Ethernet switch framework

[Aleksandr Rybalko]

Hi embedders,  

Invite Marius to discussion if Marius don't have objections :)

On Thu, 10 Nov 2011 08:17:46 -0800
Adrian Chadd <adrian at freebsd.org> wrote:

> Hi!
> 
> This is great. Between you, gonzo@ and loos, I think we finally will
> have something to throw into -HEAD.
> 
> The miibus changes though - why did you need those? Can you run them
> by marius@ and see what he thinks?
> 
> 
> Adrian

Copy miibus diff here to easily scope it
Index: mii.c
===================================================================
--- mii.c	(revision 227410)
+++ mii.c	(working copy)
@@ -310,7 +310,13 @@
 	struct mii_attach_args ma, *args;
 	device_t *children, phy;
 	int bmsr, first, i, nchildren, offset, phymax, phymin, rv;
+	uint32_t phymask;
+	const char *value;
+	char *key;
 
+	phymask = 0xfffffffful;
+	key = "phyXX";
+
 	if (phyloc != MII_PHY_ANY && offloc != MII_OFFSET_ANY) {
 		printf("%s: phyloc and offloc specified\n", __func__);
 		return (EINVAL);
@@ -366,6 +372,9 @@
 
 	ma.mii_capmask = capmask;
 
+	resource_int_value(device_get_name(*miibus), device_get_unit
(*miibus),
+	    "phymask", &phymask);
+
 	phy = NULL;
 	offset = 0;
 	for (ma.mii_phyno = phymin; ma.mii_phyno <= phymax;
ma.mii_phyno++) { @@ -390,6 +399,26 @@
 		}
 
 		/*
+		 * If phymask don't have corresponding bit set, then
this PHY
+		 * id marked as muted, skip to next id.
+		 */
+		if (!(phymask & (1 << ma.mii_phyno)))
+			continue;
+
+		/*
+		 * Check if we have hinted driver. If so, attach it.
+		 */
+		value = NULL;
+		sprintf(key, "phy%d", ma.mii_phyno);
+		if (resource_string_value(device_get_name(*miibus),
+		    device_get_unit(*miibus), key, &value) == 0) {
+
+			ma.mii_id1 = 0;
+			ma.mii_id2 = 0;
+			goto attach_hinted;
+		}
+
+		/*
 		 * Check to see if there is a PHY at this address.
Note,
 		 * many braindead PHYs report 0/0 in their ID
registers,
 		 * so we test for media in the BMSR.
@@ -416,13 +445,14 @@
 	ma.mii_id1 = MIIBUS_READREG(dev, ma.mii_phyno,MII_PHYIDR1);
	ma.mii_id2 = MIIBUS_READREG(dev, ma.mii_phyno,MII_PHYIDR2); 
+attach_hinted:
 		ma.mii_offset = offset;
 		args = malloc(sizeof(struct mii_attach_args), M_DEVBUF,
 		    M_NOWAIT);
 		if (args == NULL)
 			goto skip;
 		bcopy((char *)&ma, (char *)args, sizeof(ma));
-		phy = device_add_child(*miibus, NULL, -1);
+		phy = device_add_child(*miibus, value, -1);
 		if (phy == NULL) {
 			free(args, M_DEVBUF);
 			goto skip;
===================================================================

So this diff have to parts:

1. cosmetic one - fetching and apply phymask from hints. Why I need it?
Because switches like Atheros AR8x16 map their registers into MDIO
space. So if we not filter it, we will have random set of PHYs on
miibusX. Mostly ukphy, but even ukphy making read to PHY registers and
this may corrupt switch driver data (registers which Read/Clear).

2. Second is easy and cheap way to pre-assign phy driver to
some PHY ID on MDIO. I need it because 
	a) some switches have no ID in MII_PHYIDR1 and MII_PHYIDR2
registers (BCM5325, AR8x16);
	b) in cases when AR8x16 on MDIO attached to many NIC's, after
first instance of driver initialize switch, second miibus instance
don't found any PHY's.
	c) D-Link DSR-500[1000] (Cavium Octeon CN5010 based), CN5010
have single MDIO bus for 3 Ethernet interfaces. First and second NICs
attached to MII0 and MII1 ports of BCM53115, but third attached to
real PHY :)

Last case I configuring with following hints:
hint.miibus.0.phymask="0x00000001"
hint.miibus.0.phy0="switch"
hint.miibus.2.phymask="0x00000020"
hint.miibus.2.phy5="plumbphy"
hint.miibus.3.phymask="0x00000100"

Maybe we have better way?

Will wait for any opinion.

WBW
-- 
Aleksandr Rybalko <ray at ddteam.net>