pm24.git/include/linux/serial_core.h, branch v4.0-rc2

serial: core: Rework hw-assisted flow control support

2015-02-02T18:11:28Z

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

serial: omap_8250: Fix RTS handling

2015-01-09T22:10:46Z

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

serial: core: Add big-endian iotype

2014-11-26T01:06:40Z

Since most drivers interpret UPIO_MEM32 to mean "little-endian" and use readl/writel to access the registers, add a parallel UPIO_MEM32BE to request the use of big-endian MMIO accessors (ioread32be/iowrite32be). Signed-off-by: Kevin Cernekee Signed-off-by: Greg Kroah-Hartman

serial_core: Handle TIOC[GS]RS485 ioctls.

2014-11-06T22:58:53Z

The following drivers: 8250_core, atmel_serial, max310x, mcf, omap-serial and sci16is7xx implement code to handle RS485 ioctls. In order to avoid code duplication, we implement a simple ioctl handler on the serial_core layer. This handler can be used by all the other drivers instead of duplicating code. Until this is the only RS485 ioctl handler, it will try first the rs485_config callback and if it is not present it will call the driver specific ioctl. Reviewed-by: Alan Cox Cc: Greg Kroah-Hartman Cc: Jiri Slaby Signed-off-by: Ricardo Ribalda Delgado Signed-off-by: Greg Kroah-Hartman

serial: core: Pass termios to set_ldisc() notifications

2014-11-06T22:57:27Z

UART drivers which enable modem status interrupts when switching to N_PPS line discipline need to determine if modem status interrupts should be disabled when switching from N_PPS. Specifically, the set_ldisc() notification needs to evaluate UART_ENABLE_MS() which requires termios->c_cflag. Convert in-tree UART drivers to new interface. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty,serial: Unify UPF_* and ASYNC_* flag definitions

2014-11-06T02:53:54Z

The userspace-defined ASYNC_* flags in include/uapi/linux/tty_flags.h are the authoritative bit definitions for the serial_struct flags, and thus for any derivative values or fields. Although the serial core provides the TIOCSSERIAL and TIOCGSERIAL ioctls to set and retrieve these flags from userspace, it defines these bits independently, as UPF_* macros. Define the UPF_* macros which are userspace-modifiable directly from the ASYNC_* symbolic constants. Add compile-time test to ensure the bits changeable by TIOCSSERIAL match the defined range in the uapi header. Add ASYNCB_MAGIC_MULTIPLIER to the uapi header since this bit is programmable by userspace. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

serial: Fix upstat_t sparse warnings

2014-11-06T00:15:43Z

Commit 299245a145b2ad4cfb4c5432eb1264299f55e7e0, serial: core: Privatize modem status enable flags, introduced the upstat_t type and matching bit definitions. The purpose is to produce sparse warnings if the wrong bit definitions are used (by warning of implicit integer conversions). Fix implicit conversion to integer return type from uart_cts_enabled() and uart_dcd_enabled(). Fixes the following sparse warnings: drivers/tty/serial/serial_core.c:63:30: warning: incorrect type in return expression (different base types) drivers/tty/serial/serial_core.c:63:30: expected int drivers/tty/serial/serial_core.c:63:30: got restricted upstat_t include/linux/serial_core.h:364:30: warning: incorrect type in return expression (different base types) include/linux/serial_core.h:364:30: expected bool include/linux/serial_core.h:364:30: got restricted upstat_t include/linux/serial_core.h:364:30: warning: incorrect type in return expression (different base types) include/linux/serial_core.h:364:30: expected bool include/linux/serial_core.h:364:30: got restricted upstat_t Reported-by: Fengguang Wu Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: serial: 8250_core: allow to set ->throttle / ->unthrottle callbacks

2014-09-26T16:01:56Z

The OMAP UART provides support for HW assisted flow control. What is missing is the support to throttle / unthrottle callbacks which are used by the omap-serial driver at the moment. This patch adds the callbacks. It should be safe to add them since they are only invoked from the serial_core (uart_throttle()) if the feature flags are set. Reviewed-by: Tony Lindgren Tested-by: Tony Lindgren Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Greg Kroah-Hartman

serial: core: Privatize tty->hw_stopped

2014-09-24T04:19:35Z

tty->hw_stopped is not used by the tty core and is thread-unsafe; hw_stopped is a member of a bitfield whose fields are updated non-atomically and no lock is suitable for serializing updates. Replace serial core usage of tty->hw_stopped with uport->hw_stopped. Use int storage which works around Alpha EV4/5 non-atomic byte storage, since uart_port uses different locks to protect certain fields within the structure. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

serial: core: Privatize modem status enable flags

2014-09-24T04:19:35Z

The serial core uses the tty port flags, ASYNC_CTS_FLOW and ASYNC_CD_CHECK, to track whether CTS and DCD changes should be ignored or handled. However, the tty port flags are not safe for atomic bit operations and no lock provides serialized updates. Introduce the struct uart_port status field to track CTS and DCD enable states, and serialize access with uart port lock. Substitute uart_cts_enabled() helper for tty_port_cts_enabled(). Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman