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Revert "tty: serial: Use fifo in 8250 console driver"
This reverts commit5021d709b3
. The patch is still a bit buggy, and this breaks some other hardware types. It needs to be resubmitted in a non-buggy way, and make sure the other hardware types also continue to work properly. Fixes:5021d709b3
("tty: serial: Use fifo in 8250 console driver") Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reported-by: Jon Hunter <jonathanh@nvidia.com> Link: https://lore.kernel.org/r/Ye/1+Z8mEzbKbrqG@linutronix.de Link: https://lore.kernel.org/r/a1ac6254-f79e-d131-fa2a-c7ad714c6d4a@nvidia.com Cc: Wander Lairson Costa <wander@redhat.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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1 changed files with 6 additions and 55 deletions
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@ -2056,7 +2056,10 @@ static void serial8250_break_ctl(struct uart_port *port, int break_state)
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serial8250_rpm_put(up);
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}
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static void wait_for_lsr(struct uart_8250_port *up, int bits)
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/*
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* Wait for transmitter & holding register to empty
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*/
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static void wait_for_xmitr(struct uart_8250_port *up, int bits)
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{
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unsigned int status, tmout = 10000;
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@ -2073,16 +2076,6 @@ static void wait_for_lsr(struct uart_8250_port *up, int bits)
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udelay(1);
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touch_nmi_watchdog();
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}
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}
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/*
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* Wait for transmitter & holding register to empty
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*/
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static void wait_for_xmitr(struct uart_8250_port *up, int bits)
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{
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unsigned int tmout;
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wait_for_lsr(up, bits);
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/* Wait up to 1s for flow control if necessary */
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if (up->port.flags & UPF_CONS_FLOW) {
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@ -3332,35 +3325,6 @@ static void serial8250_console_restore(struct uart_8250_port *up)
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serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS);
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}
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/*
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* Print a string to the serial port using the device FIFO
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*
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* It sends fifosize bytes and then waits for the fifo
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* to get empty.
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*/
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static void serial8250_console_fifo_write(struct uart_8250_port *up,
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const char *s, unsigned int count)
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{
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int i;
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const char *end = s + count;
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unsigned int fifosize = up->port.fifosize;
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bool cr_sent = false;
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while (s != end) {
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wait_for_lsr(up, UART_LSR_THRE);
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for (i = 0; i < fifosize && s != end; ++i) {
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if (*s == '\n' && !cr_sent) {
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serial_out(up, UART_TX, '\r');
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cr_sent = true;
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} else {
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serial_out(up, UART_TX, *s++);
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cr_sent = false;
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}
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}
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}
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}
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/*
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* Print a string to the serial port trying not to disturb
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* any possible real use of the port...
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@ -3376,7 +3340,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
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struct uart_8250_em485 *em485 = up->em485;
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struct uart_port *port = &up->port;
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unsigned long flags;
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unsigned int ier, use_fifo;
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unsigned int ier;
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int locked = 1;
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touch_nmi_watchdog();
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@ -3408,20 +3372,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
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mdelay(port->rs485.delay_rts_before_send);
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}
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use_fifo = (up->capabilities & UART_CAP_FIFO) &&
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port->fifosize > 1 &&
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(serial_port_in(port, UART_FCR) & UART_FCR_ENABLE_FIFO) &&
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/*
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* After we put a data in the fifo, the controller will send
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* it regardless of the CTS state. Therefore, only use fifo
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* if we don't use control flow.
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*/
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!(up->port.flags & UPF_CONS_FLOW);
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if (likely(use_fifo))
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serial8250_console_fifo_write(up, s, count);
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else
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uart_console_write(port, s, count, serial8250_console_putchar);
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uart_console_write(port, s, count, serial8250_console_putchar);
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/*
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* Finally, wait for transmitter to become empty
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