root/drivers/iommu/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;                                  \
                if (len < maxcol)                                       \
                        goto out;                                       \
                bytes = scnprintf(p, maxcol, str, __stringify(name),    \
                                 iommu_read_reg(obj, MMU_##name));      \
                p += bytes;                                             \
                len -= bytes;                                           \
        } 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 = kzalloc_objs(*cr, num);
        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);
}