[Intel-wired-lan] [PATCH intel-next 3/3] ice: add write functionality for GNSS TTY

Karol Kolacinski karol.kolacinski at intel.com
Fri Apr 15 10:31:39 UTC 2022


Add the possibility to write raw bytes to the GNSS module through the
first TTY device. This allow user to configure the module.

Create a second read-only TTY device.

Signed-off-by: Karol Kolacinski <karol.kolacinski at intel.com>
---
 drivers/net/ethernet/intel/ice/ice.h      |   4 +-
 drivers/net/ethernet/intel/ice/ice_gnss.c | 230 +++++++++++++++++++---
 drivers/net/ethernet/intel/ice/ice_gnss.h |  23 ++-
 3 files changed, 231 insertions(+), 26 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index 17fb1ddea7b0..41bd0c7c7da5 100644
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -558,8 +558,8 @@ struct ice_pf {
 	u32 msg_enable;
 	struct ice_ptp ptp;
 	struct tty_driver *ice_gnss_tty_driver;
-	struct tty_port gnss_tty_port;
-	struct gnss_serial *gnss_serial;
+	struct tty_port *gnss_tty_port[ICE_GNSS_TTY_MINOR_DEVICES];
+	struct gnss_serial *gnss_serial[ICE_GNSS_TTY_MINOR_DEVICES];
 	u16 num_rdma_msix;		/* Total MSIX vectors for RDMA driver */
 	u16 rdma_base_vector;
 
diff --git a/drivers/net/ethernet/intel/ice/ice_gnss.c b/drivers/net/ethernet/intel/ice/ice_gnss.c
index f0b2091c3b5f..eafebd873236 100644
--- a/drivers/net/ethernet/intel/ice/ice_gnss.c
+++ b/drivers/net/ethernet/intel/ice/ice_gnss.c
@@ -5,6 +5,99 @@
 #include "ice_lib.h"
 #include <linux/tty_driver.h>
 
+/**
+ * ice_gnss_do_write - Write data to internal GNSS
+ * @pf: board private structure
+ * @buf: command buffer
+ * @size: command buffer size
+ *
+ * Write UBX command data to the GNSS receiver
+ */
+static void ice_gnss_do_write(struct ice_pf *pf, u8 *buf, u32 size)
+{
+	u32 i, num_writes, part_writes_num, last_write_bytes, offset = 0;
+	struct ice_aqc_link_topo_addr link_topo;
+	struct ice_hw *hw = &pf->hw;
+	int err = 0;
+
+	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 |=
+		ICE_AQC_LINK_TOPO_NODE_CTX_OVERRIDE <<
+		ICE_AQC_LINK_TOPO_NODE_CTX_S;
+
+	/* Write all bytes except the last partial write */
+	last_write_bytes = size % ICE_GNSS_UBX_WRITE_BYTES;
+	if (last_write_bytes == 0)
+		part_writes_num = 0;
+	else if (last_write_bytes == 1)
+		part_writes_num = 2;
+	else
+		part_writes_num = 1;
+
+	num_writes = size / ICE_GNSS_UBX_WRITE_BYTES - part_writes_num;
+
+	for (i = 0; i < num_writes; i++) {
+		err = ice_aq_write_i2c(hw, link_topo, ICE_GNSS_UBX_I2C_BUS_ADDR,
+				       cpu_to_le16(buf[offset]),
+				       ICE_MAX_I2C_WRITE_BYTES,
+				       &buf[offset + 1], NULL);
+		if (err)
+			goto err;
+
+		offset += ICE_GNSS_UBX_WRITE_BYTES;
+	}
+
+	if (part_writes_num == 2) {
+		/* We cannot write a single byte to ublox. Do 2 last writes
+		 * instead of 1.
+		 */
+		err = ice_aq_write_i2c(hw, link_topo, ICE_GNSS_UBX_I2C_BUS_ADDR,
+				       cpu_to_le16(buf[offset]),
+				       ICE_MAX_I2C_WRITE_BYTES - 1,
+				       &buf[offset + 1], NULL);
+		if (err)
+			goto err;
+
+		offset += ICE_GNSS_UBX_WRITE_BYTES - 1;
+		last_write_bytes = 2;
+	}
+
+	if (part_writes_num)
+		err = ice_aq_write_i2c(hw, link_topo, ICE_GNSS_UBX_I2C_BUS_ADDR,
+				       cpu_to_le16(buf[offset]),
+				       last_write_bytes - 1, &buf[offset + 1],
+				       NULL);
+
+err:
+	if (err)
+		dev_err(ice_pf_to_dev(pf), "GNSS failed to write err=%d\n",
+			err);
+}
+
+/**
+ * ice_gnss_write_pending - Write all pending data to internal GNSS
+ * @work: GNSS write work structure
+ */
+static void ice_gnss_write_pending(struct kthread_work *work)
+{
+	struct gnss_serial *gnss = container_of(work, struct gnss_serial,
+						write_work);
+	struct ice_pf *pf = gnss->back;
+
+	if (!list_empty(&gnss->queue)) {
+		struct gnss_write_buf *write_buf = NULL;
+
+		write_buf = list_first_entry(&gnss->queue,
+					     struct gnss_write_buf, queue);
+		list_del(&write_buf->queue);
+
+		ice_gnss_do_write(pf, write_buf->buf, write_buf->size);
+		kfree(write_buf->buf);
+		kfree(write_buf);
+	}
+}
+
 /**
  * ice_gnss_read - Read data from internal GNSS module
  * @work: GNSS read work structure
@@ -103,8 +196,9 @@ static void ice_gnss_read(struct kthread_work *work)
 /**
  * ice_gnss_struct_init - Initialize GNSS structure for the TTY
  * @pf: Board private structure
+ * @index: TTY device index
  */
-static struct gnss_serial *ice_gnss_struct_init(struct ice_pf *pf)
+static struct gnss_serial *ice_gnss_struct_init(struct ice_pf *pf, int index)
 {
 	struct device *dev = ice_pf_to_dev(pf);
 	struct kthread_worker *kworker;
@@ -117,9 +211,11 @@ static struct gnss_serial *ice_gnss_struct_init(struct ice_pf *pf)
 	mutex_init(&gnss->gnss_mutex);
 	gnss->open_count = 0;
 	gnss->back = pf;
-	pf->gnss_serial = gnss;
+	pf->gnss_serial[index] = gnss;
 
 	kthread_init_delayed_work(&gnss->read_work, ice_gnss_read);
+	INIT_LIST_HEAD(&gnss->queue);
+	kthread_init_work(&gnss->write_work, ice_gnss_write_pending);
 	/* Allocate a kworker for handling work required for the GNSS TTY
 	 * writes.
 	 */
@@ -155,10 +251,10 @@ static int ice_gnss_tty_open(struct tty_struct *tty, struct file *filp)
 	tty->driver_data = NULL;
 
 	/* Get the serial object associated with this tty pointer */
-	gnss = pf->gnss_serial;
+	gnss = pf->gnss_serial[tty->index];
 	if (!gnss) {
 		/* Initialize GNSS struct on the first device open */
-		gnss = ice_gnss_struct_init(pf);
+		gnss = ice_gnss_struct_init(pf, tty->index);
 		if (!gnss)
 			return -ENOMEM;
 	}
@@ -211,25 +307,96 @@ static void ice_gnss_tty_close(struct tty_struct *tty, struct file *filp)
 }
 
 /**
- * ice_gnss_tty_write - Dummy TTY write function to avoid kernel panic
+ * ice_gnss_tty_write - Write GNSS data
  * @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)
+ *
+ * The write function call is called by the user when there is data to be sent
+ * to the hardware. First the tty core receives the call, and then it passes the
+ * data on to the tty driver’s write function. The tty core also tells the tty
+ * driver the size of the data being sent.
+ * If any errors happen during the write call, a negative error value should be
+ * returned instead of the number of characters that were written.
  */
 static int
 ice_gnss_tty_write(struct tty_struct *tty, const unsigned char *buf, int cnt)
 {
-	return 0;
+	struct gnss_write_buf *write_buf;
+	struct gnss_serial *gnss;
+	struct ice_pf *pf;
+	u8 *cmd_buf;
+
+	/* We cannot write a single byte using our I2C implementation. */
+	if (cnt <= 1 || cnt > ICE_GNSS_TTY_WRITE_BUF)
+		return -EINVAL;
+
+	gnss = tty->driver_data;
+	if (!gnss)
+		return -EFAULT;
+
+	pf = (struct ice_pf *)tty->driver->driver_state;
+	if (!pf)
+		return -EFAULT;
+
+	/* Allow write only on TTY 0 */
+	if (gnss != pf->gnss_serial[0])
+		return -EIO;
+
+	mutex_lock(&gnss->gnss_mutex);
+
+	if (!gnss->open_count) {
+		mutex_unlock(&gnss->gnss_mutex);
+		return -EINVAL;
+	}
+
+	cmd_buf = kzalloc(sizeof(*buf) * cnt, GFP_KERNEL);
+	if (!cmd_buf)
+		return -ENOMEM;
+
+	memcpy(cmd_buf, buf, cnt);
+
+	/* Send the data out to a hardware port */
+	write_buf = kzalloc(sizeof(*write_buf), GFP_KERNEL);
+	if (!write_buf)
+		return -ENOMEM;
+
+	write_buf->buf = cmd_buf;
+	write_buf->size = cnt;
+	INIT_LIST_HEAD(&write_buf->queue);
+	list_add_tail(&write_buf->queue, &gnss->queue);
+	kthread_queue_work(gnss->kworker, &gnss->write_work);
+	mutex_unlock(&gnss->gnss_mutex);
+	return cnt;
 }
 
 /**
- * ice_gnss_tty_write_room - Dummy TTY write_room function to avoid kernel panic
+ * ice_gnss_tty_write_room - Returns the numbers of characters to be written.
  * @tty: pointer to the tty_struct
+ *
+ * This routine returns the numbers of characters the tty driver will accept
+ * for queuing to be written. This number is subject to change as output buffers
+ * get emptied, or if the output flow control is acted.
  */
 static unsigned int ice_gnss_tty_write_room(struct tty_struct *tty)
 {
-	return 0;
+	struct gnss_serial *gnss = tty->driver_data;
+	unsigned int room = 0;
+
+	/* Allow write only on TTY 0 */
+	if (!gnss || gnss != gnss->back->gnss_serial[0])
+		return room;
+
+	mutex_lock(&gnss->gnss_mutex);
+
+	if (!gnss->open_count)
+		goto exit;
+
+	room = ICE_GNSS_TTY_WRITE_BUF;
+exit:
+	mutex_unlock(&gnss->gnss_mutex);
+	return room;
 }
 
 static const struct tty_operations tty_gps_ops = {
@@ -250,10 +417,12 @@ static struct tty_driver *ice_gnss_create_tty_driver(struct ice_pf *pf)
 	struct tty_driver *tty_driver;
 	char *ttydrv_name;
 	int err;
+	u32 i;
 
-	tty_driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW);
+	tty_driver = tty_alloc_driver(ICE_GNSS_TTY_MINOR_DEVICES,
+				      TTY_DRIVER_REAL_RAW);
 	if (IS_ERR(tty_driver)) {
-		dev_err(ice_pf_to_dev(pf), "Failed to allocate memory for GNSS TTY\n");
+		dev_err(dev, "Failed to allocate memory for GNSS TTY\n");
 		return NULL;
 	}
 
@@ -283,23 +452,32 @@ static struct tty_driver *ice_gnss_create_tty_driver(struct ice_pf *pf)
 	tty_driver->driver_state = pf;
 	tty_set_operations(tty_driver, &tty_gps_ops);
 
-	pf->gnss_serial = NULL;
+	for (i = 0; i < ICE_GNSS_TTY_MINOR_DEVICES; i++) {
+		pf->gnss_tty_port[i] = kzalloc(sizeof(*pf->gnss_tty_port[i]),
+					       GFP_KERNEL);
+		pf->gnss_serial[i] = NULL;
 
-	tty_port_init(&pf->gnss_tty_port);
-	tty_port_link_device(&pf->gnss_tty_port, tty_driver, 0);
+		tty_port_init(pf->gnss_tty_port[i]);
+		tty_port_link_device(pf->gnss_tty_port[i], tty_driver, i);
+	}
 
 	err = tty_register_driver(tty_driver);
 	if (err) {
-		dev_err(ice_pf_to_dev(pf), "Failed to register TTY driver err=%d\n",
-			err);
+		dev_err(dev, "Failed to register TTY driver err=%d\n", err);
 
-		tty_port_destroy(&pf->gnss_tty_port);
+		for (i = 0; i < ICE_GNSS_TTY_MINOR_DEVICES; i++) {
+			tty_port_destroy(pf->gnss_tty_port[i]);
+			kfree(pf->gnss_tty_port[i]);
+		}
 		kfree(ttydrv_name);
 		tty_driver_kref_put(pf->ice_gnss_tty_driver);
 
 		return NULL;
 	}
 
+	for (i = 0; i < ICE_GNSS_TTY_MINOR_DEVICES; i++)
+		dev_info(dev, "%s%d registered\n", ttydrv_name, i);
+
 	return tty_driver;
 }
 
@@ -327,17 +505,25 @@ void ice_gnss_init(struct ice_pf *pf)
  */
 void ice_gnss_exit(struct ice_pf *pf)
 {
+	u32 i;
+
 	if (!test_bit(ICE_FLAG_GNSS, pf->flags) || !pf->ice_gnss_tty_driver)
 		return;
 
-	tty_port_destroy(&pf->gnss_tty_port);
+	for (i = 0; i < ICE_GNSS_TTY_MINOR_DEVICES; i++) {
+		if (pf->gnss_tty_port[i]) {
+			tty_port_destroy(pf->gnss_tty_port[i]);
+			kfree(pf->gnss_tty_port[i]);
+		}
 
-	if (pf->gnss_serial) {
-		struct gnss_serial *gnss = pf->gnss_serial;
+		if (pf->gnss_serial[i]) {
+			struct gnss_serial *gnss = pf->gnss_serial[i];
 
-		kthread_cancel_delayed_work_sync(&gnss->read_work);
-		kfree(gnss);
-		pf->gnss_serial = NULL;
+			kthread_cancel_work_sync(&gnss->write_work);
+			kthread_cancel_delayed_work_sync(&gnss->read_work);
+			kfree(gnss);
+			pf->gnss_serial[i] = NULL;
+		}
 	}
 
 	tty_unregister_driver(pf->ice_gnss_tty_driver);
diff --git a/drivers/net/ethernet/intel/ice/ice_gnss.h b/drivers/net/ethernet/intel/ice/ice_gnss.h
index 9211adb2372c..59ba5749143e 100644
--- a/drivers/net/ethernet/intel/ice/ice_gnss.h
+++ b/drivers/net/ethernet/intel/ice/ice_gnss.h
@@ -8,14 +8,31 @@
 #include <linux/tty_flip.h>
 
 #define ICE_E810T_GNSS_I2C_BUS		0x2
+#define ICE_GNSS_TIMER_DELAY_TIME	(HZ / 10) /* 0.1 second per message */
+#define ICE_GNSS_TTY_MINOR_DEVICES	2
+#define ICE_GNSS_TTY_WRITE_BUF		250
+#define ICE_MAX_I2C_DATA_SIZE		FIELD_MAX(ICE_AQC_I2C_DATA_SIZE_M)
+#define ICE_MAX_I2C_WRITE_BYTES		4
+
+/* ublox specific deifinitions */
 #define ICE_GNSS_UBX_I2C_BUS_ADDR	0x42
 /* Data length register is big endian */
 #define ICE_GNSS_UBX_DATA_LEN_H		0xFD
 #define ICE_GNSS_UBX_DATA_LEN_WIDTH	2
 #define ICE_GNSS_UBX_EMPTY_DATA		0xFF
-#define ICE_GNSS_TIMER_DELAY_TIME	(HZ / 10) /* 0.1 second per message */
-#define ICE_MAX_I2C_DATA_SIZE		FIELD_MAX(ICE_AQC_I2C_DATA_SIZE_M)
+/* For ublox writes are performed without address so the first byte to write is
+ * passed as I2C addr parameter.
+ */
+#define ICE_GNSS_UBX_WRITE_BYTES	(ICE_MAX_I2C_WRITE_BYTES + 1)
 #define ICE_MAX_UBX_READ_TRIES		255
+#define ICE_MAX_UBX_ACK_READ_TRIES	4095
+
+struct gnss_write_buf {
+	struct list_head queue;
+	u32 size;
+	u8 *buf;
+};
+
 
 /**
  * struct gnss_serial - data used to initialize GNSS TTY port
@@ -33,6 +50,8 @@ struct gnss_serial {
 	struct mutex gnss_mutex; /* protects GNSS serial structure */
 	struct kthread_worker *kworker;
 	struct kthread_delayed_work read_work;
+	struct kthread_work write_work;
+	struct list_head queue;
 };
 
 #if IS_ENABLED(CONFIG_TTY)
-- 
2.34.1



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