Module Name: src
Committed By: uwe
Date: Thu Mar 17 23:05:01 UTC 2022
Modified Files:
src/sys/dev/pci: virtio_pci.c
Log Message:
virtio_pci_bus_space_write_8: don't use bus_space_write_8.
The standard says:
4.1.3.1 Driver Requirements: PCI Device Layout
For device configuration access, the driver MUST use ... 32-bit
wide and aligned accesses for ... 64-bit wide fields. For 64-bit
fields, the driver MAY access each of the high and low 32-bit parts
of the field independently.
NB: "MAY" in this text refers to "independently" (i.e. the order of
accesses) not "32-bit" (which is restricted by the earlier "MUST").
Note also that virtio_{read,write}_device_config_8 in virtio.c already
uses two 32-bit accesses.
To generate a diff of this commit:
cvs rdiff -u -r1.35 -r1.36 src/sys/dev/pci/virtio_pci.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/pci/virtio_pci.c
diff -u src/sys/dev/pci/virtio_pci.c:1.35 src/sys/dev/pci/virtio_pci.c:1.36
--- src/sys/dev/pci/virtio_pci.c:1.35 Thu Mar 17 22:53:13 2022
+++ src/sys/dev/pci/virtio_pci.c Thu Mar 17 23:05:01 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: virtio_pci.c,v 1.35 2022/03/17 22:53:13 uwe Exp $ */
+/* $NetBSD: virtio_pci.c,v 1.36 2022/03/17 23:05:01 uwe Exp $ */
/*
* Copyright (c) 2020 The NetBSD Foundation, Inc.
@@ -28,7 +28,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: virtio_pci.c,v 1.35 2022/03/17 22:53:13 uwe Exp $");
+__KERNEL_RCSID(0, "$NetBSD: virtio_pci.c,v 1.36 2022/03/17 23:05:01 uwe Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -694,21 +694,22 @@ virtio_pci_read_queue_size_10(struct vir
}
/*
- * By definition little endian only in v1.0 and 8 byters are allowed to be
- * written as two 4 byters
+ * By definition little endian only in v1.0. NB: "MAY" in the text
+ * below refers to "independently" (i.e. the order of accesses) not
+ * "32-bit" (which is restricted by the earlier "MUST").
*
- * This is not a general purpose function that can be used in any
- * driver. Virtio specifically allows the 8 byte bus transaction
- * to be split into two 4 byte transactions. Do not copy/use it
- * in other device drivers unless you know that the device accepts it.
+ * 4.1.3.1 Driver Requirements: PCI Device Layout
+ *
+ * For device configuration access, the driver MUST use ... 32-bit
+ * wide and aligned accesses for ... 64-bit wide fields. For 64-bit
+ * fields, the driver MAY access each of the high and low 32-bit parts
+ * of the field independently.
*/
static __inline void
virtio_pci_bus_space_write_8(bus_space_tag_t iot, bus_space_handle_t ioh,
bus_size_t offset, uint64_t value)
{
-#if defined(__HAVE_BUS_SPACE_8)
- bus_space_write_8(iot, ioh, offset, value);
-#elif _QUAD_HIGHWORD
+#if _QUAD_HIGHWORD
bus_space_write_4(iot, ioh, offset, BUS_ADDR_LO32(value));
bus_space_write_4(iot, ioh, offset + 4, BUS_ADDR_HI32(value));
#else
