Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934203AbaFCUFE (ORCPT ); Tue, 3 Jun 2014 16:05:04 -0400 Received: from mail-wi0-f179.google.com ([209.85.212.179]:44660 "EHLO mail-wi0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934074AbaFCUE5 (ORCPT ); Tue, 3 Jun 2014 16:04:57 -0400 From: Andreas Noever To: linux-kernel@vger.kernel.org, Matthew Garrett , Greg KH , Bjorn Helgaas , linux-pci@vger.kernel.org Cc: Andreas Noever Subject: [PATCH v5 06/15] thunderbolt: Add thunderbolt capability handling Date: Tue, 3 Jun 2014 22:04:03 +0200 Message-Id: <1401825852-4745-7-git-send-email-andreas.noever@gmail.com> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1401825852-4745-1-git-send-email-andreas.noever@gmail.com> References: <1401825852-4745-1-git-send-email-andreas.noever@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thunderbolt config areas contain capability lists similar to those found on pci devices. This patch introduces a tb_find_cap utility method to search for capabilities. Signed-off-by: Andreas Noever --- drivers/thunderbolt/Makefile | 2 +- drivers/thunderbolt/cap.c | 116 +++++++++++++++++++++++++++++++++++++++++++ drivers/thunderbolt/tb.h | 2 + 3 files changed, 119 insertions(+), 1 deletion(-) create mode 100644 drivers/thunderbolt/cap.c diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile index 4ac18d9..617b314 100644 --- a/drivers/thunderbolt/Makefile +++ b/drivers/thunderbolt/Makefile @@ -1,3 +1,3 @@ obj-${CONFIG_THUNDERBOLT} := thunderbolt.o -thunderbolt-objs := nhi.o ctl.o tb.o switch.o +thunderbolt-objs := nhi.o ctl.o tb.o switch.o cap.o diff --git a/drivers/thunderbolt/cap.c b/drivers/thunderbolt/cap.c new file mode 100644 index 0000000..a7b47e7 --- /dev/null +++ b/drivers/thunderbolt/cap.c @@ -0,0 +1,116 @@ +/* + * Thunderbolt Cactus Ridge driver - capabilities lookup + * + * Copyright (c) 2014 Andreas Noever + */ + +#include +#include + +#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; +} diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h index 389dbb4..38e4c23 100644 --- a/drivers/thunderbolt/tb.h +++ b/drivers/thunderbolt/tb.h @@ -159,6 +159,8 @@ void thunderbolt_shutdown_and_free(struct tb *tb); struct tb_switch *tb_switch_alloc(struct tb *tb, u64 route); void tb_switch_free(struct tb_switch *sw); +int tb_find_cap(struct tb_port *port, enum tb_cfg_space space, u32 value); + static inline int tb_route_length(u64 route) { -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/