Introduce invocation helper functions for driver that interact with firmware supporting Arm SMCCC v1.0 specification based on existing arm_smccc_1_1_*() helpers. The new functions suit device where secure world supports SMCCC v1.0 but not v1.1.
This change allows devices to ensure consistency of the conduit used among drivers defining a conduit method as at runtime all devices are expected to use the very same SMCCC invocation conduit.
Signed-off-by: Etienne Carriere etienne.carriere@linaro.org --- drivers/firmware/Makefile | 1 + drivers/firmware/arm_smccc_conduit.c | 147 +++++++++++++++++++++++++++ include/linux/arm-smccc.h | 106 +++++++++++++++++++ 3 files changed, 254 insertions(+) create mode 100644 drivers/firmware/arm_smccc_conduit.c
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile index e9fb838af4df..5a4a72a06346 100644 --- a/drivers/firmware/Makefile +++ b/drivers/firmware/Makefile @@ -5,6 +5,7 @@ obj-$(CONFIG_ARM_SCPI_PROTOCOL) += arm_scpi.o obj-$(CONFIG_ARM_SCPI_POWER_DOMAIN) += scpi_pm_domain.o obj-$(CONFIG_ARM_SDE_INTERFACE) += arm_sdei.o +obj-$(CONFIG_HAVE_ARM_SMCCC) += arm_smccc_conduit.o obj-$(CONFIG_DMI) += dmi_scan.o obj-$(CONFIG_DMI_SYSFS) += dmi-sysfs.o obj-$(CONFIG_EDD) += edd.o diff --git a/drivers/firmware/arm_smccc_conduit.c b/drivers/firmware/arm_smccc_conduit.c new file mode 100644 index 000000000000..37b90e92a4b3 --- /dev/null +++ b/drivers/firmware/arm_smccc_conduit.c @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2020, Linaro Limited + */ + +#include <linux/arm-smccc.h> +#include <linux/device.h> +#include <linux/of.h> + +static enum arm_smccc_conduit arm_smccc_1_0_conduit = SMCCC_CONDUIT_NONE; + +/* Helpers for nice trace when called outside a device instance */ +#define PRINT_INFO(dev, ...) \ + do { \ + if (dev) \ + dev_info(dev, __VA_ARGS__); \ + else \ + pr_info(__VA_ARGS__); \ + } while (0) + +#define PRINT_WARN(dev, ...) \ + do { \ + if (dev) \ + dev_warn(dev, __VA_ARGS__); \ + else \ + pr_warn(__VA_ARGS__); \ + } while (0) + +#define PRINT_ERROR(dev, ...) \ + do { \ + if (dev) \ + dev_err(dev, __VA_ARGS__); \ + else \ + pr_err(__VA_ARGS__); \ + } while (0) + +static const char *conduit_str(enum arm_smccc_conduit conduit) +{ + static const char hvc_str[] = "HVC"; + static const char smc_str[] = "SMC"; + static const char unknown[] = "unknown"; + + switch (conduit) { + case SMCCC_CONDUIT_HVC: + return hvc_str; + case SMCCC_CONDUIT_SMC: + return smc_str; + default: + return unknown; + } +} + +static int set_conduit(struct device *dev, enum arm_smccc_conduit conduit) +{ + switch (conduit) { + case SMCCC_CONDUIT_HVC: + case SMCCC_CONDUIT_SMC: + break; + default: + return -EINVAL; + } + + if (arm_smccc_1_0_conduit == SMCCC_CONDUIT_NONE) { + arm_smccc_1_0_conduit = conduit; + return 0; + } + + if (conduit == arm_smccc_1_0_conduit) + return 0; + + PRINT_ERROR(dev, "inconsistent conduits %u (%s) vs %u (%s)\n", + conduit, conduit_str(conduit), + arm_smccc_1_0_conduit, conduit_str(arm_smccc_1_0_conduit)); + + return -EINVAL; +} + +static enum arm_smccc_conduit method_to_conduit(const char *method) +{ + if (!strcmp("hvc", method)) + return SMCCC_CONDUIT_HVC; + else if (!strcmp("smc", method)) + return SMCCC_CONDUIT_SMC; + else + return SMCCC_CONDUIT_NONE; +} + +static int set_conduit_from_node(struct device *dev, struct device_node *np) +{ + const char *method; + + PRINT_INFO(dev, "probing for conduit method from DT.\n"); + + if (!np) + return -EINVAL; + + if (!of_property_read_string(np, "method", &method)) { + enum arm_smccc_conduit dev_conduit = method_to_conduit(method); + + if (dev_conduit == SMCCC_CONDUIT_NONE) { + PRINT_WARN(dev, "invalid "method" property "%s"\n", + method); + return -EINVAL; + } + + return set_conduit(dev, dev_conduit); + } + + if (arm_smccc_1_0_conduit != SMCCC_CONDUIT_NONE) + return 0; + + PRINT_WARN(dev, "missing "method" property\n"); + return -ENXIO; +} + +int devm_arm_smccc_1_0_set_conduit(struct device *dev) +{ + if (!dev || !dev->of_node) + return -EINVAL; + + return set_conduit_from_node(dev, dev->of_node); +} +EXPORT_SYMBOL_GPL(devm_arm_smccc_1_0_set_conduit); + +int of_arm_smccc_1_0_set_conduit(struct device_node *np) +{ + if (!np) + return -EINVAL; + + return set_conduit_from_node(NULL, np); +} +EXPORT_SYMBOL_GPL(of_arm_smccc_1_0_set_conduit); + +int arm_smccc_1_0_set_conduit(enum arm_smccc_conduit conduit) +{ + if (set_conduit(NULL, conduit)) + return -EINVAL; + + return 0; +} +EXPORT_SYMBOL_GPL(arm_smccc_1_0_set_conduit); + +enum arm_smccc_conduit arm_smccc_1_0_get_conduit(void) +{ + return arm_smccc_1_0_conduit; +} +EXPORT_SYMBOL_GPL(arm_smccc_1_0_get_conduit); diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index 59494df0f55b..4f5f17b00a6b 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -377,5 +377,111 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned long a1, ARM_SMCCC_OWNER_STANDARD_HYP, \ 0x21)
+/* SMCCC v1.0 compliant invocation helpers */ + +/* + * Like arm_smccc_1_0* but always returns SMCCC_RET_NOT_SUPPORTED. + * Used when the SMCCC conduit is not defined. The empty asm statement + * avoids compiler warnings about unused variables. + */ +#define __fail_smccc_1_0(...) \ + do { \ + __declare_args(7, __VA_ARGS__); \ + asm ("" __constraints(7)); \ + ___res->a0 = SMCCC_RET_NOT_SUPPORTED; \ + } while (0) + +/* + * arm_smccc_1_0_invoke() - make an SMCCC v1.0 compliant call + * + * This is a macro taking eight source arguments and an return structure. + * It uses the SMCCC conduit registered during driver(s) initialization. + * + * @a0-a7: arguments passed in registers 0 to 7 + * @res: result values from registers 0 to 3 + * + * This macro will make either an HVC call or an SMC call depending on the + * specified SMCCC conduit. If no valid conduit is available then -1 + * (SMCCC_RET_NOT_SUPPORTED) is returned in @res.a0. + * + * The return value provides the conduit that was used. + */ +#define arm_smccc_1_0_invoke(...) ({ \ + enum arm_smccc_conduit conduit = arm_smccc_1_0_get_conduit(); \ + switch (conduit) { \ + case SMCCC_CONDUIT_HVC: \ + arm_smccc_hvc(__VA_ARGS__); \ + break; \ + case SMCCC_CONDUIT_SMC: \ + arm_smccc_smc(__VA_ARGS__); \ + break; \ + default: \ + __fail_smccc_1_0(__VA_ARGS__); \ + conduit = SMCCC_CONDUIT_NONE; \ + } \ + conduit; \ + }) + +struct device; +struct device_node; + +#ifdef CONFIG_HAVE_ARM_SMCCC +/** + * arm_smccc_1_0_get_conduit() - Return registered SMCCC conduit + */ +enum arm_smccc_conduit arm_smccc_1_0_get_conduit(void); + +/** + * arm_smccc_1_0_set_conduit - Register SMCCC invocation conduit + * @conduit: conduit to register + * + * Return 0 on success and -EINVAL on failure. + */ +int arm_smccc_1_0_set_conduit(enum arm_smccc_conduit); + +/** + * devm_arm_smccc_1_0_set_conduit() - Set SMCCC v1.0 conduit if found in device + * @dev: Device instance + * + * Set the SMCCC invocation conduit based on device node if it has a "methhod" + * property that defines the SMCCC conduit to be used. If it has not, check a + * conduit is already registered. + * + * Return 0 on success, -ENXIO if no conduit found, -EINVAL otherwise. + */ +int devm_arm_smccc_1_0_set_conduit(struct device *dev); + +/** + * of_arm_smccc_1_0_set_conduit() - Set SMCCC v1.0 conduit if found in FDT node + * @np: Node instance + * + * Set the SMCCC invocation conduit based on device node if it has a "methhod" + * property that defines the SMCCC conduit to be used. If it has not, check a + * conduit is already registered. + * + * Return 0 on success, -ENXIO if no conduit found, -EINVAL otherwise. + */ +int of_arm_smccc_1_0_set_conduit(struct device_node *np); +#else +static inline enum arm_smccc_conduit arm_smccc_1_0_get_conduit(void) +{ + return SMCCC_CONDUIT_NONE; +} + +static inline int arm_smccc_1_0_set_conduit(enum arm_smccc_conduit); +{ + return -EINVAL; +} + +static inline int devm_arm_smccc_1_0_set_conduit(struct device *dev); +{ + return -EINVAL; +} + +static inline int of_arm_smccc_1_0_set_conduit(struct device_node *np); +{ + return -EINVAL; +} +#endif /* CONFIG_HAVE_ARM_SMCCC */ #endif /*__ASSEMBLY__*/ #endif /*__LINUX_ARM_SMCCC_H*/