On Fri, Feb 21, 2025 at 11:37:57AM +0000, Aditya Garg wrote: > From: Kerem Karabay <kekrby@xxxxxxxxx> > > The Touch Bars found on x86 Macs support two USB configurations: one > where the device presents itself as a HID keyboard and can display > predefined sets of keys, and one where the operating system has full > control over what is displayed. > > This commit adds support for the display functionality of the second > configuration. Functionality for the first configuration has been > merged in the HID tree. > > Note that this driver has only been tested on T2 Macs, and only includes > the USB device ID for these devices. Testing on T1 Macs would be > appreciated. > > Credit goes to Ben (Bingxing) Wang on GitHub [1] for reverse engineering > most of the protocol. > > [1]: https://github.com/imbushuo/DFRDisplayKm Use Link tag for this. > +config DRM_APPLETBDRM > + tristate "DRM support for Apple Touch Bars" > + depends on DRM && USB && MMU I dunno if tiny is not only about SPI panels, would be nice to hear somebody from DRM to confirm that USB ones are okay to have. > + select DRM_GEM_SHMEM_HELPER > + select DRM_KMS_HELPER > + select HID_APPLETB_BL > + select HID_MULTITOUCH > + help > + Say Y here if you want support for the display of Touch Bars on x86 > + MacBook Pros. > + > + To compile this driver as a module, choose M here: the > + module will be called appletbdrm. ... > +/* > + * Apple Touch Bar DRM Driver > + * > + * Copyright (c) 2023 Kerem Karabay <kekrby@xxxxxxxxx> No changes in 2024/2025? > + */ ... > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt Why? Don't you have a struct device available? ... > +#include <linux/module.h> > +#include <linux/unaligned.h> > +#include <linux/usb.h> This is way too little list of what you are actually using, please consider IWYU principle in place. ... > +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3])) Reinventing a wheel from get_unaligned_be32() AFAICS. ... > +#define drm_to_adev(_drm) container_of(_drm, struct appletbdrm_device, drm) + container_of.h ... > +struct appletbdrm_msg_request_header { > + __le16 unk_00; + types.h > + __le16 unk_02; > + __le32 unk_04; > + __le32 unk_08; > + __le32 size; > +} __packed; Why __packed? Please explain and justify for all the data types that are marked with this attribute. ... > +static int appletbdrm_send_request(struct appletbdrm_device *adev, > + struct appletbdrm_msg_request_header *request, size_t size) > +{ > + struct usb_device *udev = adev_to_udev(adev); > + struct drm_device *drm = &adev->drm; > + int ret, actual_size; > + > + ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, adev->out_ep), > + request, size, &actual_size, APPLETBDRM_BULK_MSG_TIMEOUT); > + if (ret) { > + drm_err(drm, "Failed to send message (%d)\n", ret); > + return ret; > + } > + > + if (actual_size != size) { > + drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n", > + actual_size, size); > + return -EIO; > + } > + > + return ret; return 0; Or you are expecting something else here? > +} ... > +static int appletbdrm_read_response(struct appletbdrm_device *adev, > + struct appletbdrm_msg_response_header *response, > + size_t size, u32 expected_response) > +{ > + struct usb_device *udev = adev_to_udev(adev); > + struct drm_device *drm = &adev->drm; > + int ret, actual_size; > + bool readiness_signal_received = false; > + > +retry: > + ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, adev->in_ep), > + response, size, &actual_size, APPLETBDRM_BULK_MSG_TIMEOUT); > + if (ret) { > + drm_err(drm, "Failed to read response (%d)\n", ret); > + return ret; > + } > + > + /* > + * The device responds to the first request sent in a particular > + * timeframe after the USB device configuration is set with a readiness > + * signal, in which case the response should be read again > + */ > + if (response->msg == APPLETBDRM_MSG_SIGNAL_READINESS) { > + if (!readiness_signal_received) { > + readiness_signal_received = true; > + goto retry; > + } > + > + drm_err(drm, "Encountered unexpected readiness signal\n"); > + return -EIO; > + } > + > + if (actual_size != size) { > + drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n", > + actual_size, size); > + return -EIO; > + } > + > + if (response->msg != expected_response) { > + drm_err(drm, "Unexpected response from device (expected %p4ch found %p4ch)\n", > + &expected_response, &response->msg); > + return -EIO; For three different cases the same error code, can it be adjusted more to the situation? > + } > + > + return 0; > +} > +static int appletbdrm_send_msg(struct appletbdrm_device *adev, u32 msg) > +{ > + struct appletbdrm_msg_simple_request *request; > + int ret; > + > + request = kzalloc(sizeof(*request), GFP_KERNEL); + slab.h > + if (!request) > + return -ENOMEM; + err.h > + > + request->header.unk_00 = cpu_to_le16(2); > + request->header.unk_02 = cpu_to_le16(0x1512); > + request->header.size = cpu_to_le32(sizeof(*request) - sizeof(request->header)); > + request->msg = msg; > + request->size = request->header.size; > + > + ret = appletbdrm_send_request(adev, &request->header, sizeof(*request)); > + > + kfree(request); > + > + return ret; > +} ... > + return drm_rect_width(rect) * drm_rect_height(rect) * (APPLETBDRM_BITS_PER_PIXEL / 8); BITS_TO_BYTES() ? Will need bits.h IIRC. ... > +static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane, > + struct drm_atomic_state *state) > +{ > + struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane); > + struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane); > + struct drm_crtc *new_crtc = new_plane_state->crtc; > + struct drm_crtc_state *new_crtc_state = NULL; > + struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(new_plane_state); > + struct drm_atomic_helper_damage_iter iter; > + struct drm_rect damage; > + size_t frames_size = 0; > + size_t request_size; > + int ret; > + > + if (new_crtc) > + new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc); > + > + ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state, > + DRM_PLANE_NO_SCALING, > + DRM_PLANE_NO_SCALING, > + false, false); > + if (ret) > + return ret; > + else if (!new_plane_state->visible) Why 'else'? It's redundant. > + return 0; > + > + drm_atomic_helper_damage_iter_init(&iter, old_plane_state, new_plane_state); > + drm_atomic_for_each_plane_damage(&iter, &damage) { > + frames_size += struct_size((struct appletbdrm_frame *)0, buf, rect_size(&damage)); > + } > + > + if (!frames_size) > + return 0; > + > + request_size = ALIGN(sizeof(struct appletbdrm_fb_request) + > + frames_size + > + sizeof(struct appletbdrm_fb_request_footer), 16); Missing header for ALIGN(). But have you checked overflow.h for the possibility of using some helper macros from there? This is what should be usually done for k*alloc() in the kernel. > + appletbdrm_state->request = kzalloc(request_size, GFP_KERNEL); > + > + if (!appletbdrm_state->request) > + return -ENOMEM; > + > + appletbdrm_state->response = kzalloc(sizeof(*appletbdrm_state->response), GFP_KERNEL); > + > + if (!appletbdrm_state->response) > + return -ENOMEM; > + > + appletbdrm_state->request_size = request_size; > + appletbdrm_state->frames_size = frames_size; > + > + return 0; > +} ... > +static int appletbdrm_flush_damage(struct appletbdrm_device *adev, > + struct drm_plane_state *old_state, > + struct drm_plane_state *state) > +{ > + struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(state); > + struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state); > + struct appletbdrm_fb_request_response *response = appletbdrm_state->response; > + struct appletbdrm_fb_request_footer *footer; > + struct drm_atomic_helper_damage_iter iter; > + struct drm_framebuffer *fb = state->fb; > + struct appletbdrm_fb_request *request = appletbdrm_state->request; > + struct drm_device *drm = &adev->drm; > + struct appletbdrm_frame *frame; > + u64 timestamp = ktime_get_ns(); > + struct drm_rect damage; > + size_t frames_size = appletbdrm_state->frames_size; > + size_t request_size = appletbdrm_state->request_size; > + int ret; > + > + if (!frames_size) > + return 0; > + > + ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE); > + if (ret) { > + drm_err(drm, "Failed to start CPU framebuffer access (%d)\n", ret); > + goto end_fb_cpu_access; Strange. Is it for real that this API requires to be called in both cases for success and for an error? > + } > + > + request->header.unk_00 = cpu_to_le16(2); > + request->header.unk_02 = cpu_to_le16(0x12); > + request->header.unk_04 = cpu_to_le32(9); > + request->header.size = cpu_to_le32(request_size - sizeof(request->header)); > + request->unk_10 = cpu_to_le16(1); > + request->msg_id = timestamp & 0xff; Why ' & 0xff'? > + frame = (struct appletbdrm_frame *)request->data; > + > + drm_atomic_helper_damage_iter_init(&iter, old_state, state); > + drm_atomic_for_each_plane_damage(&iter, &damage) { > + struct drm_rect dst_clip = state->dst; > + struct iosys_map dst = IOSYS_MAP_INIT_VADDR(frame->buf); > + u32 buf_size = rect_size(&damage); > + > + if (!drm_rect_intersect(&dst_clip, &damage)) > + continue; > + > + /* > + * The coordinates need to be translated to the coordinate > + * system the device expects, see the comment in > + * appletbdrm_setup_mode_config > + */ > + frame->begin_x = cpu_to_le16(damage.y1); > + frame->begin_y = cpu_to_le16(adev->height - damage.x2); > + frame->width = cpu_to_le16(drm_rect_height(&damage)); > + frame->height = cpu_to_le16(drm_rect_width(&damage)); > + frame->buf_size = cpu_to_le32(buf_size); > + > + switch (fb->format->format) { > + case DRM_FORMAT_XRGB8888: > + drm_fb_xrgb8888_to_bgr888(&dst, NULL, &shadow_plane_state->data[0], fb, &damage, &shadow_plane_state->fmtcnv_state); > + break; > + default: > + drm_fb_memcpy(&dst, NULL, &shadow_plane_state->data[0], fb, &damage); > + break; > + } > + > + frame = (void *)frame + struct_size(frame, buf, buf_size); + overflow.h > + } > + > + footer = (struct appletbdrm_fb_request_footer *)&request->data[frames_size]; > + > + footer->unk_0c = cpu_to_le32(0xfffe); > + footer->unk_1c = cpu_to_le32(0x80001); > + footer->unk_34 = cpu_to_le32(0x80002); > + footer->unk_4c = cpu_to_le32(0xffff); > + footer->timestamp = cpu_to_le64(timestamp); > + > + ret = appletbdrm_send_request(adev, &request->header, request_size); > + if (ret) > + goto end_fb_cpu_access; > + > + ret = appletbdrm_read_response(adev, &response->header, sizeof(*response), > + APPLETBDRM_MSG_UPDATE_COMPLETE); > + if (ret) > + goto end_fb_cpu_access; > + > + if (response->timestamp != footer->timestamp) { > + drm_err(drm, "Response timestamp (%llu) doesn't match request timestamp (%llu)\n", > + le64_to_cpu(response->timestamp), timestamp); > + goto end_fb_cpu_access; > + } > + > +end_fb_cpu_access: > + drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE); > + > + return ret; > +} ... > +static void appletbdrm_primary_plane_reset(struct drm_plane *plane) > +{ > + struct appletbdrm_plane_state *appletbdrm_state; > + > + WARN_ON(plane->state); + bug.h > + appletbdrm_state = kzalloc(sizeof(*appletbdrm_state), GFP_KERNEL); > + if (!appletbdrm_state) > + return; > + > + __drm_gem_reset_shadow_plane(plane, &appletbdrm_state->base); > +} ... > +static int appletbdrm_setup_mode_config(struct appletbdrm_device *adev) > +{ > + struct drm_connector *connector = &adev->connector; > + struct drm_plane *primary_plane; > + struct drm_crtc *crtc; > + struct drm_encoder *encoder; > + struct drm_device *drm = &adev->drm; > + struct device *dev = adev->dev; > + int ret; > + > + ret = drmm_mode_config_init(drm); > + if (ret) > + return dev_err_probe(dev, ret, "Failed to initialize mode configuration\n"); + dev_printk.h > + primary_plane = &adev->primary_plane; > + ret = drm_universal_plane_init(drm, primary_plane, 0, > + &appletbdrm_primary_plane_funcs, > + appletbdrm_primary_plane_formats, > + ARRAY_SIZE(appletbdrm_primary_plane_formats), + array_size.h > + NULL, > + DRM_PLANE_TYPE_PRIMARY, NULL); > + if (ret) > + return dev_err_probe(dev, ret, "Failed to initialize universal plane object\n"); > + drm_plane_helper_add(primary_plane, &appletbdrm_primary_plane_helper_funcs); > + drm_plane_enable_fb_damage_clips(primary_plane); > + > + crtc = &adev->crtc; > + ret = drm_crtc_init_with_planes(drm, crtc, primary_plane, NULL, > + &appletbdrm_crtc_funcs, NULL); > + if (ret) > + return dev_err_probe(dev, ret, "Failed to initialize CRTC object\n"); > + drm_crtc_helper_add(crtc, &appletbdrm_crtc_helper_funcs); > + > + encoder = &adev->encoder; > + ret = drm_encoder_init(drm, encoder, &appletbdrm_encoder_funcs, > + DRM_MODE_ENCODER_DAC, NULL); > + if (ret) > + return dev_err_probe(dev, ret, "Failed to initialize encoder\n"); > + encoder->possible_crtcs = drm_crtc_mask(crtc); > + > + /* > + * The coordinate system used by the device is different from the > + * coordinate system of the framebuffer in that the x and y axes are > + * swapped, and that the y axis is inverted; so what the device reports > + * as the height is actually the width of the framebuffer and vice > + * versa > + */ > + drm->mode_config.min_width = 0; > + drm->mode_config.min_height = 0; > + drm->mode_config.max_width = max(adev->height, DRM_SHADOW_PLANE_MAX_WIDTH); > + drm->mode_config.max_height = max(adev->width, DRM_SHADOW_PLANE_MAX_HEIGHT); > + drm->mode_config.preferred_depth = APPLETBDRM_BITS_PER_PIXEL; > + drm->mode_config.funcs = &appletbdrm_mode_config_funcs; > + > + adev->mode = (struct drm_display_mode) { Why do you need a compound literal here? Perhaps you want to have that to be done directly in DRM_MODE_INIT()? > + DRM_MODE_INIT(60, adev->height, adev->width, > + DRM_MODE_RES_MM(adev->height, 218), > + DRM_MODE_RES_MM(adev->width, 218)) > + }; > + > + ret = drm_connector_init(drm, connector, > + &appletbdrm_connector_funcs, DRM_MODE_CONNECTOR_USB); > + if (ret) > + return dev_err_probe(dev, ret, "Failed to initialize connector\n"); > + > + drm_connector_helper_add(connector, &appletbdrm_connector_helper_funcs); > + > + ret = drm_connector_set_panel_orientation(connector, > + DRM_MODE_PANEL_ORIENTATION_RIGHT_UP); > + if (ret) > + return dev_err_probe(dev, ret, "Failed to set panel orientation\n"); > + > + connector->display_info.non_desktop = true; > + ret = drm_object_property_set_value(&connector->base, > + drm->mode_config.non_desktop_property, true); > + if (ret) > + return dev_err_probe(dev, ret, "Failed to set non-desktop property\n"); > + > + ret = drm_connector_attach_encoder(connector, encoder); > + > + if (ret) > + return dev_err_probe(dev, ret, "Failed to initialize simple display pipe\n"); > + > + drm_mode_config_reset(drm); > + > + return 0; > +} -- With Best Regards, Andy Shevchenko
