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TTY/Serial driver fixes for 5.8-rc6

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Here are some small tty and serial driver fixes for 5.8-rc6.
 
 The largest set of patches in here is a revert of the sysrq changes that
 went into 5.8-rc1 but turned out to cause a noticable overhead and cpu
 usage.
 
 Other than that, there's a few small serial driver fixes to resolve
 reported issues, and finally resolving the spinlock init problem on many
 serial driver consoles.
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-5.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty into master

Pull tty/serial driver fixes from Greg KH:
 :Here are some small tty and serial driver fixes for 5.8-rc6.

  The largest set of patches in here is a revert of the sysrq changes
  that went into 5.8-rc1 but turned out to cause a noticable overhead
  and cpu usage.

  Other than that, there's a few small serial driver fixes to resolve
  reported issues, and finally resolving the spinlock init problem on
  many serial driver consoles.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: core: Initialise spin lock before use in uart_configure_port()
  serial: mxs-auart: add missed iounmap() in probe failure and remove
  serial: sh-sci: Initialize spinlock for uart console
  Revert "tty: xilinx_uartps: Fix missing id assignment to the console"
  serial: core: drop redundant sysrq checks
  serial: core: fix sysrq overhead regression
  Revert "serial: core: Refactor uart_unlock_and_check_sysrq()"
  tty/serial: fix serial_core.c kernel-doc warnings
  tty: serial: cpm_uart: Fix behaviour for non existing GPIOs
This commit is contained in:
Linus Torvalds 2020-07-16 11:10:27 -07:00
commit 7531ee3147
6 changed files with 134 additions and 108 deletions
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102
include/linux/serial_core.h
View file

@ -462,10 +462,104 @@ extern void uart_handle_cts_change(struct uart_port *uport,
extern void uart_insert_char(struct uart_port *port, unsigned int status,
unsigned int overrun, unsigned int ch, unsigned int flag);
extern int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch);
extern int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch);
extern void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long flags);
extern int uart_handle_break(struct uart_port *port);
#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
#define SYSRQ_TIMEOUT (HZ * 5)
bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch);
static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
{
if (!port->sysrq)
return 0;
if (ch && time_before(jiffies, port->sysrq)) {
if (sysrq_mask()) {
handle_sysrq(ch);
port->sysrq = 0;
return 1;
}
if (uart_try_toggle_sysrq(port, ch))
return 1;
}
port->sysrq = 0;
return 0;
}
static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
{
if (!port->sysrq)
return 0;
if (ch && time_before(jiffies, port->sysrq)) {
if (sysrq_mask()) {
port->sysrq_ch = ch;
port->sysrq = 0;
return 1;
}
if (uart_try_toggle_sysrq(port, ch))
return 1;
}
port->sysrq = 0;
return 0;
}
static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
{
int sysrq_ch;
if (!port->has_sysrq) {
spin_unlock_irqrestore(&port->lock, irqflags);
return;
}
sysrq_ch = port->sysrq_ch;
port->sysrq_ch = 0;
spin_unlock_irqrestore(&port->lock, irqflags);
if (sysrq_ch)
handle_sysrq(sysrq_ch);
}
#else /* CONFIG_MAGIC_SYSRQ_SERIAL */
static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
{
return 0;
}
static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
{
return 0;
}
static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
{
spin_unlock_irqrestore(&port->lock, irqflags);
}
#endif /* CONFIG_MAGIC_SYSRQ_SERIAL */
/*
* We do the SysRQ and SAK checking like this...
*/
static inline int uart_handle_break(struct uart_port *port)
{
struct uart_state *state = port->state;
if (port->handle_break)
port->handle_break(port);
#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
if (port->has_sysrq && uart_console(port)) {
if (!port->sysrq) {
port->sysrq = jiffies + SYSRQ_TIMEOUT;
return 1;
}
port->sysrq = 0;
}
#endif
if (port->flags & UPF_SAK)
do_SAK(state->port.tty);
return 0;
}
/*
* UART_ENABLE_MS - determine if port should enable modem status irqs