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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/thunderbolt/cap.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/thunderbolt/cap.c')
-rw-r--r--kernel/drivers/thunderbolt/cap.c116
1 files changed, 116 insertions, 0 deletions
diff --git a/kernel/drivers/thunderbolt/cap.c b/kernel/drivers/thunderbolt/cap.c
new file mode 100644
index 000000000..a7b47e7cd
--- /dev/null
+++ b/kernel/drivers/thunderbolt/cap.c
@@ -0,0 +1,116 @@
+/*
+ * Thunderbolt Cactus Ridge driver - capabilities lookup
+ *
+ * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
+ */
+
+#include <linux/slab.h>
+#include <linux/errno.h>
+
+#include "tb.h"
+
+
+struct tb_cap_any {
+ union {
+ struct tb_cap_basic basic;
+ struct tb_cap_extended_short extended_short;
+ struct tb_cap_extended_long extended_long;
+ };
+} __packed;
+
+static bool tb_cap_is_basic(struct tb_cap_any *cap)
+{
+ /* basic.cap is u8. This checks only the lower 8 bit of cap. */
+ return cap->basic.cap != 5;
+}
+
+static bool tb_cap_is_long(struct tb_cap_any *cap)
+{
+ return !tb_cap_is_basic(cap)
+ && cap->extended_short.next == 0
+ && cap->extended_short.length == 0;
+}
+
+static enum tb_cap tb_cap(struct tb_cap_any *cap)
+{
+ if (tb_cap_is_basic(cap))
+ return cap->basic.cap;
+ else
+ /* extended_short/long have cap at the same offset. */
+ return cap->extended_short.cap;
+}
+
+static u32 tb_cap_next(struct tb_cap_any *cap, u32 offset)
+{
+ int next;
+ if (offset == 1) {
+ /*
+ * The first pointer is part of the switch header and always
+ * a simple pointer.
+ */
+ next = cap->basic.next;
+ } else {
+ /*
+ * Somehow Intel decided to use 3 different types of capability
+ * headers. It is not like anyone could have predicted that
+ * single byte offsets are not enough...
+ */
+ if (tb_cap_is_basic(cap))
+ next = cap->basic.next;
+ else if (!tb_cap_is_long(cap))
+ next = cap->extended_short.next;
+ else
+ next = cap->extended_long.next;
+ }
+ /*
+ * "Hey, we could terminate some capability lists with a null offset
+ * and others with a pointer to the last element." - "Great idea!"
+ */
+ if (next == offset)
+ return 0;
+ return next;
+}
+
+/**
+ * tb_find_cap() - find a capability
+ *
+ * Return: Returns a positive offset if the capability was found and 0 if not.
+ * Returns an error code on failure.
+ */
+int tb_find_cap(struct tb_port *port, enum tb_cfg_space space, enum tb_cap cap)
+{
+ u32 offset = 1;
+ struct tb_cap_any header;
+ int res;
+ int retries = 10;
+ while (retries--) {
+ res = tb_port_read(port, &header, space, offset, 1);
+ if (res) {
+ /* Intel needs some help with linked lists. */
+ if (space == TB_CFG_PORT && offset == 0xa
+ && port->config.type == TB_TYPE_DP_HDMI_OUT) {
+ offset = 0x39;
+ continue;
+ }
+ return res;
+ }
+ if (offset != 1) {
+ if (tb_cap(&header) == cap)
+ return offset;
+ if (tb_cap_is_long(&header)) {
+ /* tb_cap_extended_long is 2 dwords */
+ res = tb_port_read(port, &header, space,
+ offset, 2);
+ if (res)
+ return res;
+ }
+ }
+ offset = tb_cap_next(&header, offset);
+ if (!offset)
+ return 0;
+ }
+ tb_port_WARN(port,
+ "run out of retries while looking for cap %#x in config space %d, last offset: %#x\n",
+ cap, space, offset);
+ return -EIO;
+}