OMAP: iommu: add initial debugfs support

This enables to peek the following data.

$ /debug/iommu/isp# ls
mem             nr_tlb_entries  regs
mmap            pagetable       tlb
$ /debug/iommu/isp# head pagetable
L:      da:      pa:
-----------------------------------------
2: 00001000 8ae4a002
2: 00002000 8e7bb002
2: 00003000 8ae49002
2: 00004000 8ae65002
.....
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/iommu2.c

@@ -217,10 +217,19 @@ static ssize_t omap2_dump_cr(struct iommu *obj, struct cr_regs *cr, char *buf)
 }
 
 #define pr_reg(name)							\
-	p += sprintf(p, "%20s: %08x\n",					\
-		     __stringify(name), iommu_read_reg(obj, MMU_##name));
-
-static ssize_t omap2_iommu_dump_ctx(struct iommu *obj, char *buf)
+	do {								\
+		ssize_t bytes;						\
+		const char *str = "%20s: %08x\n";			\
+		const int maxcol = 32;					\
+		bytes = snprintf(p, maxcol, str, __stringify(name),	\
+				 iommu_read_reg(obj, MMU_##name));	\
+		p += bytes;						\
+		len -= bytes;						\
+		if (len < maxcol)					\
+			goto out;					\
+	} while (0)
+
+static ssize_t omap2_iommu_dump_ctx(struct iommu *obj, char *buf, ssize_t len)
 {
 	char *p = buf;
 
@@ -242,7 +251,7 @@ static ssize_t omap2_iommu_dump_ctx(struct iommu *obj, char *buf)
 	pr_reg(READ_CAM);
 	pr_reg(READ_RAM);
 	pr_reg(EMU_FAULT_AD);
-
+out:
 	return p - buf;
 }
 

arch/arm/plat-omap/Kconfig

@@ -120,6 +120,10 @@ config OMAP_MBOX_FWK
 config OMAP_IOMMU
 	tristate
 
+config OMAP_IOMMU_DEBUG
+	depends on OMAP_IOMMU
+	tristate
+
 choice
         prompt "System timer"
 	default OMAP_MPU_TIMER

arch/arm/plat-omap/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_ARCH_OMAP16XX) += ocpi.o
 
 obj-$(CONFIG_OMAP_MCBSP) += mcbsp.o
 obj-$(CONFIG_OMAP_IOMMU) += iommu.o iovmm.o
+obj-$(CONFIG_OMAP_IOMMU_DEBUG) += iommu-debug.o
 
 obj-$(CONFIG_CPU_FREQ) += cpu-omap.o
 obj-$(CONFIG_OMAP_DM_TIMER) += dmtimer.o

arch/arm/plat-omap/include/mach/iommu.h

@@ -95,7 +95,7 @@ struct iommu_functions {
 
 	void (*save_ctx)(struct iommu *obj);
 	void (*restore_ctx)(struct iommu *obj);
-	ssize_t (*dump_ctx)(struct iommu *obj, char *buf);
+	ssize_t (*dump_ctx)(struct iommu *obj, char *buf, ssize_t len);
 };
 
 struct iommu_platform_data {
@@ -162,7 +162,7 @@ extern void uninstall_iommu_arch(const struct iommu_functions *ops);
 extern int foreach_iommu_device(void *data,
 				int (*fn)(struct device *, void *));
 
-extern ssize_t iommu_dump_ctx(struct iommu *obj, char *buf);
-extern size_t dump_tlb_entries(struct iommu *obj, char *buf);
+extern ssize_t iommu_dump_ctx(struct iommu *obj, char *buf, ssize_t len);
+extern size_t dump_tlb_entries(struct iommu *obj, char *buf, ssize_t len);
 
 #endif /* __MACH_IOMMU_H */

arch/arm/plat-omap/iommu-debug.c

+/*
+ * omap iommu: debugfs interface
+ *
+ * Copyright (C) 2008-2009 Nokia Corporation
+ *
+ * Written by Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
+ *
+ * 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/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <linux/platform_device.h>
+#include <linux/debugfs.h>
+
+#include <mach/iommu.h>
+#include <mach/iovmm.h>
+
+#include "iopgtable.h"
+
+#define MAXCOLUMN 100 /* for short messages */
+
+static DEFINE_MUTEX(iommu_debug_lock);
+
+static struct dentry *iommu_debug_root;
+
+static ssize_t debug_read_ver(struct file *file, char __user *userbuf,
+			      size_t count, loff_t *ppos)
+{
+	u32 ver = iommu_arch_version();
+	char buf[MAXCOLUMN], *p = buf;
+
+	p += sprintf(p, "H/W version: %d.%d\n", (ver >> 4) & 0xf , ver & 0xf);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);
+}
+
+static ssize_t debug_read_regs(struct file *file, char __user *userbuf,
+			       size_t count, loff_t *ppos)
+{
+	struct iommu *obj = file->private_data;
+	char *p, *buf;
+	ssize_t bytes;
+
+	buf = kmalloc(count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	p = buf;
+
+	mutex_lock(&iommu_debug_lock);
+
+	bytes = iommu_dump_ctx(obj, p, count);
+	bytes = simple_read_from_buffer(userbuf, count, ppos, buf, bytes);
+
+	mutex_unlock(&iommu_debug_lock);
+	kfree(buf);
+
+	return bytes;
+}
+
+static ssize_t debug_read_tlb(struct file *file, char __user *userbuf,
+			      size_t count, loff_t *ppos)
+{
+	struct iommu *obj = file->private_data;
+	char *p, *buf;
+	ssize_t bytes, rest;
+
+	buf = kmalloc(count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	p = buf;
+
+	mutex_lock(&iommu_debug_lock);
+
+	p += sprintf(p, "%8s %8s\n", "cam:", "ram:");
+	p += sprintf(p, "-----------------------------------------\n");
+	rest = count - (p - buf);
+	p += dump_tlb_entries(obj, p, rest);
+
+	bytes = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);
+
+	mutex_unlock(&iommu_debug_lock);
+	kfree(buf);
+
+	return bytes;
+}
+
+static ssize_t debug_write_pagetable(struct file *file,
+		     const char __user *userbuf, size_t count, loff_t *ppos)
+{
+	struct iotlb_entry e;
+	struct cr_regs cr;
+	int err;
+	struct iommu *obj = file->private_data;
+	char buf[MAXCOLUMN], *p = buf;
+
+	count = min(count, sizeof(buf));
+
+	mutex_lock(&iommu_debug_lock);
+	if (copy_from_user(p, userbuf, count)) {
+		mutex_unlock(&iommu_debug_lock);
+		return -EFAULT;
+	}
+
+	sscanf(p, "%x %x", &cr.cam, &cr.ram);
+	if (!cr.cam || !cr.ram) {
+		mutex_unlock(&iommu_debug_lock);
+		return -EINVAL;
+	}
+
+	iotlb_cr_to_e(&cr, &e);
+	err = iopgtable_store_entry(obj, &e);
+	if (err)
+		dev_err(obj->dev, "%s: fail to store cr\n", __func__);
+
+	mutex_unlock(&iommu_debug_lock);
+	return count;
+}
+
+#define dump_ioptable_entry_one(lv, da, val)			\
+	({							\
+		int __err = 0;					\
+		ssize_t bytes;					\
+		const int maxcol = 22;				\
+		const char *str = "%d: %08x %08x\n";		\
+		bytes = snprintf(p, maxcol, str, lv, da, val);	\
+		p += bytes;					\
+		len -= bytes;					\
+		if (len < maxcol)				\
+			__err = -ENOMEM;			\
+		__err;						\
+	})
+
+static ssize_t dump_ioptable(struct iommu *obj, char *buf, ssize_t len)
+{
+	int i;
+	u32 *iopgd;
+	char *p = buf;
+
+	spin_lock(&obj->page_table_lock);
+
+	iopgd = iopgd_offset(obj, 0);
+	for (i = 0; i < PTRS_PER_IOPGD; i++, iopgd++) {
+		int j, err;
+		u32 *iopte;
+		u32 da;
+
+		if (!*iopgd)
+			continue;
+
+		if (!(*iopgd & IOPGD_TABLE)) {
+			da = i << IOPGD_SHIFT;
+
+			err = dump_ioptable_entry_one(1, da, *iopgd);
+			if (err)
+				goto out;
+			continue;
+		}
+
+		iopte = iopte_offset(iopgd, 0);
+
+		for (j = 0; j < PTRS_PER_IOPTE; j++, iopte++) {
+			if (!*iopte)
+				continue;
+
+			da = (i << IOPGD_SHIFT) + (j << IOPTE_SHIFT);
+			err = dump_ioptable_entry_one(2, da, *iopgd);
+			if (err)
+				goto out;
+		}
+	}
+out:
+	spin_unlock(&obj->page_table_lock);
+
+	return p - buf;
+}
+
+static ssize_t debug_read_pagetable(struct file *file, char __user *userbuf,
+				    size_t count, loff_t *ppos)
+{
+	struct iommu *obj = file->private_data;
+	char *p, *buf;
+	size_t bytes;
+
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	p = buf;
+
+	p += sprintf(p, "L: %8s %8s\n", "da:", "pa:");
+	p += sprintf(p, "-----------------------------------------\n");
+
+	mutex_lock(&iommu_debug_lock);
+
+	bytes = PAGE_SIZE - (p - buf);
+	p += dump_ioptable(obj, p, bytes);
+
+	bytes = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);
+
+	mutex_unlock(&iommu_debug_lock);
+	free_page((unsigned long)buf);
+
+	return bytes;
+}
+
+static ssize_t debug_read_mmap(struct file *file, char __user *userbuf,
+			       size_t count, loff_t *ppos)
+{
+	struct iommu *obj = file->private_data;
+	char *p, *buf;
+	struct iovm_struct *tmp;
+	int uninitialized_var(i);
+	ssize_t bytes;
+
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	p = buf;
+
+	p += sprintf(p, "%-3s %-8s %-8s %6s %8s\n",
+		     "No", "start", "end", "size", "flags");
+	p += sprintf(p, "-------------------------------------------------\n");
+
+	mutex_lock(&iommu_debug_lock);
+
+	list_for_each_entry(tmp, &obj->mmap, list) {
+		size_t len;
+		const char *str = "%3d %08x-%08x %6x %8x\n";
+		const int maxcol = 39;
+
+		len = tmp->da_end - tmp->da_start;
+		p += snprintf(p, maxcol, str,
+			      i, tmp->da_start, tmp->da_end, len, tmp->flags);
+
+		if (PAGE_SIZE - (p - buf) < maxcol)
+			break;
+		i++;
+	}
+
+	bytes = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);
+
+	mutex_unlock(&iommu_debug_lock);
+	free_page((unsigned long)buf);
+
+	return bytes;
+}
+
+static ssize_t debug_read_mem(struct file *file, char __user *userbuf,
+			      size_t count, loff_t *ppos)
+{
+	struct iommu *obj = file->private_data;
+	char *p, *buf;
+	struct iovm_struct *area;
+	ssize_t bytes;
+
+	count = min_t(ssize_t, count, PAGE_SIZE);
+
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	p = buf;
+
+	mutex_lock(&iommu_debug_lock);
+
+	area = find_iovm_area(obj, (u32)ppos);
+	if (IS_ERR(area)) {
+		bytes = -EINVAL;
+		goto err_out;
+	}
+	memcpy(p, area->va, count);
+	p += count;
+
+	bytes = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);
+err_out:
+	mutex_unlock(&iommu_debug_lock);
+	free_page((unsigned long)buf);
+
+	return bytes;
+}
+
+static ssize_t debug_write_mem(struct file *file, const char __user *userbuf,
+			       size_t count, loff_t *ppos)
+{
+	struct iommu *obj = file->private_data;
+	struct iovm_struct *area;
+	char *p, *buf;
+
+	count = min_t(size_t, count, PAGE_SIZE);
+
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	p = buf;
+
+	mutex_lock(&iommu_debug_lock);
+
+	if (copy_from_user(p, userbuf, count)) {
+		count =  -EFAULT;
+		goto err_out;
+	}
+
+	area = find_iovm_area(obj, (u32)ppos);
+	if (IS_ERR(area)) {
+		count = -EINVAL;
+		goto err_out;
+	}
+	memcpy(area->va, p, count);
+err_out:
+	mutex_unlock(&iommu_debug_lock);
+	free_page((unsigned long)buf);
+
+	return count;
+}
+
+static int debug_open_generic(struct inode *inode, struct file *file)
+{
+	file->private_data = inode->i_private;
+	return 0;
+}
+
+#define DEBUG_FOPS(name)						\
+	static const struct file_operations debug_##name##_fops = {	\
+		.open = debug_open_generic,				\
+		.read = debug_read_##name,				\
+		.write = debug_write_##name,				\
+	};
+
+#define DEBUG_FOPS_RO(name)						\
+	static const struct file_operations debug_##name##_fops = {	\
+		.open = debug_open_generic,				\
+		.read = debug_read_##name,				\
+	};
+
+DEBUG_FOPS_RO(ver);
+DEBUG_FOPS_RO(regs);
+DEBUG_FOPS_RO(tlb);
+DEBUG_FOPS(pagetable);
+DEBUG_FOPS_RO(mmap);
+DEBUG_FOPS(mem);
+
+#define __DEBUG_ADD_FILE(attr, mode)					\
+	{								\
+		struct dentry *dent;					\
+		dent = debugfs_create_file(#attr, mode, parent,		\
+					   obj, &debug_##attr##_fops);	\
+		if (!dent)						\
+			return -ENOMEM;					\
+	}
+
+#define DEBUG_ADD_FILE(name) __DEBUG_ADD_FILE(name, 600)
+#define DEBUG_ADD_FILE_RO(name) __DEBUG_ADD_FILE(name, 400)
+
+static int iommu_debug_register(struct device *dev, void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct iommu *obj = platform_get_drvdata(pdev);
+	struct dentry *d, *parent;
+
+	if (!obj || !obj->dev)
+		return -EINVAL;
+
+	d = debugfs_create_dir(obj->name, iommu_debug_root);
+	if (!d)
+		return -ENOMEM;
+	parent = d;
+
+	d = debugfs_create_u8("nr_tlb_entries", 400, parent,
+			      (u8 *)&obj->nr_tlb_entries);
+	if (!d)
+		return -ENOMEM;
+
+	DEBUG_ADD_FILE_RO(ver);
+	DEBUG_ADD_FILE_RO(regs);
+	DEBUG_ADD_FILE_RO(tlb);
+	DEBUG_ADD_FILE(pagetable);
+	DEBUG_ADD_FILE_RO(mmap);
+	DEBUG_ADD_FILE(mem);
+
+	return 0;
+}
+
+static int __init iommu_debug_init(void)
+{
+	struct dentry *d;
+	int err;
+
+	d = debugfs_create_dir("iommu", NULL);
+	if (!d)
+		return -ENOMEM;
+	iommu_debug_root = d;
+
+	err = foreach_iommu_device(d, iommu_debug_register);
+	if (err)
+		goto err_out;
+	return 0;
+
+err_out:
+	debugfs_remove_recursive(iommu_debug_root);
+	return err;
+}
+module_init(iommu_debug_init)
+
+static void __exit iommu_debugfs_exit(void)
+{
+	debugfs_remove_recursive(iommu_debug_root);
+}
+module_exit(iommu_debugfs_exit)
+
+MODULE_DESCRIPTION("omap iommu: debugfs interface");
+MODULE_AUTHOR("Hiroshi DOYU <Hiroshi.DOYU@nokia.com>");
+MODULE_LICENSE("GPL v2");

arch/arm/plat-omap/iommu.c

@@ -351,16 +351,14 @@ EXPORT_SYMBOL_GPL(flush_iotlb_all);
 
 #if defined(CONFIG_OMAP_IOMMU_DEBUG_MODULE)
 
-ssize_t iommu_dump_ctx(struct iommu *obj, char *buf)
+ssize_t iommu_dump_ctx(struct iommu *obj, char *buf, ssize_t bytes)
 {
-	ssize_t bytes;
-
 	if (!obj || !buf)
 		return -EINVAL;
 
 	clk_enable(obj->clk);
 
-	bytes = arch_iommu->dump_ctx(obj, buf);
+	bytes = arch_iommu->dump_ctx(obj, buf, bytes);
 
 	clk_disable(obj->clk);
 
@@ -368,7 +366,7 @@ ssize_t iommu_dump_ctx(struct iommu *obj, char *buf)
 }
 EXPORT_SYMBOL_GPL(iommu_dump_ctx);
 
-static int __dump_tlb_entries(struct iommu *obj, struct cr_regs *crs)
+static int __dump_tlb_entries(struct iommu *obj, struct cr_regs *crs, int num)
 {
 	int i;
 	struct iotlb_lock saved, l;
@@ -379,7 +377,7 @@ static int __dump_tlb_entries(struct iommu *obj, struct cr_regs *crs)
 	iotlb_lock_get(obj, &saved);
 	memcpy(&l, &saved, sizeof(saved));
 
-	for (i = 0; i < obj->nr_tlb_entries; i++) {
+	for (i = 0; i < num; i++) {
 		struct cr_regs tmp;
 
 		iotlb_lock_get(obj, &l);
@@ -402,18 +400,21 @@ static int __dump_tlb_entries(struct iommu *obj, struct cr_regs *crs)
  * @obj:	target iommu
  * @buf:	output buffer
  **/
-size_t dump_tlb_entries(struct iommu *obj, char *buf)
+size_t dump_tlb_entries(struct iommu *obj, char *buf, ssize_t bytes)
 {
-	int i, n;
+	int i, num;
 	struct cr_regs *cr;
 	char *p = buf;
 
-	cr = kcalloc(obj->nr_tlb_entries, sizeof(*cr), GFP_KERNEL);
+	num = bytes / sizeof(*cr);
+	num = min(obj->nr_tlb_entries, num);
+
+	cr = kcalloc(num, sizeof(*cr), GFP_KERNEL);
 	if (!cr)
 		return 0;
 
-	n = __dump_tlb_entries(obj, cr);
-	for (i = 0; i < n; i++)
+	num = __dump_tlb_entries(obj, cr, num);
+	for (i = 0; i < num; i++)
 		p += iotlb_dump_cr(obj, cr + i, p);
 	kfree(cr);