Using writel without __iowmb() in MSM8953 USB driver leads to split transactions.
Qualcomm platforms use an offloaded Power Manager known as the RPM. Unlike simpler microcontrollers where drivers toggle registers directly, ARM64 drivers on MSM8953 must send "Sleep Set" and "Active Set" requests to the RPM to enable clocks and bus access. A low-quality driver will disable a clock locally without informing the RPM, causing system freezes. A high-quality driver utilizes the Common Clock Framework (CCF) with clk_bulk_prepare_enable and strictly adheres to the RPM handshake protocols defined in the soc/qcom kernel subsystems.
Cross compiling for aarch64. In order to compile for a different target architecture (aarch64) on a host machine (for example x86) msm8953-mainline - GitHub
