xref: /openbmc/u-boot/drivers/spi/cf_spi.c (revision dd1033e4)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *
4  * (C) Copyright 2000-2003
5  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
6  *
7  * Copyright (C) 2004-2009 Freescale Semiconductor, Inc.
8  * TsiChung Liew (Tsi-Chung.Liew@freescale.com)
9  */
10 
11 #include <common.h>
12 #include <spi.h>
13 #include <malloc.h>
14 #include <asm/immap.h>
15 
16 struct cf_spi_slave {
17 	struct spi_slave slave;
18 	uint baudrate;
19 	int charbit;
20 };
21 
22 extern void cfspi_port_conf(void);
23 extern int cfspi_claim_bus(uint bus, uint cs);
24 extern void cfspi_release_bus(uint bus, uint cs);
25 
26 DECLARE_GLOBAL_DATA_PTR;
27 
28 #ifndef CONFIG_SPI_IDLE_VAL
29 #if defined(CONFIG_SPI_MMC)
30 #define CONFIG_SPI_IDLE_VAL	0xFFFF
31 #else
32 #define CONFIG_SPI_IDLE_VAL	0x0
33 #endif
34 #endif
35 
36 #if defined(CONFIG_CF_DSPI)
37 /* DSPI specific mode */
38 #define SPI_MODE_MOD	0x00200000
39 #define SPI_DBLRATE	0x00100000
40 
41 static inline struct cf_spi_slave *to_cf_spi_slave(struct spi_slave *slave)
42 {
43 	return container_of(slave, struct cf_spi_slave, slave);
44 }
45 
46 static void cfspi_init(void)
47 {
48 	volatile dspi_t *dspi = (dspi_t *) MMAP_DSPI;
49 
50 	cfspi_port_conf();	/* port configuration */
51 
52 	dspi->mcr = DSPI_MCR_MSTR | DSPI_MCR_CSIS7 | DSPI_MCR_CSIS6 |
53 	    DSPI_MCR_CSIS5 | DSPI_MCR_CSIS4 | DSPI_MCR_CSIS3 |
54 	    DSPI_MCR_CSIS2 | DSPI_MCR_CSIS1 | DSPI_MCR_CSIS0 |
55 	    DSPI_MCR_CRXF | DSPI_MCR_CTXF;
56 
57 	/* Default setting in platform configuration */
58 #ifdef CONFIG_SYS_DSPI_CTAR0
59 	dspi->ctar[0] = CONFIG_SYS_DSPI_CTAR0;
60 #endif
61 #ifdef CONFIG_SYS_DSPI_CTAR1
62 	dspi->ctar[1] = CONFIG_SYS_DSPI_CTAR1;
63 #endif
64 #ifdef CONFIG_SYS_DSPI_CTAR2
65 	dspi->ctar[2] = CONFIG_SYS_DSPI_CTAR2;
66 #endif
67 #ifdef CONFIG_SYS_DSPI_CTAR3
68 	dspi->ctar[3] = CONFIG_SYS_DSPI_CTAR3;
69 #endif
70 #ifdef CONFIG_SYS_DSPI_CTAR4
71 	dspi->ctar[4] = CONFIG_SYS_DSPI_CTAR4;
72 #endif
73 #ifdef CONFIG_SYS_DSPI_CTAR5
74 	dspi->ctar[5] = CONFIG_SYS_DSPI_CTAR5;
75 #endif
76 #ifdef CONFIG_SYS_DSPI_CTAR6
77 	dspi->ctar[6] = CONFIG_SYS_DSPI_CTAR6;
78 #endif
79 #ifdef CONFIG_SYS_DSPI_CTAR7
80 	dspi->ctar[7] = CONFIG_SYS_DSPI_CTAR7;
81 #endif
82 }
83 
84 static void cfspi_tx(u32 ctrl, u16 data)
85 {
86 	volatile dspi_t *dspi = (dspi_t *) MMAP_DSPI;
87 
88 	while ((dspi->sr & 0x0000F000) >= 4) ;
89 
90 	dspi->tfr = (ctrl | data);
91 }
92 
93 static u16 cfspi_rx(void)
94 {
95 	volatile dspi_t *dspi = (dspi_t *) MMAP_DSPI;
96 
97 	while ((dspi->sr & 0x000000F0) == 0) ;
98 
99 	return (dspi->rfr & 0xFFFF);
100 }
101 
102 static int cfspi_xfer(struct spi_slave *slave, uint bitlen, const void *dout,
103 		      void *din, ulong flags)
104 {
105 	struct cf_spi_slave *cfslave = to_cf_spi_slave(slave);
106 	u16 *spi_rd16 = NULL, *spi_wr16 = NULL;
107 	u8 *spi_rd = NULL, *spi_wr = NULL;
108 	static u32 ctrl = 0;
109 	uint len = bitlen >> 3;
110 
111 	if (cfslave->charbit == 16) {
112 		bitlen >>= 1;
113 		spi_wr16 = (u16 *) dout;
114 		spi_rd16 = (u16 *) din;
115 	} else {
116 		spi_wr = (u8 *) dout;
117 		spi_rd = (u8 *) din;
118 	}
119 
120 	if ((flags & SPI_XFER_BEGIN) == SPI_XFER_BEGIN)
121 		ctrl |= DSPI_TFR_CONT;
122 
123 	ctrl = (ctrl & 0xFF000000) | ((1 << slave->cs) << 16);
124 
125 	if (len > 1) {
126 		int tmp_len = len - 1;
127 		while (tmp_len--) {
128 			if (dout != NULL) {
129 				if (cfslave->charbit == 16)
130 					cfspi_tx(ctrl, *spi_wr16++);
131 				else
132 					cfspi_tx(ctrl, *spi_wr++);
133 				cfspi_rx();
134 			}
135 
136 			if (din != NULL) {
137 				cfspi_tx(ctrl, CONFIG_SPI_IDLE_VAL);
138 				if (cfslave->charbit == 16)
139 					*spi_rd16++ = cfspi_rx();
140 				else
141 					*spi_rd++ = cfspi_rx();
142 			}
143 		}
144 
145 		len = 1;	/* remaining byte */
146 	}
147 
148 	if ((flags & SPI_XFER_END) == SPI_XFER_END)
149 		ctrl &= ~DSPI_TFR_CONT;
150 
151 	if (len) {
152 		if (dout != NULL) {
153 			if (cfslave->charbit == 16)
154 				cfspi_tx(ctrl, *spi_wr16);
155 			else
156 				cfspi_tx(ctrl, *spi_wr);
157 			cfspi_rx();
158 		}
159 
160 		if (din != NULL) {
161 			cfspi_tx(ctrl, CONFIG_SPI_IDLE_VAL);
162 			if (cfslave->charbit == 16)
163 				*spi_rd16 = cfspi_rx();
164 			else
165 				*spi_rd = cfspi_rx();
166 		}
167 	} else {
168 		/* dummy read */
169 		cfspi_tx(ctrl, CONFIG_SPI_IDLE_VAL);
170 		cfspi_rx();
171 	}
172 
173 	return 0;
174 }
175 
176 static struct spi_slave *cfspi_setup_slave(struct cf_spi_slave *cfslave,
177 					   uint mode)
178 {
179 	/*
180 	 * bit definition for mode:
181 	 * bit 31 - 28: Transfer size 3 to 16 bits
182 	 *     27 - 26: PCS to SCK delay prescaler
183 	 *     25 - 24: After SCK delay prescaler
184 	 *     23 - 22: Delay after transfer prescaler
185 	 *     21     : Allow overwrite for bit 31-22 and bit 20-8
186 	 *     20     : Double baud rate
187 	 *     19 - 16: PCS to SCK delay scaler
188 	 *     15 - 12: After SCK delay scaler
189 	 *     11 -  8: Delay after transfer scaler
190 	 *      7 -  0: SPI_CPHA, SPI_CPOL, SPI_LSB_FIRST
191 	 */
192 	volatile dspi_t *dspi = (dspi_t *) MMAP_DSPI;
193 	int prescaler[] = { 2, 3, 5, 7 };
194 	int scaler[] = {
195 		2, 4, 6, 8,
196 		16, 32, 64, 128,
197 		256, 512, 1024, 2048,
198 		4096, 8192, 16384, 32768
199 	};
200 	int i, j, pbrcnt, brcnt, diff, tmp, dbr = 0;
201 	int best_i, best_j, bestmatch = 0x7FFFFFFF, baud_speed;
202 	u32 bus_setup = 0;
203 
204 	tmp = (prescaler[3] * scaler[15]);
205 	/* Maximum and minimum baudrate it can handle */
206 	if ((cfslave->baudrate > (gd->bus_clk >> 1)) ||
207 	    (cfslave->baudrate < (gd->bus_clk / tmp))) {
208 		printf("Exceed baudrate limitation: Max %d - Min %d\n",
209 		       (int)(gd->bus_clk >> 1), (int)(gd->bus_clk / tmp));
210 		return NULL;
211 	}
212 
213 	/* Activate Double Baud when it exceed 1/4 the bus clk */
214 	if ((CONFIG_SYS_DSPI_CTAR0 & DSPI_CTAR_DBR) ||
215 	    (cfslave->baudrate > (gd->bus_clk / (prescaler[0] * scaler[0])))) {
216 		bus_setup |= DSPI_CTAR_DBR;
217 		dbr = 1;
218 	}
219 
220 	if (mode & SPI_CPOL)
221 		bus_setup |= DSPI_CTAR_CPOL;
222 	if (mode & SPI_CPHA)
223 		bus_setup |= DSPI_CTAR_CPHA;
224 	if (mode & SPI_LSB_FIRST)
225 		bus_setup |= DSPI_CTAR_LSBFE;
226 
227 	/* Overwrite default value set in platform configuration file */
228 	if (mode & SPI_MODE_MOD) {
229 
230 		if ((mode & 0xF0000000) == 0)
231 			bus_setup |=
232 			    dspi->ctar[cfslave->slave.bus] & 0x78000000;
233 		else
234 			bus_setup |= ((mode & 0xF0000000) >> 1);
235 
236 		/*
237 		 * Check to see if it is enabled by default in platform
238 		 * config, or manual setting passed by mode parameter
239 		 */
240 		if (mode & SPI_DBLRATE) {
241 			bus_setup |= DSPI_CTAR_DBR;
242 			dbr = 1;
243 		}
244 		bus_setup |= (mode & 0x0FC00000) >> 4;	/* PSCSCK, PASC, PDT */
245 		bus_setup |= (mode & 0x000FFF00) >> 4;	/* CSSCK, ASC, DT */
246 	} else
247 		bus_setup |= (dspi->ctar[cfslave->slave.bus] & 0x78FCFFF0);
248 
249 	cfslave->charbit =
250 	    ((dspi->ctar[cfslave->slave.bus] & 0x78000000) ==
251 	     0x78000000) ? 16 : 8;
252 
253 	pbrcnt = sizeof(prescaler) / sizeof(int);
254 	brcnt = sizeof(scaler) / sizeof(int);
255 
256 	/* baudrate calculation - to closer value, may not be exact match */
257 	for (best_i = 0, best_j = 0, i = 0; i < pbrcnt; i++) {
258 		baud_speed = gd->bus_clk / prescaler[i];
259 		for (j = 0; j < brcnt; j++) {
260 			tmp = (baud_speed / scaler[j]) * (1 + dbr);
261 
262 			if (tmp > cfslave->baudrate)
263 				diff = tmp - cfslave->baudrate;
264 			else
265 				diff = cfslave->baudrate - tmp;
266 
267 			if (diff < bestmatch) {
268 				bestmatch = diff;
269 				best_i = i;
270 				best_j = j;
271 			}
272 		}
273 	}
274 	bus_setup |= (DSPI_CTAR_PBR(best_i) | DSPI_CTAR_BR(best_j));
275 	dspi->ctar[cfslave->slave.bus] = bus_setup;
276 
277 	return &cfslave->slave;
278 }
279 #endif				/* CONFIG_CF_DSPI */
280 
281 #ifdef CONFIG_CMD_SPI
282 int spi_cs_is_valid(unsigned int bus, unsigned int cs)
283 {
284 	if (((cs >= 0) && (cs < 8)) && ((bus >= 0) && (bus < 8)))
285 		return 1;
286 	else
287 		return 0;
288 }
289 
290 void spi_init(void)
291 {
292 	cfspi_init();
293 }
294 
295 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
296 				  unsigned int max_hz, unsigned int mode)
297 {
298 	struct cf_spi_slave *cfslave;
299 
300 	if (!spi_cs_is_valid(bus, cs))
301 		return NULL;
302 
303 	cfslave = spi_alloc_slave(struct cf_spi_slave, bus, cs);
304 	if (!cfslave)
305 		return NULL;
306 
307 	cfslave->baudrate = max_hz;
308 
309 	/* specific setup */
310 	return cfspi_setup_slave(cfslave, mode);
311 }
312 
313 void spi_free_slave(struct spi_slave *slave)
314 {
315 	struct cf_spi_slave *cfslave = to_cf_spi_slave(slave);
316 
317 	free(cfslave);
318 }
319 
320 int spi_claim_bus(struct spi_slave *slave)
321 {
322 	return cfspi_claim_bus(slave->bus, slave->cs);
323 }
324 
325 void spi_release_bus(struct spi_slave *slave)
326 {
327 	cfspi_release_bus(slave->bus, slave->cs);
328 }
329 
330 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
331 	     void *din, unsigned long flags)
332 {
333 	return cfspi_xfer(slave, bitlen, dout, din, flags);
334 }
335 #endif				/* CONFIG_CMD_SPI */
336