Re: [PATCH v2] UIO: Implement a UIO interface for the SMX Cryptengine

["Hans-Jürgen Koch" <hjk@linutronix.de>]

Am Wed, 12 Mar 2008 21:06:22 +1100
schrieb Ben Nizette <bn@niasdigital.com>:

> This patch implements a UIO interface for the SMX Cryptengine.
> 
> The Cryptengine found on the Nias Digital SMX board is best suited
> for a UIO interface.  It is not wired in to the cryptographic API
> as the engine handles it's own keys, algorithms, everything.  All
> that we know about is that if there's room in the buffer, you can
> write data to it and when there's data ready, you read it out again.
> 
> There isn't necessarily even any direct correlation between data
> going in and data coming out again, the engine may consume or
> generate data all on its own.
> 
> This driver is for proprietary hardware but we're always told to
> submit the drivers anyway; here you are.  :-)
> 
> This is version 2 of this patch and addresses all issues raised by
> Hans-Jürgen Koch in his review of version 1.

But it doesn't address the issue Paul Mundt has raised. As this driver will
probably serve as an example for other UIO platform drivers, it should be
correct. And I also consider it a bit impolite if you completely ignore Paul,
who has taken the time to review your driver and pointed out a mistake. His
solution is obviously the correct one.

Thanks,
Hans

> 
> Signed-off-by: Ben Nizette <bn@niasdigital.com>
> ---
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 2cdb591..480fd44 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -3554,6 +3554,11 @@ M:	mhoffman@lightlink.com
>  L:	lm-sensors@lm-sensors.org
>  S:	Maintained
>  
> +SMX UIO Interface
> +P:	Ben Nizette
> +M:	bn@niasdigital.com
> +S:	Maintained
> +
>  SOFTMAC LAYER (IEEE 802.11)
>  P:	Daniel Drake
>  M:	dsd@gentoo.org
> diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
> index b778ed7..f57b347 100644
> --- a/drivers/uio/Kconfig
> +++ b/drivers/uio/Kconfig
> @@ -26,4 +26,16 @@ config UIO_CIF
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called uio_cif.
>  
> +config UIO_SMX
> +	tristate "SMX cryptengine UIO interface"
> +	depends on UIO
> +	default n
> +	help
> +	  Userspace IO interface to the Cryptography engine found on the
> +	  Nias Digital SMX boards.  These will be available from Q4 2008
> +	  from http://www.niasdigital.com.  The userspace part of this
> +	  driver will be released under the GPL at the same time as the
> +	  hardware and will be able to be downloaded from the same site.
> +
> +	  If you compile this as a module, it will be called uio_smx.
>  endmenu
> diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
> index 7fecfb4..18c4566 100644
> --- a/drivers/uio/Makefile
> +++ b/drivers/uio/Makefile
> @@ -1,2 +1,3 @@
>  obj-$(CONFIG_UIO)	+= uio.o
>  obj-$(CONFIG_UIO_CIF)	+= uio_cif.o
> +obj-$(CONFIG_UIO_SMX)	+= uio_smx.o
> diff --git a/drivers/uio/uio_smx.c b/drivers/uio/uio_smx.c
> new file mode 100644
> index 0000000..6a8bb6e
> --- /dev/null
> +++ b/drivers/uio/uio_smx.c
> @@ -0,0 +1,118 @@
> +/*
> + * UIO SMX Cryptengine driver.
> + *
> + * (C) 2008 Nias Digital P/L <bn@niasdigital.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/uio_driver.h>
> +
> +#include <asm/io.h>
> +
> +#define SMX_CSR  0x00000000
> +#define SMX_EnD  0x00000001
> +#define SMX_RUN  0x00000002
> +#define SMX_DRDY 0x00000004
> +#define SMX_ERR  0x00000008
> +
> +static irqreturn_t smx_handler(int irq, struct uio_info *dev_info)
> +{
> +	void __iomem *csr = dev_info->mem[0].internal_addr + SMX_CSR;
> +
> +	u32 status = ioread32(csr);
> +
> +	if (!csr & SMX_DRDY)
> +		return IRQ_NONE;
> +
> +	/* Disable interrupt */
> +	iowrite32(status & ~SMX_DRDY, csr);
> +	return IRQ_HANDLED;
> +}
> +
> +static int __devinit smx_ce_probe(struct platform_device *dev)
> +{
> +	struct uio_info *info;
> +	struct resource *regs;
> +
> +	info = kzalloc(sizeof(struct uio_info), GFP_KERNEL);
> +	if (!info)
> +		return -ENOMEM;
> +
> +	regs = platform_get_resource(dev, IORESOURCE_MEM, 0);
> +	if (!regs)
> +		goto out_free;
> +
> +	info->mem[0].addr = regs->start;
> +	if (!info->mem[0].addr)
> +		goto out_free;
> +	info->mem[0].internal_addr = ioremap(regs->start,
> +					     regs->end - regs->start);
> +	if (!info->mem[0].internal_addr)
> +		goto out_free;
> +
> +	info->mem[0].size = regs->end - regs->start;
> +	info->mem[0].memtype = UIO_MEM_PHYS;
> +
> +	info->name = "smx-ce";
> +	info->version = "0.03";
> +	info->irq = platform_get_irq(dev, 0);
> +	info->irq_flags = IRQF_SHARED;
> +	info->handler = smx_handler;
> +
> +	platform_set_drvdata(dev, info);
> +
> +	if (uio_register_device(&dev->dev, info))
> +		goto out_unmap;
> +
> +	return 0;
> +out_unmap:
> +	iounmap(info->mem[0].internal_addr);
> +out_free:
> +	kfree(info);
> +
> +	return -ENODEV;
> +}
> +
> +static int __devexit smx_ce_remove(struct platform_device *dev)
> +{
> +	struct uio_info *info = platform_get_drvdata(dev);
> +
> +	uio_unregister_device(info);
> +	platform_set_drvdata(dev, NULL);
> +	iounmap(info->mem[0].internal_addr);
> +
> +	kfree(info);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver smx_ce_driver = {
> +	.probe		= smx_ce_probe,
> +	.remove		= __devexit_p(smx_ce_remove),
> +	.driver		= {
> +		.name	= "smx-ce",
> +		.owner	= THIS_MODULE,
> +	},
> +};
> +
> +static int __init smx_ce_init_module(void)
> +{
> +	return platform_driver_register(&smx_ce_driver);
> +}
> +module_init(smx_ce_init_module);
> +
> +static void __exit smx_ce_exit_module(void)
> +{
> +	platform_driver_unregister(&smx_ce_driver);
> +}
> +module_exit(smx_ce_exit_module);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Ben Nizette <bn@niasdigital.com>");