From 4bf4ea9dca4ba1984abeb592f429265b9bacac42 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Tue, 30 Dec 2014 20:28:15 -0500 Subject: serial: omap_8250: Fix RTS handling The OMAP3 UART ignores MCR[1] (ie., UART_MCR_RTS) when in autoRTS mode (UPF_HARD_FLOW + CRTSCTS). This makes it impossible for either the serial core or userspace to manually flow control the sender. Disable autoRTS mode when RTS is lowered and restore the previous mode when RTS is raised. Note that the OMAP3 UART provides no mechanism for switching from autoRTS mode without corrupting incoming data; to access the necessary register, the line control settings must be set to 8-e-2 and thus any data received during that time will be interpreted with those settings. This corruption has been observed in practice. Cc: Sebastian Andrzej Siewior Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_8250.h | 1 + include/linux/serial_core.h | 1 + 2 files changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index e02acf0a0ec9..245b959f1ff6 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -126,6 +126,7 @@ extern int serial8250_do_startup(struct uart_port *port); extern void serial8250_do_shutdown(struct uart_port *port); extern void serial8250_do_pm(struct uart_port *port, unsigned int state, unsigned int oldstate); +extern void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl); extern int fsl8250_handle_irq(struct uart_port *port); int serial8250_handle_irq(struct uart_port *port, unsigned int iir); unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 057038cf2788..a0c7033d5f91 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -123,6 +123,7 @@ struct uart_port { void (*set_termios)(struct uart_port *, struct ktermios *new, struct ktermios *old); + void (*set_mctrl)(struct uart_port *, unsigned int); int (*startup)(struct uart_port *port); void (*shutdown)(struct uart_port *port); void (*throttle)(struct uart_port *port); -- cgit v1.2.3 From a291b7d5f600a068af1e2186ce590a9a39093ddb Mon Sep 17 00:00:00 2001 From: Robert Baldyga Date: Wed, 10 Dec 2014 12:49:24 +0100 Subject: serial: s3c: add missing register definitions This macro definitions are necessary to implement DMA transfers is samsung serial driver. Based on previous work of Sylwester Nawrocki and Lukasz Czerwinski. Signed-off-by: Robert Baldyga Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_s3c.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include/linux') diff --git a/include/linux/serial_s3c.h b/include/linux/serial_s3c.h index e6fc9567690b..a7f004a3c177 100644 --- a/include/linux/serial_s3c.h +++ b/include/linux/serial_s3c.h @@ -104,6 +104,31 @@ S3C2410_UCON_RXIRQMODE | \ S3C2410_UCON_RXFIFO_TOI) +#define S3C64XX_UCON_TXBURST_1 (0<<20) +#define S3C64XX_UCON_TXBURST_4 (1<<20) +#define S3C64XX_UCON_TXBURST_8 (2<<20) +#define S3C64XX_UCON_TXBURST_16 (3<<20) +#define S3C64XX_UCON_TXBURST_MASK (0xf<<20) +#define S3C64XX_UCON_RXBURST_1 (0<<16) +#define S3C64XX_UCON_RXBURST_4 (1<<16) +#define S3C64XX_UCON_RXBURST_8 (2<<16) +#define S3C64XX_UCON_RXBURST_16 (3<<16) +#define S3C64XX_UCON_RXBURST_MASK (0xf<<16) +#define S3C64XX_UCON_TIMEOUT_SHIFT (12) +#define S3C64XX_UCON_TIMEOUT_MASK (0xf<<12) +#define S3C64XX_UCON_EMPTYINT_EN (1<<11) +#define S3C64XX_UCON_DMASUS_EN (1<<10) +#define S3C64XX_UCON_TXINT_LEVEL (1<<9) +#define S3C64XX_UCON_RXINT_LEVEL (1<<8) +#define S3C64XX_UCON_TIMEOUT_EN (1<<7) +#define S3C64XX_UCON_ERRINT_EN (1<<6) +#define S3C64XX_UCON_TXMODE_DMA (2<<2) +#define S3C64XX_UCON_TXMODE_CPU (1<<2) +#define S3C64XX_UCON_TXMODE_MASK (3<<2) +#define S3C64XX_UCON_RXMODE_DMA (2<<0) +#define S3C64XX_UCON_RXMODE_CPU (1<<0) +#define S3C64XX_UCON_RXMODE_MASK (3<<0) + #define S3C2410_UFCON_FIFOMODE (1<<0) #define S3C2410_UFCON_TXTRIG0 (0<<6) #define S3C2410_UFCON_RXTRIG8 (1<<4) @@ -155,6 +180,7 @@ #define S3C2440_UFSTAT_TXMASK (63<<8) #define S3C2440_UFSTAT_RXMASK (63) +#define S3C2410_UTRSTAT_TIMEOUT (1<<3) #define S3C2410_UTRSTAT_TXE (1<<2) #define S3C2410_UTRSTAT_TXFE (1<<1) #define S3C2410_UTRSTAT_RXDR (1<<0) @@ -179,8 +205,10 @@ #define S3C64XX_UINTM 0x38 #define S3C64XX_UINTM_RXD (0) +#define S3C64XX_UINTM_ERROR (1) #define S3C64XX_UINTM_TXD (2) #define S3C64XX_UINTM_RXD_MSK (1 << S3C64XX_UINTM_RXD) +#define S3C64XX_UINTM_ERR_MSK (1 << S3C64XX_UINTM_ERROR) #define S3C64XX_UINTM_TXD_MSK (1 << S3C64XX_UINTM_TXD) /* Following are specific to S5PV210 */ -- cgit v1.2.3 From 67dc0d4758e5ced978bb30e8af11bc42cabfa77c Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Thu, 29 Jan 2015 14:11:25 +1000 Subject: vt_buffer: drop console buffer copying optimisations These two copy to/from VGA memory, however on the Silicon Motion SMI750 VGA card on a 64-bit system cause console corruption. This is due to the hw being buggy and not handling a 64-bit transaction correctly. We could try and create a 32-bit version of these routines, but I'm not sure the optimisation is worth much today. Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1132826 Tested-by: Huawei engineering. Signed-off-by: Dave Airlie Cc: Linus Torvalds Cc: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- include/linux/vt_buffer.h | 4 ---- 1 file changed, 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/vt_buffer.h b/include/linux/vt_buffer.h index 057db7d2f448..f38c10ba3ff5 100644 --- a/include/linux/vt_buffer.h +++ b/include/linux/vt_buffer.h @@ -21,10 +21,6 @@ #ifndef VT_BUF_HAVE_RW #define scr_writew(val, addr) (*(addr) = (val)) #define scr_readw(addr) (*(addr)) -#define scr_memcpyw(d, s, c) memcpy(d, s, c) -#define scr_memmovew(d, s, c) memmove(d, s, c) -#define VT_BUF_HAVE_MEMCPYW -#define VT_BUF_HAVE_MEMMOVEW #endif #ifndef VT_BUF_HAVE_MEMSETW -- cgit v1.2.3 From 01395d798452435f19de3bfe5d04325db4e49677 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Thu, 22 Jan 2015 11:50:24 -0500 Subject: PNP: Allow console to override ACPI device sleep If the serial console is an ACPI PNP device, the PNP bus always powers down the device at system suspend, even though the no_console_suspend command line parameter is specified (eg., when debugging suspend/resume). Add PNP_CONSOLE capability, which when set, prevents calling both the ->disable() and ->suspend() PNP protocol methods if console suspend is disabled. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/pnp/driver.c | 2 +- include/linux/pnp.h | 12 ++++++++++-- 2 files changed, 11 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/drivers/pnp/driver.c b/drivers/pnp/driver.c index f748cc8cbb03..4e57d3370368 100644 --- a/drivers/pnp/driver.c +++ b/drivers/pnp/driver.c @@ -182,7 +182,7 @@ static int __pnp_bus_suspend(struct device *dev, pm_message_t state) return error; } - if (pnp_dev->protocol->suspend) + if (pnp_can_suspend(pnp_dev)) pnp_dev->protocol->suspend(pnp_dev, state); return 0; } diff --git a/include/linux/pnp.h b/include/linux/pnp.h index 195aafc6cd07..6512e9cbc6d5 100644 --- a/include/linux/pnp.h +++ b/include/linux/pnp.h @@ -12,6 +12,7 @@ #include #include #include +#include #define PNP_NAME_LEN 50 @@ -309,15 +310,22 @@ struct pnp_fixup { #define PNP_DISABLE 0x0004 #define PNP_CONFIGURABLE 0x0008 #define PNP_REMOVABLE 0x0010 +#define PNP_CONSOLE 0x0020 #define pnp_can_read(dev) (((dev)->protocol->get) && \ ((dev)->capabilities & PNP_READ)) #define pnp_can_write(dev) (((dev)->protocol->set) && \ ((dev)->capabilities & PNP_WRITE)) -#define pnp_can_disable(dev) (((dev)->protocol->disable) && \ - ((dev)->capabilities & PNP_DISABLE)) +#define pnp_can_disable(dev) (((dev)->protocol->disable) && \ + ((dev)->capabilities & PNP_DISABLE) && \ + (!((dev)->capabilities & PNP_CONSOLE) || \ + console_suspend_enabled)) #define pnp_can_configure(dev) ((!(dev)->active) && \ ((dev)->capabilities & PNP_CONFIGURABLE)) +#define pnp_can_suspend(dev) (((dev)->protocol->suspend) && \ + (!((dev)->capabilities & PNP_CONSOLE) || \ + console_suspend_enabled)) + #ifdef CONFIG_ISAPNP extern struct pnp_protocol isapnp_protocol; -- cgit v1.2.3 From 3abf87cd3e70009ed70a7f28c2914888a7e27332 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 17 Jan 2015 15:42:04 -0500 Subject: tty: Make lock subclasses available for other tty locks Besides nested legacy_mutex locking which is required on pty pair teardown, other nested pty operations require lock subclassing. Move lock subclass definition to tty interface header, include/linux/tty.h, and document its use. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_mutex.c | 12 +----------- include/linux/tty.h | 17 +++++++++++++++++ 2 files changed, 18 insertions(+), 11 deletions(-) (limited to 'include/linux') diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index a872389dc0bc..0efcf713b756 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -4,18 +4,8 @@ #include #include -/* - * Nested tty locks are necessary for releasing pty pairs. - * The stable lock order is master pty first, then slave pty. - */ - /* Legacy tty mutex glue */ -enum { - TTY_MUTEX_NORMAL, - TTY_MUTEX_SLAVE, -}; - /* * Getting the big tty mutex. */ @@ -58,5 +48,5 @@ void __lockfunc tty_unlock_slave(struct tty_struct *tty) void tty_set_lock_subclass(struct tty_struct *tty) { - lockdep_set_subclass(&tty->legacy_mutex, TTY_MUTEX_SLAVE); + lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE); } diff --git a/include/linux/tty.h b/include/linux/tty.h index 7d66ae508e5c..849659908f23 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -14,6 +14,23 @@ #include +/* + * Lock subclasses for tty locks + * + * TTY_LOCK_NORMAL is for normal ttys and master ptys. + * TTY_LOCK_SLAVE is for slave ptys only. + * + * Lock subclasses are necessary for handling nested locking with pty pairs. + * tty locks which use nested locking: + * + * legacy_mutex - Nested tty locks are necessary for releasing pty pairs. + * The stable lock order is master pty first, then slave pty. + */ + +enum { + TTY_LOCK_NORMAL = 0, + TTY_LOCK_SLAVE, +}; /* * (Note: the *_driver.minor_start values 1, 64, 128, 192 are -- cgit v1.2.3 From 1d1d14da12e79a6c05fbe1a975401f0f56c93316 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 17 Jan 2015 15:42:05 -0500 Subject: pty: Fix buffer flush deadlock The pty driver does not clear its write buffer when commanded. This is to avoid an apparent deadlock between parallel flushes from both pty ends; specifically when handling either BRK or INTR input. However, parallel flushes from this source is not possible since the pty master can never be set to BRKINT or ISIG. Parallel flushes from other sources are possible but these do not threaten deadlocks. Annotate the tty buffer mutex for lockdep to represent the nested tty_buffer locking which occurs when the pty slave is processing input (its buffer mutex held) and receives INTR or BRK and acquires the linked tty buffer mutex via tty_buffer_flush(). Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/pty.c | 10 +++++++++- drivers/tty/tty_buffer.c | 6 ++++++ include/linux/tty.h | 4 ++++ 3 files changed, 19 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index f882ac81b93a..0e273158edac 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -212,10 +212,16 @@ static int pty_signal(struct tty_struct *tty, int sig) static void pty_flush_buffer(struct tty_struct *tty) { struct tty_struct *to = tty->link; + struct tty_ldisc *ld; if (!to) return; - /* tty_buffer_flush(to); FIXME */ + + ld = tty_ldisc_ref(to); + tty_buffer_flush(to, ld); + if (ld) + tty_ldisc_deref(ld); + if (to->packet) { spin_lock_irq(&tty->ctrl_lock); tty->ctrl_status |= TIOCPKT_FLUSHWRITE; @@ -425,6 +431,8 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, tty->port = ports[1]; o_tty->port->itty = o_tty; + tty_buffer_set_lock_subclass(o_tty->port); + tty_driver_kref_get(driver); tty->count++; o_tty->count++; diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 3605103fc1ac..75661641f5fe 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -557,3 +557,9 @@ int tty_buffer_set_limit(struct tty_port *port, int limit) return 0; } EXPORT_SYMBOL_GPL(tty_buffer_set_limit); + +/* slave ptys can claim nested buffer lock when handling BRK and INTR */ +void tty_buffer_set_lock_subclass(struct tty_port *port) +{ + lockdep_set_subclass(&port->buf.lock, TTY_LOCK_SLAVE); +} diff --git a/include/linux/tty.h b/include/linux/tty.h index 849659908f23..55964b9490dd 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -25,6 +25,9 @@ * * legacy_mutex - Nested tty locks are necessary for releasing pty pairs. * The stable lock order is master pty first, then slave pty. + * tty_buffer lock - slave ptys can claim nested buffer lock when handling + * signal chars. The stable lock order is slave pty, then + * master. */ enum { @@ -460,6 +463,7 @@ extern void tty_flush_to_ldisc(struct tty_struct *tty); extern void tty_buffer_free_all(struct tty_port *port); extern void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld); extern void tty_buffer_init(struct tty_port *port); +extern void tty_buffer_set_lock_subclass(struct tty_port *port); extern speed_t tty_termios_baud_rate(struct ktermios *termios); extern speed_t tty_termios_input_baud_rate(struct ktermios *termios); extern void tty_termios_encode_baud_rate(struct ktermios *termios, -- cgit v1.2.3 From d2b6f44779d3be22d32a5697bd30b59367fd2b33 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 17 Jan 2015 15:42:06 -0500 Subject: n_tty: Fix signal handling flushes BRKINT and ISIG requires input and output flush when a signal char is received. However, the order of operations is significant since parallel i/o may be ongoing. Merge the signal handling for BRKINT with ISIG handling. Process the signal first. This ensures any ongoing i/o is aborted; without this, a waiting writer may continue writing after the flush occurs and after the signal char has been echoed. Write lock the termios_rwsem, which excludes parallel writers from pushing new i/o until after the output buffers are flushed; claiming the write lock is necessary anyway to exclude parallel readers while the read buffer is flushed. Subclass the termios_rwsem for ptys since the slave pty performing the flush may appear to reorder the termios_rwsem->tty buffer lock lock order; adding annotation clarifies that slave tty_buffer lock-> slave termios_rwsem -> master tty_buffer lock is a valid lock order. Flush the echo buffer. In this context, the echo buffer is 'output'. Otherwise, the output will appear discontinuous because the output buffer was cleared which contains older output than the echo buffer. Open-code the read buffer flush since the input worker does not need kicking (this is the input worker). Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_tty.c | 45 ++++++++++++++++++++++++++++++--------------- drivers/tty/pty.c | 1 + include/linux/tty.h | 3 +++ 3 files changed, 34 insertions(+), 15 deletions(-) (limited to 'include/linux') diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 5793aa0d3bfb..cf6e0f2e1331 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -1090,16 +1090,45 @@ static void eraser(unsigned char c, struct tty_struct *tty) * Called when a signal is being sent due to terminal input. * Called from the driver receive_buf path so serialized. * + * Performs input and output flush if !NOFLSH. In this context, the echo + * buffer is 'output'. The signal is processed first to alert any current + * readers or writers to discontinue and exit their i/o loops. + * * Locking: ctrl_lock */ static void isig(int sig, struct tty_struct *tty) { + struct n_tty_data *ldata = tty->disc_data; struct pid *tty_pgrp = tty_get_pgrp(tty); if (tty_pgrp) { kill_pgrp(tty_pgrp, sig, 1); put_pid(tty_pgrp); } + + if (!L_NOFLSH(tty)) { + up_read(&tty->termios_rwsem); + down_write(&tty->termios_rwsem); + + /* clear echo buffer */ + mutex_lock(&ldata->output_lock); + ldata->echo_head = ldata->echo_tail = 0; + ldata->echo_mark = ldata->echo_commit = 0; + mutex_unlock(&ldata->output_lock); + + /* clear output buffer */ + tty_driver_flush_buffer(tty); + + /* clear input buffer */ + reset_buffer_flags(tty->disc_data); + + /* notify pty master of flush */ + if (tty->link) + n_tty_packet_mode_flush(tty); + + up_write(&tty->termios_rwsem); + down_read(&tty->termios_rwsem); + } } /** @@ -1123,13 +1152,6 @@ static void n_tty_receive_break(struct tty_struct *tty) return; if (I_BRKINT(tty)) { isig(SIGINT, tty); - if (!L_NOFLSH(tty)) { - /* flushing needs exclusive termios_rwsem */ - up_read(&tty->termios_rwsem); - n_tty_flush_buffer(tty); - tty_driver_flush_buffer(tty); - down_read(&tty->termios_rwsem); - } return; } if (I_PARMRK(tty)) { @@ -1203,13 +1225,7 @@ static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c) static void n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) { - if (!L_NOFLSH(tty)) { - /* flushing needs exclusive termios_rwsem */ - up_read(&tty->termios_rwsem); - n_tty_flush_buffer(tty); - tty_driver_flush_buffer(tty); - down_read(&tty->termios_rwsem); - } + isig(signal, tty); if (I_IXON(tty)) start_tty(tty); if (L_ECHO(tty)) { @@ -1217,7 +1233,6 @@ n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c) commit_echoes(tty); } else process_echoes(tty); - isig(signal, tty); return; } diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index 0e273158edac..e72ee629cead 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -395,6 +395,7 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, goto err_put_module; tty_set_lock_subclass(o_tty); + lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE); if (legacy) { /* We always use new tty termios data so we can do this diff --git a/include/linux/tty.h b/include/linux/tty.h index 55964b9490dd..fe5623c9af71 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -25,6 +25,9 @@ * * legacy_mutex - Nested tty locks are necessary for releasing pty pairs. * The stable lock order is master pty first, then slave pty. + * termios_rwsem - The stable lock order is tty_buffer lock->termios_rwsem. + * Subclassing this lock enables the slave pty to hold its + * termios_rwsem when claiming the master tty_buffer lock. * tty_buffer lock - slave ptys can claim nested buffer lock when handling * signal chars. The stable lock order is slave pty, then * master. -- cgit v1.2.3 From 4516d50aabedbe5ae334155193e4d35c02390d9a Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Thu, 22 Jan 2015 12:24:30 -0500 Subject: serial: 8250: Use canary to restart console after suspend When using no_console_suspend, the serial console may be powered off anyway during system sleep. Upon resume, the port may be in its default power-on state, but is expected to continue console i/o before the device has received its pm callback. The resultant garbage i/o can cause all kinds of havoc on the remote end. Use the scratch register as a canary to discover if the console has been powered-off. Write a non-zero value to the scratch register at port suspend and reprogram the port before any console i/o if the scratch register != canary before port resume. This workaround is disabled for omap_8250 (which uses different divisor programming). Credit to Doug Anderson for the idea of using the scratch register canary to discover port power-down. Cc: Doug Anderson Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_core.c | 35 ++++++++++++++++++++++++++++++++++- include/linux/serial_8250.h | 3 +++ 2 files changed, 37 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index c8ecfaf49eb4..1449c56506b7 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -3267,6 +3267,27 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count) else serial_port_out(port, UART_IER, 0); + /* check scratch reg to see if port powered off during system sleep */ + if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) { + struct ktermios termios; + unsigned int baud, quot, frac = 0; + + termios.c_cflag = port->cons->cflag; + if (port->state->port.tty && termios.c_cflag == 0) + termios.c_cflag = port->state->port.tty->termios.c_cflag; + + baud = uart_get_baud_rate(port, &termios, NULL, + port->uartclk / 16 / 0xffff, + port->uartclk / 16); + quot = serial8250_get_divisor(up, baud, &frac); + + serial8250_set_divisor(port, baud, quot, frac); + serial_port_out(port, UART_LCR, up->lcr); + serial_port_out(port, UART_MCR, UART_MCR_DTR | UART_MCR_RTS); + + up->canary = 0; + } + uart_console_write(port, s, count, serial8250_console_putchar); /* @@ -3417,7 +3438,17 @@ int __init early_serial_setup(struct uart_port *port) */ void serial8250_suspend_port(int line) { - uart_suspend_port(&serial8250_reg, &serial8250_ports[line].port); + struct uart_8250_port *up = &serial8250_ports[line]; + struct uart_port *port = &up->port; + + if (!console_suspend_enabled && uart_console(port) && + port->type != PORT_8250) { + unsigned char canary = 0xa5; + serial_out(up, UART_SCR, canary); + up->canary = canary; + } + + uart_suspend_port(&serial8250_reg, port); } /** @@ -3431,6 +3462,8 @@ void serial8250_resume_port(int line) struct uart_8250_port *up = &serial8250_ports[line]; struct uart_port *port = &up->port; + up->canary = 0; + if (up->capabilities & UART_NATSEMI) { /* Ensure it's still in high speed mode */ serial_port_out(port, UART_LCR, 0xE0); diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index 245b959f1ff6..a8efa235b7c1 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -85,6 +85,9 @@ struct uart_8250_port { unsigned char mcr_force; /* mask of forced bits */ unsigned char cur_iotype; /* Running I/O type */ unsigned int rpm_tx_active; + unsigned char canary; /* non-zero during system sleep + * if no_console_suspend + */ /* * Some bits in registers are cleared on a read, so they must -- cgit v1.2.3 From 391f93f2ec9f857c83bdd21a14dcf7e699f38579 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 25 Jan 2015 14:44:51 -0500 Subject: serial: core: Rework hw-assisted flow control support hw-assisted flow control support was added to the serial core in v3.8 with commits, dba05832cbe4f ("SERIAL: core: add hardware assisted h/w flow control support") 2cbacafd7af0f ("SERIAL: core: add hardware assisted s/w flow control support") 9aba8d5b01119 ("SERIAL: core: add throttle/unthrottle callbacks for hardware assisted flow control") Since then, additional requirements for serial core support have arisen. Specifically, 1. Separate tx and rx flow control settings for UARTs which only support tx flow control (ie., autoCTS). 2. Disable sw-assisted CTS flow control in autoCTS mode 3. Support for RTS flow control by serial core and userspace in autoRTS mode Distinguish mode from capability; introduce UPSTAT_AUTORTS, UPSTAT_AUTOCTS and UPSTAT_AUTOXOFF which, when set by the uart driver, enable serial core support for hw-assisted rx, hw-assisted tx and hw-assisted in-band/IXOFF rx flow control, respectively. [Note: hw-assisted in-band/IXON tx flow control does not require serial core support/intervention and can be enabled by the uart driver when required.] These modes must be set/reset in the driver's set_termios() method, based on termios settings, and thus can be safely queried in any context in which one of the port lock, port mutex or termios rwsem are held. Set these modes in the 2 in-tree drivers, omap-serial and 8250_omap, which currently use UPF_HARD_FLOW/UPF_SOFT_FLOW support. Retain UPF_HARD_FLOW and UPF_SOFT_FLOW as capabilities; re-define UPF_HARD_FLOW as both UPF_AUTO_RTS and UPF_AUTO_CTS to allow for distinct and separate rx and tx flow control capabilities. Disable sw-assisted CTS flow control when UPSTAT_AUTOCTS is enabled. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_omap.c | 7 +++- drivers/tty/serial/omap-serial.c | 7 +++- drivers/tty/serial/serial_core.c | 76 ++++++++++++++----------------------- include/linux/serial_core.h | 21 ++++++++-- 4 files changed, 59 insertions(+), 52 deletions(-) (limited to 'include/linux') diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index 9191d05cfaf0..6e4ff7148ead 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -421,8 +421,11 @@ static void omap_8250_set_termios(struct uart_port *port, priv->efr = 0; up->mcr &= ~(UART_MCR_RTS | UART_MCR_XONANY); + up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF); + if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) { /* Enable AUTORTS and AUTOCTS */ + up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; priv->efr |= UART_EFR_CTS | UART_EFR_RTS; } else if (up->port.flags & UPF_SOFT_FLOW) { /* @@ -438,8 +441,10 @@ static void omap_8250_set_termios(struct uart_port *port, * Enable XON/XOFF flow control on output. * Transmit XON1, XOFF1 */ - if (termios->c_iflag & IXOFF) + if (termios->c_iflag & IXOFF) { + up->port.status |= UPSTAT_AUTOXOFF; priv->efr |= OMAP_UART_SW_TX; + } /* * IXANY Flag: diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index b1cf9a3b673a..6129fe515932 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -1053,8 +1053,11 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios, serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_TRIG); + up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF); + if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) { /* Enable AUTORTS and AUTOCTS */ + up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; up->efr |= UART_EFR_CTS | UART_EFR_RTS; /* Ensure MCR RTS is asserted */ @@ -1081,8 +1084,10 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios, * Enable XON/XOFF flow control on output. * Transmit XON1, XOFF1 */ - if (termios->c_iflag & IXOFF) + if (termios->c_iflag & IXOFF) { + up->port.status |= UPSTAT_AUTOXOFF; up->efr |= OMAP_UART_SW_TX; + } /* * IXANY Flag: diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 2c67a077042a..6a1055ae3437 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -179,14 +179,6 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state, if (tty->termios.c_cflag & CBAUD) uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR); } - - spin_lock_irq(&uport->lock); - if (uart_cts_enabled(uport) && - !(uport->ops->get_mctrl(uport) & TIOCM_CTS)) - uport->hw_stopped = 1; - else - uport->hw_stopped = 0; - spin_unlock_irq(&uport->lock); } /* @@ -442,6 +434,7 @@ static void uart_change_speed(struct tty_struct *tty, struct uart_state *state, { struct uart_port *uport = state->uart_port; struct ktermios *termios; + int hw_stopped; /* * If we have no tty, termios, or the port does not exist, @@ -466,6 +459,18 @@ static void uart_change_speed(struct tty_struct *tty, struct uart_state *state, uport->status &= ~UPSTAT_DCD_ENABLE; else uport->status |= UPSTAT_DCD_ENABLE; + + /* reset sw-assisted CTS flow control based on (possibly) new mode */ + hw_stopped = uport->hw_stopped; + uport->hw_stopped = uart_softcts_mode(uport) && + !(uport->ops->get_mctrl(uport) & TIOCM_CTS); + if (uport->hw_stopped) { + if (!hw_stopped) + uport->ops->stop_tx(uport); + } else { + if (hw_stopped) + __uart_start(tty); + } spin_unlock_irq(&uport->lock); } @@ -619,22 +624,22 @@ static void uart_throttle(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; struct uart_port *port = state->uart_port; - upf_t mask = 0; + upstat_t mask = 0; if (I_IXOFF(tty)) - mask |= UPF_SOFT_FLOW; + mask |= UPSTAT_AUTOXOFF; if (tty->termios.c_cflag & CRTSCTS) - mask |= UPF_HARD_FLOW; + mask |= UPSTAT_AUTORTS; - if (port->flags & mask) { + if (port->status & mask) { port->ops->throttle(port); - mask &= ~port->flags; + mask &= ~port->status; } - if (mask & UPF_SOFT_FLOW) + if (mask & UPSTAT_AUTOXOFF) uart_send_xchar(tty, STOP_CHAR(tty)); - if (mask & UPF_HARD_FLOW) + if (mask & UPSTAT_AUTORTS) uart_clear_mctrl(port, TIOCM_RTS); } @@ -642,22 +647,22 @@ static void uart_unthrottle(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; struct uart_port *port = state->uart_port; - upf_t mask = 0; + upstat_t mask = 0; if (I_IXOFF(tty)) - mask |= UPF_SOFT_FLOW; + mask |= UPSTAT_AUTOXOFF; if (tty->termios.c_cflag & CRTSCTS) - mask |= UPF_HARD_FLOW; + mask |= UPSTAT_AUTORTS; - if (port->flags & mask) { + if (port->status & mask) { port->ops->unthrottle(port); - mask &= ~port->flags; + mask &= ~port->status; } - if (mask & UPF_SOFT_FLOW) + if (mask & UPSTAT_AUTOXOFF) uart_send_xchar(tty, START_CHAR(tty)); - if (mask & UPF_HARD_FLOW) + if (mask & UPSTAT_AUTORTS) uart_set_mctrl(port, TIOCM_RTS); } @@ -1351,30 +1356,6 @@ static void uart_set_termios(struct tty_struct *tty, mask |= TIOCM_RTS; uart_set_mctrl(uport, mask); } - - /* - * If the port is doing h/w assisted flow control, do nothing. - * We assume that port->hw_stopped has never been set. - */ - if (uport->flags & UPF_HARD_FLOW) - return; - - /* Handle turning off CRTSCTS */ - if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) { - spin_lock_irq(&uport->lock); - uport->hw_stopped = 0; - __uart_start(tty); - spin_unlock_irq(&uport->lock); - } - /* Handle turning on CRTSCTS */ - else if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) { - spin_lock_irq(&uport->lock); - if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS)) { - uport->hw_stopped = 1; - uport->ops->stop_tx(uport); - } - spin_unlock_irq(&uport->lock); - } } /* @@ -2855,7 +2836,7 @@ void uart_handle_cts_change(struct uart_port *uport, unsigned int status) uport->icount.cts++; - if (uart_cts_enabled(uport)) { + if (uart_softcts_mode(uport)) { if (uport->hw_stopped) { if (status) { uport->hw_stopped = 0; @@ -2868,6 +2849,7 @@ void uart_handle_cts_change(struct uart_port *uport, unsigned int status) uport->ops->stop_tx(uport); } } + } } EXPORT_SYMBOL_GPL(uart_handle_cts_change); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index a0c7033d5f91..baf3e1d08416 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -191,8 +191,10 @@ struct uart_port { #define UPF_NO_TXEN_TEST ((__force upf_t) (1 << 15)) #define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ ) -/* Port has hardware-assisted h/w flow control (iow, auto-RTS *not* auto-CTS) */ -#define UPF_HARD_FLOW ((__force upf_t) (1 << 21)) +/* Port has hardware-assisted h/w flow control */ +#define UPF_AUTO_CTS ((__force upf_t) (1 << 20)) +#define UPF_AUTO_RTS ((__force upf_t) (1 << 21)) +#define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS)) /* Port has hardware-assisted s/w flow control */ #define UPF_SOFT_FLOW ((__force upf_t) (1 << 22)) #define UPF_CONS_FLOW ((__force upf_t) (1 << 23)) @@ -214,11 +216,17 @@ struct uart_port { #error Change mask not equivalent to userspace-visible bit defines #endif - /* status must be updated while holding port lock */ + /* + * Must hold termios_rwsem, port mutex and port lock to change; + * can hold any one lock to read. + */ upstat_t status; #define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0)) #define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1)) +#define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2)) +#define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3)) +#define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4)) int hw_stopped; /* sw-assisted CTS flow state */ unsigned int mctrl; /* current modem ctrl settings */ @@ -392,6 +400,13 @@ static inline bool uart_cts_enabled(struct uart_port *uport) return !!(uport->status & UPSTAT_CTS_ENABLE); } +static inline bool uart_softcts_mode(struct uart_port *uport) +{ + upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS; + + return ((uport->status & mask) == UPSTAT_CTS_ENABLE); +} + /* * The following are helper functions for the low level drivers. */ -- cgit v1.2.3 From 632f32e2107d37598e3f6816dcf00c7cab4081ca Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 25 Jan 2015 14:44:54 -0500 Subject: tty: Remove external interface for tty_set_termios() tty_set_termios() is an internal helper intended for file scope use. UART drivers which are capable of driving the RTS pin must properly handle the tiocmset() method, regardless of termios settings. A failure to do so is a UART driver bug and should be fixed there. Do not use this interface to workaround UART driver bugs. Cc: Johan Hedberg Cc: Signed-off-by: Peter Hurley Acked-by: Marcel Holtmann Signed-off-by: Greg Kroah-Hartman --- drivers/bluetooth/hci_ath.c | 15 ++------------- drivers/tty/tty_ioctl.c | 3 +-- include/linux/tty.h | 1 - 3 files changed, 3 insertions(+), 16 deletions(-) (limited to 'include/linux') diff --git a/drivers/bluetooth/hci_ath.c b/drivers/bluetooth/hci_ath.c index 2ff6dfd2d3f0..9c4dcf4c62ea 100644 --- a/drivers/bluetooth/hci_ath.c +++ b/drivers/bluetooth/hci_ath.c @@ -51,33 +51,22 @@ struct ath_struct { static int ath_wakeup_ar3k(struct tty_struct *tty) { - struct ktermios ktermios; int status = tty->driver->ops->tiocmget(tty); if (status & TIOCM_CTS) return status; - /* Disable Automatic RTSCTS */ - ktermios = tty->termios; - ktermios.c_cflag &= ~CRTSCTS; - tty_set_termios(tty, &ktermios); - /* Clear RTS first */ - status = tty->driver->ops->tiocmget(tty); + tty->driver->ops->tiocmget(tty); tty->driver->ops->tiocmset(tty, 0x00, TIOCM_RTS); mdelay(20); /* Set RTS, wake up board */ - status = tty->driver->ops->tiocmget(tty); + tty->driver->ops->tiocmget(tty); tty->driver->ops->tiocmset(tty, TIOCM_RTS, 0x00); mdelay(20); status = tty->driver->ops->tiocmget(tty); - - /* Enable Automatic RTSCTS */ - ktermios.c_cflag |= CRTSCTS; - status = tty_set_termios(tty, &ktermios); - return status; } diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c index 1787fa4d9448..a5cf253b2544 100644 --- a/drivers/tty/tty_ioctl.c +++ b/drivers/tty/tty_ioctl.c @@ -530,7 +530,7 @@ EXPORT_SYMBOL(tty_termios_hw_change); * Locking: termios_rwsem */ -int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios) +static int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios) { struct ktermios old_termios; struct tty_ldisc *ld; @@ -563,7 +563,6 @@ int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios) up_write(&tty->termios_rwsem); return 0; } -EXPORT_SYMBOL_GPL(tty_set_termios); /** * set_termios - set termios values for a tty diff --git a/include/linux/tty.h b/include/linux/tty.h index fe5623c9af71..358a337af598 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -491,7 +491,6 @@ static inline speed_t tty_get_baud_rate(struct tty_struct *tty) extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old); extern int tty_termios_hw_change(struct ktermios *a, struct ktermios *b); -extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt); extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *); extern void tty_ldisc_deref(struct tty_ldisc *); -- cgit v1.2.3