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authorFelipe Balbi <balbi@ti.com>2012-01-02 13:35:41 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2012-01-04 15:52:42 -0800
commit18b7ede5f7ee2092aedcb578d3ac30bd5d4fc23c (patch)
treea49fe4ec2a86b37c8bed5041b8314c118b1ebead /include/linux/usb/ch9.h
parente28dbb0661ca49ada2d6a307a1ec93dd75d515e0 (diff)
usb: ch9: fix up MaxStreams helper
According to USB 3.0 Specification Table 9-22, if bmAttributes [4:0] are set to zero, it means "no streams supported", but the way this helper was defined on Linux, we will *always* have one stream which might cause several problems. For example on DWC3, we would tell the controller endpoint has streams enabled and yet start transfers with Stream ID set to 0, which would goof up the host side. While doing that, convert the macro to an inline function due to the different checks we now need. Signed-off-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'include/linux/usb/ch9.h')
-rw-r--r--include/linux/usb/ch9.h20
1 files changed, 19 insertions, 1 deletions
diff --git a/include/linux/usb/ch9.h b/include/linux/usb/ch9.h
index d5da6c68c250..61b29057b054 100644
--- a/include/linux/usb/ch9.h
+++ b/include/linux/usb/ch9.h
@@ -605,8 +605,26 @@ struct usb_ss_ep_comp_descriptor {
} __attribute__ ((packed));
#define USB_DT_SS_EP_COMP_SIZE 6
+
/* Bits 4:0 of bmAttributes if this is a bulk endpoint */
-#define USB_SS_MAX_STREAMS(p) (1 << ((p) & 0x1f))
+static inline int
+usb_ss_max_streams(const struct usb_ss_ep_comp_descriptor *comp)
+{
+ int max_streams;
+
+ if (!comp)
+ return 0;
+
+ max_streams = comp->bmAttributes & 0x1f;
+
+ if (!max_streams)
+ return 0;
+
+ max_streams = 1 << max_streams;
+
+ return max_streams;
+}
+
/* Bits 1:0 of bmAttributes if this is an isoc endpoint */
#define USB_SS_MULT(p) (1 + ((p) & 0x3))