[PATCH v4 1/2] firmware: smccc: Register smccc_trng platform device
From: Andre Przywara <andre.przywara@arm.com>
Date: 2021-07-31 20:49:38
Also in:
linux-arm-kernel, lkml
Subsystem:
secure monitor call(smc) calling convention (smccc), the rest · Maintainers:
Mark Rutland, Lorenzo Pieralisi, Sudeep Holla, Linus Torvalds
At the moment we probe for the Random Number Generator SMCCC service, and use that in the core code (arch_get_random). However the hardware entropy can also be useful to access from userland, and be it to assess its quality. Register a platform device when the SMCCC TRNG service is detected, to allow a hw_random driver to hook onto this. The function registering the device is deliberately made in a way which allows expansion, so other services that could be exposed via a platform device (or some other interface), can be added here easily. Signed-off-by: Andre Przywara <andre.przywara@arm.com> --- drivers/firmware/smccc/smccc.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c
index 9f937b125ab0..60ccf3e90d7d 100644
--- a/drivers/firmware/smccc/smccc.c
+++ b/drivers/firmware/smccc/smccc.c@@ -9,6 +9,7 @@ #include <linux/init.h> #include <linux/arm-smccc.h> #include <linux/kernel.h> +#include <linux/platform_device.h> #include <asm/archrandom.h> static u32 smccc_version = ARM_SMCCC_VERSION_1_0;
@@ -42,3 +43,19 @@ u32 arm_smccc_get_version(void) return smccc_version; } EXPORT_SYMBOL_GPL(arm_smccc_get_version); + +static int __init smccc_devices_init(void) +{ + struct platform_device *pdev; + + if (smccc_trng_available) { + pdev = platform_device_register_simple("smccc_trng", -1, + NULL, 0); + if (IS_ERR(pdev)) + pr_err("smccc_trng: could not register device: %ld\n", + PTR_ERR(pdev)); + } + + return 0; +} +device_initcall(smccc_devices_init);
--
2.17.6