tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2011, 2012 Cavium, Inc.
7 */
8
9#include <linux/platform_device.h>
10#include <linux/interrupt.h>
11#include <linux/spi/spi.h>
12#include <linux/module.h>
13#include <linux/delay.h>
14#include <linux/init.h>
15#include <linux/io.h>
16#include <linux/of.h>
17
18#include <asm/octeon/octeon.h>
19#include <asm/octeon/cvmx-mpi-defs.h>
20
21#define OCTEON_SPI_CFG 0
22#define OCTEON_SPI_STS 0x08
23#define OCTEON_SPI_TX 0x10
24#define OCTEON_SPI_DAT0 0x80
25
26#define OCTEON_SPI_MAX_BYTES 9
27
28#define OCTEON_SPI_MAX_CLOCK_HZ 16000000
29
30struct octeon_spi {
31 struct spi_master *my_master;
32 u64 register_base;
33 u64 last_cfg;
34 u64 cs_enax;
35};
36
37struct octeon_spi_setup {
38 u32 max_speed_hz;
39 u8 chip_select;
40 u8 mode;
41 u8 bits_per_word;
42};
43
44static void octeon_spi_wait_ready(struct octeon_spi *p)
45{
46 union cvmx_mpi_sts mpi_sts;
47 unsigned int loops = 0;
48
49 do {
50 if (loops++)
51 __delay(500);
52 mpi_sts.u64 = cvmx_read_csr(p->register_base + OCTEON_SPI_STS);
53 } while (mpi_sts.s.busy);
54}
55
56static int octeon_spi_do_transfer(struct octeon_spi *p,
57 struct spi_message *msg,
58 struct spi_transfer *xfer,
59 bool last_xfer)
60{
61 union cvmx_mpi_cfg mpi_cfg;
62 union cvmx_mpi_tx mpi_tx;
63 unsigned int clkdiv;
64 unsigned int speed_hz;
65 int mode;
66 bool cpha, cpol;
67 int bits_per_word;
68 const u8 *tx_buf;
69 u8 *rx_buf;
70 int len;
71 int i;
72
73 struct octeon_spi_setup *msg_setup = spi_get_ctldata(msg->spi);
74
75 speed_hz = msg_setup->max_speed_hz;
76 mode = msg_setup->mode;
77 cpha = mode & SPI_CPHA;
78 cpol = mode & SPI_CPOL;
79 bits_per_word = msg_setup->bits_per_word;
80
81 if (xfer->speed_hz)
82 speed_hz = xfer->speed_hz;
83 if (xfer->bits_per_word)
84 bits_per_word = xfer->bits_per_word;
85
86 if (speed_hz > OCTEON_SPI_MAX_CLOCK_HZ)
87 speed_hz = OCTEON_SPI_MAX_CLOCK_HZ;
88
89 clkdiv = octeon_get_io_clock_rate() / (2 * speed_hz);
90
91 mpi_cfg.u64 = 0;
92
93 mpi_cfg.s.clkdiv = clkdiv;
94 mpi_cfg.s.cshi = (mode & SPI_CS_HIGH) ? 1 : 0;
95 mpi_cfg.s.lsbfirst = (mode & SPI_LSB_FIRST) ? 1 : 0;
96 mpi_cfg.s.wireor = (mode & SPI_3WIRE) ? 1 : 0;
97 mpi_cfg.s.idlelo = cpha != cpol;
98 mpi_cfg.s.cslate = cpha ? 1 : 0;
99 mpi_cfg.s.enable = 1;
100
101 if (msg_setup->chip_select < 4)
102 p->cs_enax |= 1ull << (12 + msg_setup->chip_select);
103 mpi_cfg.u64 |= p->cs_enax;
104
105 if (mpi_cfg.u64 != p->last_cfg) {
106 p->last_cfg = mpi_cfg.u64;
107 cvmx_write_csr(p->register_base + OCTEON_SPI_CFG, mpi_cfg.u64);
108 }
109 tx_buf = xfer->tx_buf;
110 rx_buf = xfer->rx_buf;
111 len = xfer->len;
112 while (len > OCTEON_SPI_MAX_BYTES) {
113 for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) {
114 u8 d;
115 if (tx_buf)
116 d = *tx_buf++;
117 else
118 d = 0;
119 cvmx_write_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i), d);
120 }
121 mpi_tx.u64 = 0;
122 mpi_tx.s.csid = msg_setup->chip_select;
123 mpi_tx.s.leavecs = 1;
124 mpi_tx.s.txnum = tx_buf ? OCTEON_SPI_MAX_BYTES : 0;
125 mpi_tx.s.totnum = OCTEON_SPI_MAX_BYTES;
126 cvmx_write_csr(p->register_base + OCTEON_SPI_TX, mpi_tx.u64);
127
128 octeon_spi_wait_ready(p);
129 if (rx_buf)
130 for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) {
131 u64 v = cvmx_read_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i));
132 *rx_buf++ = (u8)v;
133 }
134 len -= OCTEON_SPI_MAX_BYTES;
135 }
136
137 for (i = 0; i < len; i++) {
138 u8 d;
139 if (tx_buf)
140 d = *tx_buf++;
141 else
142 d = 0;
143 cvmx_write_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i), d);
144 }
145
146 mpi_tx.u64 = 0;
147 mpi_tx.s.csid = msg_setup->chip_select;
148 if (last_xfer)
149 mpi_tx.s.leavecs = xfer->cs_change;
150 else
151 mpi_tx.s.leavecs = !xfer->cs_change;
152 mpi_tx.s.txnum = tx_buf ? len : 0;
153 mpi_tx.s.totnum = len;
154 cvmx_write_csr(p->register_base + OCTEON_SPI_TX, mpi_tx.u64);
155
156 octeon_spi_wait_ready(p);
157 if (rx_buf)
158 for (i = 0; i < len; i++) {
159 u64 v = cvmx_read_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i));
160 *rx_buf++ = (u8)v;
161 }
162
163 if (xfer->delay_usecs)
164 udelay(xfer->delay_usecs);
165
166 return xfer->len;
167}
168
169static int octeon_spi_validate_bpw(struct spi_device *spi, u32 speed)
170{
171 switch (speed) {
172 case 8:
173 break;
174 default:
175 dev_err(&spi->dev, "Error: %d bits per word not supported\n",
176 speed);
177 return -EINVAL;
178 }
179 return 0;
180}
181
182static int octeon_spi_transfer_one_message(struct spi_master *master,
183 struct spi_message *msg)
184{
185 struct octeon_spi *p = spi_master_get_devdata(master);
186 unsigned int total_len = 0;
187 int status = 0;
188 struct spi_transfer *xfer;
189
190 /*
191 * We better have set the configuration via a call to .setup
192 * before we get here.
193 */
194 if (spi_get_ctldata(msg->spi) == NULL) {
195 status = -EINVAL;
196 goto err;
197 }
198
199 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
200 if (xfer->bits_per_word) {
201 status = octeon_spi_validate_bpw(msg->spi,
202 xfer->bits_per_word);
203 if (status)
204 goto err;
205 }
206 }
207
208 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
209 bool last_xfer = &xfer->transfer_list == msg->transfers.prev;
210 int r = octeon_spi_do_transfer(p, msg, xfer, last_xfer);
211 if (r < 0) {
212 status = r;
213 goto err;
214 }
215 total_len += r;
216 }
217err:
218 msg->status = status;
219 msg->actual_length = total_len;
220 spi_finalize_current_message(master);
221 return status;
222}
223
224static struct octeon_spi_setup *octeon_spi_new_setup(struct spi_device *spi)
225{
226 struct octeon_spi_setup *setup = kzalloc(sizeof(*setup), GFP_KERNEL);
227 if (!setup)
228 return NULL;
229
230 setup->max_speed_hz = spi->max_speed_hz;
231 setup->chip_select = spi->chip_select;
232 setup->mode = spi->mode;
233 setup->bits_per_word = spi->bits_per_word;
234 return setup;
235}
236
237static int octeon_spi_setup(struct spi_device *spi)
238{
239 int r;
240 struct octeon_spi_setup *new_setup;
241 struct octeon_spi_setup *old_setup = spi_get_ctldata(spi);
242
243 r = octeon_spi_validate_bpw(spi, spi->bits_per_word);
244 if (r)
245 return r;
246
247 new_setup = octeon_spi_new_setup(spi);
248 if (!new_setup)
249 return -ENOMEM;
250
251 spi_set_ctldata(spi, new_setup);
252 kfree(old_setup);
253
254 return 0;
255}
256
257static void octeon_spi_cleanup(struct spi_device *spi)
258{
259 struct octeon_spi_setup *old_setup = spi_get_ctldata(spi);
260 spi_set_ctldata(spi, NULL);
261 kfree(old_setup);
262}
263
264static int octeon_spi_nop_transfer_hardware(struct spi_master *master)
265{
266 return 0;
267}
268
269static int octeon_spi_probe(struct platform_device *pdev)
270{
271
272 struct resource *res_mem;
273 struct spi_master *master;
274 struct octeon_spi *p;
275 int err = -ENOENT;
276
277 master = spi_alloc_master(&pdev->dev, sizeof(struct octeon_spi));
278 if (!master)
279 return -ENOMEM;
280 p = spi_master_get_devdata(master);
281 platform_set_drvdata(pdev, p);
282 p->my_master = master;
283
284 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
285
286 if (res_mem == NULL) {
287 dev_err(&pdev->dev, "found no memory resource\n");
288 err = -ENXIO;
289 goto fail;
290 }
291 if (!devm_request_mem_region(&pdev->dev, res_mem->start,
292 resource_size(res_mem), res_mem->name)) {
293 dev_err(&pdev->dev, "request_mem_region failed\n");
294 goto fail;
295 }
296 p->register_base = (u64)devm_ioremap(&pdev->dev, res_mem->start,
297 resource_size(res_mem));
298
299 /* Dynamic bus numbering */
300 master->bus_num = -1;
301 master->num_chipselect = 4;
302 master->mode_bits = SPI_CPHA |
303 SPI_CPOL |
304 SPI_CS_HIGH |
305 SPI_LSB_FIRST |
306 SPI_3WIRE;
307
308 master->setup = octeon_spi_setup;
309 master->cleanup = octeon_spi_cleanup;
310 master->prepare_transfer_hardware = octeon_spi_nop_transfer_hardware;
311 master->transfer_one_message = octeon_spi_transfer_one_message;
312 master->unprepare_transfer_hardware = octeon_spi_nop_transfer_hardware;
313
314 master->dev.of_node = pdev->dev.of_node;
315 err = spi_register_master(master);
316 if (err) {
317 dev_err(&pdev->dev, "register master failed: %d\n", err);
318 goto fail;
319 }
320
321 dev_info(&pdev->dev, "OCTEON SPI bus driver\n");
322
323 return 0;
324fail:
325 spi_master_put(master);
326 return err;
327}
328
329static int octeon_spi_remove(struct platform_device *pdev)
330{
331 struct octeon_spi *p = platform_get_drvdata(pdev);
332 u64 register_base = p->register_base;
333
334 spi_unregister_master(p->my_master);
335
336 /* Clear the CSENA* and put everything in a known state. */
337 cvmx_write_csr(register_base + OCTEON_SPI_CFG, 0);
338
339 return 0;
340}
341
342static struct of_device_id octeon_spi_match[] = {
343 { .compatible = "cavium,octeon-3010-spi", },
344 {},
345};
346MODULE_DEVICE_TABLE(of, octeon_spi_match);
347
348static struct platform_driver octeon_spi_driver = {
349 .driver = {
350 .name = "spi-octeon",
351 .owner = THIS_MODULE,
352 .of_match_table = octeon_spi_match,
353 },
354 .probe = octeon_spi_probe,
355 .remove = octeon_spi_remove,
356};
357
358module_platform_driver(octeon_spi_driver);
359
360MODULE_DESCRIPTION("Cavium, Inc. OCTEON SPI bus driver");
361MODULE_AUTHOR("David Daney");
362MODULE_LICENSE("GPL");