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Subject[PATCH] PCI updates - 32-bit IO support
I have here a system which requires 32-bit IO addressing on its PCI
busses. Currently, Linux zeros the upper IO base/limit registers on
all PCI bridges, which prevents addresses being forwarded on this

The following patch the upper IO base/limit registers to be set
appropriately by the PCI layer.

This patch is being sent for review, and is targetted solely at 2.5.

diff -ur orig/drivers/pci/setup-bus.c linux/drivers/pci/setup-bus.c
--- orig/drivers/pci/setup-bus.c Sun Oct 14 20:53:14 2001
+++ linux/drivers/pci/setup-bus.c Tue Dec 18 23:20:13 2001
@@ -148,7 +181,10 @@
pci_write_config_dword(bridge, PCI_IO_BASE, l);

/* Clear upper 16 bits of I/O base/limit. */
- pci_write_config_dword(bridge, PCI_IO_BASE_UPPER16, 0);
+ pci_write_config_word(bridge, PCI_IO_BASE_UPPER16,
+ ranges.io_start >> 16);
+ pci_write_config_word(bridge, PCI_IO_LIMIT_UPPER16,
+ ranges.io_end >> 16);

/* Clear out the upper 32 bits of PREF base/limit. */
pci_write_config_dword(bridge, PCI_PREF_BASE_UPPER32, 0);

Russell King ( The developer of ARM Linux

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