.../devicetree/bindings/net/qcom,bam-dmux.yaml | 8 +- drivers/net/wwan/Kconfig | 1 + drivers/net/wwan/qcom_bam_dmux.c | 134 +++++++++++++++++++-- 3 files changed, 132 insertions(+), 11 deletions(-)
On platforms where the modem DMAs into the BAM-DMUX RX data buffers and
the XPU (eXternal Protection Unit) enforces per-region access control,
each individually DMA-mapped RX buffer consumes an XPU resource group.
With only ~16 groups available on Shikra (mDSP, VMID 43 / NAV), the
per-buffer mappings exhaust the table and inbound transfers fault.
This series adds a qcom,shikra-bam-dmux compatible and have the driver
select QCOM_SCM_VMID_NAV internally via that compatible's match data.
When matched, the driver allocates all RX buffers as a single
contiguous coherent block and SCM-assigns it to HLOS plus the VMID
once at probe, consuming one XPU resource group instead of many.
Platforms that do not use the qcom,shikra-bam-dmux compatible are
unaffected: the existing per-buffer dma_map_single() path is
unchanged.
Signed-off-by: Vishnu Santhosh <vishnu.santhosh@oss.qualcomm.com>
---
Vishnu Santhosh (2):
dt-bindings: net: qcom,bam-dmux: Add qcom,shikra-bam-dmux compatible
net: wwan: qcom_bam_dmux: Alloc RX buffers as a single coherent block
.../devicetree/bindings/net/qcom,bam-dmux.yaml | 8 +-
drivers/net/wwan/Kconfig | 1 +
drivers/net/wwan/qcom_bam_dmux.c | 134 +++++++++++++++++++--
3 files changed, 132 insertions(+), 11 deletions(-)
---
base-commit: 3b029c035b34bbc693405ddf759f0e9b920c27f1
change-id: 20260714-qcom-bam-dmux-vmid-ext-d9289db310c1
Best regards,
--
Vishnu Santhosh <vishnu.santhosh@oss.qualcomm.com>
From: Vishnu Santhosh <vishnu.santhosh@oss.qualcomm.com> Sent: Tuesday, July 14, 2026 7:33 AM >On platforms where the modem DMAs into the BAM-DMUX RX data buffers and >the XPU (eXternal Protection Unit) enforces per-region access control, >each individually DMA-mapped RX buffer consumes an XPU resource group. >With only ~16 groups available on Shikra (mDSP, VMID 43 / NAV), the >per-buffer mappings exhaust the table and inbound transfers fault. > >This series adds a qcom,shikra-bam-dmux compatible and have the driver >select QCOM_SCM_VMID_NAV internally via that compatible's match data. >When matched, the driver allocates all RX buffers as a single >contiguous coherent block and SCM-assigns it to HLOS plus the VMID >once at probe, consuming one XPU resource group instead of many. > >Platforms that do not use the qcom,shikra-bam-dmux compatible are >unaffected: the existing per-buffer dma_map_single() path is >unchanged. > >Signed-off-by: Vishnu Santhosh <vishnu.santhosh@oss.qualcomm.com> >--- >Vishnu Santhosh (2): > dt-bindings: net: qcom,bam-dmux: Add qcom,shikra-bam-dmux compatible > net: wwan: qcom_bam_dmux: Alloc RX buffers as a single coherent block > > .../devicetree/bindings/net/qcom,bam-dmux.yaml | 8 +- > drivers/net/wwan/Kconfig | 1 + > drivers/net/wwan/qcom_bam_dmux.c | 134 +++++++++++++++++++-- > 3 files changed, 132 insertions(+), 11 deletions(-) >--- >base-commit: 3b029c035b34bbc693405ddf759f0e9b920c27f1 >change-id: 20260714-qcom-bam-dmux-vmid-ext-d9289db310c1 > >Best regards, >-- >Vishnu Santhosh <vishnu.santhosh@oss.qualcomm.com> Hi Vishnu you need to specify target tree, net-next for this series i believe please refer to[1] [1] https://docs.kernel.org/process/maintainer-netdev.html#indicating-target-tree
On 14-07-2026 01:23 pm, Jagielski, Jedrzej wrote: > From: Vishnu Santhosh <vishnu.santhosh@oss.qualcomm.com> > Sent: Tuesday, July 14, 2026 7:33 AM > >> On platforms where the modem DMAs into the BAM-DMUX RX data buffers and >> the XPU (eXternal Protection Unit) enforces per-region access control, >> each individually DMA-mapped RX buffer consumes an XPU resource group. >> With only ~16 groups available on Shikra (mDSP, VMID 43 / NAV), the >> per-buffer mappings exhaust the table and inbound transfers fault. >> >> This series adds a qcom,shikra-bam-dmux compatible and have the driver >> select QCOM_SCM_VMID_NAV internally via that compatible's match data. >> When matched, the driver allocates all RX buffers as a single >> contiguous coherent block and SCM-assigns it to HLOS plus the VMID >> once at probe, consuming one XPU resource group instead of many. >> >> Platforms that do not use the qcom,shikra-bam-dmux compatible are >> unaffected: the existing per-buffer dma_map_single() path is >> unchanged. >> >> Signed-off-by: Vishnu Santhosh <vishnu.santhosh@oss.qualcomm.com> >> --- >> Vishnu Santhosh (2): >> dt-bindings: net: qcom,bam-dmux: Add qcom,shikra-bam-dmux compatible >> net: wwan: qcom_bam_dmux: Alloc RX buffers as a single coherent block >> >> .../devicetree/bindings/net/qcom,bam-dmux.yaml | 8 +- >> drivers/net/wwan/Kconfig | 1 + >> drivers/net/wwan/qcom_bam_dmux.c | 134 +++++++++++++++++++-- >> 3 files changed, 132 insertions(+), 11 deletions(-) >> --- >> base-commit: 3b029c035b34bbc693405ddf759f0e9b920c27f1 >> change-id: 20260714-qcom-bam-dmux-vmid-ext-d9289db310c1 >> >> Best regards, >> -- >> Vishnu Santhosh <vishnu.santhosh@oss.qualcomm.com> > Hi Vishnu > you need to specify target tree, net-next for this series i believe > please refer to[1] > > [1] > https://docs.kernel.org/process/maintainer-netdev.html#indicating-target-tree > Thanks Jedrzej. I will address the comments and will send out the next revision specifying the target tree as net-next. Thanks, Vishnu
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