2016-10-14 21:55:40

by Niklas Cassel

[permalink] [raw]
Subject: [PATCH] PCI: designware: check for iATU unroll support after initializing host

From: Niklas Cassel <[email protected]>

dw_pcie_iatu_unroll_enabled reads a dbi_base register.
Reading any dbi_base register before pp->ops->host_init has been called
causes "imprecise external abort" on platforms like ARTPEC-6, where the
PCIe module is disabled at boot and first enabled in pp->ops->host_init.
Move dw_pcie_iatu_unroll_enabled to dw_pcie_setup_rc, since it is after
pp->ops->host_init, but before pp->iatu_unroll_enabled is actually used.

Fixes: a0601a470537 ("PCI: designware: Add iATU Unroll feature")
Signed-off-by: Niklas Cassel <[email protected]>
---
drivers/pci/host/pcie-designware.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
index 035f50c03281..bed19994c1e9 100644
--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -637,8 +637,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
}
}

- pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
-
if (pp->ops->host_init)
pp->ops->host_init(pp);

@@ -809,6 +807,11 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
{
u32 val;

+ /* get iATU unroll support */
+ pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
+ dev_dbg(pp->dev, "iATU unroll: %s\n",
+ pp->iatu_unroll_enabled ? "enabled" : "disabled");
+
/* set the number of lanes */
val = dw_pcie_readl_rc(pp, PCIE_PORT_LINK_CONTROL);
val &= ~PORT_LINK_MODE_MASK;
--
2.1.4


2016-10-17 14:34:53

by Joao Pinto

[permalink] [raw]
Subject: Re: [PATCH] PCI: designware: check for iATU unroll support after initializing host


On 10/14/2016 10:54 PM, Niklas Cassel wrote:
> From: Niklas Cassel <[email protected]>
>
> dw_pcie_iatu_unroll_enabled reads a dbi_base register.
> Reading any dbi_base register before pp->ops->host_init has been called
> causes "imprecise external abort" on platforms like ARTPEC-6, where the
> PCIe module is disabled at boot and first enabled in pp->ops->host_init.
> Move dw_pcie_iatu_unroll_enabled to dw_pcie_setup_rc, since it is after
> pp->ops->host_init, but before pp->iatu_unroll_enabled is actually used.
>
> Fixes: a0601a470537 ("PCI: designware: Add iATU Unroll feature")
> Signed-off-by: Niklas Cassel <[email protected]>
> ---
> drivers/pci/host/pcie-designware.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
> index 035f50c03281..bed19994c1e9 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -637,8 +637,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
> }
> }
>
> - pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
> -
> if (pp->ops->host_init)
> pp->ops->host_init(pp);
>
> @@ -809,6 +807,11 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
> {
> u32 val;
>
> + /* get iATU unroll support */
> + pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
> + dev_dbg(pp->dev, "iATU unroll: %s\n",
> + pp->iatu_unroll_enabled ? "enabled" : "disabled");
> +
> /* set the number of lanes */
> val = dw_pcie_readl_rc(pp, PCIE_PORT_LINK_CONTROL);
> val &= ~PORT_LINK_MODE_MASK;
>

Acked-by: Joao Pinto <[email protected]>

Thanks
Joao

2016-10-29 14:01:58

by James Le Cuirot

[permalink] [raw]
Subject: Re: PCI: designware: check for iATU unroll support after initializing host

On Fri, 14 Oct 2016 23:54:55 +0200
Niklas Cassel <[email protected]> wrote:

> From: Niklas Cassel <[email protected]>
>
> dw_pcie_iatu_unroll_enabled reads a dbi_base register.
> Reading any dbi_base register before pp->ops->host_init has been
> called causes "imprecise external abort" on platforms like ARTPEC-6,
> where the PCIe module is disabled at boot and first enabled in
> pp->ops->host_init. Move dw_pcie_iatu_unroll_enabled to
> dw_pcie_setup_rc, since it is after pp->ops->host_init, but before
> pp->iatu_unroll_enabled is actually used.
>
> Fixes: a0601a470537 ("PCI: designware: Add iATU Unroll feature")
> Signed-off-by: Niklas Cassel <[email protected]>
> Acked-by: Joao Pinto <[email protected]>

Tested-by: James Le Cuirot <[email protected]>

My Utilite Pro was failing to boot and this fixed it so thanks.

> ---
> drivers/pci/host/pcie-designware.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/host/pcie-designware.c
> b/drivers/pci/host/pcie-designware.c index 035f50c03281..bed19994c1e9
> 100644 --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -637,8 +637,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
> }
> }
>
> - pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
> -
> if (pp->ops->host_init)
> pp->ops->host_init(pp);
>
> @@ -809,6 +807,11 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
> {
> u32 val;
>
> + /* get iATU unroll support */
> + pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
> + dev_dbg(pp->dev, "iATU unroll: %s\n",
> + pp->iatu_unroll_enabled ? "enabled" : "disabled");
> +
> /* set the number of lanes */
> val = dw_pcie_readl_rc(pp, PCIE_PORT_LINK_CONTROL);
> val &= ~PORT_LINK_MODE_MASK;


Attachments:
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2016-11-02 15:48:06

by Olof Johansson

[permalink] [raw]
Subject: Re: [PATCH] PCI: designware: check for iATU unroll support after initializing host

Hi,

On Fri, Oct 14, 2016 at 2:54 PM, Niklas Cassel <[email protected]> wrote:
> From: Niklas Cassel <[email protected]>
>
> dw_pcie_iatu_unroll_enabled reads a dbi_base register.
> Reading any dbi_base register before pp->ops->host_init has been called
> causes "imprecise external abort" on platforms like ARTPEC-6, where the
> PCIe module is disabled at boot and first enabled in pp->ops->host_init.
> Move dw_pcie_iatu_unroll_enabled to dw_pcie_setup_rc, since it is after
> pp->ops->host_init, but before pp->iatu_unroll_enabled is actually used.
>
> Fixes: a0601a470537 ("PCI: designware: Add iATU Unroll feature")
> Signed-off-by: Niklas Cassel <[email protected]>

This fixes the regression I've seen on i.MX6 devices in my board farm as well.

Acked-by: Olof Johansson <[email protected]>

Bjorn, can you please pick this up and get it sent up for 4.9-rc soon?
I worry about losing bisectability if this remains broken for a while.
Thanks!


-Olof

2016-11-02 16:26:47

by Bjorn Helgaas

[permalink] [raw]
Subject: Re: [PATCH] PCI: designware: check for iATU unroll support after initializing host

On Fri, Oct 14, 2016 at 11:54:55PM +0200, Niklas Cassel wrote:
> From: Niklas Cassel <[email protected]>
>
> dw_pcie_iatu_unroll_enabled reads a dbi_base register.
> Reading any dbi_base register before pp->ops->host_init has been called
> causes "imprecise external abort" on platforms like ARTPEC-6, where the
> PCIe module is disabled at boot and first enabled in pp->ops->host_init.
> Move dw_pcie_iatu_unroll_enabled to dw_pcie_setup_rc, since it is after
> pp->ops->host_init, but before pp->iatu_unroll_enabled is actually used.
>
> Fixes: a0601a470537 ("PCI: designware: Add iATU Unroll feature")
> Signed-off-by: Niklas Cassel <[email protected]>

Applied to for-linus for v4.9 with acks and tested-by from Joao, Olof,
and James, thanks!

> ---
> drivers/pci/host/pcie-designware.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
> index 035f50c03281..bed19994c1e9 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -637,8 +637,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
> }
> }
>
> - pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
> -
> if (pp->ops->host_init)
> pp->ops->host_init(pp);
>
> @@ -809,6 +807,11 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
> {
> u32 val;
>
> + /* get iATU unroll support */
> + pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
> + dev_dbg(pp->dev, "iATU unroll: %s\n",
> + pp->iatu_unroll_enabled ? "enabled" : "disabled");
> +
> /* set the number of lanes */
> val = dw_pcie_readl_rc(pp, PCIE_PORT_LINK_CONTROL);
> val &= ~PORT_LINK_MODE_MASK;
> --
> 2.1.4
>
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