Subject: [RFC][PATCH 2/2] Example to show use of uio pgprot

From: Kumar Gala <[email-masked]>
Date: Fri, 28 Oct 2011 10:50:30 -0500

---
 drivers/uio/uio_dpa.c |  200 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 200 insertions(+), 0 deletions(-)
 create mode 100644 drivers/uio/uio_dpa.c

diff --git a/drivers/uio/uio_dpa.c b/drivers/uio/uio_dpa.c
new file mode 100644
index 0000000..19360f2
--- /dev/null
+++ b/drivers/uio/uio_dpa.c
@@ -0,0 +1,200 @@
+/* Copyright 2011 Freescale Semiconductor, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of Freescale Semiconductor nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") as published by the Free Software
+ * Foundation, either version 2 of that License or (at your option) any
+ * later version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Freescale Semiconductor ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL Freescale Semiconductor BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "bman_private.h"
+#include "qman_private.h"
+
+static const char dpa_uio_version[] = "USDPAA UIO portal driver v0.2";
+
+static LIST_HEAD(uio_portal_list);
+
+struct dpa_uio_info {
+	atomic_t ref; /* exclusive, only one open() at a time */
+	struct uio_info uio;
+	void *addr_ci;
+	char name[16]; /* big enough for "qman-uio-xx" */
+	struct platform_device *pdev;
+	struct list_head node;
+};
+
+static int dpa_uio_open(struct uio_info *info, struct inode *inode)
+{
+	struct dpa_uio_info *i = container_of(info, struct dpa_uio_info, uio);
+	if (!atomic_dec_and_test(&i->ref)) {
+		atomic_inc(&i->ref);
+		return -EBUSY;
+	}
+	return 0;
+}
+
+static int dpa_uio_release(struct uio_info *info, struct inode *inode)
+{
+	struct dpa_uio_info *i = container_of(info, struct dpa_uio_info, uio);
+	atomic_inc(&i->ref);
+	return 0;
+}
+
+static pgprot_t dpa_uio_pgprot(struct uio_info *info, unsigned int mem_idx,
+				   pgprot_t prot)
+{
+	if (mem_idx == DPA_PORTAL_CE)
+		/* It's the cache-enabled portal region. NB, we shouldn't use
+		 * pgprot_cached() here because it includes _PAGE_COHERENT. The
+		 * region is cachable but *not* coherent - stashing (if enabled)
+		 * leads to "coherent-like" behaviour, otherwise the driver
+		 * explicitly invalidates/prefetches. */
+		return pgprot_cached_noncoherent(prot);
+	/* Otherwise it's the cache-inhibited portal region */
+	return pgprot_noncached(prot);
+}
+
+static irqreturn_t dpa_uio_irq_handler(int irq, struct uio_info *info)
+{
+	struct dpa_uio_info *i = container_of(info, struct dpa_uio_info, uio);
+	/* This is the only code outside the regular portal driver that
+	 * manipulates any portal register, so rather than breaking that
+	 * encapsulation I am simply hard-coding the offset to the inhibit
+	 * register here. */
+	out_be32(i->addr_ci + 0xe0c, ~(u32)0);
+	return IRQ_HANDLED;
+}
+
+static void __init dpa_uio_portal_init(struct dpa_uio_portal *p,
+				const struct dpa_uio_class *c)
+{
+	struct dpa_uio_info *info;
+	const struct resource *res;
+	u32 index;
+	int irq, ret;
+
+	/* allocate 'info' */
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return;
+	atomic_set(&info->ref, 1);
+	if (p->type == dpa_uio_portal_bman) {
+		res = &p->bm_cfg->addr_phys[0];
+		index = p->bm_cfg->public_cfg.index;
+		irq = p->bm_cfg->public_cfg.irq;
+	} else {
+		res = &p->qm_cfg->addr_phys[0];
+		index = p->qm_cfg->public_cfg.index;
+		irq = p->qm_cfg->public_cfg.irq;
+	}
+	/* We need to map the cache-inhibited region in the kernel for
+	 * interrupt-handling purposes. */
+	info->addr_ci = ioremap_prot(res[DPA_PORTAL_CI].start,
+				resource_size(&res[DPA_PORTAL_CI]),
+				_PAGE_GUARDED | _PAGE_NO_CACHE);
+	/* Name the UIO device according to the cell-index. It's supposed to be
+	 * unique for each device class (Qman/Bman), and is also a convenient
+	 * way for user-space to find the UIO device that corresponds to a given
+	 * portal device-tree node. */
+	sprintf(info->name, "%s%x", c->dev_prefix, index);
+	info->pdev = platform_device_alloc(info->name, -1);
+	if (!info->pdev) {
+		iounmap(info->addr_ci);
+		kfree(info);
+		pr_err("dpa_uio_portal: platform_device_alloc() failed\n");
+		return;
+	}
+	ret = platform_device_add(info->pdev);
+	if (ret) {
+		platform_device_put(info->pdev);
+		iounmap(info->addr_ci);
+		kfree(info);
+		pr_err("dpa_uio_portal: platform_device_add() failed\n");
+		return;
+	}
+	info->uio.name = info->name;
+	info->uio.version = dpa_uio_version;
+	info->uio.mem[DPA_PORTAL_CE].name = "cena";
+	info->uio.mem[DPA_PORTAL_CE].addr = res[DPA_PORTAL_CE].start;
+	info->uio.mem[DPA_PORTAL_CE].size = resource_size(&res[DPA_PORTAL_CE]);
+	info->uio.mem[DPA_PORTAL_CE].memtype = UIO_MEM_PHYS;
+	info->uio.mem[DPA_PORTAL_CI].name = "cinh";
+	info->uio.mem[DPA_PORTAL_CI].addr = res[DPA_PORTAL_CI].start;
+	info->uio.mem[DPA_PORTAL_CI].size = resource_size(&res[DPA_PORTAL_CI]);
+	info->uio.mem[DPA_PORTAL_CI].memtype = UIO_MEM_PHYS;
+	info->uio.irq = irq;
+	info->uio.handler = dpa_uio_irq_handler;
+	info->uio.set_pgprot = dpa_uio_pgprot;
+	info->uio.open = dpa_uio_open;
+	info->uio.release = dpa_uio_release;
+	ret = uio_register_device(&info->pdev->dev, &info->uio);
+	if (ret) {
+		platform_device_del(info->pdev);
+		platform_device_put(info->pdev);
+		iounmap(info->addr_ci);
+		kfree(info);
+		pr_err("dpa_uio_portal: UIO registration failed\n");
+		return;
+	}
+	list_add_tail(&info->node, &uio_portal_list);
+	pr_info("USDPAA portal initialised, %s\n", info->name);
+}
+
+static int __init dpa_uio_init(void)
+{
+	const struct dpa_uio_class *classes[3], **c = classes;
+	classes[0] = dpa_uio_bman();
+	classes[1] = dpa_uio_qman();
+	classes[2] = NULL;
+	while (*c) {
+		struct dpa_uio_portal *p;
+		list_for_each_entry(p, &(*c)->list, node)
+			dpa_uio_portal_init(p, *c);
+		c++;
+	}
+	pr_info("USDPAA portal layer loaded\n");
+	return 0;
+}
+
+static void __exit dpa_uio_exit(void)
+{
+	struct dpa_uio_info *info, *tmp;
+	list_for_each_entry_safe(info, tmp, &uio_portal_list, node) {
+		list_del(&info->node);
+		uio_unregister_device(&info->uio);
+		platform_device_del(info->pdev);
+		platform_device_put(info->pdev);
+		iounmap(info->addr_ci);
+		pr_info("USDPAA portal removed, %s\n", info->name);
+		kfree(info);
+	}
+	pr_info("USDPAA portal layer unloaded\n");
+}
+
+
+module_init(dpa_uio_init)
+module_exit(dpa_uio_exit)
+MODULE_LICENSE("GPL");
+
-- 
1.7.3.4