[PATCH 08/12] misc: Flexcard misc device support

[Holger Dengler <dengler@linutronix.de>]

The Flexcard PCI BAR0 contain registers for configuration but also
for informational purpose like error counter, statistical information
and some timestamps. The read-only mmap of the misc device offers the
userspace a fast access to these registers.

Signed-off-by: Benedikt Spranger <b.spranger@linutronix.de>
Signed-off-by: Holger Dengler <dengler@linutronix.de>
cc: Arnd Bergmann <arnd@arndb.de>
cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/mfd/Kconfig          |   1 +
 drivers/misc/Kconfig         |   6 ++
 drivers/misc/Makefile        |   1 +
 drivers/misc/flexcard_misc.c | 165 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 173 insertions(+)
 create mode 100644 drivers/misc/flexcard_misc.c

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 85fedf6..580f521 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -303,6 +303,7 @@ config MFD_FLEXCARD
 	tristate "Eberspaecher Flexcard PMC II Carrier Board"
 	select MFD_CORE
 	select IRQ_DOMAIN
+	select FLEXCARD_MISC
 	depends on PCI
 	help
 	  This is the core driver for the Eberspaecher Flexcard
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 64971ba..3f54b58 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -766,6 +766,12 @@ config PANEL_BOOT_MESSAGE
 	  An empty message will only clear the display at driver init time. Any other
 	  printf()-formatted message is valid with newline and escape codes.
 
+config FLEXCARD_MISC
+	tristate "Flexcard Misc Device driver"
+	depends on MFD_FLEXCARD
+	help
+	  Misc driver for Flexcard PMC II.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 3198336..08a1729 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_ECHO)		+= echo/
 obj-$(CONFIG_VEXPRESS_SYSCFG)	+= vexpress-syscfg.o
 obj-$(CONFIG_CXL_BASE)		+= cxl/
 obj-$(CONFIG_PANEL)             += panel.o
+obj-$(CONFIG_FLEXCARD_MISC)	+= flexcard_misc.o
 
 lkdtm-$(CONFIG_LKDTM)		+= lkdtm_core.o
 lkdtm-$(CONFIG_LKDTM)		+= lkdtm_bugs.o
diff --git a/drivers/misc/flexcard_misc.c b/drivers/misc/flexcard_misc.c
new file mode 100644
index 0000000..93c951c
--- /dev/null
+++ b/drivers/misc/flexcard_misc.c
@@ -0,0 +1,165 @@
+/*
+ * Eberspächer Flexcard PMC II Misc Device
+ *
+ * Copyright (c) 2014 - 2016, Linutronix GmbH
+ * Author: Benedikt Spranger <b.spranger@linutronix.de>
+ *         Holger Dengler <dengler@linutronix.de>
+ *
+ * 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/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kref.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+
+#include <linux/mfd/flexcard.h>
+
+#define FLEXCARD_MAX_NAME	16
+
+struct flexcard_misc {
+	char				name[FLEXCARD_MAX_NAME];
+	struct miscdevice		dev;
+	struct platform_device		*pdev;
+	struct fc_bar0_conf __iomem	*conf;
+	struct fc_bar0_nf __iomem	*nf;
+};
+
+static int flexcard_misc_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	unsigned long offset, vsize, psize, addr;
+	struct flexcard_misc *priv;
+	struct resource *res;
+
+	priv = container_of(filp->private_data, struct flexcard_misc, dev);
+	if (!priv)
+		return -EINVAL;
+
+	if (vma->vm_flags & (VM_WRITE | VM_EXEC))
+		return -EPERM;
+
+	res = platform_get_resource(priv->pdev, IORESOURCE_MEM, 0);
+	offset = vma->vm_pgoff << PAGE_SHIFT;
+	if (offset > resource_size(res)) {
+		dev_err(&priv->pdev->dev,
+			"mmap offset out of resource range\n");
+		return -EINVAL;
+	}
+
+	vsize = vma->vm_end - vma->vm_start;
+	psize = round_up(resource_size(res) - offset, PAGE_SIZE);
+	addr = (res->start + offset) >> PAGE_SHIFT;
+	if (vsize > psize) {
+		dev_err(&priv->pdev->dev,
+			"requested mmap mapping too large\n");
+		return -EINVAL;
+	}
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+	return io_remap_pfn_range(vma, vma->vm_start, addr, vsize,
+				  vma->vm_page_prot);
+}
+
+static const struct file_operations flexcard_misc_fops = {
+	.owner		= THIS_MODULE,
+	.open		= nonseekable_open,
+	.mmap		= flexcard_misc_mmap,
+	.llseek		= no_llseek,
+};
+
+static int flexcard_misc_iomap(struct platform_device *pdev)
+{
+	struct flexcard_misc *priv = platform_get_drvdata(pdev);
+	struct resource *res;
+	int ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENXIO;
+
+	priv->conf = ioremap_nocache(res->start, resource_size(res));
+	if (!priv->conf)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res) {
+		ret = -ENXIO;
+		goto out;
+	}
+
+	priv->nf = ioremap_nocache(res->start, resource_size(res));
+	if (!priv->nf) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	return 0;
+out:
+	iounmap(priv->conf);
+	return ret;
+}
+
+static int flexcard_misc_probe(struct platform_device *pdev)
+{
+	struct flexcard_misc *priv;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	ret = flexcard_misc_iomap(pdev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to map resource: %d\n", ret);
+		return ret;
+	}
+
+	snprintf(priv->name, sizeof(priv->name),
+		 "flexcard%d", pdev->id);
+	priv->dev.name = priv->name;
+	priv->dev.minor = MISC_DYNAMIC_MINOR;
+	priv->dev.fops = &flexcard_misc_fops;
+	priv->dev.parent = &pdev->dev;
+	priv->pdev = pdev;
+
+	ret = misc_register(&priv->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to register miscdevice: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int flexcard_misc_remove(struct platform_device *pdev)
+{
+	struct flexcard_misc *priv = platform_get_drvdata(pdev);
+
+	misc_deregister(&priv->dev);
+
+	return 0;
+}
+
+static struct platform_driver flexcard_misc_driver = {
+	.probe		= flexcard_misc_probe,
+	.remove		= flexcard_misc_remove,
+	.driver		= {
+		.name   = "flexcard-misc",
+	},
+};
+
+module_platform_driver(flexcard_misc_driver);
+
+MODULE_AUTHOR("Holger Dengler <dengler@linutronix.de>");
+MODULE_AUTHOR("Benedikt Spranger <b.spranger@linutronix.de>");
+MODULE_DESCRIPTION("Eberspaecher Flexcard PMC II Misc Driver");
+MODULE_LICENSE("GPL v2");
-- 
2.1.4