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Thu, 20 Aug 2026 12:48:58 -0700 (PDT) X-Received: by 2002:a05:620a:4014:b0:936:8840:427f with SMTP id af79cd13be357-937395429e3mr52930085a.4.1787255338126; Thu, 20 Aug 2026 12:48:58 -0700 (PDT) Received: from shalem ([2001:1c00:c32:7800:5bfa:a036:83f0:f9ec]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c2459198ec5sm113433266b.34.2026.08.20.12.48.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Aug 2026 12:48:56 -0700 (PDT) From: Hans de Goede To: Bjorn Andersson , Cristian Marussi , Sudeep Holla Cc: Hans de Goede , Daniel Lezcano , arm-scmi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, imx@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH v3 2/3] firmware: arm_scmi: Pre-register protocol, name tupples for standard protocols Date: Thu, 20 Aug 2026 21:48:49 +0200 Message-ID: <20260820194850.459739-3-johannes.goede@oss.qualcomm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820194850.459739-1-johannes.goede@oss.qualcomm.com> References: <20260820194850.459739-1-johannes.goede@oss.qualcomm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Authority-Analysis: v=2.4 cv=GPM41ONK c=1 sm=1 tr=0 ts=6a875a2b cx=c_pps a=qKBjSQ1v91RyAK45QCPf5w==:117 a=xqWC_Br6kY4A:10 a=Sv0fKeRqtYgA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=Um2Pa8k9VHT-vaBCBUpS:22 a=bC-a23v3AAAA:8 a=7CQSdrXTAAAA:8 a=EUspDBNiAAAA:8 a=VscC1fOeZKh3OTZq1J8A:9 a=NFOGd7dJGGMPyQGDc5-O:22 a=FO4_E8m0qiDe52t0p3_H:22 a=a-qgeE7W1pNrGK8U0ZQC:22 X-Proofpoint-ORIG-GUID: 3XhEd0gjiK3rSV3FTBLZ6RWp8m3pSH4- X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODIwMDE0OSBTYWx0ZWRfX7A79OEWjZ++y a02HyMyLZc5nWgtwuC0gXBM20eOf3HN2kFSYGhoEVYU5Vrvi3i38/hv5tlVuDOq287Tlud9594y 2GgdZAaJYdkyAN+eH7mLW5BY+kZ/qt970UNek5ArJWRBo9ffafKu+FZZQRDQ258X4mt8Et7oWs5 kjXlCv6N09gdtg4Sl8W4iA4ZZZnDhKCaEGXYrLYskMOUdzLAkEb3YvBVzOghrfYj/13uvTOOPGx 7+CI6vsIO/Q+OwFbrXD25EbwsWN3CpuQ/9T9Qvsm3ZL/ODOQb4MP0WpUbj2/KpVxNjnPI2LPkVq CBKCUESfXDZp4RWSEe63lBOmquIsErdtX/x28tz1mjysGGNy6j9JP5Rpwhk3Rb1GnBP+LMTXk8p tRBXlH6fT/czSTC3s23zCAd8yjASXz5ndcARuti1N5nHny9UAlQW44YLC6ILxpz4oJiJxJux8+o jWjn/ixgIJFfJ5I+Icg== X-Proofpoint-GUID: 3XhEd0gjiK3rSV3FTBLZ6RWp8m3pSH4- X-Proofpoint-Spam-Info: AW1haW4tMjYwODIwMDE0OSBTYWx0ZWRfX/uNbUXlGLwTm 1w7oO3HdQbgPFMO/HPZiQiKsUoSRLWS8UmB74q0QXpYrqkgeIINKBCn+Y5omAd+NBe4KtCnY3tL bnV1leOHdmW47ctYqXszLHrwnurOOtA= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-20_01,2026-08-20_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 priorityscore=1501 spamscore=0 clxscore=1015 impostorscore=0 lowpriorityscore=0 suspectscore=0 phishscore=0 malwarescore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608200149 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260820_124900_225010_E2D8682C X-CRM114-Status: GOOD ( 20.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Cristian Marussi Driver module auto-loading requires the devices to already be created for udev to get the necessary uevents based on which udev auto-loads modules. But SCMI devices are only created after their { protocol, name } tupples have been registered which is done from scmi_driver_register(). This creates a circular dependency where device creation is waiting for the driver to register and loading the module with the driver is waiting for the device to be created. Pre-register the tupples for standard protocols to break this circular dependency. Tested-by: Hans de Goede Signed-off-by: Cristian Marussi Signed-off-by: Hans de Goede --- Changes in v3: - Drop adding of a bus uevent function this is already done - Update comments and commit message with a better explanation of why - Link to v1/RFC: https://patch.msgid.link/20250203100154.140877-2-cristian.marussi@arm.com --- drivers/firmware/arm_scmi/bus.c | 47 ++++++++++++++++++++++++++++----- 1 file changed, 40 insertions(+), 7 deletions(-) diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c index d12d5de15a1a..111727904a89 100644 --- a/drivers/firmware/arm_scmi/bus.c +++ b/drivers/firmware/arm_scmi/bus.c @@ -77,12 +77,13 @@ static int scmi_protocol_device_request(const struct scmi_device_id *id_table) if (phead) { head = phead; list_for_each_entry(rdev, head, node) { + /* pr_debug() because dups are expected for std protocols */ if (!strcmp(rdev->id_table->name, id_table->name)) { - pr_err("Ignoring duplicate request [%d] %s\n", - rdev->id_table->protocol_id, - rdev->id_table->name); - ret = -EINVAL; - goto out; + pr_debug("Device already requested [%d] %s\n", + rdev->id_table->protocol_id, + rdev->id_table->name); + mutex_unlock(&scmi_requested_devices_mtx); + return 0; } } } @@ -579,17 +580,49 @@ static void scmi_devices_unregister(void) bus_for_each_dev(&scmi_bus_type, NULL, NULL, __scmi_devices_unregister); } +/* Standard protocols table */ +static const struct scmi_device_id scmi_std_id_table[] = { + { SCMI_PROTOCOL_POWER, "genpd" }, + { SCMI_PROTOCOL_SYSTEM, "syspower" }, + { SCMI_PROTOCOL_PERF, "perf" }, + { SCMI_PROTOCOL_PERF, "cpufreq" }, + { SCMI_PROTOCOL_CLOCK, "clocks" }, + { SCMI_PROTOCOL_SENSOR, "hwmon" }, + { SCMI_PROTOCOL_SENSOR, "iiodev" }, + { SCMI_PROTOCOL_RESET, "reset" }, + { SCMI_PROTOCOL_VOLTAGE, "regulator" }, + { SCMI_PROTOCOL_POWERCAP, "powercap" }, + { SCMI_PROTOCOL_PINCTRL, "pinctrl" }, + { SCMI_PROTOCOL_PINCTRL, "pinctrl-imx" }, + { }, +}; + static int __init scmi_bus_init(void) { int retval; retval = bus_register(&scmi_bus_type); - if (retval) + if (retval) { pr_err("SCMI protocol bus register failed (%d)\n", retval); + return retval; + } + + /* + * Driver module auto-loading requires the devices to already be created + * for udev to get the necessary uevents. But the devices are only + * created after their { protocol, name } tupples have been registered + * which is done from scmi_driver_register(). Pre-register the tupples + * for known (in tree) drivers to break this circular dependency. + */ + retval = scmi_protocol_table_register(scmi_std_id_table); + if (retval) { + bus_unregister(&scmi_bus_type); + return retval; + } pr_info("SCMI protocol bus registered\n"); - return retval; + return 0; } subsys_initcall(scmi_bus_init); -- 2.55.0