patches.renesas/0230-serial-sh-sci-implement-FIFO-threshold-register-sett.patch

From afc2193b96640358512cc4cafbda052da42bd4db Mon Sep 17 00:00:00 2001
From: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Date: Thu, 2 Feb 2017 18:10:16 +0100
Subject: [PATCH 230/255] serial: sh-sci: implement FIFO threshold register
 setting

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit a380ed461f66d1b843cf13380a43a5fe790b8430)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
 drivers/tty/serial/sh-sci.c |   59 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -976,6 +976,65 @@ static int sci_handle_breaks(struct uart
 	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)
 {