diff options
| -rw-r--r-- | drivers/tty/serial/8250_dw.c | 99 | ||||
| -rw-r--r-- | drivers/tty/serial/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/tty/serial/Makefile | 1 | ||||
| -rw-r--r-- | include/linux/serial_8250.h | 8 |
4 files changed, 115 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250_dw.c b/drivers/tty/serial/8250_dw.c new file mode 100644 index 000000000000..e25782aeec7a --- /dev/null +++ b/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; +} diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index a9b307f582e1..d2d1cc2329b7 100644 --- a/drivers/tty/serial/Kconfig +++ b/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 diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile index 78748136ccc8..7b59958f50ec 100644 --- a/drivers/tty/serial/Makefile +++ b/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 diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index 1f05bbeac01e..09e2dbcd7ca3 100644 --- a/include/linux/serial_8250.h +++ b/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 |
