Re: [PATCH 2/2] thunderbolt: Add support for authenticate on disconnect

From: Mika Westerberg
Date: Mon Jun 22 2020 - 12:52:39 EST

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In reply to: Mario Limonciello: "[PATCH 2/2] thunderbolt: Add support for authenticate on disconnect"
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On Mon, Jun 22, 2020 at 09:30:35AM -0500, Mario Limonciello wrote:
> Some external devices can support completing thunderbolt authentication
> when they are unplugged. For this to work though, the link controller must
> remain operational.
>
> The only device known to support this right now is the Dell WD19TB, so add
> a quirk for this.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxxx>
> ---
> .../ABI/testing/sysfs-bus-thunderbolt | 13 ++++++
> drivers/thunderbolt/Makefile | 1 +
> drivers/thunderbolt/eeprom.c | 2 +
> drivers/thunderbolt/lc.c | 14 +++++++
> drivers/thunderbolt/quirks.c | 38 +++++++++++++++++
> drivers/thunderbolt/switch.c | 42 +++++++++++++++++--
> drivers/thunderbolt/tb-quirks.h | 16 +++++++
> drivers/thunderbolt/tb.h | 3 ++
> drivers/thunderbolt/tb_regs.h | 1 +
> 9 files changed, 126 insertions(+), 4 deletions(-)
> create mode 100644 drivers/thunderbolt/quirks.c
> create mode 100644 drivers/thunderbolt/tb-quirks.h
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-thunderbolt b/Documentation/ABI/testing/sysfs-bus-thunderbolt
> index 26b15cbc9881..30798f9a8f59 100644
> --- a/Documentation/ABI/testing/sysfs-bus-thunderbolt
> +++ b/Documentation/ABI/testing/sysfs-bus-thunderbolt
> @@ -243,3 +243,16 @@ KernelVersion: 4.15
> Contact: thunderbolt-software@xxxxxxxxxxxx
> Description: This contains XDomain service specific settings as
> bitmask. Format: %x
> +
> +What: /sys/bus/thunderbolt/devices/.../nvm_authenticate_on_disconnect
> +Date: August 2020
> +KernelVersion: 5.9
> +Contact: thunderbolt-software@xxxxxxxxxxxx

I think you can use your email address here instead.

> +Description: For supported devices, automatically authenticate the new Thunderbolt
> + image when the device is disconnected from the host system.
> +
> + This file will accept writing values "1" or "2"
> + - Writing "1" will flush the image to the storage
> + area and prepare the device for authentication on disconnect.
> + - Writing "2" will only flush the image to the storage
> + area.

Also here it does the basic image validation so probably good to
mention.

> diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile
> index eae28dd45250..013c5564565a 100644
> --- a/drivers/thunderbolt/Makefile
> +++ b/drivers/thunderbolt/Makefile
> @@ -2,3 +2,4 @@
> obj-${CONFIG_USB4} := thunderbolt.o
> thunderbolt-objs := nhi.o nhi_ops.o ctl.o tb.o switch.o cap.o path.o tunnel.o eeprom.o
> thunderbolt-objs += domain.o dma_port.o icm.o property.o xdomain.o lc.o tmu.o usb4.o
> +thunderbolt-objs += quirks.o
> diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c
> index b451a5aa90b5..32838c016c4f 100644
> --- a/drivers/thunderbolt/eeprom.c
> +++ b/drivers/thunderbolt/eeprom.c
> @@ -10,6 +10,7 @@
> #include <linux/property.h>
> #include <linux/slab.h>
> #include "tb.h"
> +#include "tb-quirks.h"
>
> /**
> * tb_eeprom_ctl_write() - write control word
> @@ -599,6 +600,7 @@ int tb_drom_read(struct tb_switch *sw)
> sw->uid = header->uid;
> sw->vendor = header->vendor_id;
> sw->device = header->model_id;
> + check_tbt_quirks(sw);
>
> crc = tb_crc32(sw->drom + TB_DROM_DATA_START, header->data_len);
> if (crc != header->data_crc32) {
> diff --git a/drivers/thunderbolt/lc.c b/drivers/thunderbolt/lc.c
> index bd44d50246d2..45d2a1de2069 100644
> --- a/drivers/thunderbolt/lc.c
> +++ b/drivers/thunderbolt/lc.c
> @@ -366,3 +366,17 @@ int tb_lc_dp_sink_dealloc(struct tb_switch *sw, struct tb_port *in)
> tb_port_dbg(in, "sink %d de-allocated\n", sink);
> return 0;
> }
> +
> +/**
> + * lc_force_power() - Force powers a ridge

Maybe "Forces LC to be powered on" or similar?

> + * @sw: thunderbolt switch
> + *
> + * This is useful to let authentication cycle pass even without
> + * a Thunderbolt link present

Add "." at the end of the sentence.

> + */
> +int lc_force_power(struct tb_switch *sw)

Also tb_lc_force_power() or so to follow the conventions used in the
driver.

> +{
> + u32 in = 0xFFFF;

I prefer 0xffff instead.

> +
> + return tb_sw_write(sw, &in, TB_CFG_SWITCH, TB_LC_POWER, 1);
> +}
> diff --git a/drivers/thunderbolt/quirks.c b/drivers/thunderbolt/quirks.c
> new file mode 100644
> index 000000000000..b9c5cfb97645
> --- /dev/null
> +++ b/drivers/thunderbolt/quirks.c
> @@ -0,0 +1,38 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Thunderbolt driver - quirks
> + *
> + * Copyright (c) 2020 Mario Limonciello <mario.limonciello@xxxxxxxx>
> + */
> +
> +#include "tb.h"
> +#include "tb-quirks.h"
> +
> +static void quirk_force_power_link(struct tb_switch *sw)
> +{
> + sw->quirks |= QUIRK_FORCE_POWER_LINK_CONTROLLER;
> +}
> +
> +struct tbt_quirk {

tb_quirk please.

> + u16 vendor;
> + u16 device;
> + void (*hook)(struct tb_switch *sw);
> +};
> +
> +static struct tbt_quirk tbt_quirks[] = {

const?

> + /* Dell WD19TB supports self-authentication on unplug */
> + { 0x00d4, 0xb070, quirk_force_power_link },
> +};
> +
> +void check_tbt_quirks(struct tb_switch *sw)

Let's call it

tb_check_quirks() or tb_detect_quirks() following USB.

> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(tbt_quirks); i++) {
> + struct tbt_quirk *q = &tbt_quirks[i];
> +
> + if (sw->device == q->device &&
> + sw->vendor == q->vendor)

I think you can write it like this:

if (sw->device == q->device && sw->vendor == q->vendor)

> + q->hook(sw);
> + }
> +}
> diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
> index 4c476a58db38..0576fe7c0054 100644
> --- a/drivers/thunderbolt/switch.c
> +++ b/drivers/thunderbolt/switch.c
> @@ -16,6 +16,7 @@
> #include <linux/vmalloc.h>
>
> #include "tb.h"
> +#include "tb-quirks.h"
>
> /* Switch NVM support */
>
> @@ -1542,8 +1543,8 @@ static ssize_t nvm_authenticate_show(struct device *dev,
> return sprintf(buf, "%#x\n", status);
> }
>
> -static ssize_t nvm_authenticate_store(struct device *dev,
> - struct device_attribute *attr, const char *buf, size_t count)
> +static ssize_t nvm_authenticate_sysfs(struct device *dev, const char *buf,
> + bool disconnect)
> {
> struct tb_switch *sw = tb_to_switch(dev);
> int val;
> @@ -1581,8 +1582,12 @@ static ssize_t nvm_authenticate_store(struct device *dev,
> goto exit_unlock;
> }
> if (val == WRITE_AND_AUTHENTICATE) {
> - sw->nvm->authenticating = true;
> - ret = nvm_authenticate(sw);
> + if (disconnect) {
> + ret = lc_force_power(sw);
> + } else {
> + sw->nvm->authenticating = true;
> + ret = nvm_authenticate(sw);
> + }
> }
> }
>
> @@ -1592,12 +1597,36 @@ static ssize_t nvm_authenticate_store(struct device *dev,
> pm_runtime_mark_last_busy(&sw->dev);
> pm_runtime_put_autosuspend(&sw->dev);
>
> + return ret;
> +}
> +
> +static ssize_t nvm_authenticate_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t count)
> +{
> + int ret = nvm_authenticate_sysfs(dev, buf, false);
> if (ret)
> return ret;
> return count;
> }
> static DEVICE_ATTR_RW(nvm_authenticate);
>
> +static ssize_t nvm_authenticate_on_disconnect_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + return nvm_authenticate_show(dev, attr, buf);
> +}
> +
> +static ssize_t nvm_authenticate_on_disconnect_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t count)
> +{
> + int ret = nvm_authenticate_sysfs(dev, buf, true);
> +
> + if (ret)
> + return ret;
> + return count;

Hmm,

perhaps like this:

int ret;

ret = nvm_authenticate_sysfs(dev, buf, true);
return ret ? ret : count;

> +}
> +static DEVICE_ATTR_RW(nvm_authenticate_on_disconnect);
> +
> static ssize_t nvm_version_show(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> @@ -1655,6 +1684,7 @@ static struct attribute *switch_attrs[] = {
> &dev_attr_generation.attr,
> &dev_attr_key.attr,
> &dev_attr_nvm_authenticate.attr,
> + &dev_attr_nvm_authenticate_on_disconnect.attr,
> &dev_attr_nvm_version.attr,
> &dev_attr_rx_speed.attr,
> &dev_attr_rx_lanes.attr,
> @@ -1709,6 +1739,10 @@ static umode_t switch_attr_is_visible(struct kobject *kobj,
> if (tb_route(sw))
> return attr->mode;
> return 0;
> + } else if (attr == &dev_attr_nvm_authenticate_on_disconnect.attr) {
> + if (sw->quirks & QUIRK_FORCE_POWER_LINK_CONTROLLER)
> + return attr->mode;
> + return 0;
> }
>
> return sw->safe_mode ? 0 : attr->mode;
> diff --git a/drivers/thunderbolt/tb-quirks.h b/drivers/thunderbolt/tb-quirks.h
> new file mode 100644
> index 000000000000..6b644eaaac40
> --- /dev/null
> +++ b/drivers/thunderbolt/tb-quirks.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Thunderbolt driver - quirks
> + *
> + * Copyright (c) 2020 Mario Limonciello <mario.limonciello@xxxxxxxx>
> + */
> +
> +
> +#ifndef _TB_QUIRKS
> +#define _TB_QUIRKS
> +
> +#define QUIRK_FORCE_POWER_LINK_CONTROLLER (1<<1)
> +
> +void check_tbt_quirks(struct tb_switch *sw);

I think we can put these two lines into tb.h for now.

> +
> +#endif
> diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
> index 222ec19737fa..22937be69a1f 100644
> --- a/drivers/thunderbolt/tb.h
> +++ b/drivers/thunderbolt/tb.h
> @@ -118,6 +118,7 @@ struct tb_switch_tmu {
> * @depth: Depth in the chain this switch is connected (ICM only)
> * @rpm_complete: Completion used to wait for runtime resume to
> * complete (ICM only)
> + * @quirks: Quirks used for this Thunderbolt switch
> *
> * When the switch is being added or removed to the domain (other
> * switches) you need to have domain lock held.
> @@ -155,6 +156,7 @@ struct tb_switch {
> u8 link;
> u8 depth;
> struct completion rpm_complete;
> + unsigned long quirks;
> };
>
> /**
> @@ -784,6 +786,7 @@ bool tb_lc_lane_bonding_possible(struct tb_switch *sw);
> bool tb_lc_dp_sink_query(struct tb_switch *sw, struct tb_port *in);
> int tb_lc_dp_sink_alloc(struct tb_switch *sw, struct tb_port *in);
> int tb_lc_dp_sink_dealloc(struct tb_switch *sw, struct tb_port *in);
> +int lc_force_power(struct tb_switch *sw);
>
> static inline int tb_route_length(u64 route)
> {
> diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
> index c29c5075525a..9a2fab9c5346 100644
> --- a/drivers/thunderbolt/tb_regs.h
> +++ b/drivers/thunderbolt/tb_regs.h
> @@ -379,6 +379,7 @@ struct tb_regs_hop {
> #define TB_LC_SNK_ALLOCATION_SNK1_SHIFT 4
> #define TB_LC_SNK_ALLOCATION_SNK1_MASK GENMASK(7, 4)
> #define TB_LC_SNK_ALLOCATION_SNK1_CM 0x1
> +#define TB_LC_POWER 0x740
>
> /* Link controller registers */
> #define TB_LC_PORT_ATTR 0x8d
> --
> 2.25.1

Next message: Bjorn Helgaas: "Re: [PATCH v1 1/1] pci: controller: cadence: fix wrong path in comment"
Previous message: Sedat Dilek: "Re: [PATCH 5.7] x86/crypto: aesni: Fix build with LLVM_IAS=1"
In reply to: Mario Limonciello: "[PATCH 2/2] thunderbolt: Add support for authenticate on disconnect"
Next in thread: Mario.Limonciello: "RE: [PATCH 0/2] Allow breaking up Thunderbolt/USB4 updates"
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