Message-ID: <e86e613b-0811-bbed-1999-260b83351957@baylibre.com>
Date:   Wed, 15 Jan 2020 13:30:06 +0100
From:   Neil Armstrong <narmstrong@...libre.com>
To:     Remi Pommarel <repk@...plefau.lt>,
        Kishon Vijay Abraham I <kishon@...com>,
        Yue Wang <yue.wang@...ogic.com>,
        Kevin Hilman <khilman@...libre.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Rob Herring <robh+dt@...nel.org>
Cc:     Jerome Brunet <jbrunet@...libre.com>,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v4 7/7] PCI: amlogic: Use AXG PCIE and shared MIPI/PCIE
 PHYs

On 15/01/2020 13:29, Remi Pommarel wrote:
> Now that PCIE PHY has been introduced for AXG, the whole has_shared_phy
> logic can be mutualized between AXG and G12A platforms.
> 
> This also makes use of the optional MIPI/PCIE shared fonctionality PHY
> found on AXG platforms, which need to be used in order to have reliable
> PCIE communications.
> 
> Signed-off-by: Remi Pommarel <repk@...plefau.lt>
> ---
>  drivers/pci/controller/dwc/pci-meson.c | 140 ++++++++-----------------
>  1 file changed, 46 insertions(+), 94 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-meson.c b/drivers/pci/controller/dwc/pci-meson.c
> index 3772b02a5c55..309e75f554ac 100644
> --- a/drivers/pci/controller/dwc/pci-meson.c
> +++ b/drivers/pci/controller/dwc/pci-meson.c
> @@ -66,7 +66,6 @@
>  #define PORT_CLK_RATE			100000000UL
>  #define MAX_PAYLOAD_SIZE		256
>  #define MAX_READ_REQ_SIZE		256
> -#define MESON_PCIE_PHY_POWERUP		0x1c
>  #define PCIE_RESET_DELAY		500
>  #define PCIE_SHARED_RESET		1
>  #define PCIE_NORMAL_RESET		0
> @@ -81,26 +80,19 @@ enum pcie_data_rate {
>  struct meson_pcie_mem_res {
>  	void __iomem *elbi_base;
>  	void __iomem *cfg_base;
> -	void __iomem *phy_base;
>  };
>  
>  struct meson_pcie_clk_res {
>  	struct clk *clk;
> -	struct clk *mipi_gate;
>  	struct clk *port_clk;
>  	struct clk *general_clk;
>  };
>  
>  struct meson_pcie_rc_reset {
> -	struct reset_control *phy;
>  	struct reset_control *port;
>  	struct reset_control *apb;
>  };
>  
> -struct meson_pcie_param {
> -	bool has_shared_phy;
> -};
> -
>  struct meson_pcie {
>  	struct dw_pcie pci;
>  	struct meson_pcie_mem_res mem_res;
> @@ -108,7 +100,7 @@ struct meson_pcie {
>  	struct meson_pcie_rc_reset mrst;
>  	struct gpio_desc *reset_gpio;
>  	struct phy *phy;
> -	const struct meson_pcie_param *param;
> +	struct phy *shared_phy;
>  };
>  
>  static struct reset_control *meson_pcie_get_reset(struct meson_pcie *mp,
> @@ -130,13 +122,6 @@ static int meson_pcie_get_resets(struct meson_pcie *mp)
>  {
>  	struct meson_pcie_rc_reset *mrst = &mp->mrst;
>  
> -	if (!mp->param->has_shared_phy) {
> -		mrst->phy = meson_pcie_get_reset(mp, "phy", PCIE_SHARED_RESET);
> -		if (IS_ERR(mrst->phy))
> -			return PTR_ERR(mrst->phy);
> -		reset_control_deassert(mrst->phy);
> -	}
> -
>  	mrst->port = meson_pcie_get_reset(mp, "port", PCIE_NORMAL_RESET);
>  	if (IS_ERR(mrst->port))
>  		return PTR_ERR(mrst->port);
> @@ -162,22 +147,6 @@ static void __iomem *meson_pcie_get_mem(struct platform_device *pdev,
>  	return devm_ioremap_resource(dev, res);
>  }
>  
> -static void __iomem *meson_pcie_get_mem_shared(struct platform_device *pdev,
> -					       struct meson_pcie *mp,
> -					       const char *id)
> -{
> -	struct device *dev = mp->pci.dev;
> -	struct resource *res;
> -
> -	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, id);
> -	if (!res) {
> -		dev_err(dev, "No REG resource %s\n", id);
> -		return ERR_PTR(-ENXIO);
> -	}
> -
> -	return devm_ioremap(dev, res->start, resource_size(res));
> -}
> -
>  static int meson_pcie_get_mems(struct platform_device *pdev,
>  			       struct meson_pcie *mp)
>  {
> @@ -189,14 +158,6 @@ static int meson_pcie_get_mems(struct platform_device *pdev,
>  	if (IS_ERR(mp->mem_res.cfg_base))
>  		return PTR_ERR(mp->mem_res.cfg_base);
>  
> -	/* Meson AXG SoC has two PCI controllers use same phy register */
> -	if (!mp->param->has_shared_phy) {
> -		mp->mem_res.phy_base =
> -			meson_pcie_get_mem_shared(pdev, mp, "phy");
> -		if (IS_ERR(mp->mem_res.phy_base))
> -			return PTR_ERR(mp->mem_res.phy_base);
> -	}
> -
>  	return 0;
>  }
>  
> @@ -204,20 +165,40 @@ static int meson_pcie_power_on(struct meson_pcie *mp)
>  {
>  	int ret = 0;
>  
> -	if (mp->param->has_shared_phy) {
> -		ret = phy_init(mp->phy);
> -		if (ret)
> -			return ret;
> +	ret = phy_init(mp->phy);
> +	if (ret)
> +		goto err;
>  
> -		ret = phy_power_on(mp->phy);
> -		if (ret) {
> -			phy_exit(mp->phy);
> -			return ret;
> -		}
> -	} else
> -		writel(MESON_PCIE_PHY_POWERUP, mp->mem_res.phy_base);
> +	ret = phy_init(mp->shared_phy);
> +	if (ret)
> +		goto exit;
> +
> +	ret = phy_power_on(mp->phy);
> +	if (ret)
> +		goto shared_exit;
> +
> +	ret = phy_power_on(mp->shared_phy);
> +	if (ret)
> +		goto power_off;
>  
>  	return 0;
> +
> +power_off:
> +	phy_power_off(mp->phy);
> +shared_exit:
> +	phy_exit(mp->shared_phy);
> +exit:
> +	phy_exit(mp->phy);
> +err:
> +	return ret;
> +}
> +
> +static void meson_pcie_power_off(struct meson_pcie *mp)
> +{
> +	phy_power_off(mp->shared_phy);
> +	phy_power_off(mp->phy);
> +	phy_exit(mp->shared_phy);
> +	phy_exit(mp->phy);
>  }
>  
>  static int meson_pcie_reset(struct meson_pcie *mp)
> @@ -225,16 +206,13 @@ static int meson_pcie_reset(struct meson_pcie *mp)
>  	struct meson_pcie_rc_reset *mrst = &mp->mrst;
>  	int ret = 0;
>  
> -	if (mp->param->has_shared_phy) {
> -		ret = phy_reset(mp->phy);
> -		if (ret)
> -			return ret;
> -	} else {
> -		reset_control_assert(mrst->phy);
> -		udelay(PCIE_RESET_DELAY);
> -		reset_control_deassert(mrst->phy);
> -		udelay(PCIE_RESET_DELAY);
> -	}
> +	ret = phy_reset(mp->phy);
> +	if (ret)
> +		return ret;
> +
> +	ret = phy_reset(mp->shared_phy);
> +	if (ret)
> +		return ret;
>  
>  	reset_control_assert(mrst->port);
>  	reset_control_assert(mrst->apb);
> @@ -286,12 +264,6 @@ static int meson_pcie_probe_clocks(struct meson_pcie *mp)
>  	if (IS_ERR(res->port_clk))
>  		return PTR_ERR(res->port_clk);
>  
> -	if (!mp->param->has_shared_phy) {
> -		res->mipi_gate = meson_pcie_probe_clock(dev, "mipi", 0);
> -		if (IS_ERR(res->mipi_gate))
> -			return PTR_ERR(res->mipi_gate);
> -	}
> -
>  	res->general_clk = meson_pcie_probe_clock(dev, "general", 0);
>  	if (IS_ERR(res->general_clk))
>  		return PTR_ERR(res->general_clk);
> @@ -562,7 +534,6 @@ static const struct dw_pcie_ops dw_pcie_ops = {
>  
>  static int meson_pcie_probe(struct platform_device *pdev)
>  {
> -	const struct meson_pcie_param *match_data;
>  	struct device *dev = &pdev->dev;
>  	struct dw_pcie *pci;
>  	struct meson_pcie *mp;
> @@ -576,18 +547,13 @@ static int meson_pcie_probe(struct platform_device *pdev)
>  	pci->dev = dev;
>  	pci->ops = &dw_pcie_ops;
>  
> -	match_data = of_device_get_match_data(dev);
> -	if (!match_data) {
> -		dev_err(dev, "failed to get match data\n");
> -		return -ENODEV;
> -	}
> -	mp->param = match_data;
> +	mp->phy = devm_phy_get(dev, "pcie");
> +	if (IS_ERR(mp->phy))
> +		return PTR_ERR(mp->phy);
>  
> -	if (mp->param->has_shared_phy) {
> -		mp->phy = devm_phy_get(dev, "pcie");
> -		if (IS_ERR(mp->phy))
> -			return PTR_ERR(mp->phy);
> -	}
> +	mp->shared_phy = devm_phy_optional_get(dev, "shared");
> +	if (IS_ERR(mp->shared_phy))
> +		return PTR_ERR(mp->shared_phy);

This "shared" phy doesn't appear in patch 3 (bindings) !

Not sure it's the best way to do this, maybe you could chain the MIPI
phy from the PCIE phy instead, so it's the PCIE phy to enable/power/reset the
MIPI PHY instead of the PCIe driver.

But still, here you don't really model the MIPI PHY, it uses way more than
a register in HHI... so at least you should add all the resources needed
if you wanted to model a true MIPI PHY. i.e. MIPI PHY registers, clocks, resets
& co if you want to model the MIPI PHY as is.

Neil

>  
>  	mp->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>  	if (IS_ERR(mp->reset_gpio)) {
> @@ -636,30 +602,16 @@ static int meson_pcie_probe(struct platform_device *pdev)
>  	return 0;
>  
>  err_phy:
> -	if (mp->param->has_shared_phy) {
> -		phy_power_off(mp->phy);
> -		phy_exit(mp->phy);
> -	}
> -
> +	meson_pcie_power_off(mp);
>  	return ret;
>  }
>  
> -static struct meson_pcie_param meson_pcie_axg_param = {
> -	.has_shared_phy = false,
> -};
> -
> -static struct meson_pcie_param meson_pcie_g12a_param = {
> -	.has_shared_phy = true,
> -};
> -
>  static const struct of_device_id meson_pcie_of_match[] = {
>  	{
>  		.compatible = "amlogic,axg-pcie",
> -		.data = &meson_pcie_axg_param,
>  	},
>  	{
>  		.compatible = "amlogic,g12a-pcie",
> -		.data = &meson_pcie_g12a_param,
>  	},
>  	{},
>  };
> 

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