serial: sh-sci: Consolidate RXD pin handling.

Non-SCI parts do not have the special port reg necessary for cases where
the RX and SCI pins are muxed and need to be manually polled, so these
like always fall back on the normal FIFO processing paths. SH7760 is in a
class in and of itself with regards to mapping its SIM card interface via
the SCI port class despite not having any of the RXD lines wired up and
so implicitly behaving more like a SCIF in this regard. Out of the other
CPUs, some support the port check via the same block while others do it
through an external SuperI/O, so it's not even possible to perform the
check relative to the ioremapped cookie offset, so the separate read
semantics are preserved here, too.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/kernel/cpu/sh3/setup-sh770x.c

@@ -108,6 +108,7 @@ static struct platform_device rtc_device = {
 
 static struct plat_sci_port scif0_platform_data = {
 	.mapbase	= 0xfffffe80,
+	.port_reg	= 0xa4000136,
 	.flags		= UPF_BOOT_AUTOCONF,
 	.scscr		= SCSCR_TE | SCSCR_RE,
 	.scbrr_algo_id	= SCBRR_ALGO_2,

arch/sh/kernel/cpu/sh4/setup-sh7750.c

@@ -38,6 +38,7 @@ static struct platform_device rtc_device = {
 
 static struct plat_sci_port sci_platform_data = {
 	.mapbase	= 0xffe00000,
+	.port_reg	= 0xffe0001C
 	.flags		= UPF_BOOT_AUTOCONF,
 	.scscr		= SCSCR_TE | SCSCR_RE,
 	.scbrr_algo_id	= SCBRR_ALGO_2,

drivers/tty/serial/sh-sci.c

@@ -363,6 +363,19 @@ static int sci_rxfill(struct uart_port *port)
 	return (sci_in(port, SCxSR) & SCxSR_RDxF(port)) != 0;
 }
 
+/*
+ * SCI helper for checking the state of the muxed port/RXD pins.
+ */
+static inline int sci_rxd_in(struct uart_port *port)
+{
+	struct sci_port *s = to_sci_port(port);
+
+	if (s->cfg->port_reg <= 0)
+		return 1;
+
+	return !!__raw_readb(s->cfg->port_reg);
+}
+
 /* ********************************************************************** *
  *                   the interrupt related routines                       *
  * ********************************************************************** */

drivers/tty/serial/sh-sci.h

@@ -287,32 +287,3 @@ SCIF_FNS(SCLSR,                         0,  0, 0x24, 16)
 #endif
 #define sci_in(port, reg) sci_##reg##_in(port)
 #define sci_out(port, reg, value) sci_##reg##_out(port, value)
-
-#if defined(CONFIG_CPU_SUBTYPE_SH7706) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7707) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7708) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7709)
-static inline int sci_rxd_in(struct uart_port *port)
-{
-	if (port->mapbase == 0xfffffe80)
-		return __raw_readb(SCPDR)&0x01 ? 1 : 0; /* SCI */
-	return 1;
-}
-#elif defined(CONFIG_CPU_SUBTYPE_SH7750)  || \
-      defined(CONFIG_CPU_SUBTYPE_SH7751)  || \
-      defined(CONFIG_CPU_SUBTYPE_SH7751R) || \
-      defined(CONFIG_CPU_SUBTYPE_SH7750R) || \
-      defined(CONFIG_CPU_SUBTYPE_SH7750S) || \
-      defined(CONFIG_CPU_SUBTYPE_SH7091)
-static inline int sci_rxd_in(struct uart_port *port)
-{
-	if (port->mapbase == 0xffe00000)
-		return __raw_readb(SCSPTR1)&0x01 ? 1 : 0; /* SCI */
-	return 1;
-}
-#else /* default case for non-SCI processors */
-static inline int sci_rxd_in(struct uart_port *port)
-{
-	return 1;
-}
-#endif

include/linux/serial_sci.h

@@ -86,6 +86,8 @@ struct plat_sci_port {
 	int		overrun_bit;
 	unsigned int	error_mask;
 
+	int		port_reg;
+
 	struct device	*dma_dev;
 
 	unsigned int	dma_slave_tx;