Re: [PATCH 5/5] arm/arm64: smccc: Add ARCH_SOC_ID support

[John Garry]

On 30/04/2020 12:48, Sudeep Holla wrote:
+static int __init smccc_soc_init(void)
+{
+       struct device *dev;
+       int ret, soc_id_rev;
+       struct arm_smccc_res res;
+       static char soc_id_str[8], soc_id_rev_str[12];
+
+       if (arm_smccc_get_version() < ARM_SMCCC_VERSION_1_2)
+               return 0;
+
+       ret = smccc_soc_id_support_check();
+       if (ret)
+               return ret;
+
+       arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 0, &res);
+
+       ret = smccc_map_error_codes(res.a0);
+       if (ret)
+               return ret;
+
+       soc_id_version = res.a0;
+
+       arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 1, &res);
+
+       ret = smccc_map_error_codes(res.a0);
+       if (ret)
+               return ret;
+
+       soc_id_rev = res.a0;
+
+       soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+       if (!soc_dev_attr)
+               return -ENOMEM;
+
+       sprintf(soc_id_str, "0x%04x", IMP_DEF_SOC_ID(soc_id_version));
+       sprintf(soc_id_rev_str, "0x%08x", soc_id_rev);
+
+       soc_dev_attr->soc_id = soc_id_str;
+       soc_dev_attr->revision = soc_id_rev_str;
+
+       soc_dev = soc_device_register(soc_dev_attr);
+       if (IS_ERR(soc_dev)) {
+               ret = PTR_ERR(soc_dev);
+               goto free_soc;
+       }
+
+       dev = soc_device_to_device(soc_dev);
+

Just wondering, what about if the platform already had a SoC driver - 
now it could have another one, such that we may have multiple sysfs soc 
devices, right?

Thanks,
John

+       ret = devm_device_add_groups(dev, jep106_id_groups);
+       if (ret) {
+               dev_err(dev, "sysfs create failed: %d\n", ret);
+               goto unregister_soc;
+       }
+
+       pr_info("SMCCC SoC ID: %s Revision %s\n", soc_dev_attr->soc_id,
+               soc_dev_attr->revision);
+
+       return 0;