/* * 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 __devinit 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 __devexit 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 struct spi_driver pl022_dummy_driver = { .driver = { .name = "spi-dummy", .owner = THIS_MODULE, }, .probe = pl022_dummy_probe, .remove = __devexit_p(pl022_dummy_remove), }; static int __init pl022_init_dummy(void) { return spi_register_driver(&pl022_dummy_driver); } static void __exit pl022_exit_dummy(void) { spi_unregister_driver(&pl022_dummy_driver); } module_init(pl022_init_dummy); module_exit(pl022_exit_dummy); MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); MODULE_DESCRIPTION("PL022 SSP/SPI DUMMY Linux driver"); MODULE_LICENSE("GPL");