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_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
 216 static DEVICE_ATTR(looptest, S_IRUGO, dummy_looptest, NULL);
 217
 218 static 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
 241 out_dev_create_looptest_failed:
 242         dev_set_drvdata(&spi->dev, NULL);
 243         kfree(p_dummy);
 244         return status;
 245 }
 246
 247 static 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
 259 static const struct of_device_id pl022_dummy_dt_match[] = {
 260         { .compatible = "arm,pl022-dummy" },
 261         {},
 262 };
 263
 264 static struct spi_driver pl022_dummy_driver = {
 265         .driver = {
 266                 .name   = "spi-dummy",
 267                 .of_match_table = pl022_dummy_dt_match,
 268         },
 269         .probe  = pl022_dummy_probe,
 270         .remove = pl022_dummy_remove,
 271 };
 272
 273 module_spi_driver(pl022_dummy_driver);
 274 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
 275 MODULE_DESCRIPTION("PL022 SSP/SPI DUMMY Linux driver");
 276 MODULE_LICENSE("GPL");