This patch adds support for TTY interface on Serial Device Bus with
slave devices defined by ACPI HID's INT3511/INT3512.
HS-UART peripheral is found on Intel Atom BayTrail SoC's.
Signed-off-by: Shrirang Bagul <shrirang.bagul@xxxxxxxxxxxxx>
---
drivers/misc/Kconfig | 11 ++
drivers/misc/Makefile | 1 +
drivers/misc/intel-hsuart-serdev.c | 332 +++++++++++++++++++++++++++++++++++++
3 files changed, 344 insertions(+)
create mode 100644 drivers/misc/intel-hsuart-serdev.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 5d713008749b..c7a87670aa9e 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -499,6 +499,17 @@ config MISC_RTSX
tristate
default MISC_RTSX_PCI || MISC_RTSX_USB
+config HSUART_SERIAL_DEVICE
+ bool "Intel ACPI INT3511/12 Serial Device Bus slave TTY driver"
+ help
+ Say Y here if you want to use the TTY interface on Serial Device Bus with
+ slave devices defined by ACPI HID's INT3511/INT3512.
+ This HS-UART peripheral is found on Intel Atom BayTrail SoC's.
+
+ If unsure, say Y.
+ depends on ACPI
+ depends on TTY && SERIAL_DEV_BUS = y
+
source "drivers/misc/c2port/Kconfig"
source "drivers/misc/eeprom/Kconfig"
source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 20be70c3f118..b2285265eec6 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -57,3 +57,4 @@ obj-$(CONFIG_ASPEED_LPC_SNOOP) += aspeed-lpc-snoop.o
obj-$(CONFIG_PCI_ENDPOINT_TEST) += pci_endpoint_test.o
obj-$(CONFIG_OCXL) += ocxl/
obj-$(CONFIG_MISC_RTSX) += cardreader/
+obj-$(CONFIG_HSUART_SERIAL_DEVICE) += intel-hsuart-serdev.o
diff --git a/drivers/misc/intel-hsuart-serdev.c b/drivers/misc/intel-hsuart-serdev.c
new file mode 100644
index 000000000000..146c4789f224
--- /dev/null
+++ b/drivers/misc/intel-hsuart-serdev.c
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Shrirang Bagul <shrirang.bagul@xxxxxxxxxxxxx>
+ *
+ * Serial device bus slave driver for virtual HSUART ports on Intel Atom
+ * Baytrail SoC.
+ */
+
+#include <linux/acpi.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/serdev.h>
+#include <linux/serial.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+
+#define DRV_NAME "hsuart-tty"
+#define HSUART_NUM_MINORS 2
+
+static DEFINE_IDR(hsuart_minors);
+static DEFINE_MUTEX(table_lock);
+
+struct hsuart_data {
+ struct serdev_device *uart; /* the uart connected to the chip */
+ struct tty_driver *tty_drv; /* this is the user space tty */
+ struct device *dev; /* returned by tty_port_register_device() */
+ struct tty_port port;
+ unsigned int minor;
+ struct mutex mutex;
+};
+
+static struct hsuart_data *get_hsuart_by_minor(unsigned int minor)
+{
+ struct hsuart_data *data;
+
+ mutex_lock(&table_lock);
+ data = idr_find(&hsuart_minors, minor);
+ if (data) {
+ mutex_lock(&data->mutex);
+ tty_port_get(&data->port);
+ mutex_unlock(&data->mutex);
+ }
+ mutex_unlock(&table_lock);
+ return data;
+}
+
+static int alloc_minor(struct hsuart_data *data)
+{
+ int minor;
+
+ mutex_lock(&table_lock);
+ minor = idr_alloc(&hsuart_minors, data, 0, HSUART_NUM_MINORS,
+ GFP_KERNEL);
+ mutex_unlock(&table_lock);
+ if (minor >= 0)
+ data->minor = minor;
+ return minor;
+}
+
+static void release_minor(struct hsuart_data *data)
+{
+ int minor = data->minor;
+
+ data->minor = 0; /* Maybe should use an invalid value instead */
+ mutex_lock(&table_lock);
+ idr_remove(&hsuart_minors, minor);
+ mutex_unlock(&table_lock);
+}
+
+static int huart_receive_buf(struct serdev_device *serdev,
+ const unsigned char *rxdata, size_t count)
+{
+ struct hsuart_data *data =
+ (struct hsuart_data *) serdev_device_get_drvdata(serdev);
+ int ret;
+
+ dev_dbg(&data->uart->dev, "push %zu chars to tty port\n", count);
+ ret = tty_insert_flip_string(&data->port, rxdata, count);
+ if (ret != count)
+ dev_dbg(&data->uart->dev, "lost %zu characters\n", count - ret);
+ tty_flip_buffer_push(&data->port);
+
+ /* assume we have processed everything */
+ return count;
+}
+
+static void hsuart_write_wakeup(struct serdev_device *serdev)
+{
+ struct hsuart_data *data =
+ (struct hsuart_data *) serdev_device_get_drvdata(serdev);
+ struct tty_struct *tty = tty_port_tty_get(&data->port);
+
+ if (tty) {
+ tty_wakeup(tty);
+ tty_kref_put(tty);
+ }
+}
+
+static const struct serdev_device_ops hsuart_serdev_client_ops = {
+ .receive_buf = huart_receive_buf,
+ .write_wakeup = hsuart_write_wakeup,
+};
+
+static int hsuart_tty_install(struct tty_driver *driver, struct tty_struct *tty)
+{
+ struct hsuart_data *data;
+ int retval;
+
+ data = get_hsuart_by_minor(tty->index);
+ if (!data)
+ return -ENODEV;
+
+ retval = tty_standard_install(driver, tty);
+ if (retval)
+ goto error;
+
+ tty->driver_data = data;
+ return 0;
+error:
+ tty_port_put(&data->port);
+ return retval;
+}
+
+static int hsuart_tty_open(struct tty_struct *tty, struct file *file)
+{
+ struct hsuart_data *data = tty->driver_data;
+
+ return tty_port_open(&data->port, tty, file);
+}
+
+static void hsuart_tty_close(struct tty_struct *tty, struct file *file)
+{
+ struct hsuart_data *data = tty->driver_data;
+
+ tty_port_close(&data->port, tty, file);
+}
+
+static int hsuart_tty_write(struct tty_struct *tty, const unsigned char *buf,
+ int count)
+{
+ struct hsuart_data *data = tty->driver_data;
+
+ return serdev_device_write_buf(data->uart, buf, count);
+}
+
+static int hsuart_tty_write_room(struct tty_struct *tty)
+{
+ struct hsuart_data *data = tty->driver_data;
+
+ return serdev_device_write_room(data->uart);
+}
+
+static void hsuart_tty_flush_buffer(struct tty_struct *tty)
+{
+ struct hsuart_data *data = tty->driver_data;
+
+ serdev_device_write_flush(data->uart);
+}
+
+static void hsuart_tty_wait_until_sent(struct tty_struct *tty, int timeout)
+{
+ struct hsuart_data *data = tty->driver_data;
+
+ serdev_device_wait_until_sent(data->uart, timeout);
+}
+
+static void hsuart_tty_set_termios(struct tty_struct *tty,
+ struct ktermios *termios_old)
+{
+ struct hsuart_data *data = tty->driver_data;
+ unsigned int speed = tty_get_baud_rate(tty);
+
+ if (C_BAUD(tty) != B0)
+ serdev_device_set_baudrate(data->uart, speed);
+
+ serdev_device_set_flow_control(data->uart, C_CRTSCTS(tty));
+
+ if (C_PARENB(tty)) {
+ if (C_PARODD(tty))
+ serdev_device_set_parity(data->uart,
+ SERDEV_PARITY_ODD);
+ else
+ serdev_device_set_parity(data->uart,
+ SERDEV_PARITY_EVEN);
+ } else {
+ serdev_device_set_parity(data->uart, SERDEV_PARITY_NONE);
+ }
+}
+
+static int hsuart_tty_tiocmget(struct tty_struct *tty)
+{
+ struct hsuart_data *data = tty->driver_data;
+
+ return serdev_device_get_tiocm(data->uart);
+}
+
+static int hsuart_tty_tiocmset(struct tty_struct *tty, unsigned int set,
+ unsigned int clear)
+{
+ struct hsuart_data *data = tty->driver_data;
+
+ return serdev_device_set_tiocm(data->uart, set, clear);
+}
+
+static const struct tty_operations hsuart_tty_ops = {
+ .install = hsuart_tty_install,
+ .open = hsuart_tty_open,
+ .close = hsuart_tty_close,
+ .write = hsuart_tty_write,
+ .write_room = hsuart_tty_write_room,
+ .flush_buffer = hsuart_tty_flush_buffer,
+ .wait_until_sent = hsuart_tty_wait_until_sent,
+ .set_termios = hsuart_tty_set_termios,
+ .tiocmget = hsuart_tty_tiocmget,
+ .tiocmset = hsuart_tty_tiocmset,
+};
+
+static const struct tty_port_operations hsuart_port_ops = {
+};
+
+static int hsuart_probe(struct serdev_device *serdev)
+{
+ struct hsuart_data *data;
+ int minor;
+ int err = 0;
+
+ data = devm_kzalloc(&serdev->dev, sizeof(*data), GFP_KERNEL);
+ if (data == NULL)
+ return -ENOMEM;
+
+ serdev_device_set_drvdata(serdev, data);
+ data->uart = serdev;
+
+ serdev_device_set_client_ops(data->uart, &hsuart_serdev_client_ops);
+ serdev_device_open(data->uart);
+
+ serdev_device_set_baudrate(data->uart, 9600);
+ serdev_device_set_flow_control(data->uart, false);
+
+ /* allocate the tty driver */
+ data->tty_drv = tty_alloc_driver(HSUART_NUM_MINORS, 0);
+ if (!data->tty_drv) {
+ dev_err(&serdev->dev,
+ "failed to allcate tty driver\n");
+ err = -ENOMEM;
+ goto err_ttyfail;
+ }
+
+ /* initialize the tty driver */
+ data->tty_drv->driver_name = DRV_NAME;
+ data->tty_drv->name = "ttyHS";
+ data->tty_drv->major = 0;
+ data->tty_drv->minor_start = 0;
+ data->tty_drv->type = TTY_DRIVER_TYPE_SERIAL;
+ data->tty_drv->subtype = SERIAL_TYPE_NORMAL;
+ data->tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
+ data->tty_drv->init_termios = tty_std_termios;
+ data->tty_drv->init_termios.c_cflag = B9600 | CS8 |
+ CREAD | HUPCL | CLOCAL;
+ tty_set_operations(data->tty_drv, &hsuart_tty_ops);
+
+ minor = alloc_minor(data);
+ if (minor < 0) {
+ if (minor == -ENOSPC) {
+ dev_err(&serdev->dev,
+ "no more free minor numbers\n");
+ err = -ENODEV;
+ }
+ goto err_ttyfail;
+ }
+ mutex_init(&data->mutex);
+
+ /* register the tty driver */
+ err = tty_register_driver(data->tty_drv);
+ if (err) {
+ dev_err(&serdev->dev, "tty_register_driver failed(%d)\n", err);
+ put_tty_driver(data->tty_drv);
+ goto err_ttyfail;
+ }
+
+ tty_port_init(&data->port);
+ data->port.ops = &hsuart_port_ops;
+ data->dev = tty_port_register_device(&data->port, data->tty_drv,
+ minor, &serdev->dev);
+
+ return 0;
+
+err_ttyfail:
+ serdev_device_close(data->uart);
+ dev_err(&serdev->dev, "%s failed error: %d\n", __func__, err);
+
+ return err;
+}
+
+static void hsuart_remove(struct serdev_device *serdev)
+{
+ struct hsuart_data *data = serdev_device_get_drvdata(serdev);
+
+ serdev_device_close(data->uart);
+ tty_unregister_device(data->tty_drv, data->minor);
+ release_minor(data);
+
+ tty_unregister_driver(data->tty_drv);
+}
+
+static const struct acpi_device_id hsuart_acpi_match[] = {
+ {"INT3511", 0},
+ {"INT3512", 0},
+ { },
+};
+MODULE_DEVICE_TABLE(acpi, hsuart_acpi_match);
+
+static struct serdev_device_driver hsuart_tty_drv = {
+ .driver = {
+ .name = DRV_NAME,
+ .acpi_match_table = ACPI_PTR(hsuart_acpi_match),
+ },
+ .probe = hsuart_probe,
+ .remove = hsuart_remove,
+};
+
+module_serdev_device_driver(hsuart_tty_drv);
+
+MODULE_AUTHOR("Shrirang Bagul <shrirang.bagul@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Intel Atom (BayTrail) HS-UART serdev slave tty driver");
+MODULE_LICENSE("GPL v2");
--
2.14.1
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