staging: dwc2: fix off-by-one in check for max_packet_count parameter

Previously, the max_packet_count could be set to 1 << x, where x is the
number of bits available (width + 4 in the code). Since 1 << x requires
x + 1 bits to represent, this will not work. The real maximum value is
(1 << x) - 1. This value is already used the default when the set value
is invalid, but the upper limit for the set value was off-by-one.

This change makes the check the same as the one for max_transfer_size,
which was already correct.

Signed-off-by: Matthijs Kooijman <matthijs@stdin.nl>
Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/dwc2/core.c b/drivers/staging/dwc2/core.c
index a090f79bb5f5306e4671c8f8c6154132803fa710..5f09f47bdf7306817df93379c35e3c0ae6f3f54d 100644 (file)
--- a/drivers/staging/dwc2/core.c
+++ b/drivers/staging/dwc2/core.c
@@ -2209,7 +2209,7 @@ int dwc2_set_param_max_packet_count(struct dwc2_hsotg *hsotg, int val)
                    GHWCFG3_PACKET_SIZE_CNTR_WIDTH_MASK >>
                                GHWCFG3_PACKET_SIZE_CNTR_WIDTH_SHIFT;
 
-       if (val < 15 || val > (1 << (width + 4)))
+       if (val < 15 || val >= (1 << (width + 4)))
                valid = 0;
 
        if (!valid) {