[PATCH v2] char/pcmcia: add scr24x_cs chip card interface driver

[Lubomir Rintel]

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@xxxxx>
---
Changes since v1:
 * Turn scr24x_devt into a global variable
 * Include slab.h
 * Check the kzalloc() return value in probe()
 * Comment on locking in release()

 MAINTAINERS                     |   5 +
 drivers/char/pcmcia/Kconfig     |  11 ++
 drivers/char/pcmcia/Makefile    |   1 +
 drivers/char/pcmcia/scr24x_cs.c | 370 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 387 insertions(+)
 create mode 100644 drivers/char/pcmcia/scr24x_cs.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 5327bbe..8dc6a9f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10608,6 +10608,11 @@ W:	http://www.sunplus.com
 S:	Supported
 F:	arch/score/
 
+SCR24X CHIP CARD INTERFACE DRIVER
+M:	Lubomir Rintel <lkundrak@xxxxx>
+S:	Supported
+F:	drivers/char/pcmcia/scr24x_cs.c
+
 SYSTEM CONTROL & POWER INTERFACE (SCPI) Message Protocol drivers
 M:	Sudeep Holla <sudeep.holla@xxxxxxx>
 L:	linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
diff --git a/drivers/char/pcmcia/Kconfig b/drivers/char/pcmcia/Kconfig
index 8d3dfb0..1d1e7da 100644
--- a/drivers/char/pcmcia/Kconfig
+++ b/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
diff --git a/drivers/char/pcmcia/Makefile b/drivers/char/pcmcia/Makefile
index 0aae209..5b836bc 100644
--- a/drivers/char/pcmcia/Makefile
+++ b/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
diff --git a/drivers/char/pcmcia/scr24x_cs.c b/drivers/char/pcmcia/scr24x_cs.c
new file mode 100644
index 0000000..165e2de
--- /dev/null
+++ b/drivers/char/pcmcia/scr24x_cs.c
@@ -0,0 +1,370 @@
+/*
+ * 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 <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");
-- 
2.7.4