// SPDX-License-Identifier: GPL-2.0+
/* Copyright (C) 2023 AVM GmbH <fritzbox_info@avm.de> */

#define pr_fmt(fmt) "mrpc dtbo server: " fmt

#include <linux/mrpc.h>
#include <linux/module.h>
#include <asm/byteorder.h>
#include <linux/memblock.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <avm/sammel/avm_of_overlay_cmdline.h>

#include "avm_dtbo_mrpc.h"

static struct mrpc_server *server;

#define MAX_DT_OVERLAYS CONFIG_AVM_OF_OVERLAY_CMDLINE_MAX
static const struct dt_overlay_mem *dtbo_array[MAX_DT_OVERLAYS];
static size_t num_dtbo;

static void mprc_avm_dtbo_fill_array(void)
{
	for (num_dtbo = 0; num_dtbo < MAX_DT_OVERLAYS; num_dtbo++) {

		dtbo_array[num_dtbo] = avm_of_overlay_get_dtbo_mem(num_dtbo);
		if (dtbo_array[num_dtbo] == NULL)
			break;
	}
}

static int mrpc_avm_dtbo_server_read(void *arg, ssize_t arglen,
				     void *rep, ssize_t replen)
{
	struct avm_dtbo_read_request *request = arg;
	struct avm_dtbo_read_reply *reply = rep;
	const struct dt_overlay_mem *dtbo;
	u32 offset, len, dtbo_index;

	offset = be32_to_cpu(request->offset);
	len = be32_to_cpu(request->len);
	dtbo_index = be32_to_cpu(request->dtbo_index);

	if (dtbo_index >= num_dtbo) {
		reply->data_len = 0;
		return 0;
	}

	dtbo = dtbo_array[dtbo_index];
	if ((offset + len) > dtbo->size)
		len = dtbo->size - offset;

	memcpy(reply->data, dtbo->dtbo + offset, len);
	reply->data_len = cpu_to_be32(len);
	reply->dtbo_size = cpu_to_be32(dtbo->size);

	return 0;
}


static struct mrpc_procinfo avm_dtbo_server_procs[] = {
	/* Request enum, Handle function, Argument length, Reply length */
	MRPC_PROCINFO_ENTRY(MRPC_AVM_DTBO_READ,
			 mrpc_avm_dtbo_server_read,
			 sizeof(struct avm_dtbo_read_request),
			 sizeof(struct avm_dtbo_read_reply)),

};

static int __init avm_dtbo_server_init(void)
{
	mprc_avm_dtbo_fill_array();

	server = mrpc_server_register(
		MRPC_RESERVED_ID_AVM_DTBO,
		"AVM dtbo server",
		avm_dtbo_server_procs,
		ARRAY_SIZE(avm_dtbo_server_procs));

	if (!server)
		return -ENODEV;

	return 0;
}
module_init(avm_dtbo_server_init);