* [PATCH v2] PCI: Add ACS errata for Pericom PI7C9X2G404 switch
@ 2021-09-09 8:09 Nathan Rossi
2021-09-09 15:39 ` Alex Williamson
2021-09-10 2:58 ` [PATCH v3] PCI: Add ACS errata for Pericom PI7C9X2G switches Nathan Rossi
0 siblings, 2 replies; 5+ messages in thread
From: Nathan Rossi @ 2021-09-09 8:09 UTC (permalink / raw)
To: linux-pci
Cc: Nathan Rossi, Nathan Rossi, Lukas Wunner, Alex Williamson, Bjorn Helgaas
From: Nathan Rossi <nathan.rossi@digi.com>
The Pericom PI7C9X2G404 PCIe switch has an errata for ACS P2P Request
Redirect behaviour when used in the cut-through forwarding mode. The
recommended work around for this issue is to use the switch in store and
forward mode. The errata results in packets being queued and not being
delivered upstream, this can be observed as very poor downstream device
performance and/or dropped device generated data/interrupts.
This change adds a fixup specific to this switch that when enabling or
resuming the downstream port it checks if it has enabled ACS P2P Request
Redirect, and if so changes the device (via the upstream port) to use
the store and forward operating mode.
Signed-off-by: Nathan Rossi <nathan.rossi@digi.com>
---
Changes in v2:
- Added DECLARE_PCI_FIXUP_RESUME to handle applying fixup upon resume as
switch operation may have been reset or ACS configuration may have
changed
---
drivers/pci/quirks.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index e5089af8ad..5849b7046b 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5790,3 +5790,51 @@ static void apex_pci_fixup_class(struct pci_dev *pdev)
}
DECLARE_PCI_FIXUP_CLASS_HEADER(0x1ac1, 0x089a,
PCI_CLASS_NOT_DEFINED, 8, apex_pci_fixup_class);
+
+/*
+ * Pericom PI7C9X2G404 switch errata E5 - ACS P2P Request Redirect is not
+ * functional
+ *
+ * When ACS P2P Request Redirect is enabled and bandwidth is not balanced
+ * between upstream and downstream ports, packets are queued in an internal
+ * buffer until CPLD packet. The workaround is to use the switch in store and
+ * forward mode.
+ */
+#define PI7C9X2G404_MODE_REG 0x74
+#define PI7C9X2G404_STORE_FORWARD_MODE BIT(0)
+static void pci_fixup_pericom_acs_store_forward(struct pci_dev *pdev)
+{
+ struct pci_dev *upstream;
+ u16 val;
+
+ /* Downstream ports only */
+ if (pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM)
+ return;
+
+ /* Check for ACS P2P Request Redirect use */
+ if (!pdev->acs_cap)
+ return;
+ pci_read_config_word(pdev, pdev->acs_cap + PCI_ACS_CTRL, &val);
+ if (!(val & PCI_ACS_RR))
+ return;
+
+ upstream = pci_upstream_bridge(pdev);
+ if (!upstream)
+ return;
+
+ pci_read_config_word(upstream, PI7C9X2G404_MODE_REG, &val);
+ if (!(val & PI7C9X2G404_STORE_FORWARD_MODE)) {
+ pci_info(upstream, "Setting PI7C9X2G404 store-forward mode\n");
+ /* Enable store-foward mode */
+ pci_write_config_word(upstream, PI7C9X2G404_MODE_REG, val |
+ PI7C9X2G404_STORE_FORWARD_MODE);
+ }
+}
+/*
+ * Apply fixup on enable and on resume, in order to apply the fix up whenever
+ * ACS configuration changes or switch mode is reset
+ */
+DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2404,
+ pci_fixup_pericom_acs_store_forward);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2404,
+ pci_fixup_pericom_acs_store_forward);
---
2.33.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2] PCI: Add ACS errata for Pericom PI7C9X2G404 switch
2021-09-09 8:09 [PATCH v2] PCI: Add ACS errata for Pericom PI7C9X2G404 switch Nathan Rossi
@ 2021-09-09 15:39 ` Alex Williamson
2021-09-09 17:56 ` Alex Williamson
2021-09-10 2:58 ` [PATCH v3] PCI: Add ACS errata for Pericom PI7C9X2G switches Nathan Rossi
1 sibling, 1 reply; 5+ messages in thread
From: Alex Williamson @ 2021-09-09 15:39 UTC (permalink / raw)
To: Nathan Rossi; +Cc: linux-pci, Nathan Rossi, Lukas Wunner, Bjorn Helgaas
On Thu, 09 Sep 2021 08:09:27 +0000
Nathan Rossi <nathan@nathanrossi.com> wrote:
> From: Nathan Rossi <nathan.rossi@digi.com>
>
> The Pericom PI7C9X2G404 PCIe switch has an errata for ACS P2P Request
> Redirect behaviour when used in the cut-through forwarding mode. The
> recommended work around for this issue is to use the switch in store and
> forward mode. The errata results in packets being queued and not being
> delivered upstream, this can be observed as very poor downstream device
> performance and/or dropped device generated data/interrupts.
>
> This change adds a fixup specific to this switch that when enabling or
> resuming the downstream port it checks if it has enabled ACS P2P Request
> Redirect, and if so changes the device (via the upstream port) to use
> the store and forward operating mode.
>
> Signed-off-by: Nathan Rossi <nathan.rossi@digi.com>
Thanks for pursuing this! I took a stab at it[1] some time ago but I
tried to pursue link balancing, I didn't have the datasheet to realize
we could simply put the device in a different mode and blindly assumed
the mode was inherit to the unbalanced link config. Link balancing
turned out to be more complicated than I cared or had time to pursue.
Also related to this device, there is a kernel bz for this issue that
might provide more details[2], Bjorn will probably want to add that
reference to the commit log.
I'll see if I can find the card from that bz to test here. Thanks,
Alex
[1]https://lore.kernel.org/all/20161026175156.23495.12980.stgit@gimli.home/
[2]https://bugzilla.kernel.org/show_bug.cgi?id=177471
> ---
> Changes in v2:
> - Added DECLARE_PCI_FIXUP_RESUME to handle applying fixup upon resume as
> switch operation may have been reset or ACS configuration may have
> changed
> ---
> drivers/pci/quirks.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 48 insertions(+)
>
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index e5089af8ad..5849b7046b 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5790,3 +5790,51 @@ static void apex_pci_fixup_class(struct pci_dev *pdev)
> }
> DECLARE_PCI_FIXUP_CLASS_HEADER(0x1ac1, 0x089a,
> PCI_CLASS_NOT_DEFINED, 8, apex_pci_fixup_class);
> +
> +/*
> + * Pericom PI7C9X2G404 switch errata E5 - ACS P2P Request Redirect is not
> + * functional
> + *
> + * When ACS P2P Request Redirect is enabled and bandwidth is not balanced
> + * between upstream and downstream ports, packets are queued in an internal
> + * buffer until CPLD packet. The workaround is to use the switch in store and
> + * forward mode.
> + */
> +#define PI7C9X2G404_MODE_REG 0x74
> +#define PI7C9X2G404_STORE_FORWARD_MODE BIT(0)
> +static void pci_fixup_pericom_acs_store_forward(struct pci_dev *pdev)
> +{
> + struct pci_dev *upstream;
> + u16 val;
> +
> + /* Downstream ports only */
> + if (pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM)
> + return;
> +
> + /* Check for ACS P2P Request Redirect use */
> + if (!pdev->acs_cap)
> + return;
> + pci_read_config_word(pdev, pdev->acs_cap + PCI_ACS_CTRL, &val);
> + if (!(val & PCI_ACS_RR))
> + return;
> +
> + upstream = pci_upstream_bridge(pdev);
> + if (!upstream)
> + return;
> +
> + pci_read_config_word(upstream, PI7C9X2G404_MODE_REG, &val);
> + if (!(val & PI7C9X2G404_STORE_FORWARD_MODE)) {
> + pci_info(upstream, "Setting PI7C9X2G404 store-forward mode\n");
> + /* Enable store-foward mode */
> + pci_write_config_word(upstream, PI7C9X2G404_MODE_REG, val |
> + PI7C9X2G404_STORE_FORWARD_MODE);
> + }
> +}
> +/*
> + * Apply fixup on enable and on resume, in order to apply the fix up whenever
> + * ACS configuration changes or switch mode is reset
> + */
> +DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2404,
> + pci_fixup_pericom_acs_store_forward);
> +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2404,
> + pci_fixup_pericom_acs_store_forward);
> ---
> 2.33.0
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] PCI: Add ACS errata for Pericom PI7C9X2G404 switch
2021-09-09 15:39 ` Alex Williamson
@ 2021-09-09 17:56 ` Alex Williamson
0 siblings, 0 replies; 5+ messages in thread
From: Alex Williamson @ 2021-09-09 17:56 UTC (permalink / raw)
To: Nathan Rossi; +Cc: linux-pci, Nathan Rossi, Lukas Wunner, Bjorn Helgaas
On Thu, 9 Sep 2021 09:39:11 -0600
Alex Williamson <alex.williamson@redhat.com> wrote:
> On Thu, 09 Sep 2021 08:09:27 +0000
> Nathan Rossi <nathan@nathanrossi.com> wrote:
>
> > From: Nathan Rossi <nathan.rossi@digi.com>
> >
> > The Pericom PI7C9X2G404 PCIe switch has an errata for ACS P2P Request
> > Redirect behaviour when used in the cut-through forwarding mode. The
> > recommended work around for this issue is to use the switch in store and
> > forward mode. The errata results in packets being queued and not being
> > delivered upstream, this can be observed as very poor downstream device
> > performance and/or dropped device generated data/interrupts.
> >
> > This change adds a fixup specific to this switch that when enabling or
> > resuming the downstream port it checks if it has enabled ACS P2P Request
> > Redirect, and if so changes the device (via the upstream port) to use
> > the store and forward operating mode.
> >
> > Signed-off-by: Nathan Rossi <nathan.rossi@digi.com>
>
>
> Thanks for pursuing this! I took a stab at it[1] some time ago but I
> tried to pursue link balancing, I didn't have the datasheet to realize
> we could simply put the device in a different mode and blindly assumed
> the mode was inherit to the unbalanced link config. Link balancing
> turned out to be more complicated than I cared or had time to pursue.
>
> Also related to this device, there is a kernel bz for this issue that
> might provide more details[2], Bjorn will probably want to add that
> reference to the commit log.
>
> I'll see if I can find the card from that bz to test here. Thanks,
Tested against the troublesome dual-port NIC mentioned in the bz
below[2]. With VT-d enabled the NIC reports netdev timeouts, fails to
DHCP an IP for some time. With this patch I see the info message in
dmesg reporting store-forward mode is enabled and both ports appear to
work normally with no netdev timeouts.
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Thanks!
Alex
> [1]https://lore.kernel.org/all/20161026175156.23495.12980.stgit@gimli.home/
> [2]https://bugzilla.kernel.org/show_bug.cgi?id=177471
>
> > ---
> > Changes in v2:
> > - Added DECLARE_PCI_FIXUP_RESUME to handle applying fixup upon resume as
> > switch operation may have been reset or ACS configuration may have
> > changed
> > ---
> > drivers/pci/quirks.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 48 insertions(+)
> >
> > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > index e5089af8ad..5849b7046b 100644
> > --- a/drivers/pci/quirks.c
> > +++ b/drivers/pci/quirks.c
> > @@ -5790,3 +5790,51 @@ static void apex_pci_fixup_class(struct pci_dev *pdev)
> > }
> > DECLARE_PCI_FIXUP_CLASS_HEADER(0x1ac1, 0x089a,
> > PCI_CLASS_NOT_DEFINED, 8, apex_pci_fixup_class);
> > +
> > +/*
> > + * Pericom PI7C9X2G404 switch errata E5 - ACS P2P Request Redirect is not
> > + * functional
> > + *
> > + * When ACS P2P Request Redirect is enabled and bandwidth is not balanced
> > + * between upstream and downstream ports, packets are queued in an internal
> > + * buffer until CPLD packet. The workaround is to use the switch in store and
> > + * forward mode.
> > + */
> > +#define PI7C9X2G404_MODE_REG 0x74
> > +#define PI7C9X2G404_STORE_FORWARD_MODE BIT(0)
> > +static void pci_fixup_pericom_acs_store_forward(struct pci_dev *pdev)
> > +{
> > + struct pci_dev *upstream;
> > + u16 val;
> > +
> > + /* Downstream ports only */
> > + if (pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM)
> > + return;
> > +
> > + /* Check for ACS P2P Request Redirect use */
> > + if (!pdev->acs_cap)
> > + return;
> > + pci_read_config_word(pdev, pdev->acs_cap + PCI_ACS_CTRL, &val);
> > + if (!(val & PCI_ACS_RR))
> > + return;
> > +
> > + upstream = pci_upstream_bridge(pdev);
> > + if (!upstream)
> > + return;
> > +
> > + pci_read_config_word(upstream, PI7C9X2G404_MODE_REG, &val);
> > + if (!(val & PI7C9X2G404_STORE_FORWARD_MODE)) {
> > + pci_info(upstream, "Setting PI7C9X2G404 store-forward mode\n");
> > + /* Enable store-foward mode */
> > + pci_write_config_word(upstream, PI7C9X2G404_MODE_REG, val |
> > + PI7C9X2G404_STORE_FORWARD_MODE);
> > + }
> > +}
> > +/*
> > + * Apply fixup on enable and on resume, in order to apply the fix up whenever
> > + * ACS configuration changes or switch mode is reset
> > + */
> > +DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2404,
> > + pci_fixup_pericom_acs_store_forward);
> > +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2404,
> > + pci_fixup_pericom_acs_store_forward);
> > ---
> > 2.33.0
> >
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v3] PCI: Add ACS errata for Pericom PI7C9X2G switches
2021-09-09 8:09 [PATCH v2] PCI: Add ACS errata for Pericom PI7C9X2G404 switch Nathan Rossi
2021-09-09 15:39 ` Alex Williamson
@ 2021-09-10 2:58 ` Nathan Rossi
2021-09-14 21:18 ` Bjorn Helgaas
1 sibling, 1 reply; 5+ messages in thread
From: Nathan Rossi @ 2021-09-10 2:58 UTC (permalink / raw)
To: linux-pci
Cc: Nathan Rossi, Nathan Rossi, Alex Williamson, Lukas Wunner, Bjorn Helgaas
From: Nathan Rossi <nathan.rossi@digi.com>
The Pericom PI7C9X2G404/PI7C9X2G304/PI7C9X2G303 PCIe switches have an
errata for ACS P2P Request Redirect behaviour when used in the
cut-through forwarding mode. The recommended work around for this issue
is to use the switch in store and forward mode. The errata results in
packets being queued and not being delivered upstream, this can be
observed as very poor downstream device performance and/or dropped
device generated data/interrupts.
This change adds a fixup specific to this switch that when enabling or
resuming the downstream port it checks if it has enabled ACS P2P Request
Redirect, and if so changes the device (via the upstream port) to use
the store and forward operating mode.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=177471
Signed-off-by: Nathan Rossi <nathan.rossi@digi.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
---
Changes in v2:
- Added DECLARE_PCI_FIXUP_RESUME to handle applying fixup upon resume as
switch operation may have been reset or ACS configuration may have
changed
Changes in v3:
- Apply fixup to PI7C9X2G303 and PI7C9X2G304 switch models, these models
are also covered by the errata, although have not been validated
- Rename PI7C9X2G404 defines to more generic PI7C9X2Gxxx
---
drivers/pci/quirks.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index e5089af8ad..f7cbc4fa40 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5790,3 +5790,59 @@ static void apex_pci_fixup_class(struct pci_dev *pdev)
}
DECLARE_PCI_FIXUP_CLASS_HEADER(0x1ac1, 0x089a,
PCI_CLASS_NOT_DEFINED, 8, apex_pci_fixup_class);
+
+/*
+ * Pericom PI7C9X2G404/PI7C9X2G304/PI7C9X2G303 switch errata E5 - ACS P2P Request
+ * Redirect is not functional
+ *
+ * When ACS P2P Request Redirect is enabled and bandwidth is not balanced
+ * between upstream and downstream ports, packets are queued in an internal
+ * buffer until CPLD packet. The workaround is to use the switch in store and
+ * forward mode.
+ */
+#define PI7C9X2Gxxx_MODE_REG 0x74
+#define PI7C9X2Gxxx_STORE_FORWARD_MODE BIT(0)
+static void pci_fixup_pericom_acs_store_forward(struct pci_dev *pdev)
+{
+ struct pci_dev *upstream;
+ u16 val;
+
+ /* Downstream ports only */
+ if (pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM)
+ return;
+
+ /* Check for ACS P2P Request Redirect use */
+ if (!pdev->acs_cap)
+ return;
+ pci_read_config_word(pdev, pdev->acs_cap + PCI_ACS_CTRL, &val);
+ if (!(val & PCI_ACS_RR))
+ return;
+
+ upstream = pci_upstream_bridge(pdev);
+ if (!upstream)
+ return;
+
+ pci_read_config_word(upstream, PI7C9X2Gxxx_MODE_REG, &val);
+ if (!(val & PI7C9X2Gxxx_STORE_FORWARD_MODE)) {
+ pci_info(upstream, "Setting PI7C9X2Gxxx store-forward mode\n");
+ /* Enable store-foward mode */
+ pci_write_config_word(upstream, PI7C9X2Gxxx_MODE_REG, val |
+ PI7C9X2Gxxx_STORE_FORWARD_MODE);
+ }
+}
+/*
+ * Apply fixup on enable and on resume, in order to apply the fix up whenever
+ * ACS configuration changes or switch mode is reset
+ */
+DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2404,
+ pci_fixup_pericom_acs_store_forward);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2404,
+ pci_fixup_pericom_acs_store_forward);
+DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2304,
+ pci_fixup_pericom_acs_store_forward);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2304,
+ pci_fixup_pericom_acs_store_forward);
+DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2303,
+ pci_fixup_pericom_acs_store_forward);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2303,
+ pci_fixup_pericom_acs_store_forward);
---
2.33.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3] PCI: Add ACS errata for Pericom PI7C9X2G switches
2021-09-10 2:58 ` [PATCH v3] PCI: Add ACS errata for Pericom PI7C9X2G switches Nathan Rossi
@ 2021-09-14 21:18 ` Bjorn Helgaas
0 siblings, 0 replies; 5+ messages in thread
From: Bjorn Helgaas @ 2021-09-14 21:18 UTC (permalink / raw)
To: Nathan Rossi
Cc: linux-pci, Nathan Rossi, Alex Williamson, Lukas Wunner, Bjorn Helgaas
On Fri, Sep 10, 2021 at 02:58:23AM +0000, Nathan Rossi wrote:
> From: Nathan Rossi <nathan.rossi@digi.com>
>
> The Pericom PI7C9X2G404/PI7C9X2G304/PI7C9X2G303 PCIe switches have an
> errata for ACS P2P Request Redirect behaviour when used in the
> cut-through forwarding mode. The recommended work around for this issue
> is to use the switch in store and forward mode. The errata results in
> packets being queued and not being delivered upstream, this can be
> observed as very poor downstream device performance and/or dropped
> device generated data/interrupts.
>
> This change adds a fixup specific to this switch that when enabling or
> resuming the downstream port it checks if it has enabled ACS P2P Request
> Redirect, and if so changes the device (via the upstream port) to use
> the store and forward operating mode.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=177471
> Signed-off-by: Nathan Rossi <nathan.rossi@digi.com>
> Tested-by: Alex Williamson <alex.williamson@redhat.com>
Applied to pci/virtualization for v5.16, thanks!
> ---
> Changes in v2:
> - Added DECLARE_PCI_FIXUP_RESUME to handle applying fixup upon resume as
> switch operation may have been reset or ACS configuration may have
> changed
> Changes in v3:
> - Apply fixup to PI7C9X2G303 and PI7C9X2G304 switch models, these models
> are also covered by the errata, although have not been validated
> - Rename PI7C9X2G404 defines to more generic PI7C9X2Gxxx
> ---
> drivers/pci/quirks.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 56 insertions(+)
>
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index e5089af8ad..f7cbc4fa40 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5790,3 +5790,59 @@ static void apex_pci_fixup_class(struct pci_dev *pdev)
> }
> DECLARE_PCI_FIXUP_CLASS_HEADER(0x1ac1, 0x089a,
> PCI_CLASS_NOT_DEFINED, 8, apex_pci_fixup_class);
> +
> +/*
> + * Pericom PI7C9X2G404/PI7C9X2G304/PI7C9X2G303 switch errata E5 - ACS P2P Request
> + * Redirect is not functional
> + *
> + * When ACS P2P Request Redirect is enabled and bandwidth is not balanced
> + * between upstream and downstream ports, packets are queued in an internal
> + * buffer until CPLD packet. The workaround is to use the switch in store and
> + * forward mode.
> + */
> +#define PI7C9X2Gxxx_MODE_REG 0x74
> +#define PI7C9X2Gxxx_STORE_FORWARD_MODE BIT(0)
> +static void pci_fixup_pericom_acs_store_forward(struct pci_dev *pdev)
> +{
> + struct pci_dev *upstream;
> + u16 val;
> +
> + /* Downstream ports only */
> + if (pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM)
> + return;
> +
> + /* Check for ACS P2P Request Redirect use */
> + if (!pdev->acs_cap)
> + return;
> + pci_read_config_word(pdev, pdev->acs_cap + PCI_ACS_CTRL, &val);
> + if (!(val & PCI_ACS_RR))
> + return;
> +
> + upstream = pci_upstream_bridge(pdev);
> + if (!upstream)
> + return;
> +
> + pci_read_config_word(upstream, PI7C9X2Gxxx_MODE_REG, &val);
> + if (!(val & PI7C9X2Gxxx_STORE_FORWARD_MODE)) {
> + pci_info(upstream, "Setting PI7C9X2Gxxx store-forward mode\n");
> + /* Enable store-foward mode */
> + pci_write_config_word(upstream, PI7C9X2Gxxx_MODE_REG, val |
> + PI7C9X2Gxxx_STORE_FORWARD_MODE);
> + }
> +}
> +/*
> + * Apply fixup on enable and on resume, in order to apply the fix up whenever
> + * ACS configuration changes or switch mode is reset
> + */
> +DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2404,
> + pci_fixup_pericom_acs_store_forward);
> +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2404,
> + pci_fixup_pericom_acs_store_forward);
> +DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2304,
> + pci_fixup_pericom_acs_store_forward);
> +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2304,
> + pci_fixup_pericom_acs_store_forward);
> +DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_PERICOM, 0x2303,
> + pci_fixup_pericom_acs_store_forward);
> +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_PERICOM, 0x2303,
> + pci_fixup_pericom_acs_store_forward);
> ---
> 2.33.0
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-09-14 21:18 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-09 8:09 [PATCH v2] PCI: Add ACS errata for Pericom PI7C9X2G404 switch Nathan Rossi
2021-09-09 15:39 ` Alex Williamson
2021-09-09 17:56 ` Alex Williamson
2021-09-10 2:58 ` [PATCH v3] PCI: Add ACS errata for Pericom PI7C9X2G switches Nathan Rossi
2021-09-14 21:18 ` Bjorn Helgaas
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