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-rw-r--r--drivers/thunderbolt/cap.c243
1 files changed, 243 insertions, 0 deletions
diff --git a/drivers/thunderbolt/cap.c b/drivers/thunderbolt/cap.c
new file mode 100644
index 000000000..8ecd610c6
--- /dev/null
+++ b/drivers/thunderbolt/cap.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Thunderbolt driver - capabilities lookup
+ *
+ * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
+ * Copyright (C) 2018, Intel Corporation
+ */
+
+#include <linux/slab.h>
+#include <linux/errno.h>
+
+#include "tb.h"
+
+#define CAP_OFFSET_MAX 0xff
+#define VSE_CAP_OFFSET_MAX 0xffff
+#define TMU_ACCESS_EN BIT(20)
+
+static int tb_port_enable_tmu(struct tb_port *port, bool enable)
+{
+ struct tb_switch *sw = port->sw;
+ u32 value, offset;
+ int ret;
+
+ /*
+ * Legacy devices need to have TMU access enabled before port
+ * space can be fully accessed.
+ */
+ if (tb_switch_is_light_ridge(sw))
+ offset = 0x26;
+ else if (tb_switch_is_eagle_ridge(sw))
+ offset = 0x2a;
+ else
+ return 0;
+
+ ret = tb_sw_read(sw, &value, TB_CFG_SWITCH, offset, 1);
+ if (ret)
+ return ret;
+
+ if (enable)
+ value |= TMU_ACCESS_EN;
+ else
+ value &= ~TMU_ACCESS_EN;
+
+ return tb_sw_write(sw, &value, TB_CFG_SWITCH, offset, 1);
+}
+
+static void tb_port_dummy_read(struct tb_port *port)
+{
+ /*
+ * When reading from next capability pointer location in port
+ * config space the read data is not cleared on LR. To avoid
+ * reading stale data on next read perform one dummy read after
+ * port capabilities are walked.
+ */
+ if (tb_switch_is_light_ridge(port->sw)) {
+ u32 dummy;
+
+ tb_port_read(port, &dummy, TB_CFG_PORT, 0, 1);
+ }
+}
+
+/**
+ * tb_port_next_cap() - Return next capability in the linked list
+ * @port: Port to find the capability for
+ * @offset: Previous capability offset (%0 for start)
+ *
+ * Returns dword offset of the next capability in port config space
+ * capability list and returns it. Passing %0 returns the first entry in
+ * the capability list. If no next capability is found returns %0. In case
+ * of failure returns negative errno.
+ */
+int tb_port_next_cap(struct tb_port *port, unsigned int offset)
+{
+ struct tb_cap_any header;
+ int ret;
+
+ if (!offset)
+ return port->config.first_cap_offset;
+
+ ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
+ if (ret)
+ return ret;
+
+ return header.basic.next;
+}
+
+static int __tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
+{
+ int offset = 0;
+
+ do {
+ struct tb_cap_any header;
+ int ret;
+
+ offset = tb_port_next_cap(port, offset);
+ if (offset < 0)
+ return offset;
+
+ ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
+ if (ret)
+ return ret;
+
+ if (header.basic.cap == cap)
+ return offset;
+ } while (offset > 0);
+
+ return -ENOENT;
+}
+
+/**
+ * tb_port_find_cap() - Find port capability
+ * @port: Port to find the capability for
+ * @cap: Capability to look
+ *
+ * Returns offset to start of capability or %-ENOENT if no such
+ * capability was found. Negative errno is returned if there was an
+ * error.
+ */
+int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
+{
+ int ret;
+
+ ret = tb_port_enable_tmu(port, true);
+ if (ret)
+ return ret;
+
+ ret = __tb_port_find_cap(port, cap);
+
+ tb_port_dummy_read(port);
+ tb_port_enable_tmu(port, false);
+
+ return ret;
+}
+
+/**
+ * tb_switch_next_cap() - Return next capability in the linked list
+ * @sw: Switch to find the capability for
+ * @offset: Previous capability offset (%0 for start)
+ *
+ * Finds dword offset of the next capability in router config space
+ * capability list and returns it. Passing %0 returns the first entry in
+ * the capability list. If no next capability is found returns %0. In case
+ * of failure returns negative errno.
+ */
+int tb_switch_next_cap(struct tb_switch *sw, unsigned int offset)
+{
+ struct tb_cap_any header;
+ int ret;
+
+ if (!offset)
+ return sw->config.first_cap_offset;
+
+ ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
+ if (ret)
+ return ret;
+
+ switch (header.basic.cap) {
+ case TB_SWITCH_CAP_TMU:
+ ret = header.basic.next;
+ break;
+
+ case TB_SWITCH_CAP_VSE:
+ if (!header.extended_short.length)
+ ret = header.extended_long.next;
+ else
+ ret = header.extended_short.next;
+ break;
+
+ default:
+ tb_sw_dbg(sw, "unknown capability %#x at %#x\n",
+ header.basic.cap, offset);
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret >= VSE_CAP_OFFSET_MAX ? 0 : ret;
+}
+
+/**
+ * tb_switch_find_cap() - Find switch capability
+ * @sw: Switch to find the capability for
+ * @cap: Capability to look
+ *
+ * Returns offset to start of capability or %-ENOENT if no such
+ * capability was found. Negative errno is returned if there was an
+ * error.
+ */
+int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
+{
+ int offset = 0;
+
+ do {
+ struct tb_cap_any header;
+ int ret;
+
+ offset = tb_switch_next_cap(sw, offset);
+ if (offset < 0)
+ return offset;
+
+ ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
+ if (ret)
+ return ret;
+
+ if (header.basic.cap == cap)
+ return offset;
+ } while (offset);
+
+ return -ENOENT;
+}
+
+/**
+ * tb_switch_find_vse_cap() - Find switch vendor specific capability
+ * @sw: Switch to find the capability for
+ * @vsec: Vendor specific capability to look
+ *
+ * Functions enumerates vendor specific capabilities (VSEC) of a switch
+ * and returns offset when capability matching @vsec is found. If no
+ * such capability is found returns %-ENOENT. In case of error returns
+ * negative errno.
+ */
+int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
+{
+ int offset = 0;
+
+ do {
+ struct tb_cap_any header;
+ int ret;
+
+ offset = tb_switch_next_cap(sw, offset);
+ if (offset < 0)
+ return offset;
+
+ ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
+ if (ret)
+ return ret;
+
+ if (header.extended_short.cap == TB_SWITCH_CAP_VSE &&
+ header.extended_short.vsec_id == vsec)
+ return offset;
+ } while (offset);
+
+ return -ENOENT;
+}