2019-12-13 08:47:48

by Stanley Chu

[permalink] [raw]
Subject: [PATCH v1 0/4] scsi: ufs-mediatek: provide power management

The patch set provides power management on MediaTek Chipsets by

1. Introduce reference clock control
2. Configure customized auto-hibernate timer
3. Enable clk-gating with customized delayed timer value

Stanley Chu (4):
scsi: ufs-mediatek: introduce reference clock control
scsi: ufs: export ufshcd_auto_hibern8_update for vendor usage
scsi: ufs-mediatek: configure customized auto-hibern8 timer
scsi: ufs-mediatek: configure and enable clk-gating

drivers/scsi/ufs/ufs-mediatek.c | 93 +++++++++++++++++++++++++++++++--
drivers/scsi/ufs/ufs-mediatek.h | 20 ++++++-
drivers/scsi/ufs/ufs-sysfs.c | 20 -------
drivers/scsi/ufs/ufshcd.c | 18 +++++++
drivers/scsi/ufs/ufshcd.h | 1 +
5 files changed, 126 insertions(+), 26 deletions(-)

--
2.18.0


2019-12-13 08:54:08

by Stanley Chu

[permalink] [raw]
Subject: [PATCH v1 1/4] scsi: ufs-mediatek: introduce reference clock control

Introduce reference clock control in MediaTek Chipset in order
to disable it if it is not necessary by UFS device to save system power.

Currently reference clock can be disabled during system suspend, runtime
suspend and clock-gating after link enters hibernate state.

Signed-off-by: Stanley Chu <[email protected]>
---
drivers/scsi/ufs/ufs-mediatek.c | 64 ++++++++++++++++++++++++++++++---
drivers/scsi/ufs/ufs-mediatek.h | 20 +++++++++--
2 files changed, 78 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 6a3ec11b16db..690483c78212 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -18,6 +18,11 @@
#include "unipro.h"
#include "ufs-mediatek.h"

+#define ufs_mtk_ref_clk_notify(on, res) \
+ arm_smccc_smc(MTK_SIP_UFS_CONTROL, \
+ UFS_MTK_SIP_REF_CLK_NOTIFICATION, \
+ on, 0, 0, 0, 0, 0, &(res))
+
static void ufs_mtk_cfg_unipro_cg(struct ufs_hba *hba, bool enable)
{
u32 tmp;
@@ -83,6 +88,49 @@ static int ufs_mtk_bind_mphy(struct ufs_hba *hba)
return err;
}

+static int ufs_mtk_setup_ref_clk(struct ufs_hba *hba, bool on)
+{
+ struct ufs_mtk_host *host = ufshcd_get_variant(hba);
+ struct arm_smccc_res res;
+ unsigned long timeout;
+ u32 value;
+
+ if (host->ref_clk_enabled == on)
+ return 0;
+
+ if (on) {
+ ufs_mtk_ref_clk_notify(on, res);
+ ufshcd_writel(hba, REFCLK_REQUEST, REG_UFS_REFCLK_CTRL);
+ } else {
+ ufshcd_writel(hba, REFCLK_RELEASE, REG_UFS_REFCLK_CTRL);
+ }
+
+ /* Wait for ack */
+ timeout = jiffies + msecs_to_jiffies(REFCLK_REQ_TIMEOUT_MS);
+ do {
+ value = ufshcd_readl(hba, REG_UFS_REFCLK_CTRL);
+
+ /* Wait until ack bit equals to req bit */
+ if (((value & REFCLK_ACK) >> 1) == (value & REFCLK_REQUEST))
+ goto out;
+
+ usleep_range(100, 200);
+ } while (time_before(jiffies, timeout));
+
+ dev_err(hba->dev, "missing ack of refclk req, reg: 0x%x\n", value);
+
+ ufs_mtk_ref_clk_notify(host->ref_clk_enabled, res);
+
+ return -ETIMEDOUT;
+
+out:
+ host->ref_clk_enabled = on;
+ if (!on)
+ ufs_mtk_ref_clk_notify(on, res);
+
+ return 0;
+}
+
/**
* ufs_mtk_setup_clocks - enables/disable clocks
* @hba: host controller instance
@@ -107,12 +155,16 @@ static int ufs_mtk_setup_clocks(struct ufs_hba *hba, bool on,

switch (status) {
case PRE_CHANGE:
- if (!on)
+ if (!on) {
+ ufs_mtk_setup_ref_clk(hba, on);
ret = phy_power_off(host->mphy);
+ }
break;
case POST_CHANGE:
- if (on)
+ if (on) {
ret = phy_power_on(host->mphy);
+ ufs_mtk_setup_ref_clk(hba, on);
+ }
break;
}

@@ -299,8 +351,10 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
{
struct ufs_mtk_host *host = ufshcd_get_variant(hba);

- if (ufshcd_is_link_hibern8(hba))
+ if (ufshcd_is_link_hibern8(hba)) {
phy_power_off(host->mphy);
+ ufs_mtk_setup_ref_clk(hba, false);
+ }

return 0;
}
@@ -309,8 +363,10 @@ static int ufs_mtk_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
{
struct ufs_mtk_host *host = ufshcd_get_variant(hba);

- if (ufshcd_is_link_hibern8(hba))
+ if (ufshcd_is_link_hibern8(hba)) {
+ ufs_mtk_setup_ref_clk(hba, true);
phy_power_on(host->mphy);
+ }

return 0;
}
diff --git a/drivers/scsi/ufs/ufs-mediatek.h b/drivers/scsi/ufs/ufs-mediatek.h
index b03f601d3a9e..14f8a8357c09 100644
--- a/drivers/scsi/ufs/ufs-mediatek.h
+++ b/drivers/scsi/ufs/ufs-mediatek.h
@@ -6,7 +6,21 @@
#ifndef _UFS_MEDIATEK_H
#define _UFS_MEDIATEK_H

-#include <linux/bitops.h>
+/*
+ * Vendor specific UFSHCI Registers
+ */
+#define REG_UFS_REFCLK_CTRL 0x144
+
+/*
+ * Ref-clk control
+ *
+ * Values for register REG_UFS_REFCLK_CTRL
+ */
+#define REFCLK_RELEASE 0x0
+#define REFCLK_REQUEST BIT(0)
+#define REFCLK_ACK BIT(1)
+
+#define REFCLK_REQ_TIMEOUT_MS 3

/*
* Vendor specific pre-defined parameters
@@ -34,7 +48,8 @@
/*
* SiP commands
*/
-#define UFS_MTK_SIP_DEVICE_RESET BIT(1)
+#define UFS_MTK_SIP_DEVICE_RESET BIT(1)
+#define UFS_MTK_SIP_REF_CLK_NOTIFICATION BIT(3)

/*
* VS_DEBUGCLOCKENABLE
@@ -55,6 +70,7 @@ enum {
struct ufs_mtk_host {
struct ufs_hba *hba;
struct phy *mphy;
+ bool ref_clk_enabled;
};

#endif /* !_UFS_MEDIATEK_H */
--
2.18.0

2019-12-13 09:12:30

by Stanley Chu

[permalink] [raw]
Subject: [PATCH v1 4/4] scsi: ufs-mediatek: configure and enable clk-gating

Enable clk-gating with customized delayed timer value in
MediaTek Chipsets.

Signed-off-by: Stanley Chu <[email protected]>
---
drivers/scsi/ufs/ufs-mediatek.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 71e2e0e4ea11..282ad06ec846 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -205,6 +205,9 @@ static int ufs_mtk_init(struct ufs_hba *hba)
/* Enable runtime autosuspend */
hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;

+ /* Enable clock-gating */
+ hba->caps |= UFSHCD_CAP_CLK_GATING;
+
/*
* ufshcd_vops_init() is invoked after
* ufshcd_setup_clock(true) in ufshcd_hba_init() thus
@@ -293,6 +296,23 @@ static int ufs_mtk_pre_link(struct ufs_hba *hba)
return ret;
}

+static void ufs_mtk_setup_clk_gating(struct ufs_hba *hba)
+{
+ unsigned long flags;
+ u32 ah_ms;
+
+ if (ufshcd_is_clkgating_allowed(hba)) {
+ if (ufshcd_is_auto_hibern8_supported(hba) && hba->ahit)
+ ah_ms = FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK,
+ hba->ahit);
+ else
+ ah_ms = 10;
+ spin_lock_irqsave(hba->host->host_lock, flags);
+ hba->clk_gating.delay_ms = ah_ms + 5;
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+ }
+}
+
static int ufs_mtk_post_link(struct ufs_hba *hba)
{
/* disable device LCC */
@@ -308,6 +328,8 @@ static int ufs_mtk_post_link(struct ufs_hba *hba)
FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3));
}

+ ufs_mtk_setup_clk_gating(hba);
+
return 0;
}

--
2.18.0

2019-12-13 09:36:27

by Stanley Chu

[permalink] [raw]
Subject: [PATCH v1 3/4] scsi: ufs-mediatek: configure customized auto-hibern8 timer

Configure customized auto-hibern8 timer in MediaTek Chipsets.

Signed-off-by: Stanley Chu <[email protected]>
---
drivers/scsi/ufs/ufs-mediatek.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 690483c78212..71e2e0e4ea11 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -7,6 +7,7 @@
*/

#include <linux/arm-smccc.h>
+#include <linux/bitfield.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/phy/phy.h>
@@ -300,6 +301,13 @@ static int ufs_mtk_post_link(struct ufs_hba *hba)
/* enable unipro clock gating feature */
ufs_mtk_cfg_unipro_cg(hba, true);

+ /* configure auto-hibern8 timer to 10ms */
+ if (ufshcd_is_auto_hibern8_supported(hba)) {
+ ufshcd_auto_hibern8_update(hba,
+ FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK, 10) |
+ FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3));
+ }
+
return 0;
}

--
2.18.0

2019-12-19 18:19:58

by Alim Akhtar

[permalink] [raw]
Subject: Re: [PATCH v1 1/4] scsi: ufs-mediatek: introduce reference clock control

On Fri, Dec 13, 2019 at 2:23 PM Stanley Chu <[email protected]> wrote:
>
> Introduce reference clock control in MediaTek Chipset in order
> to disable it if it is not necessary by UFS device to save system power.
>
> Currently reference clock can be disabled during system suspend, runtime
> suspend and clock-gating after link enters hibernate state.
>
> Signed-off-by: Stanley Chu <[email protected]>

Reviewed-by: Alim Akhtar <[email protected]>

> ---
> drivers/scsi/ufs/ufs-mediatek.c | 64 ++++++++++++++++++++++++++++++---
> drivers/scsi/ufs/ufs-mediatek.h | 20 +++++++++--
> 2 files changed, 78 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
> index 6a3ec11b16db..690483c78212 100644
> --- a/drivers/scsi/ufs/ufs-mediatek.c
> +++ b/drivers/scsi/ufs/ufs-mediatek.c
> @@ -18,6 +18,11 @@
> #include "unipro.h"
> #include "ufs-mediatek.h"
>
> +#define ufs_mtk_ref_clk_notify(on, res) \
> + arm_smccc_smc(MTK_SIP_UFS_CONTROL, \
> + UFS_MTK_SIP_REF_CLK_NOTIFICATION, \
> + on, 0, 0, 0, 0, 0, &(res))
> +
> static void ufs_mtk_cfg_unipro_cg(struct ufs_hba *hba, bool enable)
> {
> u32 tmp;
> @@ -83,6 +88,49 @@ static int ufs_mtk_bind_mphy(struct ufs_hba *hba)
> return err;
> }
>
> +static int ufs_mtk_setup_ref_clk(struct ufs_hba *hba, bool on)
> +{
> + struct ufs_mtk_host *host = ufshcd_get_variant(hba);
> + struct arm_smccc_res res;
> + unsigned long timeout;
> + u32 value;
> +
> + if (host->ref_clk_enabled == on)
> + return 0;
> +
> + if (on) {
> + ufs_mtk_ref_clk_notify(on, res);
> + ufshcd_writel(hba, REFCLK_REQUEST, REG_UFS_REFCLK_CTRL);
> + } else {
> + ufshcd_writel(hba, REFCLK_RELEASE, REG_UFS_REFCLK_CTRL);
> + }
> +
> + /* Wait for ack */
> + timeout = jiffies + msecs_to_jiffies(REFCLK_REQ_TIMEOUT_MS);
> + do {
> + value = ufshcd_readl(hba, REG_UFS_REFCLK_CTRL);
> +
> + /* Wait until ack bit equals to req bit */
> + if (((value & REFCLK_ACK) >> 1) == (value & REFCLK_REQUEST))
> + goto out;
> +
> + usleep_range(100, 200);
> + } while (time_before(jiffies, timeout));
> +
> + dev_err(hba->dev, "missing ack of refclk req, reg: 0x%x\n", value);
> +
> + ufs_mtk_ref_clk_notify(host->ref_clk_enabled, res);
> +
> + return -ETIMEDOUT;
> +
> +out:
> + host->ref_clk_enabled = on;
> + if (!on)
> + ufs_mtk_ref_clk_notify(on, res);
> +
> + return 0;
> +}
> +
> /**
> * ufs_mtk_setup_clocks - enables/disable clocks
> * @hba: host controller instance
> @@ -107,12 +155,16 @@ static int ufs_mtk_setup_clocks(struct ufs_hba *hba, bool on,
>
> switch (status) {
> case PRE_CHANGE:
> - if (!on)
> + if (!on) {
> + ufs_mtk_setup_ref_clk(hba, on);
> ret = phy_power_off(host->mphy);
> + }
> break;
> case POST_CHANGE:
> - if (on)
> + if (on) {
> ret = phy_power_on(host->mphy);
> + ufs_mtk_setup_ref_clk(hba, on);
> + }
> break;
> }
>
> @@ -299,8 +351,10 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
> {
> struct ufs_mtk_host *host = ufshcd_get_variant(hba);
>
> - if (ufshcd_is_link_hibern8(hba))
> + if (ufshcd_is_link_hibern8(hba)) {
> phy_power_off(host->mphy);
> + ufs_mtk_setup_ref_clk(hba, false);
> + }
>
> return 0;
> }
> @@ -309,8 +363,10 @@ static int ufs_mtk_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
> {
> struct ufs_mtk_host *host = ufshcd_get_variant(hba);
>
> - if (ufshcd_is_link_hibern8(hba))
> + if (ufshcd_is_link_hibern8(hba)) {
> + ufs_mtk_setup_ref_clk(hba, true);
> phy_power_on(host->mphy);
> + }
>
> return 0;
> }
> diff --git a/drivers/scsi/ufs/ufs-mediatek.h b/drivers/scsi/ufs/ufs-mediatek.h
> index b03f601d3a9e..14f8a8357c09 100644
> --- a/drivers/scsi/ufs/ufs-mediatek.h
> +++ b/drivers/scsi/ufs/ufs-mediatek.h
> @@ -6,7 +6,21 @@
> #ifndef _UFS_MEDIATEK_H
> #define _UFS_MEDIATEK_H
>
> -#include <linux/bitops.h>
> +/*
> + * Vendor specific UFSHCI Registers
> + */
> +#define REG_UFS_REFCLK_CTRL 0x144
> +
> +/*
> + * Ref-clk control
> + *
> + * Values for register REG_UFS_REFCLK_CTRL
> + */
> +#define REFCLK_RELEASE 0x0
> +#define REFCLK_REQUEST BIT(0)
> +#define REFCLK_ACK BIT(1)
> +
> +#define REFCLK_REQ_TIMEOUT_MS 3
>
> /*
> * Vendor specific pre-defined parameters
> @@ -34,7 +48,8 @@
> /*
> * SiP commands
> */
> -#define UFS_MTK_SIP_DEVICE_RESET BIT(1)
> +#define UFS_MTK_SIP_DEVICE_RESET BIT(1)
> +#define UFS_MTK_SIP_REF_CLK_NOTIFICATION BIT(3)
>
> /*
> * VS_DEBUGCLOCKENABLE
> @@ -55,6 +70,7 @@ enum {
> struct ufs_mtk_host {
> struct ufs_hba *hba;
> struct phy *mphy;
> + bool ref_clk_enabled;
> };
>
> #endif /* !_UFS_MEDIATEK_H */
> --
> 2.18.0



--
Regards,
Alim

2019-12-19 18:27:15

by Alim Akhtar

[permalink] [raw]
Subject: Re: [PATCH v1 3/4] scsi: ufs-mediatek: configure customized auto-hibern8 timer

On Fri, Dec 13, 2019 at 3:04 PM Stanley Chu <[email protected]> wrote:
>
> Configure customized auto-hibern8 timer in MediaTek Chipsets.
>
> Signed-off-by: Stanley Chu <[email protected]>

Reviewed-by: Alim Akhtar <[email protected]>
> ---
> drivers/scsi/ufs/ufs-mediatek.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
> index 690483c78212..71e2e0e4ea11 100644
> --- a/drivers/scsi/ufs/ufs-mediatek.c
> +++ b/drivers/scsi/ufs/ufs-mediatek.c
> @@ -7,6 +7,7 @@
> */
>
> #include <linux/arm-smccc.h>
> +#include <linux/bitfield.h>
> #include <linux/of.h>
> #include <linux/of_address.h>
> #include <linux/phy/phy.h>
> @@ -300,6 +301,13 @@ static int ufs_mtk_post_link(struct ufs_hba *hba)
> /* enable unipro clock gating feature */
> ufs_mtk_cfg_unipro_cg(hba, true);
>
> + /* configure auto-hibern8 timer to 10ms */
> + if (ufshcd_is_auto_hibern8_supported(hba)) {
> + ufshcd_auto_hibern8_update(hba,
> + FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK, 10) |
> + FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3));
> + }
> +
> return 0;
> }
>
> --
> 2.18.0



--
Regards,
Alim

2019-12-19 18:34:50

by Alim Akhtar

[permalink] [raw]
Subject: Re: [PATCH v1 4/4] scsi: ufs-mediatek: configure and enable clk-gating

On Fri, Dec 13, 2019 at 2:42 PM Stanley Chu <[email protected]> wrote:
>
> Enable clk-gating with customized delayed timer value in
> MediaTek Chipsets.
>
> Signed-off-by: Stanley Chu <[email protected]>

Reviewed-by: Alim Akhtar <[email protected]>

> ---
> drivers/scsi/ufs/ufs-mediatek.c | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
> index 71e2e0e4ea11..282ad06ec846 100644
> --- a/drivers/scsi/ufs/ufs-mediatek.c
> +++ b/drivers/scsi/ufs/ufs-mediatek.c
> @@ -205,6 +205,9 @@ static int ufs_mtk_init(struct ufs_hba *hba)
> /* Enable runtime autosuspend */
> hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
>
> + /* Enable clock-gating */
> + hba->caps |= UFSHCD_CAP_CLK_GATING;
> +
> /*
> * ufshcd_vops_init() is invoked after
> * ufshcd_setup_clock(true) in ufshcd_hba_init() thus
> @@ -293,6 +296,23 @@ static int ufs_mtk_pre_link(struct ufs_hba *hba)
> return ret;
> }
>
> +static void ufs_mtk_setup_clk_gating(struct ufs_hba *hba)
> +{
> + unsigned long flags;
> + u32 ah_ms;
> +
> + if (ufshcd_is_clkgating_allowed(hba)) {
> + if (ufshcd_is_auto_hibern8_supported(hba) && hba->ahit)
> + ah_ms = FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK,
> + hba->ahit);
> + else
> + ah_ms = 10;
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + hba->clk_gating.delay_ms = ah_ms + 5;
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> + }
> +}
> +
> static int ufs_mtk_post_link(struct ufs_hba *hba)
> {
> /* disable device LCC */
> @@ -308,6 +328,8 @@ static int ufs_mtk_post_link(struct ufs_hba *hba)
> FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3));
> }
>
> + ufs_mtk_setup_clk_gating(hba);
> +
> return 0;
> }
>
> --
> 2.18.0



--
Regards,
Alim

2019-12-19 23:20:10

by Martin K. Petersen

[permalink] [raw]
Subject: Re: [PATCH v1 0/4] scsi: ufs-mediatek: provide power management


Stanley,

> The patch set provides power management on MediaTek Chipsets by

Had to apply this by hand. Please make sure you prepare patch
submissions against my "queue" branch.

--
Martin K. Petersen Oracle Linux Engineering

2019-12-20 01:26:15

by Stanley Chu

[permalink] [raw]
Subject: Re: [PATCH v1 0/4] scsi: ufs-mediatek: provide power management

Hi Martin,

Thank you so much and sorry for your inconvenience.

I was based on the latest linux-next commit in my submission time. I
will be more careful and use your "queue" branch instead for submission.

BTW, sorry again because this series actually require a header file
present by below patch in another series which was submitted earlier
than this series,

"soc: mediatek: add header for SiP service interface"

Otherwise missing header "include/linux/soc/mediatek/mtk_sip_svc.h" will
cause build error if MediaTek UFS driver is enabled.

Hope "soc: mediatek: add header for SiP service interface" could be
merged soon, or please rollback this series first if build error happens
and wait until above patch is merged.

To prevent this error, I shall merge both series and provide a new
combined series. If you want me to do so, please kindly let me know.
Sorry for this again.

On Thu, 2019-12-19 at 18:17 -0500, Martin K. Petersen wrote:
> Stanley,
>
> > The patch set provides power management on MediaTek Chipsets by
>
> Had to apply this by hand. Please make sure you prepare patch
> submissions against my "queue" branch.
>

Thanks,
Stanley


2019-12-20 02:26:52

by Martin K. Petersen

[permalink] [raw]
Subject: Re: [PATCH v1 0/4] scsi: ufs-mediatek: provide power management


Stanley,

> Otherwise missing header "include/linux/soc/mediatek/mtk_sip_svc.h"
> will cause build error if MediaTek UFS driver is enabled.

Thanks for the heads-up. I obviously don't have an easy way to verify. I
did check after applying to see if there was a way I could trigger a
build of the driver on a non MediaTek platform. But that didn't appear
to be trivial.

--
Martin K. Petersen Oracle Linux Engineering