1 files changed, 333 insertions, 0 deletions
diff --git a/drivers/misc/bcm-vk/bcm_vk_tty.c b/drivers/misc/bcm-vk/bcm_vk_tty.c
new file mode 100644
index 000000000000..be3964949b63
--- /dev/null
+++ b/drivers/misc/bcm-vk/bcm_vk_tty.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018-2020 Broadcom.
+ */
+
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+
+#include "bcm_vk.h"
+
+/* TTYVK base offset is 0x30000 into BAR1 */
+#define BAR1_TTYVK_BASE_OFFSET	0x300000
+/* Each TTYVK channel (TO or FROM) is 0x10000 */
+#define BAR1_TTYVK_CHAN_OFFSET	0x100000
+/* Each TTYVK channel has TO and FROM, hence the * 2 */
+#define BAR1_TTYVK_BASE(index)	(BAR1_TTYVK_BASE_OFFSET + \
+				 ((index) * BAR1_TTYVK_CHAN_OFFSET * 2))
+/* TO TTYVK channel base comes before FROM for each index */
+#define TO_TTYK_BASE(index)	BAR1_TTYVK_BASE(index)
+#define FROM_TTYK_BASE(index)	(BAR1_TTYVK_BASE(index) + \
+				 BAR1_TTYVK_CHAN_OFFSET)
+
+struct bcm_vk_tty_chan {
+	u32 reserved;
+	u32 size;
+	u32 wr;
+	u32 rd;
+	u32 *data;
+};
+
+#define VK_BAR_CHAN(v, DIR, e)	((v)->DIR##_offset \
+				 + offsetof(struct bcm_vk_tty_chan, e))
+#define VK_BAR_CHAN_SIZE(v, DIR)	VK_BAR_CHAN(v, DIR, size)
+#define VK_BAR_CHAN_WR(v, DIR)		VK_BAR_CHAN(v, DIR, wr)
+#define VK_BAR_CHAN_RD(v, DIR)		VK_BAR_CHAN(v, DIR, rd)
+#define VK_BAR_CHAN_DATA(v, DIR, off)	(VK_BAR_CHAN(v, DIR, data) + (off))
+
+#define VK_BAR0_REGSEG_TTY_DB_OFFSET	0x86c
+
+/* Poll every 1/10 of second - temp hack till we use MSI interrupt */
+#define SERIAL_TIMER_VALUE (HZ / 10)
+
+static void bcm_vk_tty_poll(struct timer_list *t)
+{
+	struct bcm_vk *vk = from_timer(vk, t, serial_timer);
+
+	queue_work(vk->tty_wq_thread, &vk->tty_wq_work);
+	mod_timer(&vk->serial_timer, jiffies + SERIAL_TIMER_VALUE);
+}
+
+irqreturn_t bcm_vk_tty_irqhandler(int irq, void *dev_id)
+{
+	struct bcm_vk *vk = dev_id;
+
+	queue_work(vk->tty_wq_thread, &vk->tty_wq_work);
+
+	return IRQ_HANDLED;
+}
+
+static void bcm_vk_tty_wq_handler(struct work_struct *work)
+{
+	struct bcm_vk *vk = container_of(work, struct bcm_vk, tty_wq_work);
+	struct bcm_vk_tty *vktty;
+	int card_status;
+	int count;
+	unsigned char c;
+	int i;
+	int wr;
+
+	card_status = vkread32(vk, BAR_0, BAR_CARD_STATUS);
+	if (BCM_VK_INTF_IS_DOWN(card_status))
+		return;
+
+	for (i = 0; i < BCM_VK_NUM_TTY; i++) {
+		count = 0;
+		/* Check the card status that the tty channel is ready */
+		if ((card_status & BIT(i)) == 0)
+			continue;
+
+		vktty = &vk->tty[i];
+
+		/* Don't increment read index if tty app is closed */
+		if (!vktty->is_opened)
+			continue;
+
+		/* Fetch the wr offset in buffer from VK */
+		wr = vkread32(vk, BAR_1, VK_BAR_CHAN_WR(vktty, from));
+
+		/* safe to ignore until bar read gives proper size */
+		if (vktty->from_size == 0)
+			continue;
+
+		if (wr >= vktty->from_size) {
+			dev_err(&vk->pdev->dev,
+				"ERROR: wq handler ttyVK%d wr:0x%x > 0x%x\n",
+				i, wr, vktty->from_size);
+			/* Need to signal and close device in this case */
+			continue;
+		}
+
+		/*
+		 * Simple read of circular buffer and
+		 * insert into tty flip buffer
+		 */
+		while (vk->tty[i].rd != wr) {
+			c = vkread8(vk, BAR_1,
+				    VK_BAR_CHAN_DATA(vktty, from, vktty->rd));
+			vktty->rd++;
+			if (vktty->rd >= vktty->from_size)
+				vktty->rd = 0;
+			tty_insert_flip_char(&vktty->port, c, TTY_NORMAL);
+			count++;
+		}
+
+		if (count) {
+			tty_flip_buffer_push(&vktty->port);
+
+			/* Update read offset from shadow register to card */
+			vkwrite32(vk, vktty->rd, BAR_1,
+				  VK_BAR_CHAN_RD(vktty, from));
+		}
+	}
+}
+
+static int bcm_vk_tty_open(struct tty_struct *tty, struct file *file)
+{
+	int card_status;
+	struct bcm_vk *vk;
+	struct bcm_vk_tty *vktty;
+	int index;
+
+	/* initialize the pointer in case something fails */
+	tty->driver_data = NULL;
+
+	vk = (struct bcm_vk *)dev_get_drvdata(tty->dev);
+	index = tty->index;
+
+	if (index >= BCM_VK_NUM_TTY)
+		return -EINVAL;
+
+	vktty = &vk->tty[index];
+
+	vktty->pid = task_pid_nr(current);
+	vktty->to_offset = TO_TTYK_BASE(index);
+	vktty->from_offset = FROM_TTYK_BASE(index);
+
+	/* Do not allow tty device to be opened if tty on card not ready */
+	card_status = vkread32(vk, BAR_0, BAR_CARD_STATUS);
+	if (BCM_VK_INTF_IS_DOWN(card_status) || ((card_status & BIT(index)) == 0))
+		return -EBUSY;
+
+	/*
+	 * Get shadow registers of the buffer sizes and the "to" write offset
+	 * and "from" read offset
+	 */
+	vktty->to_size = vkread32(vk, BAR_1, VK_BAR_CHAN_SIZE(vktty, to));
+	vktty->wr = vkread32(vk, BAR_1,  VK_BAR_CHAN_WR(vktty, to));
+	vktty->from_size = vkread32(vk, BAR_1, VK_BAR_CHAN_SIZE(vktty, from));
+	vktty->rd = vkread32(vk, BAR_1,  VK_BAR_CHAN_RD(vktty, from));
+	vktty->is_opened = true;
+
+	if (tty->count == 1 && !vktty->irq_enabled) {
+		timer_setup(&vk->serial_timer, bcm_vk_tty_poll, 0);
+		mod_timer(&vk->serial_timer, jiffies + SERIAL_TIMER_VALUE);
+	}
+	return 0;
+}
+
+static void bcm_vk_tty_close(struct tty_struct *tty, struct file *file)
+{
+	struct bcm_vk *vk = dev_get_drvdata(tty->dev);
+
+	if (tty->index >= BCM_VK_NUM_TTY)
+		return;
+
+	vk->tty[tty->index].is_opened = false;
+
+	if (tty->count == 1)
+		del_timer_sync(&vk->serial_timer);
+}
+
+static void bcm_vk_tty_doorbell(struct bcm_vk *vk, u32 db_val)
+{
+	vkwrite32(vk, db_val, BAR_0,
+		  VK_BAR0_REGSEG_DB_BASE + VK_BAR0_REGSEG_TTY_DB_OFFSET);
+}
+
+static int bcm_vk_tty_write(struct tty_struct *tty,
+			    const unsigned char *buffer,
+			    int count)
+{
+	int index;
+	struct bcm_vk *vk;
+	struct bcm_vk_tty *vktty;
+	int i;
+
+	index = tty->index;
+	vk = dev_get_drvdata(tty->dev);
+	vktty = &vk->tty[index];
+
+	/* Simple write each byte to circular buffer */
+	for (i = 0; i < count; i++) {
+		vkwrite8(vk, buffer[i], BAR_1,
+			 VK_BAR_CHAN_DATA(vktty, to, vktty->wr));
+		vktty->wr++;
+		if (vktty->wr >= vktty->to_size)
+			vktty->wr = 0;
+	}
+	/* Update write offset from shadow register to card */
+	vkwrite32(vk, vktty->wr, BAR_1, VK_BAR_CHAN_WR(vktty, to));
+	bcm_vk_tty_doorbell(vk, 0);
+
+	return count;
+}
+
+static int bcm_vk_tty_write_room(struct tty_struct *tty)
+{
+	struct bcm_vk *vk = dev_get_drvdata(tty->dev);
+
+	return vk->tty[tty->index].to_size - 1;
+}
+
+static const struct tty_operations serial_ops = {
+	.open = bcm_vk_tty_open,
+	.close = bcm_vk_tty_close,
+	.write = bcm_vk_tty_write,
+	.write_room = bcm_vk_tty_write_room,
+};
+
+int bcm_vk_tty_init(struct bcm_vk *vk, char *name)
+{
+	int i;
+	int err;
+	struct tty_driver *tty_drv;
+	struct device *dev = &vk->pdev->dev;
+
+	tty_drv = tty_alloc_driver
+				(BCM_VK_NUM_TTY,
+				 TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV);
+	if (IS_ERR(tty_drv))
+		return PTR_ERR(tty_drv);
+
+	/* Save struct tty_driver for uninstalling the device */
+	vk->tty_drv = tty_drv;
+
+	/* initialize the tty driver */
+	tty_drv->driver_name = KBUILD_MODNAME;
+	tty_drv->name = kstrdup(name, GFP_KERNEL);
+	if (!tty_drv->name) {
+		err = -ENOMEM;
+		goto err_put_tty_driver;
+	}
+	tty_drv->type = TTY_DRIVER_TYPE_SERIAL;
+	tty_drv->subtype = SERIAL_TYPE_NORMAL;
+	tty_drv->init_termios = tty_std_termios;
+	tty_set_operations(tty_drv, &serial_ops);
+
+	/* register the tty driver */
+	err = tty_register_driver(tty_drv);
+	if (err) {
+		dev_err(dev, "tty_register_driver failed\n");
+		goto err_kfree_tty_name;
+	}
+
+	for (i = 0; i < BCM_VK_NUM_TTY; i++) {
+		struct device *tty_dev;
+
+		tty_port_init(&vk->tty[i].port);
+		tty_dev = tty_port_register_device(&vk->tty[i].port, tty_drv,
+						   i, dev);
+		if (IS_ERR(tty_dev)) {
+			err = PTR_ERR(tty_dev);
+			goto unwind;
+		}
+		dev_set_drvdata(tty_dev, vk);
+		vk->tty[i].is_opened = false;
+	}
+
+	INIT_WORK(&vk->tty_wq_work, bcm_vk_tty_wq_handler);
+	vk->tty_wq_thread = create_singlethread_workqueue("tty");
+	if (!vk->tty_wq_thread) {
+		dev_err(dev, "Fail to create tty workqueue thread\n");
+		err = -ENOMEM;
+		goto unwind;
+	}
+	return 0;
+
+unwind:
+	while (--i >= 0)
+		tty_port_unregister_device(&vk->tty[i].port, tty_drv, i);
+	tty_unregister_driver(tty_drv);
+
+err_kfree_tty_name:
+	kfree(tty_drv->name);
+	tty_drv->name = NULL;
+
+err_put_tty_driver:
+	put_tty_driver(tty_drv);
+
+	return err;
+}
+
+void bcm_vk_tty_exit(struct bcm_vk *vk)
+{
+	int i;
+
+	del_timer_sync(&vk->serial_timer);
+	for (i = 0; i < BCM_VK_NUM_TTY; ++i) {
+		tty_port_unregister_device(&vk->tty[i].port,
+					   vk->tty_drv,
+					   i);
+		tty_port_destroy(&vk->tty[i].port);
+	}
+	tty_unregister_driver(vk->tty_drv);
+
+	kfree(vk->tty_drv->name);
+	vk->tty_drv->name = NULL;
+
+	put_tty_driver(vk->tty_drv);
+}
+
+void bcm_vk_tty_terminate_tty_user(struct bcm_vk *vk)
+{
+	struct bcm_vk_tty *vktty;
+	int i;
+
+	for (i = 0; i < BCM_VK_NUM_TTY; ++i) {
+		vktty = &vk->tty[i];
+		if (vktty->pid)
+			kill_pid(find_vpid(vktty->pid), SIGKILL, 1);
+	}
+}