On Tue, 2011-06-21 at 08:19 -0400, Josh Boyer wrote:
> Various PowerPC 4xx SoCs contain a TRNG embedded in the Security function.
> This adds a device driver for that TRNG.
> 
> Signed-off-by: Josh Boyer <jwbo...@linux.vnet.ibm.com>

Looks good.

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

> ---
>  drivers/char/hw_random/Kconfig      |   12 +++
>  drivers/char/hw_random/Makefile     |    1 +
>  drivers/char/hw_random/ppc4xx-rng.c |  156 
> +++++++++++++++++++++++++++++++++++
>  3 files changed, 169 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/char/hw_random/ppc4xx-rng.c
> 
> diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
> index a60043b..1d2ebc7 100644
> --- a/drivers/char/hw_random/Kconfig
> +++ b/drivers/char/hw_random/Kconfig
> @@ -210,3 +210,15 @@ config HW_RANDOM_PICOXCELL
>         module will be called picoxcell-rng.
>  
>         If unsure, say Y.
> +
> +config HW_RANDOM_PPC4XX
> +     tristate "PowerPC 4xx generic true random number generator support"
> +     depends on HW_RANDOM && PPC && 4xx
> +     ---help---
> +      This driver provides the kernel-side support for the TRNG hardware
> +      found in the security function of some PowerPC 4xx SoCs.
> +
> +      To compile this driver as a module, choose M here: the
> +      module will be called ppc4xx-rng.
> +
> +      If unsure, say N.
> diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
> index 3db4eb8..c88f244 100644
> --- a/drivers/char/hw_random/Makefile
> +++ b/drivers/char/hw_random/Makefile
> @@ -20,3 +20,4 @@ obj-$(CONFIG_HW_RANDOM_MXC_RNGA) += mxc-rnga.o
>  obj-$(CONFIG_HW_RANDOM_OCTEON) += octeon-rng.o
>  obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
>  obj-$(CONFIG_HW_RANDOM_PICOXCELL) += picoxcell-rng.o
> +obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o
> diff --git a/drivers/char/hw_random/ppc4xx-rng.c 
> b/drivers/char/hw_random/ppc4xx-rng.c
> new file mode 100644
> index 0000000..b8afa6a
> --- /dev/null
> +++ b/drivers/char/hw_random/ppc4xx-rng.c
> @@ -0,0 +1,156 @@
> +/*
> + * Generic PowerPC 44x RNG driver
> + *
> + * Copyright 2011 IBM Corporation
> + *
> + * 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; version 2 of the License.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +#include <linux/hw_random.h>
> +#include <linux/delay.h>
> +#include <linux/of_platform.h>
> +#include <asm/io.h>
> +
> +#define PPC4XX_TRNG_DEV_CTRL 0x60080
> +
> +#define PPC4XX_TRNGE 0x00020000
> +#define PPC4XX_TRNG_CTRL 0x0008
> +#define PPC4XX_TRNG_CTRL_DALM 0x20
> +#define PPC4XX_TRNG_STAT 0x0004
> +#define PPC4XX_TRNG_STAT_B 0x1
> +#define PPC4XX_TRNG_DATA 0x0000
> +
> +#define MODULE_NAME "ppc4xx_rng"
> +
> +static int ppc4xx_rng_data_present(struct hwrng *rng, int wait)
> +{
> +     void __iomem *rng_regs = (void __iomem *) rng->priv;
> +     int busy, i, present = 0;
> +
> +     for (i = 0; i < 20; i++) {
> +             busy = (in_le32(rng_regs + PPC4XX_TRNG_STAT) & 
> PPC4XX_TRNG_STAT_B);
> +             if (!busy || !wait) {
> +                     present = 1;
> +                     break;
> +             }
> +             udelay(10);
> +     }
> +     return present;
> +}
> +
> +static int ppc4xx_rng_data_read(struct hwrng *rng, u32 *data)
> +{
> +     void __iomem *rng_regs = (void __iomem *) rng->priv;
> +     *data = in_le32(rng_regs + PPC4XX_TRNG_DATA);
> +     return 4;
> +}
> +
> +static int ppc4xx_rng_enable(int enable)
> +{
> +     struct device_node *ctrl;
> +     void __iomem *ctrl_reg;
> +     int err = 0;
> +     u32 val;
> +
> +     /* Find the main crypto device node and map it to turn the TRNG on */
> +     ctrl = of_find_compatible_node(NULL, NULL, "amcc,ppc4xx-crypto");
> +     if (!ctrl)
> +             return -ENODEV;
> +
> +     ctrl_reg = of_iomap(ctrl, 0);
> +     if (!ctrl_reg) {
> +             err = -ENODEV;
> +             goto out;
> +     }
> +
> +     val = in_le32(ctrl_reg + PPC4XX_TRNG_DEV_CTRL);
> +
> +     if (enable)
> +             val |= PPC4XX_TRNGE;
> +     else
> +             val = val & ~PPC4XX_TRNGE;
> +
> +     out_le32(ctrl_reg + PPC4XX_TRNG_DEV_CTRL, val);
> +     iounmap(ctrl_reg);
> +
> +out:
> +     of_node_put(ctrl);
> +
> +     return err;
> +}
> +
> +static struct hwrng ppc4xx_rng = {
> +     .name = MODULE_NAME,
> +     .data_present = ppc4xx_rng_data_present,
> +     .data_read = ppc4xx_rng_data_read,
> +};
> +
> +static int __devinit ppc4xx_rng_probe(struct platform_device *dev)
> +{
> +     void __iomem *rng_regs;
> +     int err = 0;
> +
> +     rng_regs = of_iomap(dev->dev.of_node, 0);
> +     if (!rng_regs)
> +             return -ENODEV;
> +
> +     err = ppc4xx_rng_enable(1);
> +     if (err)
> +             return err;
> +
> +     out_le32(rng_regs + PPC4XX_TRNG_CTRL, PPC4XX_TRNG_CTRL_DALM);
> +     ppc4xx_rng.priv = (unsigned long) rng_regs;
> +
> +     err = hwrng_register(&ppc4xx_rng);
> +
> +     return err;
> +}
> +
> +static int __devexit ppc4xx_rng_remove(struct platform_device *dev)
> +{
> +     void __iomem *rng_regs = (void __iomem *) ppc4xx_rng.priv;
> +
> +     hwrng_unregister(&ppc4xx_rng);
> +     ppc4xx_rng_enable(0);
> +     iounmap(rng_regs);
> +
> +     return 0;
> +}
> +
> +static struct of_device_id ppc4xx_rng_match[] = {
> +     { .compatible = "ppc4xx-rng", },
> +     { .compatible = "amcc,ppc460ex-rng", },
> +     { .compatible = "amcc,ppc440epx-rng", },
> +     {},
> +};
> +
> +static struct platform_driver ppc4xx_rng_driver = {
> +     .driver = {
> +             .name = MODULE_NAME,
> +             .owner = THIS_MODULE,
> +             .of_match_table = ppc4xx_rng_match,
> +     },
> +     .probe = ppc4xx_rng_probe,
> +     .remove = ppc4xx_rng_remove,
> +};
> +
> +static int __init ppc4xx_rng_init(void)
> +{
> +     return platform_driver_register(&ppc4xx_rng_driver);
> +}
> +module_init(ppc4xx_rng_init);
> +
> +static void __exit ppc4xx_rng_exit(void)
> +{
> +     platform_driver_unregister(&ppc4xx_rng_driver);
> +}
> +module_exit(ppc4xx_rng_exit);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Josh Boyer <jwbo...@linux.vnet.ibm.com>");
> +MODULE_DESCRIPTION("HW RNG driver for PPC 4xx processors");


-- 
Mathematics is the supreme nostalgia of our time.


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