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From: Jon Hunter <jonathanh@nvidia.com>
To: Manikanta Maddireddy <mmaddireddy@nvidia.com>,
	<thierry.reding@gmail.com>, <bhelgaas@google.com>,
	<robh+dt@kernel.org>, <mark.rutland@arm.com>,
	<lorenzo.pieralisi@arm.com>, <vidyas@nvidia.com>
Cc: <linux-tegra@vger.kernel.org>, <linux-pci@vger.kernel.org>,
	<devicetree@vger.kernel.org>
Subject: Re: [PATCH V6 26/27] PCI: tegra: Add support for GPIO based PERST#
Date: Thu, 4 Jul 2019 15:48:25 +0100
Message-ID: <a4ddd0a3-f0b4-23de-fb0e-91a417d20362@nvidia.com> (raw)
In-Reply-To: <20190618180206.4908-27-mmaddireddy@nvidia.com>


On 18/06/2019 19:02, Manikanta Maddireddy wrote:
> Tegra PCIe has fixed per port SFIO line to signal PERST#, which can be
> controlled by AFI port register. However, if a platform routes a different
> GPIO to the PCIe slot, then port register cannot control it. Add support
> for GPIO based PERST# signal for such platforms. GPIO number comes from per
> port PCIe device tree node. PCIe driver probe doesn't fail if per port
> "reset-gpios" property is not populated, make sure that DT property is not
> missed for such platforms.

Really? So how come on Jetson TK1 I see ...

[    1.073165] tegra-pcie 1003000.pcie: failed to get reset GPIO: -2


[    1.073210] tegra-pcie: probe of 1003000.pcie failed with error -2

And now ethernet is broken? Why has this not been tested on all Tegra
platforms? There is no reason why code submitted to upstream by us
(people at NVIDIA) have not tested this on our internal test farm. This
is disappointing.

> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
> Acked-by: Thierry Reding <treding@nvidia.com>
> ---
> V6: No change
> 
> V5:
> * Updated reset gpio toggle logic to reflect active low usage
> * Replaced kasprintf() with devm_kasprintf()
> * Updated commit message with more information.
> 
> V4: Using devm_gpiod_get_from_of_node() to get reset-gpios
> 
> V3: Using helper function to get reset-gpios
> 
> V2: Using standard "reset-gpio" property
> 
>  drivers/pci/controller/pci-tegra.c | 45 ++++++++++++++++++++++++++----
>  1 file changed, 39 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
> index d2841532ff0e..a819bc087a05 100644
> --- a/drivers/pci/controller/pci-tegra.c
> +++ b/drivers/pci/controller/pci-tegra.c
> @@ -17,6 +17,7 @@
>  #include <linux/debugfs.h>
>  #include <linux/delay.h>
>  #include <linux/export.h>
> +#include <linux/gpio.h>
>  #include <linux/interrupt.h>
>  #include <linux/iopoll.h>
>  #include <linux/irq.h>
> @@ -399,6 +400,8 @@ struct tegra_pcie_port {
>  	unsigned int lanes;
>  
>  	struct phy **phys;
> +
> +	struct gpio_desc *reset_gpio;
>  };
>  
>  struct tegra_pcie_bus {
> @@ -544,15 +547,23 @@ static void tegra_pcie_port_reset(struct tegra_pcie_port *port)
>  	unsigned long value;
>  
>  	/* pulse reset signal */
> -	value = afi_readl(port->pcie, ctrl);
> -	value &= ~AFI_PEX_CTRL_RST;
> -	afi_writel(port->pcie, value, ctrl);
> +	if (port->reset_gpio) {
> +		gpiod_set_value(port->reset_gpio, 1);
> +	} else {
> +		value = afi_readl(port->pcie, ctrl);
> +		value &= ~AFI_PEX_CTRL_RST;
> +		afi_writel(port->pcie, value, ctrl);
> +	}
>  
>  	usleep_range(1000, 2000);
>  
> -	value = afi_readl(port->pcie, ctrl);
> -	value |= AFI_PEX_CTRL_RST;
> -	afi_writel(port->pcie, value, ctrl);
> +	if (port->reset_gpio) {
> +		gpiod_set_value(port->reset_gpio, 0);
> +	} else {
> +		value = afi_readl(port->pcie, ctrl);
> +		value |= AFI_PEX_CTRL_RST;
> +		afi_writel(port->pcie, value, ctrl);
> +	}
>  }
>  
>  static void tegra_pcie_enable_rp_features(struct tegra_pcie_port *port)
> @@ -2199,6 +2210,7 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
>  		struct tegra_pcie_port *rp;
>  		unsigned int index;
>  		u32 value;
> +		char *label;
>  
>  		err = of_pci_get_devfn(port);
>  		if (err < 0) {
> @@ -2257,6 +2269,27 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
>  		if (IS_ERR(rp->base))
>  			return PTR_ERR(rp->base);
>  
> +		label = devm_kasprintf(dev, GFP_KERNEL, "pex-reset-%u", index);
> +		if (!label) {
> +			dev_err(dev, "failed to create reset GPIO label\n");
> +			return -ENOMEM;
> +		}
> +
> +		/*
> +		 * Returns null if reset-gpios property is not populated and
> +		 * fall back to using AFI per port register to toggle PERST#
> +		 * SFIO line.
> +		 */
> +		rp->reset_gpio = devm_gpiod_get_from_of_node(dev, port,
> +							     "reset-gpios", 0,
> +							     GPIOD_OUT_LOW,
> +							     label);
> +		if (IS_ERR(rp->reset_gpio)) {
> +			err = PTR_ERR(rp->reset_gpio);
> +			dev_err(dev, "failed to get reset GPIO: %d\n", err);
> +			return err;
> +		}
> +

So I believe that we can just remove the above. I will give it a test
and see.

Cheers
Jon

-- 
nvpublic

  reply index

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-18 18:01 [PATCH V6 00/27] Enable Tegra PCIe root port features Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 01/27] soc/tegra: pmc: Export tegra_powergate_power_on() Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 02/27] PCI: tegra: Handle failure cases in tegra_pcie_power_on() Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 03/27] PCI: tegra: Rearrange Tegra PCIe driver functions Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 04/27] PCI: tegra: Mask AFI_INTR in runtime suspend Manikanta Maddireddy
2019-06-20 14:27   ` Lorenzo Pieralisi
2019-06-20 14:46     ` Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 05/27] PCI: tegra: Fix PCIe host power up sequence Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 06/27] PCI: tegra: Add PCIe Gen2 link speed support Manikanta Maddireddy
2019-06-20 14:32   ` Lorenzo Pieralisi
2019-06-20 14:57     ` Manikanta Maddireddy
2019-06-20 15:22       ` Lorenzo Pieralisi
2019-06-18 18:01 ` [PATCH V6 07/27] PCI: tegra: Advertise PCIe Advanced Error Reporting (AER) capability Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 08/27] PCI: tegra: Program UPHY electrical settings for Tegra210 Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 09/27] PCI: tegra: Enable opportunistic UpdateFC and ACK Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 10/27] PCI: tegra: Disable AFI dynamic clock gating Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 11/27] PCI: tegra: Process pending DLL transactions before entering L1 or L2 Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 12/27] PCI: tegra: Enable PCIe xclk clock clamping Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 13/27] PCI: tegra: Increase the deskew retry time Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 14/27] PCI: tegra: Add SW fixup for RAW violations Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 15/27] PCI: tegra: Update flow control timer frequency in Tegra210 Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 16/27] PCI: tegra: Set target speed as Gen1 before starting LTSSM Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 17/27] PCI: tegra: Fix PLLE power down issue due to CLKREQ# signal Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 18/27] PCI: tegra: Program AFI_CACHE* registers only for Tegra20 Manikanta Maddireddy
2019-06-20 16:26   ` Lorenzo Pieralisi
2019-06-20 16:35     ` Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 19/27] PCI: tegra: Change PRSNT_SENSE IRQ log to debug Manikanta Maddireddy
2019-06-18 18:01 ` [PATCH V6 20/27] PCI: tegra: Disable MSI for Tegra PCIe root port Manikanta Maddireddy
2019-06-18 19:48   ` Bjorn Helgaas
2019-06-19  3:55     ` Manikanta Maddireddy
2019-06-19  9:50       ` Lorenzo Pieralisi
2019-06-18 18:02 ` [PATCH V6 21/27] PCI: tegra: Add AFI_PEX2_CTRL reg offset as part of soc struct Manikanta Maddireddy
2019-06-18 18:02 ` [PATCH V6 22/27] dt-bindings: pci: tegra: Document PCIe DPD pinctrl optional prop Manikanta Maddireddy
2019-06-18 18:02 ` [PATCH V6 23/27] arm64: tegra: Add PEX DPD states as pinctrl properties Manikanta Maddireddy
2019-06-20 10:14   ` Thierry Reding
2019-06-18 18:02 ` [PATCH V6 24/27] PCI: tegra: Put PEX CLK & BIAS pads in DPD mode Manikanta Maddireddy
2019-06-18 18:02 ` [PATCH V6 25/27] PCI: Add DT binding for "reset-gpios" property Manikanta Maddireddy
2019-06-18 18:02 ` [PATCH V6 26/27] PCI: tegra: Add support for GPIO based PERST# Manikanta Maddireddy
2019-07-04 14:48   ` Jon Hunter [this message]
2019-07-04 15:29     ` Manikanta Maddireddy
2019-07-04 17:23       ` Jon Hunter
2019-06-18 18:02 ` [PATCH V6 27/27] PCI: tegra: Change link retry log level to debug Manikanta Maddireddy
2019-06-20 10:25 ` [PATCH V6 00/27] Enable Tegra PCIe root port features Thierry Reding
2019-06-20 10:53   ` Lorenzo Pieralisi
2019-06-20 11:14     ` Thierry Reding
2019-06-20 16:46 ` Lorenzo Pieralisi
2019-06-20 17:23   ` Manikanta Maddireddy

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