diff mbox

serial: sh-sci: Support for variable HSCIF hardware RX timeout

Message ID 1505835844-3320-1-git-send-email-ulrich.hecht+renesas@gmail.com (mailing list archive)
State Superseded
Delegated to: Geert Uytterhoeven
Headers show

Commit Message

Ulrich Hecht Sept. 19, 2017, 3:44 p.m. UTC 
HSCIF has facilities that allow changing the timeout after which an RX
interrupt is triggered even if the FIFO is not filled. This patch allows
changing the default (15 bits of silence) using the existing sysfs
attribute "rx_fifo_timeout".

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
---
 drivers/tty/serial/sh-sci.c | 51 ++++++++++++++++++++++++++++++++-------------
 drivers/tty/serial/sh-sci.h |  3 +++
 2 files changed, 39 insertions(+), 15 deletions(-)

Comments

Geert Uytterhoeven Sept. 21, 2017, 1:47 p.m. UTC | #1 
Hi Ulrich,

On Tue, Sep 19, 2017 at 5:44 PM, Ulrich Hecht
<ulrich.hecht+renesas@gmail.com> wrote:
> HSCIF has facilities that allow changing the timeout after which an RX
> interrupt is triggered even if the FIFO is not filled. This patch allows
> changing the default (15 bits of silence) using the existing sysfs
> attribute "rx_fifo_timeout".
>
> Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>

Thanks for your patch!

> --- a/drivers/tty/serial/sh-sci.c
> +++ b/drivers/tty/serial/sh-sci.c
> @@ -152,6 +152,7 @@ struct sci_port {
>         int                             rx_trigger;
>         struct timer_list               rx_fifo_timer;
>         int                             rx_fifo_timeout;
> +       u16                             hscif_tot;

Shouldn't this field be reset to zero in sci_init_single(), like
rx_fifo_timeout?

> @@ -1107,8 +1108,14 @@ static ssize_t rx_fifo_timeout_show(struct device *dev,
>  {
>         struct uart_port *port = dev_get_drvdata(dev);
>         struct sci_port *sci = to_sci_port(port);
> +       u16 v;

int, to preserve all bits from rx_fifo_timeout.

>
> -       return sprintf(buf, "%d\n", sci->rx_fifo_timeout);
> +       if (port->type == PORT_HSCIF)
> +               v = sci->hscif_tot >> HSSCR_TOT_SHIFT;
> +       else
> +               v = sci->rx_fifo_timeout;
> +
> +       return sprintf(buf, "%d\n", v);
>  }

> @@ -1124,11 +1131,19 @@ static ssize_t rx_fifo_timeout_store(struct device *dev,
>         ret = kstrtol(buf, 0, &r);
>         if (ret)
>                 return ret;
> -       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);
> +
> +       if (port->type == PORT_HSCIF) {
> +               if (r < 0 || r > 3)
> +                       return -EINVAL;
> +               sci->hscif_tot = r << HSSCR_TOT_SHIFT;
> +       } else {
> +               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);
> +       }

So this sysfs parameter uses slightly different units depending on serial port
type (HSCIF is in 15 Elementary Time Units aka 1.5 frames, SCIF[AB] is in
frames). Do we care?

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
diff mbox

Patch

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 784dd42..99eac92 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -152,6 +152,7 @@  struct sci_port {
 	int				rx_trigger;
 	struct timer_list		rx_fifo_timer;
 	int				rx_fifo_timeout;
+	u16				hscif_tot;
 
 	bool has_rtscts;
 	bool autorts;
@@ -1107,8 +1108,14 @@  static ssize_t rx_fifo_timeout_show(struct device *dev,
 {
 	struct uart_port *port = dev_get_drvdata(dev);
 	struct sci_port *sci = to_sci_port(port);
+	u16 v;
 
-	return sprintf(buf, "%d\n", sci->rx_fifo_timeout);
+	if (port->type == PORT_HSCIF)
+		v = sci->hscif_tot >> HSSCR_TOT_SHIFT;
+	else
+		v = sci->rx_fifo_timeout;
+
+	return sprintf(buf, "%d\n", v);
 }
 
 static ssize_t rx_fifo_timeout_store(struct device *dev,
@@ -1124,11 +1131,19 @@  static ssize_t rx_fifo_timeout_store(struct device *dev,
 	ret = kstrtol(buf, 0, &r);
 	if (ret)
 		return ret;
-	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);
+
+	if (port->type == PORT_HSCIF) {
+		if (r < 0 || r > 3)
+			return -EINVAL;
+		sci->hscif_tot = r << HSSCR_TOT_SHIFT;
+	} else {
+		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;
 }
 
@@ -2037,9 +2052,13 @@  static void sci_shutdown(struct uart_port *port)
 	spin_lock_irqsave(&port->lock, flags);
 	sci_stop_rx(port);
 	sci_stop_tx(port);
-	/* Stop RX and TX, disable related interrupts, keep clock source */
+	/*
+	 * Stop RX and TX, disable related interrupts, keep clock source
+	 * and HSCIF TOT bits
+	 */
 	scr = serial_port_in(port, SCSCR);
-	serial_port_out(port, SCSCR, scr & (SCSCR_CKE1 | SCSCR_CKE0));
+	serial_port_out(port, SCSCR, scr &
+			(SCSCR_CKE1 | SCSCR_CKE0 | s->hscif_tot));
 	spin_unlock_irqrestore(&port->lock, flags);
 
 #ifdef CONFIG_SERIAL_SH_SCI_DMA
@@ -2186,7 +2205,7 @@  static void sci_reset(struct uart_port *port)
 	unsigned int status;
 	struct sci_port *s = to_sci_port(port);
 
-	serial_port_out(port, SCSCR, 0x00);	/* TE=0, RE=0, CKE1=0 */
+	serial_port_out(port, SCSCR, s->hscif_tot);	/* TE=0, RE=0, CKE1=0 */
 
 	reg = sci_getreg(port, SCFCR);
 	if (reg->size)
@@ -2356,7 +2375,7 @@  static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
 		dev_dbg(port->dev,
 			 "SCR 0x%x SMR 0x%x BRR %u CKS 0x%x DL %u SRR %u\n",
 			 scr_val, smr_val, brr, sccks, dl, srr);
-		serial_port_out(port, SCSCR, scr_val);
+		serial_port_out(port, SCSCR, scr_val | s->hscif_tot);
 		serial_port_out(port, SCSMR, smr_val);
 		serial_port_out(port, SCBRR, brr);
 		if (sci_getreg(port, HSSRR)->size)
@@ -2370,7 +2389,7 @@  static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
 		smr_val |= serial_port_in(port, SCSMR) &
 			   (SCSMR_CKEDG | SCSMR_SRC_MASK | SCSMR_CKS);
 		dev_dbg(port->dev, "SCR 0x%x SMR 0x%x\n", scr_val, smr_val);
-		serial_port_out(port, SCSCR, scr_val);
+		serial_port_out(port, SCSCR, scr_val | s->hscif_tot);
 		serial_port_out(port, SCSMR, smr_val);
 	}
 
@@ -2407,7 +2426,7 @@  static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
 	scr_val |= SCSCR_RE | SCSCR_TE |
 		   (s->cfg->scscr & ~(SCSCR_CKE1 | SCSCR_CKE0));
 	dev_dbg(port->dev, "SCSCR 0x%x\n", scr_val);
-	serial_port_out(port, SCSCR, scr_val);
+	serial_port_out(port, SCSCR, scr_val | s->hscif_tot);
 	if ((srr + 1 == 5) &&
 	    (port->type == PORT_SCIFA || port->type == PORT_SCIFB)) {
 		/*
@@ -2860,7 +2879,7 @@  static void serial_console_write(struct console *co, const char *s,
 	ctrl_temp = SCSCR_RE | SCSCR_TE |
 		    (sci_port->cfg->scscr & ~(SCSCR_CKE1 | SCSCR_CKE0)) |
 		    (ctrl & (SCSCR_CKE1 | SCSCR_CKE0));
-	serial_port_out(port, SCSCR, ctrl_temp);
+	serial_port_out(port, SCSCR, ctrl_temp | sci_port->hscif_tot);
 
 	uart_console_write(port, s, count, serial_console_putchar);
 
@@ -2988,7 +3007,8 @@  static int sci_remove(struct platform_device *dev)
 		sysfs_remove_file(&dev->dev.kobj,
 				  &dev_attr_rx_fifo_trigger.attr);
 	}
-	if (port->port.type == PORT_SCIFA || port->port.type == PORT_SCIFB) {
+	if (port->port.type == PORT_SCIFA || port->port.type == PORT_SCIFB ||
+	    port->port.type == PORT_HSCIF) {
 		sysfs_remove_file(&dev->dev.kobj,
 				  &dev_attr_rx_fifo_timeout.attr);
 	}
@@ -3173,7 +3193,8 @@  static int sci_probe(struct platform_device *dev)
 		if (ret)
 			return ret;
 	}
-	if (sp->port.type == PORT_SCIFA || sp->port.type ==  PORT_SCIFB) {
+	if (sp->port.type == PORT_SCIFA || sp->port.type == PORT_SCIFB ||
+	    sp->port.type == PORT_HSCIF) {
 		ret = sysfs_create_file(&dev->dev.kobj,
 				&dev_attr_rx_fifo_timeout.attr);
 		if (ret) {
diff --git a/drivers/tty/serial/sh-sci.h b/drivers/tty/serial/sh-sci.h
index 971b2ab..2b708cc 100644
--- a/drivers/tty/serial/sh-sci.h
+++ b/drivers/tty/serial/sh-sci.h
@@ -62,6 +62,9 @@  enum {
 #define SCSCR_TDRQE	BIT(15)	/* Tx Data Transfer Request Enable */
 #define SCSCR_RDRQE	BIT(14)	/* Rx Data Transfer Request Enable */
 
+/* Serial Control Register, HSCIF-only bits */
+#define HSSCR_TOT_SHIFT	14
+
 /* SCxSR (Serial Status Register) on SCI */
 #define SCI_TDRE	BIT(7)	/* Transmit Data Register Empty */
 #define SCI_RDRF	BIT(6)	/* Receive Data Register Full */