User application interface(sysfs) (*partialy implemented)
"mmu-class" provides (5) to present some generic MMU information and
to control them too, like setting a TLB entry and a pagetable entry, from
userland through sysfs files. Since this is a normal MMU(TLB +
Pagetable + VMA) class, this can handle any MMU as well. This
"mmu-class" enables to implement an userland MMU manager for devices
later. This sysfs entires are just examples. "mmu-class" can be
considered as the entry point for any MMU to register itself to any
upper layter interface modules. "dspfs" registration also can be done
here.
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@xxxxxxxxx>
---
arch/arm/plat-omap/include/mach/mmu-class.h | 32 ++++
arch/arm/plat-omap/mmu-class.c | 213 +++++++++++++++++++++++++++
2 files changed, 245 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/plat-omap/include/mach/mmu-class.h
create mode 100644 arch/arm/plat-omap/mmu-class.c
diff --git a/arch/arm/plat-omap/include/mach/mmu-class.h b/arch/arm/plat-omap/include/mach/mmu-class.h
new file mode 100644
index 0000000..37e994b
--- /dev/null
+++ b/arch/arm/plat-omap/include/mach/mmu-class.h
@@ -0,0 +1,32 @@
+/* Generic MMU sysfs interface */
+#ifndef _MMU_CLASS_H_
+#define _MMU_CLASS_H_
+
+/* Primitive MMU info for any upper layer to handle */
+struct mmu_info {
+ char *name;
+#if 0 /* pagetable *//* REVISIT */
+ int (*pte_set)(struct mmu_info *i, void *entry, int way);
+ int (*pte_clear)(struct mmu_info *i, void *entry);
+ int (*dump_pagetable)(struct mmu_info *i, char *buf, void *entry);
+#endif
+ /* TLB *//* FIXME: multiple level TLB support */
+ int nr_ways;
+ int nr_sets;
+ int (*read_tlb)(struct mmu_info *i, void *entry, int way);
+ int (*write_tlb)(struct mmu_info *i, void *entry);
+ int (*dump_tlb)(struct mmu_info *i, char *buf, void *entry);
+#if 0 /* VMA *//* REVISIT */
+ unsigned long (*get_unmapped_area)(struct mmu_info *i,
+ unsigned long len);
+ dma_addr_t (*dvmap_region)(struct mmu_info *i, void *entry,
+ size_t bytes);
+ void (*dvunmap_region)(struct mmu_info *i unsigned long dvva,
+ size_t len);
+#endif
+};
+
+int mmu_register_sysfs(struct mmu_info *i);
+void mmu_unregister_sysfs(struct mmu_info *i);
+
+#endif /* _MMU_CLASS_H_ */
diff --git a/arch/arm/plat-omap/mmu-class.c b/arch/arm/plat-omap/mmu-class.c
new file mode 100644
index 0000000..03c80f6
--- /dev/null
+++ b/arch/arm/plat-omap/mmu-class.c
@@ -0,0 +1,213 @@
+/*
+ * Generic MMU sysfs interface
+ *
+ * Copyright (C) 2008 Nokia Corporation
+ * Written by Hiroshi DOYU <Hiroshi.DOYU@xxxxxxxxx>
+ *
+ * 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/module.h>
+#include <linux/kdev_t.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+
+#include <mach/mmu-class.h>
+
+static struct class *mmu_class;
+
+struct mmu_object {
+ struct device *dev;
+ struct mmu_info *info;
+};
+#define to_mmu_info(dev) \
+ (((struct mmu_object *)dev_get_drvdata(dev))->info)
+
+static ssize_t generic_attr_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct mmu_info *info = to_mmu_info(dev);
+ int err;
+ if (strcmp(attr->attr.name, "name") == 0)
+ err = sprintf(buf, "%s\n", info->name);
+ else if (strcmp(attr->attr.name, "set") == 0)
+ err = sprintf(buf, "%d\n", info->nr_sets);
+ else if (strcmp(attr->attr.name, "way") == 0)
+ err = sprintf(buf, "%d\n", info->nr_ways);
+ else
+ err = -EINVAL;
+ return err;
+}
+
+static ssize_t tlb_entries_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ unsigned long long *entry, *p;
+ int i, nr_entries, bytes = 0;
+ struct mmu_info *info = to_mmu_info(dev);
+
+ if (!info->read_tlb || !info->dump_tlb)
+ return -EIO;
+
+ nr_entries = info->nr_ways * info->nr_sets;
+ entry = kzalloc(nr_entries * sizeof(*entry), GFP_KERNEL);
+ if (!entry)
+ return -ENOMEM;
+ p = entry;
+ for (i = 0; i < info->nr_ways; i++) {
+ int err;
+ p += i * info->nr_sets;
+ err = info->read_tlb(info, (unsigned long *)p, i);
+ if (err)
+ goto out;
+ }
+ bytes = info->dump_tlb(info, buf, (void *)entry);
+out:
+ kfree(entry);
+ return bytes;
+}
+
+static ssize_t tlb_entries_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct mmu_info *info = to_mmu_info(dev);
+ if (count != sizeof(long long))
+ return -EINVAL;
+ if (!info->write_tlb)
+ return -EIO;
+ return info->write_tlb(info, (unsigned long *)buf);
+}
+
+/*
+ * MMU
+ */
+static DEVICE_ATTR(name, S_IRUGO, generic_attr_show, NULL);
+static struct attribute *mmu_attrs[] = {
+ &dev_attr_name.attr,
+ NULL,
+};
+static struct attribute_group mmu_attr_grp = {
+ .attrs = mmu_attrs,
+};
+
+/*
+ * TLB
+ */
+static DEVICE_ATTR(way, S_IRUGO, generic_attr_show, NULL);
+static DEVICE_ATTR(set, S_IRUGO, generic_attr_show, NULL);
+static DEVICE_ATTR(buf, S_IRUGO, tlb_entries_show, tlb_entries_store);
+static struct attribute *tlb_attrs[] = {
+ &dev_attr_way.attr,
+ &dev_attr_set.attr,
+ &dev_attr_buf.attr,
+ NULL,
+};
+
+static struct attribute_group tlb_attr_grp = {
+ .name = "tlb",
+ .attrs = tlb_attrs,
+};
+
+/*
+ * PageTable: REVISIT
+ */
+static DEVICE_ATTR(pgt, S_IRUGO, NULL, NULL);
+static struct attribute *pgt_attrs[] = {
+ &dev_attr_pgt.attr,
+ NULL,
+};
+static struct attribute_group pgt_attr_grp = {
+ .attrs = pgt_attrs,
+};
+
+int mmu_register_sysfs(struct mmu_info *info)
+{
+ int err;
+ struct mmu_object *mmu;
+
+ if (!info || !info->name)
+ return -EINVAL;
+ mmu = kzalloc(sizeof(*mmu), GFP_KERNEL);
+ if (!mmu)
+ return -ENOMEM;
+ mmu->info = info;
+ mmu->dev = device_create(mmu_class, NULL, 0, "%s", info->name);
+ if (IS_ERR(mmu->dev)) {
+ err = PTR_ERR(mmu->dev);
+ goto err_device;
+ }
+ dev_set_drvdata(mmu->dev, mmu);
+ err = sysfs_create_group(&mmu->dev->kobj, &mmu_attr_grp);
+ if (err)
+ goto err_mmu_attr;
+ err = sysfs_create_group(&mmu->dev->kobj, &tlb_attr_grp);
+ if (err)
+ goto err_tlb_attr;
+ err = sysfs_create_group(&mmu->dev->kobj, &pgt_attr_grp);
+ if (err)
+ goto err_pgt_attr;
+
+ /*
+ * You can add any upper layer interface(ex: dspfs, debugfs)
+ * Or these can be configurable here ultimately.
+ */
+ return 0;
+err_mmu_attr:
+ sysfs_remove_group(&mmu->dev->kobj, &pgt_attr_grp);
+err_pgt_attr:
+ sysfs_remove_group(&mmu->dev->kobj, &tlb_attr_grp);
+err_tlb_attr:
+ device_unregister(mmu->dev);
+err_device:
+ kfree(mmu);
+ return err;
+}
+EXPORT_SYMBOL(mmu_register_sysfs);
+
+static int match_by_info(struct device *dev, void *data)
+{
+ return data == (void *)to_mmu_info(dev);
+}
+
+void mmu_unregister_sysfs(struct mmu_info *info)
+{
+ struct mmu_object *mmu;
+ struct device *dev;
+
+ if (!info)
+ return;
+ dev = class_find_device(mmu_class, NULL, info, match_by_info);
+ if (!dev)
+ return;
+ mmu = dev_get_drvdata(dev);
+
+ sysfs_remove_group(&mmu->dev->kobj, &tlb_attr_grp);
+ sysfs_remove_group(&mmu->dev->kobj, &pgt_attr_grp);
+ sysfs_remove_group(&mmu->dev->kobj, &mmu_attr_grp);
+
+ dev_set_drvdata(mmu->dev, NULL);
+ device_unregister(mmu->dev);
+ kfree(mmu);
+}
+EXPORT_SYMBOL(mmu_unregister_sysfs);
+
+static int __init mmu_class_init(void)
+{
+ mmu_class = class_create(THIS_MODULE, "mmu");
+ if (IS_ERR(mmu_class))
+ return PTR_ERR(mmu_class);
+ return 0;
+}
+static void __exit mmu_class_exit(void)
+{
+ class_destroy(mmu_class);
+}
+arch_initcall(mmu_class_init);
+module_exit(mmu_class_exit);
+
+MODULE_DESCRIPTION("Generic MMU handling interface");
+MODULE_AUTHOR("Hiroshi DOYU <Hiroshi.DOYU@xxxxxxxxx>");
+MODULE_LICENSE("GPL");
--
1.5.5.1.357.g1af8b
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