summaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-u300/dummyspichip.c
blob: ec0283cf9a32498617feacce6170a9a3c69c465c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
/*
 * arch/arm/mach-u300/dummyspichip.c
 *
 * Copyright (C) 2007-2009 ST-Ericsson AB
 * License terms: GNU General Public License (GPL) version 2
 * This is a dummy loopback SPI "chip" used for testing SPI.
 * Author: Linus Walleij <linus.walleij@stericsson.com>
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/sysfs.h>
#include <linux/mutex.h>
#include <linux/spi/spi.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
/*
 * WARNING! Do not include this pl022-specific controller header
 * for any generic driver. It is only done in this dummy chip
 * because we alter the chip configuration in order to test some
 * different settings on the loopback device. Normal chip configs
 * shall be STATIC and not altered by the driver!
 */
#include <linux/amba/pl022.h>

struct dummy {
	struct device *dev;
	struct mutex lock;
};

#define DMA_TEST_SIZE 2048

/* When we cat /sys/bus/spi/devices/spi0.0/looptest this will be triggered */
static ssize_t dummy_looptest(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct spi_device *spi = to_spi_device(dev);
	struct dummy *p_dummy = dev_get_drvdata(&spi->dev);

	/*
	 * WARNING! Do not dereference the chip-specific data in any normal
	 * driver for a chip. It is usually STATIC and shall not be read
	 * or written to. Your chip driver should NOT depend on fields in this
	 * struct, this is just used here to alter the behaviour of the chip
	 * in order to perform tests.
	 */
	int status;
	u8 txbuf[14] = {0xDE, 0xAD, 0xBE, 0xEF, 0x2B, 0xAD,
			0xCA, 0xFE, 0xBA, 0xBE, 0xB1, 0x05,
			0xF0, 0x0D};
	u8 rxbuf[14];
	u8 *bigtxbuf_virtual;
	u8 *bigrxbuf_virtual;

	if (mutex_lock_interruptible(&p_dummy->lock))
		return -ERESTARTSYS;

	bigtxbuf_virtual = kmalloc(DMA_TEST_SIZE, GFP_KERNEL);
	if (bigtxbuf_virtual == NULL) {
		status = -ENOMEM;
		goto out;
	}
	bigrxbuf_virtual = kmalloc(DMA_TEST_SIZE, GFP_KERNEL);

	/* Fill TXBUF with some happy pattern */
	memset(bigtxbuf_virtual, 0xAA, DMA_TEST_SIZE);

	/*
	 * Force chip to 8 bit mode
	 * WARNING: NEVER DO THIS IN REAL DRIVER CODE, THIS SHOULD BE STATIC!
	 */
	spi->bits_per_word = 8;
	/* You should NOT DO THIS EITHER */
	spi->master->setup(spi);

	/* Now run the tests for 8bit mode */
	pr_info("Simple test 1: write 0xAA byte, read back garbage byte "
		"in 8bit mode\n");
	status = spi_w8r8(spi, 0xAA);
	if (status < 0)
		pr_warning("Siple test 1: FAILURE: spi_write_then_read "
			   "failed with status %d\n", status);
	else
		pr_info("Simple test 1: SUCCESS!\n");

	pr_info("Simple test 2: write 8 bytes, read back 8 bytes garbage "
		"in 8bit mode (full FIFO)\n");
	status = spi_write_then_read(spi, &txbuf[0], 8, &rxbuf[0], 8);
	if (status < 0)
		pr_warning("Simple test 2: FAILURE: spi_write_then_read() "
			   "failed with status %d\n", status);
	else
		pr_info("Simple test 2: SUCCESS!\n");

	pr_info("Simple test 3: write 14 bytes, read back 14 bytes garbage "
		"in 8bit mode (see if we overflow FIFO)\n");
	status = spi_write_then_read(spi, &txbuf[0], 14, &rxbuf[0], 14);
	if (status < 0)
		pr_warning("Simple test 3: FAILURE: failed with status %d "
			   "(probably FIFO overrun)\n", status);
	else
		pr_info("Simple test 3: SUCCESS!\n");

	pr_info("Simple test 4: write 8 bytes with spi_write(), read 8 "
		"bytes garbage with spi_read() in 8bit mode\n");
	status = spi_write(spi, &txbuf[0], 8);
	if (status < 0)
		pr_warning("Simple test 4 step 1: FAILURE: spi_write() "
			   "failed with status %d\n", status);
	else
		pr_info("Simple test 4 step 1: SUCCESS!\n");
	status = spi_read(spi, &rxbuf[0], 8);
	if (status < 0)
		pr_warning("Simple test 4 step 2: FAILURE: spi_read() "
			   "failed with status %d\n", status);
	else
		pr_info("Simple test 4 step 2: SUCCESS!\n");

	pr_info("Simple test 5: write 14 bytes with spi_write(), read "
		"14 bytes garbage with spi_read() in 8bit mode\n");
	status = spi_write(spi, &txbuf[0], 14);
	if (status < 0)
		pr_warning("Simple test 5 step 1: FAILURE: spi_write() "
			   "failed with status %d (probably FIFO overrun)\n",
			   status);
	else
		pr_info("Simple test 5 step 1: SUCCESS!\n");
	status = spi_read(spi, &rxbuf[0], 14);
	if (status < 0)
		pr_warning("Simple test 5 step 2: FAILURE: spi_read() "
			   "failed with status %d (probably FIFO overrun)\n",
			   status);
	else
		pr_info("Simple test 5: SUCCESS!\n");

	pr_info("Simple test 6: write %d bytes with spi_write(), "
		"read %d bytes garbage with spi_read() in 8bit mode\n",
		DMA_TEST_SIZE, DMA_TEST_SIZE);
	status = spi_write(spi, &bigtxbuf_virtual[0], DMA_TEST_SIZE);
	if (status < 0)
		pr_warning("Simple test 6 step 1: FAILURE: spi_write() "
			   "failed with status %d (probably FIFO overrun)\n",
			   status);
	else
		pr_info("Simple test 6 step 1: SUCCESS!\n");
	status = spi_read(spi, &bigrxbuf_virtual[0], DMA_TEST_SIZE);
	if (status < 0)
		pr_warning("Simple test 6 step 2: FAILURE: spi_read() "
			   "failed with status %d (probably FIFO overrun)\n",
			   status);
	else
		pr_info("Simple test 6: SUCCESS!\n");


	/*
	 * Force chip to 16 bit mode
	 * WARNING: NEVER DO THIS IN REAL DRIVER CODE, THIS SHOULD BE STATIC!
	 */
	spi->bits_per_word = 16;
	/* You should NOT DO THIS EITHER */
	spi->master->setup(spi);

	pr_info("Simple test 7: write 0xAA byte, read back garbage byte "
		"in 16bit bus mode\n");
	status = spi_w8r8(spi, 0xAA);
	if (status == -EIO)
		pr_info("Simple test 7: SUCCESS! (expected failure with "
			"status EIO)\n");
	else if (status < 0)
		pr_warning("Siple test 7: FAILURE: spi_write_then_read "
			   "failed with status %d\n", status);
	else
		pr_warning("Siple test 7: FAILURE: spi_write_then_read "
			   "succeeded but it was expected to fail!\n");

	pr_info("Simple test 8: write 8 bytes, read back 8 bytes garbage "
		"in 16bit mode (full FIFO)\n");
	status = spi_write_then_read(spi, &txbuf[0], 8, &rxbuf[0], 8);
	if (status < 0)
		pr_warning("Simple test 8: FAILURE: spi_write_then_read() "
			   "failed with status %d\n", status);
	else
		pr_info("Simple test 8: SUCCESS!\n");

	pr_info("Simple test 9: write 14 bytes, read back 14 bytes garbage "
		"in 16bit mode (see if we overflow FIFO)\n");
	status = spi_write_then_read(spi, &txbuf[0], 14, &rxbuf[0], 14);
	if (status < 0)
		pr_warning("Simple test 9: FAILURE: failed with status %d "
			   "(probably FIFO overrun)\n", status);
	else
		pr_info("Simple test 9: SUCCESS!\n");

	pr_info("Simple test 10: write %d bytes with spi_write(), "
	       "read %d bytes garbage with spi_read() in 16bit mode\n",
	       DMA_TEST_SIZE, DMA_TEST_SIZE);
	status = spi_write(spi, &bigtxbuf_virtual[0], DMA_TEST_SIZE);
	if (status < 0)
		pr_warning("Simple test 10 step 1: FAILURE: spi_write() "
			   "failed with status %d (probably FIFO overrun)\n",
			   status);
	else
		pr_info("Simple test 10 step 1: SUCCESS!\n");

	status = spi_read(spi, &bigrxbuf_virtual[0], DMA_TEST_SIZE);
	if (status < 0)
		pr_warning("Simple test 10 step 2: FAILURE: spi_read() "
			   "failed with status %d (probably FIFO overrun)\n",
			   status);
	else
		pr_info("Simple test 10: SUCCESS!\n");

	status = sprintf(buf, "loop test complete\n");
	kfree(bigrxbuf_virtual);
	kfree(bigtxbuf_virtual);
 out:
	mutex_unlock(&p_dummy->lock);
	return status;
}

static DEVICE_ATTR(looptest, S_IRUGO, dummy_looptest, NULL);

static int pl022_dummy_probe(struct spi_device *spi)
{
	struct dummy *p_dummy;
	int status;

	dev_info(&spi->dev, "probing dummy SPI device\n");

	p_dummy = kzalloc(sizeof *p_dummy, GFP_KERNEL);
	if (!p_dummy)
		return -ENOMEM;

	dev_set_drvdata(&spi->dev, p_dummy);
	mutex_init(&p_dummy->lock);

	/* sysfs hook */
	status = device_create_file(&spi->dev, &dev_attr_looptest);
	if (status) {
		dev_dbg(&spi->dev, "device_create_file looptest failure.\n");
		goto out_dev_create_looptest_failed;
	}

	return 0;

out_dev_create_looptest_failed:
	dev_set_drvdata(&spi->dev, NULL);
	kfree(p_dummy);
	return status;
}

static int pl022_dummy_remove(struct spi_device *spi)
{
	struct dummy *p_dummy = dev_get_drvdata(&spi->dev);

	dev_info(&spi->dev, "removing dummy SPI device\n");
	device_remove_file(&spi->dev, &dev_attr_looptest);
	dev_set_drvdata(&spi->dev, NULL);
	kfree(p_dummy);

	return 0;
}

static const struct of_device_id pl022_dummy_dt_match[] = {
	{ .compatible = "arm,pl022-dummy" },
	{},
};

static struct spi_driver pl022_dummy_driver = {
	.driver = {
		.name	= "spi-dummy",
		.owner	= THIS_MODULE,
		.of_match_table = pl022_dummy_dt_match,
	},
	.probe	= pl022_dummy_probe,
	.remove	= pl022_dummy_remove,
};

module_spi_driver(pl022_dummy_driver);
MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
MODULE_DESCRIPTION("PL022 SSP/SPI DUMMY Linux driver");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud