Re: [PATCH] Use AB3100 MFD core IRQ for interrupt randomness

Matt Mackall
2010-01-11T22:48:01Z

On Sat, 2010-01-09 at 01:38 +0100, Linus Walleij wrote:
> This reintroduces the entropy sampling of the AB3100 IRQ as the
> IRQF_SAMPLE_RANDOM is going out according to the feature removal
> schedule. I'm trying to do this the right way then, so CC:ing some
> random people for a quick review. We add entropy for interrupt
> events in the AB3100 which are truly random in nature, like
> external cables being connected, voltages on batteries dropping
> below certain ranges, ADC triggers or overheating.
>
> Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
> Cc: Robin Getz <rgetz@blackfin.uclinux.org>
> Cc: Matt Mackall <mpm@selenic.com>
> ---
> drivers/mfd/ab3100-core.c | 17 +++++++++--------
> 1 files changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mfd/ab3100-core.c b/drivers/mfd/ab3100-core.c
> index aa3824a..a2ce3b6 100644
> --- a/drivers/mfd/ab3100-core.c
> +++ b/drivers/mfd/ab3100-core.c
> @@ -1,5 +1,5 @@
> /*
> - * Copyright (C) 2007-2009 ST-Ericsson
> + * Copyright (C) 2007-2010 ST-Ericsson
> * License terms: GNU General Public License (GPL) version 2
> * Low-level core for exclusive access to the AB3100 IC on the I2C bus
> * and some basic chip-configuration.
> @@ -14,6 +14,7 @@
> #include <linux/platform_device.h>
> #include <linux/device.h>
> #include <linux/interrupt.h>
> +#include <linux/random.h>
> #include <linux/debugfs.h>
> #include <linux/seq_file.h>
> #include <linux/uaccess.h>
> @@ -376,6 +377,8 @@ static irqreturn_t ab3100_irq_handler(int irq, void *data)
> u32 fatevent;
> int err;
>
> + add_interrupt_randomness(irq);
> +
> err = ab3100_get_register_page_interruptible(ab3100, AB3100_EVENTA1,
> event_regs, 3);
> if (err)
> @@ -720,10 +723,7 @@ static struct platform_device ab3100_##devname##_device = { \
> .id = -1, \
> }
>
> -/*
> - * This lists all the subdevices and corresponding register
> - * ranges.
> - */
> +/* This lists all the subdevices */
> AB3100_DEVICE(dac, "ab3100-dac");
> AB3100_DEVICE(leds, "ab3100-leds");
> AB3100_DEVICE(power, "ab3100-power");
> @@ -889,10 +889,11 @@ static int __init ab3100_probe(struct i2c_client *client,
> if (err)
> goto exit_no_setup;
>
> - /* This real unpredictable IRQ is of course sampled for entropy */
> err = request_threaded_irq(client->irq, NULL, ab3100_irq_handler,
> - IRQF_ONESHOT,
> - "ab3100-core", ab3100);
> + IRQF_ONESHOT, "ab3100-core", ab3100);
> + /* This real unpredictable IRQ is of course sampled for entropy */
> + rand_initialize_irq(client->irq);
> +
> if (err)
> goto exit_no_irq;

Acked-by: Matt Mackall <mpm@selenic.com>

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