char/pcmcia: add scr24x_cs chip card interface driver

This implements only the very basic protocol "Mode A", just to make the
device functional. Patches to implement "Mode C" that uses better bulking
and is interrupt-driver may follow.

The device essentially speaks the same protocol as USB CCID devices do over
the bulk endpoints. The driver exchanges the command submissions and
responses over a plain read()/write() interface, compatible with legacy
OpenCT's pcmcia_block driver.

Patches for the newer CCID driver are available:
https://github.com/lkundrak/CCID/tree/lr/pcmcia_block

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MAINTAINERS

@@ -10699,6 +10699,11 @@ W:	http://www.sunplus.com
 S:	Supported
 F:	arch/score/
 
+SCR24X CHIP CARD INTERFACE DRIVER
+M:	Lubomir Rintel <lkundrak@v3.sk>
+S:	Supported
+F:	drivers/char/pcmcia/scr24x_cs.c
+
 SYSTEM CONTROL & POWER INTERFACE (SCPI) Message Protocol drivers
 M:	Sudeep Holla <sudeep.holla@arm.com>
 L:	linux-arm-kernel@lists.infradead.org

drivers/char/pcmcia/Kconfig

@@ -43,6 +43,17 @@ config CARDMAN_4040
 	  (http://www.omnikey.com/), or a current development version of OpenCT
 	  (http://www.opensc-project.org/opensc).
 
+config SCR24X
+	tristate "SCR24x Chip Card Interface support"
+	depends on PCMCIA
+	help
+	  Enable support for the SCR24x PCMCIA Chip Card Interface.
+
+	  To compile this driver as a module, choose M here.
+	  The module will be called scr24x_cs..
+
+	  If unsure say N.
+
 config IPWIRELESS
 	tristate "IPWireless 3G UMTS PCMCIA card support"
 	depends on PCMCIA && NETDEVICES && TTY

drivers/char/pcmcia/Makefile

@@ -7,3 +7,4 @@
 obj-$(CONFIG_SYNCLINK_CS) += synclink_cs.o
 obj-$(CONFIG_CARDMAN_4000) += cm4000_cs.o
 obj-$(CONFIG_CARDMAN_4040) += cm4040_cs.o
+obj-$(CONFIG_SCR24X) += scr24x_cs.o

drivers/char/pcmcia/scr24x_cs.c

@@ -0,0 +1,372 @@
+/*
+ * SCR24x PCMCIA Smart Card Reader Driver
+ *
+ * Copyright (C) 2005-2006 TL Sudheendran
+ * Copyright (C) 2016 Lubomir Rintel
+ *
+ * Derived from "scr24x_v4.2.6_Release.tar.gz" driver by TL Sudheendran.
+ *
+ * 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; either version 2, or (at your option)
+ * any later version.
+ *
+ * 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; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/cdev.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+
+#include <pcmcia/cistpl.h>
+#include <pcmcia/ds.h>
+
+#define CCID_HEADER_SIZE	10
+#define CCID_LENGTH_OFFSET	1
+#define CCID_MAX_LEN		271
+
+#define SCR24X_DATA(n)		(1 + n)
+#define SCR24X_CMD_STATUS	7
+#define CMD_START		0x40
+#define CMD_WRITE_BYTE		0x41
+#define CMD_READ_BYTE		0x42
+#define STATUS_BUSY		0x80
+
+struct scr24x_dev {
+	struct device *dev;
+	struct cdev c_dev;
+	unsigned char buf[CCID_MAX_LEN];
+	int devno;
+	struct mutex lock;
+	struct kref refcnt;
+	u8 __iomem *regs;
+};
+
+#define SCR24X_DEVS 8
+static DECLARE_BITMAP(scr24x_minors, SCR24X_DEVS);
+
+static struct class *scr24x_class;
+static dev_t scr24x_devt;
+
+static void scr24x_delete(struct kref *kref)
+{
+	struct scr24x_dev *dev = container_of(kref, struct scr24x_dev,
+								refcnt);
+
+	kfree(dev);
+}
+
+static int scr24x_wait_ready(struct scr24x_dev *dev)
+{
+	u_char status;
+	int timeout = 100;
+
+	do {
+		status = ioread8(dev->regs + SCR24X_CMD_STATUS);
+		if (!(status & STATUS_BUSY))
+			return 0;
+
+		msleep(20);
+	} while (--timeout);
+
+	return -EIO;
+}
+
+static int scr24x_open(struct inode *inode, struct file *filp)
+{
+	struct scr24x_dev *dev = container_of(inode->i_cdev,
+				struct scr24x_dev, c_dev);
+
+	kref_get(&dev->refcnt);
+	filp->private_data = dev;
+
+	return nonseekable_open(inode, filp);
+}
+
+static int scr24x_release(struct inode *inode, struct file *filp)
+{
+	struct scr24x_dev *dev = filp->private_data;
+
+	/* We must not take the dev->lock here as scr24x_delete()
+	 * might be called to remove the dev structure altogether.
+	 * We don't need the lock anyway, since after the reference
+	 * acquired in probe() is released in remove() the chrdev
+	 * is already unregistered and noone can possibly acquire
+	 * a reference via open() anymore. */
+	kref_put(&dev->refcnt, scr24x_delete);
+	return 0;
+}
+
+static int read_chunk(struct scr24x_dev *dev, size_t offset, size_t limit)
+{
+	size_t i, y;
+	int ret;
+
+	for (i = offset; i < limit; i += 5) {
+		iowrite8(CMD_READ_BYTE, dev->regs + SCR24X_CMD_STATUS);
+		ret = scr24x_wait_ready(dev);
+		if (ret < 0)
+			return ret;
+
+		for (y = 0; y < 5 && i + y < limit; y++)
+			dev->buf[i + y] = ioread8(dev->regs + SCR24X_DATA(y));
+	}
+
+	return 0;
+}
+
+static ssize_t scr24x_read(struct file *filp, char __user *buf, size_t count,
+								loff_t *ppos)
+{
+	struct scr24x_dev *dev = filp->private_data;
+	int ret;
+	int len;
+
+	if (count < CCID_HEADER_SIZE)
+		return -EINVAL;
+
+	if (mutex_lock_interruptible(&dev->lock))
+		return -ERESTARTSYS;
+
+	if (!dev->dev) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	ret = scr24x_wait_ready(dev);
+	if (ret < 0)
+		goto out;
+	len = CCID_HEADER_SIZE;
+	ret = read_chunk(dev, 0, len);
+	if (ret < 0)
+		goto out;
+
+	len += le32_to_cpu(*(__le32 *)(&dev->buf[CCID_LENGTH_OFFSET]));
+	if (len > sizeof(dev->buf)) {
+		ret = -EIO;
+		goto out;
+	}
+	read_chunk(dev, CCID_HEADER_SIZE, len);
+	if (ret < 0)
+		goto out;
+
+	if (len < count)
+		count = len;
+
+	if (copy_to_user(buf, dev->buf, count)) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	ret = count;
+out:
+	mutex_unlock(&dev->lock);
+	return ret;
+}
+
+static ssize_t scr24x_write(struct file *filp, const char __user *buf,
+					size_t count, loff_t *ppos)
+{
+	struct scr24x_dev *dev = filp->private_data;
+	size_t i, y;
+	int ret;
+
+	if (mutex_lock_interruptible(&dev->lock))
+		return -ERESTARTSYS;
+
+	if (!dev->dev) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	if (count > sizeof(dev->buf)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (copy_from_user(dev->buf, buf, count)) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	ret = scr24x_wait_ready(dev);
+	if (ret < 0)
+		goto out;
+
+	iowrite8(CMD_START, dev->regs + SCR24X_CMD_STATUS);
+	ret = scr24x_wait_ready(dev);
+	if (ret < 0)
+		goto out;
+
+	for (i = 0; i < count; i += 5) {
+		for (y = 0; y < 5 && i + y < count; y++)
+			iowrite8(dev->buf[i + y], dev->regs + SCR24X_DATA(y));
+
+		iowrite8(CMD_WRITE_BYTE, dev->regs + SCR24X_CMD_STATUS);
+		ret = scr24x_wait_ready(dev);
+		if (ret < 0)
+			goto out;
+	}
+
+	ret = count;
+out:
+	mutex_unlock(&dev->lock);
+	return ret;
+}
+
+static const struct file_operations scr24x_fops = {
+	.owner		= THIS_MODULE,
+	.read		= scr24x_read,
+	.write		= scr24x_write,
+	.open		= scr24x_open,
+	.release	= scr24x_release,
+	.llseek		= no_llseek,
+};
+
+static int scr24x_config_check(struct pcmcia_device *link, void *priv_data)
+{
+	if (resource_size(link->resource[PCMCIA_IOPORT_0]) != 0x11)
+		return -ENODEV;
+	return pcmcia_request_io(link);
+}
+
+static int scr24x_probe(struct pcmcia_device *link)
+{
+	struct scr24x_dev *dev;
+	int ret;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->devno = find_first_zero_bit(scr24x_minors, SCR24X_DEVS);
+	if (dev->devno >= SCR24X_DEVS) {
+		ret = -EBUSY;
+		goto err;
+	}
+
+	mutex_init(&dev->lock);
+	kref_init(&dev->refcnt);
+
+	link->priv = dev;
+	link->config_flags |= CONF_ENABLE_IRQ | CONF_AUTO_SET_IO;
+
+	ret = pcmcia_loop_config(link, scr24x_config_check, NULL);
+	if (ret < 0)
+		goto err;
+
+	dev->dev = &link->dev;
+	dev->regs = devm_ioport_map(&link->dev,
+				link->resource[PCMCIA_IOPORT_0]->start,
+				resource_size(link->resource[PCMCIA_IOPORT_0]));
+	if (!dev->regs) {
+		ret = -EIO;
+		goto err;
+	}
+
+	cdev_init(&dev->c_dev, &scr24x_fops);
+	dev->c_dev.owner = THIS_MODULE;
+	dev->c_dev.ops = &scr24x_fops;
+	ret = cdev_add(&dev->c_dev, MKDEV(MAJOR(scr24x_devt), dev->devno), 1);
+	if (ret < 0)
+		goto err;
+
+	ret = pcmcia_enable_device(link);
+	if (ret < 0) {
+		pcmcia_disable_device(link);
+		goto err;
+	}
+
+	device_create(scr24x_class, NULL, MKDEV(MAJOR(scr24x_devt), dev->devno),
+		      NULL, "scr24x%d", dev->devno);
+
+	dev_info(&link->dev, "SCR24x Chip Card Interface\n");
+	return 0;
+
+err:
+	if (dev->devno < SCR24X_DEVS)
+		clear_bit(dev->devno, scr24x_minors);
+	kfree (dev);
+	return ret;
+}
+
+static void scr24x_remove(struct pcmcia_device *link)
+{
+	struct scr24x_dev *dev = (struct scr24x_dev *)link->priv;
+
+	device_destroy(scr24x_class, MKDEV(MAJOR(scr24x_devt), dev->devno));
+	mutex_lock(&dev->lock);
+	pcmcia_disable_device(link);
+	cdev_del(&dev->c_dev);
+	clear_bit(dev->devno, scr24x_minors);
+	dev->dev = NULL;
+	mutex_unlock(&dev->lock);
+
+	kref_put(&dev->refcnt, scr24x_delete);
+}
+
+static const struct pcmcia_device_id scr24x_ids[] = {
+	PCMCIA_DEVICE_PROD_ID12("HP", "PC Card Smart Card Reader",
+					0x53cb94f9, 0xbfdf89a5),
+	PCMCIA_DEVICE_PROD_ID1("SCR241 PCMCIA", 0x6271efa3),
+	PCMCIA_DEVICE_PROD_ID1("SCR243 PCMCIA", 0x2054e8de),
+	PCMCIA_DEVICE_PROD_ID1("SCR24x PCMCIA", 0x54a33665),
+	PCMCIA_DEVICE_NULL
+};
+MODULE_DEVICE_TABLE(pcmcia, scr24x_ids);
+
+static struct pcmcia_driver scr24x_driver = {
+	.owner		= THIS_MODULE,
+	.name		= "scr24x_cs",
+	.probe		= scr24x_probe,
+	.remove		= scr24x_remove,
+	.id_table	= scr24x_ids,
+};
+
+static int __init scr24x_init(void)
+{
+	int ret;
+
+	scr24x_class = class_create(THIS_MODULE, "scr24x");
+	if (IS_ERR(scr24x_class))
+		return PTR_ERR(scr24x_class);
+
+	ret = alloc_chrdev_region(&scr24x_devt, 0, SCR24X_DEVS, "scr24x");
+	if (ret < 0)  {
+		class_destroy(scr24x_class);
+		return ret;
+	}
+
+	ret = pcmcia_register_driver(&scr24x_driver);
+	if (ret < 0) {
+		unregister_chrdev_region(scr24x_devt, SCR24X_DEVS);
+		class_destroy(scr24x_class);
+	}
+
+	return ret;
+}
+
+static void __exit scr24x_exit(void)
+{
+	pcmcia_unregister_driver(&scr24x_driver);
+	unregister_chrdev_region(scr24x_devt, SCR24X_DEVS);
+	class_destroy(scr24x_class);
+}
+
+module_init(scr24x_init);
+module_exit(scr24x_exit);
+
+MODULE_AUTHOR("Lubomir Rintel");
+MODULE_DESCRIPTION("SCR24x PCMCIA Smart Card Reader Driver");
+MODULE_LICENSE("GPL");