1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2012 Stefan Roese <sr@denx.de>
4  */
5 
6 #include <linux/device.h>
7 #include <linux/firmware.h>
8 #include <linux/module.h>
9 #include <linux/errno.h>
10 #include <linux/kernel.h>
11 #include <linux/spi/spi.h>
12 #include <linux/platform_device.h>
13 #include <linux/delay.h>
14 #include <asm/unaligned.h>
15 
16 #define FIRMWARE_NAME	"lattice-ecp3.bit"
17 
18 /*
19  * The JTAG ID's of the supported FPGA's. The ID is 32bit wide
20  * reversed as noted in the manual.
21  */
22 #define ID_ECP3_17	0xc2088080
23 #define ID_ECP3_35	0xc2048080
24 
25 /* FPGA commands */
26 #define FPGA_CMD_READ_ID	0x07	/* plus 24 bits */
27 #define FPGA_CMD_READ_STATUS	0x09	/* plus 24 bits */
28 #define FPGA_CMD_CLEAR		0x70
29 #define FPGA_CMD_REFRESH	0x71
30 #define FPGA_CMD_WRITE_EN	0x4a	/* plus 2 bits */
31 #define FPGA_CMD_WRITE_DIS	0x4f	/* plus 8 bits */
32 #define FPGA_CMD_WRITE_INC	0x41	/* plus 0 bits */
33 
34 /*
35  * The status register is 32bit revered, DONE is bit 17 from the TN1222.pdf
36  * (LatticeECP3 Slave SPI Port User's Guide)
37  */
38 #define FPGA_STATUS_DONE	0x00004000
39 #define FPGA_STATUS_CLEARED	0x00010000
40 
41 #define FPGA_CLEAR_TIMEOUT	5000	/* max. 5000ms for FPGA clear */
42 #define FPGA_CLEAR_MSLEEP	10
43 #define FPGA_CLEAR_LOOP_COUNT	(FPGA_CLEAR_TIMEOUT / FPGA_CLEAR_MSLEEP)
44 
45 struct fpga_data {
46 	struct completion fw_loaded;
47 };
48 
49 struct ecp3_dev {
50 	u32 jedec_id;
51 	char *name;
52 };
53 
54 static const struct ecp3_dev ecp3_dev[] = {
55 	{
56 		.jedec_id = ID_ECP3_17,
57 		.name = "Lattice ECP3-17",
58 	},
59 	{
60 		.jedec_id = ID_ECP3_35,
61 		.name = "Lattice ECP3-35",
62 	},
63 };
64 
65 static void firmware_load(const struct firmware *fw, void *context)
66 {
67 	struct spi_device *spi = (struct spi_device *)context;
68 	struct fpga_data *data = spi_get_drvdata(spi);
69 	u8 *buffer;
70 	u8 txbuf[8];
71 	u8 rxbuf[8];
72 	int rx_len = 8;
73 	int i;
74 	u32 jedec_id;
75 	u32 status;
76 
77 	if (fw == NULL) {
78 		dev_err(&spi->dev, "Cannot load firmware, aborting\n");
79 		goto out;
80 	}
81 
82 	if (fw->size == 0) {
83 		dev_err(&spi->dev, "Error: Firmware size is 0!\n");
84 		goto out;
85 	}
86 
87 	/* Fill dummy data (24 stuffing bits for commands) */
88 	txbuf[1] = 0x00;
89 	txbuf[2] = 0x00;
90 	txbuf[3] = 0x00;
91 
92 	/* Trying to speak with the FPGA via SPI... */
93 	txbuf[0] = FPGA_CMD_READ_ID;
94 	spi_write_then_read(spi, txbuf, 8, rxbuf, rx_len);
95 	jedec_id = get_unaligned_be32(&rxbuf[4]);
96 	dev_dbg(&spi->dev, "FPGA JTAG ID=%08x\n", jedec_id);
97 
98 	for (i = 0; i < ARRAY_SIZE(ecp3_dev); i++) {
99 		if (jedec_id == ecp3_dev[i].jedec_id)
100 			break;
101 	}
102 	if (i == ARRAY_SIZE(ecp3_dev)) {
103 		dev_err(&spi->dev,
104 			"Error: No supported FPGA detected (JEDEC_ID=%08x)!\n",
105 			jedec_id);
106 		goto out;
107 	}
108 
109 	dev_info(&spi->dev, "FPGA %s detected\n", ecp3_dev[i].name);
110 
111 	txbuf[0] = FPGA_CMD_READ_STATUS;
112 	spi_write_then_read(spi, txbuf, 8, rxbuf, rx_len);
113 	status = get_unaligned_be32(&rxbuf[4]);
114 	dev_dbg(&spi->dev, "FPGA Status=%08x\n", status);
115 
116 	buffer = kzalloc(fw->size + 8, GFP_KERNEL);
117 	if (!buffer) {
118 		dev_err(&spi->dev, "Error: Can't allocate memory!\n");
119 		goto out;
120 	}
121 
122 	/*
123 	 * Insert WRITE_INC command into stream (one SPI frame)
124 	 */
125 	buffer[0] = FPGA_CMD_WRITE_INC;
126 	buffer[1] = 0xff;
127 	buffer[2] = 0xff;
128 	buffer[3] = 0xff;
129 	memcpy(buffer + 4, fw->data, fw->size);
130 
131 	txbuf[0] = FPGA_CMD_REFRESH;
132 	spi_write(spi, txbuf, 4);
133 
134 	txbuf[0] = FPGA_CMD_WRITE_EN;
135 	spi_write(spi, txbuf, 4);
136 
137 	txbuf[0] = FPGA_CMD_CLEAR;
138 	spi_write(spi, txbuf, 4);
139 
140 	/*
141 	 * Wait for FPGA memory to become cleared
142 	 */
143 	for (i = 0; i < FPGA_CLEAR_LOOP_COUNT; i++) {
144 		txbuf[0] = FPGA_CMD_READ_STATUS;
145 		spi_write_then_read(spi, txbuf, 8, rxbuf, rx_len);
146 		status = get_unaligned_be32(&rxbuf[4]);
147 		if (status == FPGA_STATUS_CLEARED)
148 			break;
149 
150 		msleep(FPGA_CLEAR_MSLEEP);
151 	}
152 
153 	if (i == FPGA_CLEAR_LOOP_COUNT) {
154 		dev_err(&spi->dev,
155 			"Error: Timeout waiting for FPGA to clear (status=%08x)!\n",
156 			status);
157 		kfree(buffer);
158 		goto out;
159 	}
160 
161 	dev_info(&spi->dev, "Configuring the FPGA...\n");
162 	spi_write(spi, buffer, fw->size + 8);
163 
164 	txbuf[0] = FPGA_CMD_WRITE_DIS;
165 	spi_write(spi, txbuf, 4);
166 
167 	txbuf[0] = FPGA_CMD_READ_STATUS;
168 	spi_write_then_read(spi, txbuf, 8, rxbuf, rx_len);
169 	status = get_unaligned_be32(&rxbuf[4]);
170 	dev_dbg(&spi->dev, "FPGA Status=%08x\n", status);
171 
172 	/* Check result */
173 	if (status & FPGA_STATUS_DONE)
174 		dev_info(&spi->dev, "FPGA successfully configured!\n");
175 	else
176 		dev_info(&spi->dev, "FPGA not configured (DONE not set)\n");
177 
178 	/*
179 	 * Don't forget to release the firmware again
180 	 */
181 	release_firmware(fw);
182 
183 	kfree(buffer);
184 out:
185 	complete(&data->fw_loaded);
186 }
187 
188 static int lattice_ecp3_probe(struct spi_device *spi)
189 {
190 	struct fpga_data *data;
191 	int err;
192 
193 	data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
194 	if (!data) {
195 		dev_err(&spi->dev, "Memory allocation for fpga_data failed\n");
196 		return -ENOMEM;
197 	}
198 	spi_set_drvdata(spi, data);
199 
200 	init_completion(&data->fw_loaded);
201 	err = request_firmware_nowait(THIS_MODULE, FW_ACTION_UEVENT,
202 				      FIRMWARE_NAME, &spi->dev,
203 				      GFP_KERNEL, spi, firmware_load);
204 	if (err) {
205 		dev_err(&spi->dev, "Firmware loading failed with %d!\n", err);
206 		return err;
207 	}
208 
209 	dev_info(&spi->dev, "FPGA bitstream configuration driver registered\n");
210 
211 	return 0;
212 }
213 
214 static int lattice_ecp3_remove(struct spi_device *spi)
215 {
216 	struct fpga_data *data = spi_get_drvdata(spi);
217 
218 	wait_for_completion(&data->fw_loaded);
219 
220 	return 0;
221 }
222 
223 static const struct spi_device_id lattice_ecp3_id[] = {
224 	{ "ecp3-17", 0 },
225 	{ "ecp3-35", 0 },
226 	{ }
227 };
228 MODULE_DEVICE_TABLE(spi, lattice_ecp3_id);
229 
230 static struct spi_driver lattice_ecp3_driver = {
231 	.driver = {
232 		.name = "lattice-ecp3",
233 	},
234 	.probe = lattice_ecp3_probe,
235 	.remove = lattice_ecp3_remove,
236 	.id_table = lattice_ecp3_id,
237 };
238 
239 module_spi_driver(lattice_ecp3_driver);
240 
241 MODULE_AUTHOR("Stefan Roese <sr@denx.de>");
242 MODULE_DESCRIPTION("Lattice ECP3 FPGA configuration via SPI");
243 MODULE_LICENSE("GPL");
244 MODULE_FIRMWARE(FIRMWARE_NAME);
245