This module is heavily based on i2c-dev. Once loaded, it provides one dev node per DP AUX channel, named drm_aux-N.
It's possible to know which connector owns this aux channel by looking at the respective sysfs /sys/class/drm_aux-dev/drm_aux-N/connector, if the connector device pointer was correctly set in the aux helper struct.
Two main operations are provided on the registers through ioctls: read and write; and a helper struct is provided for that, used as:
- address is the address of the register to read/write; - len is the number of bytes to read/write; - buf is a pointer to a buffer where to store the read data, or where the data to be written is already stored; - the return value is the number of bytes read/written, on success, or the error code otherwise. The number of read/written bytes is also stored on the len field of the struct.
Signed-off-by: Rafael Antognolli rafael.antognolli@intel.com --- Documentation/ioctl/ioctl-number.txt | 1 + drivers/gpu/drm/Kconfig | 4 + drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/drm_aux-dev.c | 390 +++++++++++++++++++++++++++++++++++ include/uapi/linux/Kbuild | 1 + include/uapi/linux/drm_aux-dev.h | 45 ++++ 6 files changed, 442 insertions(+) create mode 100644 drivers/gpu/drm/drm_aux-dev.c create mode 100644 include/uapi/linux/drm_aux-dev.h
diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt index 611c522..ea76980 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt @@ -93,6 +93,7 @@ Code Seq#(hex) Include File Comments ';' 64-7F linux/vfio.h '@' 00-0F linux/radeonfb.h conflict! '@' 00-0F drivers/video/aty/aty128fb.c conflict! +'@' 10-2F drm_aux-dev 'A' 00-1F linux/apm_bios.h conflict! 'A' 00-0F linux/agpgart.h conflict! and drivers/char/agp/compat_ioctl.h diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 1a0a8df..eae847c 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -25,6 +25,10 @@ config DRM_MIPI_DSI bool depends on DRM
+config DRM_AUX_CHARDEV + tristate "DRM DP AUX Interface" + depends on DRM + config DRM_KMS_HELPER tristate depends on DRM diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 45e7719..a1a94306 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -32,6 +32,7 @@ CFLAGS_drm_trace_points.o := -I$(src)
obj-$(CONFIG_DRM) += drm.o obj-$(CONFIG_DRM_MIPI_DSI) += drm_mipi_dsi.o +obj-$(CONFIG_DRM_AUX_CHARDEV) += drm_aux-dev.o obj-$(CONFIG_DRM_TTM) += ttm/ obj-$(CONFIG_DRM_TDFX) += tdfx/ obj-$(CONFIG_DRM_R128) += r128/ diff --git a/drivers/gpu/drm/drm_aux-dev.c b/drivers/gpu/drm/drm_aux-dev.c new file mode 100644 index 0000000..3ae9064 --- /dev/null +++ b/drivers/gpu/drm/drm_aux-dev.c @@ -0,0 +1,390 @@ +/* + * Copyright © 2015 Intel Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + * + * Authors: + * Rafael Antognolli rafael.antognolli@intel.com + * + */ + +#include <linux/device.h> +#include <linux/fs.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/drm_aux-dev.h> +#include <asm/uaccess.h> +#include <drm/drm_dp_helper.h> +#include <drm/drm_crtc.h> + +struct drm_aux_dev { + struct list_head list; + unsigned index; + struct drm_dp_aux *aux; + struct device *dev; +}; + +#define DRM_AUX_MINORS 256 +static int drm_aux_dev_count = 0; +static LIST_HEAD(drm_aux_dev_list); +static DEFINE_SPINLOCK(drm_aux_dev_list_lock); + +static struct drm_aux_dev *drm_aux_dev_get_by_minor(unsigned index) +{ + struct drm_aux_dev *aux_dev; + + spin_lock(&drm_aux_dev_list_lock); + list_for_each_entry(aux_dev, &drm_aux_dev_list, list) { + if (aux_dev->index == index) + goto found; + } + + aux_dev = NULL; +found: + spin_unlock(&drm_aux_dev_list_lock); + return aux_dev; +} + +static struct drm_aux_dev *drm_aux_dev_get_by_aux(struct drm_dp_aux *aux) +{ + struct drm_aux_dev *aux_dev; + + spin_lock(&drm_aux_dev_list_lock); + list_for_each_entry(aux_dev, &drm_aux_dev_list, list) { + if (aux_dev->aux == aux) + goto found; + } + + aux_dev = NULL; +found: + spin_unlock(&drm_aux_dev_list_lock); + return aux_dev; +} + +static struct drm_aux_dev *get_free_drm_aux_dev(struct drm_dp_aux *aux) +{ + struct drm_aux_dev *aux_dev; + int index; + + spin_lock(&drm_aux_dev_list_lock); + index = drm_aux_dev_count; + spin_unlock(&drm_aux_dev_list_lock); + if (index >= DRM_AUX_MINORS) { + printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n", + index); + return ERR_PTR(-ENODEV); + } + + aux_dev = kzalloc(sizeof(*aux_dev), GFP_KERNEL); + if (!aux_dev) + return ERR_PTR(-ENOMEM); + aux_dev->aux = aux; + aux_dev->index = index; + + spin_lock(&drm_aux_dev_list_lock); + drm_aux_dev_count++; + list_add_tail(&aux_dev->list, &drm_aux_dev_list); + spin_unlock(&drm_aux_dev_list_lock); + return aux_dev; +} + +static void return_drm_aux_dev(struct drm_aux_dev *aux_dev) +{ + spin_lock(&drm_aux_dev_list_lock); + list_del(&aux_dev->list); + spin_unlock(&drm_aux_dev_list_lock); + kfree(aux_dev); +} + +static ssize_t name_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct drm_aux_dev *aux_dev = drm_aux_dev_get_by_minor(MINOR(dev->devt)); + + if (!aux_dev) + return -ENODEV; + return sprintf(buf, "%s\n", aux_dev->aux->name); +} +static DEVICE_ATTR_RO(name); + +static ssize_t connector_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct drm_aux_dev *aux_dev = drm_aux_dev_get_by_minor(MINOR(dev->devt)); + struct drm_dp_aux *aux; + struct device *conn_dev; + struct drm_connector *connector = NULL; + + if (!aux_dev) + return -ENODEV; + aux = aux_dev->aux; + conn_dev = aux->connector; + if (!conn_dev) + return sprintf(buf, "unknown\n"); + + connector = dev_get_drvdata(aux->connector); + + return sprintf(buf, "%s\n", connector->name); +} +static DEVICE_ATTR_RO(connector); + +static struct attribute *drm_aux_attrs[] = { + &dev_attr_name.attr, + &dev_attr_connector.attr, + NULL, +}; +ATTRIBUTE_GROUPS(drm_aux); + +static long auxdev_ioctl_read(struct drm_aux_dev *aux_dev, unsigned long arg) +{ + struct drm_aux_dev_data rdwr_arg; + __u8 *buf; + int res; + + /* Get register address, buffer and read length from user */ + if (copy_from_user(&rdwr_arg, + (struct drm_aux_dev_data __user *)arg, + sizeof(rdwr_arg))) + return -EFAULT; + + buf = memdup_user(rdwr_arg.buf, rdwr_arg.len * sizeof(__u8)); + if (IS_ERR(buf)) + return PTR_ERR(buf); + + /* read register */ + res = drm_dp_dpcd_read(aux_dev->aux, rdwr_arg.address, buf, rdwr_arg.len); + if (res < 0) { + kfree(buf); + return res; + } + + /* return number of read bytes to user */ + rdwr_arg.len = res; + if (copy_to_user((struct drm_aux_dev_data __user *)arg, + &rdwr_arg, sizeof(rdwr_arg))) { + kfree(buf); + return -EFAULT; + } + + /* return the read bytes to user */ + if (copy_to_user((__u8 __user *)rdwr_arg.buf, + buf, rdwr_arg.len)) { + kfree(buf); + return -EFAULT; + } + + kfree(buf); + return res; +} + +static long auxdev_ioctl_write(struct drm_aux_dev *aux_dev, unsigned long arg) +{ + struct drm_aux_dev_data rdwr_arg; + __u8 *buf; + int res; + + /* Get register address and data to write */ + if (copy_from_user(&rdwr_arg, + (struct drm_aux_dev_data __user *)arg, + sizeof(rdwr_arg))) + return -EFAULT; + + buf = memdup_user(rdwr_arg.buf, rdwr_arg.len * sizeof(__u8)); + if (IS_ERR(buf)) + return PTR_ERR(buf); + + /* write register */ + res = drm_dp_dpcd_write(aux_dev->aux, rdwr_arg.address, buf, rdwr_arg.len); + if (res < 0) { + kfree(buf); + return res; + } + + /* return length of written data */ + rdwr_arg.len = res; + if (copy_to_user((struct drm_aux_dev_data __user *)arg, + &rdwr_arg, sizeof(rdwr_arg))) { + kfree(buf); + return -EFAULT; + } + + kfree(buf); + return res; +} + +static long auxdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct drm_aux_dev *aux_dev = file->private_data; + dev_dbg(aux_dev->aux->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n", + cmd, arg); + switch (cmd) { + case DRM_AUX_DEV_READ: + return auxdev_ioctl_read(aux_dev, arg); + case DRM_AUX_DEV_WRITE: + return auxdev_ioctl_write(aux_dev, arg); + default: + return -ENOTTY; + } + + return 0; +} + +static int auxdev_open(struct inode *inode, struct file *file) +{ + unsigned int minor = iminor(inode); + struct drm_aux_dev *aux_dev; + + aux_dev = drm_aux_dev_get_by_minor(minor); + if (!aux_dev) + return -ENODEV; + + file->private_data = aux_dev; + return 0; +} + +static const struct file_operations auxdev_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .unlocked_ioctl = auxdev_ioctl, + .open = auxdev_open, +}; + +static struct class *drm_aux_dev_class; +static int drm_dev_major = -1; + +#define to_auxdev(d) container_of(d, struct drm_aux_dev, aux) + +static int auxdev_attach_aux(struct drm_dp_aux *aux, void *data) +{ + int *major = data; + struct drm_aux_dev *aux_dev; + int res; + + aux_dev = get_free_drm_aux_dev(aux); + if (IS_ERR(aux_dev)) + return PTR_ERR(aux_dev); + + aux_dev->dev = device_create(drm_aux_dev_class, aux->dev, + MKDEV(*major, aux_dev->index), NULL, + "drm_aux-%d", aux_dev->index); + if (IS_ERR(aux_dev->dev)) { + res = PTR_ERR(aux_dev->dev); + goto error; + } + + pr_debug("drm_aux-dev: aux [%s] registered as minor %d\n", + aux->name, aux_dev->index); + return 0; +error: + return_drm_aux_dev(aux_dev); + return res; + +} + +static int auxdev_detach_aux(struct drm_dp_aux *aux, void *data) +{ + int *major = data; + int minor; + struct drm_aux_dev *aux_dev; + + aux_dev = drm_aux_dev_get_by_aux(aux); + if (!aux_dev) /* attach must have failed */ + return 0; + + minor = aux_dev->index; + return_drm_aux_dev(aux_dev); + device_destroy(drm_aux_dev_class, MKDEV(*major, minor)); + + pr_debug("drm_aux-dev: aux [%s] unregistered\n", aux->name); + return 0; +} + +static int auxdev_notifier_call(struct notifier_block *nb, unsigned long action, + void *data) +{ + struct drm_dp_aux *aux = data; + switch (action) { + case DRM_DP_ADD_AUX: + return auxdev_attach_aux(aux, &drm_dev_major); + case DRM_DP_DEL_AUX: + return auxdev_detach_aux(aux, &drm_dev_major); + } + + return 0; +} + +static struct notifier_block auxdev_notifier = { + .notifier_call = auxdev_notifier_call, +}; + +static int __init drm_aux_dev_init(void) +{ + int res; + + printk(KERN_INFO "drm dp aux /dev entries driver\n"); + + res = register_chrdev(0, "aux", &auxdev_fops); + if (res < 0) + goto out; + drm_dev_major = res; + + drm_aux_dev_class = class_create(THIS_MODULE, "drm_aux-dev"); + if (IS_ERR(drm_aux_dev_class)) { + res = PTR_ERR(drm_aux_dev_class); + goto out_unreg_chrdev; + } + drm_aux_dev_class->dev_groups = drm_aux_groups; + + /* Keep track of DP aux that will be added or removed later */ + res = drm_dp_aux_register_notifier(&auxdev_notifier); + if (res) + goto out_unreg_class; + + /* Bind to already existing DP aux */ + res = drm_dp_aux_for_each(&drm_dev_major, auxdev_attach_aux); + + return 0; + +out_unreg_class: + class_destroy(drm_aux_dev_class); +out_unreg_chrdev: + unregister_chrdev(drm_dev_major, "aux"); +out: + printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__); + return res; +} + +static void __exit drm_aux_dev_exit(void) +{ + printk(KERN_INFO "drm dp aux /dev entries driver - unloading\n"); + drm_dp_aux_unregister_notifier(&auxdev_notifier); + drm_dp_aux_for_each(&drm_dev_major, auxdev_detach_aux); + class_destroy(drm_aux_dev_class); + unregister_chrdev(drm_dev_major, "aux"); +} + +MODULE_AUTHOR("Rafael Antognolli rafael.antognolli@intel.com"); +MODULE_DESCRIPTION("DRM DP AUX /dev entries driver"); +MODULE_LICENSE("GPL"); + +module_init(drm_aux_dev_init); +module_exit(drm_aux_dev_exit); diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild index 1ff9942..07cdc8c 100644 --- a/include/uapi/linux/Kbuild +++ b/include/uapi/linux/Kbuild @@ -105,6 +105,7 @@ header-y += dm-ioctl.h header-y += dm-log-userspace.h header-y += dn.h header-y += dqblk_xfs.h +header-y += drm_aux-dev.h header-y += edd.h header-y += efs_fs_sb.h header-y += elfcore.h diff --git a/include/uapi/linux/drm_aux-dev.h b/include/uapi/linux/drm_aux-dev.h new file mode 100644 index 0000000..668b631 --- /dev/null +++ b/include/uapi/linux/drm_aux-dev.h @@ -0,0 +1,45 @@ +/* + * Copyright © 2015 Intel Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + * + * Authors: + * Rafael Antognolli rafael.antognolli@intel.com + * + */ + +#ifndef _UAPI_LINUX_DRM_AUX_DEV_H +#define _UAPI_LINUX_DRM_AUX_DEV_H + +#include <linux/ioctl.h> +#include <linux/types.h> + +#define DRM_AUX_DEV_MAGIC '@' + +struct drm_aux_dev_data { + __u32 address; /* of the register */ + __u16 len; /* size of the read/write */ + __u8 *buf; +}; + +#define DRM_AUX_DEV_READ _IOWR(DRM_AUX_DEV_MAGIC, 0x10, struct drm_aux_dev_data) +#define DRM_AUX_DEV_WRITE _IOW(DRM_AUX_DEV_MAGIC, 0x11, struct drm_aux_dev_data) + +#endif // _UAPI_LINUX_DRM_AUX_DEV_H