mmc: core: add random fault injection

This adds support to inject data errors after a completed host transfer.
The mmc core will return error even though the host transfer is successful.
This simple fault injection proved to be very useful to test the
non-blocking error handling in the mmc_blk_issue_rw_rq().
Random faults can also test how the host driver handles pre_req()
and post_req() in case of errors.

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index c0cb9c4bc46d..1c7dbbf9e449 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1070,6 +1070,17 @@ config FAIL_IO_TIMEOUT
           Only works with drivers that use the generic timeout handling,
           for others it wont do anything.
 
+config FAIL_MMC_REQUEST
+        bool "Fault-injection capability for MMC IO"
+        select DEBUG_FS
+        depends on FAULT_INJECTION && MMC
+        help
+          Provide fault-injection capability for MMC IO.
+          This will make the mmc core return data errors. This is
+          useful to test the error handling in the mmc block device
+          and to test how the mmc host driver handles retries from
+          the block device.
+
 config FAULT_INJECTION_DEBUG_FS
         bool "Debugfs entries for fault-injection capabilities"
         depends on FAULT_INJECTION && SYSFS && DEBUG_FS