xref: /openbmc/u-boot/drivers/spi/cadence_qspi.c (revision 86bedaeb)
1 /*
2  * Copyright (C) 2012
3  * Altera Corporation <www.altera.com>
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 #include <common.h>
9 #include <dm.h>
10 #include <fdtdec.h>
11 #include <malloc.h>
12 #include <spi.h>
13 #include <asm/errno.h>
14 #include "cadence_qspi.h"
15 
16 #define CQSPI_STIG_READ			0
17 #define CQSPI_STIG_WRITE		1
18 #define CQSPI_INDIRECT_READ		2
19 #define CQSPI_INDIRECT_WRITE		3
20 
21 DECLARE_GLOBAL_DATA_PTR;
22 
23 static int cadence_spi_write_speed(struct udevice *bus, uint hz)
24 {
25 	struct cadence_spi_platdata *plat = bus->platdata;
26 	struct cadence_spi_priv *priv = dev_get_priv(bus);
27 
28 	cadence_qspi_apb_config_baudrate_div(priv->regbase,
29 					     CONFIG_CQSPI_REF_CLK, hz);
30 
31 	/* Reconfigure delay timing if speed is changed. */
32 	cadence_qspi_apb_delay(priv->regbase, CONFIG_CQSPI_REF_CLK, hz,
33 			       plat->tshsl_ns, plat->tsd2d_ns,
34 			       plat->tchsh_ns, plat->tslch_ns);
35 
36 	return 0;
37 }
38 
39 /* Calibration sequence to determine the read data capture delay register */
40 static int spi_calibration(struct udevice *bus)
41 {
42 	struct cadence_spi_platdata *plat = bus->platdata;
43 	struct cadence_spi_priv *priv = dev_get_priv(bus);
44 	void *base = priv->regbase;
45 	u8 opcode_rdid = 0x9F;
46 	unsigned int idcode = 0, temp = 0;
47 	int err = 0, i, range_lo = -1, range_hi = -1;
48 
49 	/* start with slowest clock (1 MHz) */
50 	cadence_spi_write_speed(bus, 1000000);
51 
52 	/* configure the read data capture delay register to 0 */
53 	cadence_qspi_apb_readdata_capture(base, 1, 0);
54 
55 	/* Enable QSPI */
56 	cadence_qspi_apb_controller_enable(base);
57 
58 	/* read the ID which will be our golden value */
59 	err = cadence_qspi_apb_command_read(base, 1, &opcode_rdid,
60 		3, (u8 *)&idcode);
61 	if (err) {
62 		puts("SF: Calibration failed (read)\n");
63 		return err;
64 	}
65 
66 	/* use back the intended clock and find low range */
67 	cadence_spi_write_speed(bus, plat->max_hz);
68 	for (i = 0; i < CQSPI_READ_CAPTURE_MAX_DELAY; i++) {
69 		/* Disable QSPI */
70 		cadence_qspi_apb_controller_disable(base);
71 
72 		/* reconfigure the read data capture delay register */
73 		cadence_qspi_apb_readdata_capture(base, 1, i);
74 
75 		/* Enable back QSPI */
76 		cadence_qspi_apb_controller_enable(base);
77 
78 		/* issue a RDID to get the ID value */
79 		err = cadence_qspi_apb_command_read(base, 1, &opcode_rdid,
80 			3, (u8 *)&temp);
81 		if (err) {
82 			puts("SF: Calibration failed (read)\n");
83 			return err;
84 		}
85 
86 		/* search for range lo */
87 		if (range_lo == -1 && temp == idcode) {
88 			range_lo = i;
89 			continue;
90 		}
91 
92 		/* search for range hi */
93 		if (range_lo != -1 && temp != idcode) {
94 			range_hi = i - 1;
95 			break;
96 		}
97 		range_hi = i;
98 	}
99 
100 	if (range_lo == -1) {
101 		puts("SF: Calibration failed (low range)\n");
102 		return err;
103 	}
104 
105 	/* Disable QSPI for subsequent initialization */
106 	cadence_qspi_apb_controller_disable(base);
107 
108 	/* configure the final value for read data capture delay register */
109 	cadence_qspi_apb_readdata_capture(base, 1, (range_hi + range_lo) / 2);
110 	debug("SF: Read data capture delay calibrated to %i (%i - %i)\n",
111 	      (range_hi + range_lo) / 2, range_lo, range_hi);
112 
113 	/* just to ensure we do once only when speed or chip select change */
114 	priv->qspi_calibrated_hz = plat->max_hz;
115 	priv->qspi_calibrated_cs = spi_chip_select(bus);
116 
117 	return 0;
118 }
119 
120 static int cadence_spi_set_speed(struct udevice *bus, uint hz)
121 {
122 	struct cadence_spi_platdata *plat = bus->platdata;
123 	struct cadence_spi_priv *priv = dev_get_priv(bus);
124 	int err;
125 
126 	/* Disable QSPI */
127 	cadence_qspi_apb_controller_disable(priv->regbase);
128 
129 	cadence_spi_write_speed(bus, hz);
130 
131 	/* Calibration required for different SCLK speed or chip select */
132 	if (priv->qspi_calibrated_hz != plat->max_hz ||
133 	    priv->qspi_calibrated_cs != spi_chip_select(bus)) {
134 		err = spi_calibration(bus);
135 		if (err)
136 			return err;
137 	}
138 
139 	/* Enable QSPI */
140 	cadence_qspi_apb_controller_enable(priv->regbase);
141 
142 	debug("%s: speed=%d\n", __func__, hz);
143 
144 	return 0;
145 }
146 
147 static int cadence_spi_probe(struct udevice *bus)
148 {
149 	struct cadence_spi_platdata *plat = bus->platdata;
150 	struct cadence_spi_priv *priv = dev_get_priv(bus);
151 
152 	priv->regbase = plat->regbase;
153 	priv->ahbbase = plat->ahbbase;
154 
155 	if (!priv->qspi_is_init) {
156 		cadence_qspi_apb_controller_init(plat);
157 		priv->qspi_is_init = 1;
158 	}
159 
160 	return 0;
161 }
162 
163 static int cadence_spi_set_mode(struct udevice *bus, uint mode)
164 {
165 	struct cadence_spi_priv *priv = dev_get_priv(bus);
166 	unsigned int clk_pol = (mode & SPI_CPOL) ? 1 : 0;
167 	unsigned int clk_pha = (mode & SPI_CPHA) ? 1 : 0;
168 
169 	/* Disable QSPI */
170 	cadence_qspi_apb_controller_disable(priv->regbase);
171 
172 	/* Set SPI mode */
173 	cadence_qspi_apb_set_clk_mode(priv->regbase, clk_pol, clk_pha);
174 
175 	/* Enable QSPI */
176 	cadence_qspi_apb_controller_enable(priv->regbase);
177 
178 	return 0;
179 }
180 
181 static int cadence_spi_xfer(struct udevice *dev, unsigned int bitlen,
182 			    const void *dout, void *din, unsigned long flags)
183 {
184 	struct udevice *bus = dev->parent;
185 	struct cadence_spi_platdata *plat = bus->platdata;
186 	struct cadence_spi_priv *priv = dev_get_priv(bus);
187 	void *base = priv->regbase;
188 	u8 *cmd_buf = priv->cmd_buf;
189 	size_t data_bytes;
190 	int err = 0;
191 	u32 mode = CQSPI_STIG_WRITE;
192 
193 	if (flags & SPI_XFER_BEGIN) {
194 		/* copy command to local buffer */
195 		priv->cmd_len = bitlen / 8;
196 		memcpy(cmd_buf, dout, priv->cmd_len);
197 	}
198 
199 	if (flags == (SPI_XFER_BEGIN | SPI_XFER_END)) {
200 		/* if start and end bit are set, the data bytes is 0. */
201 		data_bytes = 0;
202 	} else {
203 		data_bytes = bitlen / 8;
204 	}
205 	debug("%s: len=%d [bytes]\n", __func__, data_bytes);
206 
207 	/* Set Chip select */
208 	cadence_qspi_apb_chipselect(base, spi_chip_select(dev),
209 				    CONFIG_CQSPI_DECODER);
210 
211 	if ((flags & SPI_XFER_END) || (flags == 0)) {
212 		if (priv->cmd_len == 0) {
213 			printf("QSPI: Error, command is empty.\n");
214 			return -1;
215 		}
216 
217 		if (din && data_bytes) {
218 			/* read */
219 			/* Use STIG if no address. */
220 			if (!CQSPI_IS_ADDR(priv->cmd_len))
221 				mode = CQSPI_STIG_READ;
222 			else
223 				mode = CQSPI_INDIRECT_READ;
224 		} else if (dout && !(flags & SPI_XFER_BEGIN)) {
225 			/* write */
226 			if (!CQSPI_IS_ADDR(priv->cmd_len))
227 				mode = CQSPI_STIG_WRITE;
228 			else
229 				mode = CQSPI_INDIRECT_WRITE;
230 		}
231 
232 		switch (mode) {
233 		case CQSPI_STIG_READ:
234 			err = cadence_qspi_apb_command_read(
235 				base, priv->cmd_len, cmd_buf,
236 				data_bytes, din);
237 
238 		break;
239 		case CQSPI_STIG_WRITE:
240 			err = cadence_qspi_apb_command_write(base,
241 				priv->cmd_len, cmd_buf,
242 				data_bytes, dout);
243 		break;
244 		case CQSPI_INDIRECT_READ:
245 			err = cadence_qspi_apb_indirect_read_setup(plat,
246 				priv->cmd_len, cmd_buf);
247 			if (!err) {
248 				err = cadence_qspi_apb_indirect_read_execute
249 				(plat, data_bytes, din);
250 			}
251 		break;
252 		case CQSPI_INDIRECT_WRITE:
253 			err = cadence_qspi_apb_indirect_write_setup
254 				(plat, priv->cmd_len, cmd_buf);
255 			if (!err) {
256 				err = cadence_qspi_apb_indirect_write_execute
257 				(plat, data_bytes, dout);
258 			}
259 		break;
260 		default:
261 			err = -1;
262 			break;
263 		}
264 
265 		if (flags & SPI_XFER_END) {
266 			/* clear command buffer */
267 			memset(cmd_buf, 0, sizeof(priv->cmd_buf));
268 			priv->cmd_len = 0;
269 		}
270 	}
271 
272 	return err;
273 }
274 
275 static int cadence_spi_ofdata_to_platdata(struct udevice *bus)
276 {
277 	struct cadence_spi_platdata *plat = bus->platdata;
278 	const void *blob = gd->fdt_blob;
279 	int node = bus->of_offset;
280 	int subnode;
281 	u32 data[4];
282 	int ret;
283 
284 	/* 2 base addresses are needed, lets get them from the DT */
285 	ret = fdtdec_get_int_array(blob, node, "reg", data, ARRAY_SIZE(data));
286 	if (ret) {
287 		printf("Error: Can't get base addresses (ret=%d)!\n", ret);
288 		return -ENODEV;
289 	}
290 
291 	plat->regbase = (void *)data[0];
292 	plat->ahbbase = (void *)data[2];
293 
294 	/* Use 500KHz as a suitable default */
295 	plat->max_hz = fdtdec_get_int(blob, node, "spi-max-frequency",
296 				      500000);
297 
298 	/* All other paramters are embedded in the child node */
299 	subnode = fdt_first_subnode(blob, node);
300 	if (subnode < 0) {
301 		printf("Error: subnode with SPI flash config missing!\n");
302 		return -ENODEV;
303 	}
304 
305 	/* Read other parameters from DT */
306 	plat->page_size = fdtdec_get_int(blob, subnode, "page-size", 256);
307 	plat->block_size = fdtdec_get_int(blob, subnode, "block-size", 16);
308 	plat->tshsl_ns = fdtdec_get_int(blob, subnode, "tshsl-ns", 200);
309 	plat->tsd2d_ns = fdtdec_get_int(blob, subnode, "tsd2d-ns", 255);
310 	plat->tchsh_ns = fdtdec_get_int(blob, subnode, "tchsh-ns", 20);
311 	plat->tslch_ns = fdtdec_get_int(blob, subnode, "tslch-ns", 20);
312 
313 	debug("%s: regbase=%p ahbbase=%p max-frequency=%d page-size=%d\n",
314 	      __func__, plat->regbase, plat->ahbbase, plat->max_hz,
315 	      plat->page_size);
316 
317 	return 0;
318 }
319 
320 static const struct dm_spi_ops cadence_spi_ops = {
321 	.xfer		= cadence_spi_xfer,
322 	.set_speed	= cadence_spi_set_speed,
323 	.set_mode	= cadence_spi_set_mode,
324 	/*
325 	 * cs_info is not needed, since we require all chip selects to be
326 	 * in the device tree explicitly
327 	 */
328 };
329 
330 static const struct udevice_id cadence_spi_ids[] = {
331 	{ .compatible = "cadence,qspi" },
332 	{ }
333 };
334 
335 U_BOOT_DRIVER(cadence_spi) = {
336 	.name = "cadence_spi",
337 	.id = UCLASS_SPI,
338 	.of_match = cadence_spi_ids,
339 	.ops = &cadence_spi_ops,
340 	.ofdata_to_platdata = cadence_spi_ofdata_to_platdata,
341 	.platdata_auto_alloc_size = sizeof(struct cadence_spi_platdata),
342 	.priv_auto_alloc_size = sizeof(struct cadence_spi_priv),
343 	.probe = cadence_spi_probe,
344 };
345