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Stefan Roese3fda4ef2016-05-19 15:56:44 +02001/*
2 * Copyright (C) 2015 Marvell International Ltd.
3 *
4 * Copyright (C) 2016 Stefan Roese <sr@denx.de>
5 *
6 * SPDX-License-Identifier: GPL-2.0+
7 */
8
9#include <common.h>
10#include <dm.h>
11#include <malloc.h>
12#include <spi.h>
13#include <wait_bit.h>
14#include <asm/io.h>
15
16DECLARE_GLOBAL_DATA_PTR;
17
18#define MVEBU_SPI_A3700_XFER_RDY BIT(1)
19#define MVEBU_SPI_A3700_FIFO_FLUSH BIT(9)
20#define MVEBU_SPI_A3700_BYTE_LEN BIT(5)
21#define MVEBU_SPI_A3700_CLK_PHA BIT(6)
22#define MVEBU_SPI_A3700_CLK_POL BIT(7)
23#define MVEBU_SPI_A3700_FIFO_EN BIT(17)
24#define MVEBU_SPI_A3700_SPI_EN_0 BIT(16)
25#define MVEBU_SPI_A3700_CLK_PRESCALE_BIT 0
26#define MVEBU_SPI_A3700_CLK_PRESCALE_MASK \
27 (0x1f << MVEBU_SPI_A3700_CLK_PRESCALE_BIT)
28
29/* SPI registers */
30struct spi_reg {
31 u32 ctrl; /* 0x10600 */
32 u32 cfg; /* 0x10604 */
33 u32 dout; /* 0x10608 */
34 u32 din; /* 0x1060c */
35};
36
37struct mvebu_spi_platdata {
38 struct spi_reg *spireg;
39 unsigned int frequency;
40 unsigned int clock;
41};
42
43static void spi_cs_activate(struct spi_reg *reg, int cs)
44{
45 setbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
46}
47
48static void spi_cs_deactivate(struct spi_reg *reg, int cs)
49{
50 clrbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
51}
52
53/**
54 * spi_legacy_shift_byte() - triggers the real SPI transfer
55 * @bytelen: Indicate how many bytes to transfer.
56 * @dout: Buffer address of what to send.
57 * @din: Buffer address of where to receive.
58 *
59 * This function triggers the real SPI transfer in legacy mode. It
60 * will shift out char buffer from @dout, and shift in char buffer to
61 * @din, if necessary.
62 *
63 * This function assumes that only one byte is shifted at one time.
64 * However, it is not its responisbility to set the transfer type to
65 * one-byte. Also, it does not guarantee that it will work if transfer
66 * type becomes two-byte. See spi_set_legacy() for details.
67 *
68 * In legacy mode, simply write to the SPI_DOUT register will trigger
69 * the transfer.
70 *
71 * If @dout == NULL, which means no actual data needs to be sent out,
72 * then the function will shift out 0x00 in order to shift in data.
73 * The XFER_RDY flag is checked every time before accessing SPI_DOUT
74 * and SPI_DIN register.
75 *
76 * The number of transfers to be triggerred is decided by @bytelen.
77 *
78 * Return: 0 - cool
79 * -ETIMEDOUT - XFER_RDY flag timeout
80 */
81static int spi_legacy_shift_byte(struct spi_reg *reg, unsigned int bytelen,
82 const void *dout, void *din)
83{
84 const u8 *dout_8;
85 u8 *din_8;
86 int ret;
87
88 /* Use 0x00 as dummy dout */
89 const u8 dummy_dout = 0x0;
90 u32 pending_dout = 0x0;
91
92 /* dout_8: pointer of current dout */
93 dout_8 = dout;
94 /* din_8: pointer of current din */
95 din_8 = din;
96
97 while (bytelen) {
98 ret = wait_for_bit(__func__, &reg->ctrl,
99 MVEBU_SPI_A3700_XFER_RDY, true, 100, false);
100 if (ret)
101 return ret;
102
103 if (dout)
104 pending_dout = (u32)*dout_8;
105 else
106 pending_dout = (u32)dummy_dout;
107
108 /* Trigger the xfer */
109 writel(pending_dout, &reg->dout);
110
111 if (din) {
112 ret = wait_for_bit(__func__, &reg->ctrl,
113 MVEBU_SPI_A3700_XFER_RDY,
114 true, 100, false);
115 if (ret)
116 return ret;
117
118 /* Read what is transferred in */
119 *din_8 = (u8)readl(&reg->din);
120 }
121
122 /* Don't increment the current pointer if NULL */
123 if (dout)
124 dout_8++;
125 if (din)
126 din_8++;
127
128 bytelen--;
129 }
130
131 return 0;
132}
133
134static int mvebu_spi_xfer(struct udevice *dev, unsigned int bitlen,
135 const void *dout, void *din, unsigned long flags)
136{
137 struct udevice *bus = dev->parent;
138 struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
139 struct spi_reg *reg = plat->spireg;
140 unsigned int bytelen;
141 int ret;
142
143 bytelen = bitlen / 8;
144
145 if (dout && din)
146 debug("This is a duplex transfer.\n");
147
148 /* Activate CS */
149 if (flags & SPI_XFER_BEGIN) {
150 debug("SPI: activate cs.\n");
151 spi_cs_activate(reg, spi_chip_select(dev));
152 }
153
154 /* Send and/or receive */
155 if (dout || din) {
156 ret = spi_legacy_shift_byte(reg, bytelen, dout, din);
157 if (ret)
158 return ret;
159 }
160
161 /* Deactivate CS */
162 if (flags & SPI_XFER_END) {
163 ret = wait_for_bit(__func__, &reg->ctrl,
164 MVEBU_SPI_A3700_XFER_RDY, true, 100, false);
165 if (ret)
166 return ret;
167
168 debug("SPI: deactivate cs.\n");
169 spi_cs_deactivate(reg, spi_chip_select(dev));
170 }
171
172 return 0;
173}
174
175static int mvebu_spi_set_speed(struct udevice *bus, uint hz)
176{
177 struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
178 struct spi_reg *reg = plat->spireg;
179 u32 data;
180
181 data = readl(&reg->cfg);
182
183 /* Set Prescaler */
184 data &= ~MVEBU_SPI_A3700_CLK_PRESCALE_MASK;
185
186 /* Calculate Prescaler = (spi_input_freq / spi_max_freq) */
187 if (hz > plat->frequency)
188 hz = plat->frequency;
189 data |= plat->clock / hz;
190
191 writel(data, &reg->cfg);
192
193 return 0;
194}
195
196static int mvebu_spi_set_mode(struct udevice *bus, uint mode)
197{
198 struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
199 struct spi_reg *reg = plat->spireg;
200
201 /*
202 * Set SPI polarity
203 * 0: Serial interface clock is low when inactive
204 * 1: Serial interface clock is high when inactive
205 */
206 if (mode & SPI_CPOL)
207 setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
208 else
209 clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
210 if (mode & SPI_CPHA)
211 setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
212 else
213 clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
214
215 return 0;
216}
217
218static int mvebu_spi_probe(struct udevice *bus)
219{
220 struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
221 struct spi_reg *reg = plat->spireg;
222 u32 data;
223 int ret;
224
225 /*
226 * Settings SPI controller to be working in legacy mode, which
227 * means use only DO pin (I/O 1) for Data Out, and DI pin (I/O 0)
228 * for Data In.
229 */
230
231 /* Flush read/write FIFO */
232 data = readl(&reg->cfg);
233 writel(data | MVEBU_SPI_A3700_FIFO_FLUSH, &reg->cfg);
234 ret = wait_for_bit(__func__, &reg->cfg, MVEBU_SPI_A3700_FIFO_FLUSH,
235 false, 1000, false);
236 if (ret)
237 return ret;
238
239 /* Disable FIFO mode */
240 data &= ~MVEBU_SPI_A3700_FIFO_EN;
241
242 /* Always shift 1 byte at a time */
243 data &= ~MVEBU_SPI_A3700_BYTE_LEN;
244
245 writel(data, &reg->cfg);
246
247 return 0;
248}
249
250static int mvebu_spi_ofdata_to_platdata(struct udevice *bus)
251{
252 struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
253
254 plat->spireg = (struct spi_reg *)dev_get_addr(bus);
255
256 /*
257 * FIXME
258 * Right now, mvebu does not have a clock infrastructure in U-Boot
259 * which should be used to query the input clock to the SPI
260 * controller. Once this clock driver is integrated into U-Boot
261 * it should be used to read the input clock and the DT property
262 * can be removed.
263 */
Simon Glasse160f7d2017-01-17 16:52:55 -0700264 plat->clock = fdtdec_get_int(gd->fdt_blob, dev_of_offset(bus),
Stefan Roese3fda4ef2016-05-19 15:56:44 +0200265 "clock-frequency", 160000);
Simon Glasse160f7d2017-01-17 16:52:55 -0700266 plat->frequency = fdtdec_get_int(gd->fdt_blob, dev_of_offset(bus),
Stefan Roese3fda4ef2016-05-19 15:56:44 +0200267 "spi-max-frequency", 40000);
268
269 return 0;
270}
271
272static const struct dm_spi_ops mvebu_spi_ops = {
273 .xfer = mvebu_spi_xfer,
274 .set_speed = mvebu_spi_set_speed,
275 .set_mode = mvebu_spi_set_mode,
276 /*
277 * cs_info is not needed, since we require all chip selects to be
278 * in the device tree explicitly
279 */
280};
281
282static const struct udevice_id mvebu_spi_ids[] = {
283 { .compatible = "marvell,armada-3700-spi" },
284 { }
285};
286
287U_BOOT_DRIVER(mvebu_spi) = {
288 .name = "mvebu_spi",
289 .id = UCLASS_SPI,
290 .of_match = mvebu_spi_ids,
291 .ops = &mvebu_spi_ops,
292 .ofdata_to_platdata = mvebu_spi_ofdata_to_platdata,
293 .platdata_auto_alloc_size = sizeof(struct mvebu_spi_platdata),
294 .probe = mvebu_spi_probe,
295};