// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2019 Intel Corporation.
 *
 * Authors:
 * Ramalingam C <ramalingam.c@intel.com>
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/firmware.h>

#include <drm/display/drm_hdcp_helper.h>
#include <drm/drm_sysfs.h>
#include <drm/drm_print.h>
#include <drm/drm_device.h>
#include <drm/drm_property.h>
#include <drm/drm_mode_object.h>
#include <drm/drm_connector.h>

static inline void drm_hdcp_print_ksv(const u8 *ksv)
{
        DRM_DEBUG("\t%#02x, %#02x, %#02x, %#02x, %#02x\n",
                  ksv[0], ksv[1], ksv[2], ksv[3], ksv[4]);
}

static u32 drm_hdcp_get_revoked_ksv_count(const u8 *buf, u32 vrls_length)
{
        u32 parsed_bytes = 0, ksv_count = 0, vrl_ksv_cnt, vrl_sz;

        while (parsed_bytes < vrls_length) {
                vrl_ksv_cnt = *buf;
                ksv_count += vrl_ksv_cnt;

                vrl_sz = (vrl_ksv_cnt * DRM_HDCP_KSV_LEN) + 1;
                buf += vrl_sz;
                parsed_bytes += vrl_sz;
        }

        /*
         * When vrls are not valid, ksvs are not considered.
         * Hence SRM will be discarded.
         */
        if (parsed_bytes != vrls_length)
                ksv_count = 0;

        return ksv_count;
}

static u32 drm_hdcp_get_revoked_ksvs(const u8 *buf, u8 **revoked_ksv_list,
                                     u32 vrls_length)
{
        u32 vrl_ksv_cnt, vrl_ksv_sz, vrl_idx = 0;
        u32 parsed_bytes = 0, ksv_count = 0;

        do {
                vrl_ksv_cnt = *buf;
                vrl_ksv_sz = vrl_ksv_cnt * DRM_HDCP_KSV_LEN;

                buf++;

                DRM_DEBUG("vrl: %d, Revoked KSVs: %d\n", vrl_idx++,
                          vrl_ksv_cnt);
                memcpy((*revoked_ksv_list) + (ksv_count * DRM_HDCP_KSV_LEN),
                       buf, vrl_ksv_sz);

                ksv_count += vrl_ksv_cnt;
                buf += vrl_ksv_sz;

                parsed_bytes += (vrl_ksv_sz + 1);
        } while (parsed_bytes < vrls_length);

        return ksv_count;
}

static inline u32 get_vrl_length(const u8 *buf)
{
        return drm_hdcp_be24_to_cpu(buf);
}

static int drm_hdcp_parse_hdcp1_srm(const u8 *buf, size_t count,
                                    u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
{
        struct hdcp_srm_header *header;
        u32 vrl_length, ksv_count;

        if (count < (sizeof(struct hdcp_srm_header) +
            DRM_HDCP_1_4_VRL_LENGTH_SIZE + DRM_HDCP_1_4_DCP_SIG_SIZE)) {
                DRM_ERROR("Invalid blob length\n");
                return -EINVAL;
        }

        header = (struct hdcp_srm_header *)buf;
        DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
                  header->srm_id,
                  be16_to_cpu(header->srm_version), header->srm_gen_no);

        WARN_ON(header->reserved);

        buf = buf + sizeof(*header);
        vrl_length = get_vrl_length(buf);
        if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
            vrl_length < (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
                          DRM_HDCP_1_4_DCP_SIG_SIZE)) {
                DRM_ERROR("Invalid blob length or vrl length\n");
                return -EINVAL;
        }

        /* Length of the all vrls combined */
        vrl_length -= (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
                       DRM_HDCP_1_4_DCP_SIG_SIZE);

        if (!vrl_length) {
                DRM_ERROR("No vrl found\n");
                return -EINVAL;
        }

        buf += DRM_HDCP_1_4_VRL_LENGTH_SIZE;
        ksv_count = drm_hdcp_get_revoked_ksv_count(buf, vrl_length);
        if (!ksv_count) {
                DRM_DEBUG("Revoked KSV count is 0\n");
                return 0;
        }

        *revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, GFP_KERNEL);
        if (!*revoked_ksv_list) {
                DRM_ERROR("Out of Memory\n");
                return -ENOMEM;
        }

        if (drm_hdcp_get_revoked_ksvs(buf, revoked_ksv_list,
                                      vrl_length) != ksv_count) {
                *revoked_ksv_cnt = 0;
                kfree(*revoked_ksv_list);
                return -EINVAL;
        }

        *revoked_ksv_cnt = ksv_count;
        return 0;
}

static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count,
                                    u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
{
        struct hdcp_srm_header *header;
        u32 vrl_length, ksv_count, ksv_sz;

        if (count < (sizeof(struct hdcp_srm_header) +
            DRM_HDCP_2_VRL_LENGTH_SIZE + DRM_HDCP_2_DCP_SIG_SIZE)) {
                DRM_ERROR("Invalid blob length\n");
                return -EINVAL;
        }

        header = (struct hdcp_srm_header *)buf;
        DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
                  header->srm_id & DRM_HDCP_SRM_ID_MASK,
                  be16_to_cpu(header->srm_version), header->srm_gen_no);

        if (header->reserved)
                return -EINVAL;

        buf = buf + sizeof(*header);
        vrl_length = get_vrl_length(buf);

        if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
            vrl_length < (DRM_HDCP_2_VRL_LENGTH_SIZE +
            DRM_HDCP_2_DCP_SIG_SIZE)) {
                DRM_ERROR("Invalid blob length or vrl length\n");
                return -EINVAL;
        }

        /* Length of the all vrls combined */
        vrl_length -= (DRM_HDCP_2_VRL_LENGTH_SIZE +
                       DRM_HDCP_2_DCP_SIG_SIZE);

        if (!vrl_length) {
                DRM_ERROR("No vrl found\n");
                return -EINVAL;
        }

        buf += DRM_HDCP_2_VRL_LENGTH_SIZE;
        ksv_count = (*buf << 2) | DRM_HDCP_2_KSV_COUNT_2_LSBITS(*(buf + 1));
        if (!ksv_count) {
                DRM_DEBUG("Revoked KSV count is 0\n");
                return 0;
        }

        *revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, GFP_KERNEL);
        if (!*revoked_ksv_list) {
                DRM_ERROR("Out of Memory\n");
                return -ENOMEM;
        }

        ksv_sz = ksv_count * DRM_HDCP_KSV_LEN;
        buf += DRM_HDCP_2_NO_OF_DEV_PLUS_RESERVED_SZ;

        DRM_DEBUG("Revoked KSVs: %d\n", ksv_count);
        memcpy(*revoked_ksv_list, buf, ksv_sz);

        *revoked_ksv_cnt = ksv_count;
        return 0;
}

static inline bool is_srm_version_hdcp1(const u8 *buf)
{
        return *buf == (u8)(DRM_HDCP_1_4_SRM_ID << 4);
}

static inline bool is_srm_version_hdcp2(const u8 *buf)
{
        return *buf == (u8)(DRM_HDCP_2_SRM_ID << 4 | DRM_HDCP_2_INDICATOR);
}

static int drm_hdcp_srm_update(const u8 *buf, size_t count,
                               u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
{
        if (count < sizeof(struct hdcp_srm_header))
                return -EINVAL;

        if (is_srm_version_hdcp1(buf))
                return drm_hdcp_parse_hdcp1_srm(buf, count, revoked_ksv_list,
                                                revoked_ksv_cnt);
        else if (is_srm_version_hdcp2(buf))
                return drm_hdcp_parse_hdcp2_srm(buf, count, revoked_ksv_list,
                                                revoked_ksv_cnt);
        else
                return -EINVAL;
}

static int drm_hdcp_request_srm(struct drm_device *drm_dev,
                                u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
{
        char fw_name[36] = "display_hdcp_srm.bin";
        const struct firmware *fw;
        int ret;

        ret = request_firmware_direct(&fw, (const char *)fw_name,
                                      drm_dev->dev);
        if (ret < 0) {
                *revoked_ksv_cnt = 0;
                *revoked_ksv_list = NULL;
                ret = 0;
                goto exit;
        }

        if (fw->size && fw->data)
                ret = drm_hdcp_srm_update(fw->data, fw->size, revoked_ksv_list,
                                          revoked_ksv_cnt);

exit:
        release_firmware(fw);
        return ret;
}

/**
 * drm_hdcp_check_ksvs_revoked - Check the revoked status of the IDs
 *
 * @drm_dev: drm_device for which HDCP revocation check is requested
 * @ksvs: List of KSVs (HDCP receiver IDs)
 * @ksv_count: KSV count passed in through @ksvs
 *
 * This function reads the HDCP System renewability Message(SRM Table)
 * from userspace as a firmware and parses it for the revoked HDCP
 * KSVs(Receiver IDs) detected by DCP LLC. Once the revoked KSVs are known,
 * revoked state of the KSVs in the list passed in by display drivers are
 * decided and response is sent.
 *
 * SRM should be presented in the name of "display_hdcp_srm.bin".
 *
 * Format of the SRM table, that userspace needs to write into the binary file,
 * is defined at:
 * 1. Renewability chapter on 55th page of HDCP 1.4 specification
 * https://www.digital-cp.com/sites/default/files/specifications/HDCP%20Specification%20Rev1_4_Secure.pdf
 * 2. Renewability chapter on 63rd page of HDCP 2.2 specification
 * https://www.digital-cp.com/sites/default/files/specifications/HDCP%20on%20HDMI%20Specification%20Rev2_2_Final1.pdf
 *
 * Returns:
 * Count of the revoked KSVs or -ve error number in case of the failure.
 */
int drm_hdcp_check_ksvs_revoked(struct drm_device *drm_dev, u8 *ksvs,
                                u32 ksv_count)
{
        u32 revoked_ksv_cnt = 0, i, j;
        u8 *revoked_ksv_list = NULL;
        int ret = 0;

        ret = drm_hdcp_request_srm(drm_dev, &revoked_ksv_list,
                                   &revoked_ksv_cnt);
        if (ret)
                return ret;

        /* revoked_ksv_cnt will be zero when above function failed */
        for (i = 0; i < revoked_ksv_cnt; i++)
                for  (j = 0; j < ksv_count; j++)
                        if (!memcmp(&ksvs[j * DRM_HDCP_KSV_LEN],
                                    &revoked_ksv_list[i * DRM_HDCP_KSV_LEN],
                                    DRM_HDCP_KSV_LEN)) {
                                DRM_DEBUG("Revoked KSV is ");
                                drm_hdcp_print_ksv(&ksvs[j * DRM_HDCP_KSV_LEN]);
                                ret++;
                        }

        kfree(revoked_ksv_list);
        return ret;
}
EXPORT_SYMBOL_GPL(drm_hdcp_check_ksvs_revoked);

static struct drm_prop_enum_list drm_cp_enum_list[] = {
        { DRM_MODE_CONTENT_PROTECTION_UNDESIRED, "Undesired" },
        { DRM_MODE_CONTENT_PROTECTION_DESIRED, "Desired" },
        { DRM_MODE_CONTENT_PROTECTION_ENABLED, "Enabled" },
};
DRM_ENUM_NAME_FN(drm_get_content_protection_name, drm_cp_enum_list)

static struct drm_prop_enum_list drm_hdcp_content_type_enum_list[] = {
        { DRM_MODE_HDCP_CONTENT_TYPE0, "HDCP Type0" },
        { DRM_MODE_HDCP_CONTENT_TYPE1, "HDCP Type1" },
};
DRM_ENUM_NAME_FN(drm_get_hdcp_content_type_name,
                 drm_hdcp_content_type_enum_list)

/**
 * drm_connector_attach_content_protection_property - attach content protection
 * property
 *
 * @connector: connector to attach CP property on.
 * @hdcp_content_type: is HDCP Content Type property needed for connector
 *
 * This is used to add support for content protection on select connectors.
 * Content Protection is intentionally vague to allow for different underlying
 * technologies, however it is most implemented by HDCP.
 *
 * When hdcp_content_type is true enum property called HDCP Content Type is
 * created (if it is not already) and attached to the connector.
 *
 * This property is used for sending the protected content's stream type
 * from userspace to kernel on selected connectors. Protected content provider
 * will decide their type of their content and declare the same to kernel.
 *
 * Content type will be used during the HDCP 2.2 authentication.
 * Content type will be set to &drm_connector_state.hdcp_content_type.
 *
 * The content protection will be set to &drm_connector_state.content_protection
 *
 * When kernel triggered content protection state change like DESIRED->ENABLED
 * and ENABLED->DESIRED, will use drm_hdcp_update_content_protection() to update
 * the content protection state of a connector.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_connector_attach_content_protection_property(
                struct drm_connector *connector, bool hdcp_content_type)
{
        struct drm_device *dev = connector->dev;
        struct drm_property *prop =
                        dev->mode_config.content_protection_property;

        if (!prop)
                prop = drm_property_create_enum(dev, 0, "Content Protection",
                                                drm_cp_enum_list,
                                                ARRAY_SIZE(drm_cp_enum_list));
        if (!prop)
                return -ENOMEM;

        drm_object_attach_property(&connector->base, prop,
                                   DRM_MODE_CONTENT_PROTECTION_UNDESIRED);
        dev->mode_config.content_protection_property = prop;

        if (!hdcp_content_type)
                return 0;

        prop = dev->mode_config.hdcp_content_type_property;
        if (!prop)
                prop = drm_property_create_enum(dev, 0, "HDCP Content Type",
                                        drm_hdcp_content_type_enum_list,
                                        ARRAY_SIZE(
                                        drm_hdcp_content_type_enum_list));
        if (!prop)
                return -ENOMEM;

        drm_object_attach_property(&connector->base, prop,
                                   DRM_MODE_HDCP_CONTENT_TYPE0);
        dev->mode_config.hdcp_content_type_property = prop;

        return 0;
}
EXPORT_SYMBOL(drm_connector_attach_content_protection_property);

/**
 * drm_hdcp_update_content_protection - Updates the content protection state
 * of a connector
 *
 * @connector: drm_connector on which content protection state needs an update
 * @val: New state of the content protection property
 *
 * This function can be used by display drivers, to update the kernel triggered
 * content protection state changes of a drm_connector such as DESIRED->ENABLED
 * and ENABLED->DESIRED. No uevent for DESIRED->UNDESIRED or ENABLED->UNDESIRED,
 * as userspace is triggering such state change and kernel performs it without
 * fail.This function update the new state of the property into the connector's
 * state and generate an uevent to notify the userspace.
 */
void drm_hdcp_update_content_protection(struct drm_connector *connector,
                                        u64 val)
{
        struct drm_device *dev = connector->dev;
        struct drm_connector_state *state = connector->state;

        WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
        if (state->content_protection == val)
                return;

        state->content_protection = val;
        drm_sysfs_connector_property_event(connector,
                                           dev->mode_config.content_protection_property);
}
EXPORT_SYMBOL(drm_hdcp_update_content_protection);