/*
 * SPDX-FileCopyrightText: 2020 Efabless Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * SPDX-License-Identifier: Apache-2.0
 */

// This include is relative to $CARAVEL_PATH (see Makefile)
#include <defs.h>
#include <stub.c>

#define GPIO0_OE_WRITE_ADDR ((uint32_t*)0x33031000)
#define GPIO0_OE_SET_ADDR ((uint32_t*)0x33031004)
#define GPIO0_OE_CLEAR_ADDR ((uint32_t*)0x33031008)
#define GPIO0_OE_TOGGLE_ADDR ((uint32_t*)0x3303100C)
#define GPIO0_OUTPUT_WRITE_ADDR ((uint32_t*)0x33031010)
#define GPIO0_OUTPUT_SET_ADDR ((uint32_t*)0x33031014)
#define GPIO0_OUTPUT_CLEAR_ADDR ((uint32_t*)0x33031018)
#define GPIO0_OUTPUT_TOGGLE_ADDR ((uint32_t*)0x3303101C)
#define GPIO0_INPUT_ADDR ((uint32_t*)0x33031020)
#define GPIO1_OE_WRITE_ADDR ((uint32_t*)0x33032000)
#define GPIO1_OE_SET_ADDR ((uint32_t*)0x33032004)
#define GPIO1_OE_CLEAR_ADDR ((uint32_t*)0x33032008)
#define GPIO1_OE_TOGGLE_ADDR ((uint32_t*)0x3303200C)
#define GPIO1_OUTPUT_WRITE_ADDR ((uint32_t*)0x33032010)
#define GPIO1_OUTPUT_SET_ADDR ((uint32_t*)0x33032014)
#define GPIO1_OUTPUT_CLEAR_ADDR ((uint32_t*)0x33032018)
#define GPIO1_OUTPUT_TOGGLE_ADDR ((uint32_t*)0x3303201C)
#define GPIO1_INPUT_ADDR ((uint32_t*)0x33032020)

#define SPI0_CONFIGURATION_REGISTER ((uint32_t*)0x33011000)
#define SPI0_STATUS_REGISTER ((uint32_t*)0x33011004)
#define SPI0_DATA ((uint32_t*)0x33011008)

#define MPRJ_WB_ADDRESS (*(volatile uint32_t*)0x30000000)
#define MPRJ_WB_DATA_LOCATION 0x30008000

void wbWrite (uint32_t* location, uint32_t value)
{
	// Write the address
	uint32_t locationData = (uint32_t)location;
	MPRJ_WB_ADDRESS = locationData & 0xFFFF8000;

	// Write the data
	uint32_t writeAddress = (locationData & 0x00007FFF) | MPRJ_WB_DATA_LOCATION;
	*((volatile uint32_t*)writeAddress) = value;
}

uint32_t wbRead (uint32_t* location)
{
	// Write the address
	uint32_t locationData = (uint32_t)location;
	MPRJ_WB_ADDRESS = locationData & 0xFFFF8000;

	// Write the data
	uint32_t writeAddress = (locationData & 0x00007FFF) | MPRJ_WB_DATA_LOCATION;
	return *((volatile uint32_t*)writeAddress);
}

void nextTest (bool testPassing)
{
	if (testPassing)
	{
		wbWrite (GPIO0_OUTPUT_SET_ADDR, 0x03000);
	}
	else
	{
		wbWrite (GPIO0_OUTPUT_CLEAR_ADDR, 0x01000);
		wbWrite (GPIO0_OUTPUT_SET_ADDR, 0x02000);
	}

	wbWrite (GPIO0_OUTPUT_CLEAR_ADDR, 0x02000);
}

void main ()
{
	/*
	IO Control Registers
	| DM     | VTRIP | SLOW  | AN_POL | AN_SEL | AN_EN | MOD_SEL | INP_DIS | HOLDH | OEB_N | MGMT_EN |
	| 3-bits | 1-bit | 1-bit | 1-bit  | 1-bit  | 1-bit | 1-bit   | 1-bit   | 1-bit | 1-bit | 1-bit   |

	Output: 0000_0110_0000_1110  (0x1808) = GPIO_MODE_USER_STD_OUTPUT
	| DM     | VTRIP | SLOW  | AN_POL | AN_SEL | AN_EN | MOD_SEL | INP_DIS | HOLDH | OEB_N | MGMT_EN |
	| 110    | 0     | 0     | 0      | 0      | 0     | 0       | 1       | 0     | 0     | 0       |


	Input: 0000_0001_0000_1111 (0x0402) = GPIO_MODE_USER_STD_INPUT_NOPULL
	| DM     | VTRIP | SLOW  | AN_POL | AN_SEL | AN_EN | MOD_SEL | INP_DIS | HOLDH | OEB_N | MGMT_EN |
	| 001    | 0     | 0     | 0      | 0      | 0     | 0       | 0       | 0     | 1     | 0       |

	*/

	/* Set up the housekeeping SPI to be connected internally so	*/
	/* that external pin changes don't affect it.			*/

	// Connect the housekeeping SPI to the SPI master
	// so that the CSB line is not left floating.  This allows
	// all of the GPIO pins to be used for user functions.

	// https://github.com/efabless/caravel/blob/main/docs/other/gpio.txt

	// Enable the wishbone bus
	reg_wb_enable = 1;

	// Enable GPIO
	reg_mprj_io_12 = GPIO_MODE_USER_STD_OUTPUT;
	reg_mprj_io_13 = GPIO_MODE_USER_STD_OUTPUT;
	reg_mprj_io_22 = GPIO_MODE_USER_STD_OUTPUT;
	reg_mprj_io_23 = GPIO_MODE_USER_STD_OUTPUT;
	reg_mprj_io_24 = GPIO_MODE_USER_STD_INPUT_NOPULL;
	reg_mprj_io_25 = GPIO_MODE_USER_STD_OUTPUT;

	/* Apply configuration */
	reg_mprj_xfer = 1;
	while (reg_mprj_xfer == 1) {}

	// Setup test output
	bool testPass = true;
	wbWrite (GPIO0_OUTPUT_WRITE_ADDR, 0x01000);
	wbWrite (GPIO0_OE_WRITE_ADDR, ~0x03000);

	// Write clock high and low to test target is correctly using chip select
	// Set chip select high first for its default value
	wbWrite (GPIO1_OE_WRITE_ADDR, ~0x48);
	wbWrite (GPIO1_OUTPUT_SET_ADDR, 0x40);
	wbWrite (GPIO1_OUTPUT_SET_ADDR, 0x08);
	wbWrite (GPIO1_OUTPUT_CLEAR_ADDR, 0x08);

	// Check device 0 config
	// b00-b02: clockScale 		Default 0x4
	// b03-04: spiMode 			Default 0x0
	// b05: msbFirst 			Default 0x1
	// b06: useCS 				Default 0x1
	// b07: activeHighCS		Default 0x0
	// b08: enable				Default 0x0
	uint32_t device0Config = (0b1 << 8) | (0b11 << 5) | 0x04;
	wbWrite (SPI0_CONFIGURATION_REGISTER, device0Config);
	if (wbRead (SPI0_CONFIGURATION_REGISTER) != device0Config) testPass = false;
	nextTest (testPass);

	// Write fist test byte
	wbWrite (SPI0_DATA, 0x1F);

	// Check device isn't busy
	if (wbRead (SPI0_STATUS_REGISTER) != 0) testPass = false;
	nextTest (testPass);

	// Check that data was received
	if (wbRead (SPI0_DATA) != 0xC5) testPass = false;
	nextTest (testPass);

	// Write second test byte
	wbWrite (SPI0_DATA, 0xA3);

	// Check data received back is correct
	// This should be the first test byte
	if (wbRead (SPI0_DATA) != 0x1F) testPass = false;
	nextTest (testPass);

	// Change to active low clock mode
	device0Config = (0b1 << 8) | (0b11 << 5) | (0b11 << 3) | 0x04;
	wbWrite (SPI0_CONFIGURATION_REGISTER, device0Config);
	if (wbRead (SPI0_CONFIGURATION_REGISTER) != device0Config) testPass = false;
	nextTest (testPass);

	// Write fist test byte
	wbWrite (SPI0_DATA, 0x1F);

	// Check data data was received
	if (wbRead (SPI0_DATA) != 0xA3) testPass = false;
	nextTest (testPass);

	// Write second test byte
	wbWrite (SPI0_DATA, 0x83);

	// Check data received back is correct
	// This should be the first test byte
	if (wbRead (SPI0_DATA) != 0x1F) testPass = false;
	nextTest (testPass);

	device0Config = (0b1 << 8) | (0b11 << 5) | 0x04;
	wbWrite (SPI0_CONFIGURATION_REGISTER, device0Config);
	if (wbRead (SPI0_CONFIGURATION_REGISTER) != device0Config) testPass = false;
	nextTest (testPass);

	// Write third test byte for timing test
	wbWrite (SPI0_DATA, 0x9B);

	// Finish test
	nextTest (testPass);
}