* [PATCH] PCI: xgene: Fix CRS SV comment
@ 2021-01-26 21:35 ` Bjorn Helgaas
0 siblings, 0 replies; 4+ messages in thread
From: Bjorn Helgaas @ 2021-01-26 21:35 UTC (permalink / raw)
To: Toan Le, Lorenzo Pieralisi, Rob Herring
Cc: linux-arm-kernel, linux-pci, Bjorn Helgaas
From: Bjorn Helgaas <bhelgaas@google.com>
Configuration Request Retry Status ("CRS") must be supported by all PCIe
devices. CRS Software Visibility is an optional feature that enables a
Root Port to make CRS visible to software by returning a special data value
to complete a config read.
Clarify a comment to say that it is "CRS SV", not "CRS", that can be
enabled.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/controller/pci-xgene.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/controller/pci-xgene.c b/drivers/pci/controller/pci-xgene.c
index 85e7c98265e8..2afdc865253e 100644
--- a/drivers/pci/controller/pci-xgene.c
+++ b/drivers/pci/controller/pci-xgene.c
@@ -173,12 +173,13 @@ static int xgene_pcie_config_read32(struct pci_bus *bus, unsigned int devfn,
/*
* The v1 controller has a bug in its Configuration Request
- * Retry Status (CRS) logic: when CRS is enabled and we read the
- * Vendor and Device ID of a non-existent device, the controller
- * fabricates return data of 0xFFFF0001 ("device exists but is not
- * ready") instead of 0xFFFFFFFF ("device does not exist"). This
- * causes the PCI core to retry the read until it times out.
- * Avoid this by not claiming to support CRS.
+ * Retry Status (CRS) logic: when CRS Software Visibility is
+ * enabled and we read the Vendor and Device ID of a non-existent
+ * device, the controller fabricates return data of 0xFFFF0001
+ * ("device exists but is not ready") instead of 0xFFFFFFFF
+ * ("device does not exist"). This causes the PCI core to retry
+ * the read until it times out. Avoid this by not claiming to
+ * support CRS SV.
*/
if (pci_is_root_bus(bus) && (port->version == XGENE_PCIE_IP_VER_1) &&
((where & ~0x3) == XGENE_V1_PCI_EXP_CAP + PCI_EXP_RTCTL))
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] PCI: xgene: Fix CRS SV comment
@ 2021-01-26 21:35 ` Bjorn Helgaas
0 siblings, 0 replies; 4+ messages in thread
From: Bjorn Helgaas @ 2021-01-26 21:35 UTC (permalink / raw)
To: Toan Le, Lorenzo Pieralisi, Rob Herring
Cc: Bjorn Helgaas, linux-pci, linux-arm-kernel
From: Bjorn Helgaas <bhelgaas@google.com>
Configuration Request Retry Status ("CRS") must be supported by all PCIe
devices. CRS Software Visibility is an optional feature that enables a
Root Port to make CRS visible to software by returning a special data value
to complete a config read.
Clarify a comment to say that it is "CRS SV", not "CRS", that can be
enabled.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/controller/pci-xgene.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/controller/pci-xgene.c b/drivers/pci/controller/pci-xgene.c
index 85e7c98265e8..2afdc865253e 100644
--- a/drivers/pci/controller/pci-xgene.c
+++ b/drivers/pci/controller/pci-xgene.c
@@ -173,12 +173,13 @@ static int xgene_pcie_config_read32(struct pci_bus *bus, unsigned int devfn,
/*
* The v1 controller has a bug in its Configuration Request
- * Retry Status (CRS) logic: when CRS is enabled and we read the
- * Vendor and Device ID of a non-existent device, the controller
- * fabricates return data of 0xFFFF0001 ("device exists but is not
- * ready") instead of 0xFFFFFFFF ("device does not exist"). This
- * causes the PCI core to retry the read until it times out.
- * Avoid this by not claiming to support CRS.
+ * Retry Status (CRS) logic: when CRS Software Visibility is
+ * enabled and we read the Vendor and Device ID of a non-existent
+ * device, the controller fabricates return data of 0xFFFF0001
+ * ("device exists but is not ready") instead of 0xFFFFFFFF
+ * ("device does not exist"). This causes the PCI core to retry
+ * the read until it times out. Avoid this by not claiming to
+ * support CRS SV.
*/
if (pci_is_root_bus(bus) && (port->version == XGENE_PCIE_IP_VER_1) &&
((where & ~0x3) == XGENE_V1_PCI_EXP_CAP + PCI_EXP_RTCTL))
--
2.25.1
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] PCI: xgene: Fix CRS SV comment
2021-01-26 21:35 ` Bjorn Helgaas
@ 2021-01-28 10:47 ` Lorenzo Pieralisi
-1 siblings, 0 replies; 4+ messages in thread
From: Lorenzo Pieralisi @ 2021-01-28 10:47 UTC (permalink / raw)
To: Bjorn Helgaas, Rob Herring, Toan Le
Cc: Lorenzo Pieralisi, linux-arm-kernel, Bjorn Helgaas, linux-pci
On Tue, 26 Jan 2021 15:35:03 -0600, Bjorn Helgaas wrote:
> Configuration Request Retry Status ("CRS") must be supported by all PCIe
> devices. CRS Software Visibility is an optional feature that enables a
> Root Port to make CRS visible to software by returning a special data value
> to complete a config read.
>
> Clarify a comment to say that it is "CRS SV", not "CRS", that can be
> enabled.
Applied to pci/misc, thanks!
[1/1] PCI: xgene: Fix CRS SV comment
https://git.kernel.org/lpieralisi/pci/c/cc4a08cd09
Thanks,
Lorenzo
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] PCI: xgene: Fix CRS SV comment
@ 2021-01-28 10:47 ` Lorenzo Pieralisi
0 siblings, 0 replies; 4+ messages in thread
From: Lorenzo Pieralisi @ 2021-01-28 10:47 UTC (permalink / raw)
To: Bjorn Helgaas, Rob Herring, Toan Le
Cc: Bjorn Helgaas, linux-pci, Lorenzo Pieralisi, linux-arm-kernel
On Tue, 26 Jan 2021 15:35:03 -0600, Bjorn Helgaas wrote:
> Configuration Request Retry Status ("CRS") must be supported by all PCIe
> devices. CRS Software Visibility is an optional feature that enables a
> Root Port to make CRS visible to software by returning a special data value
> to complete a config read.
>
> Clarify a comment to say that it is "CRS SV", not "CRS", that can be
> enabled.
Applied to pci/misc, thanks!
[1/1] PCI: xgene: Fix CRS SV comment
https://git.kernel.org/lpieralisi/pci/c/cc4a08cd09
Thanks,
Lorenzo
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-01-28 10:49 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-01-26 21:35 [PATCH] PCI: xgene: Fix CRS SV comment Bjorn Helgaas
2021-01-26 21:35 ` Bjorn Helgaas
2021-01-28 10:47 ` Lorenzo Pieralisi
2021-01-28 10:47 ` Lorenzo Pieralisi
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