/*
 *  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/ktime.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/vmalloc.h>
#include <linux/spi/spi.h>

#include "spi-test.h"

/* flag to only simulate transfers */
static 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 */
static 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 */
static 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");

static int loop_req;
module_param(loop_req, int, 0);
MODULE_PARM_DESC(loop_req,
                 "if set controller will be asked to enable test loop mode. " \
                 "If controller supported it, MISO and MOSI will be connected");

static int no_cs;
module_param(no_cs, int, 0);
MODULE_PARM_DESC(no_cs,
                 "if set Chip Select (CS) will not be used");

/* run only a specific test */
static 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 !)");

/* use vmalloc'ed buffers */
static int use_vmalloc;
module_param(use_vmalloc, int, 0644);
MODULE_PARM_DESC(use_vmalloc,
                 "use vmalloc'ed buffers instead of kmalloc'ed");

/* check rx ranges */
static int check_ranges = 1;
module_param(check_ranges, int, 0644);
MODULE_PARM_DESC(check_ranges,
                 "checks rx_buffer pattern are valid");

/* 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,
                .transfer_count = 1,
                .transfers              = {
                        {
                                .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,
                .transfer_count = 1,
                .transfers              = {
                        {
                                .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,
                .transfer_count = 1,
                .transfers              = {
                        {
                                .tx_buf = TX(0),
                        },
                },
        },
        {
                .description    = "rx-transfer - only",
                .fill_option    = FILL_COUNT_8,
                .iterate_len    = { ITERATE_MAX_LEN },
                .iterate_rx_align = ITERATE_ALIGN,
                .transfer_count = 1,
                .transfers              = {
                        {
                                .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),
                .transfer_count = 2,
                .transfers              = {
                        {
                                .tx_buf = TX(0),
                        },
                        {
                                /* 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(0),
                .transfer_count = 2,
                .transfers              = {
                        {
                                .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(1),
                .transfer_count = 2,
                .transfers              = {
                        {
                                .len = 16,
                                .tx_buf = TX(0),
                        },
                        {
                                .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),
                .transfer_count = 2,
                .transfers              = {
                        {
                                .tx_buf = TX(0),
                        },
                        {
                                .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),
                .transfer_count = 2,
                .transfers              = {
                        {
                                .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),
                .transfer_count = 2,
                .transfers              = {
                        {
                                .len = 1,
                                .tx_buf = TX(0),
                        },
                        {
                                .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),
                .transfer_count = 2,
                .transfers              = {
                        {
                                .tx_buf = TX(0),
                                .rx_buf = RX(0),
                        },
                        {
                                /* 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),
                .transfer_count = 2,
                .transfers              = {
                        {
                                /* 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),
                .transfer_count = 2,
                .transfers              = {
                        {
                                .len = 1,
                                .tx_buf = TX(0),
                                .rx_buf = RX(0),
                        },
                        {
                                /* making sure we align without overwrite */
                                .tx_buf = TX(1024),
                                .rx_buf = RX(1024),
                        },
                },
        },
        {
                .description    = "two tx+rx transfers - delay after transfer",
                .fill_option    = FILL_COUNT_8,
                .iterate_len    = { ITERATE_MAX_LEN },
                .iterate_transfer_mask = BIT(0) | BIT(1),
                .transfer_count = 2,
                .transfers              = {
                        {
                                .tx_buf = TX(0),
                                .rx_buf = RX(0),
                                .delay_usecs = 1000,
                        },
                        {
                                .tx_buf = TX(0),
                                .rx_buf = RX(0),
                                .delay_usecs = 1000,
                        },
                },
        },

        { /* end of tests sequence */ }
};

static int spi_loopback_test_probe(struct spi_device *spi)
{
        int ret;

        if (loop_req || no_cs) {
                spi->mode |= loop_req ? SPI_LOOP : 0;
                spi->mode |= no_cs ? SPI_NO_CS : 0;
                ret = spi_setup(spi);
                if (ret) {
                        dev_err(&spi->dev, "SPI setup with SPI_LOOP or SPI_NO_CS failed (%d)\n",
                                ret);
                        return 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;
};

static 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_elapsed_time(struct spi_device *spi,
                                       struct spi_test *test)
{
        int i;
        unsigned long long estimated_time = 0;
        unsigned long long delay_usecs = 0;

        for (i = 0; i < test->transfer_count; i++) {
                struct spi_transfer *xfer = test->transfers + i;
                unsigned long long nbits = (unsigned long long)BITS_PER_BYTE *
                                           xfer->len;

                delay_usecs += xfer->delay_usecs;
                if (!xfer->speed_hz)
                        continue;
                estimated_time += div_u64(nbits * NSEC_PER_SEC, xfer->speed_hz);
        }

        estimated_time += delay_usecs * NSEC_PER_USEC;
        if (test->elapsed_time < estimated_time) {
                dev_err(&spi->dev,
                        "elapsed time %lld ns is shorter than minimum estimated time %lld ns\n",
                        test->elapsed_time, estimated_time);

                return -EINVAL;
        }

        return 0;
}

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 */
        if (check_ranges) {
                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->len || !xfer->rx_buf)
                        continue;
                /* so depending on tx_buf we need to handle things */
                if (xfer->tx_buf) {
                        for (i = 0; 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 mismatch 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));

        /* 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;
                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) {
                ktime_t start;

                /* dump the complete message before and after the transfer */
                if (dump_messages == 3)
                        spi_test_dump_message(spi, msg, true);

                start = ktime_get();
                /* run spi message */
                ret = spi_sync(spi, msg);
                test->elapsed_time = ktime_to_ns(ktime_sub(ktime_get(), start));
                if (ret == -ETIMEDOUT) {
                        dev_info(&spi->dev,
                                 "spi-message timed out - rerunning...\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 (ret)
                        goto exit;

                ret = spi_test_check_elapsed_time(spi, test);
        }

        /* 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_ALIGNMENT(var)                                         \
        for (var = 0;                                                   \
            var < (test->iterate_##var ?                                \
                        (spi->master->dma_alignment ?                   \
                         spi->master->dma_alignment :                   \
                         test->iterate_##var) :                         \

                        1);                                             \
            var++)

        for (idx_len = 0; idx_len < SPI_TEST_MAX_ITERATE &&
             (len = test->iterate_len[idx_len]) != -1; idx_len++) {
                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
         */
        if (use_vmalloc)
                rx = vmalloc(SPI_TEST_MAX_SIZE_PLUS);
        else
                rx = kzalloc(SPI_TEST_MAX_SIZE_PLUS, GFP_KERNEL);
        if (!rx)
                return -ENOMEM;


        if (use_vmalloc)
                tx = vmalloc(SPI_TEST_MAX_SIZE_PLUS);
        else
                tx = kzalloc(SPI_TEST_MAX_SIZE_PLUS, GFP_KERNEL);
        if (!tx) {
                ret = -ENOMEM;
                goto err_tx;
        }

        /* 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:
        kvfree(tx);
err_tx:
        kvfree(rx);
        return ret;
}
EXPORT_SYMBOL_GPL(spi_test_run_tests);