[EXT] [PATCH 2/2] arm64: a37xx: pci: Assert PERST# signal when unloading driver

[Kostya Porotchkin]

> -----Original Message-----
> From: Pali Rohár <pali at kernel.org>
> Sent: Wednesday, August 19, 2020 16:57
> To: Stefan Roese <sr at denx.de>; Kostya Porotchkin <kostap at marvell.com>
> Cc: u-boot at lists.denx.de
> Subject: [EXT] [PATCH 2/2] arm64: a37xx: pci: Assert PERST# signal when
> unloading driver
> 
> External Email
> 
> ----------------------------------------------------------------------
> This change ensures that PCIe card is put into reset state when U-Boot stops
> using it.
> 
> DM_FLAG_OS_PREPARE ensures that U-Boot executes driver's remove
> callback prior booting Linux kernel.
> 
> Linux kernel pci-aardvark driver needs to reset PCIe card via PERST# signal
> prior initializing it. If it does not issue reset then some PCIe cards (specially
> Compex WiFi cards) are not detected at all.
> 
> Putting PCIe card into reset state prior booting Linux kernel would ensure
> that card would be properly reset at time when Linux kernel starts initializing
> pci-aardvark driver.
> 
> Signed-off-by: Pali Rohár <pali at kernel.org>
Reviewed-by: Konstantin Porotchkin <kostap at marvell.com>

> ---
>  drivers/pci/pci-aardvark.c | 27 +++++++++++++++++++++------
>  1 file changed, 21 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/pci-aardvark.c b/drivers/pci/pci-aardvark.c index
> 5b3f23c184..8996be5309 100644
> --- a/drivers/pci/pci-aardvark.c
> +++ b/drivers/pci/pci-aardvark.c
> @@ -148,6 +148,9 @@ struct pcie_advk {
>  	void           *base;
>  	int            first_busno;
>  	struct udevice *dev;
> +#if CONFIG_IS_ENABLED(DM_GPIO)
> +	struct gpio_desc reset_gpio;
> +#endif
>  };
> 
>  static inline void advk_writel(struct pcie_advk *pcie, uint val, uint reg) @@ -
> 614,9 +617,7 @@ static int pcie_advk_probe(struct udevice *dev)
>  	struct pcie_advk *pcie = dev_get_priv(dev);
> 
>  #if CONFIG_IS_ENABLED(DM_GPIO)
> -	struct gpio_desc reset_gpio;
> -
> -	gpio_request_by_name(dev, "reset-gpios", 0, &reset_gpio,
> +	gpio_request_by_name(dev, "reset-gpios", 0, &pcie->reset_gpio,
>  			     GPIOD_IS_OUT);
>  	/*
>  	 * Issue reset to add-in card through the dedicated GPIO.
> @@ -631,11 +632,11 @@ static int pcie_advk_probe(struct udevice *dev)
>  	 *     possible before PCIe PHY initialization. Moreover, the PCIe
>  	 *     clock should be gated as well.
>  	 */
> -	if (dm_gpio_is_valid(&reset_gpio)) {
> +	if (dm_gpio_is_valid(&pcie->reset_gpio)) {
>  		dev_dbg(pcie->dev, "Toggle PCIE Reset GPIO ...\n");
> -		dm_gpio_set_value(&reset_gpio, 1);
> +		dm_gpio_set_value(&pcie->reset_gpio, 1);
>  		mdelay(200);
> -		dm_gpio_set_value(&reset_gpio, 0);
> +		dm_gpio_set_value(&pcie->reset_gpio, 0);
>  	}
>  #else
>  	dev_dbg(pcie->dev, "PCIE Reset on GPIO support is missing\n"); @@
> -647,6 +648,18 @@ static int pcie_advk_probe(struct udevice *dev)
>  	return pcie_advk_setup_hw(pcie);
>  }
> 
> +static int pcie_advk_remove(struct udevice *dev) { #if
> +CONFIG_IS_ENABLED(DM_GPIO)
> +	struct pcie_advk *pcie = dev_get_priv(dev);
> +
> +	if (dm_gpio_is_valid(&pcie->reset_gpio))
> +		dm_gpio_set_value(&pcie->reset_gpio, 1); #endif /*
> DM_GPIO */
> +
> +	return 0;
> +}
> +
>  /**
>   * pcie_advk_ofdata_to_platdata() - Translate from DT to device state
>   *
> @@ -687,5 +700,7 @@ U_BOOT_DRIVER(pcie_advk) = {
>  	.ops			= &pcie_advk_ops,
>  	.ofdata_to_platdata	= pcie_advk_ofdata_to_platdata,
>  	.probe			= pcie_advk_probe,
> +	.remove			= pcie_advk_remove,
> +	.flags			= DM_FLAG_OS_PREPARE,
>  	.priv_auto_alloc_size	= sizeof(struct pcie_advk),
>  };
> --
> 2.20.1