diff options
Diffstat (limited to 'drivers/tty/serial/amba-pl010.c')
-rw-r--r-- | drivers/tty/serial/amba-pl010.c | 804 |
1 files changed, 804 insertions, 0 deletions
diff --git a/drivers/tty/serial/amba-pl010.c b/drivers/tty/serial/amba-pl010.c new file mode 100644 index 0000000000..b5a7404cba --- /dev/null +++ b/drivers/tty/serial/amba-pl010.c @@ -0,0 +1,804 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Driver for AMBA serial ports + * + * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. + * + * Copyright 1999 ARM Limited + * Copyright (C) 2000 Deep Blue Solutions Ltd. + * + * This is a generic driver for ARM AMBA-type serial ports. They + * have a lot of 16550-like features, but are not register compatible. + * Note that although they do have CTS, DCD and DSR inputs, they do + * not have an RI input, nor do they have DTR or RTS outputs. If + * required, these have to be supplied via some other means (eg, GPIO) + * and hooked into this driver. + */ + +#include <linux/module.h> +#include <linux/ioport.h> +#include <linux/init.h> +#include <linux/console.h> +#include <linux/sysrq.h> +#include <linux/device.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/serial_core.h> +#include <linux/serial.h> +#include <linux/amba/bus.h> +#include <linux/amba/serial.h> +#include <linux/clk.h> +#include <linux/slab.h> +#include <linux/io.h> + +#define UART_NR 8 + +#define SERIAL_AMBA_MAJOR 204 +#define SERIAL_AMBA_MINOR 16 +#define SERIAL_AMBA_NR UART_NR + +#define AMBA_ISR_PASS_LIMIT 256 + +#define UART_RX_DATA(s) (((s) & UART01x_FR_RXFE) == 0) +#define UART_TX_READY(s) (((s) & UART01x_FR_TXFF) == 0) + +#define UART_DUMMY_RSR_RX 256 +#define UART_PORT_SIZE 64 + +/* + * We wrap our port structure around the generic uart_port. + */ +struct uart_amba_port { + struct uart_port port; + struct clk *clk; + struct amba_device *dev; + struct amba_pl010_data *data; + unsigned int old_status; +}; + +static void pl010_stop_tx(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned int cr; + + cr = readb(uap->port.membase + UART010_CR); + cr &= ~UART010_CR_TIE; + writel(cr, uap->port.membase + UART010_CR); +} + +static void pl010_start_tx(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned int cr; + + cr = readb(uap->port.membase + UART010_CR); + cr |= UART010_CR_TIE; + writel(cr, uap->port.membase + UART010_CR); +} + +static void pl010_stop_rx(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned int cr; + + cr = readb(uap->port.membase + UART010_CR); + cr &= ~(UART010_CR_RIE | UART010_CR_RTIE); + writel(cr, uap->port.membase + UART010_CR); +} + +static void pl010_disable_ms(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + unsigned int cr; + + cr = readb(uap->port.membase + UART010_CR); + cr &= ~UART010_CR_MSIE; + writel(cr, uap->port.membase + UART010_CR); +} + +static void pl010_enable_ms(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned int cr; + + cr = readb(uap->port.membase + UART010_CR); + cr |= UART010_CR_MSIE; + writel(cr, uap->port.membase + UART010_CR); +} + +static void pl010_rx_chars(struct uart_port *port) +{ + unsigned int status, rsr, max_count = 256; + u8 ch, flag; + + status = readb(port->membase + UART01x_FR); + while (UART_RX_DATA(status) && max_count--) { + ch = readb(port->membase + UART01x_DR); + flag = TTY_NORMAL; + + port->icount.rx++; + + /* + * Note that the error handling code is + * out of the main execution path + */ + rsr = readb(port->membase + UART01x_RSR) | UART_DUMMY_RSR_RX; + if (unlikely(rsr & UART01x_RSR_ANY)) { + writel(0, port->membase + UART01x_ECR); + + if (rsr & UART01x_RSR_BE) { + rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE); + port->icount.brk++; + if (uart_handle_break(port)) + goto ignore_char; + } else if (rsr & UART01x_RSR_PE) + port->icount.parity++; + else if (rsr & UART01x_RSR_FE) + port->icount.frame++; + if (rsr & UART01x_RSR_OE) + port->icount.overrun++; + + rsr &= port->read_status_mask; + + if (rsr & UART01x_RSR_BE) + flag = TTY_BREAK; + else if (rsr & UART01x_RSR_PE) + flag = TTY_PARITY; + else if (rsr & UART01x_RSR_FE) + flag = TTY_FRAME; + } + + if (uart_handle_sysrq_char(port, ch)) + goto ignore_char; + + uart_insert_char(port, rsr, UART01x_RSR_OE, ch, flag); + + ignore_char: + status = readb(port->membase + UART01x_FR); + } + tty_flip_buffer_push(&port->state->port); +} + +static void pl010_tx_chars(struct uart_port *port) +{ + u8 ch; + + uart_port_tx_limited(port, ch, port->fifosize >> 1, + true, + writel(ch, port->membase + UART01x_DR), + ({})); +} + +static void pl010_modem_status(struct uart_amba_port *uap) +{ + struct uart_port *port = &uap->port; + unsigned int status, delta; + + writel(0, port->membase + UART010_ICR); + + status = readb(port->membase + UART01x_FR) & UART01x_FR_MODEM_ANY; + + delta = status ^ uap->old_status; + uap->old_status = status; + + if (!delta) + return; + + if (delta & UART01x_FR_DCD) + uart_handle_dcd_change(port, status & UART01x_FR_DCD); + + if (delta & UART01x_FR_DSR) + port->icount.dsr++; + + if (delta & UART01x_FR_CTS) + uart_handle_cts_change(port, status & UART01x_FR_CTS); + + wake_up_interruptible(&port->state->port.delta_msr_wait); +} + +static irqreturn_t pl010_int(int irq, void *dev_id) +{ + struct uart_amba_port *uap = dev_id; + struct uart_port *port = &uap->port; + unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; + int handled = 0; + + spin_lock(&port->lock); + + status = readb(port->membase + UART010_IIR); + if (status) { + do { + if (status & (UART010_IIR_RTIS | UART010_IIR_RIS)) + pl010_rx_chars(port); + if (status & UART010_IIR_MIS) + pl010_modem_status(uap); + if (status & UART010_IIR_TIS) + pl010_tx_chars(port); + + if (pass_counter-- == 0) + break; + + status = readb(port->membase + UART010_IIR); + } while (status & (UART010_IIR_RTIS | UART010_IIR_RIS | + UART010_IIR_TIS)); + handled = 1; + } + + spin_unlock(&port->lock); + + return IRQ_RETVAL(handled); +} + +static unsigned int pl010_tx_empty(struct uart_port *port) +{ + unsigned int status = readb(port->membase + UART01x_FR); + + return status & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT; +} + +static unsigned int pl010_get_mctrl(struct uart_port *port) +{ + unsigned int result = 0; + unsigned int status; + + status = readb(port->membase + UART01x_FR); + if (status & UART01x_FR_DCD) + result |= TIOCM_CAR; + if (status & UART01x_FR_DSR) + result |= TIOCM_DSR; + if (status & UART01x_FR_CTS) + result |= TIOCM_CTS; + + return result; +} + +static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + if (uap->data) + uap->data->set_mctrl(uap->dev, port->membase, mctrl); +} + +static void pl010_break_ctl(struct uart_port *port, int break_state) +{ + unsigned long flags; + unsigned int lcr_h; + + spin_lock_irqsave(&port->lock, flags); + lcr_h = readb(port->membase + UART010_LCRH); + if (break_state == -1) + lcr_h |= UART01x_LCRH_BRK; + else + lcr_h &= ~UART01x_LCRH_BRK; + writel(lcr_h, port->membase + UART010_LCRH); + spin_unlock_irqrestore(&port->lock, flags); +} + +static int pl010_startup(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + int retval; + + /* + * Try to enable the clock producer. + */ + retval = clk_prepare_enable(uap->clk); + if (retval) + goto out; + + port->uartclk = clk_get_rate(uap->clk); + + /* + * Allocate the IRQ + */ + retval = request_irq(port->irq, pl010_int, 0, "uart-pl010", uap); + if (retval) + goto clk_dis; + + /* + * initialise the old status of the modem signals + */ + uap->old_status = readb(port->membase + UART01x_FR) & UART01x_FR_MODEM_ANY; + + /* + * Finally, enable interrupts + */ + writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE, + port->membase + UART010_CR); + + return 0; + + clk_dis: + clk_disable_unprepare(uap->clk); + out: + return retval; +} + +static void pl010_shutdown(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + /* + * Free the interrupt + */ + free_irq(port->irq, uap); + + /* + * disable all interrupts, disable the port + */ + writel(0, port->membase + UART010_CR); + + /* disable break condition and fifos */ + writel(readb(port->membase + UART010_LCRH) & + ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN), + port->membase + UART010_LCRH); + + /* + * Shut down the clock producer + */ + clk_disable_unprepare(uap->clk); +} + +static void +pl010_set_termios(struct uart_port *port, struct ktermios *termios, + const struct ktermios *old) +{ + unsigned int lcr_h, old_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); + quot = uart_get_divisor(port, baud); + + switch (termios->c_cflag & CSIZE) { + case CS5: + lcr_h = UART01x_LCRH_WLEN_5; + break; + case CS6: + lcr_h = UART01x_LCRH_WLEN_6; + break; + case CS7: + lcr_h = UART01x_LCRH_WLEN_7; + break; + default: // CS8 + lcr_h = UART01x_LCRH_WLEN_8; + break; + } + if (termios->c_cflag & CSTOPB) + lcr_h |= UART01x_LCRH_STP2; + if (termios->c_cflag & PARENB) { + lcr_h |= UART01x_LCRH_PEN; + if (!(termios->c_cflag & PARODD)) + lcr_h |= UART01x_LCRH_EPS; + } + if (port->fifosize > 1) + lcr_h |= UART01x_LCRH_FEN; + + spin_lock_irqsave(&port->lock, flags); + + /* + * Update the per-port timeout. + */ + uart_update_timeout(port, termios->c_cflag, baud); + + port->read_status_mask = UART01x_RSR_OE; + if (termios->c_iflag & INPCK) + port->read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE; + if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK)) + port->read_status_mask |= UART01x_RSR_BE; + + /* + * Characters to ignore + */ + port->ignore_status_mask = 0; + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE; + if (termios->c_iflag & IGNBRK) { + port->ignore_status_mask |= UART01x_RSR_BE; + /* + * If we're ignoring parity and break indicators, + * ignore overruns too (for real raw support). + */ + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= UART01x_RSR_OE; + } + + /* + * Ignore all characters if CREAD is not set. + */ + if ((termios->c_cflag & CREAD) == 0) + port->ignore_status_mask |= UART_DUMMY_RSR_RX; + + old_cr = readb(port->membase + UART010_CR) & ~UART010_CR_MSIE; + + if (UART_ENABLE_MS(port, termios->c_cflag)) + old_cr |= UART010_CR_MSIE; + + /* Set baud rate */ + quot -= 1; + writel((quot & 0xf00) >> 8, port->membase + UART010_LCRM); + writel(quot & 0xff, port->membase + UART010_LCRL); + + /* + * ----------v----------v----------v----------v----- + * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L + * ----------^----------^----------^----------^----- + */ + writel(lcr_h, port->membase + UART010_LCRH); + writel(old_cr, port->membase + UART010_CR); + + spin_unlock_irqrestore(&port->lock, flags); +} + +static void pl010_set_ldisc(struct uart_port *port, struct ktermios *termios) +{ + if (termios->c_line == N_PPS) { + port->flags |= UPF_HARDPPS_CD; + spin_lock_irq(&port->lock); + pl010_enable_ms(port); + spin_unlock_irq(&port->lock); + } else { + port->flags &= ~UPF_HARDPPS_CD; + if (!UART_ENABLE_MS(port, termios->c_cflag)) { + spin_lock_irq(&port->lock); + pl010_disable_ms(port); + spin_unlock_irq(&port->lock); + } + } +} + +static const char *pl010_type(struct uart_port *port) +{ + return port->type == PORT_AMBA ? "AMBA" : NULL; +} + +/* + * Release the memory region(s) being used by 'port' + */ +static void pl010_release_port(struct uart_port *port) +{ + release_mem_region(port->mapbase, UART_PORT_SIZE); +} + +/* + * Request the memory region(s) being used by 'port' + */ +static int pl010_request_port(struct uart_port *port) +{ + return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010") + != NULL ? 0 : -EBUSY; +} + +/* + * Configure/autoconfigure the port. + */ +static void pl010_config_port(struct uart_port *port, int flags) +{ + if (flags & UART_CONFIG_TYPE) { + port->type = PORT_AMBA; + pl010_request_port(port); + } +} + +/* + * verify the new serial_struct (for TIOCSSERIAL). + */ +static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser) +{ + int ret = 0; + if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA) + 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 amba_pl010_pops = { + .tx_empty = pl010_tx_empty, + .set_mctrl = pl010_set_mctrl, + .get_mctrl = pl010_get_mctrl, + .stop_tx = pl010_stop_tx, + .start_tx = pl010_start_tx, + .stop_rx = pl010_stop_rx, + .enable_ms = pl010_enable_ms, + .break_ctl = pl010_break_ctl, + .startup = pl010_startup, + .shutdown = pl010_shutdown, + .set_termios = pl010_set_termios, + .set_ldisc = pl010_set_ldisc, + .type = pl010_type, + .release_port = pl010_release_port, + .request_port = pl010_request_port, + .config_port = pl010_config_port, + .verify_port = pl010_verify_port, +}; + +static struct uart_amba_port *amba_ports[UART_NR]; + +#ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE + +static void pl010_console_putchar(struct uart_port *port, unsigned char ch) +{ + unsigned int status; + + do { + status = readb(port->membase + UART01x_FR); + barrier(); + } while (!UART_TX_READY(status)); + writel(ch, port->membase + UART01x_DR); +} + +static void +pl010_console_write(struct console *co, const char *s, unsigned int count) +{ + struct uart_amba_port *uap = amba_ports[co->index]; + struct uart_port *port = &uap->port; + unsigned int status, old_cr; + + clk_enable(uap->clk); + + /* + * First save the CR then disable the interrupts + */ + old_cr = readb(port->membase + UART010_CR); + writel(UART01x_CR_UARTEN, port->membase + UART010_CR); + + uart_console_write(port, s, count, pl010_console_putchar); + + /* + * Finally, wait for transmitter to become empty + * and restore the TCR + */ + do { + status = readb(port->membase + UART01x_FR); + barrier(); + } while (status & UART01x_FR_BUSY); + writel(old_cr, port->membase + UART010_CR); + + clk_disable(uap->clk); +} + +static void __init +pl010_console_get_options(struct uart_amba_port *uap, int *baud, + int *parity, int *bits) +{ + if (readb(uap->port.membase + UART010_CR) & UART01x_CR_UARTEN) { + unsigned int lcr_h, quot; + lcr_h = readb(uap->port.membase + UART010_LCRH); + + *parity = 'n'; + if (lcr_h & UART01x_LCRH_PEN) { + if (lcr_h & UART01x_LCRH_EPS) + *parity = 'e'; + else + *parity = 'o'; + } + + if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7) + *bits = 7; + else + *bits = 8; + + quot = readb(uap->port.membase + UART010_LCRL) | + readb(uap->port.membase + UART010_LCRM) << 8; + *baud = uap->port.uartclk / (16 * (quot + 1)); + } +} + +static int __init pl010_console_setup(struct console *co, char *options) +{ + struct uart_amba_port *uap; + int baud = 38400; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + int ret; + + /* + * 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 >= UART_NR) + co->index = 0; + uap = amba_ports[co->index]; + if (!uap) + return -ENODEV; + + ret = clk_prepare(uap->clk); + if (ret) + return ret; + + uap->port.uartclk = clk_get_rate(uap->clk); + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + else + pl010_console_get_options(uap, &baud, &parity, &bits); + + return uart_set_options(&uap->port, co, baud, parity, bits, flow); +} + +static struct uart_driver amba_reg; +static struct console amba_console = { + .name = "ttyAM", + .write = pl010_console_write, + .device = uart_console_device, + .setup = pl010_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &amba_reg, +}; + +#define AMBA_CONSOLE &amba_console +#else +#define AMBA_CONSOLE NULL +#endif + +static DEFINE_MUTEX(amba_reg_lock); +static struct uart_driver amba_reg = { + .owner = THIS_MODULE, + .driver_name = "ttyAM", + .dev_name = "ttyAM", + .major = SERIAL_AMBA_MAJOR, + .minor = SERIAL_AMBA_MINOR, + .nr = UART_NR, + .cons = AMBA_CONSOLE, +}; + +static int pl010_probe(struct amba_device *dev, const struct amba_id *id) +{ + struct uart_amba_port *uap; + void __iomem *base; + int i, ret; + + for (i = 0; i < ARRAY_SIZE(amba_ports); i++) + if (amba_ports[i] == NULL) + break; + + if (i == ARRAY_SIZE(amba_ports)) + return -EBUSY; + + uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port), + GFP_KERNEL); + if (!uap) + return -ENOMEM; + + base = devm_ioremap(&dev->dev, dev->res.start, + resource_size(&dev->res)); + if (!base) + return -ENOMEM; + + uap->clk = devm_clk_get(&dev->dev, NULL); + if (IS_ERR(uap->clk)) + return PTR_ERR(uap->clk); + + uap->port.dev = &dev->dev; + uap->port.mapbase = dev->res.start; + uap->port.membase = base; + uap->port.iotype = UPIO_MEM; + uap->port.irq = dev->irq[0]; + uap->port.fifosize = 16; + uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_AMBA_PL010_CONSOLE); + uap->port.ops = &amba_pl010_pops; + uap->port.flags = UPF_BOOT_AUTOCONF; + uap->port.line = i; + uap->dev = dev; + uap->data = dev_get_platdata(&dev->dev); + + amba_ports[i] = uap; + + amba_set_drvdata(dev, uap); + + mutex_lock(&amba_reg_lock); + if (!amba_reg.state) { + ret = uart_register_driver(&amba_reg); + if (ret < 0) { + mutex_unlock(&amba_reg_lock); + dev_err(uap->port.dev, + "Failed to register AMBA-PL010 driver\n"); + return ret; + } + } + mutex_unlock(&amba_reg_lock); + + ret = uart_add_one_port(&amba_reg, &uap->port); + if (ret) + amba_ports[i] = NULL; + + return ret; +} + +static void pl010_remove(struct amba_device *dev) +{ + struct uart_amba_port *uap = amba_get_drvdata(dev); + int i; + bool busy = false; + + uart_remove_one_port(&amba_reg, &uap->port); + + for (i = 0; i < ARRAY_SIZE(amba_ports); i++) + if (amba_ports[i] == uap) + amba_ports[i] = NULL; + else if (amba_ports[i]) + busy = true; + + if (!busy) + uart_unregister_driver(&amba_reg); +} + +#ifdef CONFIG_PM_SLEEP +static int pl010_suspend(struct device *dev) +{ + struct uart_amba_port *uap = dev_get_drvdata(dev); + + if (uap) + uart_suspend_port(&amba_reg, &uap->port); + + return 0; +} + +static int pl010_resume(struct device *dev) +{ + struct uart_amba_port *uap = dev_get_drvdata(dev); + + if (uap) + uart_resume_port(&amba_reg, &uap->port); + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(pl010_dev_pm_ops, pl010_suspend, pl010_resume); + +static const struct amba_id pl010_ids[] = { + { + .id = 0x00041010, + .mask = 0x000fffff, + }, + { 0, 0 }, +}; + +MODULE_DEVICE_TABLE(amba, pl010_ids); + +static struct amba_driver pl010_driver = { + .drv = { + .name = "uart-pl010", + .pm = &pl010_dev_pm_ops, + }, + .id_table = pl010_ids, + .probe = pl010_probe, + .remove = pl010_remove, +}; + +static int __init pl010_init(void) +{ + printk(KERN_INFO "Serial: AMBA driver\n"); + + return amba_driver_register(&pl010_driver); +} + +static void __exit pl010_exit(void) +{ + amba_driver_unregister(&pl010_driver); +} + +module_init(pl010_init); +module_exit(pl010_exit); + +MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd"); +MODULE_DESCRIPTION("ARM AMBA serial port driver"); +MODULE_LICENSE("GPL"); |