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serial: sh-sci: Replace buggy big #ifdef by runtime logic
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The #ifdef logic to clear SCxSR bits using RMW on SCIFA/SCIFB and SCIF
variants with some SCIFA features (sh7705/SH7720/sh7721) has several
drawbacks:
  - It wasn't updated for newer R-Mobile variants (APE6),
  - It doesn't correctly handle SoCs with both SCIF and SCIFA/B (e.g.
    R-Car Gen2, but also legacy sh7723/sh7724),
  - It doesn't play well with ARM multi-platform kernels: on R-Car Gen2,
    SCIF/SCIFA/SCIFB/HSCIF were handled differently, depending on
    whether r8a7740 or sh73a0 support was enabled or not,

Replace the #ifdef logic by runtime logic to fix this.

SCIFA/SCIFB and SCIF on sh7705/sh7720/sh7721 use RMW to clear error
bits, other variants use plain stores, as before.

Note that this changes behavior for SCIFA on sh7723/sh7724 (these SoCs
have both SCIF and SCIFA), which didn't use RMW before.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Geert Uytterhoeven authored and Greg Kroah-Hartman committed Oct 4, 2015
1 parent 9a23a1d commit a1b5b43
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Showing 2 changed files with 34 additions and 35 deletions.
36 changes: 26 additions & 10 deletions drivers/tty/serial/sh-sci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -489,6 +489,22 @@ static void sci_port_disable(struct sci_port *sci_port)
pm_runtime_put_sync(sci_port->port.dev);
}

static void sci_clear_SCxSR(struct uart_port *port, unsigned int mask)
{
if (port->type == PORT_SCI) {
/* Just store the mask */
serial_port_out(port, SCxSR, mask);
} else if (to_sci_port(port)->overrun_mask == SCIFA_ORER) {
/* SCIFA/SCIFB and SCIF on SH7705/SH7720/SH7721 */
/* Only clear the status bits we want to clear */
serial_port_out(port, SCxSR,
serial_port_in(port, SCxSR) & mask);
} else {
/* Store the mask, clear parity/framing errors */
serial_port_out(port, SCxSR, mask & ~(SCIF_FERC | SCIF_PERC));
}
}

#if defined(CONFIG_CONSOLE_POLL) || defined(CONFIG_SERIAL_SH_SCI_CONSOLE)

#ifdef CONFIG_CONSOLE_POLL
Expand All @@ -500,7 +516,7 @@ static int sci_poll_get_char(struct uart_port *port)
do {
status = serial_port_in(port, SCxSR);
if (status & SCxSR_ERRORS(port)) {
serial_port_out(port, SCxSR, SCxSR_ERROR_CLEAR(port));
sci_clear_SCxSR(port, SCxSR_ERROR_CLEAR(port));
continue;
}
break;
Expand All @@ -513,7 +529,7 @@ static int sci_poll_get_char(struct uart_port *port)

/* Dummy read */
serial_port_in(port, SCxSR);
serial_port_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));
sci_clear_SCxSR(port, SCxSR_RDxF_CLEAR(port));

return c;
}
Expand All @@ -528,7 +544,7 @@ static void sci_poll_put_char(struct uart_port *port, unsigned char c)
} while (!(status & SCxSR_TDxE(port)));

serial_port_out(port, SCxTDR, c);
serial_port_out(port, SCxSR, SCxSR_TDxE_CLEAR(port) & ~SCxSR_TEND(port));
sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port) & ~SCxSR_TEND(port));
}
#endif /* CONFIG_CONSOLE_POLL || CONFIG_SERIAL_SH_SCI_CONSOLE */

Expand Down Expand Up @@ -655,7 +671,7 @@ static void sci_transmit_chars(struct uart_port *port)
port->icount.tx++;
} while (--count > 0);

serial_port_out(port, SCxSR, SCxSR_TDxE_CLEAR(port));
sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port));

if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
Expand All @@ -666,7 +682,7 @@ static void sci_transmit_chars(struct uart_port *port)

if (port->type != PORT_SCI) {
serial_port_in(port, SCxSR); /* Dummy read */
serial_port_out(port, SCxSR, SCxSR_TDxE_CLEAR(port));
sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port));
}

ctrl |= SCSCR_TIE;
Expand Down Expand Up @@ -750,7 +766,7 @@ static void sci_receive_chars(struct uart_port *port)
}

serial_port_in(port, SCxSR); /* dummy read */
serial_port_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));
sci_clear_SCxSR(port, SCxSR_RDxF_CLEAR(port));

copied += count;
port->icount.rx += count;
Expand All @@ -761,7 +777,7 @@ static void sci_receive_chars(struct uart_port *port)
tty_flip_buffer_push(tport);
} else {
serial_port_in(port, SCxSR); /* dummy read */
serial_port_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));
sci_clear_SCxSR(port, SCxSR_RDxF_CLEAR(port));
}
}

Expand Down Expand Up @@ -982,14 +998,14 @@ static irqreturn_t sci_er_interrupt(int irq, void *ptr)
if (sci_handle_errors(port)) {
/* discard character in rx buffer */
serial_port_in(port, SCxSR);
serial_port_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));
sci_clear_SCxSR(port, SCxSR_RDxF_CLEAR(port));
}
} else {
sci_handle_fifo_overrun(port);
sci_rx_interrupt(irq, ptr);
}

serial_port_out(port, SCxSR, SCxSR_ERROR_CLEAR(port));
sci_clear_SCxSR(port, SCxSR_ERROR_CLEAR(port));

/* Kick the transmission */
sci_tx_interrupt(irq, ptr);
Expand All @@ -1003,7 +1019,7 @@ static irqreturn_t sci_br_interrupt(int irq, void *ptr)

/* Handle BREAKs */
sci_handle_breaks(port);
serial_port_out(port, SCxSR, SCxSR_BREAK_CLEAR(port));
sci_clear_SCxSR(port, SCxSR_BREAK_CLEAR(port));

return IRQ_HANDLED;
}
Expand Down
33 changes: 8 additions & 25 deletions drivers/tty/serial/sh-sci.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -119,28 +119,11 @@ enum {

#define SCxSR_ERRORS(port) (to_sci_port(port)->error_mask)

#if defined(CONFIG_CPU_SUBTYPE_SH7705) || \
defined(CONFIG_CPU_SUBTYPE_SH7720) || \
defined(CONFIG_CPU_SUBTYPE_SH7721) || \
defined(CONFIG_ARCH_SH73A0) || \
defined(CONFIG_ARCH_R8A7740)

# define SCxSR_RDxF_CLEAR(port) \
(serial_port_in(port, SCxSR) & SCIF_RDxF_CLEAR)
# define SCxSR_ERROR_CLEAR(port) \
(serial_port_in(port, SCxSR) & SCIF_ERROR_CLEAR)
# define SCxSR_TDxE_CLEAR(port) \
(serial_port_in(port, SCxSR) & SCIF_TDxE_CLEAR)
# define SCxSR_BREAK_CLEAR(port) \
(serial_port_in(port, SCxSR) & SCIF_BREAK_CLEAR)
#else
# define SCxSR_RDxF_CLEAR(port) \
((((port)->type == PORT_SCI) ? SCI_RDxF_CLEAR : SCIF_RDxF_CLEAR) & 0xff)
# define SCxSR_ERROR_CLEAR(port) \
((((port)->type == PORT_SCI) ? SCI_ERROR_CLEAR : SCIF_ERROR_CLEAR) & 0xff)
# define SCxSR_TDxE_CLEAR(port) \
((((port)->type == PORT_SCI) ? SCI_TDxE_CLEAR : SCIF_TDxE_CLEAR) & 0xff)
# define SCxSR_BREAK_CLEAR(port) \
((((port)->type == PORT_SCI) ? SCI_BREAK_CLEAR : SCIF_BREAK_CLEAR) & 0xff)
#endif

#define SCxSR_RDxF_CLEAR(port) \
(((port)->type == PORT_SCI) ? SCI_RDxF_CLEAR : SCIF_RDxF_CLEAR)
#define SCxSR_ERROR_CLEAR(port) \
(((port)->type == PORT_SCI) ? SCI_ERROR_CLEAR : SCIF_ERROR_CLEAR)
#define SCxSR_TDxE_CLEAR(port) \
(((port)->type == PORT_SCI) ? SCI_TDxE_CLEAR : SCIF_TDxE_CLEAR)
#define SCxSR_BREAK_CLEAR(port) \
(((port)->type == PORT_SCI) ? SCI_BREAK_CLEAR : SCIF_BREAK_CLEAR)

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