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client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by DS1PEPF00017096.mail.protection.outlook.com (10.167.18.100) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9137.12 via Frontend Transport; Mon, 22 Sep 2025 21:09:30 +0000 Received: from [172.31.131.67] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Mon, 22 Sep 2025 14:09:28 -0700 Message-ID: <0a95bc03-883c-4c84-8131-7a09cdb90be2@amd.com> Date: Mon, 22 Sep 2025 16:09:28 -0500 Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: "Cheatham, Benjamin" Subject: Re: [PATCH v18 11/20] cxl: Define a driver interface for DPA allocation To: CC: , , , , , , , , References: <20250918091746.2034285-1-alejandro.lucero-palau@amd.com> <20250918091746.2034285-12-alejandro.lucero-palau@amd.com> Content-Language: en-US In-Reply-To: <20250918091746.2034285-12-alejandro.lucero-palau@amd.com> Content-Type: text/plain; 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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Sep 2025 21:09:30.2210 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: cd1d8c9d-2499-43fc-f391-08ddfa1c5248 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: DS1PEPF00017096.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB8820 On 9/18/2025 4:17 AM, alejandro.lucero-palau@amd.com wrote: > From: Alejandro Lucero > > Region creation involves finding available DPA (device-physical-address) > capacity to map into HPA (host-physical-address) space. > > In order to support CXL Type2 devices, define an API, cxl_request_dpa(), > that tries to allocate the DPA memory the driver requires to operate.The > memory requested should not be bigger than the max available HPA obtained > previously with cxl_get_hpa_freespace(). > > Based on https://lore.kernel.org/linux-cxl/168592158743.1948938.7622563891193802610.stgit@dwillia2-xfh.jf.intel.com/ > > Signed-off-by: Alejandro Lucero > --- > drivers/cxl/core/hdm.c | 83 ++++++++++++++++++++++++++++++++++++++++++ > drivers/cxl/cxl.h | 1 + > include/cxl/cxl.h | 5 +++ > 3 files changed, 89 insertions(+) > > diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c > index e9e1d555cec6..d1b1d8ab348a 100644 > --- a/drivers/cxl/core/hdm.c > +++ b/drivers/cxl/core/hdm.c > @@ -3,6 +3,7 @@ > #include > #include > #include > +#include > > #include "cxlmem.h" > #include "core.h" > @@ -556,6 +557,13 @@ bool cxl_resource_contains_addr(const struct resource *res, const resource_size_ > return resource_contains(res, &_addr); > } > > +/** > + * cxl_dpa_free - release DPA (Device Physical Address) > + * > + * @cxled: endpoint decoder linked to the DPA > + * > + * Returns 0 or error. > + */ Don't think you need this comment; it's not adding anything you can't get by just looking at the function header.