spi: loopback-test: add ability to test zero-length transfer

The spi-loopback-test module currently cannot test the spi_message
including a zero-length transfer.  Because the zero-length transfer is
treated as a special value in several meanings.

1. The number of spi_transfer to execute in one test case is described
by spi_test.transfer_count.  It is normally computed by counting number
of transfers with len > 0 in spi_test.transfers array.

This change stops the detection for the number of spi_transfer.  Each
spi_test.transfer_count needs to be filled by hand now.

2. The spi_test.iterate_len is a list of transfer length to iterate on.
This list is terminated by zero, so zero-length transfer cannot be
included.

This changes the terminal value from 0 to -1.

3. The length for the spi_transfer masked by spi_test.iterate_transfer_mask
is iterated.  Before starting the iteration, the default value which
is statically initialized is applied.  In order to specify the default
value, zero-length is reserved.

Currently, the default values are always '1'.  So this removes this
trick and add '1' to iterate_len list.

By applying all these changes, the spi-loopback-test can execute spi
messages with zero-length transfer.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

2 files changed, 26 insertions, 48 deletions

diff --git a/drivers/spi/spi-loopback-test.c b/drivers/spi/spi-loopback-test.c
index 85c0c4e391d9..6df6dddc2890 100644
--- a/drivers/spi/spi-loopback-test.c
+++ b/drivers/spi/spi-loopback-test.c
@@ -63,9 +63,9 @@ static struct spi_test spi_tests[] = {
                 .iterate_len    = { ITERATE_MAX_LEN },
                 .iterate_tx_align = ITERATE_ALIGN,
                 .iterate_rx_align = ITERATE_ALIGN,
+                .transfer_count = 1,
                 .transfers              = {
                         {
-                                .len = 1,
                                 .tx_buf = TX(0),
                                 .rx_buf = RX(0),
                         },
@@ -77,9 +77,9 @@ static struct spi_test spi_tests[] = {
                 .iterate_len    = { ITERATE_MAX_LEN },
                 .iterate_tx_align = ITERATE_ALIGN,
                 .iterate_rx_align = ITERATE_ALIGN,
+                .transfer_count = 1,
                 .transfers              = {
                         {
-                                .len = 1,
                                 .tx_buf = TX(PAGE_SIZE - 4),
                                 .rx_buf = RX(PAGE_SIZE - 4),
                         },
@@ -90,9 +90,9 @@ static struct spi_test spi_tests[] = {
                 .fill_option    = FILL_COUNT_8,
                 .iterate_len    = { ITERATE_MAX_LEN },
                 .iterate_tx_align = ITERATE_ALIGN,
+                .transfer_count = 1,
                 .transfers              = {
                         {
-                                .len = 1,
                                 .tx_buf = TX(0),
                         },
                 },
@@ -102,9 +102,9 @@ static struct spi_test spi_tests[] = {
                 .fill_option    = FILL_COUNT_8,
                 .iterate_len    = { ITERATE_MAX_LEN },
                 .iterate_rx_align = ITERATE_ALIGN,
+                .transfer_count = 1,
                 .transfers              = {
                         {
-                                .len = 1,
                                 .rx_buf = RX(0),
                         },
                 },
@@ -115,13 +115,12 @@ static struct spi_test spi_tests[] = {
                 .iterate_len    = { ITERATE_LEN },
                 .iterate_tx_align = ITERATE_ALIGN,
                 .iterate_transfer_mask = BIT(0) | BIT(1),
+                .transfer_count = 2,
                 .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),
                         },
@@ -133,9 +132,9 @@ static struct spi_test spi_tests[] = {
                 .iterate_len    = { ITERATE_MAX_LEN },
                 .iterate_tx_align = ITERATE_ALIGN,
                 .iterate_transfer_mask = BIT(0),
+                .transfer_count = 2,
                 .transfers              = {
                         {
-                                .len = 1,
                                 .tx_buf = TX(64),
                         },
                         {
@@ -150,13 +149,13 @@ static struct spi_test spi_tests[] = {
                 .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),
                         },
                         {
-                                .len = 1,
                                 .tx_buf = TX(64),
                         },
                 },
@@ -167,13 +166,12 @@ static struct spi_test spi_tests[] = {
                 .iterate_len    = { ITERATE_MAX_LEN },
                 .iterate_tx_align = ITERATE_ALIGN,
                 .iterate_transfer_mask = BIT(0) | BIT(1),
+                .transfer_count = 2,
                 .transfers              = {
                         {
-                                .len = 1,
                                 .tx_buf = TX(0),
                         },
                         {
-                                .len = 1,
                                 .rx_buf = RX(0),
                         },
                 },
@@ -184,9 +182,9 @@ static struct spi_test spi_tests[] = {
                 .iterate_len    = { ITERATE_MAX_LEN },
                 .iterate_tx_align = ITERATE_ALIGN,
                 .iterate_transfer_mask = BIT(0),
+                .transfer_count = 2,
                 .transfers              = {
                         {
-                                .len = 1,
                                 .tx_buf = TX(0),
                         },
                         {
@@ -201,13 +199,13 @@ static struct spi_test spi_tests[] = {
                 .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),
                         },
                         {
-                                .len = 1,
                                 .rx_buf = RX(0),
                         },
                 },
@@ -218,14 +216,13 @@ static struct spi_test spi_tests[] = {
                 .iterate_len    = { ITERATE_LEN },
                 .iterate_tx_align = ITERATE_ALIGN,
                 .iterate_transfer_mask = BIT(0) | BIT(1),
+                .transfer_count = 2,
                 .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
                                  */
@@ -240,9 +237,9 @@ static struct spi_test spi_tests[] = {
                 .iterate_len    = { ITERATE_MAX_LEN },
                 .iterate_tx_align = ITERATE_ALIGN,
                 .iterate_transfer_mask = BIT(0),
+                .transfer_count = 2,
                 .transfers              = {
                         {
-                                .len = 1,
                                 /* making sure we align without overwrite */
                                 .tx_buf = TX(1024),
                                 .rx_buf = RX(1024),
@@ -261,6 +258,7 @@ static struct spi_test spi_tests[] = {
                 .iterate_len    = { ITERATE_MAX_LEN },
                 .iterate_tx_align = ITERATE_ALIGN,
                 .iterate_transfer_mask = BIT(1),
+                .transfer_count = 2,
                 .transfers              = {
                         {
                                 .len = 1,
@@ -268,7 +266,6 @@ static struct spi_test spi_tests[] = {
                                 .rx_buf = RX(0),
                         },
                         {
-                                .len = 1,
                                 /* making sure we align without overwrite */
                                 .tx_buf = TX(1024),
                                 .rx_buf = RX(1024),
@@ -503,7 +500,7 @@ static int spi_test_check_loopback_result(struct spi_device *spi,
         /* 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)
+                if (!xfer->len || !xfer->rx_buf)
                         continue;
                 /* so depending on tx_buf we need to handle things */
                 if (xfer->tx_buf) {
@@ -745,15 +742,6 @@ static int spi_test_run_iter(struct spi_device *spi,
         /* 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
          */
@@ -799,8 +787,7 @@ static int spi_test_run_iter(struct spi_device *spi,
                 /* only when bit in transfer mask is set */
                 if (!(test.iterate_transfer_mask & BIT(i)))
                         continue;
-                if (len)
-                        test.transfers[i].len = 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)
@@ -910,15 +897,6 @@ int spi_test_run_test(struct spi_device *spi, const struct spi_test *test,
         /* 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 ?                                \
@@ -928,7 +906,8 @@ int spi_test_run_test(struct spi_device *spi, const struct spi_test *test,
                         1);                                             \
             var++)
 
-        FOR_EACH_ITERATE(len, 0) {
+        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 */
diff --git a/drivers/spi/spi-test.h b/drivers/spi/spi-test.h
index 922c52833239..2dd569138880 100644
--- a/drivers/spi/spi-test.h
+++ b/drivers/spi/spi-test.h
@@ -48,9 +48,8 @@
  *
  * @msg:              a template @spi_message usedfor the default settings
  * @transfers:        array of @spi_transfers that are part of the
- *                    resulting spi_message. The first transfer with len == 0
- *                    signifies the end of the list
- * @transfer_count:   normally computed number of transfers with len > 0
+ *                    resulting spi_message.
+ * @transfer_count:   number of transfers
  *
  * @run_test:         run a specific spi_test - this allows to override
  *                    the default implementation of @spi_test_run_transfer
@@ -62,8 +61,7 @@
  * @expected_return:  the expected return code - in some cases we want to
  *                    test also for error conditions
  *
- * @iterate_len:      list of length to iterate on (in addition to the
- *                    explicitly set @spi_transfer.len)
+ * @iterate_len:      list of length to iterate on
  * @iterate_tx_align: change the alignment of @spi_transfer.tx_buf
  *                    for all values in the below range if set.
  *                    the ranges are:
@@ -89,7 +87,7 @@ struct spi_test {
         int (*execute_msg)(struct spi_device *spi, struct spi_test *test,
                            void *tx, void *rx);
         int expected_return;
-        /* iterate over all the non-zero values */
+        /* iterate over all values, terminated by a -1 */
         int iterate_len[SPI_TEST_MAX_ITERATE];
         int iterate_tx_align;
         int iterate_rx_align;
@@ -126,11 +124,12 @@ int spi_test_execute_msg(struct spi_device *spi,
 int spi_test_run_tests(struct spi_device *spi,
                        struct spi_test *tests);
 
-/* some of the default @spi_transfer.len to test */
-#define ITERATE_LEN 2, 3, 7, 11, 16, 31, 32, 64, 97, 128, 251, 256, \
+#define ITERATE_LEN_LIST 1, 2, 3, 7, 11, 16, 31, 32, 64, 97, 128, 251, 256, \
                 1021, 1024, 1031, 4093, PAGE_SIZE, 4099, 65536, 65537
-
-#define ITERATE_MAX_LEN ITERATE_LEN, SPI_TEST_MAX_SIZE - 1, SPI_TEST_MAX_SIZE
+/* some of the default @spi_transfer.len to test, terminated by a -1 */
+#define ITERATE_LEN ITERATE_LEN_LIST, -1
+#define ITERATE_MAX_LEN ITERATE_LEN_LIST, (SPI_TEST_MAX_SIZE - 1), \
+                SPI_TEST_MAX_SIZE, -1
 
 /* the default alignment to test */
 #define ITERATE_ALIGN sizeof(int)