From nobody Mon Feb 9 16:33:31 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2582FEB64D7 for ; Tue, 20 Jun 2023 09:49:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231538AbjFTJtL (ORCPT ); Tue, 20 Jun 2023 05:49:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231750AbjFTJsE (ORCPT ); Tue, 20 Jun 2023 05:48:04 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2587DF4 for ; Tue, 20 Jun 2023 02:48:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=eJgS+ 6QGum3SdDAw+Bqw/GjZ998M8zZs7I/LN1qiwAo=; b=lX5bRoVdowDItdGd7sCi1 A4DlUqhtkvP+cSnITTrEgDjSX3EWwiNSvZfhsb2QwseiN27F+CwYXKSETE+f7eOZ Pam5cWFL/l6mU8APSxf/D4+L4zkbNQ8CPGW+RP0nz6e1WUJueo0gJ+4u9ei8ttT/ M5Ydhx8YWtzW0Ev+dslLw4= Received: from openarena.loongson.cn (unknown [114.242.206.180]) by zwqz-smtp-mta-g4-0 (Coremail) with SMTP id _____wAXg3CldZFkB8yiAQ--.11241S9; Tue, 20 Jun 2023 17:47:18 +0800 (CST) From: Sui Jingfeng <18949883232@163.com> To: Lucas Stach , Russell King , Christian Gmeiner , David Airlie , Daniel Vetter Cc: linux-kernel@vger.kernel.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Sui Jingfeng , Philipp Zabel , Bjorn Helgaas Subject: [PATCH v10 07/11] drm/etnaviv: Add support for the dma coherent device Date: Tue, 20 Jun 2023 17:47:12 +0800 Message-Id: <20230620094716.2231414-8-18949883232@163.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230620094716.2231414-1-18949883232@163.com> References: <20230620094716.2231414-1-18949883232@163.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wAXg3CldZFkB8yiAQ--.11241S9 X-Coremail-Antispam: 1Uf129KBjvJXoW3Gw15tw1rKw15Ww1DKFy8Xwb_yoWfJF48pF s3AFyYyrW8ZFyj9w1xAFn5ZFy3Kw1xWFWFkasrtwn0v3y5tr18try0kFs8CF98Jr1fWrWa qr1qyry3GF1UArJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07j9VycUUUUU= X-Originating-IP: [114.242.206.180] X-CM-SenderInfo: jprymkizyyjjits6il2tof0z/xtbBaQiU0VXl0TKDzwAAs7 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Sui Jingfeng Loongson CPUs maintain cache coherency by hardware, which means that the data in the CPU cache is identical to the data in main system memory. As for the peripheral device, most of Loongson chips chose to define the peripherals as DMA coherent by default, device drivers do not need to maintain the coherency between a processor and an I/O device manually. There are exceptions, for LS2K1000 SoC, part of peripheral device can be configured as DMA non-coherent. But there is no released version of such firmware exist in the market. Peripherals of older LS2K1000 is also DMA non-coherent, but they are nearly outdated. So, those are trivial cases. Nevertheless, kernel space still need to do the probe work, because vivante GPU IP has been integrated into various platform. Hence, this patch add runtime detection code to probe if a specific GPU is DMA coherent, If the answer is yes, we are going to utilize such features. On Loongson platform, When a buffer is accessed by both the GPU and the CPU, the driver should prefer ETNA_BO_CACHED over ETNA_BO_WC. This patch also add a new parameter: etnaviv_param_gpu_coherent, which allow userspace to know if such a feature is available. Because write-combined BO is still preferred in some case, especially where don't need CPU read, for example, uploading compiled shader bin. Cc: Lucas Stach Cc: Christian Gmeiner Cc: Philipp Zabel Cc: Bjorn Helgaas Cc: Daniel Vetter Signed-off-by: Sui Jingfeng --- drivers/gpu/drm/etnaviv/etnaviv_drv.c | 35 +++++++++++++++++++++ drivers/gpu/drm/etnaviv/etnaviv_drv.h | 6 ++++ drivers/gpu/drm/etnaviv/etnaviv_gem.c | 22 ++++++++++--- drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 7 ++++- drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 4 +++ include/uapi/drm/etnaviv_drm.h | 1 + 6 files changed, 70 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnavi= v/etnaviv_drv.c index 0a365e96d371..d8e788aa16cb 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c @@ -5,7 +5,9 @@ =20 #include #include +#include #include +#include #include #include =20 @@ -24,6 +26,34 @@ #include "etnaviv_pci_drv.h" #include "etnaviv_perfmon.h" =20 +static struct device_node *etnaviv_of_first_available_node(void) +{ + struct device_node *core_node; + + for_each_compatible_node(core_node, NULL, "vivante,gc") { + if (of_device_is_available(core_node)) + return core_node; + } + + return NULL; +} + +static bool etnaviv_is_dma_coherent(struct device *dev) +{ + struct device_node *np; + bool coherent; + + np =3D etnaviv_of_first_available_node(); + if (np) { + coherent =3D of_dma_is_coherent(np); + of_node_put(np); + } else { + coherent =3D dev_is_dma_coherent(dev); + } + + return coherent; +} + /* * etnaviv private data construction and destructions: */ @@ -52,6 +82,11 @@ etnaviv_alloc_private(struct device *dev, struct drm_dev= ice *drm) return ERR_PTR(-ENOMEM); } =20 + priv->dma_coherent =3D etnaviv_is_dma_coherent(dev); + + if (priv->dma_coherent) + drm_info(drm, "%s is dma coherent\n", dev_name(dev)); + return priv; } =20 diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.h b/drivers/gpu/drm/etnavi= v/etnaviv_drv.h index 9cd72948cfad..644e5712c050 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.h +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.h @@ -46,6 +46,12 @@ struct etnaviv_drm_private { struct xarray active_contexts; u32 next_context_id; =20 + /* + * If true, the GPU is capable of snooping cpu cache. Here, it + * also means that cache coherency is enforced by the hardware. + */ + bool dma_coherent; + /* list of GEM objects: */ struct mutex gem_lock; struct list_head gem_list; diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnavi= v/etnaviv_gem.c index b5f73502e3dd..39bdc3774f2d 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c @@ -343,6 +343,7 @@ void *etnaviv_gem_vmap(struct drm_gem_object *obj) static void *etnaviv_gem_vmap_impl(struct etnaviv_gem_object *obj) { struct page **pages; + pgprot_t prot; =20 lockdep_assert_held(&obj->lock); =20 @@ -350,8 +351,19 @@ static void *etnaviv_gem_vmap_impl(struct etnaviv_gem_= object *obj) if (IS_ERR(pages)) return NULL; =20 - return vmap(pages, obj->base.size >> PAGE_SHIFT, - VM_MAP, pgprot_writecombine(PAGE_KERNEL)); + switch (obj->flags) { + case ETNA_BO_CACHED: + prot =3D PAGE_KERNEL; + break; + case ETNA_BO_UNCACHED: + prot =3D pgprot_noncached(PAGE_KERNEL); + break; + case ETNA_BO_WC: + default: + prot =3D pgprot_writecombine(PAGE_KERNEL); + } + + return vmap(pages, obj->base.size >> PAGE_SHIFT, VM_MAP, prot); } =20 static inline enum dma_data_direction etnaviv_op_to_dma_dir(u32 op) @@ -369,6 +381,7 @@ int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u3= 2 op, { struct etnaviv_gem_object *etnaviv_obj =3D to_etnaviv_bo(obj); struct drm_device *dev =3D obj->dev; + struct etnaviv_drm_private *priv =3D dev->dev_private; bool write =3D !!(op & ETNA_PREP_WRITE); int ret; =20 @@ -395,7 +408,7 @@ int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u3= 2 op, return ret =3D=3D 0 ? -ETIMEDOUT : ret; } =20 - if (etnaviv_obj->flags & ETNA_BO_CACHED) { + if (!priv->dma_coherent && etnaviv_obj->flags & ETNA_BO_CACHED) { dma_sync_sgtable_for_cpu(dev->dev, etnaviv_obj->sgt, etnaviv_op_to_dma_dir(op)); etnaviv_obj->last_cpu_prep_op =3D op; @@ -408,8 +421,9 @@ int etnaviv_gem_cpu_fini(struct drm_gem_object *obj) { struct drm_device *dev =3D obj->dev; struct etnaviv_gem_object *etnaviv_obj =3D to_etnaviv_bo(obj); + struct etnaviv_drm_private *priv =3D dev->dev_private; =20 - if (etnaviv_obj->flags & ETNA_BO_CACHED) { + if (!priv->dma_coherent && etnaviv_obj->flags & ETNA_BO_CACHED) { /* fini without a prep is almost certainly a userspace error */ WARN_ON(etnaviv_obj->last_cpu_prep_op =3D=3D 0); dma_sync_sgtable_for_device(dev->dev, etnaviv_obj->sgt, diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c b/drivers/gpu/drm/= etnaviv/etnaviv_gem_prime.c index 3524b5811682..754126992264 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c @@ -112,11 +112,16 @@ static const struct etnaviv_gem_ops etnaviv_gem_prime= _ops =3D { struct drm_gem_object *etnaviv_gem_prime_import_sg_table(struct drm_device= *dev, struct dma_buf_attachment *attach, struct sg_table *sgt) { + struct etnaviv_drm_private *priv =3D dev->dev_private; struct etnaviv_gem_object *etnaviv_obj; size_t size =3D PAGE_ALIGN(attach->dmabuf->size); + u32 cache_flags =3D ETNA_BO_WC; int ret, npages; =20 - ret =3D etnaviv_gem_new_private(dev, size, ETNA_BO_WC, + if (priv->dma_coherent) + cache_flags =3D ETNA_BO_CACHED; + + ret =3D etnaviv_gem_new_private(dev, size, cache_flags, &etnaviv_gem_prime_ops, &etnaviv_obj); if (ret < 0) return ERR_PTR(ret); diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnavi= v/etnaviv_gpu.c index d6a21e97feb1..d99ac675ce8b 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c @@ -164,6 +164,10 @@ int etnaviv_gpu_get_param(struct etnaviv_gpu *gpu, u32= param, u64 *value) *value =3D gpu->identity.eco_id; break; =20 + case ETNAVIV_PARAM_GPU_COHERENT: + *value =3D priv->dma_coherent; + break; + default: DBG("%s: invalid param: %u", dev_name(gpu->dev), param); return -EINVAL; diff --git a/include/uapi/drm/etnaviv_drm.h b/include/uapi/drm/etnaviv_drm.h index af024d90453d..76baf45d7158 100644 --- a/include/uapi/drm/etnaviv_drm.h +++ b/include/uapi/drm/etnaviv_drm.h @@ -77,6 +77,7 @@ struct drm_etnaviv_timespec { #define ETNAVIV_PARAM_GPU_PRODUCT_ID 0x1c #define ETNAVIV_PARAM_GPU_CUSTOMER_ID 0x1d #define ETNAVIV_PARAM_GPU_ECO_ID 0x1e +#define ETNAVIV_PARAM_GPU_COHERENT 0x1f =20 #define ETNA_MAX_PIPES 4 =20 --=20 2.25.1