| Message ID | 20210224082230.29015-3-noltari@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | hwrng: bcm2835: add reset support | expand |
Hi Philipp, > El 3 mar 2021, a las 14:52, Philipp Zabel <p.zabel@pengutronix.de> escribió: > > Hi Álvaro, > > On Wed, 2021-02-24 at 09:22 +0100, Álvaro Fernández Rojas wrote: > [...] >> @@ -115,6 +121,8 @@ static void bcm2835_rng_cleanup(struct hwrng *rng) >> /* disable rng hardware */ >> rng_writel(priv, 0, RNG_CTRL); >> >> + reset_control_rearm(priv->reset); >> + >> if (!IS_ERR(priv->clk)) >> clk_disable_unprepare(priv->clk); >> } >> @@ -159,6 +167,10 @@ static int bcm2835_rng_probe(struct platform_device *pdev) >> if (PTR_ERR(priv->clk) == -EPROBE_DEFER) >> return -EPROBE_DEFER; >> >> + priv->reset = devm_reset_control_get_optional_exclusive(dev, NULL); >> + if (IS_ERR(priv->reset)) >> + return PTR_ERR(priv->reset); >> + >> priv->rng.name = pdev->name; >> priv->rng.init = bcm2835_rng_init; >> priv->rng.read = bcm2835_rng_read; > > That doesn't seem right. reset_control_rearm() doesn't do anything if > the reset control is exclusive. Either the reset control should be > requested as shared, or the _rearm should be removed. In only added reset_control_rearm() because Florian requested it… I think it’s not needed, so we can use v3, since it was the only change between v3 and v4... > > regards > Philipp Best regards, Álvaro.
On 3/3/21 6:06 AM, Álvaro Fernández Rojas wrote: > Hi Philipp, > >> El 3 mar 2021, a las 14:52, Philipp Zabel <p.zabel@pengutronix.de> escribió: >> >> Hi Álvaro, >> >> On Wed, 2021-02-24 at 09:22 +0100, Álvaro Fernández Rojas wrote: >> [...] >>> @@ -115,6 +121,8 @@ static void bcm2835_rng_cleanup(struct hwrng *rng) >>> /* disable rng hardware */ >>> rng_writel(priv, 0, RNG_CTRL); >>> >>> + reset_control_rearm(priv->reset); >>> + >>> if (!IS_ERR(priv->clk)) >>> clk_disable_unprepare(priv->clk); >>> } >>> @@ -159,6 +167,10 @@ static int bcm2835_rng_probe(struct platform_device *pdev) >>> if (PTR_ERR(priv->clk) == -EPROBE_DEFER) >>> return -EPROBE_DEFER; >>> >>> + priv->reset = devm_reset_control_get_optional_exclusive(dev, NULL); >>> + if (IS_ERR(priv->reset)) >>> + return PTR_ERR(priv->reset); >>> + >>> priv->rng.name = pdev->name; >>> priv->rng.init = bcm2835_rng_init; >>> priv->rng.read = bcm2835_rng_read; >> >> That doesn't seem right. reset_control_rearm() doesn't do anything if >> the reset control is exclusive. Either the reset control should be >> requested as shared, or the _rearm should be removed. > > In only added reset_control_rearm() because Florian requested it… > I think it’s not needed, so we can use v3, since it was the only change between v3 and v4... Not the first time I am confused by the reset API not sure if I will ever get it one day, so apologies for suggesting something incorrect here. -- Florian
diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c index 1a7c43b43c6b..92658edaff22 100644 --- a/drivers/char/hw_random/bcm2835-rng.c +++ b/drivers/char/hw_random/bcm2835-rng.c @@ -13,6 +13,7 @@ #include <linux/platform_device.h> #include <linux/printk.h> #include <linux/clk.h> +#include <linux/reset.h> #define RNG_CTRL 0x0 #define RNG_STATUS 0x4 @@ -32,6 +33,7 @@ struct bcm2835_rng_priv { void __iomem *base; bool mask_interrupts; struct clk *clk; + struct reset_control *reset; }; static inline struct bcm2835_rng_priv *to_rng_priv(struct hwrng *rng) @@ -94,6 +96,10 @@ static int bcm2835_rng_init(struct hwrng *rng) return ret; } + ret = reset_control_reset(priv->reset); + if (ret) + return ret; + if (priv->mask_interrupts) { /* mask the interrupt */ val = rng_readl(priv, RNG_INT_MASK); @@ -115,6 +121,8 @@ static void bcm2835_rng_cleanup(struct hwrng *rng) /* disable rng hardware */ rng_writel(priv, 0, RNG_CTRL); + reset_control_rearm(priv->reset); + if (!IS_ERR(priv->clk)) clk_disable_unprepare(priv->clk); } @@ -159,6 +167,10 @@ static int bcm2835_rng_probe(struct platform_device *pdev) if (PTR_ERR(priv->clk) == -EPROBE_DEFER) return -EPROBE_DEFER; + priv->reset = devm_reset_control_get_optional_exclusive(dev, NULL); + if (IS_ERR(priv->reset)) + return PTR_ERR(priv->reset); + priv->rng.name = pdev->name; priv->rng.init = bcm2835_rng_init; priv->rng.read = bcm2835_rng_read;
BCM6368 devices need to reset the in order to generate true random numbers. This is what BCM6368 produces without a reset: root@OpenWrt:/# cat /dev/hwrng | rngtest -c 1000 rngtest 6.10 Copyright (c) 2004 by Henrique de Moraes Holschuh This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. rngtest: starting FIPS tests... rngtest: bits received from input: 20000032 rngtest: FIPS 140-2 successes: 0 rngtest: FIPS 140-2 failures: 1000 rngtest: FIPS 140-2(2001-10-10) Monobit: 2 rngtest: FIPS 140-2(2001-10-10) Poker: 1000 rngtest: FIPS 140-2(2001-10-10) Runs: 1000 rngtest: FIPS 140-2(2001-10-10) Long run: 30 rngtest: FIPS 140-2(2001-10-10) Continuous run: 0 rngtest: input channel speed: (min=37.253; avg=320.827; max=635.783)Mibits/s rngtest: FIPS tests speed: (min=12.141; avg=15.034; max=16.428)Mibits/s rngtest: Program run time: 1336176 microseconds Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com> --- v4: add reset_control_rearm(). v3: no changes. v2: no changes. drivers/char/hw_random/bcm2835-rng.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)