On Mon, Jun 22, 2026 at 09:20:50PM +0530, Mukesh Ojha wrote: > On Thu, Jun 18, 2026 at 03:53:22PM +0200, Konrad Dybcio wrote: > > On 4/30/26 9:12 PM, Mukesh Ojha wrote: > > > The firmware memory regions in qcom_adsp, qcom_pas and qcom_wcnss are > > > mapped using devm_ioremap_wc() / devm_ioremap_resource_wc(), which > > > return void __iomem *. However, the mem_region (and dtb_mem_region) > > > fields in the respective driver structs were declared as plain void *, > > > causing sparse to flag address space mismatches: > > > > > > qcom_q6v5_adsp.c:639:26: warning: incorrect type in assignment (different > > > address spaces) > > > qcom_q6v5_adsp.c:639:26: expected void *mem_region > > > qcom_q6v5_adsp.c:639:26: got void [noderef] __iomem * > > > qcom_q6v5_pas.c:141:45: warning: incorrect type in argument 2 (different > > > address spaces) > > > qcom_q6v5_pas.c:141:45: expected void const volatile [noderef] __iomem > > > *src > > > qcom_q6v5_pas.c:141:45: got void * > > > qcom_q6v5_pas.c:637:25: warning: incorrect type in assignment (different > > > address spaces) > > > qcom_q6v5_pas.c:637:25: expected void *mem_region > > > qcom_q6v5_pas.c:637:25: got void [noderef] __iomem * > > > qcom_q6v5_pas.c:654:29: warning: incorrect type in assignment (different > > > address spaces) > > > qcom_q6v5_pas.c:654:29: expected void *dtb_mem_region > > > qcom_q6v5_pas.c:654:29: got void [noderef] __iomem * > > > qcom_wcnss.c:540:27: warning: incorrect type in assignment (different > > > address spaces) > > > qcom_wcnss.c:540:27: expected void *mem_region > > > qcom_wcnss.c:540:27: got void [noderef] __iomem * > > > > > > Fix this by annotating the struct fields with __iomem to correctly > > > reflect the address space of the underlying mapping. > > > > > > These regions are subsequently passed to qcom_mdt_load(), > > > qcom_mdt_load_no_init() and qcom_mdt_pas_load(), all of which take > > > void * and use plain memcpy()/memset() internally to write firmware > > > segments into the region. This is intentional and safe: the mappings > > > are write-combining (WC), which on arm64 permits bulk CPU stores > > > without requiring the memcpy_toio()/memset_io() accessors. Changing > > > the MDT loader API to accept void __iomem * would be a more invasive > > > change and would affect callers. > > > > Zooming out a bit more, should we even be ioremapping these regions > > in the first place? Are they not just RAM/Normal Memory in arm parlance? > > Yes, ioremap may not be required. Don't know why it was kept in the > initial implementation, as for most Qualcomm SoCs this is going to be > normal RAM and not SRAM or something, while other implementations like > qcom_q6v5_mss still use memremap with MEMREMAP_WC. > > > > > Would switching to devm_memremap(, MEMREMAP_WC) (like we do in RMTFS > > today) be an even better solution here? > > This looks fine and I do not see any immediate impact; however, I would > like to hear from Bjorn on this, if there is any history..
Bjorn, I was looking for your view on this before I work on its revision. -- -Mukesh Ojha
