arch/arm/mach-u300/dummyspichip.c

   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 struct spi_driver pl022_dummy_driver = {
 267         .driver = {
 268                 .name   = "spi-dummy",
 269                 .owner  = THIS_MODULE,
 270         },
 271         .probe  = pl022_dummy_probe,
 272         .remove = pl022_dummy_remove,
 273 };
 274
 275 static int __init pl022_init_dummy(void)
 276 {
 277         return spi_register_driver(&pl022_dummy_driver);
 278 }
 279
 280 static void __exit pl022_exit_dummy(void)
 281 {
 282         spi_unregister_driver(&pl022_dummy_driver);
 283 }
 284
 285 module_init(pl022_init_dummy);
 286 module_exit(pl022_exit_dummy);
 287
 288 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
 289 MODULE_DESCRIPTION("PL022 SSP/SPI DUMMY Linux driver");
 290 MODULE_LICENSE("GPL");