From: John Feeney <jfeeney@redhat.com>
Date: Tue, 21 Apr 2009 19:02:08 -0400
Subject: [misc] I/O AT: add drivers/dca
Message-id: 49EE5070.2050604@redhat.com
O-Subject: [RHEL5.4 PATCH 4/8] Update I/O AT: add drivers/dca
Bugzilla: 436048
RH-Acked-by: Prarit Bhargava <prarit@redhat.com>
RH-Acked-by: John W. Linville <linville@redhat.com>

bz436048 Update I/O AT code to upstream

This patch adds the dca directory and files - specifically for bz252949
  Kconfig     |   11 ++
  Makefile    |    2
  dca-core.c  |  275
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  dca-sysfs.c |   88 +++++++++++++++++++
 4 files changed, 376 insertions(+)

The commits to each file and any modifications are listed below.
drivers/dca/Kconfig
 same as commit except added dependency on DMAENGINE_V3 and
  PCI for kabi
    7589670f37736bcc119ebfbd69aafea6d585d1d4 Nelson 10/16/07

drivers/dca/dca-sysfs.c
 same as upstream
   7589670f37736bcc119ebfbd69aafea6d585d1d4 Nelson 10/16/07
   765cdb6cef63c0b41c3f6c9285769080b3f41bb0 Sievers 2/8/08
   7f1b358a236ee9c19657a619ac6f2dcabcaa0924 Sosnowski 7/23/08

drivers/dca/Makefile
 same as upstream
   7589670f37736bcc119ebfbd69aafea6d585d1d4 Nelson 10/16/07

drivers/dca/dca-core.c
 same as commits:
   7589670f37736bcc119ebfbd69aafea6d585d1d4 Nelson 10/16/07
   7f1b358a236ee9c19657a619ac6f2dcabcaa0924 Sosnowski 7/23/08

diff --git a/drivers/dca/Kconfig b/drivers/dca/Kconfig
new file mode 100644
index 0000000..0d91b4b
--- /dev/null
+++ b/drivers/dca/Kconfig
@@ -0,0 +1,11 @@
+#
+# DCA server configuration
+#
+
+config DCA
+	tristate
+	depends on DMA_ENGINE_V3 && PCI
+	default m
+	---help---
+	  This is a server to help modules that want to use Direct Cache
+	  Access to find DCA providers that will supply correct CPU tags.
diff --git a/drivers/dca/Makefile b/drivers/dca/Makefile
new file mode 100644
index 0000000..b2db56b
--- /dev/null
+++ b/drivers/dca/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_DCA) += dca.o
+dca-objs := dca-core.o dca-sysfs.o
diff --git a/drivers/dca/dca-core.c b/drivers/dca/dca-core.c
new file mode 100644
index 0000000..ec249d2
--- /dev/null
+++ b/drivers/dca/dca-core.c
@@ -0,0 +1,275 @@
+/*
+ * Copyright(c) 2007 Intel Corporation. All rights reserved.
+ *
+ * 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 of the License, 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; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The full GNU General Public License is included in this distribution in the
+ * file called COPYING.
+ */
+
+/*
+ * This driver supports an interface for DCA clients and providers to meet.
+ */
+
+#include <linux/kernel.h>
+#include <linux/notifier.h>
+#include <linux/device.h>
+#include <linux/dca.h>
+
+#define DCA_VERSION "1.4"
+
+MODULE_VERSION(DCA_VERSION);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Intel Corporation");
+
+static DEFINE_SPINLOCK(dca_lock);
+
+static LIST_HEAD(dca_providers);
+
+static struct dca_provider *dca_find_provider_by_dev(struct device *dev)
+{
+	struct dca_provider *dca, *ret = NULL;
+
+	list_for_each_entry(dca, &dca_providers, node) {
+		if ((!dev) || (dca->ops->dev_managed(dca, dev))) {
+			ret = dca;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+/**
+ * dca_add_requester - add a dca client to the list
+ * @dev - the device that wants dca service
+ */
+int dca_add_requester(struct device *dev)
+{
+	struct dca_provider *dca;
+	int err, slot = -ENODEV;
+
+	if (!dev)
+		return -EFAULT;
+
+	spin_lock(&dca_lock);
+
+	/* check if the requester has not been added already */
+	dca = dca_find_provider_by_dev(dev);
+	if (dca) {
+		spin_unlock(&dca_lock);
+		return -EEXIST;
+	}
+
+	list_for_each_entry(dca, &dca_providers, node) {
+		slot = dca->ops->add_requester(dca, dev);
+		if (slot >= 0)
+			break;
+	}
+	if (slot < 0) {
+		spin_unlock(&dca_lock);
+		return slot;
+	}
+
+	err = dca_sysfs_add_req(dca, dev, slot);
+	if (err) {
+		dca->ops->remove_requester(dca, dev);
+		spin_unlock(&dca_lock);
+		return err;
+	}
+
+	spin_unlock(&dca_lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dca_add_requester);
+
+/**
+ * dca_remove_requester - remove a dca client from the list
+ * @dev - the device that wants dca service
+ */
+int dca_remove_requester(struct device *dev)
+{
+	struct dca_provider *dca;
+	int slot;
+
+	if (!dev)
+		return -EFAULT;
+
+	spin_lock(&dca_lock);
+	dca = dca_find_provider_by_dev(dev);
+	if (!dca) {
+		spin_unlock(&dca_lock);
+		return -ENODEV;
+	}
+	slot = dca->ops->remove_requester(dca, dev);
+	if (slot < 0) {
+		spin_unlock(&dca_lock);
+		return slot;
+	}
+
+	dca_sysfs_remove_req(dca, slot);
+
+	spin_unlock(&dca_lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dca_remove_requester);
+
+/**
+ * dca_common_get_tag - return the dca tag (serves both new and old api)
+ * @dev - the device that wants dca service
+ * @cpu - the cpuid as returned by get_cpu()
+ */
+u8 dca_common_get_tag(struct device *dev, int cpu)
+{
+	struct dca_provider *dca;
+	u8 tag;
+
+	spin_lock(&dca_lock);
+
+	dca = dca_find_provider_by_dev(dev);
+	if (!dca) {
+		spin_unlock(&dca_lock);
+		return -ENODEV;
+	}
+	tag = dca->ops->get_tag(dca, dev, cpu);
+
+	spin_unlock(&dca_lock);
+	return tag;
+}
+
+/**
+ * dca3_get_tag - return the dca tag to the requester device
+ *                for the given cpu (new api)
+ * @dev - the device that wants dca service
+ * @cpu - the cpuid as returned by get_cpu()
+ */
+u8 dca3_get_tag(struct device *dev, int cpu)
+{
+	if (!dev)
+		return -EFAULT;
+
+	return dca_common_get_tag(dev, cpu);
+}
+EXPORT_SYMBOL_GPL(dca3_get_tag);
+
+/**
+ * dca_get_tag - return the dca tag for the given cpu (old api)
+ * @cpu - the cpuid as returned by get_cpu()
+ */
+u8 dca_get_tag(int cpu)
+{
+	struct device *dev = NULL;
+
+	return dca_common_get_tag(dev, cpu);
+}
+EXPORT_SYMBOL_GPL(dca_get_tag);
+
+/**
+ * alloc_dca_provider - get data struct for describing a dca provider
+ * @ops - pointer to struct of dca operation function pointers
+ * @priv_size - size of extra mem to be added for provider's needs
+ */
+struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size)
+{
+	struct dca_provider *dca;
+	int alloc_size;
+
+	alloc_size = (sizeof(*dca) + priv_size);
+	dca = kzalloc(alloc_size, GFP_KERNEL);
+	if (!dca)
+		return NULL;
+	dca->ops = ops;
+
+	return dca;
+}
+EXPORT_SYMBOL_GPL(alloc_dca_provider);
+
+/**
+ * free_dca_provider - release the dca provider data struct
+ * @ops - pointer to struct of dca operation function pointers
+ * @priv_size - size of extra mem to be added for provider's needs
+ */
+void free_dca_provider(struct dca_provider *dca)
+{
+	kfree(dca);
+}
+EXPORT_SYMBOL_GPL(free_dca_provider);
+
+static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
+
+/**
+ * register_dca_provider - register a dca provider
+ * @dca - struct created by alloc_dca_provider()
+ * @dev - device providing dca services
+ */
+int register_dca_provider(struct dca_provider *dca, struct device *dev)
+{
+	int err;
+
+	err = dca_sysfs_add_provider(dca, dev);
+	if (err)
+		return err;
+	list_add(&dca->node, &dca_providers);
+	blocking_notifier_call_chain(&dca_provider_chain,
+				     DCA_PROVIDER_ADD, NULL);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(register_dca_provider);
+
+/**
+ * unregister_dca_provider - remove a dca provider
+ * @dca - struct created by alloc_dca_provider()
+ */
+void unregister_dca_provider(struct dca_provider *dca)
+{
+	blocking_notifier_call_chain(&dca_provider_chain,
+				     DCA_PROVIDER_REMOVE, NULL);
+	list_del(&dca->node);
+	dca_sysfs_remove_provider(dca);
+}
+EXPORT_SYMBOL_GPL(unregister_dca_provider);
+
+/**
+ * dca_register_notify - register a client's notifier callback
+ */
+void dca_register_notify(struct notifier_block *nb)
+{
+	blocking_notifier_chain_register(&dca_provider_chain, nb);
+}
+EXPORT_SYMBOL_GPL(dca_register_notify);
+
+/**
+ * dca_unregister_notify - remove a client's notifier callback
+ */
+void dca_unregister_notify(struct notifier_block *nb)
+{
+	blocking_notifier_chain_unregister(&dca_provider_chain, nb);
+}
+EXPORT_SYMBOL_GPL(dca_unregister_notify);
+
+static int __init dca_init(void)
+{
+	printk(KERN_ERR "dca service started, version %s\n", DCA_VERSION);
+	return dca_sysfs_init();
+}
+
+static void __exit dca_exit(void)
+{
+	dca_sysfs_exit();
+}
+
+module_init(dca_init);
+module_exit(dca_exit);
+
diff --git a/drivers/dca/dca-sysfs.c b/drivers/dca/dca-sysfs.c
new file mode 100644
index 0000000..3d47e9d
--- /dev/null
+++ b/drivers/dca/dca-sysfs.c
@@ -0,0 +1,88 @@
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/idr.h>
+#include <linux/kdev_t.h>
+#include <linux/err.h>
+#include <linux/dca.h>
+
+static struct class *dca_class;
+static struct idr dca_idr;
+static spinlock_t dca_idr_lock;
+
+int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
+{
+	struct device *cd;
+	static int req_count;
+
+	cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1),
+			   "requester%d", req_count++);
+	if (IS_ERR(cd))
+		return PTR_ERR(cd);
+	return 0;
+}
+
+void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
+{
+	device_destroy(dca_class, MKDEV(0, slot + 1));
+}
+
+int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
+{
+	struct device *cd;
+	int err = 0;
+
+idr_try_again:
+	if (!idr_pre_get(&dca_idr, GFP_KERNEL))
+		return -ENOMEM;
+	spin_lock(&dca_idr_lock);
+	err = idr_get_new(&dca_idr, dca, &dca->id);
+	spin_unlock(&dca_idr_lock);
+	switch (err) {
+	case 0:
+		break;
+	case -EAGAIN:
+		goto idr_try_again;
+	default:
+		return err;
+	}
+
+	cd = device_create(dca_class, dev, MKDEV(0, 0), "dca%d", dca->id);
+	if (IS_ERR(cd)) {
+		spin_lock(&dca_idr_lock);
+		idr_remove(&dca_idr, dca->id);
+		spin_unlock(&dca_idr_lock);
+		return PTR_ERR(cd);
+	}
+	dca->cd = cd;
+	return 0;
+}
+
+void dca_sysfs_remove_provider(struct dca_provider *dca)
+{
+	device_unregister(dca->cd);
+	dca->cd = NULL;
+	spin_lock(&dca_idr_lock);
+	idr_remove(&dca_idr, dca->id);
+	spin_unlock(&dca_idr_lock);
+}
+
+int __init dca_sysfs_init(void)
+{
+	idr_init(&dca_idr);
+	spin_lock_init(&dca_idr_lock);
+
+	dca_class = class_create(THIS_MODULE, "dca");
+	if (IS_ERR(dca_class)) {
+		idr_destroy(&dca_idr);
+		return PTR_ERR(dca_class);
+	}
+	return 0;
+}
+
+void __exit dca_sysfs_exit(void)
+{
+	class_destroy(dca_class);
+	idr_destroy(&dca_idr);
+}
+