misc: mic: SCIF Hardware Bus

The SCIF hardware bus abstracts the low level hardware driver details
like interrupts and mapping remote memory so that the same SCIF driver
can work without any changes with the MIC host or card driver as long
as the hardware bus operations are implemented. The SCIF hardware
device is registered by the host and card drivers on the SCIF hardware
bus resulting in probing the SCIF driver.

Reviewed-by: Nikhil Rao <nikhil.rao@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 210 insertions, 0 deletions

diff --git a/drivers/misc/mic/bus/scif_bus.c b/drivers/misc/mic/bus/scif_bus.c
new file mode 100644
index 000000000000..2da7ceed015d
--- /dev/null
+++ b/drivers/misc/mic/bus/scif_bus.c
@@ -0,0 +1,210 @@
+/*
+ * Intel MIC Platform Software Stack (MPSS)
+ *
+ * Copyright(c) 2014 Intel Corporation.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * Intel Symmetric Communications Interface Bus driver.
+ */
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/idr.h>
+#include <linux/dma-mapping.h>
+
+#include "scif_bus.h"
+
+static ssize_t device_show(struct device *d,
+			   struct device_attribute *attr, char *buf)
+{
+	struct scif_hw_dev *dev = dev_to_scif(d);
+
+	return sprintf(buf, "0x%04x\n", dev->id.device);
+}
+
+static DEVICE_ATTR_RO(device);
+
+static ssize_t vendor_show(struct device *d,
+			   struct device_attribute *attr, char *buf)
+{
+	struct scif_hw_dev *dev = dev_to_scif(d);
+
+	return sprintf(buf, "0x%04x\n", dev->id.vendor);
+}
+
+static DEVICE_ATTR_RO(vendor);
+
+static ssize_t modalias_show(struct device *d,
+			     struct device_attribute *attr, char *buf)
+{
+	struct scif_hw_dev *dev = dev_to_scif(d);
+
+	return sprintf(buf, "scif:d%08Xv%08X\n",
+		       dev->id.device, dev->id.vendor);
+}
+
+static DEVICE_ATTR_RO(modalias);
+
+static struct attribute *scif_dev_attrs[] = {
+	&dev_attr_device.attr,
+	&dev_attr_vendor.attr,
+	&dev_attr_modalias.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(scif_dev);
+
+static inline int scif_id_match(const struct scif_hw_dev *dev,
+				const struct scif_hw_dev_id *id)
+{
+	if (id->device != dev->id.device && id->device != SCIF_DEV_ANY_ID)
+		return 0;
+
+	return id->vendor == SCIF_DEV_ANY_ID || id->vendor == dev->id.vendor;
+}
+
+/*
+ * This looks through all the IDs a driver claims to support.  If any of them
+ * match, we return 1 and the kernel will call scif_dev_probe().
+ */
+static int scif_dev_match(struct device *dv, struct device_driver *dr)
+{
+	unsigned int i;
+	struct scif_hw_dev *dev = dev_to_scif(dv);
+	const struct scif_hw_dev_id *ids;
+
+	ids = drv_to_scif(dr)->id_table;
+	for (i = 0; ids[i].device; i++)
+		if (scif_id_match(dev, &ids[i]))
+			return 1;
+	return 0;
+}
+
+static int scif_uevent(struct device *dv, struct kobj_uevent_env *env)
+{
+	struct scif_hw_dev *dev = dev_to_scif(dv);
+
+	return add_uevent_var(env, "MODALIAS=scif:d%08Xv%08X",
+			      dev->id.device, dev->id.vendor);
+}
+
+static int scif_dev_probe(struct device *d)
+{
+	struct scif_hw_dev *dev = dev_to_scif(d);
+	struct scif_driver *drv = drv_to_scif(dev->dev.driver);
+
+	return drv->probe(dev);
+}
+
+static int scif_dev_remove(struct device *d)
+{
+	struct scif_hw_dev *dev = dev_to_scif(d);
+	struct scif_driver *drv = drv_to_scif(dev->dev.driver);
+
+	drv->remove(dev);
+	return 0;
+}
+
+static struct bus_type scif_bus = {
+	.name  = "scif_bus",
+	.match = scif_dev_match,
+	.dev_groups = scif_dev_groups,
+	.uevent = scif_uevent,
+	.probe = scif_dev_probe,
+	.remove = scif_dev_remove,
+};
+
+int scif_register_driver(struct scif_driver *driver)
+{
+	driver->driver.bus = &scif_bus;
+	return driver_register(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(scif_register_driver);
+
+void scif_unregister_driver(struct scif_driver *driver)
+{
+	driver_unregister(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(scif_unregister_driver);
+
+static void scif_release_dev(struct device *d)
+{
+	struct scif_hw_dev *sdev = dev_to_scif(d);
+
+	kfree(sdev);
+}
+
+struct scif_hw_dev *
+scif_register_device(struct device *pdev, int id, struct dma_map_ops *dma_ops,
+		     struct scif_hw_ops *hw_ops, u8 dnode, u8 snode,
+		     struct mic_mw *mmio, struct mic_mw *aper, void *dp,
+		     void __iomem *rdp, struct dma_chan **chan, int num_chan)
+{
+	int ret;
+	struct scif_hw_dev *sdev;
+
+	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
+	if (!sdev)
+		return ERR_PTR(-ENOMEM);
+
+	sdev->dev.parent = pdev;
+	sdev->id.device = id;
+	sdev->id.vendor = SCIF_DEV_ANY_ID;
+	sdev->dev.archdata.dma_ops = dma_ops;
+	sdev->dev.release = scif_release_dev;
+	sdev->hw_ops = hw_ops;
+	sdev->dnode = dnode;
+	sdev->snode = snode;
+	dev_set_drvdata(&sdev->dev, sdev);
+	sdev->dev.bus = &scif_bus;
+	sdev->mmio = mmio;
+	sdev->aper = aper;
+	sdev->dp = dp;
+	sdev->rdp = rdp;
+	sdev->dev.dma_mask = &sdev->dev.coherent_dma_mask;
+	dma_set_mask(&sdev->dev, DMA_BIT_MASK(64));
+	sdev->dma_ch = chan;
+	sdev->num_dma_ch = num_chan;
+	dev_set_name(&sdev->dev, "scif-dev%u", sdev->dnode);
+	/*
+	 * device_register() causes the bus infrastructure to look for a
+	 * matching driver.
+	 */
+	ret = device_register(&sdev->dev);
+	if (ret)
+		goto free_sdev;
+	return sdev;
+free_sdev:
+	kfree(sdev);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(scif_register_device);
+
+void scif_unregister_device(struct scif_hw_dev *sdev)
+{
+	device_unregister(&sdev->dev);
+}
+EXPORT_SYMBOL_GPL(scif_unregister_device);
+
+static int __init scif_init(void)
+{
+	return bus_register(&scif_bus);
+}
+
+static void __exit scif_exit(void)
+{
+	bus_unregister(&scif_bus);
+}
+
+core_initcall(scif_init);
+module_exit(scif_exit);
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("Intel(R) SCIF Bus driver");
+MODULE_LICENSE("GPL v2");