Add a tunable hw.firewire.phydma_enable.

This is enabled by default.  It should be disabled for
those who are uneasy with peeking/poking from FireWire.

Please note sbp(4) and dcons(4) over FireWire need
this feature.

3 files changed, 19 insertions, 6 deletions

diff --git a/sys/dev/firewire/firewirereg.h b/sys/dev/firewire/firewirereg.h
index 5038868..d2d9d65 100644
--- a/sys/dev/firewire/firewirereg.h
+++ b/sys/dev/firewire/firewirereg.h
@@ -299,6 +299,7 @@ int fw_open_isodma(struct firewire_comm *, int);
 
 extern int firewire_debug;
 extern devclass_t firewire_devclass;
+extern int firewire_phydma_enable;
 
 #ifdef __DragonFly__
 #define		FWPRI		PCATCH
diff --git a/sys/dev/firewire/fwohci.c b/sys/dev/firewire/fwohci.c
index 06bdc01..cf8dfec 100644
--- a/sys/dev/firewire/fwohci.c
+++ b/sys/dev/firewire/fwohci.c
@@ -79,9 +79,13 @@
 #undef OHCI_DEBUG
 
 static int nocyclemaster = 0;
+int firewire_phydma_enable = 1;
 SYSCTL_DECL(_hw_firewire);
 SYSCTL_INT(_hw_firewire, OID_AUTO, nocyclemaster, CTLFLAG_RW, &nocyclemaster, 0,
         "Do not send cycle start packets");
+SYSCTL_INT(_hw_firewire, OID_AUTO, phydma_enable, CTLFLAG_RW,
+	&firewire_phydma_enable, 1, "Allow physical request DMA from firewire");
+TUNABLE_INT("hw.firewire.phydma_enable", &firewire_phydma_enable);
 
 static char dbcode[16][0x10]={"OUTM", "OUTL","INPM","INPL",
 		"STOR","LOAD","NOP ","STOP",};
@@ -1862,12 +1866,13 @@ fwohci_intr_core(struct fwohci_softc *sc, uint32_t stat, int count)
 
 		/* Allow async. request to us */
 		OWRITE(sc, OHCI_AREQHI, 1 << 31);
-		/* XXX insecure ?? */
-		/* allow from all nodes */
-		OWRITE(sc, OHCI_PREQHI, 0x7fffffff);
-		OWRITE(sc, OHCI_PREQLO, 0xffffffff);
-		/* 0 to 4GB regison */
-		OWRITE(sc, OHCI_PREQUPPER, 0x10000);
+		if (firewire_phydma_enable) {
+			/* allow from all nodes */
+			OWRITE(sc, OHCI_PREQHI, 0x7fffffff);
+			OWRITE(sc, OHCI_PREQLO, 0xffffffff);
+			/* 0 to 4GB region */
+			OWRITE(sc, OHCI_PREQUPPER, 0x10000);
+		}
 		/* Set ATRetries register */
 		OWRITE(sc, OHCI_ATRETRY, 1<<(13+16) | 0xfff);
 
diff --git a/sys/dev/firewire/sbp.c b/sys/dev/firewire/sbp.c
index 2d14bfd..6dc4de9 100644
--- a/sys/dev/firewire/sbp.c
+++ b/sys/dev/firewire/sbp.c
@@ -824,6 +824,10 @@ sbp_post_explore(void *arg)
 SBP_DEBUG(0)
 	printf("sbp_post_explore (sbp_cold=%d)\n", sbp_cold);
 END_DEBUG
+	/* We need physical access */
+	if (!firewire_phydma_enable)
+		return;
+
 	if (sbp_cold > 0)
 		sbp_cold --;
 
@@ -1946,6 +1950,9 @@ sbp_attach(device_t dev)
 			"SBP_MAXPHYS(%dKB).\n", DFLTPHYS / 1024,
 			SBP_MAXPHYS / 1024);
 
+	if (!firewire_phydma_enable)
+		device_printf(dev, "Warning, hw.firewire.phydma_enable must be 1 "
+			"for SBP over FireWire.\n");
 SBP_DEBUG(0)
 	printf("sbp_attach (cold=%d)\n", cold);
 END_DEBUG