From patchwork Tue Dec 19 07:15:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mika Westerberg X-Patchwork-Id: 13497920 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 765B8C2D3 for ; Tue, 19 Dec 2023 07:15:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="FWAiaavo" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1702970135; x=1734506135; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=q/c2fEz4rScCXXn6dyUsZAStkjXTa7aPMHV7hjYbCUs=; b=FWAiaavoHUm1xX4ukhHHo1T4QOq2BhWBDrsomeAxD0M6gpbPlK1lFE22 HaPNfrQxVlyodAk3PZbBPDgzCYFwmiSUWbbNsET2tOoxU7o5MUCSJLJg3 Obj3BsZMQxzzB64/htkt8/RSzLVu4n2PAIcyN/h5ainLlvfdhwBLB+4hT YiDEAuDDV9++DmMAHQHFfJZe6VPCRUkHeNvlqv3tNCodiyydskHbPzct4 Bl9d0TET1FF7Ob56aWA3JkXmVDV19oxNxF6LeJ46ay42bOw+5A4m3kKJj 0oN0pox1YxP23ufeor6hjB92eilL4LMq6xBBkXEpY5jmr+IKbkQK7gdBM Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10928"; a="386040199" X-IronPort-AV: E=Sophos;i="6.04,287,1695711600"; d="scan'208";a="386040199" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Dec 2023 23:15:34 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10928"; a="810124926" X-IronPort-AV: E=Sophos;i="6.04,287,1695711600"; d="scan'208";a="810124926" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga001.jf.intel.com with ESMTP; 18 Dec 2023 23:15:32 -0800 Received: by black.fi.intel.com (Postfix, from userid 1001) id 69B7023A; Tue, 19 Dec 2023 09:15:31 +0200 (EET) From: Mika Westerberg To: linux-usb@vger.kernel.org Cc: Yehezkel Bernat , Michael Jamet , Lukas Wunner , Andreas Noever , Gil Fine , Mika Westerberg Subject: [PATCH] thunderbolt: Keep link as asymmetric if preferred by hardware Date: Tue, 19 Dec 2023 09:15:31 +0200 Message-ID: <20231219071531.2375978-1-mika.westerberg@linux.intel.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Gil Fine In case of the link is brought up as asymmetric (due to hardware preference), we honor that and don't transition it to symmetric, unless a router with symmetric link got plugged below, in the topology (and a bandwidth allows transition to symmetric). Signed-off-by: Gil Fine Signed-off-by: Mika Westerberg --- drivers/thunderbolt/switch.c | 13 +++++++++++++ drivers/thunderbolt/tb.c | 28 +++++++++++++++++++++------- drivers/thunderbolt/tb.h | 2 ++ 3 files changed, 36 insertions(+), 7 deletions(-) diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c index dbab551ac7b3..900114ba4371 100644 --- a/drivers/thunderbolt/switch.c +++ b/drivers/thunderbolt/switch.c @@ -2773,6 +2773,19 @@ static void tb_switch_link_init(struct tb_switch *sw) if (down->dual_link_port) down->dual_link_port->bonded = bonded; tb_port_update_credits(down); + + if (tb_port_get_link_generation(up) < 4) + return; + + /* + * Set the Gen 4 preferred link width. This is what the router + * prefers when the link is brought up. If the router does not + * support asymmetric link configuration, this also will be set + * to TB_LINK_WIDTH_DUAL. + */ + sw->preferred_link_width = sw->link_width; + tb_sw_dbg(sw, "preferred link width %s\n", + tb_width_name(sw->preferred_link_width)); } /** diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c index 0a32e7ec4dc0..846d2813bb1a 100644 --- a/drivers/thunderbolt/tb.c +++ b/drivers/thunderbolt/tb.c @@ -1183,14 +1183,15 @@ static int tb_configure_asym(struct tb *tb, struct tb_port *src_port, * @dst_port: Destination adapter * @requested_up: New lower bandwidth request upstream (Mb/s) * @requested_down: New lower bandwidth request downstream (Mb/s) + * @keep_asym: Keep asymmetric link if preferred * * Goes over each link from @src_port to @dst_port and tries to * transition the link to symmetric if the currently consumed bandwidth - * allows. + * allows and link asymmetric preference is ignored (if @keep_asym is %false). */ static int tb_configure_sym(struct tb *tb, struct tb_port *src_port, struct tb_port *dst_port, int requested_up, - int requested_down) + int requested_down, bool keep_asym) { bool clx = false, clx_disabled = false, downstream; struct tb_switch *sw; @@ -1239,6 +1240,19 @@ static int tb_configure_sym(struct tb *tb, struct tb_port *src_port, if (up->sw->link_width == TB_LINK_WIDTH_DUAL) continue; + /* + * Here consumed < threshold so we can transition the + * link to symmetric. + * + * However, if the router prefers asymmetric link we + * honor that (unless @keep_asym is %false). + */ + if (keep_asym && + up->sw->preferred_link_width > TB_LINK_WIDTH_DUAL) { + tb_sw_dbg(up->sw, "keeping preferred asymmetric link\n"); + continue; + } + /* Disable CL states before doing any transitions */ if (!clx_disabled) { clx = tb_disable_clx(sw); @@ -1292,7 +1306,7 @@ static void tb_configure_link(struct tb_port *down, struct tb_port *up, struct tb_port *host_port; host_port = tb_port_at(tb_route(sw), tb->root_switch); - tb_configure_sym(tb, host_port, up, 0, 0); + tb_configure_sym(tb, host_port, up, 0, 0, false); } /* Set the link configured */ @@ -1477,7 +1491,7 @@ static void tb_deactivate_and_free_tunnel(struct tb_tunnel *tunnel) * If bandwidth on a link is < asym_threshold * transition the link to symmetric. */ - tb_configure_sym(tb, src_port, dst_port, 0, 0); + tb_configure_sym(tb, src_port, dst_port, 0, 0, true); /* Now we can allow the domain to runtime suspend again */ pm_runtime_mark_last_busy(&dst_port->sw->dev); pm_runtime_put_autosuspend(&dst_port->sw->dev); @@ -2299,7 +2313,7 @@ static int tb_alloc_dp_bandwidth(struct tb_tunnel *tunnel, int *requested_up, * If bandwidth on a link is < asym_threshold transition * the link to symmetric. */ - tb_configure_sym(tb, in, out, *requested_up, *requested_down); + tb_configure_sym(tb, in, out, *requested_up, *requested_down, true); /* * If requested bandwidth is less or equal than what is * currently allocated to that tunnel we simply change @@ -2342,7 +2356,7 @@ static int tb_alloc_dp_bandwidth(struct tb_tunnel *tunnel, int *requested_up, ret = tb_configure_asym(tb, in, out, *requested_up, *requested_down); if (ret) { - tb_configure_sym(tb, in, out, 0, 0); + tb_configure_sym(tb, in, out, 0, 0, true); return ret; } @@ -2350,7 +2364,7 @@ static int tb_alloc_dp_bandwidth(struct tb_tunnel *tunnel, int *requested_up, requested_down); if (ret) { tb_tunnel_warn(tunnel, "failed to allocate bandwidth\n"); - tb_configure_sym(tb, in, out, 0, 0); + tb_configure_sym(tb, in, out, 0, 0, true); } } else { ret = -ENOBUFS; diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h index 1760c21e5b12..997c5a536905 100644 --- a/drivers/thunderbolt/tb.h +++ b/drivers/thunderbolt/tb.h @@ -125,6 +125,7 @@ struct tb_switch_tmu { * @device_name: Name of the device (or %NULL if not known) * @link_speed: Speed of the link in Gb/s * @link_width: Width of the upstream facing link + * @preferred_link_width: Router preferred link width (only set for Gen 4 links) * @link_usb4: Upstream link is USB4 * @generation: Switch Thunderbolt generation * @cap_plug_events: Offset to the plug events capability (%0 if not found) @@ -178,6 +179,7 @@ struct tb_switch { const char *device_name; unsigned int link_speed; enum tb_link_width link_width; + enum tb_link_width preferred_link_width; bool link_usb4; unsigned int generation; int cap_plug_events;