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         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
 224 static DEVICE_ATTR(looptest, S_IRUGO, dummy_looptest, NULL);
 225
 226 static 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
 249 out_dev_create_looptest_failed:
 250         dev_set_drvdata(&spi->dev, NULL);
 251         kfree(p_dummy);
 252         return status;
 253 }
 254
 255 static 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
 267 static 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
 276 static int __init pl022_init_dummy(void)
 277 {
 278         return spi_register_driver(&pl022_dummy_driver);
 279 }
 280
 281 static void __exit pl022_exit_dummy(void)
 282 {
 283         spi_unregister_driver(&pl022_dummy_driver);
 284 }
 285
 286 module_init(pl022_init_dummy);
 287 module_exit(pl022_exit_dummy);
 288
 289 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
 290 MODULE_DESCRIPTION("PL022 SSP/SPI DUMMY Linux driver");
 291 MODULE_LICENSE("GPL");