/*
* arch/arm/mach-u300/dummyspichip.c
*
* Copyright (C) 2007-2009 ST-Ericsson AB
* License terms: GNU General Public License (GPL) version 2
* This is a dummy loopback SPI "chip" used for testing SPI.
* Author: Linus Walleij <linus.walleij@stericsson.com>
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/sysfs.h>
#include <linux/mutex.h>
#include <linux/spi/spi.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
/*
* WARNING! Do not include this pl022-specific controller header
* for any generic driver. It is only done in this dummy chip
* because we alter the chip configuration in order to test some
* different settings on the loopback device. Normal chip configs
* shall be STATIC and not altered by the driver!
*/
#include <linux/amba/pl022.h>
struct dummy {
struct device *dev;
struct mutex lock;
};
#define DMA_TEST_SIZE 2048
/* When we cat /sys/bus/spi/devices/spi0.0/looptest this will be triggered */
static ssize_t dummy_looptest(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct spi_device *spi = to_spi_device(dev);
struct dummy *p_dummy = dev_get_drvdata(&spi->dev);
/*
* WARNING! Do not dereference the chip-specific data in any normal
* driver for a chip. It is usually STATIC and shall not be read
* or written to. Your chip driver should NOT depend on fields in this
* struct, this is just used here to alter the behaviour of the chip
* in order to perform tests.
*/
int status;
u8 txbuf[14] = {0xDE, 0xAD, 0xBE, 0xEF, 0x2B, 0xAD,
0xCA, 0xFE, 0xBA, 0xBE, 0xB1, 0x05,
0xF0, 0x0D};
u8 rxbuf[14];
u8 *bigtxbuf_virtual;
u8 *bigrxbuf_virtual;
if (mutex_lock_interruptible(&p_dummy->lock))
return -ERESTARTSYS;
bigtxbuf_virtual = kmalloc(DMA_TEST_SIZE, GFP_KERNEL);
if (bigtxbuf_virtual == NULL) {
status = -ENOMEM;
goto out;
}
bigrxbuf_virtual = kmalloc(DMA_TEST_SIZE, GFP_KERNEL);
/* Fill TXBUF with some happy pattern */
memset(bigtxbuf_virtual, 0xAA, DMA_TEST_SIZE);
/*
* Force chip to 8 bit mode
* WARNING: NEVER DO THIS IN REAL DRIVER CODE, THIS SHOULD BE STATIC!
*/
spi->bits_per_word = 8;
/* You should NOT DO THIS EITHER */
spi->master->setup(spi);
/* Now run the tests for 8bit mode */
pr_info("Simple test 1: write 0xAA byte, read back garbage byte "
"in 8bit mode\n");
status = spi_w8r8(spi, 0xAA);
if (status < 0)
pr_warning("Siple test 1: FAILURE: spi_write_then_read "
"failed with status %d\n", status);
else
pr_info("Simple test 1: SUCCESS!\n");
pr_info("Simple test 2: write 8 bytes, read back 8 bytes garbage "
"in 8bit mode (full FIFO)\n");
status = spi_write_then_read(spi, &txbuf[0], 8, &rxbuf[0], 8);
if (status < 0)
pr_warning("Simple test 2: FAILURE: spi_write_then_read() "
"failed with status %d\n", status);
else
pr_info("Simple test 2: SUCCESS!\n");
pr_info("Simple test 3: write 14 bytes, read back 14 bytes garbage "
"in 8bit mode (see if we overflow FIFO)\n");
status = spi_write_then_read(spi, &txbuf[0], 14, &rxbuf[0], 14);
if (status < 0)
pr_warning("Simple test 3: FAILURE: failed with status %d "
"(probably FIFO overrun)\n", status);
else
pr_info("Simple test 3: SUCCESS!\n");
pr_info("Simple test 4: write 8 bytes with spi_write(), read 8 "
"bytes garbage with spi_read() in 8bit mode\n");
status = spi_write(spi, &txbuf[0], 8);
if (status < 0)
pr_warning("Simple test 4 step 1: FAILURE: spi_write() "
"failed with status %d\n", status);
else
pr_info("Simple test 4 step 1: SUCCESS!\n");
status = spi_read(spi, &rxbuf[0], 8);
if (status < 0)
pr_warning("Simple test 4 step 2: FAILURE: spi_read() "
"failed with status %d\n", status);
else
pr_info("Simple test 4 step 2: SUCCESS!\n");
pr_info("Simple test 5: write 14 bytes with spi_write(), read "
"14 bytes garbage with spi_read() in 8bit mode\n");
status = spi_write(spi, &txbuf[0], 14);
if (status < 0)
pr_warning("Simple test 5 step 1: FAILURE: spi_write() "
"failed with status %d (probably FIFO overrun)\n",
status);
else
pr_info("Simple test 5 step 1: SUCCESS!\n");
status = spi_read(spi, &rxbuf[0], 14);
if (status < 0)
pr_warning("Simple test 5 step 2: FAILURE: spi_read() "
"failed with status %d (probably FIFO overrun)\n",
status);
else
pr_info("Simple test 5: SUCCESS!\n");
pr_info("Simple test 6: write %d bytes with spi_write(), "
"read %d bytes garbage with spi_read() in 8bit mode\n",
DMA_TEST_SIZE, DMA_TEST_SIZE);
status = spi_write(spi, &bigtxbuf_virtual[0], DMA_TEST_SIZE);
if (status < 0)
pr_warning("Simple test 6 step 1: FAILURE: spi_write() "
"failed with status %d (probably FIFO overrun)\n",
status);
else
pr_info("Simple test 6 step 1: SUCCESS!\n");
status = spi_read(spi, &bigrxbuf_virtual[0], DMA_TEST_SIZE);
if (status < 0)
pr_warning("Simple test 6 step 2: FAILURE: spi_read() "
"failed with status %d (probably FIFO overrun)\n",
status);
else
pr_info("Simple test 6: SUCCESS!\n");
/*
* Force chip to 16 bit mode
* WARNING: NEVER DO THIS IN REAL DRIVER CODE, THIS SHOULD BE STATIC!
*/
spi->bits_per_word = 16;
/* You should NOT DO THIS EITHER */
spi->master->setup(spi);
pr_info("Simple test 7: write 0xAA byte, read back garbage byte "
"in 16bit bus mode\n");
status = spi_w8r8(spi, 0xAA);
if (status == -EIO)
pr_info("Simple test 7: SUCCESS! (expected failure with "
"status EIO)\n");
else if (status < 0)
pr_warning("Siple test 7: FAILURE: spi_write_then_read "
"failed with status %d\n", status);
else
pr_warning("Siple test 7: FAILURE: spi_write_then_read "
"succeeded but it was expected to fail!\n");
pr_info("Simple test 8: write 8 bytes, read back 8 bytes garbage "
"in 16bit mode (full FIFO)\n");
status = spi_write_then_read(spi, &txbuf[0], 8, &rxbuf[0], 8);
if (status < 0)
pr_warning("Simple test 8: FAILURE: spi_write_then_read() "
"failed with status %d\n", status);
else
pr_info("Simple test 8: SUCCESS!\n");
pr_info("Simple test 9: write 14 bytes, read back 14 bytes garbage "
"in 16bit mode (see if we overflow FIFO)\n");
status = spi_write_then_read(spi, &txbuf[0], 14, &rxbuf[0], 14);
if (status < 0)
pr_warning("Simple test 9: FAILURE: failed with status %d "
"(probably FIFO overrun)\n", status);
else
pr_info("Simple test 9: SUCCESS!\n");
pr_info("Simple test 10: write %d bytes with spi_write(), "
"read %d bytes garbage with spi_read() in 16bit mode\n",
DMA_TEST_SIZE, DMA_TEST_SIZE);
status = spi_write(spi, &bigtxbuf_virtual[0], DMA_TEST_SIZE);
if (status < 0)
pr_warning("Simple test 10 step 1: FAILURE: spi_write() "
"failed with status %d (probably FIFO overrun)\n",
status);
else
pr_info("Simple test 10 step 1: SUCCESS!\n");
status = spi_read(spi, &bigrxbuf_virtual[0], DMA_TEST_SIZE);
if (status < 0)
pr_warning("Simple test 10 step 2: FAILURE: spi_read() "
"failed with status %d (probably FIFO overrun)\n",
status);
else
pr_info("Simple test 10: SUCCESS!\n");
status = sprintf(buf, "loop test complete\n");
kfree(bigrxbuf_virtual);
kfree(bigtxbuf_virtual);
out:
mutex_unlock(&p_dummy->lock);
return status;
}
static DEVICE_ATTR(looptest, S_IRUGO, dummy_looptest, NULL);
static int pl022_dummy_probe(struct spi_device *spi)
{
struct dummy *p_dummy;
int status;
dev_info(&spi->dev, "probing dummy SPI device\n");
p_dummy = kzalloc(sizeof *p_dummy, GFP_KERNEL);
if (!p_dummy)
return -ENOMEM;
dev_set_drvdata(&spi->dev, p_dummy);
mutex_init(&p_dummy->lock);
/* sysfs hook */
status = device_create_file(&spi->dev, &dev_attr_looptest);
if (status) {
dev_dbg(&spi->dev, "device_create_file looptest failure.\n");
goto out_dev_create_looptest_failed;
}
return 0;
out_dev_create_looptest_failed:
dev_set_drvdata(&spi->dev, NULL);
kfree(p_dummy);
return status;
}
static int pl022_dummy_remove(struct spi_device *spi)
{
struct dummy *p_dummy = dev_get_drvdata(&spi->dev);
dev_info(&spi->dev, "removing dummy SPI device\n");
device_remove_file(&spi->dev, &dev_attr_looptest);
dev_set_drvdata(&spi->dev, NULL);
kfree(p_dummy);
return 0;
}
static const struct of_device_id pl022_dummy_dt_match[] = {
{ .compatible = "arm,pl022-dummy" },
{},
};
static struct spi_driver pl022_dummy_driver = {
.driver = {
.name = "spi-dummy",
.owner = THIS_MODULE,
.of_match_table = pl022_dummy_dt_match,
},
.probe = pl022_dummy_probe,
.remove = pl022_dummy_remove,
};
module_spi_driver(pl022_dummy_driver);
MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
MODULE_DESCRIPTION("PL022 SSP/SPI DUMMY Linux driver");
MODULE_LICENSE("GPL");
