test/py: mmc: Add 'mmc read' performance check

Add option to the mmc rd test to check the duration of the
execution of the mmc read command. This allows intercepting
read performance regressions.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/py/tests/test_mmc_rd.py b/test/py/tests/test_mmc_rd.py
index aba512a..2dc715b 100644
--- a/test/py/tests/test_mmc_rd.py
+++ b/test/py/tests/test_mmc_rd.py
@@ -6,6 +6,7 @@
 # read if the test configuration contains a CRC of the expected data.
 
 import pytest
+import time
 import u_boot_utils
 
 """
@@ -187,6 +188,7 @@
     sector = env__mmc_rd_config.get('sector', 0)
     count_sectors = env__mmc_rd_config.get('count', 1)
     expected_crc32 = env__mmc_rd_config.get('crc32', None)
+    read_duration_max = env__mmc_rd_config.get('read_duration_max', 0)
 
     count_bytes = count_sectors * 512
     bcfg = u_boot_console.config.buildconfig
@@ -213,7 +215,9 @@
 
     # Read data
     cmd = 'mmc read %s %x %x' % (addr, sector, count_sectors)
+    tstart = time.time()
     response = u_boot_console.run_command(cmd)
+    tend = time.time()
     good_response = 'MMC read: dev # %d, block # %d, count %d ... %d blocks read: OK' % (
         devid, sector, count_sectors, count_sectors)
     assert good_response in response
@@ -226,3 +230,10 @@
             assert expected_crc32 in response
         else:
             u_boot_console.log.warning('CONFIG_CMD_CRC32 != y: Skipping check')
+
+    # Check if the command did not take too long
+    if read_duration_max:
+        elapsed = tend - tstart
+        u_boot_console.log.info('Reading %d bytes took %f seconds' %
+                                (count_bytes, elapsed))
+        assert elapsed <= (read_duration_max - 0.01)