Thread (2 messages) 2 messages, 2 authors, 2014-09-14

Re: [PATCH 4/5] dt-bindings: Add binding info for Xgene QMTM UIO driver

From: Mark Rutland <hidden>
Date: 2014-09-09 10:53:58
Also in: linux-arm-kernel, lkml

On Tue, Sep 09, 2014 at 10:56:58AM +0100, Ankit Jindal wrote:
quoted hunk
This patch adds device tree binding documentation for
Xgene QMTM UIO driver.

Signed-off-by: Ankit Jindal <redacted>
Signed-off-by: Tushar Jagad <redacted>
---
 .../devicetree/bindings/uio/uio_xgene_qmtm.txt     |   45 ++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/uio/uio_xgene_qmtm.txt
diff --git a/Documentation/devicetree/bindings/uio/uio_xgene_qmtm.txt b/Documentation/devicetree/bindings/uio/uio_xgene_qmtm.txt
new file mode 100644
index 0000000..b71831b
--- /dev/null
+++ b/Documentation/devicetree/bindings/uio/uio_xgene_qmtm.txt
@@ -0,0 +1,45 @@
+APM X-Gene QMTM UIO nodes
+
+QMTM UIO nodes are defined for user space access to on-chip QMTM device
+on APM X-Gene SOC using UIO framework.
+
Userspace vs kernel space has precisely _nothing_ to do with a HW
description.

This doesn't describe at all what the device is (e.g. what does QMTM
stand for, what is it used for?).

NAK.

Please ensure you Cc the devicetree list (devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org) in
future.
+Required properties:
+- compatible: Should be "apm,xgene-qmtm-uio"
This should definitely not have "uio" in the name.
+- reg: Address and length of the register set for the device. It contains the
+  information of registers in the same order as described by reg-names.
+- reg-names: Should contain the register set names
+  - "csr": QMTM control and status register address space.
+  - "fabric": QMTM memory mapped access to queue states.
These look ok, I guess.
+  - "qpool": Memory location for creating QMTM queues. This could be some
+    SRAM or reserved portion of RAM. It is expected that size and location
+    of qpool memory will be configurable via bootloader.
I don't follow why this should be described in a reg entry. This is not
a property of the device; this is a separate resource being assigned to
the device.

Why can the kernel not allocate this dynamically?

If you need a specific fixed pool, use the reserved-memory bindings.
+- clocks: Reference to the clock entry.
There is only one clock input to the IP block?
+- num_queues: Number of queues under this QMTM device.
s/_/-/, property names should use '-' rather than '_'.
+- devid: QMTM identification number for the system having multiple QMTM devices
What exactly is this used for? Why is the reg entry not sufficient?
+Optional properties:
+- status: Should be "ok" or "disabled" for enabled/disabled. Default is "ok".
This is so standard I don't see the point in documenting it.

Mark.
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