/* * Copyright (C) 2012-2015 Spreadtrum Communications Inc. * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and * may be copied, distributed, and modified under those terms. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #if defined(CONFIG_SERIAL_SPRD_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) #define SUPPORT_SYSRQ #endif #include <linux/clk.h> #include <linux/console.h> #include <linux/delay.h> #include <linux/io.h> #include <linux/ioport.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/serial_core.h> #include <linux/serial.h> #include <linux/slab.h> #include <linux/tty.h> #include <linux/tty_flip.h> /* device name */ #define UART_NR_MAX 8 #define SPRD_TTY_NAME "ttyS" #define SPRD_FIFO_SIZE 128 #define SPRD_DEF_RATE 26000000 #define SPRD_BAUD_IO_LIMIT 3000000 #define SPRD_TIMEOUT 256 /* the offset of serial registers and BITs for them */ /* data registers */ #define SPRD_TXD 0x0000 #define SPRD_RXD 0x0004 /* line status register and its BITs */ #define SPRD_LSR 0x0008 #define SPRD_LSR_OE BIT(4) #define SPRD_LSR_FE BIT(3) #define SPRD_LSR_PE BIT(2) #define SPRD_LSR_BI BIT(7) #define SPRD_LSR_TX_OVER BIT(15) /* data number in TX and RX fifo */ #define SPRD_STS1 0x000C /* interrupt enable register and its BITs */ #define SPRD_IEN 0x0010 #define SPRD_IEN_RX_FULL BIT(0) #define SPRD_IEN_TX_EMPTY BIT(1) #define SPRD_IEN_BREAK_DETECT BIT(7) #define SPRD_IEN_TIMEOUT BIT(13) /* interrupt clear register */ #define SPRD_ICLR 0x0014 /* line control register */ #define SPRD_LCR 0x0018 #define SPRD_LCR_STOP_1BIT 0x10 #define SPRD_LCR_STOP_2BIT 0x30 #define SPRD_LCR_DATA_LEN (BIT(2) | BIT(3)) #define SPRD_LCR_DATA_LEN5 0x0 #define SPRD_LCR_DATA_LEN6 0x4 #define SPRD_LCR_DATA_LEN7 0x8 #define SPRD_LCR_DATA_LEN8 0xc #define SPRD_LCR_PARITY (BIT(0) | BIT(1)) #define SPRD_LCR_PARITY_EN 0x2 #define SPRD_LCR_EVEN_PAR 0x0 #define SPRD_LCR_ODD_PAR 0x1 /* control register 1 */ #define SPRD_CTL1 0x001C #define RX_HW_FLOW_CTL_THLD BIT(6) #define RX_HW_FLOW_CTL_EN BIT(7) #define TX_HW_FLOW_CTL_EN BIT(8) #define RX_TOUT_THLD_DEF 0x3E00 #define RX_HFC_THLD_DEF 0x40 /* fifo threshold register */ #define SPRD_CTL2 0x0020 #define THLD_TX_EMPTY 0x40 #define THLD_RX_FULL 0x40 /* config baud rate register */ #define SPRD_CLKD0 0x0024 #define SPRD_CLKD1 0x0028 /* interrupt mask status register */ #define SPRD_IMSR 0x002C #define SPRD_IMSR_RX_FIFO_FULL BIT(0) #define SPRD_IMSR_TX_FIFO_EMPTY BIT(1) #define SPRD_IMSR_BREAK_DETECT BIT(7) #define SPRD_IMSR_TIMEOUT BIT(13) struct reg_backup { u32 ien; u32 ctrl0; u32 ctrl1; u32 ctrl2; u32 clkd0; u32 clkd1; u32 dspwait; }; struct sprd_uart_port { struct uart_port port; struct reg_backup reg_bak; char name[16]; }; static struct sprd_uart_port *sprd_port[UART_NR_MAX]; static int sprd_ports_num; static inline unsigned int serial_in(struct uart_port *port, int offset) { return readl_relaxed(port->membase + offset); } static inline void serial_out(struct uart_port *port, int offset, int value) { writel_relaxed(value, port->membase + offset); } static unsigned int sprd_tx_empty(struct uart_port *port) { if (serial_in(port, SPRD_STS1) & 0xff00) return 0; else return TIOCSER_TEMT; } static unsigned int sprd_get_mctrl(struct uart_port *port) { return TIOCM_DSR | TIOCM_CTS; } static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl) { /* nothing to do */ } static void sprd_stop_tx(struct uart_port *port) { unsigned int ien, iclr; iclr = serial_in(port, SPRD_ICLR); ien = serial_in(port, SPRD_IEN); iclr |= SPRD_IEN_TX_EMPTY; ien &= ~SPRD_IEN_TX_EMPTY; serial_out(port, SPRD_ICLR, iclr); serial_out(port, SPRD_IEN, ien); } static void sprd_start_tx(struct uart_port *port) { unsigned int ien; ien = serial_in(port, SPRD_IEN); if (!(ien & SPRD_IEN_TX_EMPTY)) { ien |= SPRD_IEN_TX_EMPTY; serial_out(port, SPRD_IEN, ien); } } static void sprd_stop_rx(struct uart_port *port) { unsigned int ien, iclr; iclr = serial_in(port, SPRD_ICLR); ien = serial_in(port, SPRD_IEN); ien &= ~(SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT); iclr |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT; serial_out(port, SPRD_IEN, ien); serial_out(port, SPRD_ICLR, iclr); } /* The Sprd serial does not support this function. */ static void sprd_break_ctl(struct uart_port *port, int break_state) { /* nothing to do */ } static int handle_lsr_errors(struct uart_port *port, unsigned int *flag, unsigned int *lsr) { int ret = 0; /* statistics */ if (*lsr & SPRD_LSR_BI) { *lsr &= ~(SPRD_LSR_FE | SPRD_LSR_PE); port->icount.brk++; ret = uart_handle_break(port); if (ret) return ret; } else if (*lsr & SPRD_LSR_PE) port->icount.parity++; else if (*lsr & SPRD_LSR_FE) port->icount.frame++; if (*lsr & SPRD_LSR_OE) port->icount.overrun++; /* mask off conditions which should be ignored */ *lsr &= port->read_status_mask; if (*lsr & SPRD_LSR_BI) *flag = TTY_BREAK; else if (*lsr & SPRD_LSR_PE) *flag = TTY_PARITY; else if (*lsr & SPRD_LSR_FE) *flag = TTY_FRAME; return ret; } static inline void sprd_rx(struct uart_port *port) { struct tty_port *tty = &port->state->port; unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT; while ((serial_in(port, SPRD_STS1) & 0x00ff) && max_count--) { lsr = serial_in(port, SPRD_LSR); ch = serial_in(port, SPRD_RXD); flag = TTY_NORMAL; port->icount.rx++; if (lsr & (SPRD_LSR_BI | SPRD_LSR_PE | SPRD_LSR_FE | SPRD_LSR_OE)) if (handle_lsr_errors(port, &lsr, &flag)) continue; if (uart_handle_sysrq_char(port, ch)) continue; uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag); } tty_flip_buffer_push(tty); } static inline void sprd_tx(struct uart_port *port) { struct circ_buf *xmit = &port->state->xmit; int count; if (port->x_char) { serial_out(port, SPRD_TXD, port->x_char); port->icount.tx++; port->x_char = 0; return; } if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { sprd_stop_tx(port); return; } count = THLD_TX_EMPTY; do { serial_out(port, SPRD_TXD, 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)) sprd_stop_tx(port); } /* this handles the interrupt from one port */ static irqreturn_t sprd_handle_irq(int irq, void *dev_id) { struct uart_port *port = dev_id; unsigned int ims; spin_lock(&port->lock); ims = serial_in(port, SPRD_IMSR); if (!ims) { spin_unlock(&port->lock); return IRQ_NONE; } serial_out(port, SPRD_ICLR, ~0); if (ims & (SPRD_IMSR_RX_FIFO_FULL | SPRD_IMSR_BREAK_DETECT | SPRD_IMSR_TIMEOUT)) sprd_rx(port); if (ims & SPRD_IMSR_TX_FIFO_EMPTY) sprd_tx(port); spin_unlock(&port->lock); return IRQ_HANDLED; } static int sprd_startup(struct uart_port *port) { int ret = 0; unsigned int ien, fc; unsigned int timeout; struct sprd_uart_port *sp; unsigned long flags; serial_out(port, SPRD_CTL2, ((THLD_TX_EMPTY << 8) | THLD_RX_FULL)); /* clear rx fifo */ timeout = SPRD_TIMEOUT; while (timeout-- && serial_in(port, SPRD_STS1) & 0x00ff) serial_in(port, SPRD_RXD); /* clear tx fifo */ timeout = SPRD_TIMEOUT; while (timeout-- && serial_in(port, SPRD_STS1) & 0xff00) cpu_relax(); /* clear interrupt */ serial_out(port, SPRD_IEN, 0); serial_out(port, SPRD_ICLR, ~0); /* allocate irq */ sp = container_of(port, struct sprd_uart_port, port); snprintf(sp->name, sizeof(sp->name), "sprd_serial%d", port->line); ret = devm_request_irq(port->dev, port->irq, sprd_handle_irq, IRQF_SHARED, sp->name, port); if (ret) { dev_err(port->dev, "fail to request serial irq %d, ret=%d\n", port->irq, ret); return ret; } fc = serial_in(port, SPRD_CTL1); fc |= RX_TOUT_THLD_DEF | RX_HFC_THLD_DEF; serial_out(port, SPRD_CTL1, fc); /* enable interrupt */ spin_lock_irqsave(&port->lock, flags); ien = serial_in(port, SPRD_IEN); ien |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT | SPRD_IEN_TIMEOUT; serial_out(port, SPRD_IEN, ien); spin_unlock_irqrestore(&port->lock, flags); return 0; } static void sprd_shutdown(struct uart_port *port) { serial_out(port, SPRD_IEN, 0); serial_out(port, SPRD_ICLR, ~0); devm_free_irq(port->dev, port->irq, port); } static void sprd_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { unsigned int baud, quot; unsigned int lcr = 0, fc; unsigned long flags; /* ask the core to calculate the divisor for us */ baud = uart_get_baud_rate(port, termios, old, 0, SPRD_BAUD_IO_LIMIT); quot = (unsigned int)((port->uartclk + baud / 2) / baud); /* set data length */ switch (termios->c_cflag & CSIZE) { case CS5: lcr |= SPRD_LCR_DATA_LEN5; break; case CS6: lcr |= SPRD_LCR_DATA_LEN6; break; case CS7: lcr |= SPRD_LCR_DATA_LEN7; break; case CS8: default: lcr |= SPRD_LCR_DATA_LEN8; break; } /* calculate stop bits */ lcr &= ~(SPRD_LCR_STOP_1BIT | SPRD_LCR_STOP_2BIT); if (termios->c_cflag & CSTOPB) lcr |= SPRD_LCR_STOP_2BIT; else lcr |= SPRD_LCR_STOP_1BIT; /* calculate parity */ lcr &= ~SPRD_LCR_PARITY; termios->c_cflag &= ~CMSPAR; /* no support mark/space */ if (termios->c_cflag & PARENB) { lcr |= SPRD_LCR_PARITY_EN; if (termios->c_cflag & PARODD) lcr |= SPRD_LCR_ODD_PAR; else lcr |= SPRD_LCR_EVEN_PAR; } spin_lock_irqsave(&port->lock, flags); /* update the per-port timeout */ uart_update_timeout(port, termios->c_cflag, baud); port->read_status_mask = SPRD_LSR_OE; if (termios->c_iflag & INPCK) port->read_status_mask |= SPRD_LSR_FE | SPRD_LSR_PE; if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK)) port->read_status_mask |= SPRD_LSR_BI; /* characters to ignore */ port->ignore_status_mask = 0; if (termios->c_iflag & IGNPAR) port->ignore_status_mask |= SPRD_LSR_PE | SPRD_LSR_FE; if (termios->c_iflag & IGNBRK) { port->ignore_status_mask |= SPRD_LSR_BI; /* * If we're ignoring parity and break indicators, * ignore overruns too (for real raw support). */ if (termios->c_iflag & IGNPAR) port->ignore_status_mask |= SPRD_LSR_OE; } /* flow control */ fc = serial_in(port, SPRD_CTL1); fc &= ~(RX_HW_FLOW_CTL_THLD | RX_HW_FLOW_CTL_EN | TX_HW_FLOW_CTL_EN); if (termios->c_cflag & CRTSCTS) { fc |= RX_HW_FLOW_CTL_THLD; fc |= RX_HW_FLOW_CTL_EN; fc |= TX_HW_FLOW_CTL_EN; } /* clock divider bit0~bit15 */ serial_out(port, SPRD_CLKD0, quot & 0xffff); /* clock divider bit16~bit20 */ serial_out(port, SPRD_CLKD1, (quot & 0x1f0000) >> 16); serial_out(port, SPRD_LCR, lcr); fc |= RX_TOUT_THLD_DEF | RX_HFC_THLD_DEF; serial_out(port, SPRD_CTL1, fc); spin_unlock_irqrestore(&port->lock, flags); /* Don't rewrite B0 */ if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); } static const char *sprd_type(struct uart_port *port) { return "SPX"; } static void sprd_release_port(struct uart_port *port) { /* nothing to do */ } static int sprd_request_port(struct uart_port *port) { return 0; } static void sprd_config_port(struct uart_port *port, int flags) { if (flags & UART_CONFIG_TYPE) port->type = PORT_SPRD; } static int sprd_verify_port(struct uart_port *port, struct serial_struct *ser) { if (ser->type != PORT_SPRD) return -EINVAL; if (port->irq != ser->irq) return -EINVAL; if (port->iotype != ser->io_type) return -EINVAL; return 0; } static struct uart_ops serial_sprd_ops = { .tx_empty = sprd_tx_empty, .get_mctrl = sprd_get_mctrl, .set_mctrl = sprd_set_mctrl, .stop_tx = sprd_stop_tx, .start_tx = sprd_start_tx, .stop_rx = sprd_stop_rx, .break_ctl = sprd_break_ctl, .startup = sprd_startup, .shutdown = sprd_shutdown, .set_termios = sprd_set_termios, .type = sprd_type, .release_port = sprd_release_port, .request_port = sprd_request_port, .config_port = sprd_config_port, .verify_port = sprd_verify_port, }; #ifdef CONFIG_SERIAL_SPRD_CONSOLE static inline 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 = serial_in(port, SPRD_STS1); if (--tmout == 0) break; udelay(1); } while (status & 0xff00); } static void sprd_console_putchar(struct uart_port *port, int ch) { wait_for_xmitr(port); serial_out(port, SPRD_TXD, ch); } static void sprd_console_write(struct console *co, const char *s, unsigned int count) { struct uart_port *port = &sprd_port[co->index]->port; int locked = 1; unsigned long flags; if (port->sysrq) locked = 0; else if (oops_in_progress) locked = spin_trylock_irqsave(&port->lock, flags); else spin_lock_irqsave(&port->lock, flags); uart_console_write(port, s, count, sprd_console_putchar); /* wait for transmitter to become empty */ wait_for_xmitr(port); if (locked) spin_unlock_irqrestore(&port->lock, flags); } static int __init sprd_console_setup(struct console *co, char *options) { struct uart_port *port; int baud = 115200; int bits = 8; int parity = 'n'; int flow = 'n'; if (co->index >= UART_NR_MAX || co->index < 0) co->index = 0; port = &sprd_port[co->index]->port; if (port == NULL) { pr_info("serial port %d not yet initialized\n", co->index); return -ENODEV; } if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); return uart_set_options(port, co, baud, parity, bits, flow); } static struct uart_driver sprd_uart_driver; static struct console sprd_console = { .name = SPRD_TTY_NAME, .write = sprd_console_write, .device = uart_console_device, .setup = sprd_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &sprd_uart_driver, }; #define SPRD_CONSOLE (&sprd_console) /* Support for earlycon */ static void sprd_putc(struct uart_port *port, int c) { unsigned int timeout = SPRD_TIMEOUT; while (timeout-- && !(readl(port->membase + SPRD_LSR) & SPRD_LSR_TX_OVER)) cpu_relax(); writeb(c, port->membase + SPRD_TXD); } static void sprd_early_write(struct console *con, const char *s, unsigned n) { struct earlycon_device *dev = con->data; uart_console_write(&dev->port, s, n, sprd_putc); } static int __init sprd_early_console_setup( struct earlycon_device *device, const char *opt) { if (!device->port.membase) return -ENODEV; device->con->write = sprd_early_write; return 0; } EARLYCON_DECLARE(sprd_serial, sprd_early_console_setup); OF_EARLYCON_DECLARE(sprd_serial, "sprd,sc9836-uart", sprd_early_console_setup); #else /* !CONFIG_SERIAL_SPRD_CONSOLE */ #define SPRD_CONSOLE NULL #endif static struct uart_driver sprd_uart_driver = { .owner = THIS_MODULE, .driver_name = "sprd_serial", .dev_name = SPRD_TTY_NAME, .major = 0, .minor = 0, .nr = UART_NR_MAX, .cons = SPRD_CONSOLE, }; static int sprd_probe_dt_alias(int index, struct device *dev) { struct device_node *np; int ret = index; if (!IS_ENABLED(CONFIG_OF)) return ret; np = dev->of_node; if (!np) return ret; ret = of_alias_get_id(np, "serial"); if (IS_ERR_VALUE(ret)) ret = index; else if (ret >= ARRAY_SIZE(sprd_port) || sprd_port[ret] != NULL) { dev_warn(dev, "requested serial port %d not available.\n", ret); ret = index; } return ret; } static int sprd_remove(struct platform_device *dev) { struct sprd_uart_port *sup = platform_get_drvdata(dev); if (sup) { uart_remove_one_port(&sprd_uart_driver, &sup->port); sprd_port[sup->port.line] = NULL; sprd_ports_num--; } if (!sprd_ports_num) uart_unregister_driver(&sprd_uart_driver); return 0; } static int sprd_probe(struct platform_device *pdev) { struct resource *res; struct uart_port *up; struct clk *clk; int irq; int index; int ret; for (index = 0; index < ARRAY_SIZE(sprd_port); index++) if (sprd_port[index] == NULL) break; if (index == ARRAY_SIZE(sprd_port)) return -EBUSY; index = sprd_probe_dt_alias(index, &pdev->dev); sprd_port[index] = devm_kzalloc(&pdev->dev, sizeof(*sprd_port[index]), GFP_KERNEL); if (!sprd_port[index]) return -ENOMEM; up = &sprd_port[index]->port; up->dev = &pdev->dev; up->line = index; up->type = PORT_SPRD; up->iotype = UPIO_MEM; up->uartclk = SPRD_DEF_RATE; up->fifosize = SPRD_FIFO_SIZE; up->ops = &serial_sprd_ops; up->flags = UPF_BOOT_AUTOCONF; clk = devm_clk_get(&pdev->dev, NULL); if (!IS_ERR(clk)) up->uartclk = clk_get_rate(clk); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) { dev_err(&pdev->dev, "not provide mem resource\n"); return -ENODEV; } up->mapbase = res->start; up->membase = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(up->membase)) return PTR_ERR(up->membase); irq = platform_get_irq(pdev, 0); if (irq < 0) { dev_err(&pdev->dev, "not provide irq resource\n"); return -ENODEV; } up->irq = irq; if (!sprd_ports_num) { ret = uart_register_driver(&sprd_uart_driver); if (ret < 0) { pr_err("Failed to register SPRD-UART driver\n"); return ret; } } sprd_ports_num++; ret = uart_add_one_port(&sprd_uart_driver, up); if (ret) { sprd_port[index] = NULL; sprd_remove(pdev); } platform_set_drvdata(pdev, up); return ret; } #ifdef CONFIG_PM_SLEEP static int sprd_suspend(struct device *dev) { struct sprd_uart_port *sup = dev_get_drvdata(dev); uart_suspend_port(&sprd_uart_driver, &sup->port); return 0; } static int sprd_resume(struct device *dev) { struct sprd_uart_port *sup = dev_get_drvdata(dev); uart_resume_port(&sprd_uart_driver, &sup->port); return 0; } #endif static SIMPLE_DEV_PM_OPS(sprd_pm_ops, sprd_suspend, sprd_resume); static const struct of_device_id serial_ids[] = { {.compatible = "sprd,sc9836-uart",}, {} }; static struct platform_driver sprd_platform_driver = { .probe = sprd_probe, .remove = sprd_remove, .driver = { .name = "sprd_serial", .of_match_table = of_match_ptr(serial_ids), .pm = &sprd_pm_ops, }, }; module_platform_driver(sprd_platform_driver); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("Spreadtrum SoC serial driver series");