diff options
Diffstat (limited to 'drivers/tty/serial/sunplus-uart.c')
-rw-r--r-- | drivers/tty/serial/sunplus-uart.c | 775 |
1 files changed, 775 insertions, 0 deletions
diff --git a/drivers/tty/serial/sunplus-uart.c b/drivers/tty/serial/sunplus-uart.c new file mode 100644 index 000000000000..9f15922e681b --- /dev/null +++ b/drivers/tty/serial/sunplus-uart.c @@ -0,0 +1,775 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Sunplus SoC UART driver + * + * Author: Hammer Hsieh <hammerh0314@gmail.com> + * + * Note1: This driver is 8250-like uart, but are not register compatible. + * + * Note2: On some buses, for preventing data incoherence, must do a read + * for ensure write made it to hardware. In this driver, function startup + * and shutdown did not do a read but only do a write directly. For what? + * In Sunplus bus communication between memory bus and peripheral bus with + * posted write, it will send a specific command after last write command + * to make sure write done. Then memory bus identify the specific command + * and send done signal back to master device. After master device received + * done signal, then proceed next write command. It is no need to do a read + * before write. + */ +#include <linux/clk.h> +#include <linux/console.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/reset.h> +#include <linux/serial_core.h> +#include <linux/serial_reg.h> +#include <linux/sysrq.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <asm/irq.h> + +/* Register offsets */ +#define SUP_UART_DATA 0x00 +#define SUP_UART_LSR 0x04 +#define SUP_UART_MSR 0x08 +#define SUP_UART_LCR 0x0C +#define SUP_UART_MCR 0x10 +#define SUP_UART_DIV_L 0x14 +#define SUP_UART_DIV_H 0x18 +#define SUP_UART_ISC 0x1C +#define SUP_UART_TX_RESIDUE 0x20 +#define SUP_UART_RX_RESIDUE 0x24 + +/* Line Status Register bits */ +#define SUP_UART_LSR_BC BIT(5) /* break condition status */ +#define SUP_UART_LSR_FE BIT(4) /* frame error status */ +#define SUP_UART_LSR_OE BIT(3) /* overrun error status */ +#define SUP_UART_LSR_PE BIT(2) /* parity error status */ +#define SUP_UART_LSR_RX BIT(1) /* 1: receive fifo not empty */ +#define SUP_UART_LSR_TX BIT(0) /* 1: transmit fifo is not full */ +#define SUP_UART_LSR_TX_NOT_FULL 1 +#define SUP_UART_LSR_BRK_ERROR_BITS GENMASK(5, 2) + +/* Line Control Register bits */ +#define SUP_UART_LCR_SBC BIT(5) /* select break condition */ + +/* Modem Control Register bits */ +#define SUP_UART_MCR_RI BIT(3) /* ring indicator */ +#define SUP_UART_MCR_DCD BIT(2) /* data carrier detect */ + +/* Interrupt Status/Control Register bits */ +#define SUP_UART_ISC_RXM BIT(5) /* RX interrupt enable */ +#define SUP_UART_ISC_TXM BIT(4) /* TX interrupt enable */ +#define SUP_UART_ISC_RX BIT(1) /* RX interrupt status */ +#define SUP_UART_ISC_TX BIT(0) /* TX interrupt status */ + +#define SUP_DUMMY_READ BIT(16) /* drop bytes received on a !CREAD port */ +#define SUP_UART_NR 5 + +struct sunplus_uart_port { + struct uart_port port; + struct clk *clk; + struct reset_control *rstc; +}; + +static void sp_uart_put_char(struct uart_port *port, unsigned int ch) +{ + writel(ch, port->membase + SUP_UART_DATA); +} + +static u32 sunplus_tx_buf_not_full(struct uart_port *port) +{ + unsigned int lsr = readl(port->membase + SUP_UART_LSR); + + return (lsr & SUP_UART_LSR_TX) ? SUP_UART_LSR_TX_NOT_FULL : 0; +} + +static unsigned int sunplus_tx_empty(struct uart_port *port) +{ + unsigned int lsr = readl(port->membase + SUP_UART_LSR); + + return (lsr & UART_LSR_TEMT) ? TIOCSER_TEMT : 0; +} + +static void sunplus_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + unsigned int mcr = readl(port->membase + SUP_UART_MCR); + + if (mctrl & TIOCM_DTR) + mcr |= UART_MCR_DTR; + else + mcr &= ~UART_MCR_DTR; + + if (mctrl & TIOCM_RTS) + mcr |= UART_MCR_RTS; + else + mcr &= ~UART_MCR_RTS; + + if (mctrl & TIOCM_CAR) + mcr |= SUP_UART_MCR_DCD; + else + mcr &= ~SUP_UART_MCR_DCD; + + if (mctrl & TIOCM_RI) + mcr |= SUP_UART_MCR_RI; + else + mcr &= ~SUP_UART_MCR_RI; + + if (mctrl & TIOCM_LOOP) + mcr |= UART_MCR_LOOP; + else + mcr &= ~UART_MCR_LOOP; + + writel(mcr, port->membase + SUP_UART_MCR); +} + +static unsigned int sunplus_get_mctrl(struct uart_port *port) +{ + unsigned int mcr, ret = 0; + + mcr = readl(port->membase + SUP_UART_MCR); + + if (mcr & UART_MCR_DTR) + ret |= TIOCM_DTR; + + if (mcr & UART_MCR_RTS) + ret |= TIOCM_RTS; + + if (mcr & SUP_UART_MCR_DCD) + ret |= TIOCM_CAR; + + if (mcr & SUP_UART_MCR_RI) + ret |= TIOCM_RI; + + if (mcr & UART_MCR_LOOP) + ret |= TIOCM_LOOP; + + return ret; +} + +static void sunplus_stop_tx(struct uart_port *port) +{ + unsigned int isc; + + isc = readl(port->membase + SUP_UART_ISC); + isc &= ~SUP_UART_ISC_TXM; + writel(isc, port->membase + SUP_UART_ISC); +} + +static void sunplus_start_tx(struct uart_port *port) +{ + unsigned int isc; + + isc = readl(port->membase + SUP_UART_ISC); + isc |= SUP_UART_ISC_TXM; + writel(isc, port->membase + SUP_UART_ISC); +} + +static void sunplus_stop_rx(struct uart_port *port) +{ + unsigned int isc; + + isc = readl(port->membase + SUP_UART_ISC); + isc &= ~SUP_UART_ISC_RXM; + writel(isc, port->membase + SUP_UART_ISC); +} + +static void sunplus_break_ctl(struct uart_port *port, int ctl) +{ + unsigned long flags; + unsigned int lcr; + + spin_lock_irqsave(&port->lock, flags); + + lcr = readl(port->membase + SUP_UART_LCR); + + if (ctl) + lcr |= SUP_UART_LCR_SBC; /* start break */ + else + lcr &= ~SUP_UART_LCR_SBC; /* stop break */ + + writel(lcr, port->membase + SUP_UART_LCR); + + spin_unlock_irqrestore(&port->lock, flags); +} + +static void transmit_chars(struct uart_port *port) +{ + struct circ_buf *xmit = &port->state->xmit; + + if (port->x_char) { + sp_uart_put_char(port, port->x_char); + port->icount.tx++; + port->x_char = 0; + return; + } + + if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { + sunplus_stop_tx(port); + return; + } + + do { + sp_uart_put_char(port, xmit->buf[xmit->tail]); + xmit->tail = (xmit->tail + 1) % UART_XMIT_SIZE; + port->icount.tx++; + + if (uart_circ_empty(xmit)) + break; + } while (sunplus_tx_buf_not_full(port)); + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(port); + + if (uart_circ_empty(xmit)) + sunplus_stop_tx(port); +} + +static void receive_chars(struct uart_port *port) +{ + unsigned int lsr = readl(port->membase + SUP_UART_LSR); + unsigned int ch, flag; + + do { + ch = readl(port->membase + SUP_UART_DATA); + flag = TTY_NORMAL; + port->icount.rx++; + + if (unlikely(lsr & SUP_UART_LSR_BRK_ERROR_BITS)) { + if (lsr & SUP_UART_LSR_BC) { + lsr &= ~(SUP_UART_LSR_FE | SUP_UART_LSR_PE); + port->icount.brk++; + flag = TTY_BREAK; + if (uart_handle_break(port)) + goto ignore_char; + } else if (lsr & SUP_UART_LSR_PE) { + port->icount.parity++; + flag = TTY_PARITY; + } else if (lsr & SUP_UART_LSR_FE) { + port->icount.frame++; + flag = TTY_FRAME; + } + + if (lsr & SUP_UART_LSR_OE) + port->icount.overrun++; + } + + if (port->ignore_status_mask & SUP_DUMMY_READ) + goto ignore_char; + + if (uart_handle_sysrq_char(port, ch)) + goto ignore_char; + + uart_insert_char(port, lsr, SUP_UART_LSR_OE, ch, flag); + +ignore_char: + lsr = readl(port->membase + SUP_UART_LSR); + } while (lsr & SUP_UART_LSR_RX); + + tty_flip_buffer_push(&port->state->port); +} + +static irqreturn_t sunplus_uart_irq(int irq, void *args) +{ + struct uart_port *port = args; + unsigned int isc; + + spin_lock(&port->lock); + + isc = readl(port->membase + SUP_UART_ISC); + + if (isc & SUP_UART_ISC_RX) + receive_chars(port); + + if (isc & SUP_UART_ISC_TX) + transmit_chars(port); + + spin_unlock(&port->lock); + + return IRQ_HANDLED; +} + +static int sunplus_startup(struct uart_port *port) +{ + unsigned long flags; + unsigned int isc = 0; + int ret; + + ret = request_irq(port->irq, sunplus_uart_irq, 0, "sunplus_uart", port); + if (ret) + return ret; + + spin_lock_irqsave(&port->lock, flags); + /* isc define Bit[7:4] int setting, Bit[3:0] int status + * isc register will clean Bit[3:0] int status after read + * only do a write to Bit[7:4] int setting + */ + isc |= SUP_UART_ISC_RXM; + writel(isc, port->membase + SUP_UART_ISC); + spin_unlock_irqrestore(&port->lock, flags); + + return 0; +} + +static void sunplus_shutdown(struct uart_port *port) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + /* isc define Bit[7:4] int setting, Bit[3:0] int status + * isc register will clean Bit[3:0] int status after read + * only do a write to Bit[7:4] int setting + */ + writel(0, port->membase + SUP_UART_ISC); /* disable all interrupt */ + spin_unlock_irqrestore(&port->lock, flags); + + free_irq(port->irq, port); +} + +static void sunplus_set_termios(struct uart_port *port, + struct ktermios *termios, + struct ktermios *oldtermios) +{ + u32 ext, div, div_l, div_h, baud, lcr; + u32 clk = port->uartclk; + unsigned long flags; + + baud = uart_get_baud_rate(port, termios, oldtermios, 0, port->uartclk / 16); + + /* baud rate = uartclk / ((16 * divisor + 1) + divisor_ext) */ + clk += baud >> 1; + div = clk / baud; + ext = div & 0x0F; + div = (div >> 4) - 1; + div_l = (div & 0xFF) | (ext << 12); + div_h = div >> 8; + + switch (termios->c_cflag & CSIZE) { + case CS5: + lcr = UART_LCR_WLEN5; + break; + case CS6: + lcr = UART_LCR_WLEN6; + break; + case CS7: + lcr = UART_LCR_WLEN7; + break; + default: + lcr = UART_LCR_WLEN8; + break; + } + + if (termios->c_cflag & CSTOPB) + lcr |= UART_LCR_STOP; + + if (termios->c_cflag & PARENB) { + lcr |= UART_LCR_PARITY; + + if (!(termios->c_cflag & PARODD)) + lcr |= UART_LCR_EPAR; + } + + spin_lock_irqsave(&port->lock, flags); + + uart_update_timeout(port, termios->c_cflag, baud); + + port->read_status_mask = 0; + if (termios->c_iflag & INPCK) + port->read_status_mask |= SUP_UART_LSR_PE | SUP_UART_LSR_FE; + + if (termios->c_iflag & (BRKINT | PARMRK)) + port->read_status_mask |= SUP_UART_LSR_BC; + + /* Characters to ignore */ + port->ignore_status_mask = 0; + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= SUP_UART_LSR_FE | SUP_UART_LSR_PE; + + if (termios->c_iflag & IGNBRK) { + port->ignore_status_mask |= SUP_UART_LSR_BC; + + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= SUP_UART_LSR_OE; + } + + /* Ignore all characters if CREAD is not set */ + if ((termios->c_cflag & CREAD) == 0) { + port->ignore_status_mask |= SUP_DUMMY_READ; + /* flush rx data FIFO */ + writel(0, port->membase + SUP_UART_RX_RESIDUE); + } + + /* Settings for baud rate divisor and lcr */ + writel(div_h, port->membase + SUP_UART_DIV_H); + writel(div_l, port->membase + SUP_UART_DIV_L); + writel(lcr, port->membase + SUP_UART_LCR); + + spin_unlock_irqrestore(&port->lock, flags); +} + +static void sunplus_set_ldisc(struct uart_port *port, struct ktermios *termios) +{ + int new = termios->c_line; + + if (new == N_PPS) + port->flags |= UPF_HARDPPS_CD; + else + port->flags &= ~UPF_HARDPPS_CD; +} + +static const char *sunplus_type(struct uart_port *port) +{ + return port->type == PORT_SUNPLUS ? "sunplus_uart" : NULL; +} + +static void sunplus_config_port(struct uart_port *port, int type) +{ + if (type & UART_CONFIG_TYPE) + port->type = PORT_SUNPLUS; +} + +static int sunplus_verify_port(struct uart_port *port, struct serial_struct *ser) +{ + if (ser->type != PORT_UNKNOWN && ser->type != PORT_SUNPLUS) + return -EINVAL; + + return 0; +} + +#if defined(CONFIG_SERIAL_SUNPLUS_CONSOLE) || defined(CONFIG_CONSOLE_POLL) +static void wait_for_xmitr(struct uart_port *port) +{ + unsigned int val; + int ret; + + /* Wait while FIFO is full or timeout */ + ret = readl_poll_timeout_atomic(port->membase + SUP_UART_LSR, val, + (val & SUP_UART_LSR_TX), 1, 10000); + + if (ret == -ETIMEDOUT) { + dev_err(port->dev, "Timeout waiting while UART TX FULL\n"); + return; + } +} +#endif + +#ifdef CONFIG_CONSOLE_POLL +static void sunplus_poll_put_char(struct uart_port *port, unsigned char data) +{ + wait_for_xmitr(port); + sp_uart_put_char(port, data); +} + +static int sunplus_poll_get_char(struct uart_port *port) +{ + unsigned int lsr = readl(port->membase + SUP_UART_LSR); + + if (!(lsr & SUP_UART_LSR_RX)) + return NO_POLL_CHAR; + + return readl(port->membase + SUP_UART_DATA); +} +#endif + +static const struct uart_ops sunplus_uart_ops = { + .tx_empty = sunplus_tx_empty, + .set_mctrl = sunplus_set_mctrl, + .get_mctrl = sunplus_get_mctrl, + .stop_tx = sunplus_stop_tx, + .start_tx = sunplus_start_tx, + .stop_rx = sunplus_stop_rx, + .break_ctl = sunplus_break_ctl, + .startup = sunplus_startup, + .shutdown = sunplus_shutdown, + .set_termios = sunplus_set_termios, + .set_ldisc = sunplus_set_ldisc, + .type = sunplus_type, + .config_port = sunplus_config_port, + .verify_port = sunplus_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_put_char = sunplus_poll_put_char, + .poll_get_char = sunplus_poll_get_char, +#endif +}; + +#ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE +struct sunplus_uart_port *sunplus_console_ports[SUP_UART_NR]; + +static void sunplus_uart_console_putchar(struct uart_port *port, + unsigned char ch) +{ + wait_for_xmitr(port); + sp_uart_put_char(port, ch); +} + +static void sunplus_console_write(struct console *co, + const char *s, + unsigned int count) +{ + unsigned long flags; + int locked = 1; + + local_irq_save(flags); + + if (sunplus_console_ports[co->index]->port.sysrq) + locked = 0; + else if (oops_in_progress) + locked = spin_trylock(&sunplus_console_ports[co->index]->port.lock); + else + spin_lock(&sunplus_console_ports[co->index]->port.lock); + + uart_console_write(&sunplus_console_ports[co->index]->port, s, count, + sunplus_uart_console_putchar); + + if (locked) + spin_unlock(&sunplus_console_ports[co->index]->port.lock); + + local_irq_restore(flags); +} + +static int __init sunplus_console_setup(struct console *co, char *options) +{ + struct sunplus_uart_port *sup; + int baud = 115200; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + + if (co->index < 0 || co->index >= SUP_UART_NR) + return -EINVAL; + + sup = sunplus_console_ports[co->index]; + if (!sup) + return -ENODEV; + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + + return uart_set_options(&sup->port, co, baud, parity, bits, flow); +} + +static struct uart_driver sunplus_uart_driver; +static struct console sunplus_uart_console = { + .name = "ttySUP", + .write = sunplus_console_write, + .device = uart_console_device, + .setup = sunplus_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &sunplus_uart_driver +}; + +#define SERIAL_SUNPLUS_CONSOLE (&sunplus_uart_console) +#else +#define SERIAL_SUNPLUS_CONSOLE NULL +#endif + +static struct uart_driver sunplus_uart_driver = { + .owner = THIS_MODULE, + .driver_name = "sunplus_uart", + .dev_name = "ttySUP", + .major = TTY_MAJOR, + .minor = 64, + .nr = SUP_UART_NR, + .cons = SERIAL_SUNPLUS_CONSOLE, +}; + +static void sunplus_uart_disable_unprepare(void *data) +{ + clk_disable_unprepare(data); +} + +static void sunplus_uart_reset_control_assert(void *data) +{ + reset_control_assert(data); +} + +static int sunplus_uart_probe(struct platform_device *pdev) +{ + struct sunplus_uart_port *sup; + struct uart_port *port; + struct resource *res; + int ret, irq; + + pdev->id = of_alias_get_id(pdev->dev.of_node, "serial"); + + if (pdev->id < 0 || pdev->id >= SUP_UART_NR) + return -EINVAL; + + sup = devm_kzalloc(&pdev->dev, sizeof(*sup), GFP_KERNEL); + if (!sup) + return -ENOMEM; + + sup->clk = devm_clk_get_optional(&pdev->dev, NULL); + if (IS_ERR(sup->clk)) + return dev_err_probe(&pdev->dev, PTR_ERR(sup->clk), "clk not found\n"); + + ret = clk_prepare_enable(sup->clk); + if (ret) + return ret; + + ret = devm_add_action_or_reset(&pdev->dev, sunplus_uart_disable_unprepare, sup->clk); + if (ret) + return ret; + + sup->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL); + if (IS_ERR(sup->rstc)) + return dev_err_probe(&pdev->dev, PTR_ERR(sup->rstc), "rstc not found\n"); + + port = &sup->port; + + port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(port->membase)) + return dev_err_probe(&pdev->dev, PTR_ERR(port->membase), "membase not found\n"); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + port->mapbase = res->start; + port->uartclk = clk_get_rate(sup->clk); + port->line = pdev->id; + port->irq = irq; + port->dev = &pdev->dev; + port->iotype = UPIO_MEM; + port->ops = &sunplus_uart_ops; + port->flags = UPF_BOOT_AUTOCONF; + port->fifosize = 128; + + ret = reset_control_deassert(sup->rstc); + if (ret) + return ret; + + ret = devm_add_action_or_reset(&pdev->dev, sunplus_uart_reset_control_assert, sup->rstc); + if (ret) + return ret; + +#ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE + sunplus_console_ports[sup->port.line] = sup; +#endif + + platform_set_drvdata(pdev, &sup->port); + + ret = uart_add_one_port(&sunplus_uart_driver, &sup->port); +#ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE + if (ret) + sunplus_console_ports[sup->port.line] = NULL; +#endif + + return ret; +} + +static int sunplus_uart_remove(struct platform_device *pdev) +{ + struct sunplus_uart_port *sup = platform_get_drvdata(pdev); + + uart_remove_one_port(&sunplus_uart_driver, &sup->port); + + return 0; +} + +static int __maybe_unused sunplus_uart_suspend(struct device *dev) +{ + struct sunplus_uart_port *sup = dev_get_drvdata(dev); + + if (!uart_console(&sup->port)) + uart_suspend_port(&sunplus_uart_driver, &sup->port); + + return 0; +} + +static int __maybe_unused sunplus_uart_resume(struct device *dev) +{ + struct sunplus_uart_port *sup = dev_get_drvdata(dev); + + if (!uart_console(&sup->port)) + uart_resume_port(&sunplus_uart_driver, &sup->port); + + return 0; +} + +static const struct dev_pm_ops sunplus_uart_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(sunplus_uart_suspend, sunplus_uart_resume) +}; + +static const struct of_device_id sp_uart_of_match[] = { + { .compatible = "sunplus,sp7021-uart" }, + {} +}; +MODULE_DEVICE_TABLE(of, sp_uart_of_match); + +static struct platform_driver sunplus_uart_platform_driver = { + .probe = sunplus_uart_probe, + .remove = sunplus_uart_remove, + .driver = { + .name = "sunplus_uart", + .of_match_table = sp_uart_of_match, + .pm = &sunplus_uart_pm_ops, + } +}; + +static int __init sunplus_uart_init(void) +{ + int ret; + + ret = uart_register_driver(&sunplus_uart_driver); + if (ret) + return ret; + + ret = platform_driver_register(&sunplus_uart_platform_driver); + if (ret) + uart_unregister_driver(&sunplus_uart_driver); + + return ret; +} +module_init(sunplus_uart_init); + +static void __exit sunplus_uart_exit(void) +{ + platform_driver_unregister(&sunplus_uart_platform_driver); + uart_unregister_driver(&sunplus_uart_driver); +} +module_exit(sunplus_uart_exit); + +#ifdef CONFIG_SERIAL_EARLYCON +static void sunplus_uart_putc(struct uart_port *port, unsigned char c) +{ + unsigned int val; + int ret; + + ret = readl_poll_timeout_atomic(port->membase + SUP_UART_LSR, val, + (val & UART_LSR_TEMT), 1, 10000); + if (ret) + return; + + writel(c, port->membase + SUP_UART_DATA); +} + +static void sunplus_uart_early_write(struct console *con, const char *s, unsigned int n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, sunplus_uart_putc); +} + +static int __init +sunplus_uart_early_setup(struct earlycon_device *dev, const char *opt) +{ + if (!(dev->port.membase || dev->port.iobase)) + return -ENODEV; + + dev->con->write = sunplus_uart_early_write; + + return 0; +} +OF_EARLYCON_DECLARE(sunplus_uart, "sunplus,sp7021-uart", sunplus_uart_early_setup); +#endif + +MODULE_DESCRIPTION("Sunplus UART driver"); +MODULE_AUTHOR("Hammer Hsieh <hammerh0314@gmail.com>"); +MODULE_LICENSE("GPL v2"); |