Motorola is using a custom TS 27.010 based serial port line discipline for various devices on the modem. These devices can be accessed on dedicated channels using Linux kernel serdev-ngsm driver. For the GNSS on these devices, we need to kick the GNSS device at a desired rate. Otherwise the GNSS device stops sending data after a few minutes. The rate we poll data defaults to 1000 ms, and can be specified with a module option rate_ms between 1 to 16 seconds. [Tony Lindgren did most of the work here, I just converted it to be normal serdev.] Signed-off-by: Pavel Machek diff --git a/drivers/gnss/Kconfig b/drivers/gnss/Kconfig index bd12e3d57baa..a7c449d8428c 100644 --- a/drivers/gnss/Kconfig +++ b/drivers/gnss/Kconfig @@ -13,6 +13,14 @@ menuconfig GNSS if GNSS +config GNSS_MOTMDM + tristate "Motorola Modem TS 27.010 serdev GNSS receiver support" + depends on SERIAL_DEV_N_GSM + help + Say Y here if you have a Motorola modem using TS 27.010 line + discipline for GNSS such as a Motorola Mapphone series device + like Droid 4. + config GNSS_SERIAL tristate diff --git a/drivers/gnss/Makefile b/drivers/gnss/Makefile index 451f11401ecc..f5afc2c22a3b 100644 --- a/drivers/gnss/Makefile +++ b/drivers/gnss/Makefile @@ -6,6 +6,9 @@ obj-$(CONFIG_GNSS) += gnss.o gnss-y := core.o +obj-$(CONFIG_GNSS_MOTMDM) += gnss-motmdm.o +gnss-motmdm-y := motmdm.o + obj-$(CONFIG_GNSS_SERIAL) += gnss-serial.o gnss-serial-y := serial.o diff --git a/drivers/gnss/motmdm.c b/drivers/gnss/motmdm.c new file mode 100644 index 000000000000..bfd50e130631 --- /dev/null +++ b/drivers/gnss/motmdm.c @@ -0,0 +1,409 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Motorola Modem TS 27.010 serdev GNSS driver + * + * Copyright (C) 2018 - 2020 Tony Lindgren + * Copyright (C) 2020 - 2021 Pavel Machek + * + * Based on drivers/gnss/sirf.c driver example: + * Copyright (C) 2018 Johan Hovold + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define MOTMDM_GNSS_TIMEOUT 1000 +#define MOTMDM_GNSS_RATE 1000 + +/* + * Motorola MDM GNSS device communicates over a dedicated TS 27.010 channel + * using custom data packets. The packets look like AT commands embedded into + * a Motorola invented packet using format like "U1234AT+MPDSTART=0,1,100,0". + * But it's not an AT compatible serial interface, it's a packet interface + * using AT like commands. + */ +#define MOTMDM_GNSS_HEADER_LEN 5 /* U1234 */ +#define MOTMDM_GNSS_RESP_LEN (MOTMDM_GNSS_HEADER_LEN + 4) /* U1234+MPD */ +#define MOTMDM_GNSS_DATA_LEN (MOTMDM_GNSS_RESP_LEN + 1) /* U1234~+MPD */ +#define MOTMDM_GNSS_STATUS_LEN (MOTMDM_GNSS_DATA_LEN + 7) /* STATUS= */ +#define MOTMDM_GNSS_NMEA_LEN (MOTMDM_GNSS_DATA_LEN + 8) /* NMEA=NN, */ + +enum motmdm_gnss_status { + MOTMDM_GNSS_UNKNOWN, + MOTMDM_GNSS_INITIALIZED, + MOTMDM_GNSS_DATA_OR_TIMEOUT, + MOTMDM_GNSS_STARTED, + MOTMDM_GNSS_STOPPED, +}; + +struct motmdm_gnss_data { + struct gnss_device *gdev; + struct device *modem; + struct serdev_device *serdev; + struct delayed_work restart_work; + struct mutex mutex; /* For modem commands */ + ktime_t last_update; + int status; + unsigned char *buf; + size_t len; + wait_queue_head_t read_queue; + unsigned int parsed:1; +}; + +static unsigned int rate_ms = MOTMDM_GNSS_RATE; +module_param(rate_ms, uint, 0644); +MODULE_PARM_DESC(rate_ms, "GNSS refresh rate between 1000 and 16000 ms (default 1000 ms)"); + +/* + * Note that multiple commands can be sent in series with responses coming + * out-of-order. For GNSS, we don't need to care about the out-of-order + * responses, and can assume we have at most one command active at a time. + * For the commands, can use just a jiffies base packet ID and let the modem + * sort out the ID conflicts with the modem's unsolicited message ID + * numbering. + */ +int motmdm_gnss_send_command(struct motmdm_gnss_data *ddata, + const u8 *buf, int len) +{ + struct gnss_device *gdev = ddata->gdev; + const int timeout_ms = 1000; + unsigned char cmd[128]; + int ret, cmdlen; + + cmdlen = len + MOTMDM_GNSS_HEADER_LEN + 1; + if (cmdlen > 128) + return -EINVAL; + + mutex_lock(&ddata->mutex); + memset(ddata->buf, 0, ddata->len); + ddata->parsed = false; + snprintf(cmd, cmdlen, "U%04li%s", jiffies % 10000, buf); + + ret = serdev_device_write(ddata->serdev, cmd, cmdlen, MAX_SCHEDULE_TIMEOUT); + if (ret < 0) + goto out_unlock; + + serdev_device_wait_until_sent(ddata->serdev, 0); + + ret = wait_event_timeout(ddata->read_queue, ddata->parsed, + msecs_to_jiffies(timeout_ms)); + if (ret == 0) { + ret = -ETIMEDOUT; + goto out_unlock; + } else if (ret < 0) { + goto out_unlock; + } + + if (!strstr(ddata->buf, ":OK")) { + dev_err(&gdev->dev, "command %s error %s\n", + cmd, ddata->buf); + ret = -EPIPE; + } + + ret = len; + +out_unlock: + mutex_unlock(&ddata->mutex); + + return ret; +} + +/* + * Android uses AT+MPDSTART=0,1,100,0 which starts GNSS for a while, + * and then GNSS needs to be kicked with an AT command based on a + * status message. + */ +static void motmdm_gnss_restart(struct work_struct *work) +{ + struct motmdm_gnss_data *ddata = + container_of(work, struct motmdm_gnss_data, + restart_work.work); + struct gnss_device *gdev = ddata->gdev; + const unsigned char *cmd = "AT+MPDSTART=0,1,100,0"; + int error; + + ddata->last_update = ktime_get(); + + error = motmdm_gnss_send_command(ddata, cmd, strlen(cmd)); + if (error < 0) { + /* Timeouts can happen, don't warn and try again */ + if (error != -ETIMEDOUT) + dev_warn(&gdev->dev, "%s: could not start: %i\n", + __func__, error); + + schedule_delayed_work(&ddata->restart_work, + msecs_to_jiffies(MOTMDM_GNSS_RATE)); + } +} + +static void motmdm_gnss_start(struct gnss_device *gdev, int delay_ms) +{ + struct motmdm_gnss_data *ddata = gnss_get_drvdata(gdev); + ktime_t now, next, delta; + int next_ms; + + now = ktime_get(); + next = ktime_add_ms(ddata->last_update, delay_ms); + delta = ktime_sub(next, now); + next_ms = ktime_to_ms(delta); + + if (next_ms < 0) + next_ms = 0; + if (next_ms > delay_ms) + next_ms = delay_ms; + + schedule_delayed_work(&ddata->restart_work, msecs_to_jiffies(next_ms)); +} + +static int motmdm_gnss_stop(struct gnss_device *gdev) +{ + struct motmdm_gnss_data *ddata = gnss_get_drvdata(gdev); + const unsigned char *cmd = "AT+MPDSTOP"; + + cancel_delayed_work_sync(&ddata->restart_work); + + return motmdm_gnss_send_command(ddata, cmd, strlen(cmd)); +} + +static int motmdm_gnss_init(struct gnss_device *gdev) +{ + struct motmdm_gnss_data *ddata = gnss_get_drvdata(gdev); + const unsigned char *cmd = "AT+MPDINIT=1"; + int error; + + error = motmdm_gnss_send_command(ddata, cmd, strlen(cmd)); + if (error < 0) + return error; + + motmdm_gnss_start(gdev, 0); + + return 0; +} + +static int motmdm_gnss_finish(struct gnss_device *gdev) +{ + struct motmdm_gnss_data *ddata = gnss_get_drvdata(gdev); + const unsigned char *cmd = "AT+MPDINIT=0"; + int error; + + error = motmdm_gnss_stop(gdev); + if (error < 0) + return error; + + return motmdm_gnss_send_command(ddata, cmd, strlen(cmd)); +} + +static int motmdm_gnss_receive_data(struct serdev_device *serdev, + const unsigned char *buf, size_t len) +{ + struct motmdm_gnss_data *ddata = serdev_device_get_drvdata(serdev); + struct gnss_device *gdev = ddata->gdev; + const unsigned char *msg; + size_t msglen; + int error = 0; + + if (len <= MOTMDM_GNSS_RESP_LEN) + return 0; + + /* Handle U1234+MPD style command response */ + if (buf[MOTMDM_GNSS_HEADER_LEN] != '~') { + msg = buf + MOTMDM_GNSS_RESP_LEN; + strncpy(ddata->buf, msg, len - MOTMDM_GNSS_RESP_LEN); + ddata->parsed = true; + wake_up(&ddata->read_queue); + + return len; + } + + if (len <= MOTMDM_GNSS_DATA_LEN) + return 0; + + /* Handle U1234~+MPD style unsolicted message */ + switch (buf[MOTMDM_GNSS_DATA_LEN]) { + case 'N': /* UNNNN~+MPDNMEA=NN, */ + msg = buf + MOTMDM_GNSS_NMEA_LEN; + msglen = len - MOTMDM_GNSS_NMEA_LEN; + + /* + * Firmware bug: Strip out extra duplicate line break always + * in the data + */ + msglen--; + + /* + * Firmware bug: Strip out extra data based on an + * earlier line break in the data + */ + if (msg[msglen - 5 - 1] == 0x0a) + msglen -= 5; + + error = gnss_insert_raw(gdev, msg, msglen); + WARN_ON(error); + break; + case 'S': /* UNNNN~+MPDSTATUS=N,NN */ + msg = buf + MOTMDM_GNSS_STATUS_LEN; + msglen = len - MOTMDM_GNSS_STATUS_LEN; + + switch (msg[0]) { + case '1': + ddata->status = MOTMDM_GNSS_INITIALIZED; + break; + case '2': + ddata->status = MOTMDM_GNSS_DATA_OR_TIMEOUT; + if (rate_ms < MOTMDM_GNSS_RATE) + rate_ms = MOTMDM_GNSS_RATE; + if (rate_ms > 16 * MOTMDM_GNSS_RATE) + rate_ms = 16 * MOTMDM_GNSS_RATE; + motmdm_gnss_start(gdev, rate_ms); + break; + case '3': + ddata->status = MOTMDM_GNSS_STARTED; + break; + case '4': + ddata->status = MOTMDM_GNSS_STOPPED; + break; + default: + ddata->status = MOTMDM_GNSS_UNKNOWN; + break; + } + break; + case 'X': /* UNNNN~+MPDXREQ=N for updated xtra2.bin needed */ + default: + break; + } + + return len; +} + +static const struct serdev_device_ops gnss_serdev_ops = { + .receive_buf = motmdm_gnss_receive_data, + .write_wakeup = serdev_device_write_wakeup, +}; + +static int motmdm_gnss_open(struct gnss_device *gdev) +{ + struct motmdm_gnss_data *ddata = gnss_get_drvdata(gdev); + int error; + + serdev_device_set_client_ops(ddata->serdev, &gnss_serdev_ops); + + error = serdev_device_open(ddata->serdev); + if (error) { + return error; + } + + error = motmdm_gnss_init(gdev); + if (error) { + return error; + } + + return 0; +} + +static void motmdm_gnss_close(struct gnss_device *gdev) +{ + struct motmdm_gnss_data *ddata = gnss_get_drvdata(gdev); + int error; + + error = motmdm_gnss_finish(gdev); + if (error < 0) + dev_warn(&gdev->dev, "%s: close failed: %i\n", + __func__, error); + + serdev_device_close(ddata->serdev); +} + +static int motmdm_gnss_write_raw(struct gnss_device *gdev, + const unsigned char *buf, + size_t count) +{ + struct motmdm_gnss_data *ddata = gnss_get_drvdata(gdev); + + return serdev_device_write(ddata->serdev, buf, count, MAX_SCHEDULE_TIMEOUT); + serdev_device_wait_until_sent(ddata->serdev, 0); + + return count; +} + +static const struct gnss_operations motmdm_gnss_ops = { + .open = motmdm_gnss_open, + .close = motmdm_gnss_close, + .write_raw = motmdm_gnss_write_raw, +}; + +static int motmdm_gnss_probe(struct serdev_device *serdev) +{ + struct device *dev = &serdev->dev; + struct motmdm_gnss_data *ddata; + struct gnss_device *gdev; + int ret; + + ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); + if (!ddata) + return -ENOMEM; + + ddata->serdev = serdev; + ddata->modem = dev->parent; + ddata->len = PAGE_SIZE; + mutex_init(&ddata->mutex); + INIT_DELAYED_WORK(&ddata->restart_work, motmdm_gnss_restart); + init_waitqueue_head(&ddata->read_queue); + + ddata->buf = devm_kzalloc(dev, ddata->len, GFP_KERNEL); + if (!ddata->buf) + return -ENOMEM; + + serdev_device_set_drvdata(serdev, ddata); + + gdev = gnss_allocate_device(dev); + if (!gdev) + return -ENOMEM; + + gdev->type = GNSS_TYPE_NMEA; + gdev->ops = &motmdm_gnss_ops; + gnss_set_drvdata(gdev, ddata); + ddata->gdev = gdev; + + ret = gnss_register_device(gdev); + if (ret) + gnss_put_device(ddata->gdev); + + return ret; +} + +static void motmdm_gnss_remove(struct serdev_device *serdev) +{ + struct motmdm_gnss_data *data = serdev_device_get_drvdata(serdev); + + gnss_deregister_device(data->gdev); + gnss_put_device(data->gdev); +}; + +#ifdef CONFIG_OF +static const struct of_device_id motmdm_gnss_of_match[] = { + { .compatible = "motorola,mapphone-mdm6600-gnss" }, + {}, +}; +MODULE_DEVICE_TABLE(of, motmdm_gnss_of_match); +#endif + +static struct serdev_device_driver motmdm_gnss_driver = { + .driver = { + .name = "gnss-mot-mdm6600", + .of_match_table = of_match_ptr(motmdm_gnss_of_match), + }, + .probe = motmdm_gnss_probe, + .remove = motmdm_gnss_remove, +}; +module_serdev_device_driver(motmdm_gnss_driver); + +MODULE_AUTHOR("Tony Lindgren "); +MODULE_DESCRIPTION("Motorola Mapphone MDM6600 GNSS receiver driver"); +MODULE_LICENSE("GPL v2"); -- http://www.livejournal.com/~pavelmachek