[PATCH v5 08/21] gpu: host1x: Implement /dev/host1x device node

Mikko Perttunen
2021-01-11T13:02:16Z

Add the /dev/host1x device node, implementing the following
functionality:

- Reading syncpoint values
- Allocating syncpoints (providing syncpoint FDs)
- Incrementing syncpoints (based on syncpoint FD)

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
---
v4:
* Put UAPI under CONFIG_DRM_TEGRA_STAGING
v3:
* Pass process name as syncpoint name when allocating
syncpoint.
---
drivers/gpu/host1x/Makefile | 1 +
drivers/gpu/host1x/dev.c | 9 ++
drivers/gpu/host1x/dev.h | 3 +
drivers/gpu/host1x/uapi.c | 282 ++++++++++++++++++++++++++++++++++++
drivers/gpu/host1x/uapi.h | 22 +++
include/linux/host1x.h | 2 +
6 files changed, 319 insertions(+)
create mode 100644 drivers/gpu/host1x/uapi.c
create mode 100644 drivers/gpu/host1x/uapi.h

diff --git a/drivers/gpu/host1x/Makefile b/drivers/gpu/host1x/Makefile
index 096017b8789d..882f928d75e1 100644
--- a/drivers/gpu/host1x/Makefile
+++ b/drivers/gpu/host1x/Makefile
@@ -9,6 +9,7 @@ host1x-y = \
job.o \
debug.o \
mipi.o \
+ uapi.o \
hw/host1x01.o \
hw/host1x02.o \
hw/host1x04.o \
diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index d0ebb70e2fdd..641317d23828 100644
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -461,6 +461,12 @@ static int host1x_probe(struct platform_device *pdev)
goto deinit_syncpt;
}

+ err = host1x_uapi_init(&host->uapi, host);
+ if (err) {
+ dev_err(&pdev->dev, "failed to initialize uapi\n");
+ goto deinit_intr;
+ }
+
host1x_debug_init(host);

if (host->info->has_hypervisor)
@@ -480,6 +486,8 @@ static int host1x_probe(struct platform_device *pdev)
host1x_unregister(host);
deinit_debugfs:
host1x_debug_deinit(host);
+ host1x_uapi_deinit(&host->uapi);
+deinit_intr:
host1x_intr_deinit(host);
deinit_syncpt:
host1x_syncpt_deinit(host);
@@ -501,6 +509,7 @@ static int host1x_remove(struct platform_device *pdev)

host1x_unregister(host);
host1x_debug_deinit(host);
+ host1x_uapi_deinit(&host->uapi);
host1x_intr_deinit(host);
host1x_syncpt_deinit(host);
reset_control_assert(host->rst);
diff --git a/drivers/gpu/host1x/dev.h b/drivers/gpu/host1x/dev.h
index 63010ae37a97..7b8b7e20e32b 100644
--- a/drivers/gpu/host1x/dev.h
+++ b/drivers/gpu/host1x/dev.h
@@ -17,6 +17,7 @@
#include "intr.h"
#include "job.h"
#include "syncpt.h"
+#include "uapi.h"

struct host1x_syncpt;
struct host1x_syncpt_base;
@@ -143,6 +144,8 @@ struct host1x {
struct list_head list;

struct device_dma_parameters dma_parms;
+
+ struct host1x_uapi uapi;
};

void host1x_hypervisor_writel(struct host1x *host1x, u32 r, u32 v);
diff --git a/drivers/gpu/host1x/uapi.c b/drivers/gpu/host1x/uapi.c
new file mode 100644
index 000000000000..27b8761c3f35
--- /dev/null
+++ b/drivers/gpu/host1x/uapi.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * /dev/host1x syncpoint interface
+ *
+ * Copyright (c) 2020, NVIDIA Corporation.
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/cdev.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/host1x.h>
+#include <linux/nospec.h>
+
+#include "dev.h"
+#include "syncpt.h"
+#include "uapi.h"
+
+#include <uapi/linux/host1x.h>
+
+static int syncpt_file_release(struct inode *inode, struct file *file)
+{
+ struct host1x_syncpt *sp = file->private_data;
+
+ host1x_syncpt_put(sp);
+
+ return 0;
+}
+
+static int syncpt_file_ioctl_info(struct host1x_syncpt *sp, void __user *data)
+{
+ struct host1x_syncpoint_info args;
+ unsigned long copy_err;
+
+ copy_err = copy_from_user(&args, data, sizeof(args));
+ if (copy_err)
+ return -EFAULT;
+
+ if (args.reserved[0] || args.reserved[1] || args.reserved[2])
+ return -EINVAL;
+
+ args.id = sp->id;
+
+ copy_err = copy_to_user(data, &args, sizeof(args));
+ if (copy_err)
+ return -EFAULT;
+
+ return 0;
+}
+
+static int syncpt_file_ioctl_incr(struct host1x_syncpt *sp, void __user *data)
+{
+ struct host1x_syncpoint_increment args;
+ unsigned long copy_err;
+ u32 i;
+
+ copy_err = copy_from_user(&args, data, sizeof(args));
+ if (copy_err)
+ return -EFAULT;
+
+ for (i = 0; i < args.count; i++) {
+ host1x_syncpt_incr(sp);
+ if (signal_pending(current))
+ return -EINTR;
+ }
+
+ return 0;
+}
+
+static long syncpt_file_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *data = (void __user *)arg;
+ long err;
+
+ switch (cmd) {
+ case HOST1X_IOCTL_SYNCPOINT_INFO:
+ err = syncpt_file_ioctl_info(file->private_data, data);
+ break;
+
+ case HOST1X_IOCTL_SYNCPOINT_INCREMENT:
+ err = syncpt_file_ioctl_incr(file->private_data, data);
+ break;
+
+ default:
+ err = -ENOTTY;
+ }
+
+ return err;
+}
+
+static const struct file_operations syncpt_file_fops = {
+ .owner = THIS_MODULE,
+ .release = syncpt_file_release,
+ .unlocked_ioctl = syncpt_file_ioctl,
+ .compat_ioctl = syncpt_file_ioctl,
+};
+
+struct host1x_syncpt *host1x_syncpt_fd_get(int fd)
+{
+ struct host1x_syncpt *sp;
+ struct file *file = fget(fd);
+
+ if (!file)
+ return ERR_PTR(-EINVAL);
+
+ if (file->f_op != &syncpt_file_fops) {
+ fput(file);
+ return ERR_PTR(-EINVAL);
+ }
+
+ sp = file->private_data;
+
+ host1x_syncpt_get(sp);
+
+ fput(file);
+
+ return sp;
+}
+EXPORT_SYMBOL(host1x_syncpt_fd_get);
+
+static int dev_file_open(struct inode *inode, struct file *file)
+{
+ struct host1x_uapi *uapi =
+ container_of(inode->i_cdev, struct host1x_uapi, cdev);
+
+ file->private_data = container_of(uapi, struct host1x, uapi);
+
+ return 0;
+}
+
+static int dev_file_ioctl_read_syncpoint(struct host1x *host1x,
+ void __user *data)
+{
+ struct host1x_read_syncpoint args;
+ unsigned long copy_err;
+
+ copy_err = copy_from_user(&args, data, sizeof(args));
+ if (copy_err)
+ return -EFAULT;
+
+ if (args.id >= host1x_syncpt_nb_pts(host1x))
+ return -EINVAL;
+
+ args.id = array_index_nospec(args.id, host1x_syncpt_nb_pts(host1x));
+ args.value = host1x_syncpt_read(&host1x->syncpt[args.id]);
+
+ copy_err = copy_to_user(data, &args, sizeof(args));
+ if (copy_err)
+ return -EFAULT;
+
+ return 0;
+}
+
+static int dev_file_ioctl_alloc_syncpoint(struct host1x *host1x,
+ void __user *data)
+{
+ struct host1x_allocate_syncpoint args;
+ struct host1x_syncpt *sp;
+ unsigned long copy_err;
+ int err;
+
+ copy_err = copy_from_user(&args, data, sizeof(args));
+ if (copy_err)
+ return -EFAULT;
+
+ if (args.reserved[0] || args.reserved[1] || args.reserved[2])
+ return -EINVAL;
+
+ sp = host1x_syncpt_alloc(host1x, HOST1X_SYNCPT_CLIENT_MANAGED,
+ current->comm);
+ if (!sp)
+ return -EBUSY;
+
+ err = anon_inode_getfd("host1x_syncpt", &syncpt_file_fops, sp,
+ O_CLOEXEC);
+ if (err < 0)
+ goto free_syncpt;
+
+ args.fd = err;
+
+ copy_err = copy_to_user(data, &args, sizeof(args));
+ if (copy_err) {
+ err = -EFAULT;
+ goto put_fd;
+ }
+
+ return 0;
+
+put_fd:
+ put_unused_fd(args.fd);
+free_syncpt:
+ host1x_syncpt_put(sp);
+
+ return err;
+}
+
+static long dev_file_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *data = (void __user *)arg;
+ long err;
+
+ switch (cmd) {
+ case HOST1X_IOCTL_READ_SYNCPOINT:
+ err = dev_file_ioctl_read_syncpoint(file->private_data, data);
+ break;
+
+ case HOST1X_IOCTL_ALLOCATE_SYNCPOINT:
+ err = dev_file_ioctl_alloc_syncpoint(file->private_data, data);
+ break;
+
+ default:
+ err = -ENOTTY;
+ }
+
+ return err;
+}
+
+static const struct file_operations dev_file_fops = {
+ .owner = THIS_MODULE,
+ .open = dev_file_open,
+ .unlocked_ioctl = dev_file_ioctl,
+ .compat_ioctl = dev_file_ioctl,
+};
+
+int host1x_uapi_init(struct host1x_uapi *uapi, struct host1x *host1x)
+{
+ int err;
+ dev_t dev_num;
+
+ if (!IS_ENABLED(CONFIG_DRM_TEGRA_STAGING))
+ return 0;
+
+ err = alloc_chrdev_region(&dev_num, 0, 1, "host1x");
+ if (err)
+ return err;
+
+ uapi->class = class_create(THIS_MODULE, "host1x");
+ if (IS_ERR(uapi->class)) {
+ err = PTR_ERR(uapi->class);
+ goto unregister_chrdev_region;
+ }
+
+ cdev_init(&uapi->cdev, &dev_file_fops);
+ err = cdev_add(&uapi->cdev, dev_num, 1);
+ if (err)
+ goto destroy_class;
+
+ uapi->dev = device_create(uapi->class, host1x->dev,
+ dev_num, NULL, "host1x");
+ if (IS_ERR(uapi->dev)) {
+ err = PTR_ERR(uapi->dev);
+ goto del_cdev;
+ }
+
+ cdev_add(&uapi->cdev, dev_num, 1);
+
+ uapi->dev_num = dev_num;
+
+ return 0;
+
+del_cdev:
+ cdev_del(&uapi->cdev);
+destroy_class:
+ class_destroy(uapi->class);
+unregister_chrdev_region:
+ unregister_chrdev_region(dev_num, 1);
+
+ return err;
+}
+
+void host1x_uapi_deinit(struct host1x_uapi *uapi)
+{
+ if (!IS_ENABLED(CONFIG_DRM_TEGRA_STAGING))
+ return;
+
+ device_destroy(uapi->class, uapi->dev_num);
+ cdev_del(&uapi->cdev);
+ class_destroy(uapi->class);
+ unregister_chrdev_region(uapi->dev_num, 1);
+}
diff --git a/drivers/gpu/host1x/uapi.h b/drivers/gpu/host1x/uapi.h
new file mode 100644
index 000000000000..7beb5e44c1b1
--- /dev/null
+++ b/drivers/gpu/host1x/uapi.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2020, NVIDIA Corporation.
+ */
+
+#ifndef HOST1X_UAPI_H
+#define HOST1X_UAPI_H
+
+#include <linux/cdev.h>
+
+struct host1x_uapi {
+ struct class *class;
+
+ struct cdev cdev;
+ struct device *dev;
+ dev_t dev_num;
+};
+
+int host1x_uapi_init(struct host1x_uapi *uapi, struct host1x *host1x);
+void host1x_uapi_deinit(struct host1x_uapi *uapi);
+
+#endif
diff --git a/include/linux/host1x.h b/include/linux/host1x.h
index 107aea29bccb..b3178ae51cae 100644
--- a/include/linux/host1x.h
+++ b/include/linux/host1x.h
@@ -163,6 +163,8 @@ struct host1x_syncpt *host1x_syncpt_alloc(struct host1x *host,
struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp);
u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base);

+struct host1x_syncpt *host1x_syncpt_fd_get(int fd);
+
/*
* host1x channel
*/
--
2.30.0