// SPDX-License-Identifier: MIT
/*
 * Copyright 2023, Intel Corporation.
 */

#include <drm/drm_print.h>
#include <drm/intel/display_parent_interface.h>
#include <drm/intel/i915_hdcp_interface.h>

#include "gem/i915_gem_region.h"
#include "gt/intel_gt.h"
#include "gt/uc/intel_gsc_uc_heci_cmd_submit.h"
#include "i915_drv.h"
#include "i915_hdcp_gsc.h"

struct intel_hdcp_gsc_context {
        struct drm_i915_private *i915;
        struct i915_vma *vma;
        void *hdcp_cmd_in;
        void *hdcp_cmd_out;
};

static bool intel_hdcp_gsc_check_status(struct drm_device *drm)
{
        struct drm_i915_private *i915 = to_i915(drm);
        struct intel_gt *gt = i915->media_gt;
        struct intel_gsc_uc *gsc = gt ? &gt->uc.gsc : NULL;

        if (!gsc || !intel_uc_fw_is_running(&gsc->fw)) {
                drm_dbg_kms(&i915->drm,
                            "GSC components required for HDCP2.2 are not ready\n");
                return false;
        }

        return true;
}

/*This function helps allocate memory for the command that we will send to gsc cs */
static int intel_hdcp_gsc_initialize_message(struct drm_i915_private *i915,
                                             struct intel_hdcp_gsc_context *gsc_context)
{
        struct intel_gt *gt = i915->media_gt;
        struct drm_i915_gem_object *obj = NULL;
        struct i915_vma *vma = NULL;
        void *cmd_in, *cmd_out;
        int err;

        /* allocate object of two page for HDCP command memory and store it */
        obj = i915_gem_object_create_shmem(i915, 2 * PAGE_SIZE);

        if (IS_ERR(obj)) {
                drm_err(&i915->drm, "Failed to allocate HDCP streaming command!\n");
                return PTR_ERR(obj);
        }

        cmd_in = i915_gem_object_pin_map_unlocked(obj, intel_gt_coherent_map_type(gt, obj, true));
        if (IS_ERR(cmd_in)) {
                drm_err(&i915->drm, "Failed to map gsc message page!\n");
                err = PTR_ERR(cmd_in);
                goto out_unpin;
        }

        cmd_out = cmd_in + PAGE_SIZE;

        vma = i915_vma_instance(obj, &gt->ggtt->vm, NULL);
        if (IS_ERR(vma)) {
                err = PTR_ERR(vma);
                goto out_unmap;
        }

        err = i915_vma_pin(vma, 0, 0, PIN_GLOBAL | PIN_HIGH);
        if (err)
                goto out_unmap;

        memset(cmd_in, 0, obj->base.size);

        gsc_context->hdcp_cmd_in = cmd_in;
        gsc_context->hdcp_cmd_out = cmd_out;
        gsc_context->vma = vma;
        gsc_context->i915 = i915;

        return 0;

out_unmap:
        i915_gem_object_unpin_map(obj);
out_unpin:
        i915_gem_object_put(obj);
        return err;
}

static struct intel_hdcp_gsc_context *intel_hdcp_gsc_context_alloc(struct drm_device *drm)
{
        struct drm_i915_private *i915 = to_i915(drm);
        struct intel_hdcp_gsc_context *gsc_context;
        int ret;

        gsc_context = kzalloc_obj(*gsc_context);
        if (!gsc_context)
                return ERR_PTR(-ENOMEM);

        /*
         * NOTE: No need to lock the comp mutex here as it is already
         * going to be taken before this function called
         */
        ret = intel_hdcp_gsc_initialize_message(i915, gsc_context);
        if (ret) {
                drm_err(&i915->drm, "Could not initialize gsc_context\n");
                kfree(gsc_context);
                gsc_context = ERR_PTR(ret);
        }

        return gsc_context;
}

static void intel_hdcp_gsc_context_free(struct intel_hdcp_gsc_context *gsc_context)
{
        if (!gsc_context)
                return;

        i915_vma_unpin_and_release(&gsc_context->vma, I915_VMA_RELEASE_MAP);
        kfree(gsc_context);
}

static int intel_gsc_send_sync(struct drm_i915_private *i915,
                               struct intel_gsc_mtl_header *header_in,
                               struct intel_gsc_mtl_header *header_out,
                               u64 addr_in, u64 addr_out,
                               size_t msg_out_len)
{
        struct intel_gt *gt = i915->media_gt;
        int ret;

        ret = intel_gsc_uc_heci_cmd_submit_packet(&gt->uc.gsc, addr_in,
                                                  header_in->message_size,
                                                  addr_out,
                                                  msg_out_len + sizeof(*header_out));
        if (ret) {
                drm_err(&i915->drm, "failed to send gsc HDCP msg (%d)\n", ret);
                return ret;
        }

        /*
         * Checking validity marker and header status to see if some error has
         * blocked us from sending message to gsc cs
         */
        if (header_out->validity_marker != GSC_HECI_VALIDITY_MARKER) {
                drm_err(&i915->drm, "invalid validity marker\n");
                return -EINVAL;
        }

        if (header_out->status != 0) {
                drm_err(&i915->drm, "header status indicates error %d\n",
                        header_out->status);
                return -EINVAL;
        }

        if (header_out->flags & GSC_OUTFLAG_MSG_PENDING) {
                header_in->gsc_message_handle = header_out->gsc_message_handle;
                return -EAGAIN;
        }

        return 0;
}

/*
 * This function can now be used for sending requests and will also handle
 * receipt of reply messages hence no different function of message retrieval
 * is required. We will initialize intel_hdcp_gsc_context structure then add
 * gsc cs memory header as stated in specs after which the normal HDCP payload
 * will follow
 */
static ssize_t intel_hdcp_gsc_msg_send(struct intel_hdcp_gsc_context *gsc_context,
                                       void *msg_in, size_t msg_in_len,
                                       void *msg_out, size_t msg_out_len)
{
        struct drm_i915_private *i915 = gsc_context->i915;
        struct intel_gt *gt = i915->media_gt;
        struct intel_gsc_mtl_header *header_in, *header_out;
        const size_t max_msg_size = PAGE_SIZE - sizeof(*header_in);
        u64 addr_in, addr_out, host_session_id;
        u32 reply_size, msg_size_in, msg_size_out;
        int ret, tries = 0;

        if (!intel_uc_uses_gsc_uc(&gt->uc))
                return -ENODEV;

        if (msg_in_len > max_msg_size || msg_out_len > max_msg_size)
                return -ENOSPC;

        msg_size_in = msg_in_len + sizeof(*header_in);
        msg_size_out = msg_out_len + sizeof(*header_out);
        header_in = gsc_context->hdcp_cmd_in;
        header_out = gsc_context->hdcp_cmd_out;
        addr_in = i915_ggtt_offset(gsc_context->vma);
        addr_out = addr_in + PAGE_SIZE;

        memset(header_in, 0, msg_size_in);
        memset(header_out, 0, msg_size_out);
        get_random_bytes(&host_session_id, sizeof(u64));
        intel_gsc_uc_heci_cmd_emit_mtl_header(header_in, HECI_MEADDRESS_HDCP,
                                              msg_size_in, host_session_id);
        memcpy(gsc_context->hdcp_cmd_in + sizeof(*header_in), msg_in, msg_in_len);

        /*
         * Keep sending request in case the pending bit is set no need to add
         * message handle as we are using same address hence loc. of header is
         * same and it will contain the message handle. we will send the message
         * 20 times each message 50 ms apart
         */
        do {
                ret = intel_gsc_send_sync(i915, header_in, header_out, addr_in,
                                          addr_out, msg_out_len);

                /* Only try again if gsc says so */
                if (ret != -EAGAIN)
                        break;

                msleep(50);

        } while (++tries < 20);

        if (ret)
                goto err;

        /* we use the same mem for the reply, so header is in the same loc */
        reply_size = header_out->message_size - sizeof(*header_out);
        if (reply_size > msg_out_len) {
                drm_warn(&i915->drm, "caller with insufficient HDCP reply size %u (%d)\n",
                         reply_size, (u32)msg_out_len);
                reply_size = msg_out_len;
        } else if (reply_size != msg_out_len) {
                drm_dbg_kms(&i915->drm, "caller unexpected HCDP reply size %u (%d)\n",
                            reply_size, (u32)msg_out_len);
        }

        memcpy(msg_out, gsc_context->hdcp_cmd_out + sizeof(*header_out), msg_out_len);

err:
        return ret;
}

const struct intel_display_hdcp_interface i915_display_hdcp_interface = {
        .gsc_msg_send = intel_hdcp_gsc_msg_send,
        .gsc_check_status = intel_hdcp_gsc_check_status,
        .gsc_context_alloc = intel_hdcp_gsc_context_alloc,
        .gsc_context_free = intel_hdcp_gsc_context_free,
};