git: c733dc7a6f86 - main - ahc(4): Default to memory mapped IO

The branch main has been updated by imp:

URL: https://cgit.FreeBSD.org/src/commit/?id=c733dc7a6f866eeae0ac7762e6f1dee22e24c4d3

commit c733dc7a6f866eeae0ac7762e6f1dee22e24c4d3
Author:     HP van Braam <hp@tmm.cx>
AuthorDate: 2024-05-10 02:13:03 +0000
Commit:     Warner Losh <imp@FreeBSD.org>
CommitDate: 2024-05-10 02:15:08 +0000

    ahc(4): Default to memory mapped IO
    
    When this driver was written it made sense to make this default to off,
    but these days almost all BIOSses will do the right thing. Furthermore
    non-mmio communication only works on Intel architectures.
    
    So lets default to allowing mmio, but not change the semantics of the
    AHC_ALLOW_MEMIO flag to not break existing installs. Also document the
    already existing hint.ahc.<unit>.allow_memio.
    
    Signed-off-by: HP van Braam <hp@tmm.cx>
    Reviewed by: imp (small style tweak)
    Pull Request: https://github.com/freebsd/freebsd-src/pull/1219
---
 share/man/man4/ahc.4         | 13 +++++++++----
 sys/dev/aic7xxx/ahc_pci.c    | 12 ++++++------
 sys/powerpc/conf/GENERIC     |  1 -
 sys/powerpc/conf/GENERIC64   |  1 -
 sys/powerpc/conf/GENERIC64LE |  1 -
 5 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/share/man/man4/ahc.4 b/share/man/man4/ahc.4
index 7d5e092089bb..582b34fe2071 100644
--- a/share/man/man4/ahc.4
+++ b/share/man/man4/ahc.4
@@ -131,7 +131,7 @@ target on multiple SCSI IDs.
 .Pp
 To allow PCI adapters to use memory mapped I/O if enabled:
 .Pp
-.Cd options AHC_ALLOW_MEMIO
+.Cd options AHC_ALLOW_MEMIO=(0 -- disabled, 1 -- enabled)
 .Bd -ragged -offset indent
 Memory mapped I/O is more efficient than the alternative, programmed I/O.
 Most PCI BIOSes will map devices so that either technique for communicating
@@ -141,12 +141,13 @@ the chip for memory mapped I/O. The typical symptom of this problem is a
 system hang if memory mapped I/O is attempted.
 .Pp
 Most modern motherboards perform the initialization correctly and work fine
-with this option enabled.
+with this option enabled and it is the default. This option can also be
+dynamically configued through a device hint documented below.
 .Ed
 .Pp
 To statically configure one or more controllers to assume the target role:
 .Pp
-.Cd options AHC_TMODE_ENABLE <bitmask of units>
+.Cd options AHC_TMODE_ENABLE=<bitmask of units>
 .Bd -ragged -offset indent
 The value assigned to this option should be a bitmap of all units where target
 mode is desired. For example, a value of 0x25, would enable target mode on
@@ -163,7 +164,11 @@ The following options are switchable by setting values in
 They are:
 .Bl -tag -width indent
 .It Va hint.ahc. Ns Ar N Ns Va .tmode_enable
-A hint to define whether the SCSI target mode is enabled (0 -- disabled, 1 -- enabled).
+A hint to define whether the SCSI target mode is enabled, defaults to disabled
+(0 -- disabled, 1 -- enabled).
+.It Va hint.ahc. Ns Ar N Ns Va .allow_memio
+A hint to define whether memory mapped io is enabled or disabled for this
+adapter, defaults to enabled (0 -- disabled, 1 -- enabled).
 .El
 .Ed
 .Sh HARDWARE
diff --git a/sys/dev/aic7xxx/ahc_pci.c b/sys/dev/aic7xxx/ahc_pci.c
index 1f9cd33f9e00..8109a6714814 100644
--- a/sys/dev/aic7xxx/ahc_pci.c
+++ b/sys/dev/aic7xxx/ahc_pci.c
@@ -138,7 +138,7 @@ ahc_pci_map_registers(struct ahc_softc *ahc)
 	struct	resource *regs;
 	int	regs_type;
 	int	regs_id;
-	int	allow_memio;
+	int	allow_memio = 1;
 
 	regs = NULL;
 	regs_type = 0;
@@ -150,14 +150,14 @@ ahc_pci_map_registers(struct ahc_softc *ahc)
 			       "allow_memio", &allow_memio) != 0) {
 		if (bootverbose)
 			device_printf(ahc->dev_softc, "Defaulting to MEMIO ");
-#ifdef AHC_ALLOW_MEMIO
-		if (bootverbose)
-			printf("on\n");
-		allow_memio = 1;
-#else
+#if defined(AHC_ALLOW_MEMIO) && (AHC_ALLOW_MEMIO == 0)
 		if (bootverbose)
 			printf("off\n");
 		allow_memio = 0;
+#else
+		if (bootverbose)
+			printf("on\n");
+		allow_memio = 1;
 #endif
 	}
 
diff --git a/sys/powerpc/conf/GENERIC b/sys/powerpc/conf/GENERIC
index 6083b4d2baca..dedaa931f4ef 100644
--- a/sys/powerpc/conf/GENERIC
+++ b/sys/powerpc/conf/GENERIC
@@ -119,7 +119,6 @@ device		siis		# SiliconImage SiI3124/SiI3132/SiI3531 SATA
 
 # SCSI Controllers
 device		ahc		# AHA2940 and onboard AIC7xxx devices
-options 	AHC_ALLOW_MEMIO	# Attempt to use memory mapped I/O
 device		isp		# Qlogic family
 device		ispfw		# Firmware module for Qlogic host adapters
 device		mpt		# LSI-Logic MPT-Fusion
diff --git a/sys/powerpc/conf/GENERIC64 b/sys/powerpc/conf/GENERIC64
index 26b308a4e06e..2a5e3d377ab8 100644
--- a/sys/powerpc/conf/GENERIC64
+++ b/sys/powerpc/conf/GENERIC64
@@ -137,7 +137,6 @@ device		nvd		# expose NVMe namespaces as disks, depends on nvme
 # SCSI Controllers
 device		aacraid		# Adaptec by PMC RAID
 device		ahc		# AHA2940 and onboard AIC7xxx devices
-options 	AHC_ALLOW_MEMIO	# Attempt to use memory mapped I/O
 device		isp		# Qlogic family
 device		ispfw		# Firmware module for Qlogic host adapters
 device		mrsas		# LSI/Avago MegaRAID SAS/SATA, 6Gb/s and 12Gb/s
diff --git a/sys/powerpc/conf/GENERIC64LE b/sys/powerpc/conf/GENERIC64LE
index 84c27690211d..63e10df90200 100644
--- a/sys/powerpc/conf/GENERIC64LE
+++ b/sys/powerpc/conf/GENERIC64LE
@@ -133,7 +133,6 @@ device		nvd		# expose NVMe namespaces as disks, depends on nvme
 # SCSI Controllers
 device		aacraid		# Adaptec by PMC RAID
 device		ahc		# AHA2940 and onboard AIC7xxx devices
-options 	AHC_ALLOW_MEMIO	# Attempt to use memory mapped I/O
 device		isp		# Qlogic family
 device		ispfw		# Firmware module for Qlogic host adapters
 device		mrsas		# LSI/Avago MegaRAID SAS/SATA, 6Gb/s and 12Gb/s