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path: root/drivers/char/hw_random/stm32-rng.c
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2023-12-15hwrng: stm32 - Convert to platform remove callback returning voidUwe Kleine-König
The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is ignored (apart from emitting a warning) and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new(), which already returns void. Eventually after all drivers are converted, .remove_new() will be renamed to .remove(). Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-12-08hwrng: stm32 - add missing clk_disable_unprepare() in stm32_rng_init()Yang Yingliang
Add clk_disable_unprepare() in the error path in stm32_rng_init(). Fixes: 6b85a7e141cb ("hwrng: stm32 - implement STM32MP13x support") Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Reviewed-by: Gatien Chevallier <gatien.chevallier@foss.st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-01hwrng: stm32 - rework power management sequencesGatien Chevallier
Implement stm32_rng_suspend()/stm32_rng_resume() low-power APIs called when the hardware block context will be lost. There is no need to save the RNG_CR register in stm32_rng_runtime_suspend() as the context is not lost. Therefore, only enable/disable the RNG in the runtime sequences. Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-01hwrng: stm32 - support RNG configuration locking mechanismGatien Chevallier
If "st,rng-lock-conf" DT binding property is set for a stm32-rng node, the RNG configuration will be locked until next hardware block reset or platform reset. Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-01hwrng: stm32 - restrain RNG noise source clockGatien Chevallier
For NIST certification the noise source sampling may need to be restrained. This change implements an algorithm that gets the rate of the RNG clock and apply the correct value in CLKDIV field in RNG_CR register to force the RNG clock rate to be "max_clock_rate" maximum. As it is platform-specific, implement it as a compat data. Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-01hwrng: stm32 - rework error handling in stm32_rng_read()Gatien Chevallier
Try to conceal seed errors when possible. If, despite the error concealing tries, a seed error is still present, then return an error. A clock error does not compromise the hardware block and data can still be read from RNG_DR. Just warn that the RNG clock is too slow and clear RNG_SR. Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-01hwrng: stm32 - implement error concealmentGatien Chevallier
The RNG driver should be capable of recovering from an error. Implement an error concealment API. This avoids irrecoverable RNG state. Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-01hwrng: stm32 - implement STM32MP13x supportGatien Chevallier
The RNG present on STM32MP13x platforms introduces a customizable configuration and the conditional reset. STM32 RNG configuration should best fit the requirements of the platform. Therefore, put a platform-specific RNG configuration field in the platform data. Default RNG configuration for STM32MP13 is the NIST certified configuration [1]. While there, fix and the RNG init sequence to support all RNG versions. [1] https://csrc.nist.gov/projects/cryptographic-module-validation-program/entropy-validations/certificate/53 Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-01hwrng: stm32 - use devm_platform_get_and_ioremap_resource() APIGatien Chevallier
Use devm_platform_get_and_ioremap_resource() to get and ioremap a resource. Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-08-04hwrng: Explicitly include correct DT includesRob Herring
The DT of_device.h and of_platform.h date back to the separate of_platform_bus_type before it was merged into the regular platform bus. As part of that merge prepping Arm DT support 13 years ago, they "temporarily" include each other. They also include platform_device.h and of.h. As a result, there's a pretty much random mix of those include files used throughout the tree. In order to detangle these headers and replace the implicit includes with struct declarations, users need to explicitly include the correct includes. Signed-off-by: Rob Herring <robh@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-11-18hwrng: stm32 - rename readl return valueTomas Marek
Use a more meaningful name for the readl return value variable. Link: https://lore.kernel.org/all/Y1J3QwynPFIlfrIv@loth.rohan.me.apana.org.au/ Signed-off-by: Tomas Marek <tomas.marek@elrest.cz> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-10-21hwrng: stm32 - fix read of the last wordTomas Marek
The stm32_rng_read() function samples TRNG by 4 bytes until at least 5 bytes are free in the input buffer. The last four bytes are never read. For example, 60 bytes are returned in case the input buffer size is 64 bytes. Read until at least 4 bytes are free in the input buffer. Fill the buffer entirely in case the buffer size is divisible by 4. Cc: Oleg Karfich <oleg.karfich@wago.com> Signed-off-by: Tomas Marek <tomas.marek@elrest.cz> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-10-21hwrng: stm32 - fix number of returned bytes on readTomas Marek
The stm32_rng_read() function uses `retval` variable as a counter of generated random bytes. However, the same variable is used to store a result of the polling function in case the driver is waiting until the TRNG is ready. The TRNG generates random numbers by 16B. One loop read 4B. So, the function calls the polling every 16B, i.e. every 4th loop. The `retval` counter is reset on poll call and only number of bytes read after the last poll call is returned to the caller. The remaining sampled random bytes (for example 48 out of 64 in case 64 bytes are read) are not used. Use different variable to store the polling function result and do not overwrite `retval` counter. Cc: Oleg Karfich <oleg.karfich@wago.com> Signed-off-by: Tomas Marek <tomas.marek@elrest.cz> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-10-02hwrng: stm32 - use semicolons rather than commas to separate statementsJulia Lawall
Replace commas with semicolons. What is done is essentially described by the following Coccinelle semantic patch (http://coccinelle.lip6.fr/): // <smpl> @@ expression e1,e2; @@ e1 -, +; e2 ... when any // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-05-24treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 110Thomas Gleixner
Based on 1 normalized pattern(s): this file is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this file is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190523091650.284757242@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-15hwrng: stm32 - set default random qualityLionel Debieve
Add a default quality to hw_random device to be automatically set as new default entropy. Setting random quality will decrease the crng init time by switching to this hardware random source. Signed-off-by: Lionel Debieve <lionel.debieve@st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-04-15hwrng: stm32 - fix unbalanced pm_runtime_enableLionel Debieve
No remove function implemented yet in the driver. Without remove function, the pm_runtime implementation complains when removing and probing again the driver. Signed-off-by: Lionel Debieve <lionel.debieve@st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-05-05hwrng: stm32 - fix pm_suspend issuelionel.debieve@st.com
When suspend is called after pm_runtime_suspend, same callback is used and access to rng register is freezing system. By calling the pm_runtime_force_suspend, it first checks that runtime has been already done. Signed-off-by: Lionel Debieve <lionel.debieve@st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-03-03hwrng: stm32 - rework read timeout calculationlionel.debieve@st.com
Increase timeout delay to support longer timing linked to rng initialization. Measurement is based on timer instead of instructions per iteration which is not powerful on all targets. Signed-off-by: Lionel Debieve <lionel.debieve@st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-03-03hwrng: stm32 - allow disable clock error detectionlionel.debieve@st.com
Add a new property that allow to disable the clock error detection which is required when the clock source selected is out of specification (which is not mandatory). Signed-off-by: Lionel Debieve <lionel.debieve@st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-03-03hwrng: stm32 - add reset during probelionel.debieve@st.com
Avoid issue when probing the RNG without reset if bad status has been detected previously Signed-off-by: Lionel Debieve <lionel.debieve@st.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-05-31hwrng: stm32 - fix maybe uninitialized variable warningMaxime Coquelin
This patch fixes the following warning: drivers/char/hw_random/stm32-rng.c: In function 'stm32_rng_read': drivers/char/hw_random/stm32-rng.c:82:19: warning: 'sr' may be used uninitialized in this function Reported-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> Suggested-by: Arnd Bergmann <arnd@arndb.de> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-10-15hwrng: stm32 - Fix build with CONFIG_PMDaniel Thompson
Commit c6a97c42e399 ("hwrng: stm32 - add support for STM32 HW RNG") was inadequately tested (actually it was tested quite hard so incompetent would be a better description that inadequate) and does not compile on platforms with CONFIG_PM set. Fix this. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-10-14hwrng: stm32 - add support for STM32 HW RNGDaniel Thompson
Add support for STMicroelectronics STM32 random number generator. The config value defaults to N, reflecting the fact that STM32 is a very low resource microcontroller platform and unlikely to be targeted by any "grown up" defconfigs. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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