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* [PATCH] PCI: qcom: Don't deassert reset GPIO during probe
@ 2019-01-25 23:26 Bjorn Andersson
  2019-02-08 14:54 ` Stanimir Varbanov
  2019-02-13 15:23 ` Lorenzo Pieralisi
  0 siblings, 2 replies; 5+ messages in thread
From: Bjorn Andersson @ 2019-01-25 23:26 UTC (permalink / raw)
  To: Stanimir Varbanov, Lorenzo Pieralisi, Bjorn Helgaas
  Cc: linux-pci, linux-arm-msm, linux-kernel, Khasim Syed Mohammed,
	Niklas Cassel, stable

Acquiring the reset GPIO low means that reset is being deasserted, this
is followed almost immediately with qcom_pcie_host_init() asserting it,
initializing it and then finally deasserting it again, for the link to
come up.

Some PCIe devices requires a minimum time between the initial deassert
and subsequent reset cycles. In a platform that boots with the reset
GPIO asserted this requirement is being violated by this deassert/assert
pulse.

Acquiring the reset GPIO high will prevent this by matching the state to
the subsequent asserted state.

Cc: stable@vger.kernel.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index d185ea5fe996..a7f703556790 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1228,7 +1228,7 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 
 	pcie->ops = of_device_get_match_data(dev);
 
-	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_LOW);
+	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH);
 	if (IS_ERR(pcie->reset)) {
 		ret = PTR_ERR(pcie->reset);
 		goto err_pm_runtime_put;
-- 
2.18.0


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

* Re: [PATCH] PCI: qcom: Don't deassert reset GPIO during probe
  2019-01-25 23:26 [PATCH] PCI: qcom: Don't deassert reset GPIO during probe Bjorn Andersson
@ 2019-02-08 14:54 ` Stanimir Varbanov
  2019-02-13 15:23 ` Lorenzo Pieralisi
  1 sibling, 0 replies; 5+ messages in thread
From: Stanimir Varbanov @ 2019-02-08 14:54 UTC (permalink / raw)
  To: Bjorn Andersson, Lorenzo Pieralisi, Bjorn Helgaas
  Cc: linux-pci, linux-arm-msm, linux-kernel, Khasim Syed Mohammed,
	Niklas Cassel, stable

Hi Bjorn,

Thanks for the patch!

On 1/26/19 1:26 AM, Bjorn Andersson wrote:
> Acquiring the reset GPIO low means that reset is being deasserted, this
> is followed almost immediately with qcom_pcie_host_init() asserting it,
> initializing it and then finally deasserting it again, for the link to
> come up.
> 
> Some PCIe devices requires a minimum time between the initial deassert
> and subsequent reset cycles. In a platform that boots with the reset
> GPIO asserted this requirement is being violated by this deassert/assert
> pulse.
> 
> Acquiring the reset GPIO high will prevent this by matching the state to
> the subsequent asserted state.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>  drivers/pci/controller/dwc/pcie-qcom.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index d185ea5fe996..a7f703556790 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1228,7 +1228,7 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  
>  	pcie->ops = of_device_get_match_data(dev);
>  
> -	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_LOW);
> +	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH);
>  	if (IS_ERR(pcie->reset)) {
>  		ret = PTR_ERR(pcie->reset);
>  		goto err_pm_runtime_put;
> 

Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>

-- 
regards,
Stan

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

* Re: [PATCH] PCI: qcom: Don't deassert reset GPIO during probe
  2019-01-25 23:26 [PATCH] PCI: qcom: Don't deassert reset GPIO during probe Bjorn Andersson
  2019-02-08 14:54 ` Stanimir Varbanov
@ 2019-02-13 15:23 ` Lorenzo Pieralisi
  2019-02-19  5:16   ` Bjorn Andersson
  1 sibling, 1 reply; 5+ messages in thread
From: Lorenzo Pieralisi @ 2019-02-13 15:23 UTC (permalink / raw)
  To: Bjorn Andersson
  Cc: Stanimir Varbanov, Bjorn Helgaas, linux-pci, linux-arm-msm,
	linux-kernel, Khasim Syed Mohammed, Niklas Cassel, stable

On Fri, Jan 25, 2019 at 03:26:16PM -0800, Bjorn Andersson wrote:
> Acquiring the reset GPIO low means that reset is being deasserted, this
> is followed almost immediately with qcom_pcie_host_init() asserting it,
> initializing it and then finally deasserting it again, for the link to
> come up.
> 
> Some PCIe devices requires a minimum time between the initial deassert
> and subsequent reset cycles. In a platform that boots with the reset
> GPIO asserted this requirement is being violated by this deassert/assert
> pulse.
> 
> Acquiring the reset GPIO high will prevent this by matching the state to
> the subsequent asserted state.
> 
> Cc: stable@vger.kernel.org

Missing Fixes: tag, please provide me one so that I can proceed.

Lorenzo

> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>  drivers/pci/controller/dwc/pcie-qcom.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index d185ea5fe996..a7f703556790 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1228,7 +1228,7 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  
>  	pcie->ops = of_device_get_match_data(dev);
>  
> -	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_LOW);
> +	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH);
>  	if (IS_ERR(pcie->reset)) {
>  		ret = PTR_ERR(pcie->reset);
>  		goto err_pm_runtime_put;
> -- 
> 2.18.0
> 

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

* Re: [PATCH] PCI: qcom: Don't deassert reset GPIO during probe
  2019-02-13 15:23 ` Lorenzo Pieralisi
@ 2019-02-19  5:16   ` Bjorn Andersson
  2019-02-19 11:10     ` Lorenzo Pieralisi
  0 siblings, 1 reply; 5+ messages in thread
From: Bjorn Andersson @ 2019-02-19  5:16 UTC (permalink / raw)
  To: Lorenzo Pieralisi
  Cc: Stanimir Varbanov, Bjorn Helgaas, linux-pci, linux-arm-msm,
	linux-kernel, Khasim Syed Mohammed, Niklas Cassel, stable

On Wed 13 Feb 07:23 PST 2019, Lorenzo Pieralisi wrote:

> On Fri, Jan 25, 2019 at 03:26:16PM -0800, Bjorn Andersson wrote:
> > Acquiring the reset GPIO low means that reset is being deasserted, this
> > is followed almost immediately with qcom_pcie_host_init() asserting it,
> > initializing it and then finally deasserting it again, for the link to
> > come up.
> > 
> > Some PCIe devices requires a minimum time between the initial deassert
> > and subsequent reset cycles. In a platform that boots with the reset
> > GPIO asserted this requirement is being violated by this deassert/assert
> > pulse.
> > 
> > Acquiring the reset GPIO high will prevent this by matching the state to
> > the subsequent asserted state.
> > 
> > Cc: stable@vger.kernel.org
> 
> Missing Fixes: tag, please provide me one so that I can proceed.
> 

This applies to the original commit introducing this driver, so:

Fixes: 82a823833f4e ("PCI: qcom: Add Qualcomm PCIe controller driver")

Regards,
Bjorn

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

* Re: [PATCH] PCI: qcom: Don't deassert reset GPIO during probe
  2019-02-19  5:16   ` Bjorn Andersson
@ 2019-02-19 11:10     ` Lorenzo Pieralisi
  0 siblings, 0 replies; 5+ messages in thread
From: Lorenzo Pieralisi @ 2019-02-19 11:10 UTC (permalink / raw)
  To: Bjorn Andersson
  Cc: Stanimir Varbanov, Bjorn Helgaas, linux-pci, linux-arm-msm,
	linux-kernel, Khasim Syed Mohammed, Niklas Cassel, stable

On Mon, Feb 18, 2019 at 09:16:03PM -0800, Bjorn Andersson wrote:
> On Wed 13 Feb 07:23 PST 2019, Lorenzo Pieralisi wrote:
> 
> > On Fri, Jan 25, 2019 at 03:26:16PM -0800, Bjorn Andersson wrote:
> > > Acquiring the reset GPIO low means that reset is being deasserted, this
> > > is followed almost immediately with qcom_pcie_host_init() asserting it,
> > > initializing it and then finally deasserting it again, for the link to
> > > come up.
> > > 
> > > Some PCIe devices requires a minimum time between the initial deassert
> > > and subsequent reset cycles. In a platform that boots with the reset
> > > GPIO asserted this requirement is being violated by this deassert/assert
> > > pulse.
> > > 
> > > Acquiring the reset GPIO high will prevent this by matching the state to
> > > the subsequent asserted state.
> > > 
> > > Cc: stable@vger.kernel.org
> > 
> > Missing Fixes: tag, please provide me one so that I can proceed.
> > 
> 
> This applies to the original commit introducing this driver, so:
> 
> Fixes: 82a823833f4e ("PCI: qcom: Add Qualcomm PCIe controller driver")

Applied to pci/dwc for v5.1, thanks.

Lorenzo

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

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Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2019-01-25 23:26 [PATCH] PCI: qcom: Don't deassert reset GPIO during probe Bjorn Andersson
2019-02-08 14:54 ` Stanimir Varbanov
2019-02-13 15:23 ` Lorenzo Pieralisi
2019-02-19  5:16   ` Bjorn Andersson
2019-02-19 11:10     ` Lorenzo Pieralisi

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