/*
 *  yosys -- Yosys Open SYnthesis Suite
 *
 *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
 *
 *  Permission to use, copy, modify, and/or distribute this software for any
 *  purpose with or without fee is hereby granted, provided that the above
 *  copyright notice and this permission notice appear in all copies.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#include "kernel/yosys.h"
#include "kernel/sigtools.h"

USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN

bool memcells_cmp(Cell *a, Cell *b)
{
	if (a->type == "$memrd" && b->type == "$memrd")
		return a->name < b->name;
	if (a->type == "$memrd" || b->type == "$memrd")
		return (a->type == "$memrd") < (b->type == "$memrd");
	return a->parameters.at("\\PRIORITY").as_int() < b->parameters.at("\\PRIORITY").as_int();
}

Cell *handle_memory(Module *module, RTLIL::Memory *memory)
{
	log("Collecting $memrd, $memwr and $meminit for memory `%s' in module `%s':\n",
			memory->name.c_str(), module->name.c_str());

	Const init_data(State::Sx, memory->size * memory->width);
	SigMap sigmap(module);

	int wr_ports = 0;
	SigSpec sig_wr_clk;
	SigSpec sig_wr_clk_enable;
	SigSpec sig_wr_clk_polarity;
	SigSpec sig_wr_addr;
	SigSpec sig_wr_data;
	SigSpec sig_wr_en;

	int rd_ports = 0;
	SigSpec sig_rd_clk;
	SigSpec sig_rd_clk_enable;
	SigSpec sig_rd_clk_polarity;
	SigSpec sig_rd_transparent;
	SigSpec sig_rd_addr;
	SigSpec sig_rd_data;
	SigSpec sig_rd_en;

	int addr_bits = 0;
	std::vector<Cell*> memcells;

	for (auto &cell_it : module->cells_) {
		Cell *cell = cell_it.second;
		if (cell->type.in("$memrd", "$memwr", "$meminit") && memory->name == cell->parameters["\\MEMID"].decode_string()) {
			SigSpec addr = sigmap(cell->getPort("\\ADDR"));
			for (int i = 0; i < GetSize(addr); i++)
				if (addr[i] != State::S0)
					addr_bits = std::max(addr_bits, i+1);
			memcells.push_back(cell);
		}
	}

	if (memory->start_offset == 0 && addr_bits < 30 && (1 << addr_bits) < memory->size)
		memory->size = 1 << addr_bits;

	if (memory->start_offset >= 0)
		addr_bits = std::min(addr_bits, ceil_log2(memory->size + memory->start_offset));

	addr_bits = std::max(addr_bits, 1);

	if (memcells.empty()) {
		log("  no cells found. removing memory.\n");
		return nullptr;
	}

	std::sort(memcells.begin(), memcells.end(), memcells_cmp);

	for (auto cell : memcells)
	{
		log("  %s (%s)\n", log_id(cell), log_id(cell->type));

		if (cell->type == "$meminit")
		{
			SigSpec addr = sigmap(cell->getPort("\\ADDR"));
			SigSpec data = sigmap(cell->getPort("\\DATA"));

			if (!addr.is_fully_const())
				log_error("Non-constant address %s in memory initialization %s.\n", log_signal(addr), log_id(cell));
			if (!data.is_fully_const())
				log_error("Non-constant data %s in memory initialization %s.\n", log_signal(data), log_id(cell));

			int offset = (addr.as_int() - memory->start_offset) * memory->width;

			if (offset < 0 || offset + GetSize(data) > GetSize(init_data))
				log_warning("Address %s in memory initialization %s is out-of-bounds.\n", log_signal(addr), log_id(cell));

			for (int i = 0; i < GetSize(data); i++)
				if (0 <= i+offset && i+offset < GetSize(init_data))
					init_data.bits[i+offset] = data[i].data;

			continue;
		}

		if (cell->type == "$memwr")
		{
			SigSpec clk = sigmap(cell->getPort("\\CLK"));
			SigSpec clk_enable = SigSpec(cell->parameters["\\CLK_ENABLE"]);
			SigSpec clk_polarity = SigSpec(cell->parameters["\\CLK_POLARITY"]);
			SigSpec addr = sigmap(cell->getPort("\\ADDR"));
			SigSpec data = sigmap(cell->getPort("\\DATA"));
			SigSpec en = sigmap(cell->getPort("\\EN"));

			if (!en.is_fully_zero())
			{
				clk.extend_u0(1, false);
				clk_enable.extend_u0(1, false);
				clk_polarity.extend_u0(1, false);
				addr.extend_u0(addr_bits, false);
				data.extend_u0(memory->width, false);
				en.extend_u0(memory->width, false);

				sig_wr_clk.append(clk);
				sig_wr_clk_enable.append(clk_enable);
				sig_wr_clk_polarity.append(clk_polarity);
				sig_wr_addr.append(addr);
				sig_wr_data.append(data);
				sig_wr_en.append(en);

				wr_ports++;
			}
			continue;
		}

		if (cell->type == "$memrd")
		{
			SigSpec clk = sigmap(cell->getPort("\\CLK"));
			SigSpec clk_enable = SigSpec(cell->parameters["\\CLK_ENABLE"]);
			SigSpec clk_polarity = SigSpec(cell->parameters["\\CLK_POLARITY"]);
			SigSpec transparent = SigSpec(cell->parameters["\\TRANSPARENT"]);
			SigSpec addr = sigmap(cell->getPort("\\ADDR"));
			SigSpec data = sigmap(cell->getPort("\\DATA"));
			SigSpec en = sigmap(cell->getPort("\\EN"));

			if (!en.is_fully_zero())
			{
				clk.extend_u0(1, false);
				clk_enable.extend_u0(1, false);
				clk_polarity.extend_u0(1, false);
				transparent.extend_u0(1, false);
				addr.extend_u0(addr_bits, false);
				data.extend_u0(memory->width, false);

				sig_rd_clk.append(clk);
				sig_rd_clk_enable.append(clk_enable);
				sig_rd_clk_polarity.append(clk_polarity);
				sig_rd_transparent.append(transparent);
				sig_rd_addr.append(addr);
				sig_rd_data.append(data);
				sig_rd_en.append(en);

				rd_ports++;
			}
			continue;
		}
	}

	std::stringstream sstr;
	sstr << "$mem$" << memory->name.str() << "$" << (autoidx++);

	Cell *mem = module->addCell(sstr.str(), "$mem");
	mem->parameters["\\MEMID"] = Const(memory->name.str());
	mem->parameters["\\WIDTH"] = Const(memory->width);
	mem->parameters["\\OFFSET"] = Const(memory->start_offset);
	mem->parameters["\\SIZE"] = Const(memory->size);
	mem->parameters["\\ABITS"] = Const(addr_bits);

	while (GetSize(init_data) > 1 && init_data.bits.back() == State::Sx && init_data.bits[GetSize(init_data)-2] == State::Sx)
		init_data.bits.pop_back();
	mem->parameters["\\INIT"] = init_data;

	log_assert(sig_wr_clk.size() == wr_ports);
	log_assert(sig_wr_clk_enable.size() == wr_ports && sig_wr_clk_enable.is_fully_const());
	log_assert(sig_wr_clk_polarity.size() == wr_ports && sig_wr_clk_polarity.is_fully_const());
	log_assert(sig_wr_addr.size() == wr_ports * addr_bits);
	log_assert(sig_wr_data.size() == wr_ports * memory->width);
	log_assert(sig_wr_en.size() == wr_ports * memory->width);

	mem->parameters["\\WR_PORTS"] = Const(wr_ports);
	mem->parameters["\\WR_CLK_ENABLE"] = wr_ports ? sig_wr_clk_enable.as_const() : Const(0, 1);
	mem->parameters["\\WR_CLK_POLARITY"] = wr_ports ? sig_wr_clk_polarity.as_const() : Const(0, 1);

	mem->setPort("\\WR_CLK", sig_wr_clk);
	mem->setPort("\\WR_ADDR", sig_wr_addr);
	mem->setPort("\\WR_DATA", sig_wr_data);
	mem->setPort("\\WR_EN", sig_wr_en);

	log_assert(sig_rd_clk.size() == rd_ports);
	log_assert(sig_rd_clk_enable.size() == rd_ports && sig_rd_clk_enable.is_fully_const());
	log_assert(sig_rd_clk_polarity.size() == rd_ports && sig_rd_clk_polarity.is_fully_const());
	log_assert(sig_rd_addr.size() == rd_ports * addr_bits);
	log_assert(sig_rd_data.size() == rd_ports * memory->width);

	mem->parameters["\\RD_PORTS"] = Const(rd_ports);
	mem->parameters["\\RD_CLK_ENABLE"] = rd_ports ? sig_rd_clk_enable.as_const() : Const(0, 1);
	mem->parameters["\\RD_CLK_POLARITY"] = rd_ports ? sig_rd_clk_polarity.as_const() : Const(0, 1);
	mem->parameters["\\RD_TRANSPARENT"] = rd_ports ? sig_rd_transparent.as_const() : Const(0, 1);

	mem->setPort("\\RD_CLK", sig_rd_clk);
	mem->setPort("\\RD_ADDR", sig_rd_addr);
	mem->setPort("\\RD_DATA", sig_rd_data);
	mem->setPort("\\RD_EN", sig_rd_en);

	for (auto c : memcells)
		module->remove(c);

	return mem;
}

static void handle_module(Design *design, Module *module)
{
	std::vector<pair<Cell*, IdString>> finqueue;

	for (auto &mem_it : module->memories)
		if (design->selected(module, mem_it.second)) {
			Cell *c = handle_memory(module, mem_it.second);
			finqueue.push_back(pair<Cell*, IdString>(c, mem_it.first));
		}
	for (auto &it : finqueue) {
		delete module->memories.at(it.second);
		module->memories.erase(it.second);
		if (it.first)
			module->rename(it.first, it.second);
	}
}

struct MemoryCollectPass : public Pass {
	MemoryCollectPass() : Pass("memory_collect", "creating multi-port memory cells") { }
	void help() YS_OVERRIDE
	{
		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
		log("\n");
		log("    memory_collect [selection]\n");
		log("\n");
		log("This pass collects memories and memory ports and creates generic multiport\n");
		log("memory cells.\n");
		log("\n");
	}
	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE {
		log_header(design, "Executing MEMORY_COLLECT pass (generating $mem cells).\n");
		extra_args(args, 1, design);
		for (auto &mod_it : design->modules_)
			if (design->selected(mod_it.second))
				handle_module(design, mod_it.second);
	}
} MemoryCollectPass;

PRIVATE_NAMESPACE_END