| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Vineet Gupta | 2394 | 97.71% | 12 | 57.14% |
| Geert Uytterhoeven | 27 | 1.10% | 1 | 4.76% |
| Viresh Kumar | 14 | 0.57% | 1 | 4.76% |
| Jiri Slaby | 6 | 0.24% | 2 | 9.52% |
| Peter Hurley | 4 | 0.16% | 1 | 4.76% |
| Greg Kroah-Hartman | 2 | 0.08% | 2 | 9.52% |
| Axel Lin | 2 | 0.08% | 1 | 4.76% |
| Julia Lawall | 1 | 0.04% | 1 | 4.76% |
| Total | 2450 | 21 |
// SPDX-License-Identifier: GPL-2.0 /* * ARC On-Chip(fpga) UART Driver * * Copyright (C) 2010-2012 Synopsys, Inc. (www.synopsys.com) * * vineetg: July 10th 2012 * -Decoupled the driver from arch/arc * +Using platform_get_resource() for irq/membase (thx to bfin_uart.c) * +Using early_platform_xxx() for early console (thx to mach-shmobile/xxx) * * Vineetg: Aug 21st 2010 * -Is uart_tx_stopped() not done in tty write path as it has already been * taken care of, in serial core * * Vineetg: Aug 18th 2010 * -New Serial Core based ARC UART driver * -Derived largely from blackfin driver albiet with some major tweaks * * TODO: * -check if sysreq works */ #if defined(CONFIG_SERIAL_ARC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) #define SUPPORT_SYSRQ #endif #include <linux/module.h> #include <linux/serial.h> #include <linux/console.h> #include <linux/sysrq.h> #include <linux/platform_device.h> #include <linux/tty.h> #include <linux/tty_flip.h> #include <linux/serial_core.h> #include <linux/io.h> #include <linux/of_irq.h> #include <linux/of_address.h> /************************************* * ARC UART Hardware Specs ************************************/ #define ARC_UART_TX_FIFO_SIZE 1 /* * UART Register set (this is not a Standards Compliant IP) * Also each reg is Word aligned, but only 8 bits wide */ #define R_ID0 0 #define R_ID1 4 #define R_ID2 8 #define R_ID3 12 #define R_DATA 16 #define R_STS 20 #define R_BAUDL 24 #define R_BAUDH 28 /* Bits for UART Status Reg (R/W) */ #define RXIENB 0x04 /* Receive Interrupt Enable */ #define TXIENB 0x40 /* Transmit Interrupt Enable */ #define RXEMPTY 0x20 /* Receive FIFO Empty: No char receivede */ #define TXEMPTY 0x80 /* Transmit FIFO Empty, thus char can be written into */ #define RXFULL 0x08 /* Receive FIFO full */ #define RXFULL1 0x10 /* Receive FIFO has space for 1 char (tot space=4) */ #define RXFERR 0x01 /* Frame Error: Stop Bit not detected */ #define RXOERR 0x02 /* OverFlow Err: Char recv but RXFULL still set */ /* Uart bit fiddling helpers: lowest level */ #define RBASE(port, reg) (port->membase + reg) #define UART_REG_SET(u, r, v) writeb((v), RBASE(u, r)) #define UART_REG_GET(u, r) readb(RBASE(u, r)) #define UART_REG_OR(u, r, v) UART_REG_SET(u, r, UART_REG_GET(u, r) | (v)) #define UART_REG_CLR(u, r, v) UART_REG_SET(u, r, UART_REG_GET(u, r) & ~(v)) /* Uart bit fiddling helpers: API level */ #define UART_SET_DATA(uart, val) UART_REG_SET(uart, R_DATA, val) #define UART_GET_DATA(uart) UART_REG_GET(uart, R_DATA) #define UART_SET_BAUDH(uart, val) UART_REG_SET(uart, R_BAUDH, val) #define UART_SET_BAUDL(uart, val) UART_REG_SET(uart, R_BAUDL, val) #define UART_CLR_STATUS(uart, val) UART_REG_CLR(uart, R_STS, val) #define UART_GET_STATUS(uart) UART_REG_GET(uart, R_STS) #define UART_ALL_IRQ_DISABLE(uart) UART_REG_CLR(uart, R_STS, RXIENB|TXIENB) #define UART_RX_IRQ_DISABLE(uart) UART_REG_CLR(uart, R_STS, RXIENB) #define UART_TX_IRQ_DISABLE(uart) UART_REG_CLR(uart, R_STS, TXIENB) #define UART_ALL_IRQ_ENABLE(uart) UART_REG_OR(uart, R_STS, RXIENB|TXIENB) #define UART_RX_IRQ_ENABLE(uart) UART_REG_OR(uart, R_STS, RXIENB) #define UART_TX_IRQ_ENABLE(uart) UART_REG_OR(uart, R_STS, TXIENB) #define ARC_SERIAL_DEV_NAME "ttyARC" struct arc_uart_port { struct uart_port port; unsigned long baud; }; #define to_arc_port(uport) container_of(uport, struct arc_uart_port, port) static struct arc_uart_port arc_uart_ports[CONFIG_SERIAL_ARC_NR_PORTS]; #ifdef CONFIG_SERIAL_ARC_CONSOLE static struct console arc_console; #endif #define DRIVER_NAME "arc-uart" static struct uart_driver arc_uart_driver = { .owner = THIS_MODULE, .driver_name = DRIVER_NAME, .dev_name = ARC_SERIAL_DEV_NAME, .major = 0, .minor = 0, .nr = CONFIG_SERIAL_ARC_NR_PORTS, #ifdef CONFIG_SERIAL_ARC_CONSOLE .cons = &arc_console, #endif }; static void arc_serial_stop_rx(struct uart_port *port) { UART_RX_IRQ_DISABLE(port); } static void arc_serial_stop_tx(struct uart_port *port) { while (!(UART_GET_STATUS(port) & TXEMPTY)) cpu_relax(); UART_TX_IRQ_DISABLE(port); } /* * Return TIOCSER_TEMT when transmitter is not busy. */ static unsigned int arc_serial_tx_empty(struct uart_port *port) { unsigned int stat; stat = UART_GET_STATUS(port); if (stat & TXEMPTY) return TIOCSER_TEMT; return 0; } /* * Driver internal routine, used by both tty(serial core) as well as tx-isr * -Called under spinlock in either cases * -also tty->stopped has already been checked * = by uart_start( ) before calling us * = tx_ist checks that too before calling */ static void arc_serial_tx_chars(struct uart_port *port) { struct circ_buf *xmit = &port->state->xmit; int sent = 0; unsigned char ch; if (unlikely(port->x_char)) { UART_SET_DATA(port, port->x_char); port->icount.tx++; port->x_char = 0; sent = 1; } else if (!uart_circ_empty(xmit)) { ch = xmit->buf[xmit->tail]; xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); port->icount.tx++; while (!(UART_GET_STATUS(port) & TXEMPTY)) cpu_relax(); UART_SET_DATA(port, ch); sent = 1; } /* * If num chars in xmit buffer are too few, ask tty layer for more. * By Hard ISR to schedule processing in software interrupt part */ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); if (sent) UART_TX_IRQ_ENABLE(port); } /* * port is locked and interrupts are disabled * uart_start( ) calls us under the port spinlock irqsave */ static void arc_serial_start_tx(struct uart_port *port) { arc_serial_tx_chars(port); } static void arc_serial_rx_chars(struct uart_port *port, unsigned int status) { unsigned int ch, flg = 0; /* * UART has 4 deep RX-FIFO. Driver's recongnition of this fact * is very subtle. Here's how ... * Upon getting a RX-Intr, such that RX-EMPTY=0, meaning data available, * driver reads the DATA Reg and keeps doing that in a loop, until * RX-EMPTY=1. Multiple chars being avail, with a single Interrupt, * before RX-EMPTY=0, implies some sort of buffering going on in the * controller, which is indeed the Rx-FIFO. */ do { /* * This could be an Rx Intr for err (no data), * so check err and clear that Intr first */ if (unlikely(status & (RXOERR | RXFERR))) { if (status & RXOERR) { port->icount.overrun++; flg = TTY_OVERRUN; UART_CLR_STATUS(port, RXOERR); } if (status & RXFERR) { port->icount.frame++; flg = TTY_FRAME; UART_CLR_STATUS(port, RXFERR); } } else flg = TTY_NORMAL; if (status & RXEMPTY) continue; ch = UART_GET_DATA(port); port->icount.rx++; if (!(uart_handle_sysrq_char(port, ch))) uart_insert_char(port, status, RXOERR, ch, flg); spin_unlock(&port->lock); tty_flip_buffer_push(&port->state->port); spin_lock(&port->lock); } while (!((status = UART_GET_STATUS(port)) & RXEMPTY)); } /* * A note on the Interrupt handling state machine of this driver * * kernel printk writes funnel thru the console driver framework and in order * to keep things simple as well as efficient, it writes to UART in polled * mode, in one shot, and exits. * * OTOH, Userland output (via tty layer), uses interrupt based writes as there * can be undeterministic delay between char writes. * * Thus Rx-interrupts are always enabled, while tx-interrupts are by default * disabled. * * When tty has some data to send out, serial core calls driver's start_tx * which * -checks-if-tty-buffer-has-char-to-send * -writes-data-to-uart * -enable-tx-intr * * Once data bits are pushed out, controller raises the Tx-room-avail-Interrupt. * The first thing Tx ISR does is disable further Tx interrupts (as this could * be the last char to send, before settling down into the quiet polled mode). * It then calls the exact routine used by tty layer write to send out any * more char in tty buffer. In case of sending, it re-enables Tx-intr. In case * of no data, it remains disabled. * This is how the transmit state machine is dynamically switched on/off */ static irqreturn_t arc_serial_isr(int irq, void *dev_id) { struct uart_port *port = dev_id; unsigned int status; status = UART_GET_STATUS(port); /* * Single IRQ for both Rx (data available) Tx (room available) Interrupt * notifications from the UART Controller. * To demultiplex between the two, we check the relevant bits */ if (status & RXIENB) { /* already in ISR, no need of xx_irqsave */ spin_lock(&port->lock); arc_serial_rx_chars(port, status); spin_unlock(&port->lock); } if ((status & TXIENB) && (status & TXEMPTY)) { /* Unconditionally disable further Tx-Interrupts. * will be enabled by tx_chars() if needed. */ UART_TX_IRQ_DISABLE(port); spin_lock(&port->lock); if (!uart_tx_stopped(port)) arc_serial_tx_chars(port); spin_unlock(&port->lock); } return IRQ_HANDLED; } static unsigned int arc_serial_get_mctrl(struct uart_port *port) { /* * Pretend we have a Modem status reg and following bits are * always set, to satify the serial core state machine * (DSR) Data Set Ready * (CTS) Clear To Send * (CAR) Carrier Detect */ return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR; } static void arc_serial_set_mctrl(struct uart_port *port, unsigned int mctrl) { /* MCR not present */ } static void arc_serial_break_ctl(struct uart_port *port, int break_state) { /* ARC UART doesn't support sending Break signal */ } static int arc_serial_startup(struct uart_port *port) { /* Before we hook up the ISR, Disable all UART Interrupts */ UART_ALL_IRQ_DISABLE(port); if (request_irq(port->irq, arc_serial_isr, 0, "arc uart rx-tx", port)) { dev_warn(port->dev, "Unable to attach ARC UART intr\n"); return -EBUSY; } UART_RX_IRQ_ENABLE(port); /* Only Rx IRQ enabled to begin with */ return 0; } /* This is not really needed */ static void arc_serial_shutdown(struct uart_port *port) { free_irq(port->irq, port); } static void arc_serial_set_termios(struct uart_port *port, struct ktermios *new, struct ktermios *old) { struct arc_uart_port *uart = to_arc_port(port); unsigned int baud, uartl, uarth, hw_val; unsigned long flags; /* * Use the generic handler so that any specially encoded baud rates * such as SPD_xx flags or "%B0" can be handled * Max Baud I suppose will not be more than current 115K * 4 * Formula for ARC UART is: hw-val = ((CLK/(BAUD*4)) -1) * spread over two 8-bit registers */ baud = uart_get_baud_rate(port, new, old, 0, 460800); hw_val = port->uartclk / (uart->baud * 4) - 1; uartl = hw_val & 0xFF; uarth = (hw_val >> 8) & 0xFF; spin_lock_irqsave(&port->lock, flags); UART_ALL_IRQ_DISABLE(port); UART_SET_BAUDL(port, uartl); UART_SET_BAUDH(port, uarth); UART_RX_IRQ_ENABLE(port); /* * UART doesn't support Parity/Hardware Flow Control; * Only supports 8N1 character size */ new->c_cflag &= ~(CMSPAR|CRTSCTS|CSIZE); new->c_cflag |= CS8; if (old) tty_termios_copy_hw(new, old); /* Don't rewrite B0 */ if (tty_termios_baud_rate(new)) tty_termios_encode_baud_rate(new, baud, baud); uart_update_timeout(port, new->c_cflag, baud); spin_unlock_irqrestore(&port->lock, flags); } static const char *arc_serial_type(struct uart_port *port) { return port->type == PORT_ARC ? DRIVER_NAME : NULL; } static void arc_serial_release_port(struct uart_port *port) { } static int arc_serial_request_port(struct uart_port *port) { return 0; } /* * Verify the new serial_struct (for TIOCSSERIAL). */ static int arc_serial_verify_port(struct uart_port *port, struct serial_struct *ser) { if (port->type != PORT_UNKNOWN && ser->type != PORT_ARC) return -EINVAL; return 0; } /* * Configure/autoconfigure the port. */ static void arc_serial_config_port(struct uart_port *port, int flags) { if (flags & UART_CONFIG_TYPE) port->type = PORT_ARC; } #ifdef CONFIG_CONSOLE_POLL static void arc_serial_poll_putchar(struct uart_port *port, unsigned char chr) { while (!(UART_GET_STATUS(port) & TXEMPTY)) cpu_relax(); UART_SET_DATA(port, chr); } static int arc_serial_poll_getchar(struct uart_port *port) { unsigned char chr; while (!(UART_GET_STATUS(port) & RXEMPTY)) cpu_relax(); chr = UART_GET_DATA(port); return chr; } #endif static const struct uart_ops arc_serial_pops = { .tx_empty = arc_serial_tx_empty, .set_mctrl = arc_serial_set_mctrl, .get_mctrl = arc_serial_get_mctrl, .stop_tx = arc_serial_stop_tx, .start_tx = arc_serial_start_tx, .stop_rx = arc_serial_stop_rx, .break_ctl = arc_serial_break_ctl, .startup = arc_serial_startup, .shutdown = arc_serial_shutdown, .set_termios = arc_serial_set_termios, .type = arc_serial_type, .release_port = arc_serial_release_port, .request_port = arc_serial_request_port, .config_port = arc_serial_config_port, .verify_port = arc_serial_verify_port, #ifdef CONFIG_CONSOLE_POLL .poll_put_char = arc_serial_poll_putchar, .poll_get_char = arc_serial_poll_getchar, #endif }; #ifdef CONFIG_SERIAL_ARC_CONSOLE static int arc_serial_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 < 0 || co->index >= CONFIG_SERIAL_ARC_NR_PORTS) return -ENODEV; /* * The uart port backing the console (e.g. ttyARC1) might not have been * init yet. If so, defer the console setup to after the port. */ port = &arc_uart_ports[co->index].port; if (!port->membase) return -ENODEV; if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); /* * Serial core will call port->ops->set_termios( ) * which will set the baud reg */ return uart_set_options(port, co, baud, parity, bits, flow); } static void arc_serial_console_putchar(struct uart_port *port, int ch) { while (!(UART_GET_STATUS(port) & TXEMPTY)) cpu_relax(); UART_SET_DATA(port, (unsigned char)ch); } /* * Interrupts are disabled on entering */ static void arc_serial_console_write(struct console *co, const char *s, unsigned int count) { struct uart_port *port = &arc_uart_ports[co->index].port; unsigned long flags; spin_lock_irqsave(&port->lock, flags); uart_console_write(port, s, count, arc_serial_console_putchar); spin_unlock_irqrestore(&port->lock, flags); } static struct console arc_console = { .name = ARC_SERIAL_DEV_NAME, .write = arc_serial_console_write, .device = uart_console_device, .setup = arc_serial_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &arc_uart_driver }; static void arc_early_serial_write(struct console *con, const char *s, unsigned int n) { struct earlycon_device *dev = con->data; uart_console_write(&dev->port, s, n, arc_serial_console_putchar); } static int __init arc_early_console_setup(struct earlycon_device *dev, const char *opt) { struct uart_port *port = &dev->port; unsigned int l, h, hw_val; if (!dev->port.membase) return -ENODEV; hw_val = port->uartclk / (dev->baud * 4) - 1; l = hw_val & 0xFF; h = (hw_val >> 8) & 0xFF; UART_SET_BAUDL(port, l); UART_SET_BAUDH(port, h); dev->con->write = arc_early_serial_write; return 0; } OF_EARLYCON_DECLARE(arc_uart, "snps,arc-uart", arc_early_console_setup); #endif /* CONFIG_SERIAL_ARC_CONSOLE */ static int arc_serial_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; struct arc_uart_port *uart; struct uart_port *port; int dev_id; u32 val; /* no device tree device */ if (!np) return -ENODEV; dev_id = of_alias_get_id(np, "serial"); if (dev_id < 0) dev_id = 0; if (dev_id >= ARRAY_SIZE(arc_uart_ports)) { dev_err(&pdev->dev, "serial%d out of range\n", dev_id); return -EINVAL; } uart = &arc_uart_ports[dev_id]; port = &uart->port; if (of_property_read_u32(np, "clock-frequency", &val)) { dev_err(&pdev->dev, "clock-frequency property NOTset\n"); return -EINVAL; } port->uartclk = val; if (of_property_read_u32(np, "current-speed", &val)) { dev_err(&pdev->dev, "current-speed property NOT set\n"); return -EINVAL; } uart->baud = val; port->membase = of_iomap(np, 0); if (!port->membase) /* No point of dev_err since UART itself is hosed here */ return -ENXIO; port->irq = irq_of_parse_and_map(np, 0); port->dev = &pdev->dev; port->iotype = UPIO_MEM; port->flags = UPF_BOOT_AUTOCONF; port->line = dev_id; port->ops = &arc_serial_pops; port->fifosize = ARC_UART_TX_FIFO_SIZE; /* * uart_insert_char( ) uses it in decideding whether to ignore a * char or not. Explicitly setting it here, removes the subtelty */ port->ignore_status_mask = 0; return uart_add_one_port(&arc_uart_driver, &arc_uart_ports[dev_id].port); } static int arc_serial_remove(struct platform_device *pdev) { /* This will never be called */ return 0; } static const struct of_device_id arc_uart_dt_ids[] = { { .compatible = "snps,arc-uart" }, { /* Sentinel */ } }; MODULE_DEVICE_TABLE(of, arc_uart_dt_ids); static struct platform_driver arc_platform_driver = { .probe = arc_serial_probe, .remove = arc_serial_remove, .driver = { .name = DRIVER_NAME, .of_match_table = arc_uart_dt_ids, }, }; static int __init arc_serial_init(void) { int ret; ret = uart_register_driver(&arc_uart_driver); if (ret) return ret; ret = platform_driver_register(&arc_platform_driver); if (ret) uart_unregister_driver(&arc_uart_driver); return ret; } static void __exit arc_serial_exit(void) { platform_driver_unregister(&arc_platform_driver); uart_unregister_driver(&arc_uart_driver); } module_init(arc_serial_init); module_exit(arc_serial_exit); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:" DRIVER_NAME); MODULE_AUTHOR("Vineet Gupta"); MODULE_DESCRIPTION("ARC(Synopsys) On-Chip(fpga) serial driver");
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