--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2018-2021, Intel Corporation. */
+
+#include "ice.h"
+#include "ice_lib.h"
+#include <linux/tty_driver.h>
+
+/**
+ * ice_gnss_read - Read data from internal GNSS module
+ * @work: GNSS read work structure
+ *
+ * Read the data from internal GNSS receiver, number of bytes read will be
+ * returned in *read_data parameter.
+ */
+static void ice_gnss_read(struct kthread_work *work)
+{
+ struct gnss_serial *gnss = container_of(work, struct gnss_serial,
+ read_work.work);
+ struct ice_aqc_link_topo_addr link_topo;
+ u8 i2c_params, bytes_read;
+ struct tty_port *port;
+ struct ice_pf *pf;
+ struct ice_hw *hw;
+ __be16 data_len_b;
+ char *buf = NULL;
+ u16 i, data_len;
+ int err = 0;
+
+ pf = gnss->back;
+ if (!pf || !gnss->tty || !gnss->tty->port) {
+ err = -EFAULT;
+ goto exit;
+ }
+
+ hw = &pf->hw;
+ port = gnss->tty->port;
+
+ buf = (char *)get_zeroed_page(GFP_KERNEL);
+ if (!buf) {
+ err = -ENOMEM;
+ goto exit;
+ }
+
+ memset(&link_topo, 0, sizeof(struct ice_aqc_link_topo_addr));
+ link_topo.topo_params.index = ICE_E810T_GNSS_I2C_BUS;
+ link_topo.topo_params.node_type_ctx |=
+ FIELD_PREP(ICE_AQC_LINK_TOPO_NODE_CTX_M,
+ ICE_AQC_LINK_TOPO_NODE_CTX_OVERRIDE);
+
+ i2c_params = ICE_GNSS_UBX_DATA_LEN_WIDTH |
+ ICE_AQC_I2C_USE_REPEATED_START;
+
+ /* Read data length in a loop, when it's not 0 the data is ready */
+ for (i = 0; i < ICE_MAX_UBX_READ_TRIES; i++) {
+ err = ice_aq_read_i2c(hw, link_topo, ICE_GNSS_UBX_I2C_BUS_ADDR,
+ cpu_to_le16(ICE_GNSS_UBX_DATA_LEN_H),
+ i2c_params, (u8 *)&data_len_b, NULL);
+ if (err)
+ goto exit_buf;
+
+ data_len = be16_to_cpu(data_len_b);
+ if (data_len != 0 && data_len != U16_MAX)
+ break;
+
+ mdelay(10);
+ }
+
+ data_len = min(data_len, (u16)PAGE_SIZE);
+ data_len = tty_buffer_request_room(port, data_len);
+ if (!data_len) {
+ err = -ENOMEM;
+ goto exit_buf;
+ }
+
+ /* Read received data */
+ for (i = 0; i < data_len; i += bytes_read) {
+ u16 bytes_left = data_len - i;
+
+ bytes_read = bytes_left < ICE_MAX_I2C_DATA_SIZE ? bytes_left :
+ ICE_MAX_I2C_DATA_SIZE;
+
+ err = ice_aq_read_i2c(hw, link_topo, ICE_GNSS_UBX_I2C_BUS_ADDR,
+ cpu_to_le16(ICE_GNSS_UBX_EMPTY_DATA),
+ bytes_read, &buf[i], NULL);
+ if (err)
+ goto exit_buf;
+ }
+
+ /* Send the data to the tty layer for users to read. This doesn't
+ * actually push the data through unless tty->low_latency is set.
+ */
+ tty_insert_flip_string(port, buf, i);
+ tty_flip_buffer_push(port);
+
+exit_buf:
+ free_page((unsigned long)buf);
+ kthread_queue_delayed_work(gnss->kworker, &gnss->read_work,
+ ICE_GNSS_TIMER_DELAY_TIME);
+exit:
+ if (err)
+ dev_dbg(ice_pf_to_dev(pf), "GNSS failed to read err=%d\n", err);
+}
+
+/**
+ * ice_gnss_struct_init - Initialize GNSS structure for the TTY
+ * @pf: Board private structure
+ */
+static struct gnss_serial *ice_gnss_struct_init(struct ice_pf *pf)
+{
+ struct device *dev = ice_pf_to_dev(pf);
+ struct kthread_worker *kworker;
+ struct gnss_serial *gnss;
+
+ gnss = kzalloc(sizeof(*gnss), GFP_KERNEL);
+ if (!gnss)
+ return NULL;
+
+ mutex_init(&gnss->gnss_mutex);
+ gnss->open_count = 0;
+ gnss->back = pf;
+ pf->gnss_serial = gnss;
+
+ kthread_init_delayed_work(&gnss->read_work, ice_gnss_read);
+ /* Allocate a kworker for handling work required for the GNSS TTY
+ * writes.
+ */
+ kworker = kthread_create_worker(0, "ice-gnss-%s", dev_name(dev));
+ if (!kworker) {
+ kfree(gnss);
+ return NULL;
+ }
+
+ gnss->kworker = kworker;
+
+ return gnss;
+}
+
+/**
+ * ice_gnss_tty_open - Initialize GNSS structures on TTY device open
+ * @tty: pointer to the tty_struct
+ * @filp: pointer to the file
+ *
+ * This routine is mandatory. If this routine is not filled in, the attempted
+ * open will fail with ENODEV.
+ */
+static int ice_gnss_tty_open(struct tty_struct *tty, struct file *filp)
+{
+ struct gnss_serial *gnss;
+ struct ice_pf *pf;
+
+ pf = (struct ice_pf *)tty->driver->driver_state;
+ if (!pf)
+ return -EFAULT;
+
+ /* Clear the pointer in case something fails */
+ tty->driver_data = NULL;
+
+ /* Get the serial object associated with this tty pointer */
+ gnss = pf->gnss_serial;
+ if (!gnss) {
+ /* Initialize GNSS struct on the first device open */
+ gnss = ice_gnss_struct_init(pf);
+ if (!gnss)
+ return -ENOMEM;
+ }
+
+ mutex_lock(&gnss->gnss_mutex);
+
+ /* Save our structure within the tty structure */
+ tty->driver_data = gnss;
+ gnss->tty = tty;
+ gnss->open_count++;
+ kthread_queue_delayed_work(gnss->kworker, &gnss->read_work, 0);
+
+ mutex_unlock(&gnss->gnss_mutex);
+
+ return 0;
+}
+
+/**
+ * ice_gnss_tty_close - Cleanup GNSS structures on tty device close
+ * @tty: pointer to the tty_struct
+ * @filp: pointer to the file
+ */
+static void ice_gnss_tty_close(struct tty_struct *tty, struct file *filp)
+{
+ struct gnss_serial *gnss = tty->driver_data;
+ struct ice_pf *pf;
+
+ if (!gnss)
+ return;
+
+ pf = (struct ice_pf *)tty->driver->driver_state;
+ if (!pf)
+ return;
+
+ mutex_lock(&gnss->gnss_mutex);
+
+ if (!gnss->open_count) {
+ /* Port was never opened */
+ dev_err(ice_pf_to_dev(pf), "GNSS port not opened\n");
+ goto exit;
+ }
+
+ gnss->open_count--;
+ if (gnss->open_count <= 0) {
+ /* Port is in shutdown state */
+ kthread_cancel_delayed_work_sync(&gnss->read_work);
+ }
+exit:
+ mutex_unlock(&gnss->gnss_mutex);
+}
+
+/**
+ * ice_gnss_tty_write - Dummy TTY write function to avoid kernel panic
+ * @tty: pointer to the tty_struct
+ * @buf: pointer to the user data
+ * @cnt: the number of characters that was able to be sent to the hardware (or
+ * queued to be sent at a later time)
+ */
+static int
+ice_gnss_tty_write(struct tty_struct *tty, const unsigned char *buf, int cnt)
+{
+ return 0;
+}
+
+/**
+ * ice_gnss_tty_write_room - Dummy TTY write_room function to avoid kernel panic
+ * @tty: pointer to the tty_struct
+ */
+static unsigned int ice_gnss_tty_write_room(struct tty_struct *tty)
+{
+ return 0;
+}
+
+static const struct tty_operations tty_gps_ops = {
+ .open = ice_gnss_tty_open,
+ .close = ice_gnss_tty_close,
+ .write = ice_gnss_tty_write,
+ .write_room = ice_gnss_tty_write_room,
+};
+
+/**
+ * ice_gnss_create_tty_driver - Create a TTY driver for GNSS
+ * @pf: Board private structure
+ */
+static struct tty_driver *ice_gnss_create_tty_driver(struct ice_pf *pf)
+{
+ struct device *dev = ice_pf_to_dev(pf);
+ const int ICE_TTYDRV_NAME_MAX = 14;
+ struct tty_driver *tty_driver;
+ char *ttydrv_name;
+ int err;
+
+ tty_driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW);
+ if (!tty_driver) {
+ dev_err(ice_pf_to_dev(pf), "Failed to allocate memory for GNSS TTY\n");
+ return NULL;
+ }
+
+ ttydrv_name = kzalloc(ICE_TTYDRV_NAME_MAX, GFP_KERNEL);
+ if (!ttydrv_name) {
+ tty_driver_kref_put(tty_driver);
+ return NULL;
+ }
+
+ snprintf(ttydrv_name, ICE_TTYDRV_NAME_MAX, "ttyGNSS_%02x%02x_",
+ (u8)pf->pdev->bus->number, (u8)PCI_SLOT(pf->pdev->devfn));
+
+ /* Initialize the tty driver*/
+ tty_driver->owner = THIS_MODULE;
+ tty_driver->driver_name = dev_driver_string(dev);
+ tty_driver->name = (const char *)ttydrv_name;
+ tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
+ tty_driver->subtype = SERIAL_TYPE_NORMAL;
+ tty_driver->init_termios = tty_std_termios;
+ tty_driver->init_termios.c_iflag &= ~INLCR;
+ tty_driver->init_termios.c_iflag |= IGNCR;
+ tty_driver->init_termios.c_oflag &= ~OPOST;
+ tty_driver->init_termios.c_lflag &= ~ICANON;
+ tty_driver->init_termios.c_cflag &= ~(CSIZE | CBAUD | CBAUDEX);
+ /* baud rate 9600 */
+ tty_termios_encode_baud_rate(&tty_driver->init_termios, 9600, 9600);
+ tty_driver->driver_state = pf;
+ tty_set_operations(tty_driver, &tty_gps_ops);
+
+ pf->gnss_serial = NULL;
+
+ tty_port_init(&pf->gnss_tty_port);
+ tty_port_link_device(&pf->gnss_tty_port, tty_driver, 0);
+
+ err = tty_register_driver(tty_driver);
+ if (err) {
+ dev_err(ice_pf_to_dev(pf), "Failed to register TTY driver err=%d\n",
+ err);
+
+ tty_port_destroy(&pf->gnss_tty_port);
+ kfree(ttydrv_name);
+ tty_driver_kref_put(pf->ice_gnss_tty_driver);
+
+ return NULL;
+ }
+
+ return tty_driver;
+}
+
+/**
+ * ice_gnss_init - Initialize GNSS TTY support
+ * @pf: Board private structure
+ */
+void ice_gnss_init(struct ice_pf *pf)
+{
+ struct tty_driver *tty_driver;
+
+ tty_driver = ice_gnss_create_tty_driver(pf);
+ if (!tty_driver)
+ return;
+
+ pf->ice_gnss_tty_driver = tty_driver;
+
+ set_bit(ICE_FLAG_GNSS, pf->flags);
+ dev_info(ice_pf_to_dev(pf), "GNSS TTY init successful\n");
+}
+
+/**
+ * ice_gnss_exit - Disable GNSS TTY support
+ * @pf: Board private structure
+ */
+void ice_gnss_exit(struct ice_pf *pf)
+{
+ if (!test_bit(ICE_FLAG_GNSS, pf->flags) || !pf->ice_gnss_tty_driver)
+ return;
+
+ tty_port_destroy(&pf->gnss_tty_port);
+
+ if (pf->gnss_serial) {
+ struct gnss_serial *gnss = pf->gnss_serial;
+
+ kthread_cancel_delayed_work_sync(&gnss->read_work);
+ kfree(gnss);
+ pf->gnss_serial = NULL;
+ }
+
+ tty_unregister_driver(pf->ice_gnss_tty_driver);
+ kfree(pf->ice_gnss_tty_driver->name);
+ tty_driver_kref_put(pf->ice_gnss_tty_driver);
+ pf->ice_gnss_tty_driver = NULL;
+}
+
+/**
+ * ice_gnss_is_gps_present - Check if GPS HW is present
+ * @hw: pointer to HW struct
+ */
+bool ice_gnss_is_gps_present(struct ice_hw *hw)
+{
+ if (!hw->func_caps.ts_func_info.src_tmr_owned)
+ return false;
+
+#if IS_ENABLED(CONFIG_PTP_1588_CLOCK)
+ if (ice_is_e810t(hw)) {
+ int err;
+ u8 data;
+
+ err = ice_read_pca9575_reg_e810t(hw, ICE_PCA9575_P0_IN, &data);
+ if (err || !!(data & ICE_E810T_P0_GNSS_PRSNT_N))
+ return false;
+ } else {
+ return false;
+ }
+#else
+ if (!ice_is_e810t(hw))
+ return false;
+#endif /* IS_ENABLED(CONFIG_PTP_1588_CLOCK) */
+
+ return true;
+}
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