[PATCH] Broadcom network card tips (0.2W)

[Török Edvin]

On 6/10/07, Török Edvin <edwintorok at gmail.com> wrote:
> Its strange why the card still generates link carrier signal, even if
> shut down (pci_disable_device), and in D3cold state. [and
> netif_carrier_down is called...]

Ok, I need to shut down the PHY interface on the card, like this:

bw32(bp, B44_MAC_CTRL, MAC_CTRL_PHY_PDOWN);

Also doing a partial chip reset turns the LEDs off too.

I get 0.3-0.5 W power savings (after ifconfig eth0 down, or rmmod b44)!

I updated yesterday's patch. Can somebody else with a Broadcom card
confirm the power savings?

If yes, intend to post this patch to the b44 maintainer.

--- linux-2.6/drivers/net/b44.c	2007-04-28 18:42:06.000000000 +0300
+++ b/drivers/net/b44.c	2007-06-11 12:16:58.000000000 +0300
@@ -1283,7 +1283,7 @@
 }

 /* bp->lock is held. */
-static void b44_chip_reset(struct b44 *bp)
+static void b44_chip_reset(struct b44 *bp, int powerdown)
 {
 	if (ssb_is_core_up(bp)) {
 		bw32(bp, B44_RCV_LAZY, 0);
@@ -1307,6 +1307,9 @@

 	b44_clear_stats(bp);

+	if(powerdown)
+		return;/* don't enable PHY if we are going to power down */
+	
 	/* Make PHY accessible. */
 	bw32(bp, B44_MDIO_CTRL, (MDIO_CTRL_PREAMBLE |
 			     (0x0d & MDIO_CTRL_MAXF_MASK)));
@@ -1332,7 +1335,14 @@
 static void b44_halt(struct b44 *bp)
 {
 	b44_disable_ints(bp);
-	b44_chip_reset(bp);
+	/* reset PHY */
+	b44_phy_reset(bp);
+	/* power down PHY */
+	printk(KERN_INFO "b44: powering down PHY\n");
+	bw32(bp, B44_MAC_CTRL, MAC_CTRL_PHY_PDOWN);
+	/* now reset the chip, but without enabling the MAC&PHY
+	 * part of it. This has to be done _after_ we shut down the PHY */
+	b44_chip_reset(bp, 1);
 }

 /* bp->lock is held. */
@@ -1376,7 +1386,7 @@
 {
 	u32 val;

-	b44_chip_reset(bp);
+	b44_chip_reset(bp, 0);
 	if (reset_kind == B44_FULL_RESET) {
 		b44_phy_reset(bp);
 		b44_setup_phy(bp);
@@ -1430,7 +1440,7 @@

 	err = request_irq(dev->irq, b44_interrupt, IRQF_SHARED, dev->name, dev);
 	if (unlikely(err < 0)) {
-		b44_chip_reset(bp);
+		b44_chip_reset(bp, 1);
 		b44_free_rings(bp);
 		b44_free_consistent(bp);
 		goto out;
@@ -2126,6 +2136,7 @@
 	if (b44_version_printed++ == 0)
 		printk(KERN_INFO "%s", version);

+	pci_set_power_state(pdev, PCI_D0);
 	err = pci_enable_device(pdev);
 	if (err) {
 		dev_err(&pdev->dev, "Cannot enable PCI device, "
@@ -2250,7 +2261,7 @@
 	/* Chip reset provides power to the b44 MAC & PCI cores, which
 	 * is necessary for MAC register access.
 	 */
-	b44_chip_reset(bp);
+	b44_chip_reset(bp, 0);

 	printk(KERN_INFO "%s: Broadcom 4400 10/100BaseT Ethernet ", dev->name);
 	for (i = 0; i < 6; i++)
@@ -2284,6 +2295,7 @@
 	free_netdev(dev);
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
+	pci_set_power_state(pdev, PCI_D3cold);
 	pci_set_drvdata(pdev, NULL);
 }