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Mon, 30 Oct 2023 21:31:56 GMT Received: from hu-eberman-lv.qualcomm.com (10.49.16.6) by nasanex01b.na.qualcomm.com (10.46.141.250) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.39; Mon, 30 Oct 2023 14:31:55 -0700 From: Elliot Berman Date: Mon, 30 Oct 2023 14:31:34 -0700 Subject: [PATCH RFC 2/2] firmware: psci: Read and use vendor reset types MIME-Version: 1.0 Message-ID: <20231030-arm-psci-system_reset2-vendor-reboots-v1-2-dcdd63352ad1@quicinc.com> References: <20231030-arm-psci-system_reset2-vendor-reboots-v1-0-dcdd63352ad1@quicinc.com> In-Reply-To: <20231030-arm-psci-system_reset2-vendor-reboots-v1-0-dcdd63352ad1@quicinc.com> To: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Lorenzo Pieralisi , Mark Rutland CC: Satya Durga Srinivasu Prabhala , Melody Olvera , , , , Florian Fainelli , Elliot Berman X-Mailer: b4 0.13-dev X-Originating-IP: [10.49.16.6] X-ClientProxiedBy: nalasex01b.na.qualcomm.com (10.47.209.197) To nasanex01b.na.qualcomm.com (10.46.141.250) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: nPoM-AxfQC_BuKVQzcAwanO9tqVyCc2T X-Proofpoint-GUID: nPoM-AxfQC_BuKVQzcAwanO9tqVyCc2T X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.987,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-10-30_13,2023-10-27_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 bulkscore=0 mlxscore=0 adultscore=0 mlxlogscore=999 spamscore=0 phishscore=0 clxscore=1015 suspectscore=0 lowpriorityscore=0 malwarescore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2310240000 definitions=main-2310300168 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231030_143209_831487_F0C2229E X-CRM114-Status: GOOD ( 28.83 ) 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 SoC vendors have different types of resets and are controlled through various registers. For instance, Qualcomm chipsets can reboot to a "download mode" that allows a RAM dump to be collected. Another example is they also support writing a cookie that can be read by bootloader during next boot. PSCI offers a mechanism, SYSTEM_RESET2, for these vendor reset types to be implemented without requiring drivers for every register/cookie. Add support in PSCI to statically map reboot mode commands from userspace to a vendor reset and cookie value using the device tree. Reboot mode framework is close but doesn't quite fit with the design and requirements for PSCI SYSTEM_RESET2. Some of these issues can be solved but doesn't seem reasonable in sum: 1. reboot mode registers against the reboot_notifier_list, which is too early to call SYSTEM_RESET2. PSCI would need to remember the reset type from the reboot-mode framework callback and use it psci_sys_reset. 2. reboot mode assumes only one cookie/parameter is described in the device tree. SYSTEM_RESET2 uses 2: one for the type and one for cookie. 3. psci cpuidle driver already registers a driver against the arm,psci-1.0 compatible. Refactoring would be needed to have both a cpuidle and reboot-mode driver. Signed-off-by: Elliot Berman --- drivers/firmware/psci/psci.c | 87 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 86 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c index d9629ff87861..93914b48a950 100644 --- a/drivers/firmware/psci/psci.c +++ b/drivers/firmware/psci/psci.c @@ -29,6 +29,8 @@ #include #include +#define REBOOT_PREFIX "reboot-mode-" + /* * While a 64-bit OS can make calls with SMC32 calling conventions, for some * calls it is necessary to use SMC64 to pass or return 64-bit values. @@ -79,6 +81,14 @@ struct psci_0_1_function_ids get_psci_0_1_function_ids(void) static u32 psci_cpu_suspend_feature; static bool psci_system_reset2_supported; +struct psci_reset_param { + const char *mode; + u32 reset_type; + u32 cookie; +}; +static struct psci_reset_param *psci_reset_params; +static size_t num_psci_reset_params; + static inline bool psci_has_ext_power_state(void) { return psci_cpu_suspend_feature & @@ -305,11 +315,29 @@ static int get_set_conduit_method(const struct device_node *np) return 0; } +static void psci_vendor_sys_reset2(unsigned long action, void *data) +{ + const char *cmd = data; + size_t i; + + for (i = 0; i < num_psci_reset_params; i++) { + if (!strcmp(psci_reset_params[i].mode, cmd)) { + invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), + psci_reset_params[i].reset_type, + psci_reset_params[i].cookie, 0); + break; + } + } +} + static int psci_sys_reset(struct notifier_block *nb, unsigned long action, void *data) { + if (psci_system_reset2_supported && num_psci_reset_params) + psci_vendor_sys_reset2(action, data); + if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) && - psci_system_reset2_supported) { + psci_system_reset2_supported) { /* * reset_type[31] = 0 (architectural) * reset_type[30:0] = 0 (SYSTEM_WARM_RESET) @@ -748,6 +776,63 @@ static const struct of_device_id psci_of_match[] __initconst = { {}, }; +static int __init psci_init_system_reset2_modes(void) +{ + const size_t len = strlen(REBOOT_PREFIX); + struct psci_reset_param *param; + struct device_node *np; + struct property *prop; + size_t count = 0; + u32 magic[2]; + int ret; + + if (!psci_system_reset2_supported) + return 0; + + np = of_find_matching_node(NULL, psci_of_match); + if (!np) + return 0; + + for_each_property_of_node(np, prop) { + if (strncmp(prop->name, REBOOT_PREFIX, len)) + continue; + ret = of_property_count_elems_of_size(np, prop->name, sizeof(magic[0])); + if (ret != 1 && ret != 2) + continue; + + count++; + } + + param = psci_reset_params = kcalloc(count, sizeof(*psci_reset_params), GFP_KERNEL); + if (!psci_reset_params) + return -ENOMEM; + + for_each_property_of_node(np, prop) { + if (strncmp(prop->name, REBOOT_PREFIX, len)) + continue; + + param->mode = kstrdup_const(prop->name + len, GFP_KERNEL); + if (!param->mode) + continue; + + ret = of_property_read_variable_u32_array(np, prop->name, magic, 1, 2); + if (ret < 0) { + pr_warn("Failed to parse vendor reboot mode %s\n", param->mode); + kfree(param->mode); + continue; + } + + /* Force reset type to be in vendor space */ + param->reset_type = PSCI_1_1_RESET_TYPE_VENDOR_START | magic[0]; + param->cookie = ret == 2 ? magic[1] : 0; + param++; + num_psci_reset_params++; + } + + return 0; +} +arch_initcall(psci_init_system_reset2_modes); + int __init psci_dt_init(void) { struct device_node *np;