Thread (38 messages) 38 messages, 5 authors, 2024-07-13

Re: [PATCH v2 01/12] dt-bindings: PCI: Add Broadcom STB 7712 SOC, update maintainer

From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2024-07-13 09:52:39
Also in: linux-devicetree, linux-pci, lkml

On 12/07/2024 21:54, Jim Quinlan wrote:
On Thu, Jul 4, 2024 at 2:40 AM Krzysztof Kozlowski [off-list ref] wrote:
quoted
On 03/07/2024 20:02, Jim Quinlan wrote:
quoted
- Update maintainer; Nicolas hasn't been active and it
  makes more sense to have a Broadcom maintainer
- Add a driver compatible string for the new STB SOC 7712
You meant device? Bindings are for hardware.
Hello Krzysztof,

I should have replied to this before sending out V3.  Since your form
letter says I did not address previous comments, I will address them
here and now (your v2 review of the bindings commit).
quoted
quoted
- Add two new resets for the 7712: "bridge", for the
  the bridge between the PCIe core and the memory bus;
  "swinit", the PCIe core reset.
- Order the compatible strings alphabetically
- Restructure the reset controllers so that the definitions
  appear first before any rules that govern them.
Please split cleanups from new device support.
Okay.
quoted
quoted
Signed-off-by: Jim Quinlan <redacted>
---
 .../bindings/pci/brcm,stb-pcie.yaml           | 44 +++++++++++++++----
 1 file changed, 36 insertions(+), 8 deletions(-)
diff --git a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml
index 11f8ea33240c..a070f35d28d7 100644
--- a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml
+++ b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml
@@ -7,7 +7,7 @@ $schema: http://devicetree.org/meta-schemas/core.yaml#
 title: Brcmstb PCIe Host Controller

 maintainers:
-  - Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
+  - Jim Quinlan <james.quinlan@broadcom.com>

 properties:
   compatible:
@@ -16,11 +16,12 @@ properties:
           - brcm,bcm2711-pcie # The Raspberry Pi 4
           - brcm,bcm4908-pcie
           - brcm,bcm7211-pcie # Broadcom STB version of RPi4
-          - brcm,bcm7278-pcie # Broadcom 7278 Arm
           - brcm,bcm7216-pcie # Broadcom 7216 Arm
-          - brcm,bcm7445-pcie # Broadcom 7445 Arm
+          - brcm,bcm7278-pcie # Broadcom 7278 Arm
           - brcm,bcm7425-pcie # Broadcom 7425 MIPs
           - brcm,bcm7435-pcie # Broadcom 7435 MIPs
+          - brcm,bcm7445-pcie # Broadcom 7445 Arm
+          - brcm,bcm7712-pcie # STB sibling SOC of Raspberry Pi 5

   reg:
     maxItems: 1
@@ -95,6 +96,20 @@ properties:
       minItems: 1
       maxItems: 3

+  resets:
+    items:
+      - description: reset for phy calibration
+      - description: reset for PCIe/CPU bus bridge
+      - description: reset for soft PCIe core reset
+      - description: reset for PERST# PCIe signal
This won't work and I doubt you tested your code. You miss minItems.
quoted
+
+  reset-names:
+    items:
+      - const: rescal
+      - const: bridge
+      - const: swinit
+      - const: perst
This does not match what you have in conditional, so just keep min and
max Items here.
I do not understand.  There are four possible resets, but any one chip
uses only 0, 1, or 3 of them:

    CHIP            NUM_RESETS    NAMES
    ====            ==========    =====
    4908            1             perst
    7216            1             rescal
    7712            3             rescal, bridge, swinit
    Other_Chips     0             -

Although I list four "reset-names", I have, in the rule for 7712,
maxItems=3 because it only uses rescal, bridge, and swinit.  So I
don't know what you mean when you say "this does not match what you
have in your conditional".  AFAICT, they are not supposed to match.
One place says they have order A+B+C, other place says they have order
C+B+A or whatever other combination. Look at first element: A ! = C. So
they do not match.

quoted
quoted
+
 required:
   - compatible
   - reg
@@ -118,13 +133,10 @@ allOf:
     then:
       properties:
         resets:
-          items:
-            - description: reset controller handling the PERST# signal
-
+          minItems: 1
maxItems instead. Why three resets should be valid?
For the "4908" conditional, minItems==maxItems==1.  I do not
understand your question "Why three resets should be valid" -- can you
please elaborate?
Where do you have maxItems? I see only minItems.
quoted
quoted
         reset-names:
           items:
             - const: perst
-
       required:
         - resets
         - reset-names
@@ -136,12 +148,28 @@ allOf:
     then:
       properties:
         resets:
+          minItems: 1
+        reset-names:
           items:
-            - description: phandle pointing to the RESCAL reset controller
+            - const: rescal
+      required:
+        - resets
+        - reset-names
Why?
I do not know what you are questioning.  The 7216 device uses one
reset: the "rescal".  Again, maxItems==minItems==1.  Please see the
summary note below.
You are breaking the ABI, so I am questioning. I don't see ABI break
explained in the commit msg.
quoted
quoted
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: brcm,bcm7712-pcie
+    then:
+      properties:
+        resets:
+          minItems: 3
Again, you do not have 4 items here.
I do not want to have 4 items here; I want to have 3 for "rescal",
"bridge," and "swinit".  In this case, maxItems==minItems==3.
Your schema does not define that.
Now , for V1 you requested that I define all resets at the top; I've
done that and there are 4 of them.  But no chip uses all 4; each
individual chip only uses 0, 1, or 3 resets.
I assumed they follow same order. If you have different order, the top
defines only widest constraints.
So there is no way that each chip's conditional rule can define
minItems and maxItems to match the description list of 4 resets,
unless you want me to undo your V1 request of describing the resets at
the top level instead of describing them in the rules.

Best regards,
Krzysztof

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