path: root/drivers/firmware/tegra/bpmp-debugfs.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2017, NVIDIA CORPORATION.  All rights reserved.
 */
#include <linux/debugfs.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/uaccess.h>

#include <soc/tegra/bpmp.h>
#include <soc/tegra/bpmp-abi.h>

static DEFINE_MUTEX(bpmp_debug_lock);

struct seqbuf {
	char *buf;
	size_t pos;
	size_t size;
};

static void seqbuf_init(struct seqbuf *seqbuf, void *buf, size_t size)
{
	seqbuf->buf = buf;
	seqbuf->size = size;
	seqbuf->pos = 0;
}

static size_t seqbuf_avail(struct seqbuf *seqbuf)
{
	return seqbuf->pos < seqbuf->size ? seqbuf->size - seqbuf->pos : 0;
}

static size_t seqbuf_status(struct seqbuf *seqbuf)
{
	return seqbuf->pos <= seqbuf->size ? 0 : -EOVERFLOW;
}

static int seqbuf_eof(struct seqbuf *seqbuf)
{
	return seqbuf->pos >= seqbuf->size;
}

static int seqbuf_read(struct seqbuf *seqbuf, void *buf, size_t nbyte)
{
	nbyte = min(nbyte, seqbuf_avail(seqbuf));
	memcpy(buf, seqbuf->buf + seqbuf->pos, nbyte);
	seqbuf->pos += nbyte;
	return seqbuf_status(seqbuf);
}

static int seqbuf_read_u32(struct seqbuf *seqbuf, u32 *v)
{
	return seqbuf_read(seqbuf, v, 4);
}

static int seqbuf_read_str(struct seqbuf *seqbuf, const char **str)
{
	*str = seqbuf->buf + seqbuf->pos;
	seqbuf->pos += strnlen(*str, seqbuf_avail(seqbuf));
	seqbuf->pos++;
	return seqbuf_status(seqbuf);
}

static void seqbuf_seek(struct seqbuf *seqbuf, ssize_t offset)
{
	seqbuf->pos += offset;
}

/* map filename in Linux debugfs to corresponding entry in BPMP */
static const char *get_filename(struct tegra_bpmp *bpmp,
				const struct file *file, char *buf, int size)
{
	const char *root_path, *filename = NULL;
	char *root_path_buf;
	size_t root_len;
	size_t root_path_buf_len = 512;

	root_path_buf = kzalloc(root_path_buf_len, GFP_KERNEL);
	if (!root_path_buf)
		return NULL;

	root_path = dentry_path(bpmp->debugfs_mirror, root_path_buf,
				root_path_buf_len);
	if (IS_ERR(root_path))
		goto out;

	root_len = strlen(root_path);

	filename = dentry_path(file->f_path.dentry, buf, size);
	if (IS_ERR(filename)) {
		filename = NULL;
		goto out;
	}

	if (strlen(filename) < root_len || strncmp(filename, root_path, root_len)) {
		filename = NULL;
		goto out;
	}

	filename += root_len;

out:
	kfree(root_path_buf);
	return filename;
}

static int mrq_debug_open(struct tegra_bpmp *bpmp, const char *name,
			  u32 *fd, u32 *len, bool write)
{
	struct mrq_debug_request req = {
		.cmd = write ? CMD_DEBUG_OPEN_WO : CMD_DEBUG_OPEN_RO,
	};
	struct mrq_debug_response resp;
	struct tegra_bpmp_message msg = {
		.mrq = MRQ_DEBUG,
		.tx = {
			.data = &req,
			.size = sizeof(req),
		},
		.rx = {
			.data = &resp,
			.size = sizeof(resp),
		},
	};
	ssize_t sz_name;
	int err = 0;

	sz_name = strscpy(req.fop.name, name, sizeof(req.fop.name));
	if (sz_name < 0) {
		pr_err("File name too large: %s\n", name);
		return -EINVAL;
	}

	err = tegra_bpmp_transfer(bpmp, &msg);
	if (err < 0)
		return err;
	else if (msg.rx.ret < 0)
		return -EINVAL;

	*len = resp.fop.datalen;
	*fd = resp.fop.fd;

	return 0;
}

static int mrq_debug_close(struct tegra_bpmp *bpmp, u32 fd)
{
	struct mrq_debug_request req = {
		.cmd = CMD_DEBUG_CLOSE,
		.frd = {
			.fd = fd,
		},
	};
	struct mrq_debug_response resp;
	struct tegra_bpmp_message msg = {
		.mrq = MRQ_DEBUG,
		.tx = {
			.data = &req,
			.size = sizeof(req),
		},
		.rx = {
			.data = &resp,
			.size = sizeof(resp),
		},
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