linux/drivers/thunderbolt/retimer.c
Mika Westerberg 8720037181 thunderbolt: Enable/disable sideband depending on USB4 port offline mode
When USB4 port is in offline mode (this mean there is no device
attached) we want to keep the sideband up to make it possible to
communicate with the retimers. In the same way there is no need to
enable sideband transactions when the USB4 port is not offline as they
are already up.

For this reason make the enabling/disabling depend on the USB4 port
offline status.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2023-06-12 08:38:01 +03:00

566 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Thunderbolt/USB4 retimer support.
*
* Copyright (C) 2020, Intel Corporation
* Authors: Kranthi Kuntala <kranthi.kuntala@intel.com>
* Mika Westerberg <mika.westerberg@linux.intel.com>
*/
#include <linux/delay.h>
#include <linux/pm_runtime.h>
#include <linux/sched/signal.h>
#include "sb_regs.h"
#include "tb.h"
#define TB_MAX_RETIMER_INDEX 6
/**
* tb_retimer_nvm_read() - Read contents of retimer NVM
* @rt: Retimer device
* @address: NVM address (in bytes) to start reading
* @buf: Data read from NVM is stored here
* @size: Number of bytes to read
*
* Reads retimer NVM and copies the contents to @buf. Returns %0 if the
* read was successful and negative errno in case of failure.
*/
int tb_retimer_nvm_read(struct tb_retimer *rt, unsigned int address, void *buf,
size_t size)
{
return usb4_port_retimer_nvm_read(rt->port, rt->index, address, buf, size);
}
static int nvm_read(void *priv, unsigned int offset, void *val, size_t bytes)
{
struct tb_nvm *nvm = priv;
struct tb_retimer *rt = tb_to_retimer(nvm->dev);
int ret;
pm_runtime_get_sync(&rt->dev);
if (!mutex_trylock(&rt->tb->lock)) {
ret = restart_syscall();
goto out;
}
ret = tb_retimer_nvm_read(rt, offset, val, bytes);
mutex_unlock(&rt->tb->lock);
out:
pm_runtime_mark_last_busy(&rt->dev);
pm_runtime_put_autosuspend(&rt->dev);
return ret;
}
static int nvm_write(void *priv, unsigned int offset, void *val, size_t bytes)
{
struct tb_nvm *nvm = priv;
struct tb_retimer *rt = tb_to_retimer(nvm->dev);
int ret = 0;
if (!mutex_trylock(&rt->tb->lock))
return restart_syscall();
ret = tb_nvm_write_buf(nvm, offset, val, bytes);
mutex_unlock(&rt->tb->lock);
return ret;
}
static int tb_retimer_nvm_add(struct tb_retimer *rt)
{
struct tb_nvm *nvm;
int ret;
nvm = tb_nvm_alloc(&rt->dev);
if (IS_ERR(nvm)) {
ret = PTR_ERR(nvm) == -EOPNOTSUPP ? 0 : PTR_ERR(nvm);
goto err_nvm;
}
ret = tb_nvm_read_version(nvm);
if (ret)
goto err_nvm;
ret = tb_nvm_add_active(nvm, nvm_read);
if (ret)
goto err_nvm;
ret = tb_nvm_add_non_active(nvm, nvm_write);
if (ret)
goto err_nvm;
rt->nvm = nvm;
return 0;
err_nvm:
dev_dbg(&rt->dev, "NVM upgrade disabled\n");
if (!IS_ERR(nvm))
tb_nvm_free(nvm);
return ret;
}
static int tb_retimer_nvm_validate_and_write(struct tb_retimer *rt)
{
unsigned int image_size;
const u8 *buf;
int ret;
ret = tb_nvm_validate(rt->nvm);
if (ret)
return ret;
buf = rt->nvm->buf_data_start;
image_size = rt->nvm->buf_data_size;
ret = usb4_port_retimer_nvm_write(rt->port, rt->index, 0, buf,
image_size);
if (ret)
return ret;
rt->nvm->flushed = true;
return 0;
}
static int tb_retimer_nvm_authenticate(struct tb_retimer *rt, bool auth_only)
{
u32 status;
int ret;
if (auth_only) {
ret = usb4_port_retimer_nvm_set_offset(rt->port, rt->index, 0);
if (ret)
return ret;
}
ret = usb4_port_retimer_nvm_authenticate(rt->port, rt->index);
if (ret)
return ret;
usleep_range(100, 150);
/*
* Check the status now if we still can access the retimer. It
* is expected that the below fails.
*/
ret = usb4_port_retimer_nvm_authenticate_status(rt->port, rt->index,
&status);
if (!ret) {
rt->auth_status = status;
return status ? -EINVAL : 0;
}
return 0;
}
static ssize_t device_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct tb_retimer *rt = tb_to_retimer(dev);
return sysfs_emit(buf, "%#x\n", rt->device);
}
static DEVICE_ATTR_RO(device);
static ssize_t nvm_authenticate_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct tb_retimer *rt = tb_to_retimer(dev);
int ret;
if (!mutex_trylock(&rt->tb->lock))
return restart_syscall();
if (!rt->nvm)
ret = -EAGAIN;
else if (rt->no_nvm_upgrade)
ret = -EOPNOTSUPP;
else
ret = sysfs_emit(buf, "%#x\n", rt->auth_status);
mutex_unlock(&rt->tb->lock);
return ret;
}
static void tb_retimer_nvm_authenticate_status(struct tb_port *port, u32 *status)
{
int i;
tb_port_dbg(port, "reading NVM authentication status of retimers\n");
/*
* Before doing anything else, read the authentication status.
* If the retimer has it set, store it for the new retimer
* device instance.
*/
for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++)
usb4_port_retimer_nvm_authenticate_status(port, i, &status[i]);
}
static void tb_retimer_set_inbound_sbtx(struct tb_port *port)
{
int i;
/*
* When USB4 port is online sideband communications are
* already up.
*/
if (!usb4_port_device_is_offline(port->usb4))
return;
tb_port_dbg(port, "enabling sideband transactions\n");
for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++)
usb4_port_retimer_set_inbound_sbtx(port, i);
}
static void tb_retimer_unset_inbound_sbtx(struct tb_port *port)
{
int i;
/*
* When USB4 port is offline we need to keep the sideband
* communications up to make it possible to communicate with
* the connected retimers.
*/
if (usb4_port_device_is_offline(port->usb4))
return;
tb_port_dbg(port, "disabling sideband transactions\n");
for (i = TB_MAX_RETIMER_INDEX; i >= 1; i--)
usb4_port_retimer_unset_inbound_sbtx(port, i);
}
static ssize_t nvm_authenticate_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct tb_retimer *rt = tb_to_retimer(dev);
int val, ret;
pm_runtime_get_sync(&rt->dev);
if (!mutex_trylock(&rt->tb->lock)) {
ret = restart_syscall();
goto exit_rpm;
}
if (!rt->nvm) {
ret = -EAGAIN;
goto exit_unlock;
}
ret = kstrtoint(buf, 10, &val);
if (ret)
goto exit_unlock;
/* Always clear status */
rt->auth_status = 0;
if (val) {
/*
* When NVM authentication starts the retimer is not
* accessible so calling tb_retimer_unset_inbound_sbtx()
* will fail and therefore we do not call it. Exception
* is when the validation fails or we only write the new
* NVM image without authentication.
*/
tb_retimer_set_inbound_sbtx(rt->port);
if (val == AUTHENTICATE_ONLY) {
ret = tb_retimer_nvm_authenticate(rt, true);
} else {
if (!rt->nvm->flushed) {
if (!rt->nvm->buf) {
ret = -EINVAL;
goto exit_unlock;
}
ret = tb_retimer_nvm_validate_and_write(rt);
if (ret || val == WRITE_ONLY)
goto exit_unlock;
}
if (val == WRITE_AND_AUTHENTICATE)
ret = tb_retimer_nvm_authenticate(rt, false);
}
}
exit_unlock:
if (ret || val == WRITE_ONLY)
tb_retimer_unset_inbound_sbtx(rt->port);
mutex_unlock(&rt->tb->lock);
exit_rpm:
pm_runtime_mark_last_busy(&rt->dev);
pm_runtime_put_autosuspend(&rt->dev);
if (ret)
return ret;
return count;
}
static DEVICE_ATTR_RW(nvm_authenticate);
static ssize_t nvm_version_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct tb_retimer *rt = tb_to_retimer(dev);
int ret;
if (!mutex_trylock(&rt->tb->lock))
return restart_syscall();
if (!rt->nvm)
ret = -EAGAIN;
else
ret = sysfs_emit(buf, "%x.%x\n", rt->nvm->major, rt->nvm->minor);
mutex_unlock(&rt->tb->lock);
return ret;
}
static DEVICE_ATTR_RO(nvm_version);
static ssize_t vendor_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct tb_retimer *rt = tb_to_retimer(dev);
return sysfs_emit(buf, "%#x\n", rt->vendor);
}
static DEVICE_ATTR_RO(vendor);
static struct attribute *retimer_attrs[] = {
&dev_attr_device.attr,
&dev_attr_nvm_authenticate.attr,
&dev_attr_nvm_version.attr,
&dev_attr_vendor.attr,
NULL
};
static const struct attribute_group retimer_group = {
.attrs = retimer_attrs,
};
static const struct attribute_group *retimer_groups[] = {
&retimer_group,
NULL
};
static void tb_retimer_release(struct device *dev)
{
struct tb_retimer *rt = tb_to_retimer(dev);
kfree(rt);
}
struct device_type tb_retimer_type = {
.name = "thunderbolt_retimer",
.groups = retimer_groups,
.release = tb_retimer_release,
};
static int tb_retimer_add(struct tb_port *port, u8 index, u32 auth_status)
{
struct tb_retimer *rt;
u32 vendor, device;
int ret;
ret = usb4_port_retimer_read(port, index, USB4_SB_VENDOR_ID, &vendor,
sizeof(vendor));
if (ret) {
if (ret != -ENODEV)
tb_port_warn(port, "failed read retimer VendorId: %d\n", ret);
return ret;
}
ret = usb4_port_retimer_read(port, index, USB4_SB_PRODUCT_ID, &device,
sizeof(device));
if (ret) {
if (ret != -ENODEV)
tb_port_warn(port, "failed read retimer ProductId: %d\n", ret);
return ret;
}
/*
* Check that it supports NVM operations. If not then don't add
* the device at all.
*/
ret = usb4_port_retimer_nvm_sector_size(port, index);
if (ret < 0)
return ret;
rt = kzalloc(sizeof(*rt), GFP_KERNEL);
if (!rt)
return -ENOMEM;
rt->index = index;
rt->vendor = vendor;
rt->device = device;
rt->auth_status = auth_status;
rt->port = port;
rt->tb = port->sw->tb;
rt->dev.parent = &port->usb4->dev;
rt->dev.bus = &tb_bus_type;
rt->dev.type = &tb_retimer_type;
dev_set_name(&rt->dev, "%s:%u.%u", dev_name(&port->sw->dev),
port->port, index);
ret = device_register(&rt->dev);
if (ret) {
dev_err(&rt->dev, "failed to register retimer: %d\n", ret);
put_device(&rt->dev);
return ret;
}
ret = tb_retimer_nvm_add(rt);
if (ret) {
dev_err(&rt->dev, "failed to add NVM devices: %d\n", ret);
device_unregister(&rt->dev);
return ret;
}
dev_info(&rt->dev, "new retimer found, vendor=%#x device=%#x\n",
rt->vendor, rt->device);
pm_runtime_no_callbacks(&rt->dev);
pm_runtime_set_active(&rt->dev);
pm_runtime_enable(&rt->dev);
pm_runtime_set_autosuspend_delay(&rt->dev, TB_AUTOSUSPEND_DELAY);
pm_runtime_mark_last_busy(&rt->dev);
pm_runtime_use_autosuspend(&rt->dev);
return 0;
}
static void tb_retimer_remove(struct tb_retimer *rt)
{
dev_info(&rt->dev, "retimer disconnected\n");
tb_nvm_free(rt->nvm);
device_unregister(&rt->dev);
}
struct tb_retimer_lookup {
const struct tb_port *port;
u8 index;
};
static int retimer_match(struct device *dev, void *data)
{
const struct tb_retimer_lookup *lookup = data;
struct tb_retimer *rt = tb_to_retimer(dev);
return rt && rt->port == lookup->port && rt->index == lookup->index;
}
static struct tb_retimer *tb_port_find_retimer(struct tb_port *port, u8 index)
{
struct tb_retimer_lookup lookup = { .port = port, .index = index };
struct device *dev;
dev = device_find_child(&port->usb4->dev, &lookup, retimer_match);
if (dev)
return tb_to_retimer(dev);
return NULL;
}
/**
* tb_retimer_scan() - Scan for on-board retimers under port
* @port: USB4 port to scan
* @add: If true also registers found retimers
*
* Brings the sideband into a state where retimers can be accessed.
* Then Tries to enumerate on-board retimers connected to @port. Found
* retimers are registered as children of @port if @add is set. Does
* not scan for cable retimers for now.
*/
int tb_retimer_scan(struct tb_port *port, bool add)
{
u32 status[TB_MAX_RETIMER_INDEX + 1] = {};
int ret, i, last_idx = 0;
/*
* Send broadcast RT to make sure retimer indices facing this
* port are set.
*/
ret = usb4_port_enumerate_retimers(port);
if (ret)
return ret;
/*
* Immediately after sending enumerate retimers read the
* authentication status of each retimer.
*/
tb_retimer_nvm_authenticate_status(port, status);
/*
* Enable sideband channel for each retimer. We can do this
* regardless whether there is device connected or not.
*/
tb_retimer_set_inbound_sbtx(port);
for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++) {
/*
* Last retimer is true only for the last on-board
* retimer (the one connected directly to the Type-C
* port).
*/
ret = usb4_port_retimer_is_last(port, i);
if (ret > 0)
last_idx = i;
else if (ret < 0)
break;
}
tb_retimer_unset_inbound_sbtx(port);
if (!last_idx)
return 0;
/* Add on-board retimers if they do not exist already */
ret = 0;
for (i = 1; i <= last_idx; i++) {
struct tb_retimer *rt;
rt = tb_port_find_retimer(port, i);
if (rt) {
put_device(&rt->dev);
} else if (add) {
ret = tb_retimer_add(port, i, status[i]);
if (ret && ret != -EOPNOTSUPP)
break;
}
}
return ret;
}
static int remove_retimer(struct device *dev, void *data)
{
struct tb_retimer *rt = tb_to_retimer(dev);
struct tb_port *port = data;
if (rt && rt->port == port)
tb_retimer_remove(rt);
return 0;
}
/**
* tb_retimer_remove_all() - Remove all retimers under port
* @port: USB4 port whose retimers to remove
*
* This removes all previously added retimers under @port.
*/
void tb_retimer_remove_all(struct tb_port *port)
{
struct usb4_port *usb4;
usb4 = port->usb4;
if (usb4)
device_for_each_child_reverse(&usb4->dev, port,
remove_retimer);
}