On 29.07.25 14:22, Nishanth Menon wrote: > On 10:36-20250728, huaqian.li@xxxxxxxxxxx wrote: >> From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> >> >> The TI Peripheral Virtualization Unit (PVU) permits to define a limited >> set of mappings for DMA requests on the system memory. Unlike with an >> IOMMU, there is no fallback to a memory-backed page table, only a fixed >> set of register-backed TLBs. Emulating an IOMMU behavior appears to be >> the more fragile the more fragmentation of pending requests occur. >> >> Therefore, this driver does not expose the PVU as an IOMMU. It rather >> introduces a simple, static interface to devices that are under >> restricted-dma-pool constraints. They can register their pools with the >> PVUs, enabling only those pools to work for DMA. As also MSI is issued >> as DMA, the PVU already register the related translator region of the >> AM654 as valid DMA target. >> >> This driver is the essential building block for limiting DMA from >> untrusted devices to clearly defined memory regions in the absence of a >> real IOMMU (SMMU). >> >> Co-developed-by: Diogo Ivo <diogo.ivo@xxxxxxxxxxx> >> Signed-off-by: Diogo Ivo <diogo.ivo@xxxxxxxxxxx> >> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> >> Signed-off-by: Li Hua Qian <huaqian.li@xxxxxxxxxxx> >> --- >> drivers/soc/ti/Kconfig | 4 + >> drivers/soc/ti/Makefile | 1 + >> drivers/soc/ti/ti-pvu.c | 500 ++++++++++++++++++++++++++++++++++++++++ >> include/linux/ti-pvu.h | 32 +++ >> 4 files changed, 537 insertions(+) >> create mode 100644 drivers/soc/ti/ti-pvu.c >> create mode 100644 include/linux/ti-pvu.h >> >> diff --git a/drivers/soc/ti/Kconfig b/drivers/soc/ti/Kconfig >> index 1a93001c9e36..af7173ad84de 100644 >> --- a/drivers/soc/ti/Kconfig >> +++ b/drivers/soc/ti/Kconfig >> @@ -82,6 +82,10 @@ config TI_PRUSS >> processors on various TI SoCs. It's safe to say N here if you're >> not interested in the PRU or if you are unsure. >> >> +config TI_PVU >> + bool "TI Peripheral Virtualization Unit driver" > > tristate please? Prefer to make this as a module. > > PCI_KEYSTONE is bool and needs this (if enabled). So this won't be a module in practice. Jan -- Siemens AG, Foundational Technologies Linux Expert Center
