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Subject[PATCH] PCI legacy resource fix
Since commit 368c73d4f689dae0807d0a2aa74c61fd2b9b075f the kernel will try
to update the non-writeable BAR registers 0..3 of PIIX4 IDE adapters if
pci_assign_unassigned_resources() is used to do full resource assignment
of the bus. This fails because in the PIIX4 these BAR registers have
implicitly assumed values and read back as zero; it used to work because
the kernel used to just write zero to that register the read back value
did match what was written.

The fix is a new resource flag IORESOURCE_PCI_FIXED used to mark a
resource as non-movable. This will also be useful to keep other import
system resources from being moved around - for example system consoles
on PCI busses.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 0eeac60..045ad71 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -649,6 +649,9 @@ static void pci_read_irq(struct pci_dev
* Returns 0 on success and -1 if unknown type of device (not normal, bridge
* or CardBus).
*/
+
+#define LEGACY_IO_RESOURCE (IORESOURCE_IO | IORESOURCE_PCI_FIXED)
+
static int pci_setup_device(struct pci_dev * dev)
{
u32 class;
@@ -692,18 +695,18 @@ static int pci_setup_device(struct pci_d
if ((progif & 1) == 0) {
dev->resource[0].start = 0x1F0;
dev->resource[0].end = 0x1F7;
- dev->resource[0].flags = IORESOURCE_IO;
+ dev->resource[0].flags = LEGACY_IO_RESOURCE;
dev->resource[1].start = 0x3F6;
dev->resource[1].end = 0x3F6;
- dev->resource[1].flags = IORESOURCE_IO;
+ dev->resource[1].flags = LEGACY_IO_RESOURCE;
}
if ((progif & 4) == 0) {
dev->resource[2].start = 0x170;
dev->resource[2].end = 0x177;
- dev->resource[2].flags = IORESOURCE_IO;
+ dev->resource[2].flags = LEGACY_IO_RESOURCE;
dev->resource[3].start = 0x376;
dev->resource[3].end = 0x376;
- dev->resource[3].flags = IORESOURCE_IO;
+ dev->resource[3].flags = LEGACY_IO_RESOURCE;
}
}
break;
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index ab78e4b..064b3f3 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -38,6 +38,13 @@ pci_update_resource(struct pci_dev *dev,
if (!res->flags)
return;

+ /* Ignore non-moveable resources. This might be legacy resources for
+ which no functional BAR register exists or another important
+ system resource we should better not move around in system address
+ space. */
+ if (res->flags & IORESOURCE_PCI_FIXED)
+ return;
+
pcibios_resource_to_bus(dev, &region, res);

pr_debug(" got res [%llx:%llx] bus [%lx:%lx] flags %lx for "
@@ -212,6 +219,10 @@ pdev_sort_resources(struct pci_dev *dev,
resource_size_t r_align;

r = &dev->resource[i];
+
+ if (r->flags & IORESOURCE_PCI_FIXED)
+ continue;
+
r_align = r->end - r->start;

if (!(r->flags) || r->parent)
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index cf8696d..15228d7 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -91,6 +91,9 @@ #define IORESOURCE_ROM_SHADOW (1<<1) /*
#define IORESOURCE_ROM_COPY (1<<2) /* ROM is alloc'd copy, resource field overlaid */
#define IORESOURCE_ROM_BIOS_COPY (1<<3) /* ROM is BIOS copy, resource field overlaid */

+/* PCI control bits. Shares IORESOURCE_BITS with above PCI ROM. */
+#define IORESOURCE_PCI_FIXED (1<<4) /* Do not move resource */
+
/* PC/ISA/whatever - the normal PC address spaces: IO and memory */
extern struct resource ioport_resource;
extern struct resource iomem_resource;
-
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