root/drivers/gpu/drm/gud/gud_drv.c
// SPDX-License-Identifier: MIT
/*
 * Copyright 2020 Noralf Trønnes
 */

#include <linux/dma-buf.h>
#include <linux/dma-mapping.h>
#include <linux/lz4.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/string_helpers.h>
#include <linux/usb.h>
#include <linux/vmalloc.h>
#include <linux/workqueue.h>

#include <drm/clients/drm_client_setup.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_blend.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_damage_helper.h>
#include <drm/drm_debugfs.h>
#include <drm/drm_drv.h>
#include <drm/drm_fbdev_shmem.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_gem_atomic_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_gem_shmem_helper.h>
#include <drm/drm_managed.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>
#include <drm/gud.h>

#include "gud_internal.h"

/* Only used internally */
static const struct drm_format_info gud_drm_format_r1 = {
        .format = GUD_DRM_FORMAT_R1,
        .num_planes = 1,
        .char_per_block = { 1, 0, 0 },
        .block_w = { 8, 0, 0 },
        .block_h = { 1, 0, 0 },
        .hsub = 1,
        .vsub = 1,
};

static const struct drm_format_info gud_drm_format_xrgb1111 = {
        .format = GUD_DRM_FORMAT_XRGB1111,
        .num_planes = 1,
        .char_per_block = { 1, 0, 0 },
        .block_w = { 2, 0, 0 },
        .block_h = { 1, 0, 0 },
        .hsub = 1,
        .vsub = 1,
};

static int gud_usb_control_msg(struct usb_interface *intf, bool in,
                               u8 request, u16 value, void *buf, size_t len)
{
        u8 requesttype = USB_TYPE_VENDOR | USB_RECIP_INTERFACE;
        u8 ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
        struct usb_device *usb = interface_to_usbdev(intf);
        unsigned int pipe;

        if (len && !buf)
                return -EINVAL;

        if (in) {
                pipe = usb_rcvctrlpipe(usb, 0);
                requesttype |= USB_DIR_IN;
        } else {
                pipe = usb_sndctrlpipe(usb, 0);
                requesttype |= USB_DIR_OUT;
        }

        return usb_control_msg(usb, pipe, request, requesttype, value,
                               ifnum, buf, len, USB_CTRL_GET_TIMEOUT);
}

static int gud_get_display_descriptor(struct usb_interface *intf,
                                      struct gud_display_descriptor_req *desc)
{
        void *buf;
        int ret;

        buf = kmalloc_obj(*desc);
        if (!buf)
                return -ENOMEM;

        ret = gud_usb_control_msg(intf, true, GUD_REQ_GET_DESCRIPTOR, 0, buf, sizeof(*desc));
        memcpy(desc, buf, sizeof(*desc));
        kfree(buf);
        if (ret < 0)
                return ret;
        if (ret != sizeof(*desc))
                return -EIO;

        if (desc->magic != le32_to_cpu(GUD_DISPLAY_MAGIC))
                return -ENODATA;

        DRM_DEV_DEBUG_DRIVER(&intf->dev,
                             "version=%u flags=0x%x compression=0x%x max_buffer_size=%u\n",
                             desc->version, le32_to_cpu(desc->flags), desc->compression,
                             le32_to_cpu(desc->max_buffer_size));

        if (!desc->version || !desc->max_width || !desc->max_height ||
            le32_to_cpu(desc->min_width) > le32_to_cpu(desc->max_width) ||
            le32_to_cpu(desc->min_height) > le32_to_cpu(desc->max_height))
                return -EINVAL;

        return 0;
}

static int gud_status_to_errno(u8 status)
{
        switch (status) {
        case GUD_STATUS_OK:
                return 0;
        case GUD_STATUS_BUSY:
                return -EBUSY;
        case GUD_STATUS_REQUEST_NOT_SUPPORTED:
                return -EOPNOTSUPP;
        case GUD_STATUS_PROTOCOL_ERROR:
                return -EPROTO;
        case GUD_STATUS_INVALID_PARAMETER:
                return -EINVAL;
        case GUD_STATUS_ERROR:
                return -EREMOTEIO;
        default:
                return -EREMOTEIO;
        }
}

static int gud_usb_get_status(struct usb_interface *intf)
{
        int ret, status = -EIO;
        u8 *buf;

        buf = kmalloc_obj(*buf);
        if (!buf)
                return -ENOMEM;

        ret = gud_usb_control_msg(intf, true, GUD_REQ_GET_STATUS, 0, buf, sizeof(*buf));
        if (ret == sizeof(*buf))
                status = gud_status_to_errno(*buf);
        kfree(buf);

        if (ret < 0)
                return ret;

        return status;
}

static int gud_usb_transfer(struct gud_device *gdrm, bool in, u8 request, u16 index,
                            void *buf, size_t len)
{
        struct usb_interface *intf = to_usb_interface(gdrm->drm.dev);
        int idx, ret;

        drm_dbg(&gdrm->drm, "%s: request=0x%x index=%u len=%zu\n",
                in ? "get" : "set", request, index, len);

        if (!drm_dev_enter(&gdrm->drm, &idx))
                return -ENODEV;

        mutex_lock(&gdrm->ctrl_lock);

        ret = gud_usb_control_msg(intf, in, request, index, buf, len);
        if (ret == -EPIPE || ((gdrm->flags & GUD_DISPLAY_FLAG_STATUS_ON_SET) && !in && ret >= 0)) {
                int status;

                status = gud_usb_get_status(intf);
                if (status < 0) {
                        ret = status;
                } else if (ret < 0) {
                        dev_err_once(gdrm->drm.dev,
                                     "Unexpected status OK for failed transfer\n");
                        ret = -EPIPE;
                }
        }

        if (ret < 0) {
                drm_dbg(&gdrm->drm, "ret=%d\n", ret);
                gdrm->stats_num_errors++;
        }

        mutex_unlock(&gdrm->ctrl_lock);
        drm_dev_exit(idx);

        return ret;
}

/*
 * @buf cannot be allocated on the stack.
 * Returns number of bytes received or negative error code on failure.
 */
int gud_usb_get(struct gud_device *gdrm, u8 request, u16 index, void *buf, size_t max_len)
{
        return gud_usb_transfer(gdrm, true, request, index, buf, max_len);
}

/*
 * @buf can be allocated on the stack or NULL.
 * Returns zero on success or negative error code on failure.
 */
int gud_usb_set(struct gud_device *gdrm, u8 request, u16 index, void *buf, size_t len)
{
        void *trbuf = NULL;
        int ret;

        if (buf && len) {
                trbuf = kmemdup(buf, len, GFP_KERNEL);
                if (!trbuf)
                        return -ENOMEM;
        }

        ret = gud_usb_transfer(gdrm, false, request, index, trbuf, len);
        kfree(trbuf);
        if (ret < 0)
                return ret;

        return ret != len ? -EIO : 0;
}

/*
 * @val can be allocated on the stack.
 * Returns zero on success or negative error code on failure.
 */
int gud_usb_get_u8(struct gud_device *gdrm, u8 request, u16 index, u8 *val)
{
        u8 *buf;
        int ret;

        buf = kmalloc(sizeof(*val), GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        ret = gud_usb_get(gdrm, request, index, buf, sizeof(*val));
        *val = *buf;
        kfree(buf);
        if (ret < 0)
                return ret;

        return ret != sizeof(*val) ? -EIO : 0;
}

/* Returns zero on success or negative error code on failure. */
int gud_usb_set_u8(struct gud_device *gdrm, u8 request, u8 val)
{
        return gud_usb_set(gdrm, request, 0, &val, sizeof(val));
}

static int gud_plane_add_properties(struct gud_device *gdrm)
{
        struct gud_property_req *properties;
        unsigned int i, num_properties;
        int ret;

        properties = kzalloc_objs(*properties, GUD_PROPERTIES_MAX_NUM);
        if (!properties)
                return -ENOMEM;

        ret = gud_usb_get(gdrm, GUD_REQ_GET_PROPERTIES, 0,
                          properties, GUD_PROPERTIES_MAX_NUM * sizeof(*properties));
        if (ret <= 0)
                goto out;
        if (ret % sizeof(*properties)) {
                ret = -EIO;
                goto out;
        }

        num_properties = ret / sizeof(*properties);
        ret = 0;

        gdrm->properties = drmm_kcalloc(&gdrm->drm, num_properties, sizeof(*gdrm->properties),
                                        GFP_KERNEL);
        if (!gdrm->properties) {
                ret = -ENOMEM;
                goto out;
        }

        for (i = 0; i < num_properties; i++) {
                u16 prop = le16_to_cpu(properties[i].prop);
                u64 val = le64_to_cpu(properties[i].val);

                switch (prop) {
                case GUD_PROPERTY_ROTATION:
                        /*
                         * DRM UAPI matches the protocol so use the value directly,
                         * but mask out any additions on future devices.
                         */
                        val &= GUD_ROTATION_MASK;
                        ret = drm_plane_create_rotation_property(&gdrm->plane,
                                                                 DRM_MODE_ROTATE_0, val);
                        break;
                default:
                        /* New ones might show up in future devices, skip those we don't know. */
                        drm_dbg(&gdrm->drm, "Ignoring unknown property: %u\n", prop);
                        continue;
                }

                if (ret)
                        goto out;

                gdrm->properties[gdrm->num_properties++] = prop;
        }
out:
        kfree(properties);

        return ret;
}

static int gud_stats_debugfs(struct seq_file *m, void *data)
{
        struct drm_debugfs_entry *entry = m->private;
        struct gud_device *gdrm = to_gud_device(entry->dev);
        char buf[10];

        string_get_size(gdrm->bulk_len, 1, STRING_UNITS_2, buf, sizeof(buf));
        seq_printf(m, "Max buffer size: %s\n", buf);
        seq_printf(m, "Number of errors:  %u\n", gdrm->stats_num_errors);

        seq_puts(m, "Compression:      ");
        if (gdrm->compression & GUD_COMPRESSION_LZ4)
                seq_puts(m, " lz4");
        if (!gdrm->compression)
                seq_puts(m, " none");
        seq_puts(m, "\n");

        if (gdrm->compression) {
                u64 remainder;
                u64 ratio = div64_u64_rem(gdrm->stats_length, gdrm->stats_actual_length,
                                          &remainder);
                u64 ratio_frac = div64_u64(remainder * 10, gdrm->stats_actual_length);

                seq_printf(m, "Compression ratio: %llu.%llu\n", ratio, ratio_frac);
        }

        return 0;
}

static const struct drm_crtc_helper_funcs gud_crtc_helper_funcs = {
        .atomic_check = drm_crtc_helper_atomic_check,
        .atomic_enable = gud_crtc_atomic_enable,
        .atomic_disable = gud_crtc_atomic_disable,
};

static const struct drm_crtc_funcs gud_crtc_funcs = {
        .reset = drm_atomic_helper_crtc_reset,
        .destroy = drm_crtc_cleanup,
        .set_config = drm_atomic_helper_set_config,
        .page_flip = drm_atomic_helper_page_flip,
        .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
        .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
};

static const struct drm_plane_helper_funcs gud_plane_helper_funcs = {
        DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
        .atomic_check = gud_plane_atomic_check,
        .atomic_update = gud_plane_atomic_update,
};

static const struct drm_plane_funcs gud_plane_funcs = {
        .update_plane = drm_atomic_helper_update_plane,
        .disable_plane = drm_atomic_helper_disable_plane,
        .destroy = drm_plane_cleanup,
        DRM_GEM_SHADOW_PLANE_FUNCS,
};

static const struct drm_mode_config_helper_funcs gud_mode_config_helpers = {
        .atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
};

static const struct drm_mode_config_funcs gud_mode_config_funcs = {
        .fb_create = drm_gem_fb_create_with_dirty,
        .atomic_check = drm_atomic_helper_check,
        .atomic_commit = drm_atomic_helper_commit,
};

static const u64 gud_plane_modifiers[] = {
        DRM_FORMAT_MOD_LINEAR,
        DRM_FORMAT_MOD_INVALID
};

DEFINE_DRM_GEM_FOPS(gud_fops);

static const struct drm_driver gud_drm_driver = {
        .driver_features        = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
        .fops                   = &gud_fops,
        DRM_GEM_SHMEM_DRIVER_OPS,
        DRM_FBDEV_SHMEM_DRIVER_OPS,

        .name                   = "gud",
        .desc                   = "Generic USB Display",
        .major                  = 1,
        .minor                  = 0,
};

static int gud_alloc_bulk_buffer(struct gud_device *gdrm)
{
        unsigned int i, num_pages;
        struct page **pages;
        void *ptr;
        int ret;

        gdrm->bulk_buf = vmalloc_32(gdrm->bulk_len);
        if (!gdrm->bulk_buf)
                return -ENOMEM;

        num_pages = DIV_ROUND_UP(gdrm->bulk_len, PAGE_SIZE);
        pages = kmalloc_objs(struct page *, num_pages);
        if (!pages)
                return -ENOMEM;

        for (i = 0, ptr = gdrm->bulk_buf; i < num_pages; i++, ptr += PAGE_SIZE)
                pages[i] = vmalloc_to_page(ptr);

        ret = sg_alloc_table_from_pages(&gdrm->bulk_sgt, pages, num_pages,
                                        0, gdrm->bulk_len, GFP_KERNEL);
        kfree(pages);

        return ret;
}

static void gud_free_buffers_and_mutex(void *data)
{
        struct gud_device *gdrm = data;

        vfree(gdrm->compress_buf);
        gdrm->compress_buf = NULL;
        sg_free_table(&gdrm->bulk_sgt);
        vfree(gdrm->bulk_buf);
        gdrm->bulk_buf = NULL;
        mutex_destroy(&gdrm->ctrl_lock);
}

static int gud_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
        const struct drm_format_info *xrgb8888_emulation_format = NULL;
        bool rgb565_supported = false, xrgb8888_supported = false;
        unsigned int num_formats_dev, num_formats = 0;
        struct usb_endpoint_descriptor *bulk_out;
        struct gud_display_descriptor_req desc;
        struct device *dev = &intf->dev;
        size_t max_buffer_size = 0;
        struct gud_device *gdrm;
        struct drm_device *drm;
        struct device *dma_dev;
        u8 *formats_dev;
        u32 *formats;
        int ret, i;

        ret = usb_find_bulk_out_endpoint(intf->cur_altsetting, &bulk_out);
        if (ret)
                return ret;

        ret = gud_get_display_descriptor(intf, &desc);
        if (ret) {
                DRM_DEV_DEBUG_DRIVER(dev, "Not a display interface: ret=%d\n", ret);
                return -ENODEV;
        }

        if (desc.version > 1) {
                dev_err(dev, "Protocol version %u is not supported\n", desc.version);
                return -ENODEV;
        }

        gdrm = devm_drm_dev_alloc(dev, &gud_drm_driver, struct gud_device, drm);
        if (IS_ERR(gdrm))
                return PTR_ERR(gdrm);

        drm = &gdrm->drm;

        gdrm->flags = le32_to_cpu(desc.flags);
        gdrm->compression = desc.compression & GUD_COMPRESSION_LZ4;

        if (gdrm->flags & GUD_DISPLAY_FLAG_FULL_UPDATE && gdrm->compression)
                return -EINVAL;

        mutex_init(&gdrm->ctrl_lock);
        mutex_init(&gdrm->damage_lock);
        INIT_WORK(&gdrm->work, gud_flush_work);
        gud_clear_damage(gdrm);

        ret = devm_add_action(dev, gud_free_buffers_and_mutex, gdrm);
        if (ret)
                return ret;

        usb_set_intfdata(intf, gdrm);

        dma_dev = usb_intf_get_dma_device(intf);
        if (dma_dev) {
                drm_dev_set_dma_dev(drm, dma_dev);
                put_device(dma_dev);
        } else {
                dev_warn(dev, "buffer sharing not supported"); /* not an error */
        }

        /* Mode config init */
        ret = drmm_mode_config_init(drm);
        if (ret)
                return ret;

        drm->mode_config.min_width = le32_to_cpu(desc.min_width);
        drm->mode_config.max_width = le32_to_cpu(desc.max_width);
        drm->mode_config.min_height = le32_to_cpu(desc.min_height);
        drm->mode_config.max_height = le32_to_cpu(desc.max_height);
        drm->mode_config.funcs = &gud_mode_config_funcs;
        drm->mode_config.helper_private = &gud_mode_config_helpers;

        /* Format init */
        formats_dev = devm_kmalloc(dev, GUD_FORMATS_MAX_NUM, GFP_KERNEL);
        /* Add room for emulated XRGB8888 */
        formats = devm_kmalloc_array(dev, GUD_FORMATS_MAX_NUM + 1, sizeof(*formats), GFP_KERNEL);
        if (!formats_dev || !formats)
                return -ENOMEM;

        ret = gud_usb_get(gdrm, GUD_REQ_GET_FORMATS, 0, formats_dev, GUD_FORMATS_MAX_NUM);
        if (ret < 0)
                return ret;

        num_formats_dev = ret;
        for (i = 0; i < num_formats_dev; i++) {
                const struct drm_format_info *info;
                size_t fmt_buf_size;
                u32 format;

                format = gud_to_fourcc(formats_dev[i]);
                if (!format) {
                        drm_dbg(drm, "Unsupported format: 0x%02x\n", formats_dev[i]);
                        continue;
                }

                if (format == GUD_DRM_FORMAT_R1)
                        info = &gud_drm_format_r1;
                else if (format == GUD_DRM_FORMAT_XRGB1111)
                        info = &gud_drm_format_xrgb1111;
                else
                        info = drm_format_info(format);

                switch (format) {
                case GUD_DRM_FORMAT_R1:
                        fallthrough;
                case DRM_FORMAT_R8:
                        fallthrough;
                case GUD_DRM_FORMAT_XRGB1111:
                        fallthrough;
                case DRM_FORMAT_RGB332:
                        fallthrough;
                case DRM_FORMAT_RGB888:
                        if (!xrgb8888_emulation_format)
                                xrgb8888_emulation_format = info;
                        break;
                case DRM_FORMAT_RGB565:
                        rgb565_supported = true;
                        if (!xrgb8888_emulation_format)
                                xrgb8888_emulation_format = info;
                        break;
                case DRM_FORMAT_XRGB8888:
                        xrgb8888_supported = true;
                        break;
                }

                fmt_buf_size = drm_format_info_min_pitch(info, 0, drm->mode_config.max_width) *
                               drm->mode_config.max_height;
                max_buffer_size = max(max_buffer_size, fmt_buf_size);

                if (format == GUD_DRM_FORMAT_R1 || format == GUD_DRM_FORMAT_XRGB1111)
                        continue; /* Internal not for userspace */

                formats[num_formats++] = format;
        }

        if (!num_formats && !xrgb8888_emulation_format) {
                dev_err(dev, "No supported pixel formats found\n");
                return -EINVAL;
        }

        /* Prefer speed over color depth */
        if (rgb565_supported)
                drm->mode_config.preferred_depth = 16;

        if (!xrgb8888_supported && xrgb8888_emulation_format) {
                gdrm->xrgb8888_emulation_format = xrgb8888_emulation_format;
                formats[num_formats++] = DRM_FORMAT_XRGB8888;
        }

        if (desc.max_buffer_size)
                max_buffer_size = le32_to_cpu(desc.max_buffer_size);
        /* Prevent a misbehaving device from allocating loads of RAM. 4096x4096@XRGB8888 = 64 MB */
        if (max_buffer_size > SZ_64M)
                max_buffer_size = SZ_64M;

        gdrm->bulk_pipe = usb_sndbulkpipe(interface_to_usbdev(intf), usb_endpoint_num(bulk_out));
        gdrm->bulk_len = max_buffer_size;

        ret = gud_alloc_bulk_buffer(gdrm);
        if (ret)
                return ret;

        if (gdrm->compression & GUD_COMPRESSION_LZ4) {
                gdrm->lz4_comp_mem = devm_kmalloc(dev, LZ4_MEM_COMPRESS, GFP_KERNEL);
                if (!gdrm->lz4_comp_mem)
                        return -ENOMEM;

                gdrm->compress_buf = vmalloc(gdrm->bulk_len);
                if (!gdrm->compress_buf)
                        return -ENOMEM;
        }

        /* Pipeline init */
        ret = drm_universal_plane_init(drm, &gdrm->plane, 0,
                                       &gud_plane_funcs,
                                       formats, num_formats,
                                       gud_plane_modifiers,
                                       DRM_PLANE_TYPE_PRIMARY, NULL);
        if (ret)
                return ret;

        drm_plane_helper_add(&gdrm->plane, &gud_plane_helper_funcs);
        drm_plane_enable_fb_damage_clips(&gdrm->plane);

        ret = gud_plane_add_properties(gdrm);
        if (ret) {
                dev_err(dev, "Failed to add properties (error=%d)\n", ret);
                return ret;
        }

        ret = drm_crtc_init_with_planes(drm, &gdrm->crtc, &gdrm->plane, NULL,
                                        &gud_crtc_funcs, NULL);
        if (ret)
                return ret;

        drm_crtc_helper_add(&gdrm->crtc, &gud_crtc_helper_funcs);

        ret = gud_get_connectors(gdrm);
        if (ret) {
                dev_err(dev, "Failed to get connectors (error=%d)\n", ret);
                return ret;
        }

        drm_mode_config_reset(drm);
        drm_kms_helper_poll_init(drm);

        drm_debugfs_add_file(drm, "stats", gud_stats_debugfs, NULL);

        ret = drm_dev_register(drm, 0);
        if (ret)
                return ret;

        devm_kfree(dev, formats);
        devm_kfree(dev, formats_dev);

        drm_client_setup(drm, NULL);

        return 0;
}

static void gud_disconnect(struct usb_interface *interface)
{
        struct gud_device *gdrm = usb_get_intfdata(interface);
        struct drm_device *drm = &gdrm->drm;

        drm_kms_helper_poll_fini(drm);
        drm_dev_unplug(drm);
        drm_atomic_helper_shutdown(drm);
}

static int gud_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct gud_device *gdrm = usb_get_intfdata(intf);

        return drm_mode_config_helper_suspend(&gdrm->drm);
}

static int gud_resume(struct usb_interface *intf)
{
        struct gud_device *gdrm = usb_get_intfdata(intf);

        drm_mode_config_helper_resume(&gdrm->drm);

        return 0;
}

static const struct usb_device_id gud_id_table[] = {
        { USB_DEVICE_INTERFACE_CLASS(0x1d50, 0x614d, USB_CLASS_VENDOR_SPEC) },
        { USB_DEVICE_INTERFACE_CLASS(0x16d0, 0x10a9, USB_CLASS_VENDOR_SPEC) },
        { }
};

MODULE_DEVICE_TABLE(usb, gud_id_table);

static struct usb_driver gud_usb_driver = {
        .name           = "gud",
        .probe          = gud_probe,
        .disconnect     = gud_disconnect,
        .id_table       = gud_id_table,
        .suspend        = gud_suspend,
        .resume         = gud_resume,
        .reset_resume   = gud_resume,
};

module_usb_driver(gud_usb_driver);

MODULE_AUTHOR("Noralf Trønnes");
MODULE_DESCRIPTION("GUD USB Display driver");
MODULE_LICENSE("Dual MIT/GPL");