RE: [PATCH v4 net-next 7/8] net: mscc: ocelot: use index to set vcap policer

On Wed, Sep 22, 2021 at 13:18:37 +0000, Vladimir Oltean wrote:

quoted

Policer was previously automatically assigned from the highest index
to the lowest index from policer pool. But police action of tc flower
now uses index to set an police entry. This patch uses the police
index to set vcap policers, so that one policer can be shared by multiple

rules.

quoted

Signed-off-by: Xiaoliang Yang <redacted>
---
+#define VSC9959_VCAP_POLICER_BASE	63
+#define VSC9959_VCAP_POLICER_MAX	383

quoted

+#define VSC7514_VCAP_POLICER_BASE			128
+#define VSC7514_VCAP_POLICER_MAX			191

I think this deserves an explanation.

The VSC7514 driver uses the max number of policers as 383 (0x17f) ever since
commit b596229448dd ("net: mscc: ocelot: Add support for tcam"), aka the
very beginning.

Yet, the documentation at "3.10.1 Policer Allocation"
https://ww1.microchip.com/downloads/en/DeviceDoc/VMDS-10491.pdf
says very clearly that there are only 192 policers indeed.

What's going on?

In commit commit b596229448dd ("net: mscc: ocelot: Add support for tcam"), Horatiu Vultur define the max number of policers as 383:
+#define OCELOT_POLICER_DISCARD 0x17f
VCAP IS2 use this policer to set drop action. I did not change this and set the VCAP policers with 128-191 according to the VSC7514 document.

I don't know why 383 was used as the maximum value of policer in the original code. Can Microchip people check the code or the documentation for errors?

Also, FWIW, Seville has this policer allocation:

      0 ----+----------------------+
            |  Port Policers (11)  |
     11 ----+----------------------+
            |  VCAP Policers (21)  |
     32 ----+----------------------+
            |   QoS Policers (88)  |
    120 ----+----------------------+
            |  VCAP Policers (43)  |
    162 ----+----------------------+

I didn't find Seville's document, if this allocation is right, I will add it in Seville driver.

Thanks,
Xiaoliang