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Subject[patch 2.5.32] transparent PCI-to-PCI bridges
On Tue, Aug 27, 2002 at 06:29:23PM -0700, Linus Torvalds wrote:
> Why add a bitfield, and not just add single bitmembers?

Modified as you suggested. For now, "transparent" is the only field
added to the struct pci_dev. Adding other fields certainly looks
promising, but it will take some time...

Ivan.

--- 2.5.32/drivers/pci/quirks.c Tue Aug 27 23:26:32 2002
+++ linux/drivers/pci/quirks.c Fri Aug 30 18:32:32 2002
@@ -471,6 +471,11 @@ static void __init quirk_dunord ( struct
r -> end = 0xffffff;
}

+static void __init quirk_transparent_bridge(struct pci_dev *dev)
+{
+ dev->transparent = 1;
+}
+
/*
* The main table of quirks.
*/
@@ -525,6 +530,13 @@ static struct pci_fixup pci_fixups[] __i

{ PCI_FIXUP_FINAL, PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_VIPER_7410, quirk_amd_ioapic },
{ PCI_FIXUP_FINAL, PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_FE_GATE_700C, quirk_amd_ordering },
+ /*
+ * i82380FB mobile docking controller: its PCI-to-PCI bridge
+ * is subtractive decoding (transparent), and does indicate this
+ * in the ProgIf. Unfortunately, the ProgIf value is wrong - 0x80
+ * instead of 0x01.
+ */
+ { PCI_FIXUP_HEADER, PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82380FB, quirk_transparent_bridge },

{ 0 }
};
--- 2.5.32/drivers/pci/probe.c Tue Aug 27 23:26:36 2002
+++ linux/drivers/pci/probe.c Fri Aug 30 18:20:44 2002
@@ -128,6 +128,13 @@ void __devinit pci_read_bridge_bases(str
if (!dev) /* It's a host bus, nothing to read */
return;

+ if (dev->transparent) {
+ printk("Transparent bridge - %s\n", dev->name);
+ for(i = 0; i < 3; i++)
+ child->resource[i] = child->parent->resource[i];
+ return;
+ }
+
for(i=0; i<3; i++)
child->resource[i] = &dev->resource[PCI_BRIDGE_RESOURCES+i];

@@ -149,13 +156,6 @@ void __devinit pci_read_bridge_bases(str
res->flags = (io_base_lo & PCI_IO_RANGE_TYPE_MASK) | IORESOURCE_IO;
res->start = base;
res->end = limit + 0xfff;
- } else {
- /*
- * Ugh. We don't know enough about this bridge. Just assume
- * that it's entirely transparent.
- */
- printk(KERN_ERR "Unknown bridge resource %d: assuming transparent\n", 0);
- child->resource[0] = child->parent->resource[0];
}

res = child->resource[1];
@@ -167,10 +167,6 @@ void __devinit pci_read_bridge_bases(str
res->flags = (mem_base_lo & PCI_MEMORY_RANGE_TYPE_MASK) | IORESOURCE_MEM;
res->start = base;
res->end = limit + 0xfffff;
- } else {
- /* See comment above. Same thing */
- printk(KERN_ERR "Unknown bridge resource %d: assuming transparent\n", 1);
- child->resource[1] = child->parent->resource[1];
}

res = child->resource[2];
@@ -197,10 +193,6 @@ void __devinit pci_read_bridge_bases(str
res->flags = (mem_base_lo & PCI_MEMORY_RANGE_TYPE_MASK) | IORESOURCE_MEM | IORESOURCE_PREFETCH;
res->start = base;
res->end = limit + 0xfffff;
- } else {
- /* See comments above */
- printk(KERN_ERR "Unknown bridge resource %d: assuming transparent\n", 2);
- child->resource[2] = child->parent->resource[2];
}
}

@@ -388,6 +380,10 @@ int pci_setup_device(struct pci_dev * de
case PCI_HEADER_TYPE_BRIDGE: /* bridge header */
if (class != PCI_CLASS_BRIDGE_PCI)
goto bad;
+ /* The PCI-to-PCI bridge spec requires that subtractive
+ decoding (i.e. transparent) bridge must have programming
+ interface code of 0x01. */
+ dev->transparent = ((class & 0xff) == 1);
pci_read_bases(dev, 2, PCI_ROM_ADDRESS1);
break;

--- 2.5.32/arch/i386/pci/fixup.c Tue Aug 27 23:26:35 2002
+++ linux/arch/i386/pci/fixup.c Fri Aug 30 18:23:04 2002
@@ -166,6 +166,22 @@ static void __init pci_fixup_via_northbr
}
}

+/*
+ * For some weird reasons Intel decided that certain parts of their
+ * 815, 845 and some other chipsets must look like PCI-to-PCI bridges
+ * while they are obviously not. The 82801 family (AA, AB, BAM/CAM,
+ * BA/CA/DB and E) PCI bridges are actually HUB-to-PCI ones, according
+ * to Intel terminology. These devices do forward all addresses from
+ * system to PCI bus no matter what are their window settings, so they are
+ * "transparent" (or subtractive decoding) from programmers point of view.
+ */
+static void __init pci_fixup_transparent_bridge(struct pci_dev *dev)
+{
+ if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI &&
+ (dev->device & 0xff00) == 0x2400)
+ dev->transparent = 1;
+}
+
struct pci_fixup pcibios_fixups[] = {
{ PCI_FIXUP_HEADER, PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82451NX, pci_fixup_i450nx },
{ PCI_FIXUP_HEADER, PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82454GX, pci_fixup_i450gx },
@@ -183,5 +199,6 @@ struct pci_fixup pcibios_fixups[] = {
{ PCI_FIXUP_HEADER, PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8361, pci_fixup_via_northbridge_bug },
{ PCI_FIXUP_HEADER, PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8367_0, pci_fixup_via_northbridge_bug },
{ PCI_FIXUP_HEADER, PCI_VENDOR_ID_NCR, PCI_DEVICE_ID_NCR_53C810, pci_fixup_ncr53c810 },
+ { PCI_FIXUP_HEADER, PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_fixup_transparent_bridge },
{ 0 }
};
--- 2.5.32/include/linux/pci.h Tue Aug 27 23:26:42 2002
+++ linux/include/linux/pci.h Fri Aug 30 18:08:09 2002
@@ -385,6 +385,9 @@ struct pci_dev {
int ro; /* ISAPnP: read only */
unsigned short regs; /* ISAPnP: supported registers */

+ /* These fields are used by common fixups */
+ unsigned short transparent:1; /* Transparent PCI bridge */
+
int (*prepare)(struct pci_dev *dev); /* ISAPnP hooks */
int (*activate)(struct pci_dev *dev);
int (*deactivate)(struct pci_dev *dev);
-
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