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Thu, 25 Apr 2024 11:38:27 +0100 From: Shiju Jose To: fan CC: "linux-cxl@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "linux-mm@kvack.org" , "dan.j.williams@intel.com" , "dave@stgolabs.net" , "Jonathan Cameron" , "dave.jiang@intel.com" , "alison.schofield@intel.com" , "vishal.l.verma@intel.com" , "ira.weiny@intel.com" , "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "david@redhat.com" , "Vilas.Sridharan@amd.com" , "leo.duran@amd.com" , "Yazen.Ghannam@amd.com" , "rientjes@google.com" , "jiaqiyan@google.com" , "tony.luck@intel.com" , "Jon.Grimm@amd.com" , "dave.hansen@linux.intel.com" , "rafael@kernel.org" , "lenb@kernel.org" , "naoya.horiguchi@nec.com" , "james.morse@arm.com" , "jthoughton@google.com" , "somasundaram.a@hpe.com" , "erdemaktas@google.com" , "pgonda@google.com" , "duenwen@google.com" , "mike.malvestuto@intel.com" , "gthelen@google.com" , "wschwartz@amperecomputing.com" , "dferguson@amperecomputing.com" , "wbs@os.amperecomputing.com" , tanxiaofei , "Zengtao (B)" , "kangkang.shen@futurewei.com" , wanghuiqiang , Linuxarm Subject: RE: [RFC PATCH v8 03/10] cxl/mbox: Add GET_FEATURE mailbox command Thread-Topic: [RFC PATCH v8 03/10] cxl/mbox: Add GET_FEATURE mailbox command Thread-Index: AQHaknlNjhR9ApEz/Ue7aqewzZ69irF4BeQAgADGYfA= Date: Thu, 25 Apr 2024 10:38:27 +0000 Message-ID: References: <20240419164720.1765-1-shiju.jose@huawei.com> <20240419164720.1765-4-shiju.jose@huawei.com> In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 >-----Original Message----- >From: fan >Sent: 25 April 2024 00:19 >To: Shiju Jose >Cc: linux-cxl@vger.kernel.org; linux-acpi@vger.kernel.org; linux- >mm@kvack.org; dan.j.williams@intel.com; dave@stgolabs.net; Jonathan >Cameron ; dave.jiang@intel.com; >alison.schofield@intel.com; vishal.l.verma@intel.com; ira.weiny@intel.com; >linux-edac@vger.kernel.org; linux-kernel@vger.kernel.org; david@redhat.com= ; >Vilas.Sridharan@amd.com; leo.duran@amd.com; Yazen.Ghannam@amd.com; >rientjes@google.com; jiaqiyan@google.com; tony.luck@intel.com; >Jon.Grimm@amd.com; dave.hansen@linux.intel.com; rafael@kernel.org; >lenb@kernel.org; naoya.horiguchi@nec.com; james.morse@arm.com; >jthoughton@google.com; somasundaram.a@hpe.com; >erdemaktas@google.com; pgonda@google.com; duenwen@google.com; >mike.malvestuto@intel.com; gthelen@google.com; >wschwartz@amperecomputing.com; dferguson@amperecomputing.com; >wbs@os.amperecomputing.com; nifan.cxl@gmail.com; tanxiaofei >; Zengtao (B) ; >kangkang.shen@futurewei.com; wanghuiqiang ; >Linuxarm >Subject: Re: [RFC PATCH v8 03/10] cxl/mbox: Add GET_FEATURE mailbox >command > >On Sat, Apr 20, 2024 at 12:47:12AM +0800, shiju.jose@huawei.com wrote: >> From: Shiju Jose >> >> Add support for GET_FEATURE mailbox command. >> >> CXL spec 3.1 section 8.2.9.6 describes optional device specific features= . >> The settings of a feature can be retrieved using Get Feature command. >> >> Signed-off-by: Shiju Jose >> --- >> drivers/cxl/core/mbox.c | 53 >+++++++++++++++++++++++++++++++++++++++++ >> drivers/cxl/cxlmem.h | 28 ++++++++++++++++++++++ >> 2 files changed, 81 insertions(+) >> >> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index >> 82e279b821e2..999965871048 100644 >> --- a/drivers/cxl/core/mbox.c >> +++ b/drivers/cxl/core/mbox.c >> @@ -1318,6 +1318,59 @@ int cxl_get_supported_features(struct >> cxl_memdev_state *mds, } >> EXPORT_SYMBOL_NS_GPL(cxl_get_supported_features, CXL); >> >> +size_t cxl_get_feature(struct cxl_memdev_state *mds, >> + const uuid_t feat_uuid, void *feat_out, >> + size_t feat_out_size, >> + size_t feat_out_min_size, >> + enum cxl_get_feat_selection selection) { >> + struct cxl_dev_state *cxlds =3D &mds->cxlds; >> + struct cxl_mbox_get_feat_in pi; >> + struct cxl_mbox_cmd mbox_cmd; >> + size_t data_rcvd_size =3D 0; >> + size_t data_to_rd_size, size_out; >> + int rc; >> + >> + if (feat_out_size < feat_out_min_size) { >> + dev_err(cxlds->dev, >> + "%s: feature out buffer size(%lu) is not big enough\n", >> + __func__, feat_out_size); >> + return 0; >> + } >> + >> + if (feat_out_size <=3D mds->payload_size) >> + size_out =3D feat_out_size; >> + else >> + size_out =3D mds->payload_size; > >Using min() instead? > size_out =3D min(feat_out_size, mds->payload_size) Will do. > >> + pi.uuid =3D feat_uuid; >> + pi.selection =3D selection; >> + do { >> + if ((feat_out_min_size - data_rcvd_size) <=3D mds->payload_size) >> + data_to_rd_size =3D feat_out_min_size - data_rcvd_size; >> + else >> + data_to_rd_size =3D mds->payload_size; > >data_to_rd_size =3D min(feat_out_min_size - data_rcvd_size, mds->payload_s= ize); Will do. > >It seems feat_out_min_size is always the same as feat_out_size in this ser= ies, >what is it for? For the loop here, my understanding is we need to fill up = the out >buffer multiple times if the feature cannot be held in a call, so it seems >feat_out_min_size should be feat_out_size here. feat_out_size and feat_out_min_size added separately because this function = is a common interface and it might be useful for the features like DDR5 ECS Control, where the = Get feature output payload size is relatively high and actually required data is small, contains DDR5 = ECS control feature readable attributes for N number of memory media FRUs. > >Fan > >> + >> + pi.offset =3D cpu_to_le16(data_rcvd_size); >> + pi.count =3D cpu_to_le16(data_to_rd_size); >> + >> + mbox_cmd =3D (struct cxl_mbox_cmd) { >> + .opcode =3D CXL_MBOX_OP_GET_FEATURE, >> + .size_in =3D sizeof(pi), >> + .payload_in =3D &pi, >> + .size_out =3D size_out, >> + .payload_out =3D feat_out + data_rcvd_size, >> + .min_out =3D data_to_rd_size, >> + }; >> + rc =3D cxl_internal_send_cmd(mds, &mbox_cmd); >> + if (rc < 0 || mbox_cmd.size_out =3D=3D 0) >> + return 0; >> + data_rcvd_size +=3D mbox_cmd.size_out; >> + } while (data_rcvd_size < feat_out_min_size); >> + >> + return data_rcvd_size; >> +} >> +EXPORT_SYMBOL_NS_GPL(cxl_get_feature, CXL); >> + >> int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len, >> struct cxl_region *cxlr) >> { >> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index >> 06231e63373e..c822eb30e6d1 100644 >> --- a/drivers/cxl/cxlmem.h >> +++ b/drivers/cxl/cxlmem.h >> @@ -528,6 +528,7 @@ enum cxl_opcode { >> CXL_MBOX_OP_GET_SUPPORTED_LOGS =3D 0x0400, >> CXL_MBOX_OP_GET_LOG =3D 0x0401, >> CXL_MBOX_OP_GET_SUPPORTED_FEATURES =3D 0x0500, >> + CXL_MBOX_OP_GET_FEATURE =3D 0x0501, >> CXL_MBOX_OP_IDENTIFY =3D 0x4000, >> CXL_MBOX_OP_GET_PARTITION_INFO =3D 0x4100, >> CXL_MBOX_OP_SET_PARTITION_INFO =3D 0x4101, >> @@ -754,6 +755,28 @@ struct cxl_mbox_get_supp_feats_out { >> struct cxl_mbox_supp_feat_entry feat_entries[]; } __packed; >> >> +/* >> + * Get Feature CXL 3.1 Spec 8.2.9.6.2 */ >> + >> +/* >> + * Get Feature input payload >> + * CXL rev 3.1 section 8.2.9.6.2 Table 8-99 */ enum >> +cxl_get_feat_selection { >> + CXL_GET_FEAT_SEL_CURRENT_VALUE, >> + CXL_GET_FEAT_SEL_DEFAULT_VALUE, >> + CXL_GET_FEAT_SEL_SAVED_VALUE, >> + CXL_GET_FEAT_SEL_MAX >> +}; >> + >> +struct cxl_mbox_get_feat_in { >> + uuid_t uuid; >> + __le16 offset; >> + __le16 count; >> + u8 selection; >> +} __packed; >> + >> /* Get Poison List CXL 3.0 Spec 8.2.9.8.4.1 */ struct >> cxl_mbox_poison_in { >> __le64 offset; >> @@ -888,6 +911,11 @@ int cxl_set_timestamp(struct cxl_memdev_state >> *mds); int cxl_get_supported_features(struct cxl_memdev_state *mds, >> u32 count, u16 start_index, >> struct cxl_mbox_get_supp_feats_out *feats_out); >> +size_t cxl_get_feature(struct cxl_memdev_state *mds, >> + const uuid_t feat_uuid, void *feat_out, >> + size_t feat_out_size, >> + size_t feat_out_min_size, >> + enum cxl_get_feat_selection selection); >> int cxl_poison_state_init(struct cxl_memdev_state *mds); int >> cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len, >> struct cxl_region *cxlr); >> -- >> 2.34.1 >> Thanks, Shiju