Re: [PATCH 1/9] trinity: Add base driver

Greg KH
2022-07-27T13:22:53Z

On Mon, Jul 25, 2022 at 03:53:00PM +0900, Jiho Chu wrote:
> It contains the base codes for trinity driver. Minimal codes to load and
> probe device is provided. The Trinity Family is controlled by the
> Memory-Mapped Registers, the register addresses and offsets are
> described. And user api interfaces are presented to control device under
> ioctl manner.
>
> Signed-off-by: Jiho Chu <jiho.chu@samsung.com>
> Signed-off-by: yelini-jeong <yelini.jeong@samsung.com>
> Signed-off-by: Dongju Chae <dongju.chae@samsung.com>
> Signed-off-by: Parichay Kapoor <pk.kapoor@samsung.com>
> Signed-off-by: Wook Song <wook16.song@samsung.com>
> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
> ---
> drivers/misc/Kconfig | 1 +
> drivers/misc/Makefile | 1 +
> drivers/misc/trinity/Kconfig | 27 ++
> drivers/misc/trinity/Makefile | 7 +
> drivers/misc/trinity/trinity.c | 369 ++++++++++++++
> drivers/misc/trinity/trinity_common.h | 392 +++++++++++++++
> drivers/misc/trinity/trinity_vision2_drv.c | 512 ++++++++++++++++++++
> drivers/misc/trinity/trinity_vision2_regs.h | 210 ++++++++
> include/uapi/misc/trinity.h | 458 +++++++++++++++++
> 9 files changed, 1977 insertions(+)
> create mode 100644 drivers/misc/trinity/Kconfig
> create mode 100644 drivers/misc/trinity/Makefile
> create mode 100644 drivers/misc/trinity/trinity.c
> create mode 100644 drivers/misc/trinity/trinity_common.h
> create mode 100644 drivers/misc/trinity/trinity_vision2_drv.c
> create mode 100644 drivers/misc/trinity/trinity_vision2_regs.h
> create mode 100644 include/uapi/misc/trinity.h
>
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 41d2bb0ae23a..ad0d5f6af291 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -500,4 +500,5 @@ source "drivers/misc/cardreader/Kconfig"
> source "drivers/misc/habanalabs/Kconfig"
> source "drivers/misc/uacce/Kconfig"
> source "drivers/misc/pvpanic/Kconfig"
> +source "drivers/misc/trinity/Kconfig"
> endmenu
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index 70e800e9127f..c63f3fc89780 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -60,3 +60,4 @@ obj-$(CONFIG_XILINX_SDFEC) += xilinx_sdfec.o
> obj-$(CONFIG_HISI_HIKEY_USB) += hisi_hikey_usb.o
> obj-$(CONFIG_HI6421V600_IRQ) += hi6421v600-irq.o
> obj-$(CONFIG_OPEN_DICE) += open-dice.o
> +obj-$(CONFIG_TRINITY) += trinity/
> diff --git a/drivers/misc/trinity/Kconfig b/drivers/misc/trinity/Kconfig
> new file mode 100644
> index 000000000000..ad4bab78f7c6
> --- /dev/null
> +++ b/drivers/misc/trinity/Kconfig
> @@ -0,0 +1,27 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +config TRINITY
> + bool "Samsung Neural Processing Unit"
> + depends on HAS_IOMEM
> + depends on HAS_DMA
> + default n

The default is 'n', no need to ever say it again.

> + help
> + Select this option to enable driver support for Samsung
> + Neural Processing Unit (NPU).
> +
> + This driver works as a base driver of the other drivers
> + for Trinity device family.
> +
> + This option should be enabled to support Trinity
> + Vision 2 (TRIV2), and Trinity Audio (TRIA).
> +
> +config TRINITY_VISION2
> + tristate "Samsung NPU Trinity Vision 2"

What happened to "vision 1"?

> + depends on TRINITY
> + default n
> + help
> + Select this option to enable driver support for a Samsung
> + Neural Processing Unit (NPU), Tinity Vision 2.
> +
> + This driver enables userspace system library to access the
> + device via /dev/triv2-N.

What is the module name?

Where is the userspace library code that talks to this? Any
documentation for this interface anywhere?

> +#define BASE_DEV_NAME "trinity"

KBUILD_MODNAME?

> +/* A global lock for shared static variables such as dev_bitmap */
> +static DEFINE_SPINLOCK(trinity_lock);

That's a sign something is wrong, you should not need any module-wide
code variables.

> +/* A bitmap to keep track of active Trinity devices */
> +static unsigned long dev_bitmap[TRINITY_DEV_END];

Should not be needed, use a simple ida structure if you really want to
name things cleanly.

> +
> +/**
> + * trinity_release() - A common callback for close() in file_operations for a
> + * Trinity device node. If there are device-specific data to be
> + * cleaned-up, it is required to clean them up before invoke this
> + * callback.
> + *
> + * @inode: Inode to be closed
> + * @file: File to be closed
> + *
> + * Returns 0 on success. Otherwise, returns negative error.
> + */
> +int trinity_release(struct inode *inode, struct file *file)
> +{
> + struct trinity_driver *drv;
> +
> + drv = file->private_data;
> +
> + if (drv->verbose)
> + dev_info(drv_to_dev_ptr(drv), "%s\n", "Device closed");
> +
> + mutex_lock(&drv->lock);
> + drv->opened = drv->opened - 1;

That will never work, you can't keep track of open/close calls.

> + if (drv->opened == 0) {
> + /* wait already submitted requests */
> + if (drv->desc->drain_reqs)
> + drv->desc->drain_reqs(drv);
> +
> + drv->desc->set_state(drv, TRINITY_STATE_PAUSE);
> + }
> + mutex_unlock(&drv->lock);
> +
> + return 0;
> +}
> +
> +static bool trinity_is_empty(void)
> +{
> + enum trinity_dev_type type;
> + bool empty = true;
> +
> + spin_lock(&trinity_lock);
> + for (type = TRINITY_DEV_UNKNOWN, type++; type < TRINITY_DEV_END;
> + type++) {
> + if (find_first_bit(&dev_bitmap[type], TRINITY_DEV_EACH_MAX) !=
> + TRINITY_DEV_EACH_MAX) {
> + empty = false;
> + break;
> + }
> + }
> + spin_unlock(&trinity_lock);
> +
> + return empty;
> +}
> +
> +/**
> + * trinity_wait_ready() - Wait until trinity is ready state
> + *
> + * @drv: an instance of trinity driver
> + *
> + * Returns 0 on success. Otherwise, returns negative error.
> + */
> +int trinity_wait_ready(struct trinity_driver *drv)
> +{
> + const unsigned long time_out = HZ / 100UL; /* 1/100 seconds*/
> + const unsigned int max_retry = 10;
> + unsigned int retry = 0;
> + wait_queue_head_t wq;
> +
> + drv->desc->set_state(drv, TRINITY_STATE_READY);
> +
> + init_waitqueue_head(&wq);
> + /* try to ensure that NPU is in the ready state */
> + while (wait_event_timeout(
> + wq, drv->desc->get_state(drv) == TRINITY_STATE_READY,
> + time_out) == 0) {
> + /* regarded as failure */
> + if (retry == max_retry)
> + return -ETIMEDOUT;
> + retry++;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * trinity_open() - A common callback for open() in file_operations for a Trinity
> + * device node. If device-specific open() is required, this
> + * callback should be invoked by that open().
> + *
> + * @inode: inode to be opened
> + * @f: file to be opened
> + *
> + * Returns 0 on success. Otherwise, returns negative error.
> + */
> +int trinity_open(struct inode *inode, struct file *f)
> +{
> + struct miscdevice *miscdev;
> + struct trinity_driver *drv;
> + int ret = 0;
> +
> + miscdev = (struct miscdevice *)f->private_data;

Why the cast?

> + drv = container_of(miscdev, struct trinity_driver, mdev);
> + f->private_data = drv;
> +
> + mutex_lock(&drv->lock);
> + /** remove PAUSE set on the CP of the NPU */
> + if (drv->opened == 0) {
> + ret = trinity_wait_ready(drv);
> + if (ret != 0)
> + goto out;
> + }
> + drv->opened = drv->opened + 1;

Again, trying to keep track of open/close calls will never work. Just
let the vfs handle that for you (you will note it does that already).
Your driver should never need to worry about it.

> +
> + if (drv->verbose)
> + dev_info(drv_to_dev_ptr(drv), "%s\n", "Device opened");
> +
> +out:
> + mutex_unlock(&drv->lock);
> +
> + return 0;
> +}
> +
> +static void trinity_common_init(struct device *dev)
> +{
> + if (!trinity_is_empty())
> + return;
> +
> + /* Common init codes */
> +}

Missing something?

> +
> +static void trinity_common_exit(void)
> +{
> + if (!trinity_is_empty())
> + return;
> +
> + /* Common deinit codes */
> +}
> +

Don't provide empty functions that do nothing please.

> +static int trinity_set_device_id(struct trinity_driver *drv)
> +{
> + const struct trinity_desc *desc = drv->desc;
> + struct device *dev = drv_to_dev_ptr(drv);
> + int err = -EEXIST;
> +
> + spin_lock(&trinity_lock);
> + drv->dev_id =
> + find_first_zero_bit(&dev_bitmap[dev->id], TRINITY_DEV_EACH_MAX);

Again, use an ida structure please.

> + if (drv->dev_id < TRINITY_DEV_EACH_MAX) {
> + set_bit(drv->dev_id, &dev_bitmap[dev->id]);
> + err = 0;
> + }
> + spin_unlock(&trinity_lock);
> +
> + if (err == 0) {
> + drv->name = devm_kasprintf(dev, GFP_KERNEL, "%s-%u", desc->type,
> + drv->dev_id);
> + err = IS_ERR_OR_NULL(drv->name) ? -ENOMEM : 0;

Spell out if statements, this just makes things hard to read. And you
just leaked a "bit" if this failed, so are you sure this was ever
tested?

> + }
> +
> + return err;
> +}
> +
> +int trinity_create_node(struct trinity_driver *drv)
> +{
> + struct device *dev = drv_to_dev_ptr(drv);
> + int err;
> +
> + /** register as a misc device */
> + drv->mdev.minor = MISC_DYNAMIC_MINOR;
> + drv->mdev.parent = NULL;

No parent device? Why not? What bus does this device live on? This is
a platform device lower on in this code, please use that, don't just
hang out there at the top of the device tree.

> + drv->mdev.name = drv->name;
> +
> + err = misc_register(&drv->mdev);
> + if (err < 0)
> + dev_err(dev, "failed to register as a misc device");
> + else
> + dev_info(dev, "misc device created!");

Again, drivers are quiet if all goes well.

I stopped here.

Also, please remove the layers of abstraction you have in your
structures that you never use, but yet still define in this patch for
some reason...

thanks,

greg k-h