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Subject[PATCH 20/25] serial: Add driver for the Altera JTAG UART
Date
From: Tobias Klauser <tklauser@distanz.ch>

Add an UART driver for the JTAG UART component available as a SOPC
(System on Programmable Chip) component for Altera FPGAs.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/serial/Kconfig | 21 ++
drivers/serial/Makefile | 1 +
drivers/serial/altera_jtaguart.c | 504 ++++++++++++++++++++++++++++++++++++++
include/linux/altera_jtaguart.h | 16 ++
include/linux/serial_core.h | 3 +
5 files changed, 545 insertions(+), 0 deletions(-)
create mode 100644 drivers/serial/altera_jtaguart.c
create mode 100644 include/linux/altera_jtaguart.h

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 577d276..f4050e6 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -1523,4 +1523,25 @@ config SERIAL_GRLIB_GAISLER_APBUART_CONSOLE
help
Support for running a console on the GRLIB APBUART

+config SERIAL_ALTERA_JTAGUART
+ tristate "Altera JTAG UART support"
+ select SERIAL_CORE
+ help
+ This driver supports the Altera JTAG UART port.
+
+config SERIAL_ALTERA_JTAGUART_CONSOLE
+ bool "Altera JTAG UART console support"
+ depends on SERIAL_ALTERA_JTAGUART=y
+ select SERIAL_CORE_CONSOLE
+ help
+ Enable a Altera JTAG UART port to be the system console.
+
+config SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS
+ bool "Bypass output when no connection"
+ depends on SERIAL_ALTERA_JTAGUART_CONSOLE
+ select SERIAL_CORE_CONSOLE
+ help
+ Bypass console output and keep going even if there is no
+ JTAG terminal connection with the host.
+
endmenu
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 328f107..7f9d225 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -82,3 +82,4 @@ obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
obj-$(CONFIG_SERIAL_QE) += ucc_uart.o
obj-$(CONFIG_SERIAL_TIMBERDALE) += timbuart.o
obj-$(CONFIG_SERIAL_GRLIB_GAISLER_APBUART) += apbuart.o
+obj-$(CONFIG_SERIAL_ALTERA_JTAGUART) += altera_jtaguart.o
diff --git a/drivers/serial/altera_jtaguart.c b/drivers/serial/altera_jtaguart.c
new file mode 100644
index 0000000..f9b49b5
--- /dev/null
+++ b/drivers/serial/altera_jtaguart.c
@@ -0,0 +1,504 @@
+/*
+ * altera_jtaguart.c -- Altera JTAG UART driver
+ *
+ * Based on mcf.c -- Freescale ColdFire UART driver
+ *
+ * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
+ * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
+ * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/console.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/altera_jtaguart.h>
+
+#define DRV_NAME "altera_jtaguart"
+
+/*
+ * Altera JTAG UART register definitions according to the Altera JTAG UART
+ * datasheet: http://www.altera.com/literature/hb/nios2/n2cpu_nii51009.pdf
+ */
+
+#define ALTERA_JTAGUART_SIZE 8
+
+#define ALTERA_JTAGUART_DATA_REG 0
+
+#define ALTERA_JTAGUART_DATA_DATA_MSK 0x000000FF
+#define ALTERA_JTAGUART_DATA_RVALID_MSK 0x00008000
+#define ALTERA_JTAGUART_DATA_RAVAIL_MSK 0xFFFF0000
+#define ALTERA_JTAGUART_DATA_RAVAIL_OFF 16
+
+#define ALTERA_JTAGUART_CONTROL_REG 4
+
+#define ALTERA_JTAGUART_CONTROL_RE_MSK 0x00000001
+#define ALTERA_JTAGUART_CONTROL_WE_MSK 0x00000002
+#define ALTERA_JTAGUART_CONTROL_RI_MSK 0x00000100
+#define ALTERA_JTAGUART_CONTROL_RI_OFF 8
+#define ALTERA_JTAGUART_CONTROL_WI_MSK 0x00000200
+#define ALTERA_JTAGUART_CONTROL_AC_MSK 0x00000400
+#define ALTERA_JTAGUART_CONTROL_WSPACE_MSK 0xFFFF0000
+#define ALTERA_JTAGUART_CONTROL_WSPACE_OFF 16
+
+/*
+ * Local per-uart structure.
+ */
+struct altera_jtaguart {
+ struct uart_port port;
+ unsigned int sigs; /* Local copy of line sigs */
+ unsigned long imr; /* Local IMR mirror */
+};
+
+static unsigned int altera_jtaguart_tx_empty(struct uart_port *port)
+{
+ return (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
+ ALTERA_JTAGUART_CONTROL_WSPACE_MSK) ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int altera_jtaguart_get_mctrl(struct uart_port *port)
+{
+ return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
+}
+
+static void altera_jtaguart_set_mctrl(struct uart_port *port, unsigned int sigs)
+{
+}
+
+static void altera_jtaguart_start_tx(struct uart_port *port)
+{
+ struct altera_jtaguart *pp =
+ container_of(port, struct altera_jtaguart, port);
+
+ pp->imr |= ALTERA_JTAGUART_CONTROL_WE_MSK;
+ writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
+}
+
+static void altera_jtaguart_stop_tx(struct uart_port *port)
+{
+ struct altera_jtaguart *pp =
+ container_of(port, struct altera_jtaguart, port);
+
+ pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK;
+ writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
+}
+
+static void altera_jtaguart_stop_rx(struct uart_port *port)
+{
+ struct altera_jtaguart *pp =
+ container_of(port, struct altera_jtaguart, port);
+
+ pp->imr &= ~ALTERA_JTAGUART_CONTROL_RE_MSK;
+ writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
+}
+
+static void altera_jtaguart_break_ctl(struct uart_port *port, int break_state)
+{
+}
+
+static void altera_jtaguart_enable_ms(struct uart_port *port)
+{
+}
+
+static void altera_jtaguart_set_termios(struct uart_port *port,
+ struct ktermios *termios,
+ struct ktermios *old)
+{
+ /* Just copy the old termios settings back */
+ if (old)
+ tty_termios_copy_hw(termios, old);
+}
+
+static void altera_jtaguart_rx_chars(struct altera_jtaguart *pp)
+{
+ struct uart_port *port = &pp->port;
+ unsigned char ch, flag;
+ unsigned long status;
+
+ while ((status = readl(port->membase + ALTERA_JTAGUART_DATA_REG)) &
+ ALTERA_JTAGUART_DATA_RVALID_MSK) {
+ ch = status & ALTERA_JTAGUART_DATA_DATA_MSK;
+ flag = TTY_NORMAL;
+ port->icount.rx++;
+
+ if (uart_handle_sysrq_char(port, ch))
+ continue;
+ uart_insert_char(port, 0, 0, ch, flag);
+ }
+
+ tty_flip_buffer_push(port->state->port.tty);
+}
+
+static void altera_jtaguart_tx_chars(struct altera_jtaguart *pp)
+{
+ struct uart_port *port = &pp->port;
+ struct circ_buf *xmit = &port->state->xmit;
+ unsigned int pending, count;
+
+ if (port->x_char) {
+ /* Send special char - probably flow control */
+ writel(port->x_char, port->membase + ALTERA_JTAGUART_DATA_REG);
+ port->x_char = 0;
+ port->icount.tx++;
+ return;
+ }
+
+ pending = uart_circ_chars_pending(xmit);
+ if (pending > 0) {
+ count = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
+ ALTERA_JTAGUART_CONTROL_WSPACE_MSK) >>
+ ALTERA_JTAGUART_CONTROL_WSPACE_OFF;
+ if (count > pending)
+ count = pending;
+ if (count > 0) {
+ pending -= count;
+ while (count--) {
+ writel(xmit->buf[xmit->tail],
+ port->membase + ALTERA_JTAGUART_DATA_REG);
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ port->icount.tx++;
+ }
+ if (pending < WAKEUP_CHARS)
+ uart_write_wakeup(port);
+ }
+ }
+
+ if (pending == 0) {
+ pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK;
+ writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
+ }
+}
+
+static irqreturn_t altera_jtaguart_interrupt(int irq, void *data)
+{
+ struct uart_port *port = data;
+ struct altera_jtaguart *pp =
+ container_of(port, struct altera_jtaguart, port);
+ unsigned int isr;
+
+ isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >>
+ ALTERA_JTAGUART_CONTROL_RI_OFF) & pp->imr;
+
+ spin_lock(&port->lock);
+
+ if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK)
+ altera_jtaguart_rx_chars(pp);
+ if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK)
+ altera_jtaguart_tx_chars(pp);
+
+ spin_unlock(&port->lock);
+
+ return IRQ_RETVAL(isr);
+}
+
+static void altera_jtaguart_config_port(struct uart_port *port, int flags)
+{
+ port->type = PORT_ALTERA_JTAGUART;
+
+ /* Clear mask, so no surprise interrupts. */
+ writel(0, port->membase + ALTERA_JTAGUART_CONTROL_REG);
+}
+
+static int altera_jtaguart_startup(struct uart_port *port)
+{
+ struct altera_jtaguart *pp =
+ container_of(port, struct altera_jtaguart, port);
+ unsigned long flags;
+ int ret;
+
+ ret = request_irq(port->irq, altera_jtaguart_interrupt, IRQF_DISABLED,
+ DRV_NAME, port);
+ if (ret) {
+ pr_err(DRV_NAME ": unable to attach Altera JTAG UART %d "
+ "interrupt vector=%d\n", port->line, port->irq);
+ return ret;
+ }
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ /* Enable RX interrupts now */
+ pp->imr = ALTERA_JTAGUART_CONTROL_RE_MSK;
+ writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ return 0;
+}
+
+static void altera_jtaguart_shutdown(struct uart_port *port)
+{
+ struct altera_jtaguart *pp =
+ container_of(port, struct altera_jtaguart, port);
+ unsigned long flags;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ /* Disable all interrupts now */
+ pp->imr = 0;
+ writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ free_irq(port->irq, port);
+}
+
+static const char *altera_jtaguart_type(struct uart_port *port)
+{
+ return (port->type == PORT_ALTERA_JTAGUART) ? "Altera JTAG UART" : NULL;
+}
+
+static int altera_jtaguart_request_port(struct uart_port *port)
+{
+ /* UARTs always present */
+ return 0;
+}
+
+static void altera_jtaguart_release_port(struct uart_port *port)
+{
+ /* Nothing to release... */
+}
+
+static int altera_jtaguart_verify_port(struct uart_port *port,
+ struct serial_struct *ser)
+{
+ if (ser->type != PORT_UNKNOWN && ser->type != PORT_ALTERA_JTAGUART)
+ return -EINVAL;
+ return 0;
+}
+
+/*
+ * Define the basic serial functions we support.
+ */
+static struct uart_ops altera_jtaguart_ops = {
+ .tx_empty = altera_jtaguart_tx_empty,
+ .get_mctrl = altera_jtaguart_get_mctrl,
+ .set_mctrl = altera_jtaguart_set_mctrl,
+ .start_tx = altera_jtaguart_start_tx,
+ .stop_tx = altera_jtaguart_stop_tx,
+ .stop_rx = altera_jtaguart_stop_rx,
+ .enable_ms = altera_jtaguart_enable_ms,
+ .break_ctl = altera_jtaguart_break_ctl,
+ .startup = altera_jtaguart_startup,
+ .shutdown = altera_jtaguart_shutdown,
+ .set_termios = altera_jtaguart_set_termios,
+ .type = altera_jtaguart_type,
+ .request_port = altera_jtaguart_request_port,
+ .release_port = altera_jtaguart_release_port,
+ .config_port = altera_jtaguart_config_port,
+ .verify_port = altera_jtaguart_verify_port,
+};
+
+#define ALTERA_JTAGUART_MAXPORTS 1
+static struct altera_jtaguart altera_jtaguart_ports[ALTERA_JTAGUART_MAXPORTS];
+
+#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE)
+
+int __init early_altera_jtaguart_setup(struct altera_jtaguart_platform_uart
+ *platp)
+{
+ struct uart_port *port;
+ int i;
+
+ for (i = 0; i < ALTERA_JTAGUART_MAXPORTS && platp[i].mapbase; i++) {
+ port = &altera_jtaguart_ports[i].port;
+
+ port->line = i;
+ port->type = PORT_ALTERA_JTAGUART;
+ port->mapbase = platp[i].mapbase;
+ port->membase = ioremap(port->mapbase, ALTERA_JTAGUART_SIZE);
+ port->iotype = SERIAL_IO_MEM;
+ port->irq = platp[i].irq;
+ port->flags = ASYNC_BOOT_AUTOCONF;
+ port->ops = &altera_jtaguart_ops;
+ }
+
+ return 0;
+}
+
+#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)
+static void altera_jtaguart_console_putc(struct console *co, const char c)
+{
+ struct uart_port *port = &(altera_jtaguart_ports + co->index)->port;
+ unsigned long status;
+ unsigned long flags;
+
+ spin_lock_irqsave(&port->lock, flags);
+ while (((status = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG)) &
+ ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
+ if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) {
+ spin_unlock_irqrestore(&port->lock, flags);
+ return; /* no connection activity */
+ }
+ spin_unlock_irqrestore(&port->lock, flags);
+ cpu_relax();
+ spin_lock_irqsave(&port->lock, flags);
+ }
+ writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+#else
+static void altera_jtaguart_console_putc(struct console *co, const char c)
+{
+ struct uart_port *port = &(altera_jtaguart_ports + co->index)->port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&port->lock, flags);
+ while ((readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
+ ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
+ spin_unlock_irqrestore(&port->lock, flags);
+ cpu_relax();
+ spin_lock_irqsave(&port->lock, flags);
+ }
+ writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+#endif
+
+static void altera_jtaguart_console_write(struct console *co, const char *s,
+ unsigned int count)
+{
+ for (; count; count--, s++) {
+ altera_jtaguart_console_putc(co, *s);
+ if (*s == '\n')
+ altera_jtaguart_console_putc(co, '\r');
+ }
+}
+
+static int __init altera_jtaguart_console_setup(struct console *co,
+ char *options)
+{
+ struct uart_port *port;
+
+ if (co->index < 0 || co->index >= ALTERA_JTAGUART_MAXPORTS)
+ return -EINVAL;
+ port = &altera_jtaguart_ports[co->index].port;
+ if (port->membase == 0)
+ return -ENODEV;
+ return 0;
+}
+
+static struct uart_driver altera_jtaguart_driver;
+
+static struct console altera_jtaguart_console = {
+ .name = "ttyJ",
+ .write = altera_jtaguart_console_write,
+ .device = uart_console_device,
+ .setup = altera_jtaguart_console_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+ .data = &altera_jtaguart_driver,
+};
+
+static int __init altera_jtaguart_console_init(void)
+{
+ register_console(&altera_jtaguart_console);
+ return 0;
+}
+
+console_initcall(altera_jtaguart_console_init);
+
+#define ALTERA_JTAGUART_CONSOLE (&altera_jtaguart_console)
+
+#else
+
+#define ALTERA_JTAGUART_CONSOLE NULL
+
+#endif /* CONFIG_ALTERA_JTAGUART_CONSOLE */
+
+static struct uart_driver altera_jtaguart_driver = {
+ .owner = THIS_MODULE,
+ .driver_name = "altera_jtaguart",
+ .dev_name = "ttyJ",
+ .major = ALTERA_JTAGUART_MAJOR,
+ .minor = ALTERA_JTAGUART_MINOR,
+ .nr = ALTERA_JTAGUART_MAXPORTS,
+ .cons = ALTERA_JTAGUART_CONSOLE,
+};
+
+static int __devinit altera_jtaguart_probe(struct platform_device *pdev)
+{
+ struct altera_jtaguart_platform_uart *platp = pdev->dev.platform_data;
+ struct uart_port *port;
+ int i;
+
+ for (i = 0; i < ALTERA_JTAGUART_MAXPORTS && platp[i].mapbase; i++) {
+ port = &altera_jtaguart_ports[i].port;
+
+ port->line = i;
+ port->type = PORT_ALTERA_JTAGUART;
+ port->mapbase = platp[i].mapbase;
+ port->membase = ioremap(port->mapbase, ALTERA_JTAGUART_SIZE);
+ port->iotype = SERIAL_IO_MEM;
+ port->irq = platp[i].irq;
+ port->ops = &altera_jtaguart_ops;
+ port->flags = ASYNC_BOOT_AUTOCONF;
+
+ uart_add_one_port(&altera_jtaguart_driver, port);
+ }
+
+ return 0;
+}
+
+static int __devexit altera_jtaguart_remove(struct platform_device *pdev)
+{
+ struct uart_port *port;
+ int i;
+
+ for (i = 0; i < ALTERA_JTAGUART_MAXPORTS; i++) {
+ port = &altera_jtaguart_ports[i].port;
+ if (port)
+ uart_remove_one_port(&altera_jtaguart_driver, port);
+ }
+
+ return 0;
+}
+
+static struct platform_driver altera_jtaguart_platform_driver = {
+ .probe = altera_jtaguart_probe,
+ .remove = __devexit_p(altera_jtaguart_remove),
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init altera_jtaguart_init(void)
+{
+ int rc;
+
+ rc = uart_register_driver(&altera_jtaguart_driver);
+ if (rc)
+ return rc;
+ rc = platform_driver_register(&altera_jtaguart_platform_driver);
+ if (rc) {
+ uart_unregister_driver(&altera_jtaguart_driver);
+ return rc;
+ }
+ return 0;
+}
+
+static void __exit altera_jtaguart_exit(void)
+{
+ platform_driver_unregister(&altera_jtaguart_platform_driver);
+ uart_unregister_driver(&altera_jtaguart_driver);
+}
+
+module_init(altera_jtaguart_init);
+module_exit(altera_jtaguart_exit);
+
+MODULE_DESCRIPTION("Altera JTAG UART driver");
+MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/altera_jtaguart.h b/include/linux/altera_jtaguart.h
new file mode 100644
index 0000000..953b178
--- /dev/null
+++ b/include/linux/altera_jtaguart.h
@@ -0,0 +1,16 @@
+/*
+ * altera_jtaguart.h -- Altera JTAG UART driver defines.
+ */
+
+#ifndef __ALTJUART_H
+#define __ALTJUART_H
+
+#define ALTERA_JTAGUART_MAJOR 204
+#define ALTERA_JTAGUART_MINOR 186
+
+struct altera_jtaguart_platform_uart {
+ unsigned long mapbase; /* Physical address base */
+ unsigned int irq; /* Interrupt vector */
+};
+
+#endif /* __ALTJUART_H */
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 78dd1e7..ade1536 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -182,6 +182,9 @@
/* Aeroflex Gaisler GRLIB APBUART */
#define PORT_APBUART 90

+/* Altera UARTs */
+#define PORT_ALTERA_JTAGUART 91
+
#ifdef __KERNEL__

#include <linux/compiler.h>
--
1.7.0.3


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