From 2c0dd4bbe4e239ac9588a0c284164cd7324f4573 Mon Sep 17 00:00:00 2001
From: Adrian Chadd <adrian@FreeBSD.org>
Date: Tue, 18 Oct 2011 03:32:18 +0000
Subject: [PATCH] Add in a currently-disabled WAR for PCI NICs.

Some earlier series (~AR5212?) play badly with BIOSes.

In these instances, they may require a forced reset (by transitioning
the NIC through D0 -> D3 -> D0) before they probe/attach correctly.

This is currently disabled because:

* I haven't figured out the "right" code to ensure this only happens
  for PCI NICs (not PCIe or Cardbus);
* I haven't at all done wide scale testing for this, and I'm not yet
  ready for said wide-scale testing.

I'm documenting this primarily so users with misbehaving NICs have
something to tinker with.

Obtained from:	Atheros
---
 sys/dev/ath/if_ath_pci.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/sys/dev/ath/if_ath_pci.c b/sys/dev/ath/if_ath_pci.c
index 531c79adb744..4824773dc8fd 100644
--- a/sys/dev/ath/if_ath_pci.c
+++ b/sys/dev/ath/if_ath_pci.c
@@ -73,10 +73,27 @@ struct ath_pci_softc {
 
 #define	BS_BAR	0x10
 #define	PCIR_RETRY_TIMEOUT	0x41
+#define	PCIR_CFG_PMCSR		0x48
 
 static void
 ath_pci_setup(device_t dev)
 {
+	/* Override the system latency timer */
+	pci_write_config(dev, PCIR_LATTIMER, 0x80, 1);
+
+	/* If a PCI NIC, force wakeup */
+#ifdef	ATH_PCI_WAKEUP_WAR
+	/* XXX TODO: don't do this for non-PCI (ie, PCIe, Cardbus!) */
+	if (1) {
+		uint16_t pmcsr;
+		pmcsr = pci_read_config(dev, PCIR_CFG_PMCSR, 2);
+		pmcsr |= 3;
+		pci_write_config(dev, PCIR_CFG_PMCSR, pmcsr, 2);
+		pmcsr &= ~3;
+		pci_write_config(dev, PCIR_CFG_PMCSR, pmcsr, 2);
+	}
+#endif
+
 	/*
 	 * Disable retry timeout to keep PCI Tx retries from
 	 * interfering with C3 CPU state.