Linux-libre 4.5-gnu

1 files changed, 1006 insertions, 0 deletions

diff --git a/drivers/spi/spi-loopback-test.c b/drivers/spi/spi-loopback-test.c
new file mode 100644
index 000000000..cf4bb36be
--- /dev/null
+++ b/drivers/spi/spi-loopback-test.c
@@ -0,0 +1,1006 @@
+/*
+ *  linux/drivers/spi/spi-loopback-test.c
+ *
+ *  (c) Martin Sperl <kernel@martin.sperl.org>
+ *
+ *  Loopback test driver to test several typical spi_message conditions
+ *  that a spi_master driver may encounter
+ *  this can also get used for regression testing
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/list_sort.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/printk.h>
+#include <linux/spi/spi.h>
+
+#include "spi-test.h"
+
+/* flag to only simulate transfers */
+int simulate_only;
+module_param(simulate_only, int, 0);
+MODULE_PARM_DESC(simulate_only, "if not 0 do not execute the spi message");
+
+/* dump spi messages */
+int dump_messages;
+module_param(dump_messages, int, 0);
+MODULE_PARM_DESC(dump_messages,
+		 "=1 dump the basic spi_message_structure, " \
+		 "=2 dump the spi_message_structure including data, " \
+		 "=3 dump the spi_message structure before and after execution");
+/* the device is jumpered for loopback - enabling some rx_buf tests */
+int loopback;
+module_param(loopback, int, 0);
+MODULE_PARM_DESC(loopback,
+		 "if set enable loopback mode, where the rx_buf "	\
+		 "is checked to match tx_buf after the spi_message "	\
+		 "is executed");
+
+/* run only a specific test */
+int run_only_test = -1;
+module_param(run_only_test, int, 0);
+MODULE_PARM_DESC(run_only_test,
+		 "only run the test with this number (0-based !)");
+
+/* the actual tests to execute */
+static struct spi_test spi_tests[] = {
+	{
+		.description	= "tx/rx-transfer - start of page",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_rx_align = ITERATE_ALIGN,
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(0),
+				.rx_buf = RX(0),
+			},
+		},
+	},
+	{
+		.description	= "tx/rx-transfer - crossing PAGE_SIZE",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_rx_align = ITERATE_ALIGN,
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(PAGE_SIZE - 4),
+				.rx_buf = RX(PAGE_SIZE - 4),
+			},
+		},
+	},
+	{
+		.description	= "tx-transfer - only",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(0),
+			},
+		},
+	},
+	{
+		.description	= "rx-transfer - only",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_rx_align = ITERATE_ALIGN,
+		.transfers		= {
+			{
+				.len = 1,
+				.rx_buf = RX(0),
+			},
+		},
+	},
+	{
+		.description	= "two tx-transfers - alter both",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_transfer_mask = BIT(0) | BIT(1),
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(0),
+			},
+			{
+				.len = 1,
+				/* this is why we cant use ITERATE_MAX_LEN */
+				.tx_buf = TX(SPI_TEST_MAX_SIZE_HALF),
+			},
+		},
+	},
+	{
+		.description	= "two tx-transfers - alter first",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_transfer_mask = BIT(1),
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(64),
+			},
+			{
+				.len = 1,
+				.tx_buf = TX(0),
+			},
+		},
+	},
+	{
+		.description	= "two tx-transfers - alter second",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_transfer_mask = BIT(0),
+		.transfers		= {
+			{
+				.len = 16,
+				.tx_buf = TX(0),
+			},
+			{
+				.len = 1,
+				.tx_buf = TX(64),
+			},
+		},
+	},
+	{
+		.description	= "two transfers tx then rx - alter both",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_transfer_mask = BIT(0) | BIT(1),
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(0),
+			},
+			{
+				.len = 1,
+				.rx_buf = RX(0),
+			},
+		},
+	},
+	{
+		.description	= "two transfers tx then rx - alter tx",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_transfer_mask = BIT(0),
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(0),
+			},
+			{
+				.len = 1,
+				.rx_buf = RX(0),
+			},
+		},
+	},
+	{
+		.description	= "two transfers tx then rx - alter rx",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_transfer_mask = BIT(1),
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(0),
+			},
+			{
+				.len = 1,
+				.rx_buf = RX(0),
+			},
+		},
+	},
+	{
+		.description	= "two tx+rx transfers - alter both",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_transfer_mask = BIT(0) | BIT(1),
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(0),
+				.rx_buf = RX(0),
+			},
+			{
+				.len = 1,
+				/* making sure we align without overwrite
+				 * the reason we can not use ITERATE_MAX_LEN
+				 */
+				.tx_buf = TX(SPI_TEST_MAX_SIZE_HALF),
+				.rx_buf = RX(SPI_TEST_MAX_SIZE_HALF),
+			},
+		},
+	},
+	{
+		.description	= "two tx+rx transfers - alter first",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_transfer_mask = BIT(0),
+		.transfers		= {
+			{
+				.len = 1,
+				/* making sure we align without overwrite */
+				.tx_buf = TX(1024),
+				.rx_buf = RX(1024),
+			},
+			{
+				.len = 1,
+				/* making sure we align without overwrite */
+				.tx_buf = TX(0),
+				.rx_buf = RX(0),
+			},
+		},
+	},
+	{
+		.description	= "two tx+rx transfers - alter second",
+		.fill_option	= FILL_COUNT_8,
+		.iterate_len    = { ITERATE_MAX_LEN },
+		.iterate_tx_align = ITERATE_ALIGN,
+		.iterate_transfer_mask = BIT(1),
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(0),
+				.rx_buf = RX(0),
+			},
+			{
+				.len = 1,
+				/* making sure we align without overwrite */
+				.tx_buf = TX(1024),
+				.rx_buf = RX(1024),
+			},
+		},
+	},
+
+	{ /* end of tests sequence */ }
+};
+
+static int spi_loopback_test_probe(struct spi_device *spi)
+{
+	int ret;
+
+	dev_info(&spi->dev, "Executing spi-loopback-tests\n");
+
+	ret = spi_test_run_tests(spi, spi_tests);
+
+	dev_info(&spi->dev, "Finished spi-loopback-tests with return: %i\n",
+		 ret);
+
+	return ret;
+}
+
+/* non const match table to permit to change via a module parameter */
+static struct of_device_id spi_loopback_test_of_match[] = {
+	{ .compatible	= "linux,spi-loopback-test", },
+	{ }
+};
+
+/* allow to override the compatible string via a module_parameter */
+module_param_string(compatible, spi_loopback_test_of_match[0].compatible,
+		    sizeof(spi_loopback_test_of_match[0].compatible),
+		    0000);
+
+MODULE_DEVICE_TABLE(of, spi_loopback_test_of_match);
+
+static struct spi_driver spi_loopback_test_driver = {
+	.driver = {
+		.name = "spi-loopback-test",
+		.owner = THIS_MODULE,
+		.of_match_table = spi_loopback_test_of_match,
+	},
+	.probe = spi_loopback_test_probe,
+};
+
+module_spi_driver(spi_loopback_test_driver);
+
+MODULE_AUTHOR("Martin Sperl <kernel@martin.sperl.org>");
+MODULE_DESCRIPTION("test spi_driver to check core functionality");
+MODULE_LICENSE("GPL");
+
+/*-------------------------------------------------------------------------*/
+
+/* spi_test implementation */
+
+#define RANGE_CHECK(ptr, plen, start, slen) \
+	((ptr >= start) && (ptr + plen <= start + slen))
+
+/* we allocate one page more, to allow for offsets */
+#define SPI_TEST_MAX_SIZE_PLUS (SPI_TEST_MAX_SIZE + PAGE_SIZE)
+
+static void spi_test_print_hex_dump(char *pre, const void *ptr, size_t len)
+{
+	/* limit the hex_dump */
+	if (len < 1024) {
+		print_hex_dump(KERN_INFO, pre,
+			       DUMP_PREFIX_OFFSET, 16, 1,
+			       ptr, len, 0);
+		return;
+	}
+	/* print head */
+	print_hex_dump(KERN_INFO, pre,
+		       DUMP_PREFIX_OFFSET, 16, 1,
+		       ptr, 512, 0);
+	/* print tail */
+	pr_info("%s truncated - continuing at offset %04zx\n",
+		pre, len - 512);
+	print_hex_dump(KERN_INFO, pre,
+		       DUMP_PREFIX_OFFSET, 16, 1,
+		       ptr + (len - 512), 512, 0);
+}
+
+static void spi_test_dump_message(struct spi_device *spi,
+				  struct spi_message *msg,
+				  bool dump_data)
+{
+	struct spi_transfer *xfer;
+	int i;
+	u8 b;
+
+	dev_info(&spi->dev, "  spi_msg@%pK\n", msg);
+	if (msg->status)
+		dev_info(&spi->dev, "    status:        %i\n",
+			 msg->status);
+	dev_info(&spi->dev, "    frame_length:  %i\n",
+		 msg->frame_length);
+	dev_info(&spi->dev, "    actual_length: %i\n",
+		 msg->actual_length);
+
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		dev_info(&spi->dev, "    spi_transfer@%pK\n", xfer);
+		dev_info(&spi->dev, "      len:    %i\n", xfer->len);
+		dev_info(&spi->dev, "      tx_buf: %pK\n", xfer->tx_buf);
+		if (dump_data && xfer->tx_buf)
+			spi_test_print_hex_dump("          TX: ",
+						xfer->tx_buf,
+						xfer->len);
+
+		dev_info(&spi->dev, "      rx_buf: %pK\n", xfer->rx_buf);
+		if (dump_data && xfer->rx_buf)
+			spi_test_print_hex_dump("          RX: ",
+						xfer->rx_buf,
+						xfer->len);
+		/* check for unwritten test pattern on rx_buf */
+		if (xfer->rx_buf) {
+			for (i = 0 ; i < xfer->len ; i++) {
+				b = ((u8 *)xfer->rx_buf)[xfer->len - 1 - i];
+				if (b != SPI_TEST_PATTERN_UNWRITTEN)
+					break;
+			}
+			if (i)
+				dev_info(&spi->dev,
+					 "      rx_buf filled with %02x starts at offset: %i\n",
+					 SPI_TEST_PATTERN_UNWRITTEN,
+					 xfer->len - i);
+		}
+	}
+}
+
+struct rx_ranges {
+	struct list_head list;
+	u8 *start;
+	u8 *end;
+};
+
+int rx_ranges_cmp(void *priv, struct list_head *a, struct list_head *b)
+{
+	struct rx_ranges *rx_a = list_entry(a, struct rx_ranges, list);
+	struct rx_ranges *rx_b = list_entry(b, struct rx_ranges, list);
+
+	if (rx_a->start > rx_b->start)
+		return 1;
+	if (rx_a->start < rx_b->start)
+		return -1;
+	return 0;
+}
+
+static int spi_check_rx_ranges(struct spi_device *spi,
+			       struct spi_message *msg,
+			       void *rx)
+{
+	struct spi_transfer *xfer;
+	struct rx_ranges ranges[SPI_TEST_MAX_TRANSFERS], *r;
+	int i = 0;
+	LIST_HEAD(ranges_list);
+	u8 *addr;
+	int ret = 0;
+
+	/* loop over all transfers to fill in the rx_ranges */
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		/* if there is no rx, then no check is needed */
+		if (!xfer->rx_buf)
+			continue;
+		/* fill in the rx_range */
+		if (RANGE_CHECK(xfer->rx_buf, xfer->len,
+				rx, SPI_TEST_MAX_SIZE_PLUS)) {
+			ranges[i].start = xfer->rx_buf;
+			ranges[i].end = xfer->rx_buf + xfer->len;
+			list_add(&ranges[i].list, &ranges_list);
+			i++;
+		}
+	}
+
+	/* if no ranges, then we can return and avoid the checks...*/
+	if (!i)
+		return 0;
+
+	/* sort the list */
+	list_sort(NULL, &ranges_list, rx_ranges_cmp);
+
+	/* and iterate over all the rx addresses */
+	for (addr = rx; addr < (u8 *)rx + SPI_TEST_MAX_SIZE_PLUS; addr++) {
+		/* if we are the DO not write pattern,
+		 * then continue with the loop...
+		 */
+		if (*addr == SPI_TEST_PATTERN_DO_NOT_WRITE)
+			continue;
+
+		/* check if we are inside a range */
+		list_for_each_entry(r, &ranges_list, list) {
+			/* if so then set to end... */
+			if ((addr >= r->start) && (addr < r->end))
+				addr = r->end;
+		}
+		/* second test after a (hopefull) translation */
+		if (*addr == SPI_TEST_PATTERN_DO_NOT_WRITE)
+			continue;
+
+		/* if still not found then something has modified too much */
+		/* we could list the "closest" transfer here... */
+		dev_err(&spi->dev,
+			"loopback strangeness - rx changed outside of allowed range at: %pK\n",
+			addr);
+		/* do not return, only set ret,
+		 * so that we list all addresses
+		 */
+		ret = -ERANGE;
+	}
+
+	return ret;
+}
+
+static int spi_test_check_loopback_result(struct spi_device *spi,
+					  struct spi_message *msg,
+					  void *tx, void *rx)
+{
+	struct spi_transfer *xfer;
+	u8 rxb, txb;
+	size_t i;
+	int ret;
+
+	/* checks rx_buffer pattern are valid with loopback or without */
+	ret = spi_check_rx_ranges(spi, msg, rx);
+	if (ret)
+		return ret;
+
+	/* if we run without loopback, then return now */
+	if (!loopback)
+		return 0;
+
+	/* if applicable to transfer check that rx_buf is equal to tx_buf */
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		/* if there is no rx, then no check is needed */
+		if (!xfer->rx_buf)
+			continue;
+		/* so depending on tx_buf we need to handle things */
+		if (xfer->tx_buf) {
+			for (i = 1; i < xfer->len; i++) {
+				txb = ((u8 *)xfer->tx_buf)[i];
+				rxb = ((u8 *)xfer->rx_buf)[i];
+				if (txb != rxb)
+					goto mismatch_error;
+			}
+		} else {
+			/* first byte received */
+			txb = ((u8 *)xfer->rx_buf)[0];
+			/* first byte may be 0 or xff */
+			if (!((txb == 0) || (txb == 0xff))) {
+				dev_err(&spi->dev,
+					"loopback strangeness - we expect 0x00 or 0xff, but not 0x%02x\n",
+					txb);
+				return -EINVAL;
+			}
+			/* check that all bytes are identical */
+			for (i = 1; i < xfer->len; i++) {
+				rxb = ((u8 *)xfer->rx_buf)[i];
+				if (rxb != txb)
+					goto mismatch_error;
+			}
+		}
+	}
+
+	return 0;
+
+mismatch_error:
+	dev_err(&spi->dev,
+		"loopback strangeness - transfer missmatch on byte %04zx - expected 0x%02x, but got 0x%02x\n",
+		i, txb, rxb);
+
+	return -EINVAL;
+}
+
+static int spi_test_translate(struct spi_device *spi,
+			      void **ptr, size_t len,
+			      void *tx, void *rx)
+{
+	size_t off;
+
+	/* return on null */
+	if (!*ptr)
+		return 0;
+
+	/* in the MAX_SIZE_HALF case modify the pointer */
+	if (((size_t)*ptr) & SPI_TEST_MAX_SIZE_HALF)
+		/* move the pointer to the correct range */
+		*ptr += (SPI_TEST_MAX_SIZE_PLUS / 2) -
+			SPI_TEST_MAX_SIZE_HALF;
+
+	/* RX range
+	 * - we check against MAX_SIZE_PLUS to allow for automated alignment
+	 */
+	if (RANGE_CHECK(*ptr, len,  RX(0), SPI_TEST_MAX_SIZE_PLUS)) {
+		off = *ptr - RX(0);
+		*ptr = rx + off;
+
+		return 0;
+	}
+
+	/* TX range */
+	if (RANGE_CHECK(*ptr, len,  TX(0), SPI_TEST_MAX_SIZE_PLUS)) {
+		off = *ptr - TX(0);
+		*ptr = tx + off;
+
+		return 0;
+	}
+
+	dev_err(&spi->dev,
+		"PointerRange [%pK:%pK[ not in range [%pK:%pK[ or [%pK:%pK[\n",
+		*ptr, *ptr + len,
+		RX(0), RX(SPI_TEST_MAX_SIZE),
+		TX(0), TX(SPI_TEST_MAX_SIZE));
+
+	return -EINVAL;
+}
+
+static int spi_test_fill_pattern(struct spi_device *spi,
+				 struct spi_test *test)
+{
+	struct spi_transfer *xfers = test->transfers;
+	u8 *tx_buf;
+	size_t count = 0;
+	int i, j;
+
+#ifdef __BIG_ENDIAN
+#define GET_VALUE_BYTE(value, index, bytes) \
+	(value >> (8 * (bytes - 1 - count % bytes)))
+#else
+#define GET_VALUE_BYTE(value, index, bytes) \
+	(value >> (8 * (count % bytes)))
+#endif
+
+	/* fill all transfers with the pattern requested */
+	for (i = 0; i < test->transfer_count; i++) {
+		/* fill rx_buf with SPI_TEST_PATTERN_UNWRITTEN */
+		if (xfers[i].rx_buf)
+			memset(xfers[i].rx_buf, SPI_TEST_PATTERN_UNWRITTEN,
+			       xfers[i].len);
+		/* if tx_buf is NULL then skip */
+		tx_buf = (u8 *)xfers[i].tx_buf;
+		if (!tx_buf)
+			continue;
+		/* modify all the transfers */
+		for (j = 0; j < xfers[i].len; j++, tx_buf++, count++) {
+			/* fill tx */
+			switch (test->fill_option) {
+			case FILL_MEMSET_8:
+				*tx_buf = test->fill_pattern;
+				break;
+			case FILL_MEMSET_16:
+				*tx_buf = GET_VALUE_BYTE(test->fill_pattern,
+							 count, 2);
+				break;
+			case FILL_MEMSET_24:
+				*tx_buf = GET_VALUE_BYTE(test->fill_pattern,
+							 count, 3);
+				break;
+			case FILL_MEMSET_32:
+				*tx_buf = GET_VALUE_BYTE(test->fill_pattern,
+							 count, 4);
+				break;
+			case FILL_COUNT_8:
+				*tx_buf = count;
+				break;
+			case FILL_COUNT_16:
+				*tx_buf = GET_VALUE_BYTE(count, count, 2);
+				break;
+			case FILL_COUNT_24:
+				*tx_buf = GET_VALUE_BYTE(count, count, 3);
+				break;
+			case FILL_COUNT_32:
+				*tx_buf = GET_VALUE_BYTE(count, count, 4);
+				break;
+			case FILL_TRANSFER_BYTE_8:
+				*tx_buf = j;
+				break;
+			case FILL_TRANSFER_BYTE_16:
+				*tx_buf = GET_VALUE_BYTE(j, j, 2);
+				break;
+			case FILL_TRANSFER_BYTE_24:
+				*tx_buf = GET_VALUE_BYTE(j, j, 3);
+				break;
+			case FILL_TRANSFER_BYTE_32:
+				*tx_buf = GET_VALUE_BYTE(j, j, 4);
+				break;
+			case FILL_TRANSFER_NUM:
+				*tx_buf = i;
+				break;
+			default:
+				dev_err(&spi->dev,
+					"unsupported fill_option: %i\n",
+					test->fill_option);
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int _spi_test_run_iter(struct spi_device *spi,
+			      struct spi_test *test,
+			      void *tx, void *rx)
+{
+	struct spi_message *msg = &test->msg;
+	struct spi_transfer *x;
+	int i, ret;
+
+	/* initialize message - zero-filled via static initialization */
+	spi_message_init_no_memset(msg);
+
+	/* fill rx with the DO_NOT_WRITE pattern */
+	memset(rx, SPI_TEST_PATTERN_DO_NOT_WRITE, SPI_TEST_MAX_SIZE_PLUS);
+
+	/* add the individual transfers */
+	for (i = 0; i < test->transfer_count; i++) {
+		x = &test->transfers[i];
+
+		/* patch the values of tx_buf */
+		ret = spi_test_translate(spi, (void **)&x->tx_buf, x->len,
+					 (void *)tx, rx);
+		if (ret)
+			return ret;
+
+		/* patch the values of rx_buf */
+		ret = spi_test_translate(spi, &x->rx_buf, x->len,
+					 (void *)tx, rx);
+		if (ret)
+			return ret;
+
+		/* and add it to the list */
+		spi_message_add_tail(x, msg);
+	}
+
+	/* fill in the transfer buffers with pattern */
+	ret = spi_test_fill_pattern(spi, test);
+	if (ret)
+		return ret;
+
+	/* and execute */
+	if (test->execute_msg)
+		ret = test->execute_msg(spi, test, tx, rx);
+	else
+		ret = spi_test_execute_msg(spi, test, tx, rx);
+
+	/* handle result */
+	if (ret == test->expected_return)
+		return 0;
+
+	dev_err(&spi->dev,
+		"test failed - test returned %i, but we expect %i\n",
+		ret, test->expected_return);
+
+	if (ret)
+		return ret;
+
+	/* if it is 0, as we expected something else,
+	 * then return something special
+	 */
+	return -EFAULT;
+}
+
+static int spi_test_run_iter(struct spi_device *spi,
+			     const struct spi_test *testtemplate,
+			     void *tx, void *rx,
+			     size_t len,
+			     size_t tx_off,
+			     size_t rx_off
+	)
+{
+	struct spi_test test;
+	int i, tx_count, rx_count;
+
+	/* copy the test template to test */
+	memcpy(&test, testtemplate, sizeof(test));
+
+	/* set up test->transfers to the correct count */
+	if (!test.transfer_count) {
+		for (i = 0;
+		    (i < SPI_TEST_MAX_TRANSFERS) && test.transfers[i].len;
+		    i++) {
+			test.transfer_count++;
+		}
+	}
+
+	/* if iterate_transfer_mask is not set,
+	 * then set it to first transfer only
+	 */
+	if (!(test.iterate_transfer_mask & (BIT(test.transfer_count) - 1)))
+		test.iterate_transfer_mask = 1;
+
+	/* count number of transfers with tx/rx_buf != NULL */
+	rx_count = tx_count = 0;
+	for (i = 0; i < test.transfer_count; i++) {
+		if (test.transfers[i].tx_buf)
+			tx_count++;
+		if (test.transfers[i].rx_buf)
+			rx_count++;
+	}
+
+	/* in some iteration cases warn and exit early,
+	 * as there is nothing to do, that has not been tested already...
+	 */
+	if (tx_off && (!tx_count)) {
+		dev_warn_once(&spi->dev,
+			      "%s: iterate_tx_off configured with tx_buf==NULL - ignoring\n",
+			      test.description);
+		return 0;
+	}
+	if (rx_off && (!rx_count)) {
+		dev_warn_once(&spi->dev,
+			      "%s: iterate_rx_off configured with rx_buf==NULL - ignoring\n",
+			      test.description);
+		return 0;
+	}
+
+	/* write out info */
+	if (!(len || tx_off || rx_off)) {
+		dev_info(&spi->dev, "Running test %s\n", test.description);
+	} else {
+		dev_info(&spi->dev,
+			 "  with iteration values: len = %zu, tx_off = %zu, rx_off = %zu\n",
+			 len, tx_off, rx_off);
+	}
+
+	/* update in the values from iteration values */
+	for (i = 0; i < test.transfer_count; i++) {
+		/* only when bit in transfer mask is set */
+		if (!(test.iterate_transfer_mask & BIT(i)))
+			continue;
+		if (len)
+			test.transfers[i].len = len;
+		if (test.transfers[i].tx_buf)
+			test.transfers[i].tx_buf += tx_off;
+		if (test.transfers[i].tx_buf)
+			test.transfers[i].rx_buf += rx_off;
+	}
+
+	/* and execute */
+	return _spi_test_run_iter(spi, &test, tx, rx);
+}
+
+/**
+ * spi_test_execute_msg - default implementation to run a test
+ *
+ * spi: @spi_device on which to run the @spi_message
+ * test: the test to execute, which already contains @msg
+ * tx:   the tx buffer allocated for the test sequence
+ * rx:   the rx buffer allocated for the test sequence
+ *
+ * Returns: error code of spi_sync as well as basic error checking
+ */
+int spi_test_execute_msg(struct spi_device *spi, struct spi_test *test,
+			 void *tx, void *rx)
+{
+	struct spi_message *msg = &test->msg;
+	int ret = 0;
+	int i;
+
+	/* only if we do not simulate */
+	if (!simulate_only) {
+		/* dump the complete message before and after the transfer */
+		if (dump_messages == 3)
+			spi_test_dump_message(spi, msg, true);
+
+		/* run spi message */
+		ret = spi_sync(spi, msg);
+		if (ret == -ETIMEDOUT) {
+			dev_info(&spi->dev,
+				 "spi-message timed out - reruning...\n");
+			/* rerun after a few explicit schedules */
+			for (i = 0; i < 16; i++)
+				schedule();
+			ret = spi_sync(spi, msg);
+		}
+		if (ret) {
+			dev_err(&spi->dev,
+				"Failed to execute spi_message: %i\n",
+				ret);
+			goto exit;
+		}
+
+		/* do some extra error checks */
+		if (msg->frame_length != msg->actual_length) {
+			dev_err(&spi->dev,
+				"actual length differs from expected\n");
+			ret = -EIO;
+			goto exit;
+		}
+
+		/* run rx-buffer tests */
+		ret = spi_test_check_loopback_result(spi, msg, tx, rx);
+	}
+
+	/* if requested or on error dump message (including data) */
+exit:
+	if (dump_messages || ret)
+		spi_test_dump_message(spi, msg,
+				      (dump_messages >= 2) || (ret));
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(spi_test_execute_msg);
+
+/**
+ * spi_test_run_test - run an individual spi_test
+ *                     including all the relevant iterations on:
+ *                     length and buffer alignment
+ *
+ * spi:  the spi_device to send the messages to
+ * test: the test which we need to execute
+ * tx:   the tx buffer allocated for the test sequence
+ * rx:   the rx buffer allocated for the test sequence
+ *
+ * Returns: status code of spi_sync or other failures
+ */
+
+int spi_test_run_test(struct spi_device *spi, const struct spi_test *test,
+		      void *tx, void *rx)
+{
+	int idx_len;
+	size_t len;
+	size_t tx_align, rx_align;
+	int ret;
+
+	/* test for transfer limits */
+	if (test->transfer_count >= SPI_TEST_MAX_TRANSFERS) {
+		dev_err(&spi->dev,
+			"%s: Exceeded max number of transfers with %i\n",
+			test->description, test->transfer_count);
+		return -E2BIG;
+	}
+
+	/* setting up some values in spi_message
+	 * based on some settings in spi_master
+	 * some of this can also get done in the run() method
+	 */
+
+	/* iterate over all the iterable values using macros
+	 * (to make it a bit more readable...
+	 */
+#define FOR_EACH_ITERATE(var, defaultvalue)				\
+	for (idx_##var = -1, var = defaultvalue;			\
+	     ((idx_##var < 0) ||					\
+		     (							\
+			     (idx_##var < SPI_TEST_MAX_ITERATE) &&	\
+			     (var = test->iterate_##var[idx_##var])	\
+		     )							\
+	     );								\
+	     idx_##var++)
+#define FOR_EACH_ALIGNMENT(var)						\
+	for (var = 0;							\
+	    var < (test->iterate_##var ?				\
+			(spi->master->dma_alignment ?			\
+			 spi->master->dma_alignment :			\
+			 test->iterate_##var) :				\
+			1);						\
+	    var++)
+
+	FOR_EACH_ITERATE(len, 0) {
+		FOR_EACH_ALIGNMENT(tx_align) {
+			FOR_EACH_ALIGNMENT(rx_align) {
+				/* and run the iteration */
+				ret = spi_test_run_iter(spi, test,
+							tx, rx,
+							len,
+							tx_align,
+							rx_align);
+				if (ret)
+					return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(spi_test_run_test);
+
+/**
+ * spi_test_run_tests - run an array of spi_messages tests
+ * @spi: the spi device on which to run the tests
+ * @tests: NULL-terminated array of @spi_test
+ *
+ * Returns: status errors as per @spi_test_run_test()
+ */
+
+int spi_test_run_tests(struct spi_device *spi,
+		       struct spi_test *tests)
+{
+	char *rx = NULL, *tx = NULL;
+	int ret = 0, count = 0;
+	struct spi_test *test;
+
+	/* allocate rx/tx buffers of 128kB size without devm
+	 * in the hope that is on a page boundary
+	 */
+	rx = kzalloc(SPI_TEST_MAX_SIZE_PLUS, GFP_KERNEL);
+	if (!rx) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	tx = kzalloc(SPI_TEST_MAX_SIZE_PLUS, GFP_KERNEL);
+	if (!tx) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* now run the individual tests in the table */
+	for (test = tests, count = 0; test->description[0];
+	     test++, count++) {
+		/* only run test if requested */
+		if ((run_only_test > -1) && (count != run_only_test))
+			continue;
+		/* run custom implementation */
+		if (test->run_test)
+			ret = test->run_test(spi, test, tx, rx);
+		else
+			ret = spi_test_run_test(spi, test, tx, rx);
+		if (ret)
+			goto out;
+		/* add some delays so that we can easily
+		 * detect the individual tests when using a logic analyzer
+		 * we also add scheduling to avoid potential spi_timeouts...
+		 */
+		mdelay(100);
+		schedule();
+	}
+
+out:
+	kfree(rx);
+	kfree(tx);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(spi_test_run_tests);