Re: [PATCH v2 0/2] mtd: devices: Qualcomm SCM storage support

[Junhao Xie]

On 2026/1/29 5:43, Trilok Soni wrote:

> On 1/26/2026 3:44 AM, Junhao Xie wrote:
> > This patch series adds support for accessing storage devices managed by
> > Qualcomm TrustZone firmware via SCM (Secure Channel Manager) by
> > introducing a new MTD driver.
> >
> > On some Qualcomm platforms, firmware or BIOS-related storage (typically
> > SPI NOR flash) is not directly accessible from the non-secure world.
> > All read, write, and erase operations must be performed through SCM
> > interfaces provided by the secure firmware. As a result, existing MTD
> > SPI NOR drivers cannot be used directly on these systems.
> >
> > This series introduces a new MTD device driver that exposes such
> > firmware-managed storage as a standard MTD device in the Linux kernel.
> > The driver is built on top of the existing Qualcomm SCM infrastructure
> > and integrates with the MTD subsystem to provide a uniform interface to
> > userspace.
> >
> > This driver has been tested on Radxa Dragon Q6A, based on the Qualcomm
> > QCS6490 SoC, with a Winbond W25Q256JWPIQ SPI NOR flash device.
> >
> > Note that this platform previously used the standard Qualcomm Linux
> > firmware, which allowed direct access to the QSPI controller without
> > needing this driver. However, we plan to migrate to a Windows-compatible
> > firmware which is more feature-complete but restricts direct access.
> > Device tree changes for this transition will be sent separately.
> >
> > If kernel boots with EL2, access to the SCM storage will be denied. This
> > needs more investigation.
> So you plan to enable this driver only w/ the Gunyah based configuration
> and disable for the KVM one through the devicetree overlay ? I just
> don't want to break the KVM boot flow on other platforms supporting
> qcs6490.

On systems booted with EL2/KVM, the SCM storage GET_INFO call currently
returns -EINVAL. If a platform does not support SPI-NOR or SCM storage,
__qcom_scm_is_call_available() will cause the initialization to bail out 
early.

There is no DT-based enable/disable mechanism, and this should not affect
KVM boot flow on other platforms.

Other QCS6490 LE platforms do not support SCM storage, as the LE firmware
does not support SPI-NOR boot. Radxa Dragon Q6A uses WP firmware and boots
from SPI-NOR.

The root cause of SCM storage being unavailable under EL2/KVM is still under
investigation.

[    0.770124] qcom_scm: convention: smc arm 64
[    0.775005] qcom_scm firmware:scm: qseecom: found qseecom with 
version 0x1402000
[    0.782990] qcom_scm firmware:scm: scm storage get info failed: -22
[    0.999095] qcom_qseecom qcom_qseecom: setting up client for 
qcom.tz.uefisecapp

Thanks for your reply.
Best regards,
Junhao Xie