[RFC PATCH 0/4] Add logic to consolidate TRBs for Synopsys xHC

[RFC PATCH 0/4] Add logic to consolidate TRBs for Synopsys xHC

[Tejas Joglekar]

The Synopsys xHC has an internal TRB cache of size TRB_CACHE_SIZE for
each endpoint. The default value for TRB_CACHE_SIZE is 16 for SS and 8
for HS. The controller loads and updates the TRB cache from the
transfer ring in system memory whenever the driver issues a start
transfer or update transfer command.

For chained TRBs, the Synopsys xHC requires that the total amount of
bytes for all TRBs loaded in the TRB cache be greater than or equal to
1 MPS. Or the chain ends within the TRB cache (with a last TRB).

If this requirement is not met, the controller will not be able to
send or receive a packet and it will hang causing a driver timeout and
error.

This patch set adds logic to the XHCI driver to detect and prevent this
from happening along with the quirk to enable this logic for Synopsys
HAPS platform.


Tejas Joglekar (4):
  usb: xhci: Synopsys xHC consolidate TRBs
  usb: dwc3: Add device property consolidate-trbs
  usb: xhci: Set quirk for XHCI_CONSOLIDATE_TRBS
  dt-bindings: usb: Add snps,consolidate-trbs & consolidate-trbs

 Documentation/devicetree/bindings/usb/dwc3.txt     |   6 +
 Documentation/devicetree/bindings/usb/usb-xhci.txt |   1 +
 drivers/usb/dwc3/core.c                            |   2 +
 drivers/usb/dwc3/core.h                            |   2 +
 drivers/usb/dwc3/dwc3-haps.c                       |   1 +
 drivers/usb/dwc3/host.c                            |   3 +
 drivers/usb/host/xhci-pci.c                        |   3 +
 drivers/usb/host/xhci-plat.c                       |   3 +
 drivers/usb/host/xhci-ring.c                       | 278 ++++++++++++++++++++-
 drivers/usb/host/xhci.c                            |   3 +
 drivers/usb/host/xhci.h                            |  23 ++
 11 files changed, 317 insertions(+), 8 deletions(-)

-- 
2.11.0

[RFC PATCH 4/4] dt-bindings: usb: Add snps,consolidate-trbs & consolidate-trbs

[Tejas Joglekar]

This commit adds the documentation for consolidate-trbs, and
snps,consolidate-trbs property. These when set enables the quirk for
XHCI driver for consolidation of TRB's when small buffer sizes are
scattered over the TRB cache not making up to MPS or total transfer size
with Synopsys xHC.

Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
---
 Documentation/devicetree/bindings/usb/dwc3.txt     | 6 ++++++
 Documentation/devicetree/bindings/usb/usb-xhci.txt | 1 +
 2 files changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
index 66780a47ad85..9851da41a442 100644
--- a/Documentation/devicetree/bindings/usb/dwc3.txt
+++ b/Documentation/devicetree/bindings/usb/dwc3.txt
@@ -101,6 +101,12 @@ Optional properties:
 			this and tx-thr-num-pkt-prd to a valid, non-zero value
 			1-16 (DWC_usb31 programming guide section 1.2.3) to
 			enable periodic ESS TX threshold.
+ - snps,consolidate-trbs: enable TRBs consolidation - host mode only. Set this
+			to valid then for Synopsys xHC the TRBs would be
+			consolidated to at least MPS in order to prevent the
+			controller getting hang due to small buffer sizes which
+			does not make up to MPS size or total transfer size
+			across TRB cache.
 
  - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
  - snps,incr-burst-type-adjustment: Value for INCR burst type of GSBUSCFG0
diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
index 3f378951d624..be8d5e6a6333 100644
--- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
@@ -43,6 +43,7 @@ Optional properties:
   - quirk-broken-port-ped: set if the controller has broken port disable mechanism
   - imod-interval-ns: default interrupt moderation interval is 5000ns
   - phys : see usb-hcd.yaml in the current directory
+  - consolidate-trbs: indicate if you need to consolidate trbs
 
 additionally the properties from usb-hcd.yaml (in the current directory) are
 supported.
-- 
2.11.0

Re: [RFC PATCH 4/4] dt-bindings: usb: Add snps,consolidate-trbs & consolidate-trbs

[Rob Herring]

On Fri, Dec 20, 2019 at 07:10:24PM +0530, Tejas Joglekar wrote:
> This commit adds the documentation for consolidate-trbs, and
> snps,consolidate-trbs property. These when set enables the quirk for
> XHCI driver for consolidation of TRB's when small buffer sizes are
> scattered over the TRB cache not making up to MPS or total transfer size
> with Synopsys xHC.
> 
> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
> ---
>  Documentation/devicetree/bindings/usb/dwc3.txt     | 6 ++++++
>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 1 +
>  2 files changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
> index 66780a47ad85..9851da41a442 100644
> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
> @@ -101,6 +101,12 @@ Optional properties:
>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>  			enable periodic ESS TX threshold.
> + - snps,consolidate-trbs: enable TRBs consolidation - host mode only. Set this
> +			to valid then for Synopsys xHC the TRBs would be
> +			consolidated to at least MPS in order to prevent the
> +			controller getting hang due to small buffer sizes which
> +			does not make up to MPS size or total transfer size
> +			across TRB cache.

Why not just always enable this?

Otherwise, this should be implied by the compatible string.

>  
>   - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
>   - snps,incr-burst-type-adjustment: Value for INCR burst type of GSBUSCFG0
> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> index 3f378951d624..be8d5e6a6333 100644
> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> @@ -43,6 +43,7 @@ Optional properties:
>    - quirk-broken-port-ped: set if the controller has broken port disable mechanism
>    - imod-interval-ns: default interrupt moderation interval is 5000ns
>    - phys : see usb-hcd.yaml in the current directory
> +  - consolidate-trbs: indicate if you need to consolidate trbs
>  
>  additionally the properties from usb-hcd.yaml (in the current directory) are
>  supported.
> -- 
> 2.11.0
>