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Subject[RFC PATCH for Juno 2/2] tty: SBSA compatible UART
Date
From: Graeme Gregory <graeme.gregory@linaro.org>

This is a subset of pl011 UART which does not supprt DMA or baud rate
changing.

It is specified in the Server Base System Architecture document from
ARM.

Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
---
drivers/tty/Kconfig | 6 +
drivers/tty/Makefile | 1 +
drivers/tty/sbsauart.c | 328 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 335 insertions(+)
create mode 100644 drivers/tty/sbsauart.c

diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index b24aa01..50fe279 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -419,4 +419,10 @@ config DA_CONSOLE
help
This enables a console on a Dash channel.

+config SBSAUART_TTY
+ tristate "SBSA UART TTY Driver"
+ help
+ Console and system TTY driver for the SBSA UART which is defined
+ in the Server Base System Architecure document for ARM64 servers.
+
endif # TTY
diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile
index 58ad1c0..c3211c0 100644
--- a/drivers/tty/Makefile
+++ b/drivers/tty/Makefile
@@ -29,5 +29,6 @@ obj-$(CONFIG_SYNCLINK) += synclink.o
obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o
obj-$(CONFIG_GOLDFISH_TTY) += goldfish.o
obj-$(CONFIG_DA_TTY) += metag_da.o
+obj-$(CONFIG_SBSAUART_TTY) += sbsauart.o

obj-y += ipwireless/
diff --git a/drivers/tty/sbsauart.c b/drivers/tty/sbsauart.c
new file mode 100644
index 0000000..3a3ff88
--- /dev/null
+++ b/drivers/tty/sbsauart.c
@@ -0,0 +1,328 @@
+/*
+ * SBSA (Server Base System Architecture) Compatible UART driver
+ *
+ * Copyright (C) 2014 Linaro Ltd
+ *
+ * Author: Graeme Gregory <graeme.gregory@linaro.org>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/acpi.h>
+#include <linux/amba/serial.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+struct sbsa_tty {
+ struct tty_port port;
+ spinlock_t lock;
+ void __iomem *base;
+ u32 irq;
+ int opencount;
+ struct console console;
+};
+
+static struct tty_driver *sbsa_tty_driver;
+static struct sbsa_tty *sbsa_tty;
+
+#define SBSAUART_CHAR_MASK 0xFF
+
+static void sbsa_tty_do_write(const char *buf, unsigned count)
+{
+ unsigned long irq_flags;
+ struct sbsa_tty *qtty = sbsa_tty;
+ void __iomem *base = qtty->base;
+ unsigned n;
+
+ spin_lock_irqsave(&qtty->lock, irq_flags);
+ for (n = 0; n < count; n++) {
+ while (readw(base + UART01x_FR) & UART01x_FR_TXFF)
+ mdelay(10);
+ writew(buf[n], base + UART01x_DR);
+ }
+ spin_unlock_irqrestore(&qtty->lock, irq_flags);
+}
+
+static void sbsauart_fifo_to_tty(struct sbsa_tty *qtty)
+{
+ void __iomem *base = qtty->base;
+ unsigned int flag, max_count = 32;
+ u16 status, ch;
+
+ while (max_count--) {
+ status = readw(base + UART01x_FR);
+ if (status & UART01x_FR_RXFE)
+ break;
+
+ /* Take chars from the FIFO and update status */
+ ch = readw(base + UART01x_DR);
+ flag = TTY_NORMAL;
+
+ if (ch & UART011_DR_BE)
+ flag = TTY_BREAK;
+ else if (ch & UART011_DR_PE)
+ flag = TTY_PARITY;
+ else if (ch & UART011_DR_FE)
+ flag = TTY_FRAME;
+ else if (ch & UART011_DR_OE)
+ flag = TTY_OVERRUN;
+
+ ch &= SBSAUART_CHAR_MASK;
+
+ tty_insert_flip_char(&qtty->port, ch, flag);
+ }
+
+ tty_schedule_flip(&qtty->port);
+
+ /* Clear the RX IRQ */
+ writew(UART011_RXIC | UART011_RXIC, base + UART011_ICR);
+}
+
+static irqreturn_t sbsa_tty_interrupt(int irq, void *dev_id)
+{
+ struct sbsa_tty *qtty = sbsa_tty;
+ unsigned long irq_flags;
+
+ spin_lock_irqsave(&qtty->lock, irq_flags);
+ sbsauart_fifo_to_tty(qtty);
+ spin_unlock_irqrestore(&qtty->lock, irq_flags);
+
+ return IRQ_HANDLED;
+}
+
+static int sbsa_tty_open(struct tty_struct *tty, struct file *filp)
+{
+ struct sbsa_tty *qtty = sbsa_tty;
+
+ return tty_port_open(&qtty->port, tty, filp);
+}
+
+static void sbsa_tty_close(struct tty_struct *tty, struct file *filp)
+{
+ tty_port_close(tty->port, tty, filp);
+}
+
+static void sbsa_tty_hangup(struct tty_struct *tty)
+{
+ tty_port_hangup(tty->port);
+}
+
+static int sbsa_tty_write(struct tty_struct *tty, const unsigned char *buf,
+ int count)
+{
+ sbsa_tty_do_write(buf, count);
+ return count;
+}
+
+static int sbsa_tty_write_room(struct tty_struct *tty)
+{
+ return 32;
+}
+
+static void sbsa_tty_console_write(struct console *co, const char *b,
+ unsigned count)
+{
+ sbsa_tty_do_write(b, count);
+
+ if(b[count - 1] == '\n');
+ sbsa_tty_do_write("\r", 1);
+}
+
+static struct tty_driver *sbsa_tty_console_device(struct console *c,
+ int *index)
+{
+ *index = c->index;
+ return sbsa_tty_driver;
+}
+
+static int sbsa_tty_console_setup(struct console *co, char *options)
+{
+ if ((unsigned)co->index > 0)
+ return -ENODEV;
+ if (sbsa_tty->base == NULL)
+ return -ENODEV;
+ return 0;
+}
+
+static struct tty_port_operations sbsa_port_ops = {
+};
+
+static const struct tty_operations sbsa_tty_ops = {
+ .open = sbsa_tty_open,
+ .close = sbsa_tty_close,
+ .hangup = sbsa_tty_hangup,
+ .write = sbsa_tty_write,
+ .write_room = sbsa_tty_write_room,
+};
+
+static int sbsa_tty_create_driver(void)
+{
+ int ret;
+ struct tty_driver *tty;
+
+ sbsa_tty = kzalloc(sizeof(*sbsa_tty), GFP_KERNEL);
+ if (sbsa_tty == NULL) {
+ ret = -ENOMEM;
+ goto err_alloc_sbsa_tty_failed;
+ }
+ tty = alloc_tty_driver(1);
+ if (tty == NULL) {
+ ret = -ENOMEM;
+ goto err_alloc_tty_driver_failed;
+ }
+ tty->driver_name = "sbsauart";
+ tty->name = "ttySBSA";
+ tty->type = TTY_DRIVER_TYPE_SERIAL;
+ tty->subtype = SERIAL_TYPE_NORMAL;
+ tty->init_termios = tty_std_termios;
+ tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
+ TTY_DRIVER_DYNAMIC_DEV;
+ tty_set_operations(tty, &sbsa_tty_ops);
+ ret = tty_register_driver(tty);
+ if (ret)
+ goto err_tty_register_driver_failed;
+
+ sbsa_tty_driver = tty;
+ return 0;
+
+err_tty_register_driver_failed:
+ put_tty_driver(tty);
+err_alloc_tty_driver_failed:
+ kfree(sbsa_tty);
+ sbsa_tty = NULL;
+err_alloc_sbsa_tty_failed:
+ return ret;
+}
+
+static void sbsa_tty_delete_driver(void)
+{
+ tty_unregister_driver(sbsa_tty_driver);
+ put_tty_driver(sbsa_tty_driver);
+ sbsa_tty_driver = NULL;
+ kfree(sbsa_tty);
+ sbsa_tty = NULL;
+}
+
+static int sbsa_tty_probe(struct platform_device *pdev)
+{
+ struct sbsa_tty *qtty;
+ int ret = -EINVAL;
+ int i;
+ struct resource *r;
+ struct device *ttydev;
+ void __iomem *base;
+ u32 irq;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (r == NULL)
+ return -EINVAL;
+
+ base = ioremap(r->start, r->end - r->start);
+ if (base == NULL)
+ pr_err("sbsa_tty: unable to remap base\n");
+
+ r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (r == NULL)
+ goto err_unmap;
+
+ irq = r->start;
+
+ if (pdev->id > 0)
+ goto err_unmap;
+
+ ret = sbsa_tty_create_driver();
+ if (ret)
+ goto err_unmap;
+
+ qtty = sbsa_tty;
+ spin_lock_init(&qtty->lock);
+ tty_port_init(&qtty->port);
+ qtty->port.ops = &sbsa_port_ops;
+ qtty->base = base;
+ qtty->irq = irq;
+
+ /* Clear and Mask all IRQs */
+ writew(0, base + UART011_IMSC);
+ writew(0xFFFF, base + UART011_ICR);
+
+ ret = request_irq(irq, sbsa_tty_interrupt, IRQF_SHARED,
+ "sbsa_tty", pdev);
+ if (ret)
+ goto err_request_irq_failed;
+
+ /* Unmask the RX IRQ */
+ writew(UART011_RXIM | UART011_RTIM, base + UART011_IMSC);
+
+ ttydev = tty_port_register_device(&qtty->port, sbsa_tty_driver,
+ 0, &pdev->dev);
+ if (IS_ERR(ttydev)) {
+ ret = PTR_ERR(ttydev);
+ goto err_tty_register_device_failed;
+ }
+
+ strcpy(qtty->console.name, "ttySBSA");
+ qtty->console.write = sbsa_tty_console_write;
+ qtty->console.device = sbsa_tty_console_device;
+ qtty->console.setup = sbsa_tty_console_setup;
+ qtty->console.flags = CON_PRINTBUFFER;
+ qtty->console.index = pdev->id;
+ register_console(&qtty->console);
+
+ return 0;
+
+ tty_unregister_device(sbsa_tty_driver, i);
+err_tty_register_device_failed:
+ free_irq(irq, pdev);
+err_request_irq_failed:
+ sbsa_tty_delete_driver();
+err_unmap:
+ iounmap(base);
+ return ret;
+}
+
+static int sbsa_tty_remove(struct platform_device *pdev)
+{
+ struct sbsa_tty *qtty;
+
+ qtty = sbsa_tty;
+ unregister_console(&qtty->console);
+ tty_unregister_device(sbsa_tty_driver, pdev->id);
+ iounmap(qtty->base);
+ qtty->base = 0;
+ free_irq(qtty->irq, pdev);
+ sbsa_tty_delete_driver();
+ return 0;
+}
+
+static const struct acpi_device_id sbsa_acpi_match[] = {
+ { "ARMH0011", 0 },
+ { }
+};
+
+static struct platform_driver sbsa_tty_platform_driver = {
+ .probe = sbsa_tty_probe,
+ .remove = sbsa_tty_remove,
+ .driver = {
+ .name = "sbsa_tty",
+ .acpi_match_table = ACPI_PTR(sbsa_acpi_match),
+ }
+};
+
+module_platform_driver(sbsa_tty_platform_driver);
+
+MODULE_LICENSE("GPL v2");
--
1.7.9.5


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