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 28struct 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 */ 36static 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_warn("Simple test 1: FAILURE: spi_write_then_read failed with status %d\n", 84 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_warn("Simple test 2: FAILURE: spi_write_then_read() failed with status %d\n", 93 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_warn("Simple test 3: FAILURE: failed with status %d (probably FIFO overrun)\n", 102 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_warn("Simple test 4 step 1: FAILURE: spi_write() failed with status %d\n", 111 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_warn("Simple test 4 step 2: FAILURE: spi_read() failed with status %d\n", 117 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_warn("Simple test 5 step 1: FAILURE: spi_write() failed with status %d (probably FIFO overrun)\n", 126 status); 127 else 128 pr_info("Simple test 5 step 1: SUCCESS!\n"); 129 status = spi_read(spi, &rxbuf[0], 14); 130 if (status < 0) 131 pr_warn("Simple test 5 step 2: FAILURE: spi_read() failed with status %d (probably FIFO overrun)\n", 132 status); 133 else 134 pr_info("Simple test 5: SUCCESS!\n"); 135 136 pr_info("Simple test 6: write %d bytes with spi_write(), " 137 "read %d bytes garbage with spi_read() in 8bit mode\n", 138 DMA_TEST_SIZE, DMA_TEST_SIZE); 139 status = spi_write(spi, &bigtxbuf_virtual[0], DMA_TEST_SIZE); 140 if (status < 0) 141 pr_warn("Simple test 6 step 1: FAILURE: spi_write() failed with status %d (probably FIFO overrun)\n", 142 status); 143 else 144 pr_info("Simple test 6 step 1: SUCCESS!\n"); 145 status = spi_read(spi, &bigrxbuf_virtual[0], DMA_TEST_SIZE); 146 if (status < 0) 147 pr_warn("Simple test 6 step 2: FAILURE: spi_read() failed with status %d (probably FIFO overrun)\n", 148 status); 149 else 150 pr_info("Simple test 6: SUCCESS!\n"); 151 152 153 /* 154 * Force chip to 16 bit mode 155 * WARNING: NEVER DO THIS IN REAL DRIVER CODE, THIS SHOULD BE STATIC! 156 */ 157 spi->bits_per_word = 16; 158 /* You should NOT DO THIS EITHER */ 159 spi->master->setup(spi); 160 161 pr_info("Simple test 7: write 0xAA byte, read back garbage byte " 162 "in 16bit bus mode\n"); 163 status = spi_w8r8(spi, 0xAA); 164 if (status == -EIO) 165 pr_info("Simple test 7: SUCCESS! (expected failure with " 166 "status EIO)\n"); 167 else if (status < 0) 168 pr_warn("Simple test 7: FAILURE: spi_write_then_read failed with status %d\n", 169 status); 170 else 171 pr_warn("Simple test 7: FAILURE: spi_write_then_read succeeded but it was expected to fail!\n"); 172 173 pr_info("Simple test 8: write 8 bytes, read back 8 bytes garbage " 174 "in 16bit mode (full FIFO)\n"); 175 status = spi_write_then_read(spi, &txbuf[0], 8, &rxbuf[0], 8); 176 if (status < 0) 177 pr_warn("Simple test 8: FAILURE: spi_write_then_read() failed with status %d\n", 178 status); 179 else 180 pr_info("Simple test 8: SUCCESS!\n"); 181 182 pr_info("Simple test 9: write 14 bytes, read back 14 bytes garbage " 183 "in 16bit mode (see if we overflow FIFO)\n"); 184 status = spi_write_then_read(spi, &txbuf[0], 14, &rxbuf[0], 14); 185 if (status < 0) 186 pr_warn("Simple test 9: FAILURE: failed with status %d (probably FIFO overrun)\n", 187 status); 188 else 189 pr_info("Simple test 9: SUCCESS!\n"); 190 191 pr_info("Simple test 10: write %d bytes with spi_write(), " 192 "read %d bytes garbage with spi_read() in 16bit mode\n", 193 DMA_TEST_SIZE, DMA_TEST_SIZE); 194 status = spi_write(spi, &bigtxbuf_virtual[0], DMA_TEST_SIZE); 195 if (status < 0) 196 pr_warn("Simple test 10 step 1: FAILURE: spi_write() failed with status %d (probably FIFO overrun)\n", 197 status); 198 else 199 pr_info("Simple test 10 step 1: SUCCESS!\n"); 200 201 status = spi_read(spi, &bigrxbuf_virtual[0], DMA_TEST_SIZE); 202 if (status < 0) 203 pr_warn("Simple test 10 step 2: FAILURE: spi_read() failed with status %d (probably FIFO overrun)\n", 204 status); 205 else 206 pr_info("Simple test 10: SUCCESS!\n"); 207 208 status = sprintf(buf, "loop test complete\n"); 209 kfree(bigrxbuf_virtual); 210 kfree(bigtxbuf_virtual); 211 out: 212 mutex_unlock(&p_dummy->lock); 213 return status; 214} 215 216static DEVICE_ATTR(looptest, S_IRUGO, dummy_looptest, NULL); 217 218static int pl022_dummy_probe(struct spi_device *spi) 219{ 220 struct dummy *p_dummy; 221 int status; 222 223 dev_info(&spi->dev, "probing dummy SPI device\n"); 224 225 p_dummy = kzalloc(sizeof *p_dummy, GFP_KERNEL); 226 if (!p_dummy) 227 return -ENOMEM; 228 229 dev_set_drvdata(&spi->dev, p_dummy); 230 mutex_init(&p_dummy->lock); 231 232 /* sysfs hook */ 233 status = device_create_file(&spi->dev, &dev_attr_looptest); 234 if (status) { 235 dev_dbg(&spi->dev, "device_create_file looptest failure.\n"); 236 goto out_dev_create_looptest_failed; 237 } 238 239 return 0; 240 241out_dev_create_looptest_failed: 242 dev_set_drvdata(&spi->dev, NULL); 243 kfree(p_dummy); 244 return status; 245} 246 247static int pl022_dummy_remove(struct spi_device *spi) 248{ 249 struct dummy *p_dummy = dev_get_drvdata(&spi->dev); 250 251 dev_info(&spi->dev, "removing dummy SPI device\n"); 252 device_remove_file(&spi->dev, &dev_attr_looptest); 253 dev_set_drvdata(&spi->dev, NULL); 254 kfree(p_dummy); 255 256 return 0; 257} 258 259static const struct of_device_id pl022_dummy_dt_match[] = { 260 { .compatible = "arm,pl022-dummy" }, 261 {}, 262}; 263 264static struct spi_driver pl022_dummy_driver = { 265 .driver = { 266 .name = "spi-dummy", 267 .owner = THIS_MODULE, 268 .of_match_table = pl022_dummy_dt_match, 269 }, 270 .probe = pl022_dummy_probe, 271 .remove = pl022_dummy_remove, 272}; 273 274module_spi_driver(pl022_dummy_driver); 275MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); 276MODULE_DESCRIPTION("PL022 SSP/SPI DUMMY Linux driver"); 277MODULE_LICENSE("GPL"); 278