From patchwork Thu Dec 12 14:53:47 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thierry Reding X-Patchwork-Id: 3332531 Return-Path: X-Original-To: patchwork-dri-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id A5B97C0D4A for ; Thu, 12 Dec 2013 14:55:27 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E06B620792 for ; Thu, 12 Dec 2013 14:55:22 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id ADE4220786 for ; Thu, 12 Dec 2013 14:55:21 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9FC77FB400; Thu, 12 Dec 2013 06:55:14 -0800 (PST) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-bk0-f51.google.com (mail-bk0-f51.google.com [209.85.214.51]) by gabe.freedesktop.org (Postfix) with ESMTP id 6E773FA7DE for ; Thu, 12 Dec 2013 06:55:07 -0800 (PST) Received: by mail-bk0-f51.google.com with SMTP id 6so909455bkj.38 for ; Thu, 12 Dec 2013 06:55:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:subject:date:message-id:in-reply-to:references; bh=smj3VT8c832REDUCt2CGuuIRa0Qqby62Ng5r4/ILaQI=; b=dWNjqbS/h0vW9B8LG4UfJ3oIjqG2Bq7kkVC4ihS+C0YmPK4pD7Or++kGatXyqZy0P/ uSZ1Gp0/bNhxKy/fN+UYwimSMc8oIyISJiVUa9LFhJ2b0C2kf34P/nvte7YTgLru78l8 PdeOJa8uCHNO237K9z029+IZnulGGM0RxrKrMxv5a5yXhTB9nwNyisSEXuMxL6b8QMzQ 7zWewFv/LZgvXvcf6yn/CJtS7J+noD81F1TKhf2QyK5aQmiY5P/XO3aMbD1p2X/IaE1c F0nR9kF0cpCQLItOJQR75rzFrGkiDAd3vzVeg1bf6SucMQdNbw42UaE7kc/00tTx6hrf jteA== X-Received: by 10.205.12.133 with SMTP id pi5mr774120bkb.54.1386860106564; Thu, 12 Dec 2013 06:55:06 -0800 (PST) Received: from localhost (port-31954.pppoe.wtnet.de. [46.59.175.170]) by mx.google.com with ESMTPSA id lr9sm18564023bkb.2.2013.12.12.06.55.04 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 12 Dec 2013 06:55:05 -0800 (PST) From: Thierry Reding To: dri-devel@lists.freedesktop.org Subject: [PATCH 1/4] drm/dp: Add AUX channel infrastructure Date: Thu, 12 Dec 2013 15:53:47 +0100 Message-Id: <1386860030-1840-2-git-send-email-treding@nvidia.com> X-Mailer: git-send-email 1.8.4.2 In-Reply-To: <1386860030-1840-1-git-send-email-treding@nvidia.com> References: <1386860030-1840-1-git-send-email-treding@nvidia.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dri-devel-bounces@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This is a superset of the current i2c_dp_aux bus functionality and can be used to transfer native AUX in addition to I2C-over-AUX messages. Helpers are provided to read and write the DPCD, either blockwise or byte-wise. Many of the existing helpers for DisplayPort take a copy of a portion of the DPCD and operate on that, without a way to write data back to the DPCD (e.g. for configuration of the link). Subsequent patches will build upon this infrastructure to provide common functionality in a generic way. Signed-off-by: Thierry Reding --- drivers/gpu/drm/drm_dp_helper.c | 50 ++++++++++++++++++++++++ include/drm/drm_dp_helper.h | 85 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 135 insertions(+) diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 9e978aae8972..6c9276098069 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -346,3 +346,53 @@ int drm_dp_bw_code_to_link_rate(u8 link_bw) } } EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate); + +/** + * drm_dp_dpcd_read() - read a series of bytes from the DPCD + * @aux: DisplayPort AUX channel + * @offset: address of the (first) register to read + * @buffer: buffer to store the register values + * @size: number of bytes in @buffer + * + * Returns the number of bytes transferred on success, or a negative error + * code on failure. + */ +ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset, + void *buffer, size_t size) +{ + struct drm_dp_aux_msg msg; + + memset(&msg, 0, sizeof(msg)); + msg.address = offset; + msg.flags = DRM_DP_AUX_NATIVE_READ; + msg.buffer = buffer; + msg.size = size; + + return aux->transfer(aux, &msg); +} +EXPORT_SYMBOL(drm_dp_dpcd_read); + +/** + * drm_dp_dpcd_write() - write a series of bytes to the DPCD + * @aux: DisplayPort AUX channel + * @offset: address of the (first) register to write + * @buffer: buffer containing the values to write + * @size: number of bytes in @buffer + * + * Returns the number of bytes transferred on success, or a negative error + * code on failure. + */ +ssize_t drm_dp_dpcd_write(struct drm_dp_aux *aux, unsigned int offset, + void *buffer, size_t size) +{ + struct drm_dp_aux_msg msg; + + memset(&msg, 0, sizeof(msg)); + msg.address = offset; + msg.flags = DRM_DP_AUX_NATIVE_WRITE; + msg.buffer = buffer; + msg.size = size; + + return aux->transfer(aux, &msg); +} +EXPORT_SYMBOL(drm_dp_dpcd_write); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index a92c3754e3bb..e528b2b64cef 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -397,4 +397,89 @@ drm_dp_enhanced_frame_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) (dpcd[DP_MAX_LANE_COUNT] & DP_ENHANCED_FRAME_CAP); } +/* + * DisplayPort AUX channel + */ + +/* A message is either a native AUX or I2C-over-AUX transaction */ +#define DRM_DP_AUX_MODE_MASK 0x1 +#define DRM_DP_AUX_NATIVE 0x0 +#define DRM_DP_AUX_I2C 0x1 + +/* + * A message can be a read or write transaction. I2C messages can also be + * part of a larger transaction, in which case the MOT flag can be set. + */ +#define DRM_DP_AUX_WRITE (1 << 30) +#define DRM_DP_AUX_I2C_MOT (1 << 31) + +#define DRM_DP_AUX_NATIVE_READ DRM_DP_AUX_NATIVE +#define DRM_DP_AUX_NATIVE_WRITE (DRM_DP_AUX_WRITE | DRM_DP_AUX_NATIVE) + +#define DRM_DP_AUX_ACK (0 << 0) +#define DRM_DP_AUX_NAK (1 << 0) +#define DRM_DP_AUX_DEFER (2 << 0) +#define DRM_DP_AUX_I2C_NAK (3 << 0) +#define DRM_DP_AUX_I2C_DEFER (4 << 0) + +/** + * struct drm_dp_aux_msg - DisplayPort AUX channel transaction + * @address: address of the (first) register to access + * @flags: contains the type of transaction as well as flags (see above) + * @reply: upon completion, contains the reply type of the transaction + * @buffer: pointer to a transmission or reception buffer + * @size: size of @buffer + */ +struct drm_dp_aux_msg { + unsigned int address; + unsigned long flags; + unsigned long reply; + void *buffer; + size_t size; +}; + +/** + * struct drm_dp_aux - DisplayPort AUX channel + * @transfer: transfers a message representing a single AUX transaction + */ +struct drm_dp_aux { + ssize_t (*transfer)(struct drm_dp_aux *aux, + struct drm_dp_aux_msg *msg); +}; + +ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset, + void *buffer, size_t size); +ssize_t drm_dp_dpcd_write(struct drm_dp_aux *aux, unsigned int offset, + void *buffer, size_t size); + +/** + * drm_dp_dpcd_readb() - read a single byte from the DPCD + * @aux: DisplayPort AUX channel + * @offset: address of the register to read + * @valuep: location where the value of the register will be stored + * + * Returns the number of bytes transferred (1) on success, or a negative + * error code on failure. + */ +static inline ssize_t drm_dp_dpcd_readb(struct drm_dp_aux *aux, + unsigned int offset, u8 *valuep) +{ + return drm_dp_dpcd_read(aux, offset, valuep, 1); +} + +/** + * drm_dp_dpcd_writeb() - write a single byte to the DPCD + * @aux: DisplayPort AUX channel + * @offset: address of the register to write + * @valuep: value to write to the register + * + * Returns the number of bytes transferred (1) on success, or a negative + * error code on failure. + */ +static inline ssize_t drm_dp_dpcd_writeb(struct drm_dp_aux *aux, u8 value, + unsigned int offset) +{ + return drm_dp_dpcd_write(aux, offset, &value, 1); +} + #endif /* _DRM_DP_HELPER_H_ */