interconnect: qcom: add MSM8x60 NoC driver

v2 addresses Jie's, Sashiko's and Dmitry's review of v1:

Binding (PATCH 1/2):
- Add the dt-binding schema (qcom,msm8660.yaml). v1 only shipped the ID header (Jie flagged the missing schema). The schema covers all four compatibles, per-fabric clock-name lists (bus/bus_a/ebi1/ebi1_a for AFAB; bus/bus_a/smi/smi_a for MMFAB; bus/bus_a for SFAB and DFAB) with descriptions for each clock (Dmitry), the required qcom,rpm phandle, and #interconnect-cells = <1>.

- Drop the SFPB/CFPB mention from the header commit message; those fabrics aren't modelled by the driver (Sashiko Low).

Driver (PATCH 2/2):
- Fix the bandwidth aggregation in msm8660_icc_set() (Sashiko High). v1 walked provider->nodes and re-summed n->avg_bw across all nodes, which double-counts: the framework already writes each path's bw to every node it traverses, so summing here gives e.g. master_bw + slave_bw for the same flow. v2 takes the max per-node rate across the provider (matches the qcom_icc_bus_aggregate() convention in icc-rpm.c).

- Switch to dynamic ICC node IDs via icc_node_create_dyn() and pointer-based linking via icc_link_nodes(), matching the icc-rpmh-style pattern (Dmitry). Drop the internal MSM8660_* enum entirely; struct msm8660_icc_node now carries a struct icc_node *node and a flexible link_nodes[] array of qnode pointers.

- Expand the DEFINE_QNODE macro (Dmitry); each of the 63 qnodes is now an explicit static struct definition, with forward declarations grouped at the top.

- Use dev_err_ptr_probe() in msm8660_get_rpm()'s deferred-probe paths (Dmitry).

- Limit the clock-bulk-get fallback to -ENOENT only (Dmitry); propagate every other error including -EPROBE_DEFER instead of "any non-DEFER continues without clock scaling".

- Kconfig: depend on MFD_QCOM_RPM=y so a built-in interconnect provider can't link against a modular RPM (Sashiko Low).

- struct msm8660_icc_node: const char *name (Sashiko Low).

On-device validation (HP TouchPad / APQ8060):
All four fabric providers probe cleanly:

qnoc-msm8660 soc:interconnect@0: RPM fabric ARB enabled
(4 masters, 4 slaves, 2 tiered) [AFAB]
qnoc-msm8660 soc:interconnect@1: RPM fabric ARB enabled
(17 masters, 9 slaves, 2 tiered) [SFAB]
qnoc-msm8660 soc:interconnect@2: RPM fabric ARB enabled
(14 masters, 4 slaves, 3 tiered) [MMFAB]
qnoc-msm8660 soc:interconnect@3: MSM8660 interconnect provider
registered [DFAB]
mmcc-msm8660: MMSS fabric: unhalted all master ports (0-13) msm_hsusb 12500000.usb: USB HS: Setting interconnect
bandwidth avg=61440 peak=61440 kBps

interconnect_summary shows the expected per-node aggregation (e.g. slv_ebi_ch0 sums MMC + MDP + DMA + USB consumer requests) and msm8660_icc_set() then derives a single fabric clock rate from the per-node max rather than the per-node sum (the v1 double-count is gone in v2).

The companion DTS patches that enable the providers for the HP TouchPad will be sent separately to the ARM/DTS tree.

Herman van Hazendonk (2):
dt-bindings: interconnect: qcom: add msm8660 NoC
interconnect: qcom: add MSM8x60 NoC driver

 .../bindings/interconnect/qcom,msm8660.yaml   |  157 ++
 drivers/interconnect/qcom/Kconfig             |   14 +
 drivers/interconnect/qcom/Makefile            |    2 +
 drivers/interconnect/qcom/msm8660.c           | 1619 +++++++++++++++++
 .../dt-bindings/interconnect/qcom,msm8660.h   |  156 ++
 5 files changed, 1948 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,msm8660.yaml
 create mode 100644 drivers/interconnect/qcom/msm8660.c
 create mode 100644 include/dt-bindings/interconnect/qcom,msm8660.h

base-commit: 944125b4c454b58d2fe6e35f1087a932b2050dff

2.43.0

Add a dt-binding schema and an interconnect master/slave ID header for the MSM8x60 family (MSM8260/MSM8660/APQ8060) Network-on-Chip. The chip exposes four NoC fabrics that the qnoc-msm8660 driver models:

AFAB - Applications fabric (Scorpion CPU + L2) SFAB - System fabric (DMA, SPS, security)
MMFAB - Multimedia fabric (MDP, GPU, camera, video, rotator) DFAB - Daytona fabric (SDC, ADM master/slave)

The schema covers all four compatible strings, per-fabric clock-name lists (bus / bus_a / ebi1 / ebi1_a for AFAB; bus / bus_a / smi / smi_a for MMFAB; bus / bus_a for SFAB and DFAB), the required qcom,rpm phandle through which the provider hands the arbitration buffer to RPM firmware, and #interconnect-cells = <1>.

The ID header lists per-fabric master / slave / gateway indices derived from the legacy vendor msm_bus_board_8660.c enums, normalised to the upstream interconnect-framework naming convention.

---
 .../bindings/interconnect/qcom,msm8660.yaml   | 157 ++++++++++++++++++
 .../dt-bindings/interconnect/qcom,msm8660.h   | 156 +++++++++++++++++
 2 files changed, 313 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,msm8660.yaml
 create mode 100644 include/dt-bindings/interconnect/qcom,msm8660.h

new file mode 100644
index 000000000000..f8b3a05d5ba1
@@ -0,0 +1,157 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interconnect/qcom,msm8660.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm MSM8x60 family Network-On-Chip interconnect
+
+maintainers:
+  - Herman van Hazendonk <[email protected]>
+
+description: |
+  The Qualcomm MSM8x60 family (MSM8260/MSM8660/APQ8060) NoC is split into
+  four fabrics, each modelled as a separate interconnect provider:
+
+    APPSS fabric    Scorpion CPU cluster, L2 cache, EBI (DDR) memory.
+    System fabric   DMA controllers, modem and LPASS cross-domain links,
+                    security peripherals.
+    Multimedia fab  Display (MDP), GPU, camera (VFE), video codec (VPE),
+                    JPEG, with the SMI scratchpad as the local slave.
+    Daytona fabric  SDC1..SDC5 controllers and ADM master/slave channels.
+
+  Each provider programs fabric arbitration (per-master priority tier and
+  per-slave bandwidth vote) through RPM firmware via the qcom,rpm parent
+  controller, in addition to scaling its bus clocks via clk_set_rate.
+
+properties:
+  compatible:
+    enum:
+      - qcom,msm8660-apps-fabric
+      - qcom,msm8660-system-fabric
+      - qcom,msm8660-mmss-fabric
+      - qcom,msm8660-daytona-fabric
+
+  clocks:
+    minItems: 2
+    maxItems: 4
+
+  clock-names:
+    minItems: 2
+    maxItems: 4
+
+  qcom,rpm:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to the qcom,rpm node.  The interconnect provider hands the
+      per-fabric arbitration buffer to RPM firmware through this resource,
+      so a production device tree must point at the system RPM.
+
+required:
+  - compatible
+  - clocks
+  - clock-names
+  - qcom,rpm
+  - '#interconnect-cells'
+
+allOf:
+  - $ref: qcom,rpm-common.yaml#
+  - if:
+      properties:
+        compatible:
+          const: qcom,msm8660-apps-fabric
+    then:
+      properties:
+        clocks:
+          items:
+            - description: APPSS fabric bus clock (active vote)
+            - description: APPSS fabric bus clock (active+sleep vote)
+            - description: EBI1 (DDR) channel clock (active vote)
+            - description: EBI1 (DDR) channel clock (active+sleep vote)
+        clock-names:
+          items:
+            - const: bus
+            - const: bus_a
+            - const: ebi1
+            - const: ebi1_a
+  - if:
+      properties:
+        compatible:
+          enum:
+            - qcom,msm8660-system-fabric
+            - qcom,msm8660-daytona-fabric
+    then:
+      properties:
+        clocks:
+          items:
+            - description: Fabric bus clock (active vote)
+            - description: Fabric bus clock (active+sleep vote)
+        clock-names:
+          items:
+            - const: bus
+            - const: bus_a
+  - if:
+      properties:
+        compatible:
+          const: qcom,msm8660-mmss-fabric
+    then:
+      properties:
+        clocks:
+          items:
+            - description: MMSS fabric bus clock (active vote)
+            - description: MMSS fabric bus clock (active+sleep vote)
+            - description: SMI scratchpad clock (active vote)
+            - description: SMI scratchpad clock (active+sleep vote)
+        clock-names:
+          items:
+            - const: bus
+            - const: bus_a
+            - const: smi
+            - const: smi_a
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/qcom,rpmcc.h>
+
+    interconnect-afab {
+        compatible = "qcom,msm8660-apps-fabric";
+        clocks = <&rpmcc RPM_APPS_FABRIC_CLK>,
+                 <&rpmcc RPM_APPS_FABRIC_A_CLK>,
+                 <&rpmcc RPM_EBI1_CLK>,
+                 <&rpmcc RPM_EBI1_A_CLK>;
+        clock-names = "bus", "bus_a", "ebi1", "ebi1_a";
+        qcom,rpm = <&rpm>;
+        #interconnect-cells = <1>;
+    };
+
+    interconnect-sfab {
+        compatible = "qcom,msm8660-system-fabric";
+        clocks = <&rpmcc RPM_SYS_FABRIC_CLK>,
+                 <&rpmcc RPM_SYS_FABRIC_A_CLK>;
+        clock-names = "bus", "bus_a";
+        qcom,rpm = <&rpm>;
+        #interconnect-cells = <1>;
+    };
+
+    interconnect-mmfab {
+        compatible = "qcom,msm8660-mmss-fabric";
+        clocks = <&rpmcc RPM_MM_FABRIC_CLK>,
+                 <&rpmcc RPM_MM_FABRIC_A_CLK>,
+                 <&rpmcc RPM_SMI_CLK>,
+                 <&rpmcc RPM_SMI_A_CLK>;
+        clock-names = "bus", "bus_a", "smi", "smi_a";
+        qcom,rpm = <&rpm>;
+        #interconnect-cells = <1>;
+    };
+
+    interconnect-dfab {
+        compatible = "qcom,msm8660-daytona-fabric";
+        clocks = <&rpmcc RPM_DAYTONA_FABRIC_CLK>,
+                 <&rpmcc RPM_DAYTONA_FABRIC_A_CLK>;
+        clock-names = "bus", "bus_a";
+        qcom,rpm = <&rpm>;
+        #interconnect-cells = <1>;
+    };
+...

2.43.0

Add a Qualcomm interconnect driver for the MSM8x60 family modelling the four NoC fabrics (APPSS, System, MMSS, Daytona) that connect masters and slaves on these Scorpion-class SoCs. The driver implements the interconnect-provider API to manage bandwidth between specific masters and slaves via the RPM arbitration tables.

Each fabric carries:
- A bus clock (managed via clk_bulk APIs) whose rate is the maximum per-node rate across the provider, following the icc-rpm.c convention. Summing all provider nodes would overcount, because the framework writes each path's bandwidth onto every node it traverses; taking the max picks the hottest single node, which is the correct fabric throughput requirement. A minimum floor of 384 MHz keeps the bus alive during concurrent USB and MDP activity (266 MHz was empirically insufficient).
- An RPM arbitration buffer (arb / bwsum) that the RPM firmware consumes via its shared-memory protocol; commits go via the qcom-rpm driver's set_resource API.

Nodes follow the icc-rpmh-style pattern: each qnode is a static struct with a flexible link_nodes[] array of qnode pointers, ICC IDs are assigned dynamically via icc_node_create_dyn(), and links are established with icc_link_nodes() at probe time. The dt-bindings header IDs remain per-fabric indices into the of_icc_xlate_onecell data array.

msm8660_get_rpm() pins the supplier with device_link_add() before reading drvdata so an unbind/rebind window cannot leave a stale qcom_rpm pointer; the EPROBE_DEFER paths route through dev_err_ptr_probe() for proper deferred-probe accounting. clk_bulk_prepare_enable() is paired with a devm_add_action_or_reset() cleanup so an EPROBE_DEFER from the RPM lookup does not leak the prepare/enable refcount across retries. The fabric rate cap uses min_t(u64,...) so a bandwidth request exceeding 4 GiB/s cannot wrap through u32 truncation into a near-zero clock rate that would halt the interconnect.

---
 drivers/interconnect/qcom/Kconfig             |   14 +
 drivers/interconnect/qcom/Makefile            |    2 +
 drivers/interconnect/qcom/msm8660.c           | 1619 +++++++++++++++++
 .../dt-bindings/interconnect/qcom,msm8660.h   |    6 +-
 4 files changed, 1638 insertions(+), 3 deletions(-)
 create mode 100644 drivers/interconnect/qcom/msm8660.c

index 786b4eda44b4..579a4e3ea33e 100644
@@ -80,6 +80,20 @@ config INTERCONNECT_QCOM_MSM8953
 	  This is a driver for the Qualcomm Network-on-Chip on msm8953-based
 	  platforms.
 
+config INTERCONNECT_QCOM_MSM8660
+	# bool, not tristate: this provider must be registered at
+	# core_initcall to be ready before icc_init (subsys_initcall) walks
+	# devicetree consumers; a loadable module cannot satisfy that
+	# ordering. Build-in only.
+	bool "Qualcomm MSM8x60 interconnect driver"
+	depends on INTERCONNECT_QCOM=y
+	depends on MFD_QCOM_RPM=y
+	help
+	  This is a driver for the Qualcomm fabric-based bus interconnect
+	  on MSM8x60 family (MSM8260/MSM8660/APQ8060) platforms (e.g., HP TouchPad).
+	  The driver manages APPSS, System, and MMSS fabrics and sends
+	  per-port bandwidth arbitration requests to RPM firmware.
+
 config INTERCONNECT_QCOM_MSM8974
 	tristate "Qualcomm MSM8974 interconnect driver"
 	depends on INTERCONNECT_QCOM

index cdf2c6c9fbf3..0c849c30a907 100644
@@ -13,6 +13,7 @@ qnoc-msm8916-objs			:= msm8916.o
 qnoc-msm8937-objs			:= msm8937.o
 qnoc-msm8939-objs			:= msm8939.o
 qnoc-msm8953-objs			:= msm8953.o
+qnoc-msm8660-objs			:= msm8660.o
 qnoc-msm8974-objs			:= msm8974.o
 qnoc-msm8976-objs			:= msm8976.o
 qnoc-msm8996-objs			:= msm8996.o

@@ -58,6 +59,7 @@ obj-$(CONFIG_INTERCONNECT_QCOM_MSM8916) += qnoc-msm8916.o
 obj-$(CONFIG_INTERCONNECT_QCOM_MSM8937) += qnoc-msm8937.o
 obj-$(CONFIG_INTERCONNECT_QCOM_MSM8939) += qnoc-msm8939.o
 obj-$(CONFIG_INTERCONNECT_QCOM_MSM8953) += qnoc-msm8953.o
+obj-$(CONFIG_INTERCONNECT_QCOM_MSM8660) += qnoc-msm8660.o
 obj-$(CONFIG_INTERCONNECT_QCOM_MSM8974) += qnoc-msm8974.o
 obj-$(CONFIG_INTERCONNECT_QCOM_MSM8976) += qnoc-msm8976.o
 obj-$(CONFIG_INTERCONNECT_QCOM_MSM8996) += qnoc-msm8996.o

index c9ce3f5a5276..bac9fc423da2 100644
@@ -4,7 +4,7 @@
  *
  * Copyright (c) 2026 Herman van Hazendonk <[email protected]>
  *
- * Based on webOS kernel msm_bus_board_8660.c
+ * Based on legacy vendor kernel msm_bus_board_8660.c
  * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
  */
 

@@ -79,11 +79,11 @@
  * Daytona Fabric (DFAB) - Peripheral bus
  *
  * DFAB connects slower peripherals (SDCC, ADM DMA) to the system fabric.
- * The webOS kernel managed DFAB bandwidth via voter clocks (dfab_sdc*_clk,
+ * The legacy vendor kernel managed DFAB bandwidth via voter clocks (dfab_sdc*_clk,
  * dfab_usb_hs_clk). In mainline, this is handled by the interconnect framework.
  *
  * USB HS is included as a DFAB voter for compatibility with the legacy clock
- * voting mechanism. The webOS kernel comment said: "if usb link is in sps
+ * voting mechanism. The legacy vendor kernel comment said: "if usb link is in sps
  * there is no need for usb pclk as daytona fabric clock will be used instead".
  * This keeps DFAB clock stable when USB is active.
  */

2.43.0