[PATCH 09/10] drm/gud: Add functionality for the USB gadget side

Noralf Trønnes
2020-04-29T12:58:11Z

Since the USB gadget/device has to reach into the DRM internals, part of
the code is placed in the DRM subsystem as a separate module. All calls
into this module runs in process context and are serialized, except one
function that runs in interrupt context.

Since both the gadget side and the DRM side can disable the gadget,
special care has been taken to make that safe.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
---
drivers/gpu/drm/gud/Kconfig | 6 +
drivers/gpu/drm/gud/Makefile | 1 +
drivers/gpu/drm/gud/gud_drm_gadget.c | 1169 ++++++++++++++++++++++++++
include/drm/gud_drm.h | 13 +
4 files changed, 1189 insertions(+)
create mode 100644 drivers/gpu/drm/gud/gud_drm_gadget.c

diff --git a/drivers/gpu/drm/gud/Kconfig b/drivers/gpu/drm/gud/Kconfig
index 203d4490f1c7..99bfbfbf9023 100644
--- a/drivers/gpu/drm/gud/Kconfig
+++ b/drivers/gpu/drm/gud/Kconfig
@@ -12,3 +12,9 @@ config DRM_GUD
adapters.

If M is selected the module will be called gud_drm.
+
+config DRM_GUD_GADGET
+ tristate
+ depends on DRM
+ select LZ4_DECOMPRESS
+ select BACKLIGHT_CLASS_DEVICE
diff --git a/drivers/gpu/drm/gud/Makefile b/drivers/gpu/drm/gud/Makefile
index 73ed7ef3da94..fb5cfbd93d0f 100644
--- a/drivers/gpu/drm/gud/Makefile
+++ b/drivers/gpu/drm/gud/Makefile
@@ -2,3 +2,4 @@

gud_drm-objs := gud_drm_drv.o gud_drm_pipe.o gud_drm_connector.o
obj-$(CONFIG_DRM_GUD) += gud_drm.o
+obj-$(CONFIG_DRM_GUD_GADGET) += gud_drm_gadget.o
diff --git a/drivers/gpu/drm/gud/gud_drm_gadget.c b/drivers/gpu/drm/gud/gud_drm_gadget.c
new file mode 100644
index 000000000000..a9c916abec85
--- /dev/null
+++ b/drivers/gpu/drm/gud/gud_drm_gadget.c
@@ -0,0 +1,1169 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2020 Noralf Trønnes
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/lz4.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+
+#include <drm/drm_client.h>
+#include <drm/drm_connector.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_mode_object.h>
+#include <drm/drm_plane.h>
+#include <drm/drm_rect.h>
+#include <drm/gud_drm.h>
+
+#include "gud_drm_internal.h"
+
+/*
+ * Concurrency:
+ * Calls into this module from f_gud_drm are serialized and run in process
+ * context except gud_drm_gadget_ctrl_get() which is run in interrupt context.
+ *
+ * Termination:
+ * A DRM client can not release itself, only the DRM driver which resources the
+ * client uses can do that.
+ * This means that there are 2 paths to stop the gadget function:
+ * - Unregistering the DRM driver (module unload)
+ * - Disabling the USB gadget (configfs unbind)
+ *
+ * A use counter protects the gadget should the client go away. A kref is used
+ * to control the release of the gud_drm_gadget structure shared by the 2 actors.
+ *
+ * Backlight:
+ * If there's a backlight device it's attached to the first connector.
+ */
+
+struct gud_drm_gadget_connector {
+ struct drm_connector *connector;
+
+ const struct gud_drm_property *properties;
+ unsigned int num_properties;
+ const char *tv_mode_enum_names;
+ unsigned int num_tv_mode_enum_names;
+ struct backlight_device *backlight;
+
+ spinlock_t lock; /* Protects the following members: */
+ enum drm_connector_status status;
+ unsigned int width_mm;
+ unsigned int height_mm;
+ struct gud_drm_display_mode *modes;
+ unsigned int num_modes;
+ void *edid;
+ size_t edid_len;
+ bool changed;
+};
+
+struct gud_drm_gadget {
+ struct kref refcount;
+ refcount_t usecnt;
+ struct drm_client_dev client;
+ struct backlight_device *backlight;
+
+ const u32 *formats;
+ unsigned int format_count;
+
+ const struct gud_drm_property *properties;
+ unsigned int num_properties;
+
+ struct gud_drm_gadget_connector *connectors;
+ unsigned int connector_count;
+
+ struct drm_rect set_buffer_rect;
+ u32 set_buffer_length;
+ u8 set_buffer_compression;
+ u32 set_buffer_compressed_length;
+
+ struct drm_client_buffer *buffer;
+ struct drm_client_buffer *buffer_check;
+ u8 brightness;
+ bool check_ok;
+
+ size_t max_buffer_size;
+ void *work_buf;
+};
+
+static int gud_drm_gadget_probe_connector(struct gud_drm_gadget_connector *gconn)
+{
+ struct drm_connector *connector = gconn->connector;
+ struct gud_drm_display_mode *modes = NULL;
+ struct drm_device *drm = connector->dev;
+ struct drm_display_mode *mode;
+ void *edid_data, *edid = NULL;
+ unsigned int num_modes = 0;
+ size_t edid_len = 0;
+ unsigned long flags;
+ unsigned int i = 0;
+ int ret = 0;
+
+ mutex_lock(&drm->mode_config.mutex);
+
+ connector->funcs->fill_modes(connector,
+ drm->mode_config.max_width,
+ drm->mode_config.max_height);
+
+ list_for_each_entry(mode, &connector->modes, head)
+ num_modes++;
+
+ if (!num_modes)
+ goto update;
+
+ modes = kmalloc_array(num_modes, sizeof(*modes), GFP_KERNEL);
+ if (!modes) {
+ ret = -ENOMEM;
+ num_modes = 0;
+ goto update;
+ }
+
+ list_for_each_entry(mode, &connector->modes, head)
+ gud_drm_from_display_mode(&modes[i++], mode);
+
+ if (!connector->edid_blob_ptr)
+ goto update;
+
+ edid_data = connector->edid_blob_ptr->data;
+ edid_len = connector->edid_blob_ptr->length;
+ if (!edid_data || !edid_len) {
+ edid_len = 0;
+ goto update;
+ }
+
+ edid = kmemdup(edid_data, edid_len, GFP_KERNEL);
+ if (!edid) {
+ ret = -ENOMEM;
+ edid_len = 0;
+ }
+
+update:
+ spin_lock_irqsave(&gconn->lock, flags);
+ if (gconn->status != connector->status || gconn->num_modes != num_modes ||
+ gconn->edid_len != edid_len ||
+ (gconn->modes && modes && memcmp(gconn->modes, modes, num_modes * sizeof(*modes))) ||
+ (gconn->edid && edid && memcmp(gconn->edid, edid, edid_len)))
+ gconn->changed = true;
+ swap(gconn->modes, modes);
+ gconn->num_modes = num_modes;
+ swap(gconn->edid, edid);
+ gconn->edid_len = edid_len;
+ gconn->width_mm = connector->display_info.width_mm;
+ gconn->height_mm = connector->display_info.height_mm;
+ gconn->status = connector->status;
+ spin_unlock_irqrestore(&gconn->lock, flags);
+
+ mutex_unlock(&drm->mode_config.mutex);
+
+ kfree(edid);
+ kfree(modes);
+
+ return ret;
+}
+
+static void gud_drm_gadget_probe_connectors(struct gud_drm_gadget *gdg)
+{
+ unsigned int i;
+
+ for (i = 0; i < gdg->connector_count; i++)
+ gud_drm_gadget_probe_connector(&gdg->connectors[i]);
+}
+
+static bool gud_drm_gadget_check_buffer(struct gud_drm_gadget *gdg,
+ struct drm_client_buffer *buffer,
+ struct drm_display_mode *mode,
+ u32 format)
+{
+ struct drm_framebuffer *fb;
+
+ if (!buffer)
+ return false;
+
+ fb = buffer->fb;
+
+ return fb->format->format == format &&
+ fb->width == mode->hdisplay && fb->height == mode->vdisplay;
+}
+
+static bool gud_drm_gadget_set_connector_property(struct drm_client_dev *client,
+ struct drm_connector *connector,
+ u16 prop, u64 val, int *ret)
+{
+ struct drm_mode_config *config = &connector->dev->mode_config;
+ struct drm_property *property;
+
+ switch (prop) {
+ case GUD_DRM_PROPERTY_TV_SELECT_SUBCONNECTOR:
+ property = config->tv_select_subconnector_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_LEFT_MARGIN:
+ property = config->tv_left_margin_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_RIGHT_MARGIN:
+ property = config->tv_right_margin_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_TOP_MARGIN:
+ property = config->tv_top_margin_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_BOTTOM_MARGIN:
+ property = config->tv_bottom_margin_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_MODE:
+ property = config->tv_mode_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_BRIGHTNESS:
+ property = config->tv_brightness_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_CONTRAST:
+ property = config->tv_contrast_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_FLICKER_REDUCTION:
+ property = config->tv_flicker_reduction_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_OVERSCAN:
+ property = config->tv_overscan_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_SATURATION:
+ property = config->tv_saturation_property;
+ break;
+ case GUD_DRM_PROPERTY_TV_HUE:
+ property = config->tv_hue_property;
+ break;
+ default:
+ return false;
+ }
+
+ *ret = drm_client_modeset_set_property(client, &connector->base, property, val);
+
+ return true;
+}
+
+static int gud_drm_gadget_check(struct gud_drm_gadget *gdg, struct gud_drm_req_set_state *req,
+ size_t size)
+{
+ struct drm_client_dev *client = &gdg->client;
+ u32 format = le32_to_cpu(req->format);
+ struct drm_client_buffer *buffer;
+ struct drm_connector *connector;
+ struct drm_display_mode mode;
+ unsigned int i;
+ void *vaddr;
+ int ret;
+
+ if (size < sizeof(struct gud_drm_req_set_state))
+ return -EINVAL;
+
+ if (size != struct_size(req, properties, req->num_properties))
+ return -EINVAL;
+
+ memset(&mode, 0, sizeof(mode));
+ gud_drm_to_display_mode(&mode, &req->mode);
+
+ gdg->check_ok = false;
+
+ if (!mode.hdisplay || !format)
+ return -EINVAL;
+
+ if (req->connector >= gdg->connector_count)
+ return -EINVAL;
+
+ connector = gdg->connectors[req->connector].connector;
+
+ if (gdg->buffer_check) {
+ drm_client_framebuffer_delete(gdg->buffer_check);
+ gdg->buffer_check = NULL;
+ }
+
+ if (!gud_drm_gadget_check_buffer(gdg, gdg->buffer, &mode, format)) {
+ buffer = drm_client_framebuffer_create(client, mode.hdisplay, mode.vdisplay,
+ format);
+ if (IS_ERR(buffer))
+ return PTR_ERR(buffer);
+
+ vaddr = drm_client_buffer_vmap(buffer);
+ if (IS_ERR(vaddr)) {
+ drm_client_framebuffer_delete(buffer);
+ return PTR_ERR(vaddr);
+ }
+
+ gdg->buffer_check = buffer;
+ } else {
+ buffer = gdg->buffer;
+ }
+
+ ret = drm_client_modeset_set(client, connector, &mode, buffer->fb);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < req->num_properties; i++) {
+ u16 prop = le16_to_cpu(req->properties[i].prop);
+ u64 val = le64_to_cpu(req->properties[i].val);
+
+ if (gud_drm_gadget_set_connector_property(client, connector, prop, val, &ret)) {
+ if (ret)
+ return ret;
+ continue;
+ }
+
+ switch (prop) {
+ case GUD_DRM_PROPERTY_BACKLIGHT_BRIGHTNESS:
+ if (val > 100)
+ return -EINVAL;
+ gdg->brightness = val;
+ break;
+ case GUD_DRM_PROPERTY_ROTATION:
+ ret = drm_client_modeset_set_rotation(client, val);
+ break;
+ default:
+ pr_err("%s: Unknown property: %u\n", __func__, prop);
+ continue;
+ }
+
+ if (ret)
+ return ret;
+ }
+
+ ret = drm_client_modeset_check(&gdg->client);
+ if (ret)
+ return ret;
+
+ gdg->check_ok = true;
+
+ return 0;
+}
+
+static int gud_drm_gadget_commit(struct gud_drm_gadget *gdg)
+{
+ int ret;
+
+ if (!gdg->check_ok)
+ return -EINVAL;
+
+ if (gdg->backlight) {
+ int val, max_brightness = gdg->backlight->props.max_brightness;
+
+ val = DIV64_U64_ROUND_UP(gdg->brightness * max_brightness, 100);
+ ret = backlight_device_set_brightness(gdg->backlight, val);
+ if (ret)
+ return ret;
+ }
+
+ ret = drm_client_modeset_commit(&gdg->client);
+ if (ret)
+ return ret;
+
+ if (gdg->buffer_check) {
+ drm_client_framebuffer_delete(gdg->buffer);
+ gdg->buffer = gdg->buffer_check;
+ gdg->buffer_check = NULL;
+ }
+
+ return 0;
+}
+
+static size_t gud_drm_gadget_write_buffer_memcpy(struct drm_client_buffer *buffer,
+ const void *src, size_t len,
+ struct drm_rect *rect)
+{
+ unsigned int cpp = buffer->fb->format->cpp[0];
+ size_t dst_pitch = buffer->fb->pitches[0];
+ size_t src_pitch = drm_rect_width(rect) * cpp;
+ unsigned int y;
+ void *dst;
+
+ /* Get the address, it's already mapped */
+ dst = drm_client_buffer_vmap(buffer);
+ dst += rect->y1 * dst_pitch;
+ dst += rect->x1 * cpp;
+
+ for (y = 0; y < drm_rect_height(rect) && len; y++) {
+ src_pitch = min(src_pitch, len);
+ memcpy(dst, src, src_pitch);
+ src += src_pitch;
+ dst += dst_pitch;
+ len -= src_pitch;
+ }
+
+ return len;
+}
+
+static bool gud_drm_gadget_check_rect(struct drm_client_buffer *buffer, struct drm_rect *rect)
+{
+ return buffer->fb && rect->x1 < rect->x2 && rect->y1 < rect->y2 &&
+ rect->x2 <= buffer->fb->width && rect->y2 <= buffer->fb->height;
+}
+
+int gud_drm_gadget_write_buffer(struct gud_drm_gadget *gdg, const void *buf, size_t len)
+{
+ struct drm_client_buffer *buffer = gdg->buffer ? gdg->buffer : gdg->buffer_check;
+ struct drm_rect *rect = &gdg->set_buffer_rect;
+ u8 compression = gdg->set_buffer_compression;
+ struct drm_framebuffer *fb;
+ size_t remain;
+ int ret;
+
+ pr_debug("%s: len=%zu compression=0x%x\n", __func__, len, compression);
+
+ if (WARN_ON_ONCE(!buffer))
+ return -ENOMEM;
+
+ if (!gud_drm_gadget_check_rect(buffer, rect)) {
+ pr_err("%s: Rectangle doesn't fit\n", __func__);
+ return -EINVAL;
+ }
+
+ fb = buffer->fb;
+
+ if (compression & GUD_DRM_COMPRESSION_LZ4) {
+ if (len != gdg->set_buffer_compressed_length) {
+ pr_err("%s: Buffer compressed len differs: %zu != %zu\n",
+ __func__, len, gdg->set_buffer_compressed_length);
+ return -EINVAL;
+ }
+
+ ret = LZ4_decompress_safe(buf, gdg->work_buf, len, gdg->max_buffer_size);
+ if (ret < 0) {
+ pr_err("%s: Failed to decompress buffer\n", __func__);
+ return -EIO;
+ }
+
+ buf = gdg->work_buf;
+ len = ret;
+ }
+
+ if (len != gdg->set_buffer_length) {
+ pr_err("%s: Buffer len differs: %zu != %zu\n",
+ __func__, len, gdg->set_buffer_length);
+ return -EINVAL;
+ }
+
+ if (len > (drm_rect_width(rect) * drm_rect_height(rect) * fb->format->cpp[0])) {
+ pr_err("%s: Buffer is too big for rectangle\n", __func__);
+ return -EINVAL;
+ }
+
+ remain = gud_drm_gadget_write_buffer_memcpy(buffer, buf, len, rect);
+ if (remain) {
+ pr_err("%s: Failed to write buffer: remain=%zu\n", __func__, remain);
+ return -EIO;
+ }
+
+ return drm_client_framebuffer_flush(buffer, rect);
+}
+EXPORT_SYMBOL(gud_drm_gadget_write_buffer);
+
+int gud_drm_gadget_set_buffer(struct gud_drm_gadget *gdg, struct gud_drm_req_set_buffer *req)
+{
+ u32 compressed_length = le32_to_cpu(req->compressed_length);
+ u32 length = le32_to_cpu(req->length);
+ struct drm_client_buffer *buffer;
+ struct drm_rect rect;
+ int ret = 0;
+
+ if (!refcount_inc_not_zero(&gdg->usecnt))
+ return -ENODEV;
+
+ buffer = gdg->buffer ? gdg->buffer : gdg->buffer_check;
+ if (!buffer) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ drm_rect_init(&rect, le32_to_cpu(req->x), le32_to_cpu(req->y),
+ le32_to_cpu(req->width), le32_to_cpu(req->height));
+
+ pr_debug("%s: " DRM_RECT_FMT "\n", __func__, DRM_RECT_ARG(&rect));
+
+ if (!gud_drm_gadget_check_rect(buffer, &rect)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (req->compression & ~GUD_DRM_COMPRESSION_LZ4) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ gdg->set_buffer_rect = rect;
+ gdg->set_buffer_length = length;
+
+ if (req->compression) {
+ if (!compressed_length) {
+ ret = -EINVAL;
+ goto out;
+ }
+ gdg->set_buffer_compression = req->compression;
+ gdg->set_buffer_compressed_length = compressed_length;
+ length = compressed_length;
+ } else {
+ gdg->set_buffer_compression = 0;
+ gdg->set_buffer_compressed_length = 0;
+ }
+out:
+ refcount_dec(&gdg->usecnt);
+
+ return ret ? ret : length;
+}
+EXPORT_SYMBOL(gud_drm_gadget_set_buffer);
+
+static void gud_drm_gadget_delete_buffers(struct gud_drm_gadget *gdg)
+{
+ drm_client_framebuffer_delete(gdg->buffer_check);
+ drm_client_framebuffer_delete(gdg->buffer);
+ gdg->buffer_check = NULL;
+ gdg->buffer = NULL;
+}
+
+int gud_drm_gadget_disable_pipe(struct gud_drm_gadget *gdg)
+{
+ int ret;
+
+ drm_client_modeset_set(&gdg->client, NULL, NULL, NULL);
+ ret = drm_client_modeset_commit(&gdg->client);
+ if (ret)
+ return ret;
+
+ gud_drm_gadget_delete_buffers(gdg);
+
+ return 0;
+}
+EXPORT_SYMBOL(gud_drm_gadget_disable_pipe);
+
+static int gud_drm_gadget_ctrl_get_display_descriptor(struct gud_drm_gadget *gdg, u16 value,
+ void *data, size_t size)
+{
+ struct drm_device *drm = gdg->client.dev;
+ struct gud_drm_display_descriptor desc;
+ u8 type = value >> 8;
+ u8 index = value & 0xff;
+
+ if (type != GUD_DRM_USB_DT_DISPLAY || index)
+ return -EINVAL;
+
+ desc.bLength = sizeof(desc);
+ desc.bDescriptorType = GUD_DRM_USB_DT_DISPLAY;
+
+ desc.bVersion = 1;
+ desc.bMaxBufferSizeOrder = ilog2(gdg->max_buffer_size);
+ desc.bmFlags = 0;
+ desc.bCompression = GUD_DRM_COMPRESSION_LZ4;
+
+ desc.dwMinWidth = cpu_to_le32(drm->mode_config.min_width);
+ desc.dwMaxWidth = cpu_to_le32(drm->mode_config.max_width);
+ desc.dwMinHeight = cpu_to_le32(drm->mode_config.min_height);
+ desc.dwMaxHeight = cpu_to_le32(drm->mode_config.max_height);
+ desc.bNumFormats = gdg->format_count;
+ desc.bNumProperties = gdg->num_properties;
+ desc.bNumConnectors = gdg->connector_count;
+
+ size = min(size, sizeof(desc));
+ memcpy(data, &desc, size);
+
+ return size;
+}
+
+static void gud_drm_gadget_ctrl_get_formats(struct gud_drm_gadget *gdg, __le32 *formats)
+{
+ unsigned int i;
+
+ for (i = 0; i < gdg->format_count; i++)
+ formats[i] = cpu_to_le32(gdg->formats[i]);
+}
+
+static int gud_drm_gadget_ctrl_get_connector(struct gud_drm_gadget *gdg, unsigned int index,
+ struct gud_drm_req_get_connector *desc)
+{
+ struct gud_drm_gadget_connector *gconn;
+
+ if (index >= gdg->connector_count)
+ return -EINVAL;
+
+ memset(desc, 0, sizeof(*desc));
+
+ gconn = &gdg->connectors[index];
+
+ desc->connector_type = gconn->connector->connector_type;
+ desc->flags = cpu_to_le32(GUD_DRM_CONNECTOR_FLAGS_POLL);
+ desc->num_properties = gconn->num_properties;
+
+ return 0;
+}
+
+static struct gud_drm_gadget_connector *
+gud_drm_gadget_get_gconn(struct gud_drm_gadget *gdg, unsigned int index)
+{
+ if (index >= gdg->connector_count)
+ return NULL;
+
+ return &gdg->connectors[index];
+}
+
+static int gud_drm_gadget_ctrl_get_connector_status(struct gud_drm_gadget *gdg, unsigned int index,
+ struct gud_drm_req_get_connector_status *status)
+{
+ struct gud_drm_gadget_connector *gconn;
+ unsigned long flags;
+
+ gconn = gud_drm_gadget_get_gconn(gdg, index);
+ if (!gconn)
+ return -ENOENT;
+
+ memset(status, 0, sizeof(*status));
+
+ spin_lock_irqsave(&gconn->lock, flags);
+ status->status = gconn->status;
+ if (gconn->changed) {
+ status->status |= GUD_DRM_CONNECTOR_STATUS_CHANGED;
+ gconn->changed = false;
+ }
+ if (gconn->num_modes)
+ status->num_modes = cpu_to_le16(gconn->num_modes);
+ if (gconn->edid_len)
+ status->edid_len = cpu_to_le16(gconn->edid_len);
+ spin_unlock_irqrestore(&gconn->lock, flags);
+
+ return 0;
+}
+
+/* This runs in interrupt context */
+int gud_drm_gadget_ctrl_get(struct gud_drm_gadget *gdg, u8 request,
+ u16 index, void *data, size_t size)
+{
+ struct gud_drm_gadget_connector *gconn;
+ unsigned long flags;
+ int ret = -EINVAL;
+
+ pr_debug("%s: request=0x%x index=%u size=%zu\n", __func__, request, index, size);
+
+ if (!refcount_inc_not_zero(&gdg->usecnt))
+ return -ENODEV;
+
+ if (!size)
+ goto out;
+
+ switch (request) {
+ case USB_REQ_GET_DESCRIPTOR:
+ ret = gud_drm_gadget_ctrl_get_display_descriptor(gdg, index, data, size);
+ break;
+ case GUD_DRM_USB_REQ_GET_FORMATS:
+ if (!index && size == gdg->format_count * sizeof(u32)) {
+ gud_drm_gadget_ctrl_get_formats(gdg, data);
+ ret = 0;
+ }
+ break;
+ case GUD_DRM_USB_REQ_GET_PROPERTIES:
+ if (!index && size == gdg->num_properties * sizeof(*gdg->properties)) {
+ memcpy(data, gdg->properties, size);
+ ret = 0;
+ }
+ break;
+ case GUD_DRM_USB_REQ_GET_CONNECTOR:
+ if (size == sizeof(struct gud_drm_req_get_connector))
+ ret = gud_drm_gadget_ctrl_get_connector(gdg, index, data);
+ break;
+ case GUD_DRM_USB_REQ_GET_CONNECTOR_PROPERTIES:
+ gconn = gud_drm_gadget_get_gconn(gdg, index);
+ if (gconn && size == gconn->num_properties * sizeof(*gconn->properties)) {
+ memcpy(data, gconn->properties, size);
+ ret = 0;
+ }
+ break;
+ case GUD_DRM_USB_REQ_GET_CONNECTOR_TV_MODE_VALUES:
+ gconn = gud_drm_gadget_get_gconn(gdg, index);
+ if (gconn && size == gconn->num_tv_mode_enum_names * DRM_PROP_NAME_LEN) {
+ memcpy(data, gconn->tv_mode_enum_names, size);
+ ret = 0;
+ }
+ break;
+ case GUD_DRM_USB_REQ_GET_CONNECTOR_STATUS:
+ if (size == sizeof(struct gud_drm_req_get_connector_status))
+ ret = gud_drm_gadget_ctrl_get_connector_status(gdg, index, data);
+ break;
+ case GUD_DRM_USB_REQ_GET_CONNECTOR_MODES:
+ gconn = gud_drm_gadget_get_gconn(gdg, index);
+ spin_lock_irqsave(&gconn->lock, flags);
+ if (gconn && size == gconn->num_modes * sizeof(*gconn->modes)) {
+ memcpy(data, gconn->modes, size);
+ ret = 0;
+ }
+ spin_unlock_irqrestore(&gconn->lock, flags);
+ break;
+ case GUD_DRM_USB_REQ_GET_CONNECTOR_EDID:
+ gconn = gud_drm_gadget_get_gconn(gdg, index);
+ spin_lock_irqsave(&gconn->lock, flags);
+ if (gconn && size == gconn->edid_len) {
+ memcpy(data, gconn->edid, size);
+ ret = 0;
+ }
+ spin_unlock_irqrestore(&gconn->lock, flags);
+ break;
+ }
+out:
+ refcount_dec(&gdg->usecnt);
+
+ return !ret ? size : ret;
+}
+EXPORT_SYMBOL(gud_drm_gadget_ctrl_get);
+
+int gud_drm_gadget_ctrl_set(struct gud_drm_gadget *gdg, u8 request,
+ u16 index, void *data, size_t size)
+{
+ struct gud_drm_gadget_connector *gconn;
+ int dpms, ret = -EINVAL;
+
+ pr_debug("%s: request=0x%x index=%u size=%zu\n", __func__, request, index, size);
+
+ if (!refcount_inc_not_zero(&gdg->usecnt))
+ return -ENODEV;
+
+ switch (request) {
+ case GUD_DRM_USB_REQ_SET_CONNECTOR_FORCE_DETECT:
+ gconn = gud_drm_gadget_get_gconn(gdg, index);
+ if (gconn)
+ ret = gud_drm_gadget_probe_connector(gconn);
+ break;
+ case GUD_DRM_USB_REQ_SET_STATE_CHECK:
+ ret = gud_drm_gadget_check(gdg, data, size);
+ break;
+ case GUD_DRM_USB_REQ_SET_STATE_COMMIT:
+ if (!size)
+ ret = gud_drm_gadget_commit(gdg);
+ break;
+ case GUD_DRM_USB_REQ_SET_CONTROLLER_ENABLE:
+ if (size == sizeof(u8)) {
+ if (*(u8 *)data == 0)
+ ret = gud_drm_gadget_disable_pipe(gdg);
+ else
+ ret = 0;
+ }
+ break;
+ case GUD_DRM_USB_REQ_SET_DISPLAY_ENABLE:
+ if (size == sizeof(u8)) {
+ dpms = *(u8 *)data ? DRM_MODE_DPMS_ON : DRM_MODE_DPMS_OFF;
+ ret = drm_client_modeset_dpms(&gdg->client, dpms);
+ }
+ break;
+ }
+
+ refcount_dec(&gdg->usecnt);
+
+ return ret;
+}
+EXPORT_SYMBOL(gud_drm_gadget_ctrl_set);
+
+static int gud_drm_gadget_get_formats(struct gud_drm_gadget *gdg, u8 *max_cpp)
+{
+ struct drm_device *drm = gdg->client.dev;
+ struct drm_plane *plane;
+ unsigned int i;
+ u32 *formats;
+ int ret;
+
+ *max_cpp = 0;
+
+ drm_for_each_plane(plane, drm) {
+ if (plane->type == DRM_PLANE_TYPE_PRIMARY)
+ break;
+ }
+
+ formats = kcalloc(plane->format_count, sizeof(u32), GFP_KERNEL);
+ if (!formats)
+ return -ENOMEM;
+
+ for (i = 0; i < plane->format_count; i++) {
+ const struct drm_format_info *fmt;
+
+ fmt = drm_format_info(plane->format_types[i]);
+ if (fmt->num_planes != 1)
+ continue;
+
+ /*
+ * Supporting 24-bit bpp would add complexity so don't bother.
+ * It's hardly used and compression removes much of the gain.
+ */
+ if (fmt->cpp[0] == 3)
+ continue;
+
+ if (*max_cpp < fmt->cpp[0])
+ *max_cpp = fmt->cpp[0];
+
+ formats[gdg->format_count++] = plane->format_types[i];
+ }
+
+ if (!gdg->format_count) {
+ ret = -ENOENT;
+ goto err_free;
+ }
+
+ gdg->formats = formats;
+
+ return 0;
+
+err_free:
+ kfree(formats);
+
+ return ret;
+}
+
+static int gud_drm_gadget_get_rotation_property(struct drm_device *drm, u16 *prop, u64 *val)
+{
+ struct drm_property_enum *prop_enum;
+ struct drm_plane *plane;
+ unsigned int num_props = 0;
+ u16 bitmask = 0;
+
+ drm_for_each_plane(plane, drm) {
+ if (plane->type == DRM_PLANE_TYPE_PRIMARY)
+ break;
+ }
+
+ if (!plane->rotation_property)
+ return 0;
+
+ list_for_each_entry(prop_enum, &plane->rotation_property->enum_list, head) {
+ num_props++;
+ bitmask |= BIT(prop_enum->value);
+ }
+
+ *prop = GUD_DRM_PROPERTY_ROTATION;
+ *val = bitmask;
+
+ return 1;
+}
+
+static int gud_drm_gadget_get_properties(struct gud_drm_gadget *gdg)
+{
+ struct gud_drm_property *properties;
+ u16 prop;
+ u64 val;
+ int ret;
+
+ ret = gud_drm_gadget_get_rotation_property(gdg->client.dev, &prop, &val);
+ if (ret <= 0)
+ return ret;
+
+ properties = kcalloc(1, sizeof(*properties), GFP_KERNEL);
+ if (!properties)
+ return -ENOMEM;
+
+ gdg->properties = properties;
+ gdg->num_properties++;
+
+ properties[0].prop = cpu_to_le16(prop);
+ properties[0].val = cpu_to_le64(val);
+
+ return 0;
+}
+
+static int gud_drm_gadget_get_connector_properties(struct gud_drm_gadget *gdg,
+ struct gud_drm_gadget_connector *gconn)
+{
+ struct drm_device *drm = gdg->client.dev;
+ struct drm_mode_config *config = &drm->mode_config;
+ struct drm_connector *connector = gconn->connector;
+ struct drm_object_properties *conn_props = connector->base.properties;
+ struct gud_drm_property *properties;
+ unsigned int i, ret = 0;
+ u16 prop;
+ u64 val;
+
+ mutex_lock(&drm->mode_config.mutex);
+
+ if (!conn_props->count)
+ goto unlock;
+
+ /* Add room for possible backlight */
+ properties = kcalloc(conn_props->count + 1, sizeof(*properties), GFP_KERNEL);
+ if (!properties) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ gconn->properties = properties;
+
+ for (i = 0; i < conn_props->count; i++) {
+ struct drm_property *property = conn_props->properties[i];
+
+ if (property == config->tv_select_subconnector_property) {
+ prop = GUD_DRM_PROPERTY_TV_SELECT_SUBCONNECTOR;
+ val = connector->state->tv.subconnector;
+ } else if (property == config->tv_left_margin_property) {
+ prop = GUD_DRM_PROPERTY_TV_LEFT_MARGIN;
+ val = connector->state->tv.margins.left;
+ } else if (property == config->tv_right_margin_property) {
+ prop = GUD_DRM_PROPERTY_TV_RIGHT_MARGIN;
+ val = connector->state->tv.margins.right;
+ } else if (property == config->tv_top_margin_property) {
+ prop = GUD_DRM_PROPERTY_TV_TOP_MARGIN;
+ val = connector->state->tv.margins.top;
+ } else if (property == config->tv_bottom_margin_property) {
+ prop = GUD_DRM_PROPERTY_TV_BOTTOM_MARGIN;
+ val = connector->state->tv.margins.bottom;
+ } else if (property == config->tv_mode_property) {
+ struct drm_property_enum *prop_enum;
+ char *buf;
+
+ list_for_each_entry(prop_enum, &property->enum_list, head)
+ gconn->num_tv_mode_enum_names++;
+
+ if (WARN_ON(!gconn->num_tv_mode_enum_names)) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ buf = kcalloc(gconn->num_tv_mode_enum_names, DRM_PROP_NAME_LEN, GFP_KERNEL);
+ if (!buf) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ gconn->tv_mode_enum_names = buf;
+
+ list_for_each_entry(prop_enum, &property->enum_list, head) {
+ strncpy(buf, prop_enum->name, DRM_PROP_NAME_LEN);
+ buf += DRM_PROP_NAME_LEN;
+ }
+
+ prop = GUD_DRM_PROPERTY_TV_MODE;
+ val = connector->state->tv.mode;
+ val |= gconn->num_tv_mode_enum_names << GUD_DRM_USB_CONNECTOR_TV_MODE_NUM_SHIFT;
+ } else if (property == config->tv_brightness_property) {
+ prop = GUD_DRM_PROPERTY_TV_BRIGHTNESS;
+ val = connector->state->tv.brightness;
+ } else if (property == config->tv_contrast_property) {
+ prop = GUD_DRM_PROPERTY_TV_CONTRAST;
+ val = connector->state->tv.contrast;
+ } else if (property == config->tv_flicker_reduction_property) {
+ prop = GUD_DRM_PROPERTY_TV_FLICKER_REDUCTION;
+ val = connector->state->tv.flicker_reduction;
+ } else if (property == config->tv_overscan_property) {
+ prop = GUD_DRM_PROPERTY_TV_OVERSCAN;
+ val = connector->state->tv.overscan;
+ } else if (property == config->tv_saturation_property) {
+ prop = GUD_DRM_PROPERTY_TV_SATURATION;
+ val = connector->state->tv.saturation;
+ } else if (property == config->tv_hue_property) {
+ prop = GUD_DRM_PROPERTY_TV_HUE;
+ val = connector->state->tv.hue;
+ } else {
+ continue;
+ }
+
+ properties[gconn->num_properties].prop = cpu_to_le16(prop);
+ properties[gconn->num_properties++].val = cpu_to_le64(val);
+ }
+
+ if (!connector->index && gdg->backlight) {
+ struct backlight_properties *props = &gdg->backlight->props;
+
+ prop = GUD_DRM_PROPERTY_BACKLIGHT_BRIGHTNESS;
+ val = DIV64_U64_ROUND_UP(props->brightness * 100, props->max_brightness);
+ properties[gconn->num_properties].prop = cpu_to_le16(prop);
+ properties[gconn->num_properties++].val = cpu_to_le64(val);
+ gconn->backlight = gdg->backlight;
+ }
+unlock:
+ mutex_unlock(&drm->mode_config.mutex);
+
+ return ret;
+}
+
+static int gud_drm_gadget_get_connectors(struct gud_drm_gadget *gdg)
+{
+ struct gud_drm_gadget_connector *connectors = NULL;
+ struct drm_connector_list_iter conn_iter;
+ struct drm_device *drm = gdg->client.dev;
+ unsigned int connector_count = 0;
+ struct drm_connector *connector;
+ int ret = 0;
+
+ drm_connector_list_iter_begin(drm, &conn_iter);
+ drm_client_for_each_connector_iter(connector, &conn_iter) {
+ struct gud_drm_gadget_connector *tmp, *gconn;
+
+ tmp = krealloc(connectors, (connector_count + 1) * sizeof(*connectors),
+ GFP_KERNEL | __GFP_ZERO);
+ if (!tmp) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ connectors = tmp;
+ drm_connector_get(connector);
+ gconn = &connectors[connector_count++];
+ gconn->connector = connector;
+ spin_lock_init(&gconn->lock);
+
+ ret = gud_drm_gadget_get_connector_properties(gdg, gconn);
+ if (ret)
+ break;
+ }
+ drm_connector_list_iter_end(&conn_iter);
+
+ gdg->connectors = connectors;
+ gdg->connector_count = connector_count;
+
+ return ret;
+}
+
+static void gud_drm_gadget_release(struct kref *kref)
+{
+ struct gud_drm_gadget *gdg = container_of(kref, struct gud_drm_gadget, refcount);
+
+ kfree(gdg);
+}
+
+static void gud_drm_gadget_put(struct gud_drm_gadget *gdg)
+{
+ kref_put(&gdg->refcount, gud_drm_gadget_release);
+}
+
+static void gud_drm_gadget_client_unregister(struct drm_client_dev *client)
+{
+ struct gud_drm_gadget *gdg = container_of(client, struct gud_drm_gadget, client);
+ int timeout = 10000 / 50;
+ unsigned int i;
+
+ /*
+ * If usecnt doesn't drop to zero, try waiting for the gadget, but we
+ * can't block the DRM driver forever. The worst case wait the gadget side
+ * can hit are tens of seconds through the call to drm_client_modeset_commit().
+ */
+ if (refcount_dec_and_test(&gdg->usecnt)) {
+ for (; timeout && refcount_read(&gdg->usecnt); timeout--)
+ msleep(50);
+ }
+
+ if (!timeout) {
+ pr_err("%s: Timeout waiting for gadget side, will leak memory\n", __func__);
+ return;
+ }
+
+ vfree(gdg->work_buf);
+ kfree(gdg->formats);
+ kfree(gdg->properties);
+
+ for (i = 0; i < gdg->connector_count; i++) {
+ struct gud_drm_gadget_connector *gconn = &gdg->connectors[i];
+
+ drm_connector_put(gconn->connector);
+ kfree(gconn->properties);
+ kfree(gconn->tv_mode_enum_names);
+ kfree(gconn->modes);
+ kfree(gconn->edid);
+ }
+ kfree(gdg->connectors);
+
+ gud_drm_gadget_delete_buffers(gdg);
+ drm_client_release(client);
+ gud_drm_gadget_put(gdg);
+}
+
+static int gud_drm_gadget_client_hotplug(struct drm_client_dev *client)
+{
+ struct gud_drm_gadget *gdg = container_of(client, struct gud_drm_gadget, client);
+
+ gud_drm_gadget_probe_connectors(gdg);
+
+ return 0;
+}
+
+static const struct drm_client_funcs gdg_client_funcs = {
+ .owner = THIS_MODULE,
+ .unregister = gud_drm_gadget_client_unregister,
+ .hotplug = gud_drm_gadget_client_hotplug,
+};
+
+struct gud_drm_gadget *gud_drm_gadget_init(unsigned int minor_id, const char *backlight,
+ size_t *max_buffer_size)
+{
+ struct gud_drm_gadget *gdg;
+ u8 max_cpp;
+ int ret;
+
+ gdg = kzalloc(sizeof(*gdg), GFP_KERNEL);
+ if (!gdg)
+ return ERR_PTR(-ENOMEM);
+
+ ret = drm_client_init_from_id(minor_id, &gdg->client, "gud-drm-gadget", &gdg_client_funcs);
+ if (ret) {
+ pr_err("Failed to aquire minor=%u\n", minor_id);
+ kfree(gdg);
+ return ERR_PTR(ret);
+ }
+
+ refcount_set(&gdg->usecnt, 1);
+ /* The DRM driver (through the client) and f_gud_drm need one ref each */
+ kref_init(&gdg->refcount);
+ kref_get(&gdg->refcount);
+
+ if (backlight) {
+ gdg->backlight = backlight_device_get_by_name(backlight);
+ if (!gdg->backlight) {
+ pr_err("Failed to find backlight: %s\n", backlight);
+ ret = -ENODEV;
+ goto error_release;
+ }
+ }
+
+ ret = gud_drm_gadget_get_formats(gdg, &max_cpp);
+ if (ret) {
+ pr_err("Failed to get formats\n");
+ goto error_release;
+ }
+
+ *max_buffer_size = gdg->client.dev->mode_config.max_width *
+ gdg->client.dev->mode_config.max_height * max_cpp;
+ /* f_gud_drm will kmalloc a buffer of this size */
+ *max_buffer_size = min_t(size_t, *max_buffer_size, KMALLOC_MAX_SIZE);
+
+ gdg->max_buffer_size = *max_buffer_size;
+ gdg->work_buf = vmalloc(gdg->max_buffer_size);
+ if (!gdg->work_buf) {
+ ret = -ENOMEM;
+ goto error_release;
+ }
+
+ ret = gud_drm_gadget_get_properties(gdg);
+ if (ret) {
+ pr_err("Failed to get properties\n");
+ goto error_release;
+ }
+
+ ret = gud_drm_gadget_get_connectors(gdg);
+ if (ret) {
+ pr_err("Failed to get connectors\n");
+ goto error_release;
+ }
+
+ if (!drm_client_register(&gdg->client)) {
+ pr_err("DRM device is gone\n");
+ ret = -ENODEV;
+ goto error_release;
+ }
+
+ gud_drm_gadget_probe_connectors(gdg);
+
+ return gdg;
+
+error_release:
+ gud_drm_gadget_client_unregister(&gdg->client);
+ gud_drm_gadget_fini(gdg);
+
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(gud_drm_gadget_init);
+
+void gud_drm_gadget_fini(struct gud_drm_gadget *gdg)
+{
+ backlight_put(gdg->backlight);
+ gud_drm_gadget_put(gdg);
+}
+EXPORT_SYMBOL(gud_drm_gadget_fini);
+
+MODULE_AUTHOR("Noralf Trønnes");
+MODULE_LICENSE("GPL");
diff --git a/include/drm/gud_drm.h b/include/drm/gud_drm.h
index 15bb30577b57..6afc369274d0 100644
--- a/include/drm/gud_drm.h
+++ b/include/drm/gud_drm.h
@@ -353,4 +353,17 @@ static inline void gud_drm_to_display_mode(struct drm_display_mode *dst,
drm_mode_set_name(dst);
}

+struct gud_drm_gadget;
+
+struct gud_drm_gadget *gud_drm_gadget_init(unsigned int minor_id, const char *backlight,
+ size_t *max_buffer_size);
+void gud_drm_gadget_fini(struct gud_drm_gadget *gdg);
+int gud_drm_gadget_disable_pipe(struct gud_drm_gadget *gdg);
+int gud_drm_gadget_ctrl_get(struct gud_drm_gadget *gdg, u8 request,
+ u16 index, void *data, size_t size);
+int gud_drm_gadget_ctrl_set(struct gud_drm_gadget *gdg, u8 request,
+ u16 index, void *data, size_t size);
+int gud_drm_gadget_set_buffer(struct gud_drm_gadget *gdg, struct gud_drm_req_set_buffer *req);
+int gud_drm_gadget_write_buffer(struct gud_drm_gadget *gdg, const void *buf, size_t len);
+
#endif
--
2.23.0