1 /*
2 * arch/arm/mach-u300/dummyspichip.c
3 *
4 * Copyright (C) 2007-2009 ST-Ericsson AB
5 * License terms: GNU General Public License (GPL) version 2
6 * This is a dummy loopback SPI "chip" used for testing SPI.
7 * Author: Linus Walleij <linus.walleij@stericsson.com>
8 */
9 #include <linux/init.h>
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/device.h>
13 #include <linux/err.h>
14 #include <linux/sysfs.h>
15 #include <linux/mutex.h>
16 #include <linux/spi/spi.h>
17 #include <linux/dma-mapping.h>
18 #include <linux/slab.h>
19 /*
20 * WARNING! Do not include this pl022-specific controller header
21 * for any generic driver. It is only done in this dummy chip
22 * because we alter the chip configuration in order to test some
23 * different settings on the loopback device. Normal chip configs
24 * shall be STATIC and not altered by the driver!
25 */
26 #include <linux/amba/pl022.h>
27
28 struct dummy {
29 struct device *dev;
30 struct mutex lock;
31 };
32
33 #define DMA_TEST_SIZE 2048
34
35 /* When we cat /sys/bus/spi/devices/spi0.0/looptest this will be triggered */
36 static ssize_t dummy_looptest(struct device *dev,
37 struct device_attribute *attr, char *buf)
38 {
39 struct spi_device *spi = to_spi_device(dev);
40 struct dummy *p_dummy = dev_get_drvdata(&spi->dev);
41
42 /*
43 * WARNING! Do not dereference the chip-specific data in any normal
44 * driver for a chip. It is usually STATIC and shall not be read
45 * or written to. Your chip driver should NOT depend on fields in this
46 * struct, this is just used here to alter the behaviour of the chip
47 * in order to perform tests.
48 */
49 int status;
50 u8 txbuf[14] = {0xDE, 0xAD, 0xBE, 0xEF, 0x2B, 0xAD,
51 0xCA, 0xFE, 0xBA, 0xBE, 0xB1, 0x05,
52 0xF0, 0x0D};
53 u8 rxbuf[14];
54 u8 *bigtxbuf_virtual;
55 u8 *bigrxbuf_virtual;
56
57 if (mutex_lock_interruptible(&p_dummy->lock))
58 return -ERESTARTSYS;
59
60 bigtxbuf_virtual = kmalloc(DMA_TEST_SIZE, GFP_KERNEL);
61 if (bigtxbuf_virtual == NULL) {
62 status = -ENOMEM;
63 goto out;
64 }
65 bigrxbuf_virtual = kmalloc(DMA_TEST_SIZE, GFP_KERNEL);
66
67 /* Fill TXBUF with some happy pattern */
68 memset(bigtxbuf_virtual, 0xAA, DMA_TEST_SIZE);
69
70 /*
71 * Force chip to 8 bit mode
72 * WARNING: NEVER DO THIS IN REAL DRIVER CODE, THIS SHOULD BE STATIC!
73 */
74 spi->bits_per_word = 8;
75 /* You should NOT DO THIS EITHER */
76 spi->master->setup(spi);
77
78 /* Now run the tests for 8bit mode */
79 pr_info("Simple test 1: write 0xAA byte, read back garbage byte "
80 "in 8bit mode\n");
81 status = spi_w8r8(spi, 0xAA);
82 if (status < 0)
83 pr_warning("Siple test 1: FAILURE: spi_write_then_read "
84 "failed with status %d\n", status);
85 else
86 pr_info("Simple test 1: SUCCESS!\n");
87
88 pr_info("Simple test 2: write 8 bytes, read back 8 bytes garbage "
89 "in 8bit mode (full FIFO)\n");
90 status = spi_write_then_read(spi, &txbuf[0], 8, &rxbuf[0], 8);
91 if (status < 0)
92 pr_warning("Simple test 2: FAILURE: spi_write_then_read() "
93 "failed with status %d\n", status);
94 else
95 pr_info("Simple test 2: SUCCESS!\n");
96
97 pr_info("Simple test 3: write 14 bytes, read back 14 bytes garbage "
98 "in 8bit mode (see if we overflow FIFO)\n");
99 status = spi_write_then_read(spi, &txbuf[0], 14, &rxbuf[0], 14);
100 if (status < 0)
101 pr_warning("Simple test 3: FAILURE: failed with status %d "
102 "(probably FIFO overrun)\n", status);
103 else
104 pr_info("Simple test 3: SUCCESS!\n");
105
106 pr_info("Simple test 4: write 8 bytes with spi_write(), read 8 "
107 "bytes garbage with spi_read() in 8bit mode\n");
108 status = spi_write(spi, &txbuf[0], 8);
109 if (status < 0)
110 pr_warning("Simple test 4 step 1: FAILURE: spi_write() "
111 "failed with status %d\n", status);
112 else
113 pr_info("Simple test 4 step 1: SUCCESS!\n");
114 status = spi_read(spi, &rxbuf[0], 8);
115 if (status < 0)
116 pr_warning("Simple test 4 step 2: FAILURE: spi_read() "
117 "failed with status %d\n", status);
118 else
119 pr_info("Simple test 4 step 2: SUCCESS!\n");
120
121 pr_info("Simple test 5: write 14 bytes with spi_write(), read "
122 "14 bytes garbage with spi_read() in 8bit mode\n");
123 status = spi_write(spi, &txbuf[0], 14);
124 if (status < 0)
125 pr_warning("Simple test 5 step 1: FAILURE: spi_write() "
126 "failed with status %d (probably FIFO overrun)\n",
127 status);
128 else
129 pr_info("Simple test 5 step 1: SUCCESS!\n");
130 status = spi_read(spi, &rxbuf[0], 14);
131 if (status < 0)
132 pr_warning("Simple test 5 step 2: FAILURE: spi_read() "
133 "failed with status %d (probably FIFO overrun)\n",
134 status);
135 else
136 pr_info("Simple test 5: SUCCESS!\n");
137
138 pr_info("Simple test 6: write %d bytes with spi_write(), "
139 "read %d bytes garbage with spi_read() in 8bit mode\n",
140 DMA_TEST_SIZE, DMA_TEST_SIZE);
141 status = spi_write(spi, &bigtxbuf_virtual[0], DMA_TEST_SIZE);
142 if (status < 0)
143 pr_warning("Simple test 6 step 1: FAILURE: spi_write() "
144 "failed with status %d (probably FIFO overrun)\n",
145 status);
146 else
147 pr_info("Simple test 6 step 1: SUCCESS!\n");
148 status = spi_read(spi, &bigrxbuf_virtual[0], DMA_TEST_SIZE);
149 if (status < 0)
150 pr_warning("Simple test 6 step 2: FAILURE: spi_read() "
151 "failed with status %d (probably FIFO overrun)\n",
152 status);
153 else
154 pr_info("Simple test 6: SUCCESS!\n");
155
156
157 /*
158 * Force chip to 16 bit mode
159 * WARNING: NEVER DO THIS IN REAL DRIVER CODE, THIS SHOULD BE STATIC!
160 */
161 spi->bits_per_word = 16;
162 /* You should NOT DO THIS EITHER */
163 spi->master->setup(spi);
164
165 pr_info("Simple test 7: write 0xAA byte, read back garbage byte "
166 "in 16bit bus mode\n");
167 status = spi_w8r8(spi, 0xAA);
168 if (status == -EIO)
169 pr_info("Simple test 7: SUCCESS! (expected failure with "
170 "status EIO)\n");
171 else if (status < 0)
172 pr_warning("Siple test 7: FAILURE: spi_write_then_read "
173 "failed with status %d\n", status);
174 else
175 pr_warning("Siple test 7: FAILURE: spi_write_then_read "
176 "succeeded but it was expected to fail!\n");
177
178 pr_info("Simple test 8: write 8 bytes, read back 8 bytes garbage "
179 "in 16bit mode (full FIFO)\n");
180 status = spi_write_then_read(spi, &txbuf[0], 8, &rxbuf[0], 8);
181 if (status < 0)
182 pr_warning("Simple test 8: FAILURE: spi_write_then_read() "
183 "failed with status %d\n", status);
184 else
185 pr_info("Simple test 8: SUCCESS!\n");
186
187 pr_info("Simple test 9: write 14 bytes, read back 14 bytes garbage "
188 "in 16bit mode (see if we overflow FIFO)\n");
189 status = spi_write_then_read(spi, &txbuf[0], 14, &rxbuf[0], 14);
190 if (status < 0)
191 pr_warning("Simple test 9: FAILURE: failed with status %d "
192 "(probably FIFO overrun)\n", status);
193 else
194 pr_info("Simple test 9: SUCCESS!\n");
195
196 pr_info("Simple test 10: write %d bytes with spi_write(), "
197 "read %d bytes garbage with spi_read() in 16bit mode\n",
198 DMA_TEST_SIZE, DMA_TEST_SIZE);
199 status = spi_write(spi, &bigtxbuf_virtual[0], DMA_TEST_SIZE);
200 if (status < 0)
201 pr_warning("Simple test 10 step 1: FAILURE: spi_write() "
202 "failed with status %d (probably FIFO overrun)\n",
203 status);
204 else
205 pr_info("Simple test 10 step 1: SUCCESS!\n");
206
207 status = spi_read(spi, &bigrxbuf_virtual[0], DMA_TEST_SIZE);
208 if (status < 0)
209 pr_warning("Simple test 10 step 2: FAILURE: spi_read() "
210 "failed with status %d (probably FIFO overrun)\n",
211 status);
212 else
213 pr_info("Simple test 10: SUCCESS!\n");
214
215 status = sprintf(buf, "loop test complete\n");
216 kfree(bigrxbuf_virtual);
217 kfree(bigtxbuf_virtual);
218 out:
219 mutex_unlock(&p_dummy->lock);
220 return status;
221 }
222
223 static DEVICE_ATTR(looptest, S_IRUGO, dummy_looptest, NULL);
224
225 static int pl022_dummy_probe(struct spi_device *spi)
226 {
227 struct dummy *p_dummy;
228 int status;
229
230 dev_info(&spi->dev, "probing dummy SPI device\n");
231
232 p_dummy = kzalloc(sizeof *p_dummy, GFP_KERNEL);
233 if (!p_dummy)
234 return -ENOMEM;
235
236 dev_set_drvdata(&spi->dev, p_dummy);
237 mutex_init(&p_dummy->lock);
238
239 /* sysfs hook */
240 status = device_create_file(&spi->dev, &dev_attr_looptest);
241 if (status) {
242 dev_dbg(&spi->dev, "device_create_file looptest failure.\n");
243 goto out_dev_create_looptest_failed;
244 }
245
246 return 0;
247
248 out_dev_create_looptest_failed:
249 dev_set_drvdata(&spi->dev, NULL);
250 kfree(p_dummy);
251 return status;
252 }
253
254 static int pl022_dummy_remove(struct spi_device *spi)
255 {
256 struct dummy *p_dummy = dev_get_drvdata(&spi->dev);
257
258 dev_info(&spi->dev, "removing dummy SPI device\n");
259 device_remove_file(&spi->dev, &dev_attr_looptest);
260 dev_set_drvdata(&spi->dev, NULL);
261 kfree(p_dummy);
262
263 return 0;
264 }
265
266 static const struct of_device_id pl022_dummy_dt_match[] = {
267 { .compatible = "arm,pl022-dummy" },
268 {},
269 };
270
271 static struct spi_driver pl022_dummy_driver = {
272 .driver = {
273 .name = "spi-dummy",
274 .owner = THIS_MODULE,
275 .of_match_table = pl022_dummy_dt_match,
276 },
277 .probe = pl022_dummy_probe,
278 .remove = pl022_dummy_remove,
279 };
280
281 module_spi_driver(pl022_dummy_driver);
282 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
283 MODULE_DESCRIPTION("PL022 SSP/SPI DUMMY Linux driver");
284 MODULE_LICENSE("GPL");
285
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