path: root/drivers/thunderbolt/switch.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Thunderbolt Cactus Ridge driver - switch/port utility functions
 *
 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
 */

#include <linux/delay.h>
#include <linux/idr.h>
#include <linux/nvmem-provider.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include "tb.h"

/* Switch authorization from userspace is serialized by this lock */
static DEFINE_MUTEX(switch_lock);

/* Switch NVM support */

#define NVM_DEVID		0x05
#define NVM_VERSION		0x08
#define NVM_CSS			0x10
#define NVM_FLASH_SIZE		0x45

#define NVM_MIN_SIZE		SZ_32K
#define NVM_MAX_SIZE		SZ_512K

static DEFINE_IDA(nvm_ida);

struct nvm_auth_status {
	struct list_head list;
	uuid_t uuid;
	u32 status;
};

/*
 * Hold NVM authentication failure status per switch This information
 * needs to stay around even when the switch gets power cycled so we
 * keep it separately.
 */
static LIST_HEAD(nvm_auth_status_cache);
static DEFINE_MUTEX(nvm_auth_status_lock);

static struct nvm_auth_status *__nvm_get_auth_status(const struct tb_switch *sw)
{
	struct nvm_auth_status *st;

	list_for_each_entry(st, &nvm_auth_status_cache, list) {
		if (uuid_equal(&st->uuid, sw->uuid))
			return st;
	}

	return NULL;
}

static void nvm_get_auth_status(const struct tb_switch *sw, u32 *status)
{
	struct nvm_auth_status *st;

	mutex_lock(&nvm_auth_status_lock);
	st = __nvm_get_auth_status(sw);
	mutex_unlock(&nvm_auth_status_lock);

	*status = st ? st->status : 0;
}

static void nvm_set_auth_status(const struct tb_switch *sw, u32 status)
{
	struct nvm_auth_status *st;

	if (WARN_ON(!sw->uuid))
		return;

	mutex_lock(&nvm_auth_status_lock);
	st = __nvm_get_auth_status(sw);

	if (!st) {
		st = kzalloc(sizeof(*st), GFP_KERNEL);
		if (!st)
			goto unlock;

		memcpy(&st->uuid, sw->uuid, sizeof(st->uuid));
		INIT_LIST_HEAD(&st->list);
		list_add_tail(&st->list, &nvm_auth_status_cache);
	}

	st->status = status;
unlock:
	mutex_unlock(&nvm_auth_status_lock);
}

static void nvm_clear_auth_status(const struct tb_switch *sw)
{
	struct nvm_auth_status *st;

	mutex_lock(&nvm_auth_status_lock);
	st = __nvm_get_auth_status(sw);
	if (st) {
		list_del(&st->list);
		kfree(st);
	}
	mutex_unlock(&nvm_auth_status_lock);
}

static int nvm_validate_and_write(struct tb_switch *sw)
{
	unsigned int image_size, hdr_size;
	const u8 *buf = sw->nvm->buf;
	u16 ds_size;
	int ret;

	if (!buf)
		return -EINVAL;

	image_size = sw->nvm->buf_data_size;
	if (image_size < NVM_MIN_SIZE || image_size > NVM_MAX_SIZE)
		return -EINVAL;

	/*
	 * FARB pointer must point inside the image and must at least
	 * contain parts of the digital section we will be reading here.
	 */
	hdr_size = (*(u32 *)buf) & 0xffffff;
	if (hdr_size + NVM_DEVID + 2 >= image_size)
		return -EINVAL;

	/* Digital section start should be aligned to 4k page */
	if (!IS_ALIGNED(hdr_size, SZ_4K))
		return -EINVAL;

	/*
	 * Read digital section size and check that it also fits inside
	 * the image.
	 */
	ds_size = *(u16 *)(buf + hdr_size);
	if (ds_size >= image_size)
		return -EINVAL;

	if (!sw->safe_mode) {
		u16 device_id;

		/*
		 * Make sure the device ID in the image matches the one
		 * we read from the switch config space.
		 */
		device_id = *(u16 *)(buf + hdr_size + NVM_DEVID);
		if (device_id != sw->config.device_id)
			return -EINVAL;

		if (sw->generation < 3) {
			/* Write CSS headers first */
			ret = dma_port_flash_write(sw->dma_port,
				DMA_PORT_CSS_ADDRESS, buf + NVM_CSS,
				DMA_PORT_CSS_MAX_SIZE);
			if (ret)
				return ret;
		}

		/* Skip headers in the image */
		buf += hdr_size;
		image_size -= hdr_size;
	}

	return dma_port_flash_write(sw->dma_port, 0, buf, image_size);
}

static int nvm_authenticate_host(struct tb_switch *sw)
{
	int ret;

	/*
	 * Root switch NVM upgrade requires that we disconnect the
	 * existing paths first (in case it is not in safe mode
	 * already).
	 */
	if (!sw->safe_mode) {
		ret = tb_domain_disconnect_all_paths(sw->tb);
		if (ret)
			return ret;
		/*
		 * The host controller goes away pretty soon after this if
		 * everything goes well so getting timeout is expected.
		 */
		ret = dma_port_flash_update_auth(sw->dma_port);
		return ret == -ETIMEDOUT ? 0 : ret;
	}

	/*
	 * From safe mode we can get out by just power cycling the
	 * switch.
	 */
	dma_port_power_cycle(sw->dma_port);
	return 0;
}

static int nvm_authenticate_device(struct tb_switch *sw)
{
	int ret, retries = 10;

	ret = dma_port_flash_update_auth(sw->dma_port);
	if (ret && ret != -ETIMEDOUT)