The SoC Hardware Library (HWLIB) configures and controls the SoC Quad Serial Peripheral Interface (SPI) Controllers. The QSPI HWLIB source, can be found in the /ip/altera/hps/altera_hps/hwlib/include/alt_qspi.h file.
In SOC EDS 15.0 and earlier, the definition of the polarity ALT_QSPI_CLK_POLARITY_LOW and ALT_QSPI_CLK_POLARITY_HIGH and their respective values in alt_qspi.h is incorrect.
To work around this problem, edit alt_qspi.h and replace:
ALT_QSPI_CLK_POLARITY_LOW = 0
with
ALT_QSPI_CLK_POLARITY_LOW = 1
and
ALT_QSPI_CLK_POLARITY_HIGH = 1
with
ALT_QSPI_CLK_POLARITY_ HIGH = 0
This problem is scheduled be fixed in a future version of the Altera SoC Embedded Design Suite.