From ed617e44234ee03a60edbf0809f696f0b9cf1b90 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Mon, 16 Jun 2014 09:16:58 -0400 Subject: tty: Document locking for tty driver methods The tty core calls the tty driver's open, close and hangup methods holding the tty lock. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- include/linux/tty_driver.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 756a60989294..e48c608a8fa8 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -35,14 +35,14 @@ * This routine is mandatory; if this routine is not filled in, * the attempted open will fail with ENODEV. * - * Required method. - * + * Required method. Called with tty lock held. + * * void (*close)(struct tty_struct * tty, struct file * filp); * * This routine is called when a particular tty device is closed. * Note: called even if the corresponding open() failed. * - * Required method. + * Required method. Called with tty lock held. * * void (*shutdown)(struct tty_struct * tty); * @@ -172,6 +172,8 @@ * * Optional: * + * Called with tty lock held. + * * int (*break_ctl)(struct tty_struct *tty, int state); * * This optional routine requests the tty driver to turn on or -- cgit v1.2.3 From 2c964a2f4191f2229566895f1a0e85f8339f5dd1 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Thu, 10 Jul 2014 21:01:22 +0200 Subject: drivers: tty: Merge alloc_tty_struct and initialize_tty_struct The two functions alloc_tty_struct and initialize_tty_struct are always called together. Merge them into alloc_tty_struct, updating its prototype and the only two callers of these functions. Signed-off-by: Rasmus Villemoes Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/tty.h b/include/linux/tty.h index 1c3316a47d7e..84132942902a 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -477,13 +477,11 @@ extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg); extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg); extern void tty_default_fops(struct file_operations *fops); -extern struct tty_struct *alloc_tty_struct(void); +extern struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx); extern int tty_alloc_file(struct file *file); extern void tty_add_file(struct tty_struct *tty, struct file *file); extern void tty_free_file(struct file *file); extern void free_tty_struct(struct tty_struct *tty); -extern void initialize_tty_struct(struct tty_struct *tty, - struct tty_driver *driver, int idx); extern void deinitialize_tty_struct(struct tty_struct *tty); extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx); extern int tty_release(struct inode *inode, struct file *filp); -- cgit v1.2.3 From b1261c86fe238cc0da3f5dc837a38a0c39f3e7c4 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Mon, 14 Jul 2014 14:26:14 +0300 Subject: serial: 8250: introduce up_to_u8250p() helper It helps to cast struct uart_port to struct uart_8250_port at runtime. Signed-off-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_8250.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux') diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index af47a8af6024..730ab4b3d686 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -100,6 +100,11 @@ struct uart_8250_port { void (*dl_write)(struct uart_8250_port *, int); }; +static inline struct uart_8250_port *up_to_u8250p(struct uart_port *up) +{ + return container_of(up, struct uart_8250_port, port); +} + int serial8250_register_8250_port(struct uart_8250_port *); void serial8250_unregister_port(int line); void serial8250_suspend_port(int line); -- cgit v1.2.3 From 266dcff03eed0050b6af11aaf2a61ab837d7ba3f Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 16 Jul 2014 01:19:34 +0000 Subject: Serial: allow port drivers to have a default attribute group Some serial drivers (like 8250), want to add sysfs files. We need to do so in a race-free way, so allow any port to be able to specify an attribute group that should be added at device creation time. Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yoshihiro YUNOMAE Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_core.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 5bbb809ee197..cf3a1e789bf5 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -199,6 +199,8 @@ struct uart_port { unsigned char suspended; unsigned char irq_wake; unsigned char unused[2]; + struct attribute_group *attr_group; /* port specific attributes */ + const struct attribute_group **tty_groups; /* all attributes (serial core use only) */ void *private_data; /* generic platform data pointer */ }; -- cgit v1.2.3 From aef9a7bd9b676f797dd5cefd43deb30d36b976a9 Mon Sep 17 00:00:00 2001 From: Yoshihiro YUNOMAE Date: Wed, 16 Jul 2014 01:19:36 +0000 Subject: serial/uart/8250: Add tunable RX interrupt trigger I/F of FIFO buffers Add tunable RX interrupt trigger I/F of FIFO buffers. Serial devices are used as not only message communication devices but control or sending communication devices. For the latter uses, normally small data will be exchanged, so user applications want to receive data unit as soon as possible for real-time tendency. If we have a sensor which sends a 1 byte data each time and must control a device based on the sensor feedback, the RX interrupt should be triggered for each data. According to HW specification of serial UART devices, RX interrupt trigger can be changed, but the trigger is hard-coded. For example, RX interrupt trigger in 16550A can be set to 1, 4, 8, or 14 bytes for HW, but current driver sets the trigger to only 8bytes. This patch makes some devices change RX interrupt trigger from userland. - Read current setting # cat /sys/class/tty/ttyS0/rx_trig_bytes 8 - Write user setting # echo 1 > /sys/class/tty/ttyS0/rx_trig_bytes # cat /sys/class/tty/ttyS0/rx_trig_bytes 1 - 16550A and Tegra (1, 4, 8, or 14 bytes) - 16650V2 (8, 16, 24, or 28 bytes) - 16654 (8, 16, 56, or 60 bytes) - 16750 (1, 16, 32, or 56 bytes) Changes in V9: - Use attr_group instead of dev_spec_attr_group of uart_port structure Changes in V8: - Divide this patch from V7's patch based on Greg's comment Changes in V7: - Add Documentation - Change I/F name from rx_int_trig to rx_trig_bytes because the name rx_int_trig is hard to understand how users specify the value Changes in V6: - Move FCR_RX_TRIG_* definition in 8250.h to include/uapi/linux/serial_reg.h, rename those to UART_FCR_R_TRIG_*, and use UART_FCR_TRIGGER_MASK to UART_FCR_R_TRIG_BITS() - Change following function names: convert_fcr2val() => fcr_get_rxtrig_bytes() convert_val2rxtrig() => bytes_to_fcr_rxtrig() - Fix typo in serial8250_do_set_termios() - Delete the verbose error message pr_info() in bytes_to_fcr_rxtrig() - Rename *rx_int_trig/rx_trig* to *rxtrig* for several functions or variables (but UI remains rx_int_trig) - Change the meaningless variable name 'val' to 'bytes' following functions: fcr_get_rxtrig_bytes(), bytes_to_fcr_rxtrig(), do_set_rxtrig(), do_serial8250_set_rxtrig(), and serial8250_set_attr_rxtrig() - Use up->fcr in order to get rxtrig_bytes instead of rx_trig_raw in fcr_get_rxtrig_bytes() - Use conf_type->rxtrig_bytes[0] instead of switch statement for support check in register_dev_spec_attr_grp() - Delete the checking whether a user changed FCR or not when minimum buffer is needed in serial8250_do_set_termios() Changes in V5.1: - Fix FCR_RX_TRIG_MAX_STATE definition Changes in V5: - Support Tegra, 16650V2, 16654, and 16750 - Store default FCR value to up->fcr when the port is first created - Add rx_trig_byte[] in uart_config[] for each device and use rx_trig_byte[] in convert_fcr2val() and convert_val2rxtrig() Changes in V4: - Introduce fifo_bug flag in uart_8250_port structure This is enabled only when parity is enabled and UART_BUG_PARITY is enabled for up->bugs. If this flag is enabled, user cannot set RX trigger. - Return -EOPNOTSUPP when it does not support device at convert_fcr2val() and at convert_val2rxtrig() - Set the nearest lower RX trigger when users input a meaningless value at convert_val2rxtrig() - Check whether p->fcr is existing at serial8250_clear_and_reinit_fifos() - Set fcr = up->fcr in the begging of serial8250_do_set_termios() Changes in V3: - Change I/F from ioctl(2) to sysfs(rx_int_trig) Changed in V2: - Use _IOW for TIOCSFIFORTRIG definition - Pass the interrupt trigger value itself Signed-off-by: Yoshihiro YUNOMAE Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_8250.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') 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; -- cgit v1.2.3