UIO: Implement a UIO interface for the SMX Cryptengine

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 4 of this patch and addresses all issues raised by
Hans-Jürgen Koch and Paul Mundt in their reviews.  Slightly altered
is Paul's suggestion to use DRV_NAME and DRV_VERSION as the UIO
version and name.  While at the moment they are the same, there
is no reason for them to stay that way.  Nevertheless we now at
least provide a MODULE_VERSION macro to keep modinfo happy.

Signed-off-by: Ben Nizette <[email protected]>
Acked-by: Paul Mundt <[email protected]>
Signed-off-by: Hans J Koch <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

MAINTAINERS

@@ -3604,6 +3604,11 @@ M:	[email protected]
 L:	[email protected]
 S:	Maintained
 
+SMX UIO Interface
+P:	Ben Nizette
+M:	[email protected]
+S:	Maintained
+
 SOFTWARE RAID (Multiple Disks) SUPPORT
 P:	Ingo Molnar
 M:	[email protected]

drivers/uio/Kconfig

@@ -26,4 +26,17 @@ 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.
+
 endif

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

drivers/uio/uio_smx.c

@@ -0,0 +1,140 @@
+/*
+ * UIO SMX Cryptengine driver.
+ *
+ * (C) 2008 Nias Digital P/L <[email protected]>
+ *
+ * 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 <linux/io.h>
+
+#define DRV_NAME "smx-ce"
+#define DRV_VERSION "0.03"
+
+#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 (!(status & 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)
+{
+
+	int ret = -ENODEV;
+	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) {
+		dev_err(&dev->dev, "No memory resource specified\n");
+		goto out_free;
+	}
+
+	info->mem[0].addr = regs->start;
+	if (!info->mem[0].addr) {
+		dev_err(&dev->dev, "Invalid memory resource\n");
+		goto out_free;
+	}
+
+	info->mem[0].size = regs->end - regs->start + 1;
+	info->mem[0].internal_addr = ioremap(regs->start, info->mem[0].size);
+
+	if (!info->mem[0].internal_addr) {
+		dev_err(&dev->dev, "Can't remap memory address range\n");
+		goto out_free;
+	}
+
+	info->mem[0].memtype = UIO_MEM_PHYS;
+
+	info->name = "smx-ce";
+	info->version = "0.03";
+
+	info->irq = platform_get_irq(dev, 0);
+	if (info->irq < 0) {
+		ret = info->irq;
+		dev_err(&dev->dev, "No (or invalid) IRQ resource specified\n");
+		goto out_unmap;
+	}
+
+	info->irq_flags = IRQF_SHARED;
+	info->handler = smx_handler;
+
+	platform_set_drvdata(dev, info);
+
+	ret = uio_register_device(&dev->dev, info);
+
+	if (ret)
+		goto out_unmap;
+
+	return 0;
+
+out_unmap:
+	iounmap(info->mem[0].internal_addr);
+out_free:
+	kfree(info);
+
+	return ret;
+}
+
+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	= DRV_NAME,
+		.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_VERSION(DRV_VERSION);
+MODULE_AUTHOR("Ben Nizette <[email protected]>");