omap-iommu-debug.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * omap iommu: debugfs interface
 *
 * Copyright (C) 2008-2009 Nokia Corporation
 *
 * Written by Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
 */

#include <linux/err.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/pm_runtime.h>
#include <linux/debugfs.h>
#include <linux/platform_data/iommu-omap.h>

#include "omap-iopgtable.h"
#include "omap-iommu.h"

static DEFINE_MUTEX(iommu_debug_lock);

static struct dentry *iommu_debug_root;

static inline bool is_omap_iommu_detached(struct omap_iommu *obj)
{
	return !obj->domain;
}

#define pr_reg(name)							\
	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 omap_iommu *obj, char *buf, ssize_t len)
{
	char *p = buf;

	pr_reg(REVISION);
	pr_reg(IRQSTATUS);
	pr_reg(IRQENABLE);
	pr_reg(WALKING_ST);
	pr_reg(CNTL);
	pr_reg(FAULT_AD);
	pr_reg(TTB);
	pr_reg(LOCK);
	pr_reg(LD_TLB);
	pr_reg(CAM);
	pr_reg(RAM);
	pr_reg(GFLUSH);
	pr_reg(FLUSH_ENTRY);
	pr_reg(READ_CAM);
	pr_reg(READ_RAM);
	pr_reg(EMU_FAULT_AD);
out:
	return p - buf;
}

static ssize_t omap_iommu_dump_ctx(struct omap_iommu *obj, char *buf,
				   ssize_t bytes)
{
	if (!obj || !buf)
		return -EINVAL;

	pm_runtime_get_sync(obj->dev);

	bytes = omap2_iommu_dump_ctx(obj, buf, bytes);

	pm_runtime_put_sync(obj->dev);

	return bytes;
}

static ssize_t debug_read_regs(struct file *file, char __user *userbuf,
			       size_t count, loff_t *ppos)
{
	struct omap_iommu *obj = file->private_data;
	char *p, *buf;
	ssize_t bytes;

	if (is_omap_iommu_detached(obj))
		return -EPERM;

	buf = kmalloc(count, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	p = buf;

	mutex_lock(&iommu_debug_lock);

	bytes = omap_iommu_dump_ctx(obj, p, count);
	if (bytes < 0)
		goto err;
	bytes = simple_read_from_buffer(userbuf, count, ppos, buf, bytes);

err:
	mutex_unlock(&iommu_debug_lock);
	kfree(buf);

	return bytes;
}

static int
__dump_tlb_entries(struct omap_iommu *obj, struct cr_regs *crs, int num)
{
	int i;
	struct iotlb_lock saved;
	struct cr_regs tmp;
	struct cr_regs *p = crs;

	pm_runtime_get_sync(obj->dev);
	iotlb_lock_get(obj, &saved);

	for_each_iotlb_cr(obj, num, i, tmp) {
		if (!iotlb_cr_valid(&tmp))
			continue;
		*p++ = tmp;
	}

	iotlb_lock_set(obj, &saved);
	pm_runtime_put_sync(obj->dev);

	return  p - crs;
}

static ssize_t iotlb_dump_cr(struct omap_iommu *obj, struct cr_regs *cr,
			     struct seq_file *s)
{
	seq_printf(s, "%08x %08x %01x\n", cr->cam, cr->ram,
		   (cr->cam & MMU_CAM_P) ? 1 : 0);
	return 0;
}

static size_t omap_dump_tlb_entries(struct omap_iommu *obj, struct seq_file *s)
{
	int i, num;
	struct cr_regs *cr;

	num = obj->nr_tlb_entries;

	cr = kcalloc(num, sizeof(*cr), GFP_KERNEL);
	if (!cr)
		return 0;

	num = __dump_tlb_entries(obj, cr, num);
	for (i = 0; i < num; i++)
		iotlb_dump_cr(obj, cr + i, s);
	kfree(cr);

	return 0;
}

static int tlb_show(struct seq_file *s, void *data)
{
	struct omap_iommu *obj = s->private;

	if (is_omap_iommu_detached(obj))
		return -EPERM;

	mutex_lock(&iommu_debug_lock);

	seq_printf(s, "%8s %8s\n", "cam:", "ram:");
	seq_puts(s, "-----------------------------------------\n");
	omap_dump_tlb_entries(obj, s);

	mutex_unlock(&iommu_debug_lock);

	return 0;
}

static void dump_ioptable(struct seq_file *s)
{
	int i, j;
	u32 da;
	u32 *iopgd, *iopte;
	struct omap_iommu *obj = s->private;

	spin_lock(&obj->page_table_lock);

	iopgd = iopgd_offset(obj, 0);
	for (i = 0; i < PTRS_PER_IOPGD; i++, iopgd++) {
		if (!*iopgd)
			continue;

		if (!(*iopgd & IOPGD_TABLE)) {
			da = i << IOPGD_SHIFT;
			seq_printf(s, "1: 0x%08x 0x%08x\n", da, *iopgd);
			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);
			seq_printf(s, "2: 0x%08x 0x%08x\n", da, *iopte);
		}
	}

	spin_unlock(&obj->page_table_lock);
}

static int pagetable_show(struct seq_file *s, void *data)
{
	struct omap_iommu *obj = s->private;

	if (is_omap_iommu_detached(obj))
		return -EPERM;

	mutex_lock(&iommu_debug_lock);

	seq_printf(s, "L: %8s %8s\n", "da:", "pte:");
	seq_puts(s, "--------------------------\n");
	dump_ioptable(s);

	mutex_unlock(&iommu_debug_lock);

	return 0;
}

#define DEBUG_FOPS_RO(name)						\
	static const struct file_operations name##_fops = {	        \
		.open = simple_open,					\
		.read = debug_read_##name,				\
		.llseek = generic_file_llseek,				\
	}

DEBUG_FOPS_RO(regs);
DEFINE_SHOW_ATTRIBUTE(tlb);
DEFINE_SHOW_ATTRIBUTE(pagetable);

void omap_iommu_debugfs_add(struct omap_iommu *obj)
{
	struct dentry *d;

	if (!iommu_debug_root)
		return;

	d = debugfs_create_dir(obj->name, iommu_debug_root);
	obj->debug_dir = d;

	debugfs_create_u32("nr_tlb_entries", 0400, d, &obj->nr_tlb_entries);
	debugfs_create_file("regs", 0400, d, obj, &regs_fops);
	debugfs_create_file("tlb", 0400, d, obj, &tlb_fops);
	debugfs_create_file("pagetable", 0400, d, obj, &pagetable_fops);
}

void omap_iommu_debugfs_remove(struct omap_iommu *obj)
{
	if (!obj->debug_dir)
		return;

	debugfs_remove_recursive(obj->debug_dir);
}

void __init omap_iommu_debugfs_init(void)
{
	iommu_debug_root = debugfs_create_dir("omap_iommu", NULL);
}

void __exit omap_iommu_debugfs_exit(void)
{
	debugfs_remove(iommu_debug_root);
}