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* [PATCH] pci: Disable I/O forwarding during autoconfiguration if unsupported
@ 2021-11-25 10:32 Pali Rohár
  2021-11-30  6:09 ` Stefan Roese
  2022-01-13  1:51 ` Tom Rini
  0 siblings, 2 replies; 5+ messages in thread
From: Pali Rohár @ 2021-11-25 10:32 UTC (permalink / raw)
  To: Stefan Roese, Simon Glass, Bin Meng; +Cc: u-boot

If U-Boot does not have any I/O resource for assignment then disable I/O
forwarding in PCI bridge autoconfiguration code. Default initial state of
PCI bridge IO registers is unspecified, therefore they can be in enabled if
U-Boot does not touch them.

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 drivers/pci/pci_auto.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/pci/pci_auto.c b/drivers/pci/pci_auto.c
index 7e6ee54be087..6e5ed194f247 100644
--- a/drivers/pci/pci_auto.c
+++ b/drivers/pci/pci_auto.c
@@ -265,6 +265,14 @@ void dm_pciauto_prescan_setup_bridge(struct udevice *dev, int sub_bus)
 				      (pci_io->bus_lower & 0xffff0000) >> 16);
 
 		cmdstat |= PCI_COMMAND_IO;
+	} else {
+		/* Disable I/O if unsupported */
+		dm_pci_write_config8(dev, PCI_IO_BASE, 0xf0 | io_32);
+		dm_pci_write_config8(dev, PCI_IO_LIMIT, 0x0 | io_32);
+		if (io_32 == PCI_IO_RANGE_TYPE_32) {
+			dm_pci_write_config16(dev, PCI_IO_BASE_UPPER16, 0x0);
+			dm_pci_write_config16(dev, PCI_IO_LIMIT_UPPER16, 0x0);
+		}
 	}
 
 	/* Enable memory and I/O accesses, enable bus master */
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2022-01-13  1:51 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-11-25 10:32 [PATCH] pci: Disable I/O forwarding during autoconfiguration if unsupported Pali Rohár
2021-11-30  6:09 ` Stefan Roese
2021-12-01 23:08   ` Pali Rohár
2021-12-02 15:36     ` Stefan Roese
2022-01-13  1:51 ` Tom Rini

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