From c4415084218c68c5ee2fc583431e89a78d896b19 Mon Sep 17 00:00:00 2001 From: Dmitry Fink Date: Mon, 8 Jul 2013 13:04:44 +0300 Subject: OMAP: UART: Keep the TX fifo full when possible Current logic results in interrupt storm since the fifo is constantly below the threshold level. Change the logic to fill all the available spaces in the fifo as long as we have data to minimize the possibilty of underflow and elimiate excessive interrupts. Signed-off-by: Dmitry Fink Signed-off-by: Alexander Savchenko Signed-off-by: Greg Kroah-Hartman --- include/uapi/linux/serial_reg.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi') diff --git a/include/uapi/linux/serial_reg.h b/include/uapi/linux/serial_reg.h index e6322605b138..97c26beae605 100644 --- a/include/uapi/linux/serial_reg.h +++ b/include/uapi/linux/serial_reg.h @@ -366,6 +366,7 @@ #define UART_OMAP_MDR1_FIR_MODE 0x05 /* FIR mode */ #define UART_OMAP_MDR1_CIR_MODE 0x06 /* CIR mode */ #define UART_OMAP_MDR1_DISABLE 0x07 /* Disable (default state) */ +#define UART_OMAP_TXFIFO_LVL 0x1A /* TX FIFO fullness */ /* * These are definitions for the Exar XR17V35X and XR17(C|D)15X -- cgit v1.2.3 From c4b058560762ec7ffe159b668fc47a8b7e271949 Mon Sep 17 00:00:00 2001 From: Srinivas Kandagatla Date: Mon, 15 Jul 2013 12:39:23 +0100 Subject: serial:st-asc: Add ST ASC driver. This patch adds support to ASC (asynchronous serial controller) driver, which is basically a standard serial driver. This IP is common across all the ST parts for settop box platforms. ASC is embedded in ST COMMS IP block. It supports Rx & Tx functionality. It support all industry standard baud rates. Signed-off-by: Srinivas Kandagatla CC: Stephen Gallimore CC: Stuart Menefy CC: Arnd Bergmann CC: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- .../devicetree/bindings/tty/serial/st-asc.txt | 18 + drivers/tty/serial/Kconfig | 16 + drivers/tty/serial/Makefile | 1 + drivers/tty/serial/st-asc.c | 937 +++++++++++++++++++++ include/uapi/linux/serial_core.h | 3 + 5 files changed, 975 insertions(+) create mode 100644 Documentation/devicetree/bindings/tty/serial/st-asc.txt create mode 100644 drivers/tty/serial/st-asc.c (limited to 'include/uapi') diff --git a/Documentation/devicetree/bindings/tty/serial/st-asc.txt b/Documentation/devicetree/bindings/tty/serial/st-asc.txt new file mode 100644 index 000000000000..75d877f5968f --- /dev/null +++ b/Documentation/devicetree/bindings/tty/serial/st-asc.txt @@ -0,0 +1,18 @@ +*st-asc(Serial Port) + +Required properties: +- compatible : Should be "st,asc". +- reg, reg-names, interrupts, interrupt-names : Standard way to define device + resources with names. look in + Documentation/devicetree/bindings/resource-names.txt + +Optional properties: +- st,hw-flow-ctrl bool flag to enable hardware flow control. +- st,force-m1 bool flat to force asc to be in Mode-1 recommeded + for high bit rates (above 19.2K) +Example: +serial@fe440000{ + compatible = "st,asc"; + reg = <0xfe440000 0x2c>; + interrupts = <0 209 0>; +}; diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index 6e73781bea63..bdf5c0e44b68 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -1497,6 +1497,22 @@ config SERIAL_FSL_LPUART_CONSOLE If you have enabled the lpuart serial port on the Freescale SoCs, you can make it the console by answering Y to this option. +config SERIAL_ST_ASC + tristate "ST ASC serial port support" + select SERIAL_CORE + help + This driver is for the on-chip Asychronous Serial Controller on + STMicroelectronics STi SoCs. + ASC is embedded in ST COMMS IP block. It supports Rx & Tx functionality. + It support all industry standard baud rates. + + If unsure, say N. + +config SERIAL_ST_ASC_CONSOLE + bool "Support for console on ST ASC" + depends on SERIAL_ST_ASC=y + select SERIAL_CORE_CONSOLE + endmenu endif # TTY diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile index cf650f0cd6e4..47b679c547e9 100644 --- a/drivers/tty/serial/Makefile +++ b/drivers/tty/serial/Makefile @@ -65,6 +65,7 @@ obj-$(CONFIG_SERIAL_KGDB_NMI) += kgdb_nmi.o obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o obj-$(CONFIG_SERIAL_OMAP) += omap-serial.o obj-$(CONFIG_SERIAL_ALTERA_UART) += altera_uart.o +obj-$(CONFIG_SERIAL_ST_ASC) += st-asc.o obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o obj-$(CONFIG_SERIAL_QE) += ucc_uart.o obj-$(CONFIG_SERIAL_TIMBERDALE) += timbuart.o diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c new file mode 100644 index 000000000000..183879825695 --- /dev/null +++ b/drivers/tty/serial/st-asc.c @@ -0,0 +1,937 @@ +/* + * st-asc.c: ST Asynchronous serial controller (ASC) driver + * + * Copyright (C) 2003-2013 STMicroelectronics (R&D) Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ + +#if defined(CONFIG_SERIAL_ST_ASC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) +#define SUPPORT_SYSRQ +#endif + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define DRIVER_NAME "st-asc" +#define ASC_SERIAL_NAME "ttyAS" +#define ASC_FIFO_SIZE 16 +#define ASC_MAX_PORTS 8 + +struct asc_port { + struct uart_port port; + struct clk *clk; + unsigned int hw_flow_control:1; + unsigned int force_m1:1; +}; + +static struct asc_port asc_ports[ASC_MAX_PORTS]; +static struct uart_driver asc_uart_driver; + +/*---- UART Register definitions ------------------------------*/ + +/* Register offsets */ + +#define ASC_BAUDRATE 0x00 +#define ASC_TXBUF 0x04 +#define ASC_RXBUF 0x08 +#define ASC_CTL 0x0C +#define ASC_INTEN 0x10 +#define ASC_STA 0x14 +#define ASC_GUARDTIME 0x18 +#define ASC_TIMEOUT 0x1C +#define ASC_TXRESET 0x20 +#define ASC_RXRESET 0x24 +#define ASC_RETRIES 0x28 + +/* ASC_RXBUF */ +#define ASC_RXBUF_PE 0x100 +#define ASC_RXBUF_FE 0x200 +/** + * Some of status comes from higher bits of the character and some come from + * the status register. Combining both of them in to single status using dummy + * bits. + */ +#define ASC_RXBUF_DUMMY_RX 0x10000 +#define ASC_RXBUF_DUMMY_BE 0x20000 +#define ASC_RXBUF_DUMMY_OE 0x40000 + +/* ASC_CTL */ + +#define ASC_CTL_MODE_MSK 0x0007 +#define ASC_CTL_MODE_8BIT 0x0001 +#define ASC_CTL_MODE_7BIT_PAR 0x0003 +#define ASC_CTL_MODE_9BIT 0x0004 +#define ASC_CTL_MODE_8BIT_WKUP 0x0005 +#define ASC_CTL_MODE_8BIT_PAR 0x0007 +#define ASC_CTL_STOP_MSK 0x0018 +#define ASC_CTL_STOP_HALFBIT 0x0000 +#define ASC_CTL_STOP_1BIT 0x0008 +#define ASC_CTL_STOP_1_HALFBIT 0x0010 +#define ASC_CTL_STOP_2BIT 0x0018 +#define ASC_CTL_PARITYODD 0x0020 +#define ASC_CTL_LOOPBACK 0x0040 +#define ASC_CTL_RUN 0x0080 +#define ASC_CTL_RXENABLE 0x0100 +#define ASC_CTL_SCENABLE 0x0200 +#define ASC_CTL_FIFOENABLE 0x0400 +#define ASC_CTL_CTSENABLE 0x0800 +#define ASC_CTL_BAUDMODE 0x1000 + +/* ASC_GUARDTIME */ + +#define ASC_GUARDTIME_MSK 0x00FF + +/* ASC_INTEN */ + +#define ASC_INTEN_RBE 0x0001 +#define ASC_INTEN_TE 0x0002 +#define ASC_INTEN_THE 0x0004 +#define ASC_INTEN_PE 0x0008 +#define ASC_INTEN_FE 0x0010 +#define ASC_INTEN_OE 0x0020 +#define ASC_INTEN_TNE 0x0040 +#define ASC_INTEN_TOI 0x0080 +#define ASC_INTEN_RHF 0x0100 + +/* ASC_RETRIES */ + +#define ASC_RETRIES_MSK 0x00FF + +/* ASC_RXBUF */ + +#define ASC_RXBUF_MSK 0x03FF + +/* ASC_STA */ + +#define ASC_STA_RBF 0x0001 +#define ASC_STA_TE 0x0002 +#define ASC_STA_THE 0x0004 +#define ASC_STA_PE 0x0008 +#define ASC_STA_FE 0x0010 +#define ASC_STA_OE 0x0020 +#define ASC_STA_TNE 0x0040 +#define ASC_STA_TOI 0x0080 +#define ASC_STA_RHF 0x0100 +#define ASC_STA_TF 0x0200 +#define ASC_STA_NKD 0x0400 + +/* ASC_TIMEOUT */ + +#define ASC_TIMEOUT_MSK 0x00FF + +/* ASC_TXBUF */ + +#define ASC_TXBUF_MSK 0x01FF + +/*---- Inline function definitions ---------------------------*/ + +static inline struct asc_port *to_asc_port(struct uart_port *port) +{ + return container_of(port, struct asc_port, port); +} + +static inline u32 asc_in(struct uart_port *port, u32 offset) +{ + return readl(port->membase + offset); +} + +static inline void asc_out(struct uart_port *port, u32 offset, u32 value) +{ + writel(value, port->membase + offset); +} + +/* + * Some simple utility functions to enable and disable interrupts. + * Note that these need to be called with interrupts disabled. + */ +static inline void asc_disable_tx_interrupts(struct uart_port *port) +{ + u32 intenable = asc_in(port, ASC_INTEN) & ~ASC_INTEN_THE; + asc_out(port, ASC_INTEN, intenable); + (void)asc_in(port, ASC_INTEN); /* Defeat bus write posting */ +} + +static inline void asc_enable_tx_interrupts(struct uart_port *port) +{ + u32 intenable = asc_in(port, ASC_INTEN) | ASC_INTEN_THE; + asc_out(port, ASC_INTEN, intenable); +} + +static inline void asc_disable_rx_interrupts(struct uart_port *port) +{ + u32 intenable = asc_in(port, ASC_INTEN) & ~ASC_INTEN_RBE; + asc_out(port, ASC_INTEN, intenable); + (void)asc_in(port, ASC_INTEN); /* Defeat bus write posting */ +} + +static inline void asc_enable_rx_interrupts(struct uart_port *port) +{ + u32 intenable = asc_in(port, ASC_INTEN) | ASC_INTEN_RBE; + asc_out(port, ASC_INTEN, intenable); +} + +static inline u32 asc_txfifo_is_empty(struct uart_port *port) +{ + return asc_in(port, ASC_STA) & ASC_STA_TE; +} + +static inline int asc_txfifo_is_full(struct uart_port *port) +{ + return asc_in(port, ASC_STA) & ASC_STA_TF; +} + +static inline const char *asc_port_name(struct uart_port *port) +{ + return to_platform_device(port->dev)->name; +} + +/*----------------------------------------------------------------------*/ + +/* + * This section contains code to support the use of the ASC as a + * generic serial port. + */ + +static inline unsigned asc_hw_txroom(struct uart_port *port) +{ + u32 status = asc_in(port, ASC_STA); + + if (status & ASC_STA_THE) + return port->fifosize / 2; + else if (!(status & ASC_STA_TF)) + return 1; + + return 0; +} + +/* + * Start transmitting chars. + * This is called from both interrupt and task level. + * Either way interrupts are disabled. + */ +static void asc_transmit_chars(struct uart_port *port) +{ + struct circ_buf *xmit = &port->state->xmit; + int txroom; + unsigned char c; + + txroom = asc_hw_txroom(port); + + if ((txroom != 0) && port->x_char) { + c = port->x_char; + port->x_char = 0; + asc_out(port, ASC_TXBUF, c); + port->icount.tx++; + txroom = asc_hw_txroom(port); + } + + if (uart_tx_stopped(port)) { + /* + * We should try and stop the hardware here, but I + * don't think the ASC has any way to do that. + */ + asc_disable_tx_interrupts(port); + return; + } + + if (uart_circ_empty(xmit)) { + asc_disable_tx_interrupts(port); + return; + } + + if (txroom == 0) + return; + + do { + c = xmit->buf[xmit->tail]; + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + asc_out(port, ASC_TXBUF, c); + port->icount.tx++; + txroom--; + } while ((txroom > 0) && (!uart_circ_empty(xmit))); + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(port); + + if (uart_circ_empty(xmit)) + asc_disable_tx_interrupts(port); +} + +static void asc_receive_chars(struct uart_port *port) +{ + struct tty_port *tport = &port->state->port; + unsigned long status; + unsigned long c = 0; + char flag; + + if (port->irq_wake) + pm_wakeup_event(tport->tty->dev, 0); + + while ((status = asc_in(port, ASC_STA)) & ASC_STA_RBF) { + c = asc_in(port, ASC_RXBUF) | ASC_RXBUF_DUMMY_RX; + flag = TTY_NORMAL; + port->icount.rx++; + + if ((c & (ASC_RXBUF_FE | ASC_RXBUF_PE)) || + status & ASC_STA_OE) { + + if (c & ASC_RXBUF_FE) { + if (c == ASC_RXBUF_FE) { + port->icount.brk++; + if (uart_handle_break(port)) + continue; + c |= ASC_RXBUF_DUMMY_BE; + } else { + port->icount.frame++; + } + } else if (c & ASC_RXBUF_PE) { + port->icount.parity++; + } + /* + * Reading any data from the RX FIFO clears the + * overflow error condition. + */ + if (status & ASC_STA_OE) { + port->icount.overrun++; + c |= ASC_RXBUF_DUMMY_OE; + } + + c &= port->read_status_mask; + + if (c & ASC_RXBUF_DUMMY_BE) + flag = TTY_BREAK; + else if (c & ASC_RXBUF_PE) + flag = TTY_PARITY; + else if (c & ASC_RXBUF_FE) + flag = TTY_FRAME; + } + + if (uart_handle_sysrq_char(port, c)) + continue; + + uart_insert_char(port, c, ASC_RXBUF_DUMMY_OE, c & 0xff, flag); + } + + /* Tell the rest of the system the news. New characters! */ + tty_flip_buffer_push(tport); +} + +static irqreturn_t asc_interrupt(int irq, void *ptr) +{ + struct uart_port *port = ptr; + u32 status; + + spin_lock(&port->lock); + + status = asc_in(port, ASC_STA); + + if (status & ASC_STA_RBF) { + /* Receive FIFO not empty */ + asc_receive_chars(port); + } + + if ((status & ASC_STA_THE) && + (asc_in(port, ASC_INTEN) & ASC_INTEN_THE)) { + /* Transmitter FIFO at least half empty */ + asc_transmit_chars(port); + } + + spin_unlock(&port->lock); + + return IRQ_HANDLED; +} + +/*----------------------------------------------------------------------*/ + +/* + * UART Functions + */ + +static unsigned int asc_tx_empty(struct uart_port *port) +{ + return asc_txfifo_is_empty(port) ? TIOCSER_TEMT : 0; +} + +static void asc_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + /* + * This routine is used for seting signals of: DTR, DCD, CTS/RTS + * We use ASC's hardware for CTS/RTS, so don't need any for that. + * Some boards have DTR and DCD implemented using PIO pins, + * code to do this should be hooked in here. + */ +} + +static unsigned int asc_get_mctrl(struct uart_port *port) +{ + /* + * This routine is used for geting signals of: DTR, DCD, DSR, RI, + * and CTS/RTS + */ + return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; +} + +/* There are probably characters waiting to be transmitted. */ +static void asc_start_tx(struct uart_port *port) +{ + struct circ_buf *xmit = &port->state->xmit; + + if (!uart_circ_empty(xmit)) + asc_enable_tx_interrupts(port); +} + +/* Transmit stop */ +static void asc_stop_tx(struct uart_port *port) +{ + asc_disable_tx_interrupts(port); +} + +/* Receive stop */ +static void asc_stop_rx(struct uart_port *port) +{ + asc_disable_rx_interrupts(port); +} + +/* Force modem status interrupts on */ +static void asc_enable_ms(struct uart_port *port) +{ + /* Nothing here yet .. */ +} + +/* Handle breaks - ignored by us */ +static void asc_break_ctl(struct uart_port *port, int break_state) +{ + /* Nothing here yet .. */ +} + +/* + * Enable port for reception. + */ +static int asc_startup(struct uart_port *port) +{ + if (request_irq(port->irq, asc_interrupt, IRQF_NO_SUSPEND, + asc_port_name(port), port)) { + dev_err(port->dev, "cannot allocate irq.\n"); + return -ENODEV; + } + + asc_transmit_chars(port); + asc_enable_rx_interrupts(port); + + return 0; +} + +static void asc_shutdown(struct uart_port *port) +{ + asc_disable_tx_interrupts(port); + asc_disable_rx_interrupts(port); + free_irq(port->irq, port); +} + +static void asc_pm(struct uart_port *port, unsigned int state, + unsigned int oldstate) +{ + struct asc_port *ascport = to_asc_port(port); + unsigned long flags = 0; + u32 ctl; + + switch (state) { + case UART_PM_STATE_ON: + clk_prepare_enable(ascport->clk); + break; + case UART_PM_STATE_OFF: + /* + * Disable the ASC baud rate generator, which is as close as + * we can come to turning it off. Note this is not called with + * the port spinlock held. + */ + spin_lock_irqsave(&port->lock, flags); + ctl = asc_in(port, ASC_CTL) & ~ASC_CTL_RUN; + asc_out(port, ASC_CTL, ctl); + spin_unlock_irqrestore(&port->lock, flags); + clk_disable_unprepare(ascport->clk); + break; + } +} + +static void asc_set_termios(struct uart_port *port, struct ktermios *termios, + struct ktermios *old) +{ + struct asc_port *ascport = to_asc_port(port); + unsigned int baud; + u32 ctrl_val; + tcflag_t cflag; + unsigned long flags; + + /* Update termios to reflect hardware capabilities */ + termios->c_cflag &= ~(CMSPAR | + (ascport->hw_flow_control ? 0 : CRTSCTS)); + + port->uartclk = clk_get_rate(ascport->clk); + + baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16); + cflag = termios->c_cflag; + + spin_lock_irqsave(&port->lock, flags); + + /* read control register */ + ctrl_val = asc_in(port, ASC_CTL); + + /* stop serial port and reset value */ + asc_out(port, ASC_CTL, (ctrl_val & ~ASC_CTL_RUN)); + ctrl_val = ASC_CTL_RXENABLE | ASC_CTL_FIFOENABLE; + + /* reset fifo rx & tx */ + asc_out(port, ASC_TXRESET, 1); + asc_out(port, ASC_RXRESET, 1); + + /* set character length */ + if ((cflag & CSIZE) == CS7) { + ctrl_val |= ASC_CTL_MODE_7BIT_PAR; + } else { + ctrl_val |= (cflag & PARENB) ? ASC_CTL_MODE_8BIT_PAR : + ASC_CTL_MODE_8BIT; + } + + /* set stop bit */ + ctrl_val |= (cflag & CSTOPB) ? ASC_CTL_STOP_2BIT : ASC_CTL_STOP_1BIT; + + /* odd parity */ + if (cflag & PARODD) + ctrl_val |= ASC_CTL_PARITYODD; + + /* hardware flow control */ + if ((cflag & CRTSCTS)) + ctrl_val |= ASC_CTL_CTSENABLE; + + if ((baud < 19200) && !ascport->force_m1) { + asc_out(port, ASC_BAUDRATE, (port->uartclk / (16 * baud))); + } else { + /* + * MODE 1: recommended for high bit rates (above 19.2K) + * + * baudrate * 16 * 2^16 + * ASCBaudRate = ------------------------ + * inputclock + * + * However to keep the maths inside 32bits we divide top and + * bottom by 64. The +1 is to avoid a divide by zero if the + * input clock rate is something unexpected. + */ + u32 counter = (baud * 16384) / ((port->uartclk / 64) + 1); + asc_out(port, ASC_BAUDRATE, counter); + ctrl_val |= ASC_CTL_BAUDMODE; + } + + uart_update_timeout(port, cflag, baud); + + ascport->port.read_status_mask = ASC_RXBUF_DUMMY_OE; + if (termios->c_iflag & INPCK) + ascport->port.read_status_mask |= ASC_RXBUF_FE | ASC_RXBUF_PE; + if (termios->c_iflag & (BRKINT | PARMRK)) + ascport->port.read_status_mask |= ASC_RXBUF_DUMMY_BE; + + /* + * Characters to ignore + */ + ascport->port.ignore_status_mask = 0; + if (termios->c_iflag & IGNPAR) + ascport->port.ignore_status_mask |= ASC_RXBUF_FE | ASC_RXBUF_PE; + if (termios->c_iflag & IGNBRK) { + ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_BE; + /* + * If we're ignoring parity and break indicators, + * ignore overruns too (for real raw support). + */ + if (termios->c_iflag & IGNPAR) + ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_OE; + } + + /* + * Ignore all characters if CREAD is not set. + */ + if (!(termios->c_cflag & CREAD)) + ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_RX; + + /* Set the timeout */ + asc_out(port, ASC_TIMEOUT, 20); + + /* write final value and enable port */ + asc_out(port, ASC_CTL, (ctrl_val | ASC_CTL_RUN)); + + spin_unlock_irqrestore(&port->lock, flags); +} + +static const char *asc_type(struct uart_port *port) +{ + return (port->type == PORT_ASC) ? DRIVER_NAME : NULL; +} + +static void asc_release_port(struct uart_port *port) +{ +} + +static int asc_request_port(struct uart_port *port) +{ + return 0; +} + +/* + * Called when the port is opened, and UPF_BOOT_AUTOCONF flag is set + * Set type field if successful + */ +static void asc_config_port(struct uart_port *port, int flags) +{ + if ((flags & UART_CONFIG_TYPE)) + port->type = PORT_ASC; +} + +static int +asc_verify_port(struct uart_port *port, struct serial_struct *ser) +{ + /* No user changeable parameters */ + return -EINVAL; +} + +#ifdef CONFIG_CONSOLE_POLL +/* + * Console polling routines for writing and reading from the uart while + * in an interrupt or debug context (i.e. kgdb). + */ + +static int asc_get_poll_char(struct uart_port *port) +{ + if (!(asc_in(port, ASC_STA) & ASC_STA_RBF)) + return NO_POLL_CHAR; + + return asc_in(port, ASC_RXBUF); +} + +static void asc_put_poll_char(struct uart_port *port, unsigned char c) +{ + while (asc_txfifo_is_full(port)) + cpu_relax(); + asc_out(port, ASC_TXBUF, c); +} + +#endif /* CONFIG_CONSOLE_POLL */ + +/*---------------------------------------------------------------------*/ + +static struct uart_ops asc_uart_ops = { + .tx_empty = asc_tx_empty, + .set_mctrl = asc_set_mctrl, + .get_mctrl = asc_get_mctrl, + .start_tx = asc_start_tx, + .stop_tx = asc_stop_tx, + .stop_rx = asc_stop_rx, + .enable_ms = asc_enable_ms, + .break_ctl = asc_break_ctl, + .startup = asc_startup, + .shutdown = asc_shutdown, + .set_termios = asc_set_termios, + .type = asc_type, + .release_port = asc_release_port, + .request_port = asc_request_port, + .config_port = asc_config_port, + .verify_port = asc_verify_port, + .pm = asc_pm, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = asc_get_poll_char, + .poll_put_char = asc_put_poll_char, +#endif /* CONFIG_CONSOLE_POLL */ +}; + +static int asc_init_port(struct asc_port *ascport, + struct platform_device *pdev) +{ + struct uart_port *port = &ascport->port; + struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + if (!res) { + dev_err(&pdev->dev, "Unable to get io resource\n"); + return -ENODEV; + } + + port->iotype = UPIO_MEM; + port->flags = UPF_BOOT_AUTOCONF; + port->ops = &asc_uart_ops; + port->fifosize = ASC_FIFO_SIZE; + port->dev = &pdev->dev; + port->mapbase = res->start; + port->irq = platform_get_irq(pdev, 0); + + port->membase = devm_request_and_ioremap(&pdev->dev, res); + if (!port->membase) { + dev_err(&pdev->dev, "Unable to request io memory\n"); + return -ENODEV; + } + + spin_lock_init(&port->lock); + + ascport->clk = devm_clk_get(&pdev->dev, NULL); + + if (WARN_ON(IS_ERR(ascport->clk))) + return -EINVAL; + /* ensure that clk rate is correct by enabling the clk */ + clk_prepare_enable(ascport->clk); + ascport->port.uartclk = clk_get_rate(ascport->clk); + WARN_ON(ascport->port.uartclk == 0); + clk_disable_unprepare(ascport->clk); + + return 0; +} + +static struct asc_port *asc_of_get_asc_port(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + int id; + + if (!np) + return NULL; + + id = of_alias_get_id(np, ASC_SERIAL_NAME); + + if (id < 0) + id = 0; + + if (WARN_ON(id >= ASC_MAX_PORTS)) + return NULL; + + asc_ports[id].hw_flow_control = of_property_read_bool(np, + "st,hw-flow-control"); + asc_ports[id].force_m1 = of_property_read_bool(np, "st,force_m1"); + asc_ports[id].port.line = id; + return &asc_ports[id]; +} + +static struct of_device_id asc_match[] = { + { .compatible = "st,asc", }, + {}, +}; + +MODULE_DEVICE_TABLE(of, asc_match); + +static int asc_serial_probe(struct platform_device *pdev) +{ + int ret; + struct asc_port *ascport; + + ascport = asc_of_get_asc_port(pdev); + if (!ascport) + return -ENODEV; + + ret = asc_init_port(ascport, pdev); + if (ret) + return ret; + + ret = uart_add_one_port(&asc_uart_driver, &ascport->port); + if (ret) + return ret; + + platform_set_drvdata(pdev, &ascport->port); + + return 0; +} + +static int asc_serial_remove(struct platform_device *pdev) +{ + struct uart_port *port = platform_get_drvdata(pdev); + + platform_set_drvdata(pdev, NULL); + return uart_remove_one_port(&asc_uart_driver, port); +} + +#ifdef CONFIG_PM_SLEEP +static int asc_serial_suspend(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct uart_port *port = platform_get_drvdata(pdev); + + return uart_suspend_port(&asc_uart_driver, port); +} + +static int asc_serial_resume(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct uart_port *port = platform_get_drvdata(pdev); + + return uart_resume_port(&asc_uart_driver, port); +} + +#endif /* CONFIG_PM_SLEEP */ + +/*----------------------------------------------------------------------*/ + +#ifdef CONFIG_SERIAL_ST_ASC_CONSOLE +static void asc_console_putchar(struct uart_port *port, int ch) +{ + unsigned int timeout = 1000000; + + /* Wait for upto 1 second in case flow control is stopping us. */ + while (--timeout && asc_txfifo_is_full(port)) + udelay(1); + + asc_out(port, ASC_TXBUF, ch); +} + +/* + * Print a string to the serial port trying not to disturb + * any possible real use of the port... + */ + +static void asc_console_write(struct console *co, const char *s, unsigned count) +{ + struct uart_port *port = &asc_ports[co->index].port; + unsigned long flags; + unsigned long timeout = 1000000; + int locked = 1; + u32 intenable; + + local_irq_save(flags); + if (port->sysrq) + locked = 0; /* asc_interrupt has already claimed the lock */ + else if (oops_in_progress) + locked = spin_trylock(&port->lock); + else + spin_lock(&port->lock); + + /* + * Disable interrupts so we don't get the IRQ line bouncing + * up and down while interrupts are disabled. + */ + intenable = asc_in(port, ASC_INTEN); + asc_out(port, ASC_INTEN, 0); + (void)asc_in(port, ASC_INTEN); /* Defeat bus write posting */ + + uart_console_write(port, s, count, asc_console_putchar); + + while (--timeout && !asc_txfifo_is_empty(port)) + udelay(1); + + asc_out(port, ASC_INTEN, intenable); + + if (locked) + spin_unlock(&port->lock); + local_irq_restore(flags); +} + +static int asc_console_setup(struct console *co, char *options) +{ + struct asc_port *ascport; + int baud = 9600; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + + if (co->index >= ASC_MAX_PORTS) + return -ENODEV; + + ascport = &asc_ports[co->index]; + + /* + * This driver does not support early console initialization + * (use ARM early printk support instead), so we only expect + * this to be called during the uart port registration when the + * driver gets probed and the port should be mapped at that point. + */ + BUG_ON(ascport->port.mapbase == 0 || ascport->port.membase == NULL); + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + + return uart_set_options(&ascport->port, co, baud, parity, bits, flow); +} + +static struct console asc_console = { + .name = ASC_SERIAL_NAME, + .device = uart_console_device, + .write = asc_console_write, + .setup = asc_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &asc_uart_driver, +}; + +#define ASC_SERIAL_CONSOLE (&asc_console) + +#else +#define ASC_SERIAL_CONSOLE NULL +#endif /* CONFIG_SERIAL_ST_ASC_CONSOLE */ + +static struct uart_driver asc_uart_driver = { + .owner = THIS_MODULE, + .driver_name = DRIVER_NAME, + .dev_name = ASC_SERIAL_NAME, + .major = 0, + .minor = 0, + .nr = ASC_MAX_PORTS, + .cons = ASC_SERIAL_CONSOLE, +}; + +static const struct dev_pm_ops asc_serial_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(asc_serial_suspend, asc_serial_resume) +}; + +static struct platform_driver asc_serial_driver = { + .probe = asc_serial_probe, + .remove = asc_serial_remove, + .driver = { + .name = DRIVER_NAME, + .pm = &asc_serial_pm_ops, + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(asc_match), + }, +}; + +static int __init asc_init(void) +{ + int ret; + static char banner[] __initdata = + KERN_INFO "STMicroelectronics ASC driver initialized\n"; + + printk(banner); + + ret = uart_register_driver(&asc_uart_driver); + if (ret) + return ret; + + ret = platform_driver_register(&asc_serial_driver); + if (ret) + uart_unregister_driver(&asc_uart_driver); + + return ret; +} + +static void __exit asc_exit(void) +{ + platform_driver_unregister(&asc_serial_driver); + uart_unregister_driver(&asc_uart_driver); +} + +module_init(asc_init); +module_exit(asc_exit); + +MODULE_ALIAS("platform:" DRIVER_NAME); +MODULE_AUTHOR("STMicroelectronics (R&D) Limited"); +MODULE_DESCRIPTION("STMicroelectronics ASC serial port driver"); +MODULE_LICENSE("GPL"); diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h index 9119cc0977bf..e40ebe124ced 100644 --- a/include/uapi/linux/serial_core.h +++ b/include/uapi/linux/serial_core.h @@ -232,4 +232,7 @@ /* SH-SCI */ #define PORT_HSCIF 104 +/* ST ASC type numbers */ +#define PORT_ASC 105 + #endif /* _UAPILINUX_SERIAL_CORE_H */ -- cgit v1.2.3 From 355fe568e285815e6f62fcd004ca80085ae46a69 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Tue, 27 Aug 2013 16:02:18 -0700 Subject: Revert "OMAP: UART: Keep the TX fifo full when possible" This reverts commit c4415084218c68c5ee2fc583431e89a78d896b19. Kevin writes: Hmm, another OMAP serial patch that wasn't Cc'd to linux-omap where OMAP users might have seen it. :( I just bisected a strange problem in linux-next on OMAP3 down to this patch. Reverting it fixes the problem. On OMAP3530 Beagle and Overo, after boot, doing a 'cat /proc/cpuinfo' was not returning to a prompt, suggesting something strange with the FIFO. Hitting return gets me back to a prompt. Greg, this one should also be dropped from tty-next until it can be further investgated and the problem solved. Reported-by: Kevin Hilman Cc: Dmitry Fink Cc: Alexander Savchenko Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/omap-serial.c | 3 +-- include/uapi/linux/serial_reg.h | 1 - 2 files changed, 1 insertion(+), 3 deletions(-) (limited to 'include/uapi') diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index b0f46e666e1a..816d1a23f9d0 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -350,8 +350,7 @@ static void transmit_chars(struct uart_omap_port *up, unsigned int lsr) serial_omap_stop_tx(&up->port); return; } - count = up->port.fifosize - - (serial_in(up, UART_OMAP_TXFIFO_LVL) & 0xFF); + count = up->port.fifosize / 4; do { serial_out(up, UART_TX, xmit->buf[xmit->tail]); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); diff --git a/include/uapi/linux/serial_reg.h b/include/uapi/linux/serial_reg.h index 97c26beae605..e6322605b138 100644 --- a/include/uapi/linux/serial_reg.h +++ b/include/uapi/linux/serial_reg.h @@ -366,7 +366,6 @@ #define UART_OMAP_MDR1_FIR_MODE 0x05 /* FIR mode */ #define UART_OMAP_MDR1_CIR_MODE 0x06 /* CIR mode */ #define UART_OMAP_MDR1_DISABLE 0x07 /* Disable (default state) */ -#define UART_OMAP_TXFIFO_LVL 0x1A /* TX FIFO fullness */ /* * These are definitions for the Exar XR17V35X and XR17(C|D)15X -- cgit v1.2.3