = vt8500_request_port,
.config_port = vt8500_config_port,
.verify_port = vt8500_verify_port,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = vt8500_get_poll_char,
.poll_put_char = vt8500_put_poll_char,
#endif
};
static struct uart_driver vt8500_uart_driver = {
.owner = THIS_MODULE,
.driver_name = "vt8500_serial",
.dev_name = "ttyWMT",
.nr = 6,
.cons = VT8500_CONSOLE,
};
static unsigned int vt8500_flags; /* none required so far */
static unsigned int wm8880_flags = VT8500_HAS_SWRTSCTS_SWITCH;
static const struct of_device_id wmt_dt_ids[] = {
{ .compatible = "via,vt8500-uart", .data = &vt8500_flags},
{ .compatible = "wm,wm8880-uart", .data = &wm8880_flags},
{}
};
static int vt8500_serial_probe(struct platform_device *pdev)
{
struct vt8500_port *vt8500_port;
struct resource *mmres;
struct device_node *np = pdev->dev.of_node;
const unsigned int *flags;
int ret;
int port;
int irq;
flags = of_device_get_match_data(&pdev->dev);
if (!flags)
return -EINVAL;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
if (np) {
port = of_alias_get_id(np, "serial");
if (port >= VT8500_MAX_PORTS)
port = -1;
} else {
port = -1;
}
if (port < 0) {
/* calculate the port id */
port = find_first_zero_bit(vt8500_ports_in_use,
VT8500_MAX_PORTS);
}
if (port >= VT8500_MAX_PORTS)
return -ENODEV;
/* reserve the port id */
if (test_and_set_bit(port, vt8500_ports_in_use)) {
/* port already in use - shouldn't really happen */
return -EBUSY;
}
vt8500_port = devm_kzalloc(&pdev->dev, sizeof(struct vt8500_port),
GFP_KERNEL);
if (!vt8500_port)
return -ENOMEM;
vt8500_port->uart.membase = devm_platform_get_and_ioremap_resource(pdev, 0, &mmres);
if (IS_ERR(vt8500_port->uart.membase))
return PTR_ERR(vt8500_port->uart.membase);
vt8500_port->clk = of_clk_get(pdev->dev.of_node, 0);
if (IS_ERR(vt8500_port->clk)) {
dev_err(&pdev->dev, "failed to get clock\n");
return -EINVAL;
}
ret = clk_prepare_enable(vt8500_port->clk);
if (ret) {
dev_err(&pdev->dev, "failed to enable clock\n");
return ret;
}
vt8500_port->vt8500_uart_flags = *flags;
vt8500_port->clk_predivisor = DIV_ROUND_CLOSEST(
clk_get_rate(vt8500_port->clk),
VT8500_RECOMMENDED_CLK
);
vt8500_port->uart.type = PORT_VT8500;
vt8500_port->uart.iotype = UPIO_MEM;
vt8500_port->uart.mapbase = mmres->start;
vt8500_port->uart.irq = irq;
vt8500_port->uart.fifosize = 16;
vt8500_port->uart.ops = &vt8500_uart_pops;
vt8500_port->uart.line = port;
vt8500_port->uart.dev = &pdev->dev;
vt8500_port->uart.flags = UPF_IOREMAP | UPF_BOOT_AUTOCONF;
vt8500_port->uart.has_sysrq = IS_ENABLED(CONFIG_SERIAL_VT8500_CONSOLE);
/* Serial core uses the magic "16" everywhere - adjust for it */
vt8500_port->uart.uartclk = 16 * clk_get_rate(vt8500_port->clk) /
vt8500_port->clk_predivisor /
VT8500_OVERSAMPLING_DIVISOR;
snprintf(vt8500_port->name, sizeof(vt8500_port->name),
"VT8500 UART%d", pdev->id);
vt8500_uart_ports[port] = vt8500_port;
uart_add_one_port(&vt8500_uart_driver, &vt8500_port->uart);
platform_set_drvdata(pdev, vt8500_port);
return 0;
}
static struct platform_driver vt8500_platform_driver = {
.probe = vt8500_serial_probe,
.driver = {
.name = "vt8500_serial",
.of_match_table = wmt_dt_ids,
.suppress_bind_attrs = true,
},
};
static int __init vt8500_serial_init(void)
{
int ret;
ret = uart_register_driver(&vt8500_uart_driver);
if (unlikely(ret))
return ret;
ret = platform_driver_register(&vt8500_platform_driver);
if (unlikely(ret))
uart_unregister_driver(&vt8500_uart_driver);
return ret;
}
device_initcall(vt8500_serial_init);
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