serial: sh-sci: FIFO sizing helper consolidation.

This consolidates all of the TX/RX fill/room nonsense in to a single set
of fairly heavyweight definitions. The implementation goes in descending
order of complexity, testing the register map for capabilities until we
run out of options and do it the legacy SCI way. Masks are derived
directly from the per-port FIFO size, meaning that platforms with FIFO
sizes not matching the standard port types will still need to manually
fix them up.

This also fixes up a number of issues such as tx_empty being completely
bogus for SCI and IrDA ports, some ports using masks smaller or greater
than their FIFO size, and so forth.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

drivers/tty/serial/sh-sci.c

@@ -297,6 +297,8 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 	},
 };
 
+#define sci_getreg(up, offset)		(sci_regmap[to_sci_port(up)->cfg->regtype] + offset)
+
 /*
  * The "offset" here is rather misleading, in that it refers to an enum
  * value relative to the port mapping rather than the fixed offset
@@ -305,8 +307,7 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
  */
 static unsigned int sci_serial_in(struct uart_port *p, int offset)
 {
-	struct sci_port *s = to_sci_port(p);
-	struct plat_sci_reg *reg = sci_regmap[s->cfg->regtype] + offset;
+	struct plat_sci_reg *reg = sci_getreg(p, offset);
 
 	if (reg->size == 8)
 		return ioread8(p->membase + (reg->offset << p->regshift));
@@ -320,8 +321,7 @@ static unsigned int sci_serial_in(struct uart_port *p, int offset)
 
 static void sci_serial_out(struct uart_port *p, int offset, int value)
 {
-	struct sci_port *s = to_sci_port(p);
-	struct plat_sci_reg *reg = sci_regmap[s->cfg->regtype] + offset;
+	struct plat_sci_reg *reg = sci_getreg(p, offset);
 
 	if (reg->size == 8)
 		iowrite8(value, p->membase + (reg->offset << p->regshift));
@@ -433,108 +433,38 @@ static void sci_init_pins(struct uart_port *port, unsigned int cflag)
 		sci_out(port, SCSPTR, 0x0080); /* Set RTS = 1 */
 }
 
-#if defined(CONFIG_CPU_SUBTYPE_SH7760) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7780) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7785) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7786)
-static int scif_txfill(struct uart_port *port)
-{
-	return sci_in(port, SCTFDR) & 0xff;
-}
-
-static int scif_txroom(struct uart_port *port)
+static int sci_txfill(struct uart_port *port)
 {
-	return SCIF_TXROOM_MAX - scif_txfill(port);
-}
+	struct plat_sci_reg *reg;
 
-static int scif_rxfill(struct uart_port *port)
-{
-	return sci_in(port, SCRFDR) & 0xff;
-}
-#elif defined(CONFIG_CPU_SUBTYPE_SH7763)
-static int scif_txfill(struct uart_port *port)
-{
-	if (port->mapbase == 0xffe00000 ||
-	    port->mapbase == 0xffe08000)
-		/* SCIF0/1*/
+	reg = sci_getreg(port, SCTFDR);
+	if (reg->size)
 		return sci_in(port, SCTFDR) & 0xff;
-	else
-		/* SCIF2 */
-		return sci_in(port, SCFDR) >> 8;
-}
 
-static int scif_txroom(struct uart_port *port)
-{
-	if (port->mapbase == 0xffe00000 ||
-	    port->mapbase == 0xffe08000)
-		/* SCIF0/1*/
-		return SCIF_TXROOM_MAX - scif_txfill(port);
-	else
-		/* SCIF2 */
-		return SCIF2_TXROOM_MAX - scif_txfill(port);
-}
-
-static int scif_rxfill(struct uart_port *port)
-{
-	if ((port->mapbase == 0xffe00000) ||
-	    (port->mapbase == 0xffe08000)) {
-		/* SCIF0/1*/
-		return sci_in(port, SCRFDR) & 0xff;
-	} else {
-		/* SCIF2 */
-		return sci_in(port, SCFDR) & SCIF2_RFDC_MASK;
-	}
-}
-#elif defined(CONFIG_ARCH_SH7372)
-static int scif_txfill(struct uart_port *port)
-{
-	if (port->type == PORT_SCIFA)
+	reg = sci_getreg(port, SCFDR);
+	if (reg->size)
 		return sci_in(port, SCFDR) >> 8;
-	else
-		return sci_in(port, SCTFDR);
-}
 
-static int scif_txroom(struct uart_port *port)
-{
-	return port->fifosize - scif_txfill(port);
-}
-
-static int scif_rxfill(struct uart_port *port)
-{
-	if (port->type == PORT_SCIFA)
-		return sci_in(port, SCFDR) & SCIF_RFDC_MASK;
-	else
-		return sci_in(port, SCRFDR);
-}
-#else
-static int scif_txfill(struct uart_port *port)
-{
-	return sci_in(port, SCFDR) >> 8;
-}
-
-static int scif_txroom(struct uart_port *port)
-{
-	return SCIF_TXROOM_MAX - scif_txfill(port);
-}
-
-static int scif_rxfill(struct uart_port *port)
-{
-	return sci_in(port, SCFDR) & SCIF_RFDC_MASK;
-}
-#endif
-
-static int sci_txfill(struct uart_port *port)
-{
 	return !(sci_in(port, SCxSR) & SCI_TDRE);
 }
 
 static int sci_txroom(struct uart_port *port)
 {
-	return !sci_txfill(port);
+	return port->fifosize - sci_txfill(port);
 }
 
 static int sci_rxfill(struct uart_port *port)
 {
+	struct plat_sci_reg *reg;
+
+	reg = sci_getreg(port, SCRFDR);
+	if (reg->size)
+		return sci_in(port, SCRFDR) & 0xff;
+
+	reg = sci_getreg(port, SCFDR);
+	if (reg->size)
+		return sci_in(port, SCFDR) & ((port->fifosize << 1) - 1);
+
 	return (sci_in(port, SCxSR) & SCxSR_RDxF(port)) != 0;
 }
 
@@ -574,10 +504,7 @@ static void sci_transmit_chars(struct uart_port *port)
 		return;
 	}
 
-	if (port->type == PORT_SCI)
 	count = sci_txroom(port);
-	else
-		count = scif_txroom(port);
 
 	do {
 		unsigned char c;
@@ -632,13 +559,8 @@ static void sci_receive_chars(struct uart_port *port)
 		return;
 
 	while (1) {
-		if (port->type == PORT_SCI)
-			count = sci_rxfill(port);
-		else
-			count = scif_rxfill(port);
-
 		/* Don't copy more bytes than there is room for in the buffer */
-		count = tty_buffer_request_room(tty, count);
+		count = tty_buffer_request_room(tty, sci_rxfill(port));
 
 		/* If for any reason we can't copy more data, we're done! */
 		if (count == 0)
@@ -1096,7 +1018,7 @@ static void sci_free_irq(struct sci_port *port)
 static unsigned int sci_tx_empty(struct uart_port *port)
 {
 	unsigned short status = sci_in(port, SCxSR);
-	unsigned short in_tx_fifo = scif_txfill(port);
+	unsigned short in_tx_fifo = sci_txfill(port);
 
 	return (status & SCxSR_TEND(port)) && !in_tx_fifo ? TIOCSER_TEMT : 0;
 }

drivers/tty/serial/sh-sci.h

@@ -2,26 +2,6 @@
 #include <linux/io.h>
 #include <linux/gpio.h>
 
-#if defined(CONFIG_CPU_SUBTYPE_SH7705) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7720) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7721) || \
-    defined(CONFIG_ARCH_SH73A0) || \
-    defined(CONFIG_ARCH_SH7367) || \
-    defined(CONFIG_ARCH_SH7377) || \
-    defined(CONFIG_ARCH_SH7372)
-# define SCIF_RFDC_MASK 0x007f
-# define SCIF_TXROOM_MAX 64
-#elif defined(CONFIG_CPU_SUBTYPE_SH7763)
-# define SCIF_RFDC_MASK 0x007f
-# define SCIF_TXROOM_MAX 64
-/* SH7763 SCIF2 support */
-# define SCIF2_RFDC_MASK 0x001f
-# define SCIF2_TXROOM_MAX 16
-#else
-# define SCIF_RFDC_MASK 0x001f
-# define SCIF_TXROOM_MAX 16
-#endif
-
 #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_TDxE(port)	(((port)->type == PORT_SCI) ? SCI_TDRE   : SCIF_TDFE)