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[05/19] thunderbolt: Do not program NFC buffers for USB4 router protocol adapters

Message ID 20200819115905.59834-6-mika.westerberg@linux.intel.com
State New
Headers show
Series thunderbolt: Power Management improvements | expand

Commit Message

Mika Westerberg Aug. 19, 2020, 11:58 a.m. UTC
USB4 spec says that NFC buffers field is not used for protocol adapters,
only for lane adapters so make tb_port_add_nfc_credits() skip non-lane
adapters in order to follow the spec.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/switch.c | 7 +++++++
 1 file changed, 7 insertions(+)
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Patch

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 698c52775eec..72756c8ceead 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -601,6 +601,13 @@  int tb_port_add_nfc_credits(struct tb_port *port, int credits)
 	if (credits == 0 || port->sw->is_unplugged)
 		return 0;
 
+	/*
+	 * USB4 restricts programming NFC buffers to lane adapters only
+	 * so skip other ports.
+	 */
+	if (tb_switch_is_usb4(port->sw) && !tb_port_is_null(port))
+		return 0;
+
 	nfc_credits = port->config.nfc_credits & ADP_CS_4_NFC_BUFFERS_MASK;
 	nfc_credits += credits;