Messages in this thread | | | Date | Wed, 27 Jun 2012 12:07:03 +0100 | From | Jamie Iles <> | Subject | Re: [PATCH v2] Exynos : Add support for Exynos random number generator |
| |
Hi Jongwha,
Just minor nits.
On Wed, Jun 27, 2012 at 07:31:01PM +0900, Jonghwa Lee wrote: > diff --git a/drivers/char/hw_random/Kconfig > b/drivers/char/hw_random/Kconfig > index f45dad3..a9e3806 100644 > --- a/drivers/char/hw_random/Kconfig > +++ b/drivers/char/hw_random/Kconfig > @@ -263,3 +263,15 @@ config HW_RANDOM_PSERIES > module will be called pseries-rng. > > If unsure, say Y. > + > +config HW_RANDOM_EXYNOS > + tristate "EXYNOS HW random number generator support" > + depends on HW_RANDOM && ARCH_EXYNOS && HAS_IOMEM && PM_RUNTIME
I don't think this needs an ARCH_EXYNOS dependency does it? I think you do need a dependency on HAVE_CLK though then it can be built for other platforms.
> diff --git a/drivers/char/hw_random/exynos-rng.c > b/drivers/char/hw_random/exynos-rng.c > new file mode 100644 > index 0000000..9c8d690 > --- /dev/null > +++ b/drivers/char/hw_random/exynos-rng.c > @@ -0,0 +1,191 @@ > +/* > + * exynos-rng.c - Random Number Generator driver for the exynos > + * > + * Copyright (C) 2012 Samsung Electronics > + * Jonghwa Lee <jonghwa3.lee@smasung.com> > + * > + * This program 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; > + * > + * This program 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. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, write to the Free Software > + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA > + * > + */ > + > +#include <linux/hw_random.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/delay.h> > +#include <linux/io.h> > +#include <linux/platform_device.h> > +#include <linux/clk.h> > +#include <linux/pm_runtime.h> > +#include <linux/err.h> > + > +#define EXYNOS_PRNG_STATUS_OFFSET 0x10 > +#define EXYNOS_PRNG_SEED_OFFSET 0x140 > +#define EXYNOS_PRNG_OUT1_OFFSET 0x160 > +#define SEED_SETTING_DONE BIT(1) > +#define PRNG_START 0x18 > +#define PRNG_DONE BIT(5) > + > +struct exynos_rng { > + struct device *dev; > + struct hwrng rng; > + void __iomem *mem; > + struct clk *clk; > +}; > + > +static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset) > +{ > + return __raw_readl(rng->mem + offset); > +} > + > +static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset) > +{ > + __raw_writel(val, rng->mem + offset); > +} > + > +static int exynos_init(struct hwrng *rng) > +{ > + struct exynos_rng *exynos_rng = container_of(rng, > + struct exynos_rng, rng); > + int i; > + int ret = 0; > + > + pm_runtime_get_sync(exynos_rng->dev); > + > + for (i = 0 ; i < 5 ; i++) > + exynos_rng_writel(exynos_rng, i, EXYNOS_PRNG_SEED_OFFSET + 4*i); > + > + if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET) > + & SEED_SETTING_DONE)) > + ret = -EIO; > + > + pm_runtime_put_noidle(exynos_rng->dev); > + > + return ret; > +} > + > +static int exynos_read(struct hwrng *rng, void *buf, > + size_t max, bool wait) > +{ > + struct exynos_rng *exynos_rng = container_of(rng, > + struct exynos_rng, rng); > + u32 *data = buf; > + > + pm_runtime_get_sync(exynos_rng->dev); > + > + exynos_rng_writel(exynos_rng, PRNG_START, 0); > + > + do { > + cpu_relax(); > + } while (!(exynos_rng_readl(exynos_rng, > + EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE));
A minor nit, but
while (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE)) cpu_relax();
would be a bit more conventional.
> + > + exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET); > + > + *data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET); > + > + pm_runtime_put(exynos_rng->dev); > + return 4; > +} > + > +static int __devinit exynos_rng_probe(struct platform_device *pdev) > +{ > + int ret; > + struct exynos_rng *exynos_rng; > + struct resource *res; > + > + exynos_rng = devm_kzalloc(&pdev->dev, sizeof(struct exynos_rng), > + GFP_KERNEL); > + if (!exynos_rng) > + return -ENOMEM; > + > + exynos_rng->dev = &pdev->dev; > + exynos_rng->rng.name = "exynos"; > + exynos_rng->rng.init = exynos_init; > + exynos_rng->rng.read = exynos_read; > + exynos_rng->clk = devm_clk_get(&pdev->dev, "secss"); > + if (IS_ERR(exynos_rng->clk)) { > + dev_err(&pdev->dev, "Couldn't get clock.\n"); > + return -ENOENT; > + } > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + if (!res) { > + clk_put(exynos_rng->clk);
Doesn't the devm_clk_get() above handle this for you?
Otherwise looks good to me!
Jamie
| |