[PATCH v2 0/7] Renesas *SCIF* RX FIFO support

[PATCH v2 0/7] Renesas *SCIF* RX FIFO support

[Ulrich Hecht]

Hi!

This series implements support for using RX FIFO thresholds higher than one
in PIO mode on SCIF, HSCIF, SCIFA and SCIFB serial ports.

This revision addresses the issues found by Geert and Sergei in their
reviews, see below for details.

Setting the RX trigger on SH77xx-style ports is still not handled correctly,
mostly because we don't have any hardware to test against. I have changed
the trigger default for these ports to 1 to avoid regressions.

CU
Uli


Changes since v1:
- clarify HS trigger register enum
- simplify DR bit handling
- if() cascade -> switch()
- disable RX trigger for SH77xx-style ports
- clean up on failure to create sysfs attribute
- r8a7796 DT: add control pins, rtscts flag


Ulrich Hecht (7):
  serial: sh-sci: add FIFO trigger bits
  serial: sh-sci: consider DR (data ready) bit adequately
  serial: sh-sci: implement FIFO threshold register setting
  serial: sh-sci: increase RX FIFO trigger defaults for (H)SCIF
  serial: sh-sci: SCIFA/B RX FIFO software timeout
  serial: sh-sci: make RX FIFO parameters tunable via sysfs
  arm64: dts: r8a7796: salvator-x: add SCIF1 (DEBUG1)

 arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts |  14 ++
 drivers/tty/serial/sh-sci.c                        | 259 ++++++++++++++++++---
 drivers/tty/serial/sh-sci.h                        |   8 +-
 3 files changed, 248 insertions(+), 33 deletions(-)

-- 
2.7.4

[PATCH v2 1/7] serial: sh-sci: add FIFO trigger bits

[Ulrich Hecht]

Defines the bits controlling FIFO thresholds, adds the additional
HSCIF registers to the register map.

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/tty/serial/sh-sci.c | 2 ++
 drivers/tty/serial/sh-sci.h | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index db5de80..3a9c001 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -377,6 +377,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[SCPDR]		= sci_reg_invalid,
 		[SCDL]		= { 0x30, 16 },
 		[SCCKS]		= { 0x34, 16 },
+		[HSRTRGR]	= { 0x54, 16 },
+		[HSTTRGR]	= { 0x58, 16 },
 	},
 
 	/*
diff --git a/drivers/tty/serial/sh-sci.h b/drivers/tty/serial/sh-sci.h
index ffa6d68..2c45e79 100644
--- a/drivers/tty/serial/sh-sci.h
+++ b/drivers/tty/serial/sh-sci.h
@@ -29,6 +29,8 @@ enum {
 	SCPDR,				/* Serial Port Data Register */
 	SCDL,				/* BRG Frequency Division Register */
 	SCCKS,				/* BRG Clock Select Register */
+	HSRTRGR,			/* Rx FIFO Data Count Trigger Register */
+	HSTTRGR,			/* Tx FIFO Data Count Trigger Register */
 
 	SCIx_NR_REGS,
 };
@@ -99,6 +101,10 @@ enum {
 #define SCIF_BREAK_CLEAR	(u32)(~(SCIF_PER | SCIF_FER | SCIF_BRK))
 
 /* SCFCR (FIFO Control Register) */
+#define SCFCR_RTRG1	BIT(7)	/* Receive FIFO Data Count Trigger */
+#define SCFCR_RTRG0	BIT(6)
+#define SCFCR_TTRG1	BIT(5)	/* Transmit FIFO Data Count Trigger */
+#define SCFCR_TTRG0	BIT(4)
 #define SCFCR_MCE	BIT(3)	/* Modem Control Enable */
 #define SCFCR_TFRST	BIT(2)	/* Transmit FIFO Data Register Reset */
 #define SCFCR_RFRST	BIT(1)	/* Receive FIFO Data Register Reset */
-- 
2.7.4

[PATCH v2 2/7] serial: sh-sci: consider DR (data ready) bit adequately

[Ulrich Hecht]

To allow operation with a higher RX FIFO interrupt threshold in PIO
mode, it is necessary to consider the DR bit ("FIFO not full, but no
data received for 1.5 frames") as an indicator that data can be read.
Otherwise the driver will let data rot in the FIFO until the threshold
is reached.

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
---
 drivers/tty/serial/sh-sci.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/sh-sci.h b/drivers/tty/serial/sh-sci.h
index 2c45e79..9323735 100644
--- a/drivers/tty/serial/sh-sci.h
+++ b/drivers/tty/serial/sh-sci.h
@@ -151,7 +151,7 @@ enum {
 #define SCCKS_XIN	BIT(14)	/* SC_CLK uses bus clock (1) or SCIF_CLK (0) */
 
 #define SCxSR_TEND(port)	(((port)->type == PORT_SCI) ? SCI_TEND   : SCIF_TEND)
-#define SCxSR_RDxF(port)	(((port)->type == PORT_SCI) ? SCI_RDRF   : SCIF_RDF)
+#define SCxSR_RDxF(port)	(((port)->type == PORT_SCI) ? SCI_RDRF   : SCIF_DR | SCIF_RDF)
 #define SCxSR_TDxE(port)	(((port)->type == PORT_SCI) ? SCI_TDRE   : SCIF_TDFE)
 #define SCxSR_FER(port)		(((port)->type == PORT_SCI) ? SCI_FER    : SCIF_FER)
 #define SCxSR_PER(port)		(((port)->type == PORT_SCI) ? SCI_PER    : SCIF_PER)
-- 
2.7.4

Re: [PATCH v2 2/7] serial: sh-sci: consider DR (data ready) bit adequately

[Geert Uytterhoeven]

On Mon, Jan 23, 2017 at 5:04 PM, Ulrich Hecht
<ulrich.hecht+renesas@gmail.com> wrote:
> To allow operation with a higher RX FIFO interrupt threshold in PIO
> mode, it is necessary to consider the DR bit ("FIFO not full, but no
> data received for 1.5 frames") as an indicator that data can be read.
> Otherwise the driver will let data rot in the FIFO until the threshold
> is reached.
>
> Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2 3/7] serial: sh-sci: implement FIFO threshold register setting

[Ulrich Hecht]

Sets the closest match for a desired RX trigger level.

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/tty/serial/sh-sci.c | 59 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 3a9c001..39734cc 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1102,6 +1102,65 @@ static int sci_handle_breaks(struct uart_port *port)
 	return copied;
 }
 
+static int scif_set_rtrg(struct uart_port *port, int rx_trig)
+{
+	unsigned int bits;
+
+	if (rx_trig < 1)
+		rx_trig = 1;
+	if (rx_trig >= port->fifosize)
+		rx_trig = port->fifosize;
+
+	/* HSCIF can be set to an arbitrary level. */
+	if (sci_getreg(port, HSRTRGR)->size) {
+		serial_port_out(port, HSRTRGR, rx_trig);
+		return rx_trig;
+	}
+
+	switch (port->type) {
+	case PORT_SCIF:
+		if (rx_trig < 4) {
+			bits = 0;
+			rx_trig = 1;
+		} else if (rx_trig < 8) {
+			bits = SCFCR_RTRG0;
+			rx_trig = 4;
+		} else if (rx_trig < 14) {
+			bits = SCFCR_RTRG1;
+			rx_trig = 8;
+		} else {
+			bits = SCFCR_RTRG0 | SCFCR_RTRG1;
+			rx_trig = 14;
+		}
+		break;
+	case PORT_SCIFA:
+	case PORT_SCIFB:
+		if (rx_trig < 16) {
+			bits = 0;
+			rx_trig = 1;
+		} else if (rx_trig < 32) {
+			bits = SCFCR_RTRG0;
+			rx_trig = 16;
+		} else if (rx_trig < 48) {
+			bits = SCFCR_RTRG1;
+			rx_trig = 32;
+		} else {
+			bits = SCFCR_RTRG0 | SCFCR_RTRG1;
+			rx_trig = 48;
+		}
+		break;
+	default:
+		WARN(1, "unknown FIFO configuration");
+		return 1;
+	}
+
+	serial_port_out(port, SCFCR,
+		(serial_port_in(port, SCFCR) &
+		~(SCFCR_RTRG1 | SCFCR_RTRG0)) | bits);
+
+	return rx_trig;
+}
+
 #ifdef CONFIG_SERIAL_SH_SCI_DMA
 static void sci_dma_tx_complete(void *arg)
 {
-- 
2.7.4

[PATCH v2 4/7] serial: sh-sci: increase RX FIFO trigger defaults for (H)SCIF

[Ulrich Hecht]

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
---
 drivers/tty/serial/sh-sci.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 39734cc..c7e2d0d 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -141,6 +141,7 @@ struct sci_port {
 	struct timer_list		rx_timer;
 	unsigned int			rx_timeout;
 #endif
+	int				rx_trigger;
 
 	bool autorts;
 };
@@ -2197,6 +2198,7 @@ static void sci_reset(struct uart_port *port)
 {
 	const struct plat_sci_reg *reg;
 	unsigned int status;
+	struct sci_port *s = to_sci_port(port);
 
 	if (serial_port_in(port, SCSCR) & SCSCR_TE) {
 		do {
@@ -2218,6 +2220,9 @@ static void sci_reset(struct uart_port *port)
 		status &= ~(SCLSR_TO | SCLSR_ORER);
 		serial_port_out(port, SCLSR, status);
 	}
+
+	if (s->rx_trigger > 1)
+		scif_set_rtrg(port, s->rx_trigger);
 }
 
 static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
@@ -2728,6 +2733,7 @@ static int sci_init_single(struct platform_device *dev,
 		sci_port->overrun_reg = SCLSR;
 		sci_port->overrun_mask = SCLSR_ORER;
 		sci_port->sampling_rate_mask = SCI_SR_RANGE(8, 32);
+		sci_port->rx_trigger = 64;
 		break;
 	case PORT_SCIFA:
 		port->fifosize = 64;
@@ -2736,15 +2742,19 @@ static int sci_init_single(struct platform_device *dev,
 		sci_port->sampling_rate_mask = SCI_SR_SCIFAB;
 		break;
 	case PORT_SCIF:
-		port->fifosize = 16;
 		if (p->regtype == SCIx_SH7705_SCIF_REGTYPE) {
+			port->fifosize = 64;
 			sci_port->overrun_reg = SCxSR;
 			sci_port->overrun_mask = SCIFA_ORER;
 			sci_port->sampling_rate_mask = SCI_SR(16);
+			/* RX triggering not implemented for this IP */
+			sci_port->rx_trigger = 1;
 		} else {
+			port->fifosize = 16;
 			sci_port->overrun_reg = SCLSR;
 			sci_port->overrun_mask = SCLSR_ORER;
 			sci_port->sampling_rate_mask = SCI_SR(32);
+			sci_port->rx_trigger = 8;
 		}
 		break;
 	default:
@@ -2752,6 +2762,7 @@ static int sci_init_single(struct platform_device *dev,
 		sci_port->overrun_reg = SCxSR;
 		sci_port->overrun_mask = SCI_ORER;
 		sci_port->sampling_rate_mask = SCI_SR(32);
+		sci_port->rx_trigger = 1;
 		break;
 	}
 
-- 
2.7.4

Re: [PATCH v2 4/7] serial: sh-sci: increase RX FIFO trigger defaults for (H)SCIF

[Geert Uytterhoeven]

On Mon, Jan 23, 2017 at 5:04 PM, Ulrich Hecht
<ulrich.hecht+renesas@gmail.com> wrote:
> Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

> @@ -2736,15 +2742,19 @@ static int sci_init_single(struct platform_device *dev,
>                 sci_port->sampling_rate_mask = SCI_SR_SCIFAB;
>                 break;
>         case PORT_SCIF:
> -               port->fifosize = 16;
>                 if (p->regtype == SCIx_SH7705_SCIF_REGTYPE) {
> +                       port->fifosize = 64;

Note that you forgot to mention that you also corrected the FIFO size for
sh7705, ssh7720, and sh7721. Not that we can easily test that, though.

>                         sci_port->overrun_reg = SCxSR;
>                         sci_port->overrun_mask = SCIFA_ORER;
>                         sci_port->sampling_rate_mask = SCI_SR(16);
> +                       /* RX triggering not implemented for this IP */
> +                       sci_port->rx_trigger = 1;
>                 } else {
> +                       port->fifosize = 16;
>                         sci_port->overrun_reg = SCLSR;
>                         sci_port->overrun_mask = SCLSR_ORER;
>                         sci_port->sampling_rate_mask = SCI_SR(32);
> +                       sci_port->rx_trigger = 8;
>                 }
>                 break;
>         default:




-- 
Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2 4/7] serial: sh-sci: increase RX FIFO trigger defaults for (H)SCIF

[Greg KH]

On Mon, Jan 23, 2017 at 05:04:15PM +0100, Ulrich Hecht wrote:
> Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
> ---
>  drivers/tty/serial/sh-sci.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)

I will not take a patch without any changelog text, sorry...

[PATCH v2 5/7] serial: sh-sci: SCIFA/B RX FIFO software timeout

[Ulrich Hecht]

Implements support for FIFO fill thresholds greater than one with software
timeout.

This mechanism is not possible (or at least not useful) on SCIF family
hardware other than SCIFA and SCIFB because they do not support turning off
the DR hardware timeout interrupt separately from the RI interrupt.

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
---
 drivers/tty/serial/sh-sci.c | 102 ++++++++++++++++++++++++++++++--------------
 1 file changed, 69 insertions(+), 33 deletions(-)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index c7e2d0d..034041e 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -141,7 +141,10 @@ struct sci_port {
 	struct timer_list		rx_timer;
 	unsigned int			rx_timeout;
 #endif
+	unsigned int			rx_frame;
 	int				rx_trigger;
+	struct timer_list		rx_fifo_timer;
+	int				rx_fifo_timeout;
 
 	bool autorts;
 };
@@ -1162,6 +1165,24 @@ static int scif_set_rtrg(struct uart_port *port, int rx_trig)
 	return rx_trig;
 }
 
+static int scif_rtrg_enabled(struct uart_port *port)
+{
+	if (sci_getreg(port, HSRTRGR)->size)
+		return serial_port_in(port, HSRTRGR) != 0;
+	else
+		return (serial_port_in(port, SCFCR) &
+			(SCFCR_RTRG0 | SCFCR_RTRG1)) != 0;
+}
+
+static void rx_fifo_timer_fn(unsigned long arg)
+{
+	struct sci_port *s = (struct sci_port *)arg;
+	struct uart_port *port = &s->port;
+
+	dev_dbg(port->dev, "Rx timed out\n");
+	scif_set_rtrg(port, 1);
+}
+
 #ifdef CONFIG_SERIAL_SH_SCI_DMA
 static void sci_dma_tx_complete(void *arg)
 {
@@ -1608,9 +1629,9 @@ static inline void sci_free_dma(struct uart_port *port)
 
 static irqreturn_t sci_rx_interrupt(int irq, void *ptr)
 {
-#ifdef CONFIG_SERIAL_SH_SCI_DMA
 	struct uart_port *port = ptr;
 	struct sci_port *s = to_sci_port(port);
+#ifdef CONFIG_SERIAL_SH_SCI_DMA
 
 	if (s->chan_rx) {
 		u16 scr = serial_port_in(port, SCSCR);
@@ -1636,6 +1657,14 @@ static irqreturn_t sci_rx_interrupt(int irq, void *ptr)
 	}
 #endif
 
+	if (s->rx_trigger > 1 && s->rx_fifo_timeout > 0) {
+		if (!scif_rtrg_enabled(port))
+			scif_set_rtrg(port, s->rx_trigger);
+
+		mod_timer(&s->rx_fifo_timer, jiffies + DIV_ROUND_UP(
+			  s->rx_frame * s->rx_fifo_timeout, 1000));
+	}
+
 	/* I think sci_receive_chars has to be called irrespective
 	 * of whether the I_IXOFF is set, otherwise, how is the interrupt
 	 * to be disabled?
@@ -2221,14 +2250,20 @@ static void sci_reset(struct uart_port *port)
 		serial_port_out(port, SCLSR, status);
 	}
 
-	if (s->rx_trigger > 1)
-		scif_set_rtrg(port, s->rx_trigger);
+	if (s->rx_trigger > 1) {
+		if (s->rx_fifo_timeout) {
+			scif_set_rtrg(port, 1);
+			setup_timer(&s->rx_fifo_timer, rx_fifo_timer_fn,
+				    (unsigned long)s);
+		} else
+			scif_set_rtrg(port, s->rx_trigger);
+	}
 }
 
 static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
 			    struct ktermios *old)
 {
-	unsigned int baud, smr_val = SCSMR_ASYNC, scr_val = 0, i;
+	unsigned int baud, smr_val = SCSMR_ASYNC, scr_val = 0, i, bits;
 	unsigned int brr = 255, cks = 0, srr = 15, dl = 0, sccks = 0;
 	unsigned int brr1 = 255, cks1 = 0, srr1 = 15, dl1 = 0;
 	struct sci_port *s = to_sci_port(port);
@@ -2427,7 +2462,6 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
 		udelay(DIV_ROUND_UP(10 * 1000000, baud));
 	}
 
-#ifdef CONFIG_SERIAL_SH_SCI_DMA
 	/*
 	 * Calculate delay for 2 DMA buffers (4 FIFO).
 	 * See serial_core.c::uart_update_timeout().
@@ -2438,36 +2472,34 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
 	 * value obtained by this formula is too small. Therefore, if the value
 	 * is smaller than 20ms, use 20ms as the timeout value for DMA.
 	 */
-	if (s->chan_rx) {
-		unsigned int bits;
+	/* byte size and parity */
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		bits = 7;
+		break;
+	case CS6:
+		bits = 8;
+		break;
+	case CS7:
+		bits = 9;
+		break;
+	default:
+		bits = 10;
+		break;
+	}
 
-		/* byte size and parity */
-		switch (termios->c_cflag & CSIZE) {
-		case CS5:
-			bits = 7;
-			break;
-		case CS6:
-			bits = 8;
-			break;
-		case CS7:
-			bits = 9;
-			break;
-		default:
-			bits = 10;
-			break;
-		}
+	if (termios->c_cflag & CSTOPB)
+		bits++;
+	if (termios->c_cflag & PARENB)
+		bits++;
 
-		if (termios->c_cflag & CSTOPB)
-			bits++;
-		if (termios->c_cflag & PARENB)
-			bits++;
-		s->rx_timeout = DIV_ROUND_UP((s->buf_len_rx * 2 * bits * HZ) /
-					     (baud / 10), 10);
-		dev_dbg(port->dev, "DMA Rx t-out %ums, tty t-out %u jiffies\n",
-			s->rx_timeout * 1000 / HZ, port->timeout);
-		if (s->rx_timeout < msecs_to_jiffies(20))
-			s->rx_timeout = msecs_to_jiffies(20);
-	}
+	s->rx_frame = (100 * bits * HZ) / (baud / 10);
+#ifdef CONFIG_SERIAL_SH_SCI_DMA
+	s->rx_timeout = DIV_ROUND_UP(s->buf_len_rx * 2 * s->rx_frame, 1000);
+	dev_dbg(port->dev, "DMA Rx t-out %ums, tty t-out %u jiffies\n",
+		s->rx_timeout * 1000 / HZ, port->timeout);
+	if (s->rx_timeout < msecs_to_jiffies(20))
+		s->rx_timeout = msecs_to_jiffies(20);
 #endif
 
 	if ((termios->c_cflag & CREAD) != 0)
@@ -2727,6 +2759,7 @@ static int sci_init_single(struct platform_device *dev,
 		sci_port->overrun_reg = SCxSR;
 		sci_port->overrun_mask = SCIFA_ORER;
 		sci_port->sampling_rate_mask = SCI_SR_SCIFAB;
+		sci_port->rx_trigger = 48;
 		break;
 	case PORT_HSCIF:
 		port->fifosize = 128;
@@ -2740,6 +2773,7 @@ static int sci_init_single(struct platform_device *dev,
 		sci_port->overrun_reg = SCxSR;
 		sci_port->overrun_mask = SCIFA_ORER;
 		sci_port->sampling_rate_mask = SCI_SR_SCIFAB;
+		sci_port->rx_trigger = 32;
 		break;
 	case PORT_SCIF:
 		if (p->regtype == SCIx_SH7705_SCIF_REGTYPE) {
@@ -2766,6 +2800,8 @@ static int sci_init_single(struct platform_device *dev,
 		break;
 	}
 
+	sci_port->rx_fifo_timeout = 0;
+
 	/* SCIFA on sh7723 and sh7724 need a custom sampling rate that doesn't
 	 * match the SoC datasheet, this should be investigated. Let platform
 	 * data override the sampling rate for now.
-- 
2.7.4

[PATCH v2 6/7] serial: sh-sci: make RX FIFO parameters tunable via sysfs

[Ulrich Hecht]

Allows tuning of the RX FIFO fill threshold and timeout. (The latter is
only applicable to SCIFA and SCIFB).

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
---
 drivers/tty/serial/sh-sci.c | 87 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 034041e..46b3e84 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1183,6 +1183,66 @@ static void rx_fifo_timer_fn(unsigned long arg)
 	scif_set_rtrg(port, 1);
 }
 
+static ssize_t rx_trigger_show(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	struct sci_port *sci = to_sci_port(port);
+
+	return sprintf(buf, "%d\n", sci->rx_trigger);
+}
+
+static ssize_t rx_trigger_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf,
+				size_t count)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	struct sci_port *sci = to_sci_port(port);
+	long r;
+
+	if (kstrtol(buf, 0, &r) == -EINVAL)
+		return -EINVAL;
+	sci->rx_trigger = scif_set_rtrg(port, r);
+	scif_set_rtrg(port, 1);
+	return count;
+}
+
+static DEVICE_ATTR(rx_fifo_trigger, 0644, rx_trigger_show, rx_trigger_store);
+
+static ssize_t rx_fifo_timeout_show(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	struct sci_port *sci = to_sci_port(port);
+
+	return sprintf(buf, "%d\n", sci->rx_fifo_timeout);
+}
+
+static ssize_t rx_fifo_timeout_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf,
+				size_t count)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	struct sci_port *sci = to_sci_port(port);
+	long r;
+
+	if (kstrtol(buf, 0, &r) == -EINVAL)
+		return -EINVAL;
+	sci->rx_fifo_timeout = r;
+	scif_set_rtrg(port, 1);
+	if (r > 0)
+		setup_timer(&sci->rx_fifo_timer, rx_fifo_timer_fn,
+			    (unsigned long)sci);
+	return count;
+}
+
+static DEVICE_ATTR(rx_fifo_timeout, 0644, rx_fifo_timeout_show, rx_fifo_timeout_store);
+
+
 #ifdef CONFIG_SERIAL_SH_SCI_DMA
 static void sci_dma_tx_complete(void *arg)
 {
@@ -3030,6 +3090,15 @@ static int sci_remove(struct platform_device *dev)
 
 	sci_cleanup_single(port);
 
+	if (port->port.fifosize > 1) {
+		sysfs_remove_file(&dev->dev.kobj,
+				  &dev_attr_rx_fifo_trigger.attr);
+	}
+	if (port->port.type == PORT_SCIFA || port->port.type == PORT_SCIFB) {
+		sysfs_remove_file(&dev->dev.kobj,
+				  &dev_attr_rx_fifo_timeout.attr);
+	}
+
 	return 0;
 }
 
@@ -3195,6 +3264,24 @@ static int sci_probe(struct platform_device *dev)
 	if (ret)
 		return ret;
 
+	if (sp->port.fifosize > 1) {
+		ret = sysfs_create_file(&dev->dev.kobj,
+				&dev_attr_rx_fifo_trigger.attr);
+		if (ret)
+			return ret;
+	}
+	if (sp->port.type == PORT_SCIFA || sp->port.type ==  PORT_SCIFB) {
+		ret = sysfs_create_file(&dev->dev.kobj,
+				&dev_attr_rx_fifo_timeout.attr);
+		if (ret) {
+			if (sp->port.fifosize > 1) {
+				sysfs_remove_file(&dev->dev.kobj,
+					&dev_attr_rx_fifo_trigger.attr);
+			}
+			return ret;
+		}
+	}
+
 #ifdef CONFIG_SH_STANDARD_BIOS
 	sh_bios_gdb_detach();
 #endif
-- 
2.7.4

Re: [PATCH v2 6/7] serial: sh-sci: make RX FIFO parameters tunable via sysfs

[Geert Uytterhoeven]

On Mon, Jan 23, 2017 at 5:04 PM, Ulrich Hecht
<ulrich.hecht+renesas@gmail.com> wrote:
> Allows tuning of the RX FIFO fill threshold and timeout. (The latter is
> only applicable to SCIFA and SCIFB).
>
> Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2 7/7] arm64: dts: r8a7796: salvator-x: add SCIF1 (DEBUG1)

[Ulrich Hecht]

Enables the SCIF hooked up to the DEBUG1 connector.

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
---
 arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts b/arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts
index c7f40f8..498d971 100644
--- a/arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts
+++ b/arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts
@@ -18,6 +18,7 @@
 
 	aliases {
 		serial0 = &scif2;
+		serial1 = &scif1;
 		ethernet0 = &avb;
 	};
 
@@ -113,6 +114,11 @@
 		function = "avb";
 	};
 
+	scif1_pins: scif1 {
+		groups = "scif1_data_a", "scif1_ctrl";
+		function = "scif1";
+	};
+
 	scif2_pins: scif2 {
 		groups = "scif2_data_a";
 		function = "scif2";
@@ -239,6 +245,14 @@
 	status = "okay";
 };
 
+&scif1 {
+	pinctrl-0 = <&scif1_pins>;
+	pinctrl-names = "default";
+
+	uart-has-rtscts;
+	status = "okay";
+};
+
 &scif2 {
 	pinctrl-0 = <&scif2_pins>;
 	pinctrl-names = "default";
-- 
2.7.4

Re: [PATCH v2 7/7] arm64: dts: r8a7796: salvator-x: add SCIF1 (DEBUG1)

[Geert Uytterhoeven]

Hi Uli,

On Mon, Jan 23, 2017 at 5:04 PM, Ulrich Hecht
<ulrich.hecht+renesas@gmail.com> wrote:
> Enables the SCIF hooked up to the DEBUG1 connector.
>
> Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

> ---
>  arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts b/arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts
> index c7f40f8..498d971 100644
> --- a/arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts
> +++ b/arch/arm64/boot/dts/renesas/r8a7796-salvator-x.dts
> @@ -18,6 +18,7 @@
>
>         aliases {
>                 serial0 = &scif2;
> +               serial1 = &scif1;

While the patch is acceptable as-is, my question is still valid:
Is there any specific reason you chose scif1 over hscif1?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2 7/7] arm64: dts: r8a7796: salvator-x: add SCIF1 (DEBUG1)

[Ulrich Hecht]

On Tue, Jan 24, 2017 at 9:08 AM, Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
> While the patch is acceptable as-is, my question is still valid:
> Is there any specific reason you chose scif1 over hscif1?

Conservatism. :)

CU
Uli