Memory and Storage - Qualcomm Dragonwing Documentation

The Qualcomm Linux platform supports four primary storage types.

Storage Type	Versions
Universal Flash Storage (UFS)	v2.1, v2.2, v3.1
Embedded Multi-Media Card (eMMC)	v5.1
Non-Volatile Memory Express (NVMe)	v1.3
Secure Digital (SD) Card	v3.0

Configure the device to boot from only one storage source. Using both sources for bootable files may cause system crashes or unpredictable behavior.

UFS Storage

Features

Feature	Description
Lanes	2 lanes supported
Gear	HS Gear 1, 2, 3, and 4
Low-Power Mode	Link hibernate and device sleep
Hot-Plug	Not supported (embedded only)

Kernel Configuration

Configuration	Default	Description
`CONFIG_UFS_FAULT_INJECTION`	No	Injects failure commands for debugging
`CONFIG_SCSI_UFSHCD`	Yes	UFS host control driver
`CONFIG_SCSI_UFSHCD_PLATFORM`	Yes	UFS controller from platform bus
`CONFIG_SCSI_UFS_QCOM`	Yes	Qualcomm-specific PHY and vendor registers
`CONFIG_PHY_QCOM_QMP`	Yes	UFS QMP PHY driver
`CONFIG_SCSI_UFS_BSG`	Yes	UFS BSG device node
`CONFIG_SCSI_UFS_CRYPTO`	Yes	UFS crypto engine

Power Management States

Auto-Hibern8 (AH8) — Transitions PHY link to Hibernate after 150 ms of idle time (adjustable).

cat /sys/devices/platform/soc@0/1d84000.ufs/auto_hibern8

Clock Gating — Gated after 50 ms (max freq) or 10 ms (scaled freq) of idle time. Enabled by default.

cat /sys/devices/platform/soc@0/1d84000.ufs/clkgate_enable
# Disable for debugging:
echo 0 > /sys/devices/platform/soc@0/1d84000.ufs/clkgate_enable

Clock Scaling — Scales up/down based on load threshold. Enabled by default; disabling increases power consumption.

cat /sys/devices/platform/soc@0/1d84000.ufs/clkscale_enable

Runtime Suspend/Resume — Enters suspend after 3 seconds of inactivity. Always enabled, not configurable. System Suspend/Resume — Follows system suspend/resume events. Always enabled, not configurable.

Device Parameters

Parameter	Subnode	Value	Description
`init_speed_params`	EnableHighSpeed	1	Enables high speed mode
	NumGears	4	Maximum gear (3 for UFS 2.x, 4 for UFS 3.1)
	NumLanes	2	Number of lanes
	Rate	2	1=Rate A, 2=Rate B
`perf_speed_params`	EnableHighSpeed	1	High speed in perf mode
	NumGears	4	Maximum gear in perf mode
	NumLanes	2	Lanes in perf mode
	Rate	2	Series in perf mode
`timeout_values`	fDeviceInitTimeout	2500000 μs	Device init timeout
	UTRDPollTimeout	30000000 μs	UTRD timeout
`BatteryThresholdMv`	—	3600	Battery threshold (mV) to move to Gear 1
`LinkStartupRetryCount`	—	5	Link startup retry count
`RefClock`	—	19200000	Reference clock (19.2 MHz)

UFS Provisioning

UFS provisioning creates Logical Unit Numbers (LUNs) on a new UFS device. Device Descriptor Parameters:

Parameter	Description
`bNumberLU`	Number of Logical Units
`bBootEnable`	`00h`: Boot disabled, `01h`: Boot enabled
`bConfigDescrLock`	`0h`: Unlocked, `1h`: Locked (prevents reprovisioning)

Set bConfigDescrLock="0" during development. Set to "1" after finalization to prevent reprovisioning.

LUN Parameters:

Parameter	Description
`LUNum`	Logical Unit Number
`bLUEnable`	`00h`: Disabled, `01h`: Enabled
`bBootLunID`	`00h`: Not bootable, `01h`: Boot LU A, `02h`: Boot LU B
`size_in_kb`	LUN size in KB
`bMemoryType`	`00h`: Normal, `01h`: System code, `02h`: Non-Persistent
`bProvisioningType`	`00h`: Thin provisioning disabled, `02h`: Enabled (TPRZ=0)

Default Partition Layout:

LUN0 — Linux data and filesystem images
LUN1 & LUN2 — Boot WLUN (0xB0) alternates for fail-safe XBL backup
LUN4 — Rest of boot chain
LUN6 & LUN7 — Unused by default

Architecture Diagrams

eMMC Storage

Features

Feature	Description
Speed	DDR50, HS200, HS400, HS400 Enhanced
Sleep Mode	Clock gating and auto suspend
Command Queuing	Multiple simultaneous commands

Device Tree Configuration

Add the following to the &sdhc_1 node in the SoC-specific DTSI file:

&sdhc_1 {
    status = "okay";
    pinctrl-names = "default", "sleep";
    pinctrl-0 = <&sdc1_on>;
    pinctrl-1 = <&sdc1_off>;
    vmmc-supply = <&vreg_l19a_2p9>;
    vqmmc-supply = <&vreg_l12a_1p8>;
};

Power Management

Runtime Suspend — After 50 ms of inactivity; always enabled
System Suspend — Follows system suspend/resume events; always enabled

SD Card Storage

Features

Feature	Description
Bus Width	4-bit mode
Speed	SDR50, SDR104, DDR50
Hot-Plug	Supported

Kernel Configuration

Configuration	Default	Description
`CONFIG_MMC`	Yes	MMC driver
`CONFIG_MMC_SDHCI`	Yes	SDHCI driver
`CONFIG_MMC_CQHCI`	Yes	Command Queue Host Control Interface
`CONFIG_MMC_SDHCI_MSM`	Yes	MSM SDHCI driver
`CONFIG_MMC_BLOCK`	Yes	MMC block driver
`CONFIG_MMC_CRYPTO`	Yes	MMC Crypto Engine

Power Management

Runtime Suspend — After 50 ms of inactivity; always enabled
System Suspend — Follows system suspend/resume events; always enabled

NVMe Storage

Feature	Description
Lanes	4 lanes over PCIe port (PCIe1)
Interface	High-speed serial
Protocol	Optimized for NAND flash and next-gen SSDs

Configuration Guide

Mount File Systems

UFS / eMMC
SD Card
NVMe

mkdir /tmp/data
mount -t ext4 /dev/sda3 /tmp/data
df -a

mkdir sdcard
mkfs.vfat /dev/mmcblk1p1   # Format if needed
mount -t vfat /dev/mmcblk1p1 /sdcard
df -a

# Create partition table
fdisk /dev/nvme0n1
# Follow prompts: n (new), p (primary), accept defaults, w (write)

reboot

mkfs.ext4 /dev/nvme0n1p1
mount /dev/nvme0n1p1 /media
df -a

Power Management Control

# Mount debugfs (required for debug nodes)
mount -t debugfs none /sys/kernel/debug

# UFS Auto-Hibern8
cat /sys/devices/platform/soc@0/1d84000.ufs/auto_hibern8
echo <value_in_us> > /sys/devices/platform/soc@0/1d84000.ufs/auto_hibern8

# UFS Clock Gating
echo 0 > /sys/devices/platform/soc@0/1d84000.ufs/clkgate_enable  # Disable
echo 1 > /sys/devices/platform/soc@0/1d84000.ufs/clkgate_enable  # Enable

# UFS Clock Scaling
echo 0 > /sys/devices/platform/soc@0/1d84000.ufs/clkscale_enable  # Disable
echo 1 > /sys/devices/platform/soc@0/1d84000.ufs/clkscale_enable  # Enable

Troubleshooting

Command Pending in Device

Symptoms:

ufshcd-qcom 1d84000.ufshc: ufshcd_abort: cmd pending in the device. tag = 1

Resolution: Contact UFS device vendor; check device compatibility and power supply stability.

No Response from Device

Symptoms:

ufshcd-qcom 1d84000.ufshc: ufshcd_abort: no response from device. tag = 2, err -110

Resolution: Check physical connections, verify power rails, check PHY initialization.

Physical Adapter / Data Link Error

Symptoms:

ufshcd-qcom 1d84000.ufshc: pa_err_cnt_total=5086, pa_lane_0_err_cnt=3250
ufshcd-qcom 1d84000.ufshc: dl_err_cnt_total=4488, dl_nac_received_err_cnt=289

Diagnosis:

mount -t debugfs none /sys/kernel/debug
cat /sys/kernel/debug/ufshcd/1d84000.ufs/stats

Resolution: Indicates poor signal quality. Check PCB layout, signal integrity, and PHY settings. Contact Qualcomm support for PHY tuning.

High Power Consumption in Active State

Diagnosis:

cat /sys/devices/platform/soc@0/1d84000.ufs/devfreq/1d84000.ufs/cur_freq
cat /sys/devices/platform/soc@0/1d84000.ufs/clkscale_enable

Resolution: Enable clock scaling if disabled; disable WriteBooster if not needed.

High Power Consumption in Sleep State

Diagnosis:

cat /sys/devices/platform/soc@0/1d84000.ufs/power_info/link_state
cat /sys/devices/platform/soc@0/1d84000.ufs/power_info/dev_pm
cat /sys/devices/platform/soc@0/1d84000.ufs/power/runtime_status

Resolution: Adjust PM level; disable HPB/WriteBooster if causing issues; verify VCC/VCCQ/VCCQ2 timing.

Unhandled SMMU Fault

Symptoms:

arm-smmu 15000000.apps-smmu: Unhandled arm-smmu context fault from 1d84000.ufshc!

Resolution: In the ufshc_mem node in the SoC DTSI file, change:

qcom,iommu-dma = "fastmap";

to:

qcom,iommu-dma = "bypass";

Command Reference

UFS Commands

Purpose	Command
Check PA/DL error count	`cat /sys/kernel/debug/ufshcd/1d84000.ufs/stats`
Read current clock frequency	`cat /sys/devices/platform/soc@0/1d84000.ufs/devfreq/1d84000.ufs/cur_freq`
Read device state (active/sleep)	`cat /sys/devices/platform/soc@0/1d84000.ufs/power_info/dev_pm`
Read gear information	`cat /sys/devices/platform/soc@0/1d84000.ufs/power_info/gear`
Read link state (ACTIVE/HIBERN8)	`cat /sys/devices/platform/soc@0/1d84000.ufs/power_info/link_state`
Read runtime status	`cat /sys/devices/platform/soc@0/1d84000.ufs/power/runtime_status`
Read RPM/SPM level	`cat /sys/devices/platform/soc@0/1d84000.ufs/rpm_lvl`

SD Card Commands

Purpose	Command
Read error stats	`cat /sys/kernel/debug/mmc1/err_stats`
Check current clock	`cat /sys/kernel/debug/mmc1/clock`
Read runtime status	`cat /sys/devices/platform/soc@0/8804000.mmc/power/runtime_status`

NVMe Commands

Purpose	Command
View device model	`cat /sys/class/nvme/nvme0/model`
View firmware version	`cat /sys/class/nvme/nvme0/firmware_rev`
View namespace size	`cat /sys/class/nvme/nvme0/nvme0n1/size`

eMMC Commands

Purpose	Command
Error stats	`cat /sys/kernel/debug/mmc0/err_stats`
Current clock	`cat /sys/kernel/debug/mmc0/clock`
Runtime status	`cat /sys/devices/platform/soc@0/7c4000/power/runtime_status`

For eMMC commands, replace the address with the SoC-specific value: IQ-615 and IQ-9075 use 7c4000; IQ-8275 uses 87c4000.

References

EXT4 Filesystem Introduction

​UFS Storage

​Features

​Kernel Configuration

​Power Management States

​Device Parameters

​UFS Provisioning

​Architecture Diagrams

​eMMC Storage

​Features

​Device Tree Configuration

​Power Management

​SD Card Storage

​Features

​Kernel Configuration

​Power Management

​NVMe Storage

​Configuration Guide

​Mount File Systems

​Power Management Control

​Troubleshooting

​Command Reference

​UFS Commands

​SD Card Commands

​NVMe Commands

​eMMC Commands

​References

UFS Storage

Features

Kernel Configuration

Power Management States

Device Parameters

UFS Provisioning

Architecture Diagrams

eMMC Storage

Features

Device Tree Configuration

Power Management

SD Card Storage

Features

Kernel Configuration

Power Management

NVMe Storage

Configuration Guide

Mount File Systems

Power Management Control

Troubleshooting

Command Reference

UFS Commands

SD Card Commands

NVMe Commands

eMMC Commands

References