diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-tty | 16 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250.h | 2 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250_core.c | 173 | ||||
| -rw-r--r-- | include/linux/serial_8250.h | 2 | ||||
| -rw-r--r-- | include/uapi/linux/serial_reg.h | 5 |
5 files changed, 183 insertions, 15 deletions
diff --git a/Documentation/ABI/testing/sysfs-tty b/Documentation/ABI/testing/sysfs-tty index ad22fb0ee765..9eb3c2b6b040 100644 --- a/Documentation/ABI/testing/sysfs-tty +++ b/Documentation/ABI/testing/sysfs-tty @@ -138,3 +138,19 @@ Description: These sysfs values expose the TIOCGSERIAL interface via sysfs rather than via ioctls. + +What: /sys/class/tty/ttyS0/rx_trig_bytes +Date: May 2014 +Contact: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com> +Description: + Shows current RX interrupt trigger bytes or sets the + user specified value to change it for the FIFO buffer. + Users can show or set this value regardless of opening the + serial device file or not. + + The RX trigger can be set one of four kinds of values for UART + serials. When users input a meaning less value to this I/F, + the RX trigger is changed to the nearest lower value for the + device specification. For example, when user sets 7bytes on + 16550A, which has 1/4/8/14 bytes trigger, the RX trigger is + automatically changed to 4 bytes. diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index 1ebf8538b4fa..1b08c918cd51 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -12,6 +12,7 @@ */ #include <linux/serial_8250.h> +#include <linux/serial_reg.h> #include <linux/dmaengine.h> struct uart_8250_dma { @@ -60,6 +61,7 @@ struct serial8250_config { unsigned short fifo_size; unsigned short tx_loadsz; unsigned char fcr; + unsigned char rxtrig_bytes[UART_FCR_R_TRIG_MAX_STATE]; unsigned int flags; }; diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 0da01458816e..1d42dba6121d 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -31,7 +31,6 @@ #include <linux/tty.h> #include <linux/ratelimit.h> #include <linux/tty_flip.h> -#include <linux/serial_reg.h> #include <linux/serial_core.h> #include <linux/serial.h> #include <linux/serial_8250.h> @@ -161,6 +160,7 @@ static const struct serial8250_config uart_config[] = { .fifo_size = 16, .tx_loadsz = 16, .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .rxtrig_bytes = {1, 4, 8, 14}, .flags = UART_CAP_FIFO, }, [PORT_CIRRUS] = { @@ -180,6 +180,7 @@ static const struct serial8250_config uart_config[] = { .tx_loadsz = 16, .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 | UART_FCR_T_TRIG_00, + .rxtrig_bytes = {8, 16, 24, 28}, .flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP, }, [PORT_16750] = { @@ -188,6 +189,7 @@ static const struct serial8250_config uart_config[] = { .tx_loadsz = 64, .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 | UART_FCR7_64BYTE, + .rxtrig_bytes = {1, 16, 32, 56}, .flags = UART_CAP_FIFO | UART_CAP_SLEEP | UART_CAP_AFE, }, [PORT_STARTECH] = { @@ -209,6 +211,7 @@ static const struct serial8250_config uart_config[] = { .tx_loadsz = 32, .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 | UART_FCR_T_TRIG_10, + .rxtrig_bytes = {8, 16, 56, 60}, .flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP, }, [PORT_16850] = { @@ -266,6 +269,7 @@ static const struct serial8250_config uart_config[] = { .tx_loadsz = 8, .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 | UART_FCR_T_TRIG_01, + .rxtrig_bytes = {1, 4, 8, 14}, .flags = UART_CAP_FIFO | UART_CAP_RTOIE, }, [PORT_XR17D15X] = { @@ -530,11 +534,8 @@ static void serial8250_clear_fifos(struct uart_8250_port *p) void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p) { - unsigned char fcr; - serial8250_clear_fifos(p); - fcr = uart_config[p->port.type].fcr; - serial_out(p, UART_FCR, fcr); + serial_out(p, UART_FCR, p->fcr); } EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos); @@ -2256,10 +2257,9 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { struct uart_8250_port *up = up_to_u8250p(port); - unsigned char cval, fcr = 0; + unsigned char cval; unsigned long flags; unsigned int baud, quot; - int fifo_bug = 0; switch (termios->c_cflag & CSIZE) { case CS5: @@ -2282,7 +2282,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, if (termios->c_cflag & PARENB) { cval |= UART_LCR_PARITY; if (up->bugs & UART_BUG_PARITY) - fifo_bug = 1; + up->fifo_bug = true; } if (!(termios->c_cflag & PARODD)) cval |= UART_LCR_EPAR; @@ -2306,10 +2306,10 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, quot++; if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) { - fcr = uart_config[port->type].fcr; - if ((baud < 2400 && !up->dma) || fifo_bug) { - fcr &= ~UART_FCR_TRIGGER_MASK; - fcr |= UART_FCR_TRIGGER_1; + /* NOTE: If fifo_bug is not set, a user can set RX_trigger. */ + if ((baud < 2400 && !up->dma) || up->fifo_bug) { + up->fcr &= ~UART_FCR_TRIGGER_MASK; + up->fcr |= UART_FCR_TRIGGER_1; } } @@ -2442,15 +2442,15 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, * is written without DLAB set, this mode will be disabled. */ if (port->type == PORT_16750) - serial_port_out(port, UART_FCR, fcr); + serial_port_out(port, UART_FCR, up->fcr); serial_port_out(port, UART_LCR, cval); /* reset DLAB */ up->lcr = cval; /* Save LCR */ if (port->type != PORT_16750) { /* emulated UARTs (Lucent Venus 167x) need two steps */ - if (fcr & UART_FCR_ENABLE_FIFO) + if (up->fcr & UART_FCR_ENABLE_FIFO) serial_port_out(port, UART_FCR, UART_FCR_ENABLE_FIFO); - serial_port_out(port, UART_FCR, fcr); /* set fcr */ + serial_port_out(port, UART_FCR, up->fcr); /* set fcr */ } serial8250_set_mctrl(port, port->mctrl); spin_unlock_irqrestore(&port->lock, flags); @@ -2640,6 +2640,146 @@ static int serial8250_request_port(struct uart_port *port) return ret; } +static int fcr_get_rxtrig_bytes(struct uart_8250_port *up) +{ + const struct serial8250_config *conf_type = &uart_config[up->port.type]; + unsigned char bytes; + + bytes = conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(up->fcr)]; + + return bytes ? bytes : -EOPNOTSUPP; +} + +static int bytes_to_fcr_rxtrig(struct uart_8250_port *up, unsigned char bytes) +{ + const struct serial8250_config *conf_type = &uart_config[up->port.type]; + int i; + + if (!conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(UART_FCR_R_TRIG_00)]) + return -EOPNOTSUPP; + + for (i = 1; i < UART_FCR_R_TRIG_MAX_STATE; i++) { + if (bytes < conf_type->rxtrig_bytes[i]) + /* Use the nearest lower value */ + return (--i) << UART_FCR_R_TRIG_SHIFT; + } + + return UART_FCR_R_TRIG_11; +} + +static int do_get_rxtrig(struct tty_port *port) +{ + struct uart_state *state = container_of(port, struct uart_state, port); + struct uart_port *uport = state->uart_port; + struct uart_8250_port *up = + container_of(uport, struct uart_8250_port, port); + + if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1) + return -EINVAL; + + return fcr_get_rxtrig_bytes(up); +} + +static int do_serial8250_get_rxtrig(struct tty_port *port) +{ + int rxtrig_bytes; + + mutex_lock(&port->mutex); + rxtrig_bytes = do_get_rxtrig(port); + mutex_unlock(&port->mutex); + + return rxtrig_bytes; +} + +static ssize_t serial8250_get_attr_rx_trig_bytes(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct tty_port *port = dev_get_drvdata(dev); + int rxtrig_bytes; + + rxtrig_bytes = do_serial8250_get_rxtrig(port); + if (rxtrig_bytes < 0) + return rxtrig_bytes; + + return snprintf(buf, PAGE_SIZE, "%d\n", rxtrig_bytes); +} + +static int do_set_rxtrig(struct tty_port *port, unsigned char bytes) +{ + struct uart_state *state = container_of(port, struct uart_state, port); + struct uart_port *uport = state->uart_port; + struct uart_8250_port *up = + container_of(uport, struct uart_8250_port, port); + int rxtrig; + + if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1 || + up->fifo_bug) + return -EINVAL; + + rxtrig = bytes_to_fcr_rxtrig(up, bytes); + if (rxtrig < 0) + return rxtrig; + + serial8250_clear_fifos(up); + up->fcr &= ~UART_FCR_TRIGGER_MASK; + up->fcr |= (unsigned char)rxtrig; + serial_out(up, UART_FCR, up->fcr); + return 0; +} + +static int do_serial8250_set_rxtrig(struct tty_port *port, unsigned char bytes) +{ + int ret; + + mutex_lock(&port->mutex); + ret = do_set_rxtrig(port, bytes); + mutex_unlock(&port->mutex); + + return ret; +} + +static ssize_t serial8250_set_attr_rx_trig_bytes(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct tty_port *port = dev_get_drvdata(dev); + unsigned char bytes; + int ret; + + if (!count) + return -EINVAL; + + ret = kstrtou8(buf, 10, &bytes); + if (ret < 0) + return ret; + + ret = do_serial8250_set_rxtrig(port, bytes); + if (ret < 0) + return ret; + + return count; +} + +static DEVICE_ATTR(rx_trig_bytes, S_IRUSR | S_IWUSR | S_IRGRP, + serial8250_get_attr_rx_trig_bytes, + serial8250_set_attr_rx_trig_bytes); + +static struct attribute *serial8250_dev_attrs[] = { + &dev_attr_rx_trig_bytes.attr, + NULL, + }; + +static struct attribute_group serial8250_dev_attr_group = { + .attrs = serial8250_dev_attrs, + }; + +static void register_dev_spec_attr_grp(struct uart_8250_port *up) +{ + const struct serial8250_config *conf_type = &uart_config[up->port.type]; + + if (conf_type->rxtrig_bytes[0]) + up->port.attr_group = &serial8250_dev_attr_group; +} + static void serial8250_config_port(struct uart_port *port, int flags) { struct uart_8250_port *up = up_to_u8250p(port); @@ -2687,6 +2827,9 @@ static void serial8250_config_port(struct uart_port *port, int flags) if ((port->type == PORT_XR17V35X) || (port->type == PORT_XR17D15X)) port->handle_irq = exar_handle_irq; + + register_dev_spec_attr_grp(up); + up->fcr = uart_config[up->port.type].fcr; } static int diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index 730ab4b3d686..f93649e22c43 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -74,8 +74,10 @@ struct uart_8250_port { struct list_head list; /* ports on this IRQ */ unsigned short capabilities; /* port capabilities */ unsigned short bugs; /* port bugs */ + bool fifo_bug; /* min RX trigger if enabled */ unsigned int tx_loadsz; /* transmit fifo load size */ unsigned char acr; + unsigned char fcr; unsigned char ier; unsigned char lcr; unsigned char mcr; diff --git a/include/uapi/linux/serial_reg.h b/include/uapi/linux/serial_reg.h index 99b47058816a..df6c9ab6b0cd 100644 --- a/include/uapi/linux/serial_reg.h +++ b/include/uapi/linux/serial_reg.h @@ -88,6 +88,11 @@ #define UART_FCR6_T_TRIGGER_30 0x30 /* Mask for transmit trigger set at 30 */ #define UART_FCR7_64BYTE 0x20 /* Go into 64 byte mode (TI16C750) */ +#define UART_FCR_R_TRIG_SHIFT 6 +#define UART_FCR_R_TRIG_BITS(x) \ + (((x) & UART_FCR_TRIGGER_MASK) >> UART_FCR_R_TRIG_SHIFT) +#define UART_FCR_R_TRIG_MAX_STATE 4 + #define UART_LCR 3 /* Out: Line Control Register */ /* * Note: if the word length is 5 bits (UART_LCR_WLEN5), then setting |