---

yaml
---
r: 267305
b: refs/heads/master
c: 6b1a98d
h: refs/heads/master
i:
  267303: 25ebca0
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4834d028978583dfe8e1fc19f1180ceb03d8dfb7
+refs/heads/master: 6b1a98d1c4851235d9b6764b3f7b7db7909fc760

trunk/drivers/tty/serial/8250_dw.c

@@ -0,0 +1,99 @@
+/*
+ * Synopsys DesignWare specific 8250 operations.
+ *
+ * Copyright 2011 Picochip, Jamie Iles.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * The Synopsys DesignWare 8250 has an extra feature whereby it detects if the
+ * LCR is written whilst busy.  If it is, then a busy detect interrupt is
+ * raised, the LCR needs to be rewritten and the uart status register read.
+ */
+#include <linux/io.h>
+#include <linux/serial_8250.h>
+#include <linux/serial_core.h>
+#include <linux/serial_reg.h>
+#include <linux/slab.h>
+
+struct dw8250_data {
+	int	last_lcr;
+};
+
+static void dw8250_serial_out(struct uart_port *p, int offset, int value)
+{
+	struct dw8250_data *d = p->private_data;
+
+	if (offset == UART_LCR)
+		d->last_lcr = value;
+
+	offset <<= p->regshift;
+	writeb(value, p->membase + offset);
+}
+
+static unsigned int dw8250_serial_in(struct uart_port *p, int offset)
+{
+	offset <<= p->regshift;
+
+	return readb(p->membase + offset);
+}
+
+static void dw8250_serial_out32(struct uart_port *p, int offset,
+				int value)
+{
+	struct dw8250_data *d = p->private_data;
+
+	if (offset == UART_LCR)
+		d->last_lcr = value;
+
+	offset <<= p->regshift;
+	writel(value, p->membase + offset);
+}
+
+static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
+{
+	offset <<= p->regshift;
+
+	return readl(p->membase + offset);
+}
+
+/* Offset for the DesignWare's UART Status Register. */
+#define UART_USR	0x1f
+
+static int dw8250_handle_irq(struct uart_port *p)
+{
+	struct dw8250_data *d = p->private_data;
+	unsigned int iir = p->serial_in(p, UART_IIR);
+
+	if (serial8250_handle_irq(p, iir)) {
+		return 1;
+	} else if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
+		/* Clear the USR and write the LCR again. */
+		(void)p->serial_in(p, UART_USR);
+		p->serial_out(p, d->last_lcr, UART_LCR);
+
+		return 1;
+	}
+
+	return 0;
+}
+
+int serial8250_use_designware_io(struct uart_port *up)
+{
+	up->private_data = kzalloc(sizeof(struct dw8250_data), GFP_KERNEL);
+	if (!up->private_data)
+		return -ENOMEM;
+
+	if (up->iotype == UPIO_MEM32) {
+		up->serial_out = dw8250_serial_out32;
+		up->serial_in = dw8250_serial_in32;
+	} else {
+		up->serial_out = dw8250_serial_out;
+		up->serial_in = dw8250_serial_in;
+	}
+	up->handle_irq = dw8250_handle_irq;
+
+	return 0;
+}

trunk/drivers/tty/serial/Kconfig

@@ -267,6 +267,13 @@ config SERIAL_8250_RM9K
 	  port hardware found on MIPS RM9122 and similar processors.
 	  If unsure, say N.
 
+config SERIAL_8250_DW
+	bool "Support for Synopsys DesignWare 8250 quirks"
+	depends on SERIAL_8250
+	help
+	  Selecting this option will enable handling of the extra features
+	  present in the Synopsys DesignWare APB UART.
+
 comment "Non-8250 serial port support"
 
 config SERIAL_AMBA_PL010

trunk/drivers/tty/serial/Makefile

@@ -28,6 +28,7 @@ obj-$(CONFIG_SERIAL_8250_BOCA) += 8250_boca.o
 obj-$(CONFIG_SERIAL_8250_EXAR_ST16C554) += 8250_exar_st16c554.o
 obj-$(CONFIG_SERIAL_8250_HUB6) += 8250_hub6.o
 obj-$(CONFIG_SERIAL_8250_MCA) += 8250_mca.o
+obj-$(CONFIG_SERIAL_8250_DW) += 8250_dw.o
 obj-$(CONFIG_SERIAL_AMBA_PL010) += amba-pl010.o
 obj-$(CONFIG_SERIAL_AMBA_PL011) += amba-pl011.o
 obj-$(CONFIG_SERIAL_CLPS711X) += clps711x.o

trunk/include/linux/serial_8250.h

@@ -86,5 +86,13 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir);
 extern void serial8250_set_isa_configurator(void (*v)
 					(int port, struct uart_port *up,
 						unsigned short *capabilities));
+#ifndef SERIAL_8250_DW
+extern int serial8250_use_designware_io(struct uart_port *up);
+#else
+static inline int serial8250_use_designware_io(struct uart_port *up)
+{
+	return -EIO;
+}
+#endif
 
 #endif