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 struct pl022_config_chip *chip_info = spi->controller_data; 50 int status; 51 u8 txbuf[14] = {0xDE, 0xAD, 0xBE, 0xEF, 0x2B, 0xAD, 52 0xCA, 0xFE, 0xBA, 0xBE, 0xB1, 0x05, 53 0xF0, 0x0D}; 54 u8 rxbuf[14]; 55 u8 *bigtxbuf_virtual; 56 u8 *bigrxbuf_virtual; 57 58 if (mutex_lock_interruptible(&p_dummy->lock)) 59 return -ERESTARTSYS; 60 61 bigtxbuf_virtual = kmalloc(DMA_TEST_SIZE, GFP_KERNEL); 62 if (bigtxbuf_virtual == NULL) { 63 status = -ENOMEM; 64 goto out; 65 } 66 bigrxbuf_virtual = kmalloc(DMA_TEST_SIZE, GFP_KERNEL); 67 68 /* Fill TXBUF with some happy pattern */ 69 memset(bigtxbuf_virtual, 0xAA, DMA_TEST_SIZE); 70 71 /* 72 * Force chip to 8 bit mode 73 * WARNING: NEVER DO THIS IN REAL DRIVER CODE, THIS SHOULD BE STATIC! 74 */ 75 chip_info->data_size = SSP_DATA_BITS_8; 76 /* You should NOT DO THIS EITHER */ 77 spi->master->setup(spi); 78 79 /* Now run the tests for 8bit mode */ 80 pr_info("Simple test 1: write 0xAA byte, read back garbage byte " 81 "in 8bit mode\n"); 82 status = spi_w8r8(spi, 0xAA); 83 if (status < 0) 84 pr_warning("Siple test 1: FAILURE: spi_write_then_read " 85 "failed with status %d\n", status); 86 else 87 pr_info("Simple test 1: SUCCESS!\n"); 88 89 pr_info("Simple test 2: write 8 bytes, read back 8 bytes garbage " 90 "in 8bit mode (full FIFO)\n"); 91 status = spi_write_then_read(spi, &txbuf[0], 8, &rxbuf[0], 8); 92 if (status < 0) 93 pr_warning("Simple test 2: FAILURE: spi_write_then_read() " 94 "failed with status %d\n", status); 95 else 96 pr_info("Simple test 2: SUCCESS!\n"); 97 98 pr_info("Simple test 3: write 14 bytes, read back 14 bytes garbage " 99 "in 8bit mode (see if we overflow FIFO)\n"); 100 status = spi_write_then_read(spi, &txbuf[0], 14, &rxbuf[0], 14); 101 if (status < 0) 102 pr_warning("Simple test 3: FAILURE: failed with status %d " 103 "(probably FIFO overrun)\n", status); 104 else 105 pr_info("Simple test 3: SUCCESS!\n"); 106 107 pr_info("Simple test 4: write 8 bytes with spi_write(), read 8 " 108 "bytes garbage with spi_read() in 8bit mode\n"); 109 status = spi_write(spi, &txbuf[0], 8); 110 if (status < 0) 111 pr_warning("Simple test 4 step 1: FAILURE: spi_write() " 112 "failed with status %d\n", status); 113 else 114 pr_info("Simple test 4 step 1: SUCCESS!\n"); 115 status = spi_read(spi, &rxbuf[0], 8); 116 if (status < 0) 117 pr_warning("Simple test 4 step 2: FAILURE: spi_read() " 118 "failed with status %d\n", status); 119 else 120 pr_info("Simple test 4 step 2: SUCCESS!\n"); 121 122 pr_info("Simple test 5: write 14 bytes with spi_write(), read " 123 "14 bytes garbage with spi_read() in 8bit mode\n"); 124 status = spi_write(spi, &txbuf[0], 14); 125 if (status < 0) 126 pr_warning("Simple test 5 step 1: FAILURE: spi_write() " 127 "failed with status %d (probably FIFO overrun)\n", 128 status); 129 else 130 pr_info("Simple test 5 step 1: SUCCESS!\n"); 131 status = spi_read(spi, &rxbuf[0], 14); 132 if (status < 0) 133 pr_warning("Simple test 5 step 2: FAILURE: spi_read() " 134 "failed with status %d (probably FIFO overrun)\n", 135 status); 136 else 137 pr_info("Simple test 5: SUCCESS!\n"); 138 139 pr_info("Simple test 6: write %d bytes with spi_write(), " 140 "read %d bytes garbage with spi_read() in 8bit mode\n", 141 DMA_TEST_SIZE, DMA_TEST_SIZE); 142 status = spi_write(spi, &bigtxbuf_virtual[0], DMA_TEST_SIZE); 143 if (status < 0) 144 pr_warning("Simple test 6 step 1: FAILURE: spi_write() " 145 "failed with status %d (probably FIFO overrun)\n", 146 status); 147 else 148 pr_info("Simple test 6 step 1: SUCCESS!\n"); 149 status = spi_read(spi, &bigrxbuf_virtual[0], DMA_TEST_SIZE); 150 if (status < 0) 151 pr_warning("Simple test 6 step 2: FAILURE: spi_read() " 152 "failed with status %d (probably FIFO overrun)\n", 153 status); 154 else 155 pr_info("Simple test 6: SUCCESS!\n"); 156 157 158 /* 159 * Force chip to 16 bit mode 160 * WARNING: NEVER DO THIS IN REAL DRIVER CODE, THIS SHOULD BE STATIC! 161 */ 162 chip_info->data_size = SSP_DATA_BITS_16; 163 /* You should NOT DO THIS EITHER */ 164 spi->master->setup(spi); 165 166 pr_info("Simple test 7: write 0xAA byte, read back garbage byte " 167 "in 16bit bus mode\n"); 168 status = spi_w8r8(spi, 0xAA); 169 if (status == -EIO) 170 pr_info("Simple test 7: SUCCESS! (expected failure with " 171 "status EIO)\n"); 172 else if (status < 0) 173 pr_warning("Siple test 7: FAILURE: spi_write_then_read " 174 "failed with status %d\n", status); 175 else 176 pr_warning("Siple test 7: FAILURE: spi_write_then_read " 177 "succeeded but it was expected to fail!\n"); 178 179 pr_info("Simple test 8: write 8 bytes, read back 8 bytes garbage " 180 "in 16bit mode (full FIFO)\n"); 181 status = spi_write_then_read(spi, &txbuf[0], 8, &rxbuf[0], 8); 182 if (status < 0) 183 pr_warning("Simple test 8: FAILURE: spi_write_then_read() " 184 "failed with status %d\n", status); 185 else 186 pr_info("Simple test 8: SUCCESS!\n"); 187 188 pr_info("Simple test 9: write 14 bytes, read back 14 bytes garbage " 189 "in 16bit mode (see if we overflow FIFO)\n"); 190 status = spi_write_then_read(spi, &txbuf[0], 14, &rxbuf[0], 14); 191 if (status < 0) 192 pr_warning("Simple test 9: FAILURE: failed with status %d " 193 "(probably FIFO overrun)\n", status); 194 else 195 pr_info("Simple test 9: SUCCESS!\n"); 196 197 pr_info("Simple test 10: write %d bytes with spi_write(), " 198 "read %d bytes garbage with spi_read() in 16bit mode\n", 199 DMA_TEST_SIZE, DMA_TEST_SIZE); 200 status = spi_write(spi, &bigtxbuf_virtual[0], DMA_TEST_SIZE); 201 if (status < 0) 202 pr_warning("Simple test 10 step 1: FAILURE: spi_write() " 203 "failed with status %d (probably FIFO overrun)\n", 204 status); 205 else 206 pr_info("Simple test 10 step 1: SUCCESS!\n"); 207 208 status = spi_read(spi, &bigrxbuf_virtual[0], DMA_TEST_SIZE); 209 if (status < 0) 210 pr_warning("Simple test 10 step 2: FAILURE: spi_read() " 211 "failed with status %d (probably FIFO overrun)\n", 212 status); 213 else 214 pr_info("Simple test 10: SUCCESS!\n"); 215 216 status = sprintf(buf, "loop test complete\n"); 217 kfree(bigrxbuf_virtual); 218 kfree(bigtxbuf_virtual); 219 out: 220 mutex_unlock(&p_dummy->lock); 221 return status; 222} 223 224static DEVICE_ATTR(looptest, S_IRUGO, dummy_looptest, NULL); 225 226static int __devinit pl022_dummy_probe(struct spi_device *spi) 227{ 228 struct dummy *p_dummy; 229 int status; 230 231 dev_info(&spi->dev, "probing dummy SPI device\n"); 232 233 p_dummy = kzalloc(sizeof *p_dummy, GFP_KERNEL); 234 if (!p_dummy) 235 return -ENOMEM; 236 237 dev_set_drvdata(&spi->dev, p_dummy); 238 mutex_init(&p_dummy->lock); 239 240 /* sysfs hook */ 241 status = device_create_file(&spi->dev, &dev_attr_looptest); 242 if (status) { 243 dev_dbg(&spi->dev, "device_create_file looptest failure.\n"); 244 goto out_dev_create_looptest_failed; 245 } 246 247 return 0; 248 249out_dev_create_looptest_failed: 250 dev_set_drvdata(&spi->dev, NULL); 251 kfree(p_dummy); 252 return status; 253} 254 255static int __devexit pl022_dummy_remove(struct spi_device *spi) 256{ 257 struct dummy *p_dummy = dev_get_drvdata(&spi->dev); 258 259 dev_info(&spi->dev, "removing dummy SPI device\n"); 260 device_remove_file(&spi->dev, &dev_attr_looptest); 261 dev_set_drvdata(&spi->dev, NULL); 262 kfree(p_dummy); 263 264 return 0; 265} 266 267static struct spi_driver pl022_dummy_driver = { 268 .driver = { 269 .name = "spi-dummy", 270 .owner = THIS_MODULE, 271 }, 272 .probe = pl022_dummy_probe, 273 .remove = __devexit_p(pl022_dummy_remove), 274}; 275 276static int __init pl022_init_dummy(void) 277{ 278 return spi_register_driver(&pl022_dummy_driver); 279} 280 281static void __exit pl022_exit_dummy(void) 282{ 283 spi_unregister_driver(&pl022_dummy_driver); 284} 285 286module_init(pl022_init_dummy); 287module_exit(pl022_exit_dummy); 288 289MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); 290MODULE_DESCRIPTION("PL022 SSP/SPI DUMMY Linux driver"); 291MODULE_LICENSE("GPL"); 292