[PATCH v4 06/16] misc: bcm-vk: add ttyVK support

Scott Branden
2020-09-29T00:12:57Z

Add ttyVK support to driver to allow console access to VK card from host.

Device node will be in the follow form /dev/bcm-vk.x_ttyVKy where:
x is the instance of the VK card
y is the tty device number on the VK card

Signed-off-by: Scott Branden <scott.branden@broadcom.com>
---
drivers/misc/bcm-vk/Makefile | 4 +-
drivers/misc/bcm-vk/bcm_vk.h | 27 +++
drivers/misc/bcm-vk/bcm_vk_dev.c | 14 +-
drivers/misc/bcm-vk/bcm_vk_tty.c | 336 +++++++++++++++++++++++++++++++
4 files changed, 379 insertions(+), 2 deletions(-)
create mode 100644 drivers/misc/bcm-vk/bcm_vk_tty.c

diff --git a/drivers/misc/bcm-vk/Makefile b/drivers/misc/bcm-vk/Makefile
index f8a7ac4c242f..e50aa3ca31e9 100644
--- a/drivers/misc/bcm-vk/Makefile
+++ b/drivers/misc/bcm-vk/Makefile
@@ -5,4 +5,6 @@

obj-$(CONFIG_BCM_VK) += bcm_vk.o
bcm_vk-objs := \
- bcm_vk_dev.o
+ bcm_vk_dev.o \
+ bcm_vk_tty.o
+
diff --git a/drivers/misc/bcm-vk/bcm_vk.h b/drivers/misc/bcm-vk/bcm_vk.h
index f428ad9a0c3d..b1408daa7261 100644
--- a/drivers/misc/bcm-vk/bcm_vk.h
+++ b/drivers/misc/bcm-vk/bcm_vk.h
@@ -10,6 +10,8 @@
#include <linux/miscdevice.h>
#include <linux/pci.h>
#include <linux/sched/signal.h>
+#include <linux/tty.h>
+#include <uapi/linux/misc/bcm_vk.h>

#define DRV_MODULE_NAME "bcm-vk"

@@ -76,6 +78,9 @@
#define CODEPUSH_BOOT2_ENTRY 0x60000000

#define BAR_CARD_STATUS 0x410
+/* CARD_STATUS definitions */
+#define CARD_STATUS_TTYVK0_READY BIT(0)
+#define CARD_STATUS_TTYVK1_READY BIT(1)

#define BAR_BOOT1_STDALONE_PROGRESS 0x420
#define BOOT1_STDALONE_SUCCESS (BIT(13) | BIT(14))
@@ -199,6 +204,19 @@ enum pci_barno {

#define BCM_VK_NUM_TTY 2

+struct bcm_vk_tty {
+ struct tty_port port;
+ u32 to_offset; /* bar offset to use */
+ u32 to_size; /* to VK buffer size */
+ u32 wr; /* write offset shadow */
+ u32 from_offset; /* bar offset to use */
+ u32 from_size; /* from VK buffer size */
+ u32 rd; /* read offset shadow */
+ pid_t pid;
+ bool irq_enabled;
+ bool is_opened; /* tracks tty open/close */
+};
+
/* DAUTH related info */
struct bcm_vk_dauth_key {
char store[VK_BAR1_DAUTH_STORE_SIZE];
@@ -218,6 +236,12 @@ struct bcm_vk {
struct miscdevice miscdev;
int devid; /* dev id allocated */

+ struct tty_driver *tty_drv;
+ struct timer_list serial_timer;
+ struct bcm_vk_tty tty[BCM_VK_NUM_TTY];
+ struct workqueue_struct *tty_wq_thread;
+ struct work_struct tty_wq_work;
+
struct workqueue_struct *wq_thread;
struct work_struct wq_work; /* work queue for deferred job */
unsigned long wq_offload[1]; /* various flags on wq requested */
@@ -279,5 +303,8 @@ static inline bool bcm_vk_msgq_marker_valid(struct bcm_vk *vk)
}

int bcm_vk_auto_load_all_images(struct bcm_vk *vk);
+int bcm_vk_tty_init(struct bcm_vk *vk, char *name);
+void bcm_vk_tty_exit(struct bcm_vk *vk);
+void bcm_vk_tty_terminate_tty_user(struct bcm_vk *vk);

#endif
diff --git a/drivers/misc/bcm-vk/bcm_vk_dev.c b/drivers/misc/bcm-vk/bcm_vk_dev.c
index 0782e2cff36d..dfef9546c5a7 100644
--- a/drivers/misc/bcm-vk/bcm_vk_dev.c
+++ b/drivers/misc/bcm-vk/bcm_vk_dev.c
@@ -761,6 +761,11 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
goto err_destroy_workqueue;
}

+ snprintf(name, sizeof(name), KBUILD_MODNAME ".%d_ttyVK", id);
+ err = bcm_vk_tty_init(vk, name);
+ if (err)
+ goto err_unregister_panic_notifier;
+
/*
* lets trigger an auto download. We don't want to do it serially here
* because at probing time, it is not supposed to block for a long time.
@@ -769,7 +774,7 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
if (auto_load) {
if ((boot_status & BOOT_STATE_MASK) == BROM_RUNNING) {
if (bcm_vk_trigger_autoload(vk))
- goto err_unregister_panic_notifier;
+ goto err_bcm_vk_tty_exit;
} else {
dev_err(dev,
"Auto-load skipped - BROM not in proper state (0x%x)\n",
@@ -781,6 +786,9 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

return 0;

+err_bcm_vk_tty_exit:
+ bcm_vk_tty_exit(vk);
+
err_unregister_panic_notifier:
atomic_notifier_chain_unregister(&panic_notifier_list,
&vk->panic_nb);
@@ -836,6 +844,8 @@ static void bcm_vk_remove(struct pci_dev *pdev)
atomic_notifier_chain_unregister(&panic_notifier_list,
&vk->panic_nb);

+ bcm_vk_tty_exit(vk);
+
if (vk->tdma_vaddr)
dma_free_coherent(&pdev->dev, nr_scratch_pages * PAGE_SIZE,
vk->tdma_vaddr, vk->tdma_addr);
@@ -849,6 +859,8 @@ static void bcm_vk_remove(struct pci_dev *pdev)

cancel_work_sync(&vk->wq_work);
destroy_workqueue(vk->wq_thread);
+ cancel_work_sync(&vk->tty_wq_work);
+ destroy_workqueue(vk->tty_wq_thread);

for (i = 0; i < MAX_BAR; i++) {
if (vk->bar[i])
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..7f71d1f9085b
--- /dev/null
+++ b/drivers/misc/bcm-vk/bcm_vk_tty.c
@@ -0,0 +1,336 @@
+// 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 (card_status == -1)
+ 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 (card_status == -1)
+ return -1;
+
+ if ((card_status & BIT(index)) == 0)
+ return -1;
+
+ /*
+ * 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);
+ }
+}
--
2.17.1