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Message-Id: <20210731204845.21196-2-andre.przywara@arm.com>
Date: Sat, 31 Jul 2021 21:48:44 +0100
From: Andre Przywara <andre.przywara@....com>
To: Matt Mackall <mpm@...enic.com>,
Herbert Xu <herbert@...dor.apana.org.au>,
Mark Rutland <mark.rutland@....com>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Sudeep Holla <sudeep.holla@....com>
Cc: linux-crypto@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Ard Biesheuvel <ardb@...nel.org>,
Mark Brown <broonie@...nel.org>, Will Deacon <will@...nel.org>,
Ali Saidi <alisaidi@...zon.com>,
Jon Nettleton <jon@...id-run.com>
Subject: [PATCH v4 1/2] firmware: smccc: Register smccc_trng platform device
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@....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
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