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From:   Hans de Goede <hdegoede@redhat.com>
To:     Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        Mathias Nyman <mathias.nyman@intel.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Guenter Roeck <linux@roeck-us.net>
Cc:     Hans de Goede <hdegoede@redhat.com>,
        platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-usb@vger.kernel.org,
        Mathias Nyman <mathias.nyman@linux.intel.com>
Subject: [PATCH v5 07/12] xhci: Add option to get next extended capability in list by passing id = 0
Date:   Wed, 28 Feb 2018 16:07:44 +0100
Message-Id: <20180228150749.26831-8-hdegoede@redhat.com>
In-Reply-To: <20180228150749.26831-1-hdegoede@redhat.com>
References: <20180228150749.26831-1-hdegoede@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Mathias Nyman <mathias.nyman@linux.intel.com>

Modify xhci_find_next_ext_cap(base, offset, id) to return the next
capability offset if 0 is passed for id. Otherwise it will behave as
previously and return the offset of the next capability with matching id

capability id 0 is not used by xHCI (reserved)

This is useful when we want to loop through all capabilities.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v4:
-Add Andy's Reviewed-by

Changes in v2:
-Added Heikki's Reviewed-by
---
 drivers/usb/host/xhci-ext-caps.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-ext-caps.h b/drivers/usb/host/xhci-ext-caps.h
index bf7316e130d3..631e7cc62604 100644
--- a/drivers/usb/host/xhci-ext-caps.h
+++ b/drivers/usb/host/xhci-ext-caps.h
@@ -84,7 +84,8 @@
  * @base	PCI MMIO registers base address.
  * @start	address at which to start looking, (0 or HCC_PARAMS to start at
  *		beginning of list)
- * @id		Extended capability ID to search for.
+ * @id		Extended capability ID to search for, or 0 for the next
+ *		capability
  *
  * Returns the offset of the next matching extended capability structure.
  * Some capabilities can occur several times, e.g., the XHCI_EXT_CAPS_PROTOCOL,
@@ -110,7 +111,7 @@ static inline int xhci_find_next_ext_cap(void __iomem *base, u32 start, int id)
 		val = readl(base + offset);
 		if (val == ~0)
 			return 0;
-		if (XHCI_EXT_CAPS_ID(val) == id && offset != start)
+		if (offset != start && (id == 0 || XHCI_EXT_CAPS_ID(val) == id))
 			return offset;
 
 		next = XHCI_EXT_CAPS_NEXT(val);
-- 
2.14.3